Guide to Protective Coatings: Inspection and Maintenance Tom N. Bortak
United States Department of the Interior Bureau of Reclamation Technical Service Center
September 2002
Acknowledgments Several Rec Reclamation lamation em ploy ees help help ed p r ep a r e t h is g u id e, a n d th eir co n tr ib u tio n is greatly ap ap pre ciated. ciated. These p eople are are Kurt F. von Fay, materials engineer, w ho set up f u n d i n g a n d s h o w e d g r e a t p a t i e n ce ce o v e r th th e w riting riting interval; D. Thom Thom as (Tom) John John son, m aterials engineer, for his corrosion exp ertise contribution; Gregory J. Myers a nd Richard Richard A. Pep in, mater ials engineering technicians, technicians, for their initial initial review in ferreting ferreting ou t obviou s
errors; an an d Robert Rood Rood , ed ed itor, itor, for his n u m e r o u s “ I d o n ' t u n d e r s t an an d ” c o m m e n t s th th a t forced m e into w riting riting a clearer, clearer, more concise, a n d u n d e r st st a n d a b l e d o cu cu m e n t. t. A d e b t o f g r a ti ti t u d e i s e x p r e s s ed ed t o N A C E International, Society of Protective Coatings, and Un iversity iversity of M issou issou ri-Roll ri-Rolla, a, Coating Coating Institute Institute for prov iding all the courses courses and r e f e r en en c e s t h at at m a d e t h i s g u i d e p o s s ib ib l e .
Preface In recent years, coating coating techn ology has changed d ram atical atically. ly. The d riving force b e h i n d t h e c h a n g e h a s b e e n r e g u la t io n s a f fe fe c ti ti n g t h e e n v i r o n m e n t a n d p e r s o n n e l health and safety. For exam exam ple, regu lations lations related to d u st particles particles from ab rasive blasting, blasting, volatile volatile organic comp comp ou nd (VOC) emissions, emissions, a n d h a z a r d o u s m a t e r ia ia l s su su c h a s l e a d , c h r o m a t e , a n d o t h e r h e a v y m e t a ls ls h a v e changed. Before Before the lat e 1980s, 1980s, coating m aterials w ere m o r e t o l e ra ra n t o f l es es s t h a n o p t im im u m s u r f a ce ce p r ep a r a tio n co n d iti o n s b eca u se p a in t formu lation lation contained high VOCs to allow allow the m aterial to wet or p enetrate steel steel surfaces. surfaces. The m o s t su su c c e ss ss fu fu l w e r e r e d l e a d p r i m e r s a n d vinyl resins; resins; ho wev er, regulations regulations hav e d iscoura iscoura ged the use of these materials. materials. Paint m a n u f a ct ct u r e r s r e f o r m u l a te te d t h e ir ir c o a t i n gs gs t o c o m p l y w i t h n e w r e g u l a t io io n s . T h i s h a s l e d t o the d evelopm ent of a w ide variety variety of high-tech high-tech coatin coatin g m aterials aterials th th at are m uch m ore sensitive sensitive t o s u r f a ce ce p r e p a r a t i o n a n d e n v i r o n m e n t a l app licati lication on pra ctices. ctices. Th e Fede Fede ral H ighw ay A d m i n is is t r a ti ti o n h a s e s t im im a t e d t h a t u p t o 8 0 p e r c en t o f a ll p r e m a t u r e co a t in g f a ilu r e s o n
b r id g e s tr u ctu r es ar e p a r tia lly or co m p let ely caused by d efici eficient ent surface prep aration or app licati lication on p ractices. ractices. Several organizations organizations such as the Am erican erican Society Society for Testing Testing an d Materials, N ACE Intern Intern ational, and the Society Society for Protective Protective Co atings hav e issued c on on s e n s u s s t an an d a r d s t o m i n im im i z e s u r f a ce ce p r ep ar a ti o n a n d ap p lic at io n in a d eq u ac ie s. This gu ide is not intend intend ed to be all encomp assing; rather, it is is intend ed to be an introdu ction ction to specific specific referen referen ce standard s a n d t e st st p r o c ed ed u r e s r e l a te te d t o s u r f a ce ce p r e p a r a t i on , a p p lic a t io n , te s tin g , a n d m aintenance of coatings. coatings. Explanations and p r oc ed u r es of r efe ef e r en ce s ta n d a r d s c it ed w ith in t h i s g u i d e a r e a b b r e v i a t ed ed t o d e v e l o p a w orking basis. Th e user is encourag encourag ed to read r e fe fe r e n c e st st a n d a r d s a n d c o a t i n g m a n u a l s f o r a m o r e t h or or o u g h u n d e r s t an an d i n g . T h e g u id e focu focu ses on n ew con con struction struction coatings, coatings, existi existing ng infrastructure coating coating m aintenance, and galvanized coatings of ferrous sub strates for m etalwork items coated coated in the fiel field d . In general, this gu ide follows follows the Bureau of Recla Reclam m ation ation ’s (Recla (Reclam m ation ation ) coatin coatin g gu ide specifications.
Contents Page Chapter I—Intr I—Introd od uction and Backgroun Backgroun d . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1. Sta nd ar d s . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2. Coa tin g Re fe re nc es . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3. Ter m ino log y . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4. Co rr os io n . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5. Ser vice Ex po su re . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1 1 1 1 1 5
Chapter II—Materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6. Co m po n en ts o f Co at ings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7. Coa tin g T yp es . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Ge ne ric Co at ings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5 5 7 7
Chapter III—Sp III—Sp ecifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9. Con stru ction Spe cification cification Ins titu te . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10. Reclam ation C oat ing Sp ecifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11. Coat ing Tab u lations an d Cate gor ies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12. Man u facturer' s Prod u ct Data an d Ap p lication lication Sheets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13. Ad d en du m s a nd Mo dificatio n s . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
11 11 11 12 13 14
8.
Chapter IV—Inspe ctor' ctor's R ole . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14. Pr im ar y Re sp on si bi lities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15. Dai ly Resp o ns ib ilities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16. M at er ial Ap p ro va l . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17. Do cu m en ta tion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18. Inst ru m en ts, Gau ges , and Tools . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
19. 20. 21.
15 15 15 16 16 17 Su bs tr at e Ins p ectio n . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 Coat ing Ins p ection Ch ecklist Sheet . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 Pre coa tin g C on fer en ce . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 ............... .................... . . .. . . . . . . . .. . . . . . . . .. . . . . . . .. . . . . . . . . . . . .. . . . . . . .. . . . . . . . . .. . . . . . .. . . . . . . . .. . . . . . . .. . . . . . . . .. . . . . . . .. . . .
19 19 19 19
.................................... . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . .. . .. . .. .. . .. . . . . . . .. . .. . .. . . . . . . . . . .. . . .. . . . . .. . . .. . . . . . . .. . . .. . . .. . . . . N ozz le Blast P res su re . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Su rf ace Pr ep ar at ion M et ho d s . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Ph ot og ra ph ic Insp ection Stan da rd s . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Alt ern ative Su rfa ce Prep ara tion M eth od s . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
21 21 23 23 24 25 27 30
Chapter V—M aterial aterial Storage, Storage, Con tainers, and Sh elf Life 22. Sto r ag e . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23. Co nt ain er s . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24. Sh elf Life . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Chapter VI—Surface Preparation . . . . . . . . . . . . . . . . . . . . 25. Su rfa ce C on ta m ina n ts . . . . . . . . . . . . . . . . . . . . . . . . . 26. P re sur face Trea tme n t . . . . . . . . . . . . . . . . . . . . . . . . . 27. Ab ra si ve Blas t Ma te ria l . . . . . . . . . . . . . . . . . . . . . . . .
28. 29. 30. 31.
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Page Chapter VII—Environmental Conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33 32. En vir on m en ta l Facto Facto rs Af fecting Co atin gs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33 Chapter VIII—Ap VIII—Ap plication and Curing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33. Ap p lication lication Tem p eratu re an d H u m idity Re strictions strictions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34. Co at ing L ay ers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35. M ixin g . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36. Ap plic ation M et ho d . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
37. 38.
35 35 35 36 36 Ap pl icat ion T echn iq ue . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39 Dr yin g, Recoa ting , and Cu rin g . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
Chapter IX—F IX—Field ield In spection and Testing . . . . . . . . . . 39. Su rf ace Pr ep ara tio n Tes ts . . . . . . . . . . . . . . . . . . . . 40. W et Film Th ickn ess . . . . . . . . . . . . . . . . . . . . . . . . . 41. H ar d en ed Pai nt ed Su rf aces . . . . . . . . . . . . . . . . . . 42. De st ru ct ive T es t Me th od s . . . . . . . . . . . . . . . . . . . .
................. ................. . .. . . . . . . .. . . .. . . .. . . . . . . .. . . . .. . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . .. . .. . .. . .. . .. .. . .. . .. . . . . . . .. . .. . .. . . . . . . .. . . .. . . .. . . . . . . .. . . . .. . .
.... .. . . .. . . .. . . .. . .
41 41 42 42 45
.............. ............................ .. . . .. . . . . . . .. . . . . . . .. .. . . .. . . . . . . .. . . .. . . . . .. . . .. . . . . . . .. . . . .. . . . . . . .. . . . . . . .. .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . .. . . .. . . . . . . .. . . . . . . .. .. . . .. . . . . . . .. . . .. . . Tox ic-Based Pai nts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . W ork er Pr otec tion f rom Toxic-Based Pain ts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Lea d Ex pos u re Le vels by Rem ov al Me tho d s . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Co rr ec tive A ction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Ma te ria l Selectio n F acto rs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Sched u ling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
47 47 47 47 47 49 50 50 51 52 52
Chapter X—Ma X—Ma intenanc e Coating Coating s . . . . . . . . . . . . . 43. De fini tion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44. Pu rp ose . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45. Risk Ev alu at ion . . . . . . . . . . . . . . . . . . . . . . . . 46. Ins p ectio n . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
47. 48. 49. 50. 51. 52.
Chapter XI—Galvani XI—Galvani zing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53. Ga lv an iz ing M eth od s . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54. Zin c Cor ros ion an d Serv ice Life . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55. Z inc C h em i cal React io n s . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56. Con tam inan ts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
57. 58.
53 53 54 54 54 Su rf ace P re p ar at ion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55 Co at ing s . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57
Chapter XII—Coating Failures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59. M at er ial Select ion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60. Fo rm u latio n . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61. Ad he si on . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62. Su bst rat e . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63. Ap p lica tion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
64. 65.
59 59 59 61 61 62 De s ign . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63 Ex teri or For ces . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67
Bibliography . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69
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Append App endices ices A B C D E F G H I J K L M
Organ izational izational Sou Sou rces for Stand ard s and References References R ea e a d i ng ng S o ur ur ce ce s I n s p e c ti tio n C h e c k li lis t R ef ef er er e n c e S ta ta n d a r d s C it it ed ed i n G u i d e I n s p e c ti ti on on E q u i p m e n t E x a m p l e o f In s p e c t i o n D a i ly ly C h e c k Sh e e t Proced ur e for for Detecting Moistu re and Oil in in Com p ressed A ir (ASTM (ASTM D 4285) 4285) P r o c e d u r e fo fo r D e t e c ti ti n g C h l o r id id e s a n d S o lu lu b l e Sa Sa l ts ts in in A b r a s iv iv e s b y C o n d u c t iv iv i t y M e t h o d P r o c e d u r e s fo fo r D e t e ct ct in in g C h l o r id id e Io Io n i n W a t e r P r o c e d u r e s f o r D e t e r m i n in in g Bl Bl a s t C l e a n in in g A i r P r es es s u r e D e t e r m i n a t io io n o f E n v i r o n m e n t a l F a ct ct o r s P r o c e d u r e s f or or D e t ec ec t in in g C h l o r i d e Sa Sa l t s o n P r e p a r e d o r E x is is t in in g S u r f a ce ce s Determ ining Surface Profile Profile of Blast-Cle last-Cleaned aned Steel Steel Using Using Rep lica lica Tap Tap e (NAC E RP0287 RP0287 or ASTM D 4417, 4417, Method C) P r oc ed u r es for fo r M ea su r in g W et Film Fi lm Th ick n es s ( A STM D 44 14 ) W e t F il il m T h i ck ck n e s s F o r m u l as as a n d E x a m p l e C a l cu cu l a t io io n s P r o c ed ed u r e s f or or D r y F il il m T h i ck ck n e s s G a u g e s (S (S SP SP C -P -P A 2 ) a n d E x a m p l e Proced ur es for for Discon Discon tin tin uity (Holid (Holid ay) Testi Testin n g (NA CE RP RP 0188) 0188) Proced ur e for Mech Mech anical anical (Pu llof lloff) f) Ad hesion Testing Testing (ASTM (ASTM D 4541; 4541; Ann ex A2) P r o c ed ed u r e f o r H y d r a u l i c A d h e s io io n T e st st i n g (A (A S TM TM D 4 54 54 1; 1; A n n e x A 3 ) P r o c e d u r e fo fo r M e a s u r i n g D r y F il il m T h ic ic k n e s s b y D e s t r u c t iv iv e M e a n s W i th th T o o k e G a u g e (ASTM D 4138) 4138) Procedu res for SSPC-VI SSPC-VIS S 2 (20 (2000 00 Revision) Revision) Procedu re to to Determine the Presence Presence of Soluble Soluble Lead and Insoluble Lead Lead Chr om ate in Coatings Procedu re to Determ ine the Presence Presence of Chro m ate in in Coatings D e t er er m i n a ti ti o n o f T o x ic ic M e t a ls ls i n H a r d e n e d P a i n t
N O P Q R S T U V W X
Figures Fig ur e 1
Pa ge Co m po n en ts of coat ing s . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Tables T a bl e 1 2 3 4 5 6 7 8 9 10
Pag e N u m ber of spot m easurem ents based on total coated surface area . . . . . . . . . . . . . . . . . . . T y p i ca ca l a n d m a x im im u m l ea ea d e xp x p o s u r e l e ve v e ls ls in m i cr cr o g ra r a m s p e r c u bi b i c m e te te r b y r e m ov a l m e t h o d . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Gal van izing m etho d s . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Form ula tion-related failures for org anic coatings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Form ula tion-related failures for inorg ani c coatings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Ad hes ion -re lated failur es . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Sub str ate- related failur es . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Ap p lication-re late d failu res . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Des ign -re lated failur es . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Failur es rel ated t o ext eri or forc es . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
44 51 53 60 61 62 63 64 66 67
ix
Chapter I Introduction and Background Protective or indu strial coatings are the p r i m a r y m e a n s e m p lo y e d b y t h e Bu r e a u o f Reclam Reclam ation (Reclama (Reclama tion) to control control corrosion. Hy d rau lic structu res are typ ically ically constructed with ferrous metals and are sub ject to corrosion. corrosion. Man y Reclama Reclama tion structures are 50 years old, and some are a p p r o a c h i n g 10 10 0 y e a r s . T h e s e st st r u c t u r e s a r e e x p e c t e d t o c o n t i n u e f u n c t io io n i n g i n t o t h e foreseeable futur e. Protective coatings influence th e life, life, safety, safety, op erating effici efficiency, ency, a p p e a r a n c e , a n d e c o no no m y o f th th e s e s t ru ru c t u r e s . A coating's effec effectiveness tiveness d ep end s on selecting c o a t in in g m a t e r i a l t h a t c o r re re c t l y m a t c h e s t h e i n te te n d e d s e r v i ce ce e x p o s u r e f o r th th e m e t a l w o r k . In the pa st, coating m aterial selection selection wa s ba b a s e d o n F e d e r a l, m il it a r y , o r R e cla m a t io n formu lations; how ever, nearly all these f o r m u l a t i o n s h a v e b e en en w i t h d r a w n . T o d a y , s e le le c t io io n i s b a s e d o n s e r v i c e e x p o s u r e t y p e a n d the resu lts of accelerate accelerate d p erform ance testing testing o f c o m m e r c i al al ly ly a v a i l a bl bl e p r o d u c t s .
1. Standards.— Form erly, Reclam Reclam ation p r o v i d e d n a r r a t iv e s t a n d a r d s a n d d e fin i t io n s for specifying specifying mat erials, surface prep aration, a p p l ic ic a t io io n , a n d i n s p e c t io io n . H o w e v e r , R e c la la m a t i o n n o w a d o p t s i n d u s t r i a l s t a nd nd a r d s , w h e r e a p p l i c a b le le . T h e fo fo l lo lo w i n g o r g a n i z a t io io n s ( s e e a p p e n d i x A f o r a d d r e s s e s , t e le le p h o n e n u m b e r s , a n d w e b s i te te s ) a r e r e f e r e n c e d t h r o u g h o u t t h i s g ui ui d e : •
A m e r ic ic a n So So ccii e ty t y fo f o r Te Te sstt in in g a n d Ma terials terials (ASTM).
•
N A C E In I n te t e rn r n a t io i o na n a l (f (f or o r m er e r ly l y ca c a ll l le d N a t io n a l A s s o cia ci a t io n o f C o r r o s io n Engineer s) (NA CE).
•
S o ccii e t y fo fo r P r ot o t e ct ct iv iv e C o at at in g s (form (form erly called called Steel Structures Painting Cou ncil) (SS (SSPC). PC).
2. Coating References.— The coating i n s p e c t o r i s no no t e x p e c t e d t o h a v e t h e e x p e r t i s e of a coating chem ical ical form form ulator or a coating e n g i n e e r , b u t s h o u l d b e r e a s o n a b l y fa fa m i l ia ia r w i th th t h e m a t e r i al al s b ei ei n g a p p l ie ie d . T h is is g u i d e is is intended to provided th e m ost basic b ac k g ro u n d on g en er ic m at er ia l ty p es , s u rf a ce p r e p a r a t io n , a p p li c a tio ti o n , a n d in s p e ct io n m e t h o d s . T he he r e a d e r i s en en c o u r a g e d t o p u r s u e r e la la t e d c o a t in in g r e fe fe r e n c e s l is is t e d in a p p e n d i x B. B.
3. Terminology.— T h e w o r d “ c o a titi n g ” i s a g e n e r i c t e r m a n d i n c lu lu d e s “ p a i n t .” .” In t h e m ost genera l terms, a “coating” is protection a g a i n s t co co r r o s io io n , w h e r e a s a “ p a i n t ” m a y h a v e a d d i t io io n a l p r o p e r t i e s su su c h a s c o lo lo r o r u l t r a v i o le le t s cr cr e e n i n g p i g m e n t s . T h e t e r m s “ c o a t in in g ” a n d “ p a i n t ” a r e u s e d i n t e r c h a n g e a b l y t hr hr o u g h o u t t h i s g u i d e . O t h e r t e r m s o f t en en u s e d t o g e t h e r a r e “ c o a t i n g s ” a n d “ l in in i n g s . ” In g e n e r a l , w h e n d e s c r ib ib i n g t h e interior surfaces of pipes or tank s, the term “linings” is us ed to iden tify tify the interior s u r f a c e s a n d “ c o a t i ng ng s ” i s u s e d t o i d e n t i f y t h e exterior su rfaces. rfaces.
4. Corrosion.— T h e p r i m a r y r e a s o n f o r coating steel is is to preven t corrosion. corrosion. Corrosion of me tals is is an electrochem ical reaction that c a n b e c o n t r o l le le d b y i n t e r f e r in in g w i t h o n e o r m o r e o f th th e f o u r r e q u i r ed ed e le le m e n t s o f a corrosion cell: cell: (1) (1) anod e (corrod (corrod ing area); (2) (2) cathod e (non corrod ing area); (3) (3) electrolyte electrolyte ( w a t e r o r m o i s t u r e i n a t m o s p h e r e , i m m e r s io io n , or soil); soil); and (4) (4) metallic path (betw een tw o d i f fe fe r e n t m e t a ls ls o r w i t h in in t h e s a m e m e t a l) l) . E li li m i n a t e a n y o n e o f t he he f o u r r e q u i r e d e l e m e n t s a n d t h e c o r r o s io io n p r o c e ss ss w i ll ll s t o p . T h e m o s t c o m m o n t y p e s o f c o r r o s io io n e n c o u n t e r e d o n R e cl cl a m a t i o n f e r r o u s metalwork are:
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Guide to Protective Protective Coatings: Coatings: Inspection and Maintenance
(a) Uniform Corrosion.— C o r r o s i o n t h a t o c cu cu r s m o r e o r l e s s u n i f or or m l y a n d r e s u l t s in in r u s t a n d m e t a l l o ss ss o v e r t h e m e t a l s ur ur f a c e .
(b) Galvanic Corrosion.— C o r r o s i o n t h a t o c cu cu r s o n t h e m o r e a c t iv iv e m e t a l o f t w o d issim issim ilar ilar m etals that are electricall electrically y coup led togeth er in the sam e electrolyte electrolyte (e.g., (e.g., water). T h e m o r e a c t iv iv e m e t a l w i l l co co r r o d e .
(c) Crevice Corrosion.— Crevice corrosion is a form of localized localized corrosion tha t occurs in c r e v ic ic e s w h e r e t h e e n v i r o n m e n t d i ff ff e r s fr fr o m t h e su s u r r o u n d i n g b u lk l k e n v i r on on m e n t . T h e d i f fe fe r e n t e n v i r o n m e n t s r e s u l t i n c o r r o s i on on b e c a u s e o f d iffe if fe r e n c e s i n c o n c e n t r a t io n (e.g., (e.g., oxygen, pH , an an d ferric ferric ions). If there is an oxygen concentrati on difference, corrosion w i ll ll p r o c e e d a t c r e v i ce ce s w h e r e t h e r e i s l e s s o x y g en e n t h a n in t h e e n v ir ir o n m e n t s u r r o u n d i n g t h e c re re v i c e . C r e v i c es es a re re f o rm rm e d w h e n t w o s u r f a c es es a r e i n p r o x i m i t y t o o n e a n o t h e r , s u c h a s w h e n t w o m e t a l s u r f a ce ce s a r e a g a i n s t o n e another, w hen a gasket is against a surface, or w h e n a n g l e ir ir o n s a r e p l a c e d b a c k t o b a ck ck . C r e v i c e co co r r o s i o n c an an o c c u r u n d e r d e p o s i t s (e.g., (e.g., barnacles, dirt, grease, and slim slim e) on a metal surface. localized (d) Pitting corrosion.— A form of localized c o r r os os i o n w h e r e t h e d e p t h o f p e n e t r a t io io n i s g r e a t e r t h a n t h e d i a m e t e r o f t h e a ff ff e ct ct e d a r e a .
(e) Cavitation corrosion.— The m etal loss c a u s e d b y t h e f o r m a t i o n a n d c o ll ll a p s e o f v a p o r bu bb l es i n a li qu id n e ar a m et al su rf a ce . Th e app ear ance of cavitation is similar similar to pitting, e x ce ce p t t h a t p i t t e d a r e a s a r e c l o s e ly ly s p a c e d a n d t h e s u r f a c e is is c o ns ns i d e r a b l y r o u g h e n e d .
(f) Erosion-corrosion.— The accelerated m etal loss from an initial corrosion m echan ism associated w ith high-velocity flows flows and abrasion. Erosion-corrosion Erosion-corrosion is characterized b y g r o o v e s , g u l li e s, w a v e s , a n d r o u n d e d r i d g e s o r v a l l e y s a n d e x h i b it it s a d i r e ct ct i o n a l f lo lo w p a t t e r n .
r e d e p o s it it o f t h e c at at h o d i c c o n s t it it u e n t . T h e element rem oved is always anod ic to the m atrix. With dealloying, there is no m etal loss, d i m e n s i o n c h a n g e s , c r a c ks ks , o r g r o o v e s ; h o w e v e r , t h e a ff f fe c t e d a r e a m a y b e e v i d e n t b e c a u s e o f a co l o r ch a n g e . Th e a f fe c te d a r e a b e co m e s lig h t e r , p o r o u s , a n d lo s e s it i t s o r ig in a l m echan ical ical p rop erties (i.e (i.e., ., it becomes brittle a n d l o s e s t e n s i le le s t r en en g t h ) . T w o c o m m o n f o r m s o f d e a l lo lo y i n g a r e : selective d issolut issolut ion Dezincification.— The selective of zinc from bra ss alloys. It is is recognized by a color change (e.g., (e.g., from its original yellow b r a s s c o lo r t o a d i st in c tly tl y r e d , co p p e r y appearance). selective Degraphitization.— The selective d issolu issolu tion of iron iron from som e cast irons, u s u a l ly ly g r a y c a s t ir ir o n s . I t no no r m a l ly ly p r o c e e d s u n i fo fo r m l y i n w a r d f r o m t h e s u r f a c e , l e a v in in g a p o r o u s m a t r ix a llo y t h a t i s c o m p o s e d m o s t ly o f c a r b o n . D e g r a p h i t iz iz a t i o n c an an b e r e c o g n i z e d b y a change fro m an or iginal silver-gra silver-gra y color to a d a r k g r a y . T h e a ff ff ec ec te te d m e t a l c a n b e e a s i ly ly c u t o r p i e r c e d w i t h a k n i fe fe . ecified 5. Service Service Exposure.—Coatings are sp ecified by b y se r v i c e e x p o su r e o r t h e e n v i r o n m e n t t h e coating w ill ill be subject subject to. The following following ar e t h e b a s ic ic s e r v i ce ce e x p o s u r e s d e f i n e d b y Reclamation: •
A t m os os p h e r i c N N
Indoors Outdoors
•
Bu r i a l
•
I m m er er s io n
•
C om o m p le l e t e, e , p a rt r t i a l, l , or or f lu lu cctt u a t in in g i m m e r s io io n c o n d i t io io n s
•
A tm t m o sp s p h er e r ic ic ex e x p os os u r e su su b je je ct ct t o condensation, high hu m idity, splash, or spray
•
T he h e fo f o ll ll o w in i n g ssu u b e xp x p os o s u r e co co nd n d i t io io ns ns m a y a p p l y t o a n y o f t h e a b ov ov e :
(g) Dealloying or Selective Leaching.— Th e selective selective rem oval of one of the element s of an a l lo lo y b y e i t h e r p r e f e r en en t i a l a t t a ck ck o r c o m p l e t e d issolution issolution of the mat rix, followe followe d by
2
Introduction and Background N
Direct sunlight or UV: sever al coatings, su su ch as ep oxies, oxies, will d e t e r i o r a t e b y c h a l k in in g w h e n exposed to sunlight.
N
Che m ical resistance: exposure s m a y i n c lu lu d e a c i d i c o r a lk lk a l in in e c o n c e n t r a t io io n s , i n d u s t r i a l s m o g , acid rain , sew sew age, or sp ecific ecific chem icals. icals.
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Chapter II Materials C o a t i n g f o r m u l a t io io n i s g e n e r a l ly ly b a s e d o n o r g a n i c , i no no r g a n i c , p o l y m e r , a n d c o -p -p o l y m e r chem istry. istry. It is not th e inten tion of th is c h a p t e r t o d i s cu cu s s c o a t i ng ng c h e m i s tr tr y b u t , r a t h e r , t o p r o v i d e a b a s ic ic k n o w l ed ed g e o f c oa oa t i n g c o m p o n e n t s a n d g e n e r i c c o a t in in g t y p e s specified specified by Re clam clam ation.
6. Components of of Coatings.— Coatings.—All org org anic coatings con con sist sist of thr ee basic comp onen ts: (1) solvent, (2) (2) resin, and (3) (3) pigm ent. N ot all c o a t in in g s c o n t a i n s ol ol v e n t a n d p i g m e n t e d comp onen ts. There are solv solv ent-free (100 (100 p e r c e nt s o l i d s ) c oa t in g s a n d c lea le a r , p i g m e n t free coatings, but n ot resin-free coatings.
W h e n a c o a t in in g i s a p p l ie ie d , t h e s o l v e n t e v a p o r a t e s d u r i n g t h e cu cu r i n g p r o c e s s, s, le le a v i n g o n l y t h e r e si sin a n d t h e p i g m e n t c o m p o n e n t s o n the substrate. The remaining resin and p ig m en ts ar e s om et im es ca ll e d th e “ co a ti n g s o li li d s ,” ,” a n d t h e y f o r m t h e p r o t e c t iv iv e f i lm lm f o r c o r r o si si o n p r o t e c t io io n . ol v e n t s a r e f o r m u l a t ed ed (a) Solvent.— O r g a n i c s ol
C o a t in in g c h e m i c al al fo fo r m u l a t o r s co co m m o n l y g r o u p s o l v e nt nt , re re s i n , a n d p i g m e n t c o m p o n e n t s into two gene ral categor categor ies. T he first first category c o m b i n e s t h e s o lv lv e n t a n d t h e r e s in in t o g e th th e r . The solv solv ent p ortion is called called th e “volatile “volatile veh icle,” icle,” and the resin portion is called th e “non volatile veh icle.” icle.” The com bination of the s o lv lv e n t a n d t h e r e s i n , w h e r e t h e r e s i n is is d issolved issolved in the solvent , is is called called th e “veh icle.” icle.” The second category is the pigmen t. Pigments a r e a d d i t i v es es t h a t i m p a r t s p e c if if ic ic p r o p e r t i e s t o t h e c oa oa t i ng ng a n d a r e su s u b d i v id i d e d i n to to t w o
Solvent (Volatile)
gener al categories: (1) (1) color color and (2) (2) inert inert an d reinforced. Figu Figu re 1 illu illu strates the relationsh ip o f t he he s e co co m p o n e n t s .
Resin (Nonvolatile)
i n t o c o a t in in g s t o p e r f o r m t h r e e e s s e n t i a l fun ctions: ctions: (1) (1) dissolve the resin comp onen t; (2) (2) contro contro l evapora tion for film film forma tion; and (3) red uc e the coating viscosity viscosity for ease of ap plication plication . Solven Solven ts will also also affect affect d ry film film a d h e s io io n a n d d u r a b i li li ty ty c oa oa t i n g p r o p e r t ie ie s . I n gene ral, resins that are less soluble soluble will requ ire either more solvents or stronger solvents to d issolve issolve the resins. T h e t e r m s “ s o lv lv e n t s ” a n d “ t h i n n e r s ” a r e often used interchangeably, but there are d i s t in in c t io io n s w i t h in in a n d b e t w e e n t h e tw tw o te te r m s . T h e t e r m “ s o l v e n t ” c a n i m p l y t w o d i ff ff e re re n t usag es: (1) the solv solv ent or solvent blend s in t h e c o a t in in g f o r m u l a t io io n a t p r e d e t e r m i n e d
Color Pigments
Ve h ic le
Inert and Reinforced
P ig m e n t
Coating
Figure 1.—Components of coatings.
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Guide to Protective Protective Coatings: Coatings: Inspection and Maintenance concentra tion levels; or (2) (2) cleaning cleaning solvents in s t r on on g c on on c en en t r a t io io n s t r en en g t h f or or c le le a n i n g b r u sh e s, r o lle r s, h o se s, a n d o th e r eq u ip m e n t. The usage of the term “th inner” (a thinner is a solvent) is m ost often associated associated w ith the c o a t in in g a p p l i c a to to r a d d i n g a t h i n n e r t o a c o a ti ti n g c o n t a i n e r ( n o r m a l ly ly a b o u t 1 p i n t thinne r to 1 gallon of coating) coating) to redu ce the viscosity viscosity for for ease ease of ap plication plication . Ad d ing thinn er to a coating in th e field is often often called “field thinning.” T h e m a n u f a ct ct u r e r ’s ’s p r o d u c t d a t a s h e e t w i ll ll s p e ci c i fy fy a t h i n n e r a n d a m a x i m u m a m o u n t t o b e u s e d f o r e a c h c o a t in in g t y p e . U s e o f a t h in in n e r n o t r e co co m m e n d e d b y t h e m a n u f ac a c t u re re r c a n c a u s e n u m e r o u s a p p l ic ic a t io io n p r o b l e m s o r p r e m a t u r e fa i lu r e s s u c h a s s e p a r a t i o n o f comp onen ts, coagula tion, too fast fast or too slow d rying, changes in flow c haracteristics, haracteristics, or lifting lifting of p reviou s coats. The followin followin g c o m m o n t h i n n e r s a r e u s e d w i t h t h e a s s o c i a t ed ed generic coating types:
T h in n e r s
C o a t in g s
M i n e r a l s p i r it s
O il s a n d al al k y d s
A r o m a t i cs cs ( b e n z e n e , xylol, toluol toluol e)
C o a l t a r e p o x i es es , alkyds, chlorinated rubbers
Ketones (MEK, MIBK)
Vinyls, epoxies, urethanes
A l co co h o ls l s ( is is o p r op o p y l) l)
P h en e n o li li c ss,, in in or o r g a n ic ic zincs
W ater
A c r y l ic s, s o m e inorganic zincs
S o lv lv e n t s p r o d u c e v a p o r s t h a t a r e h e a v i e r t h a n air and w ill ill collect collect in tank bo ttom s or confined confined a r e a s . T h e k e t o n e s h a v e t h e l o w e s t fl fl a sh sh p o in in t o f t h e o r g a n i c s o lv lv e n t s ; h o w e v e r , a n y s o l v e n t i n t h e r i g h t c o m b i n a t i o n w i t h a i r ca ca n c r e a t e a n explosive combination. Fed Fed eral, State, State, coun ty, city, city, an d local local air q u a l i t y c o n t r o l d i s t r ic ic t s r e g u l a t e t h e a m o u n t o f volatile organ ic solvents (VO (VO C) in in coatings. A s t h e c o a t i ng ng c u r e s , VO VO C s e v a p o r a t e i n t o t h e
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a t m o s p h e r e a n d r e a c t w i t h su su n l i g h t a n d a ir ir p o llu ll u t a n t s to fo r m o z o n e , a k n o w n h u m a n h e a l t h h a z a r d . I n r es es p o n s e , c oa oa t i n g m a n u f ac ac t u r e r ’ s h a v e r e fo fo r m u l a t e d t h e ir ir p r o d u c t s w i th l o w e r s o l v e n t c o n t e n t t o m e e t c u r r e n t V O C r e g u l a t i o n s. s. Reclam Reclam ation specifications specifications requi re the coatings t o m e e t t h e V O C r e g u l a t i o n s “ i n -t -t h e - ca ca n ” o r “as-ma nu factu factu red ” before field field th th inning . Field Field t h i n n i n g o f a c o a t i n g t h a t w i l l e xc xc e e d t h e r e g u l at at e d V O C m a xi x i m u m i s n o t p e r m i t te te d . Reclam Reclam ation sp ecifies ecifies coatings based on the c u r r e n t E n v i r o n m e n t a l P r o t ec ec t i on on A g e n c y (EPA) VOC limits.
(b) Resin.— The resin (frequ (frequ ently called b in d er ) i s t h e f il m fo r m in g com co m p on en t o f a coating. Resins Resins are typically typically a high m olecular w e i g h t s o li li d p o l y m e r t h a t f o r m s l a r g e r e p e a t i n g m o l e cu cu l e s i n t h e c u r e d f il il m . T h e p ri m a r y p u r p o s e of t h e r e s i n i s t o w e t t h e p i g m e n t p a r t i cl e s a n d b i n d t h e p i g m e n t p a r t i cl e s t o g e t h e r a n d t o t h e s u b s t r a t e (h e n c e , t h e t e r m “ b i n d e r ” ) . T h e r e s in in i m p a r t s m o s t o f t h e c o a t in in g p r o p e r t i e s . T h e v a r i o u s t y p e s o f r e s in in s f o r m u l a t e d i n a c o a t i n g w i ll ll d i s p l a y d i s t in in c t p r o p e r t i es es . T h e s e p r o p e r t i e s a r e : • • • • • • •
M e ch ch a ni n is m a n d t im im e o f c u r in in g P e rf r fo r m a nc n c e i n s er e r v ic ic e e xp xp o su su r e ty ty p e P er e r fo fo rm r m a nc n c e o n s ub u b st s t ra r a t e t yp yp e C o m p at a t ib i b il il i t y wi w i t h o th th e r c o a ti t in g s F le le xi xi b il ili ty ty an a n d t ou o u g h n es es s E x t er er io io r w ea e a th t h er e r in in g Ad hesion
N o s in g l e r e s in c a n a c h i e v e a h ig h d e g r e e o f s u c c es es s i n m e e t in in g t h e a b o v e c o a t i n g p r o p e r t i es w i th w i d e v a r i a t io n s a s s o c ia t e d w i th th e a c h p r o p e r t y . T h e r ef ef o r e , g e n e r i c co co a t in in g t y p e s a r e g e n e r a l ly ly c l a s si si fi fi e d b y t h e p r i m a r y r e s in in t y p e u s e d i n t h e c o a t i n g f o r m u l a t i o n . Typical resins are acrylics, alkyd s, and ep oxy p ol y m e rs . in s o l u b l e a n d a r e (c) Pigment.— P i g m e n t s a r e in t h e h e a v i e r s o li li d p o r t i o n o f a c o a t in in g t h a t typ ically ically settles settles to th th e bottom of th th e container. P i g m e n t s a r e a d d i t i v e s to to t h e c o a t i n g f o r m u l a t io io n t h a t i m p a r t s p e c i fi fi c p r o p e r t i e s t o
Materials a c h i e v e t h e d e s i re re d f i lm lm p r o p e r t i e s . T h e f o ll ll o w i n g p r o p e r t i e s a r e a cc cc o r d e d b y p i g m e n t s , a n d a b r i e f d e s cr i p t i o n i s p r o v i d e d for each.
Color.— N a tu r a l e a r th p ig m en ts (k a ol in clay, magn esium silicate, silicate, calcium calcium carbona te) p ro v i d e c ol o r st ab ili il i ty fr o m u l t ra v i o le t (U V) s u n l i g h t d e t e r i or or a t i o n. n. N a t u r a l e a r t h p i g m e n t s are m ore UV stable than synth etic organic p ig m e n t s.
ld e w c id e s p r e v e n t Milde M ildew w resi sta nce .— M i ld m i l d e w g r o w t h o n t h e d r y f i lm lm c o a t i n g .
Skid Ski d or s lip re sistan sis tan ce.— ce. — A l u m i n u m o xi xi d e or min eral aggregate is add ed in the f o r m u l a t i o n o r a p p l ie ie d t o t h e w e t f il il m t o a c h i ev ev e n o n s li li p s u r f a ce ce s . A l u m i n u m o x id id e i s t h e b e t t e r c h o i c e b e c a u se se m i n e r a l a g g r e g a t e m a y b e c r u sh s h e d u n d e r w e ig h t , p r o v i d i n g m o i s t u r e a cc e ss ss t o t h e su b s t r a t e , a n d p r o m o t in g f u r t h e r c o a tin ti n g d e g r a d a t io n a n d corrosion.
it a n i u m o x i d e h i d e s t h e Opacity.— T it s u b s t r a t e o r p r e v i o u s c o a t i n g c o lo lo r a n d p r o t e ct s t h e b in d e r fr o m U V s u n l ig h t deterioration.
7. Coating Types.— T h e f o llll o w i n g a r e t h r e e ba si c t y p e s of c oa t i ng s: rm s a (a) Barrier.— A c o a t i n g t h a t f o rm
Silica ca an d talc control Wet paint.— Sili viscosity, viscosity, wet film leveling leveling , an an d settling settling bu t p r o v i d e li t tl e h id in g ( op a c it y ) p o w e r .
ba b a r r i e r b e t w e e n t he m e t a l su r fa ce a n d t h e electrolyte electrolyte an d electricall electrically y isolates the m etal. E x a m p l e s a r e e p o x i es es a n d c o a l t a r e p o x i e s. s.
Weather and moisture resistance.—
in g (b) Inhibitive.— P i g m e n t i n a c o a t in
A l u m i n u m l ea ea f s a n d m i c a c eo eo u s ir ir o n o x i d e (MIO) increase increase barrier thickness and force m o i s tu tu r e t o d e t o u r a r o u n d t h e s e p l a t e -l -l ik ik e additives. gm e n t s a d d e d t o Corrosion resistance.— resistance.— P i gm i n h i b i ti ti v e ( p r i m e r ) c o a t in in g s i m p e d e c o r r o si si o n of ferrou s substrat es. Past form form u lations i n cl cl u d e d c h r o m a te t e a n d l ea ea d p i g m e n t s , b u t t h e y a r e se se l d o m u s e d t o d a y b e c a u s e o f e n v i r o n m e n t a l a n d h e a l th th c o n c e rn rn s . T h e f o ll ll o w i n g c h r o m a t e a n d l e a d p i g m e n t s a r e r a r e l y u s e d i n c u r r e n t c o a t i n g f o r m u l a t i on on s : • • • • •
R ed le a d W h i t e le a d Ba ssii c l ea e a d si s i l ic ic o o-- c h hrr om om a te te S t r o n ti t i u m ch c h r o m a te te Zinc chrom a te
The followin followin g are accep accep table altern ative i n h i b i t iv iv e p i g m e n t s : • • • • • •
Ba r i u m m et e t a b o r at at e C al al ci ciu m p ho h o sp s p ho h o si s i li li ca ca te te Z in c ox id e Z i n c p ho h o sp sp ha ha te te Z i n c m ol o l y b d at at e Z i nc nc p h os o s p ho h o si s i li ca t e
p r im e r t h a t is slig sl ig h t l y so lu b le in w a t e r th a t forms a chem ical ical in in hibitor and effectively effectively interferes w ith the electrolyte. electrolyte. Examp les are r e d l e a d a n d c h r o m a t e p r i m e r s (n (n o l o n g e r accep accep table).
(c) Galvanic.— Zinc-rich primer coatings that p rovide galvanic or cathodic protection to ferrous m etal (zinc sacrific sacrifices es itself to pro tect the ferrous meta l). l). Galvani c coatings are effecti effective ve on ly if app lied lied d irectly irectly to bare m etal. lo w i n g g e n e r i c 8. Generic Coatings.— T h e f o l lo coatings and general descriptions are typically specified specified by Reclam ation: or n e a c r y l i c (a) Acrylics.— I n w a t e r - b or c o a t in in g s , t h e r e s i n i s d i s p e r s ed ed i n w a t e r t o f or or m a w a t e r e m u l s i on on . W a t e r - bo bo r n e a c ry ry l i c s are specified specified for atm osph eric exposu exposu res as a p r im e r o r t op co a t a n d h a v e e x ce lle n t co lo r a n d gloss retention. Acrylics cure by coalescence. coalescence. ly n a t u r a l (b) Alkyds.— A l k y d s a r e n o r m a l ly oils (soya, tu tu ng, styrenate) that h ave been c h e m i c a l ly ly m o d i f i e d t o i m p r o v e c u r e r a t e , chem ical ical resistance, and h ard ness. Phen olicolicm o d i f ie ie d a l k y d s a r e s p e c i fi fi e d a s a p r i m e r , a n d silicone silicone alkyd s are specified specified a s the topco at for a t m o s p h e r i c se se r v i ce ce e x p o s u r e s . T h e y a r e n o t
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Guide to Protective Protective Coatings: Coatings: Inspection and Maintenance suitable for alkaline alkaline (concrete or mas onry) s u r f a ce ce s o r e n v i r on on m e n t s . A l k y d s c u r e b y a ir ir oxidation of dry ing oils. oils. in g s a r e (c) Bituminous.— Bi t u m i n o u s c o a t in h e a v y - b o d i ed ed m a t e r i a l s a p p l i e d w i th th a c u t b a c k s o lv lv e n t . T h e y h a v e g o o d m o i st st u r e b a r r i e r resistan resistan ce an d fair to good chem ical ical resistan resistan ce b u t a r e n o t r es is t an t t o so lv e n t s . C o m m e r cia ci a l bi b i t u m i n o u s p r o d u c t s a r e s p e c ifie if ie d o n a l im i te d b a s is b y R e cla m a t io n f o r p r o t e c t io n o f a l u m i n u m s u r f a c e s i n c o nt nt a c t w i t h c em em e n t i t io io u s m a t e r i al al o r s t e e l an an d c op op p e r c ab ab l e w e l d c o n n e c t io io n s . Bi t u m i n o u s co co a t i n g s cu cu r e b y so lv en t e va p o ra tio ti o n . ie s a r e (d) Epoxy, Amine.— A m i n e e p o x ie two-comp onent coatings that are catalyzed ( h a r d e n e d ) b y a n a m i n e cu cu r i n g a g e n t t o p r o d u ce a h a r d , t ig h t l y b o n d e d , ch c h e m ic a l resistan resistan t (alkali, acid, and solven t) pr od u ct, bu t t h e y a r e m o i s t u r e a n d t e m p e r a t u r e s e n s i t iv iv e d u r i n g a p p l ic ic a t io io n . Th e y a r e s p e c i fi fi e d f o r b u r i a l a n d im m e r si o n s e rv ic e e xp o s u r e s, b u t t h e y w i ll ll fa fa d e a n d c h a lk lk i n d i r e ct ct s u n l ig ig h t . A m i n e e p o x i e s c u r e b y c h e m i c a l r e a c t io io n . ie s (e) Epoxy, Polyamide.— P o l y a m i d e e p o x ie a r e t w o c o m p o n e n t c o a ti ti n g s t h a t a r e c a t a l yz yz e d b y a p ol y am id e cu ri n g ag en t to p ro d u ce s u p e r i or or r e s i s t a nc nc e t o w a t e r a n d s a l t s ol ol u t i on on s , b u t t h e y d o n o t p r o v i d e t h e c h e m ic a l r e s is is t a n c e o f t h e a m i n e e p o x y . P o l y a m i d e s h a v e a g r e a t e r f le le xi xi b i li li ty ty t h a n t h e a m i n e epoxies. They are specified specified for bu rial and i m m e r s io io n s e r v i ce ce e x p o s u r e s , b u t t h e y w i l l f ad ad e a n d c h a l k in in d i r e ct ct s u n l i g h t . P o ly ly a m i d e epo xies cur cur e by chem ical reaction. ie s a r e (f) Epoxy, Coal Tar.— C o a l t a r e p o x ie g e n e r a l ly ly a n a m i n e o r p o l ya ya m i d e e p o x y m o d i f i e d w i t h c o a l t ar ar p i t ch ch r e s i n t o p r o d u c e a h i g h - b u i l d f il il m t h a t h a s g o o d c h e m i ca ca l resistance and excellent excellent wa ter resistance. resistance. They h a v e a t e n d e n c y t o b e co co m e b r i t t le le w i t h a g e a n d d e l a m i n a t e b et et w e e n c oa oa t s o r b e n e a t h r e p a i r p a t ch e s . T h e y a r e sp e cifi ci fiee d fo r b u r ia l a n d i m m e r s io io n s e r v i ce ce e x p o s u r e s , b u t t h e y w i ll ll fade and chalk in direct sunlight. Coal tar epo xies cur cur e by chem ical reaction.
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(g) Epoxy, Fusion-Bonded.— Fusion b o n d e d e p o x ie s (c o m m o n l y c a ll e d p o w d e r c o a t in in g s ) a r e c o m p l e t e c o a t in in g s i n p o w d e r f o r m . T h e r e a r e tw tw o a p p l i c at at i o n m e t h o d s , flu flu idized -bed and electrostatic. In the f lu lu i d i z e d - b e d m e t h o d , t h e m e t a l it it e m s a r e p r e h e at e d to a fu s io n te m p e r at u r e a n d i m m e r s e d in in th th e p o w d e r - e p o x y so so l u t i o n . I n t h e e l e ct ct r o s t a t ic ic m e t h o d , t h e e p o x y p o w d e r p a r t icl e s a r e c h a r g e d w it h h i g h v o l ta g e , a n d t h e m e t a l it it e m i s t h e n s p r a y e d . A ft ft e r s p r a y i n g , t h e i t e m i s p l a ce ce d i n a n o v e n t o c u r e a t a b o u t 350 350 to 650 d egrees Fahren heit (F). (F). Fusion b o n d e d e p o x ie s a r e s p e c ifi e d fo r b u r ia l a n d i m m e r s io io n s e r v i ce ce e x p o s u r e s , b u t t h e y w i ll ll f a d e a n d c h a l k in in d i r e ct ct s u n l i g h t a n d a r e b r i t t le . A n e w m a t e r i a l i s fu f u s io n - b o n d e d nylon. This materi al is sup erior to the fusion bo b o n d e d e p ox y a n d w i ll b e in c o r p o r a t e d i n t o Reclam Reclam ation's sp ecific ecification. ation. Pow d er coatings cure by fusion (heat).
(h) Inorganic Zinc Primers.— Primers.— I n o r g a n i c z i n c s a r e p r i m e r s t h a t in c o r p o r a t e a h i g h l o a d i n g ( p o u n d s p e r g a l l o n ) o f m e t a l l ic ic z i n c fo fo r p ig m e n t a t io n ( h e n c e, t h e t er m “ z in c -r ic h ” ) a n d a r e e i t h e r so so l v e n t o r w a t e r b a s e d . D e p e n d i n g o n t h e s o l v e n t a n d r e s in in s u s e d , th th e c o a t in in g m a y b e a z i nc nc - r ic i ch e p o x y o r u r e t h a n e . T h e s e coatings are exclusively exclusively prim ers because they p r o v i d e g a l v a n i c o r c a t h o d i c p r o t e c t io n t o s t e e l sub strate. Inorgan ic zincs are spe spe cifi cified ed for a t m o s p h e r i c a nd nd i m m e r s io io n s e r v i ce ce e x p o s u r e s , b u t t h ey ca n b e t op co a te d to ex te n d th ei r service life. life. Suitable topcoat m aterial selection selection i s re re q u i r e d t o p r e v e n t o u t - g a s s in in g f r o m t h e i n o r g a n i c z in in c t h a t p r o d u c e s s m a l l p i n h o l e s i n the topcoat. Reclam Reclam ation sp sp ecifi ecifies es inorg anic zinc coatings only to fraying surf aces or heated t r e a t ed ed m e t a l w o r k ( A S T M A 3 25 25 o r A S T M A 490). 490). Ap plication requ ires spe spe cial cial skill skillss and k n o w l e d g e . In o r g a n i c z i n c s c u r e b y e it it h e r r e a c t io io n t o w a t e r ( s o lv lv e n t r e d u c ib ib l e ) o r r e a c ti ti o n t o c ar ar b o n d i o x i d e ( w a t e r r e d u c i b l e) e) . (i) Organic Zinc Primers.— Primers.— Organic zincs a r e p r i m e r s t h a t i n c o r p o r a t e a h i g h l oa oa d i n g (pou nd s per gallon) of meta llic llic zinc zinc for p i g m e n t a t i o n w i t h a w i d e v a r i e t y o f s ol v e n t s a n d r e s in in s . D e p e n d i n g o n t h e so so l v e n t a n d
Materials resins used , the the coating m ay be a zinc-rich zinc-rich a l k y d , d r y i n g o i l , e p o x y , o r m o i st st u r e - c u r e d u retha ne. These coatings are exclusively p r im er s b ec a u se th ey p r ov id e g a lv a n ic p r ot e c t i o n t o st e e l s ub s t r a t e o r t h e y a r e u s e d t o r e p a i r d a m a g e d g a l v a n i z e d c o a t i ng ng s o n st st e e l sub strates. Org anic zincs zincs are spe spe cifi cified ed for a t m o s p h e r i c , bu bu r i a l , a n d i m m e r s io io n s e rv rv i c e e x p o s u r e s b u t a r e n o r m a l ly ly t o p c o a t e d t o extend the service life life of of the coatin coatin g. Suitable Suitable top coat material selection selection is required to p r e v e n t o u t- g a ss in g fr o m th e o r g a n ic z in c. O u t - g a ss ss in in g p r o d u c e s sm sm a l l p i n h o l e s i n th th e t o p c o a t . T h e w a y o rg rg a n i c z i n c s c u r e d e p e n d s o n t h e c o a t in in g t y p e .
(j) Polyurethane.— Technically, p o ly u r e t h a n e is a s u b c la s s o f u r e t h a n e . A t w o c o m p o n e n t p o l y u r e t h a n e i s cr cr e a t e d b y c h e m i c a ll ll y c o m b i n i n g a p o l y is is o y a n a t e a n d a p o ly o l to p r o d u c e a n i s o cy a n a t e t h a t h a s a t w o m o d e c u r e m e c h a n i sm sm o f so so l v e n t e v a p o r a t i o n
and chem ical reaction. reaction. Reclamation specifies specifies p o ly u r e th a n e s fo f o r to p co a ti n g co m p a ti b le (i. e ., s a m e m a n u f ac a c t u r er er ) a m i n e a n d p o ly ly a m i d e e p o x i e s t o p r o t e ct ct a g a in in s t d i r e c t s u n l ig ig h t or UV an d to p rovid e specific specific colors. colors. P o ly ly u r e t h a n e s a r e s p e ci ci fi fi e d f o r a t m o s p h e r i c a n d p a r t i a l o r f lu lu c t u a t i n g i m m e r s io io n s e r v i c e exposures. in g s v a r y (k) Urethane.— U r e t h a n e c o a t in w idely in form ulations for specific specific serv serv ice e n v i r o n m e n t s a n d a p p l i ca ca t i o n r e q u i r e m e n t s . Reclam Reclam ation specifies specifies single-compon ent, m o i s t u r e - cu cu r e d u r e t h a n e s . T h e y c u r e f r o m moisture in the atm osphere and can be ap plied t o d a m p s u r f a c e s t ha ha t d o n o t h a v e fr fr e e m o i s tu tu r e p r e s e n t . T h e s e u r e t h a n e s a r e formu lated with various pigmentations and are specified specified in sever al com com binations to suit t h e i n te te n d e d s e r v i ce ce e xp xp o s u r e . T h e se se u r e t h a n e s a r e s p e ci ci fi fi e d f or or a t m o s p h e r i c , b u r i a l, l, and immersion exposures.
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Chapter III Specifications Reclamation constru ction ction jobs jobs are ad vertised t o co co n t r a c t o r s t o p e r f o r m t h e r e q u i r e d w o r k , a n d c on on t r a c to to r s e l ec ec t i on on i s m a d e b y a b i d p r o c e ss . T h e m o s t co m m o n b i d t y p e s a r e lo w p r ice ic e , n e g o ti a te d , fixe f ixe d co st , a n d so le so u r ce . On ce Reclama Reclama tion accep accep ts a contr contr actor’s actor’s bid , a c o n t r a c t e xi xi s ts ts b e t w e e n R e c l a m a t i o n a n d t h e contractor. The contract is often called called a specification. specification. The specification specification can be defined as a written, de tailed, technical description of w o r k t o b e p e r f o r m e d , d e s cr cr i b in in g t h e m a t e r ia ia l s, s, q u a n t i ti ti e s, s, a n d m o d e o f construction. S p e c if if ic ic a t io io n s a r e d i v i d e d i n t o m a n y d i v i s io io n s t o d e s c r i b e t h e v a r i o u s jo jo b r e q u i r e m e n t s a n d m a y i n c lu lu d e g e n e r a l jo b d e s cr cr i p t i o n , subm ittals, pre-existing cond itions, itions, e n v i r o n m e n t a l r e q u i r e m e n t s , a n d t e c h n i ca ca l arch itectu ral, civil civil,, electrical, m echa nical, coating, and cathod ic p rotection discip discip lines. lines. Each d ivision ivision is sometim es called called a te chn ical p a r ag ra p h o r s e ctio ct io n .
9. Construction Specification Institute.— R e cl cl am am a t io io n h a s ch ch a n g e d f r o m a n a r r a t i v e p a r a g r a p h f o r m a t t o th e C o n s t r u c t io n Specificati Specification on Institute (CSI) (CSI) form at for specifications. specifications. CSI format style is more concise a n d u s e s i m p e r a t i v e l a n g u a g e . R ef ef e r e n c e s t a n d a r d s a r e s p e c i fi fi e d t o d e s c r i b e q u a l i t y o f m a t e r ia ia l s , w o r k m o d e , t e s t m e t h o d s , a n d acceptance criteria that are a recognized i n d u s t r y p r a c t ic ic e , t h u s r e d u c in in g t h e n e e d f o r l en en g t h y v e r b i ag ag e . T h e m o s t c o m m o n r e f er er e n c e s t a n d a r d s u s e d i n t h e c o a t in in g s i n d u s t r y a r e A S T M , N A C E , a n d S SP SP C . CSI specifi specifications cations are d ivided into 16 divisions divisions f o r a l l t h e b u i ld ld i n g t r a d e s , a n d e a c h d i v i s io io n m a y b e f u r t h e r d i v id id e d i n to to s p e c ia ia l it it y s e c t io io n s . Finishes Finishes are Division Division 9, and pa int and p ro te ct iv e c o at in g s a re Se ct io n 09 90 0. Ea ch section section is su bd ivided into the follow follow ing basic p a rt s:
P a rt 1 : G e ner a l .—Includes cost, references, su bm ittals, ittals, qu ality ality assura nce, d elivery elivery , storage, storage, han d ling, ling, and restr ictions. ictions.
—I n c l u d e s r e q u i r e m e n t s P a rt 2: P ro d uc t . —I for materials to be used In c lu lu d e s m o d e o f P a rt 3 : Exec ut i o n . — In construc tion, test test meth od s, acceptance criteria, and repair
10. Reclamation Reclamation Coating Specificati Specifications.— ons.— The Techni cal Service Center (TSC) (TSC) in Denv er m aintains CSI guid eline eline coating specifications. specifications. The gu ideline coating sp ecifications ecifications are the b a s is fo r s p e c ific p r o ject je ct r e q u i r em e n t s a n d a r e b a se d o n h ist o r ica l R e cla m a ti o n st r u ct u r e s. The gu ideline specificati specification on s con con tain i n s t r u c t io io n a l n o t e s a n d f o o t no no t e s t o a i d t h e s p e c if if ic ic a t io io n w r i t e r i n p r e p a r i n g t h e specificatio specification n s to m eet sp ecific ecific project project r e q u i r e m e n t s . T h e g u i d e li li n e co co a t i n g specifications specifications are av ailable on Reclamation ’s i n tr tr a n e t w e b s it it e : < h tt tt p : / / in t r a .u .u s b r .g .g o v > . Reclam Reclam ation u ses the follow follow ing speciality s e ct ct i o ns ns f o r c o a t in in g s a n d h a z a r d o u s b a s e d p ai n ts : —C o a t i n g s f o r n e w m e t a l l ic ic Sec t io n 0 99 02 . —C sub strates that includ includ e: steel, cast or d u ctile ctile i r o n ; g a lv lv a n i z e d , a lu lu m i n u m ; b r a s s ; b r o n z e ; o r copper Sec t io n 0 99 08 .—Maintenance coatings for p r e v io u s l y co a t e d m e t a lli c s u b s t r a t es th a t includ e: steel, cast or du ctile iron; galvan ized, a l u m i n u m ; br br a s s ; b r o n z e ; o r c o p p e r Se ct io n 0 99 80 .—Coatings for concrete and masonry substrates
i n g a n d d i sp sp o s in in g Se ct io n 1 32 83 .— H a n d l in of paint containin g heav y m etals (i.e., (i.e., chrom ate, lead, etc. . .) .)
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Guide to Protective Protective Coatings: Coatings: Inspection and Maintenance cl u d e s t h e (a) Part 1: General.— P a r t 1 i n cl
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S u r fa f a ce ce p r ep e p a ra r a ti t i o n m e t ho ho d s
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A pp p p li l i c a ti ti o n eq e q ui u i p m e nt nt
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C oa o a t in i n g a p p l ic ic at a t io io n r eq e q u i re r e m en en t s
following general outline: •
C os o s t p ro r o v is i s iio o ns n s fo f o r e it it he h e r l um um p s u m o r b i d i t e m
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R ef ef e r en e n ccee s fo fo r in in d u s tr t r ia ia l s ttaa n d a rd rd s use d in the s p ecificati ecification on section
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I n sp sp e ct ct io io n m eett h od od s a n d a cc cc e p ta t a n ce ce criteria
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S u b m i tt t t al a ls ar ar e r eq e q u i re r e d to t o en e n s u re r e th th e contractor is supp lying the spec ified fied m aterials. The follow follow ing subm ittals are essential:
•
R e p ai a i r of o f d a m ag a g eed d a n d n on on a cc c c e p t a bl bl e coated areas
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C oa o a ti t i ng n g t a b u la l a ti t io ns n s a n d c at a t eg e g or o r ie ie s (s (s eeee following following section)
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C o l o r s c h ed ed u le le
"
"
"
M a n u f a c t u r e r ’s ’s p r o d u c t d a t a a n d application sheets Ma nu facturer’s certifi certification cation of comp lian lian ce, stating that m aterials w e r e m a n u f a ct ct u r e d i n a cc cc o rd rd a n c e w i t h q u a l it it y a s su su r a n c e a n d q u a l i t y p ro g ra m s t o in cl u d e b at ch nu m bers, quantity, and color P u r c h a s e or or d e r s , e n s u r i n g t h a t t h e c o n t r a c t o r u s in in g a p p r o v e d m a t e r i a l s t o i n c lu lu d e b a t c h n u m b e r s , q u a n t i t y , a n d c o lo lo r
11. Coating Tabulations Tabulations and Categories.— T h e f o r m a t o f t h e c o a t in in g t a b u l a t io io n s a n d categories in the CSI specificati specifications ons will be s im im i la la r t o t h e o l d n a r r a t i v e p a r a g r a p h f o r m a t . T h e c o a t in in g t a b u l a t i o n s a n d c a t e g o r ie ie s c h a n g e o v e r t i m e b e c a u s e o f l o w e r V O C r e g u l a t i o n s, s, l e a d - a n d c h r o m a t e - f r e e r e q u ir ir e m e n t s , n e w c o a t in in g t e c h n o l o g y d e v e l o p m e n t s , a n d o t h e r factors. The following following sections describe the t a b u l a t i o n s a n d c a t e go go r i e s .
(a) Coating Tabulations.— The coating •
Q u al al i t y as as su su ra ra n ce
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D el e l i v e r y, y , s t o r a ge g e , a n d h an a n d l in in g
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E n v i ro ro n m e n t a l r e st st r ic ic ti ti on on s fo fo r s u rrff a c e p r e p a r a t io n a n d a p p lic li c a tio n
t a b u l a t i o n s a r e b a s e d o n R e c l a m a t i o n ’s ’s h i s t o r ic ic a l e xp xp e r i e n c e w i t h c o a t in in g m e t a lw lw o r k i te te m s , s e r v i ce ce e x p o s u r e , a n d m a t e r i al al s u s e d i n d a m s a n d w a t e r co co n v e y a n c e p r o je je c t s. s. T h e t a b u l a t i o n s a r e i n t h e f o l lo lo w i n g t a b l e f or or m a t : •
I te te m s to to be b e co co aatt ed e d a r e i de d e n t if if ie ie d .
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C oa o a t in i n g m a te t e ri r i al a l s ar ar e id id e n t if ifi ed e d i n t he he f ir ir s t co co l u m n b y a n a l p h a n u m e r i c l a b e l f o r a m a n u f a c t u r e r ’s ’s b r a n d n a m e o r a F e d e r a l / m i l it it a r y s p e c if if ic ic a t i o n n u m b e r . Several equivalent coating materials m a y b e l is is t e d w i t h in in t h e s a m e m a t e r ia ia l o p t i o n n u m b e r . M o r e th th a n o n e c o a t in in g m a t e r i a l o p t i o n m a y b e l i s t e d in the tabu lation. For smal l jobs, the c o lo lo r m a y b e s p e ci ci fi fi e d i n t h i s co co l u m n .
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N u m b er e r o f c o at at s (p ri ri m mee r , i n t e r m e d i a t e , a n d t o p c o a t ) , t h i c kn kn e s s
lu d e s t h e (b) Part 2: Products.— P a r t 2 i n c lu f o ll ll o w i n g m a t e r i a l r e q u i r e m e n t s o u t l i n e : • • •
Ab rasives M IO C o a t in g s
cl u d e s t h e (c) Pa rt 3: E xecution.— P a r t 3 i n cl f o ll ll o w i n g o u t l in in e r e q u i r e m e n t s t o c o m p l e t e work: •
•
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P ro r o t ec e c t io i o n a n d r ep ep a i r of e x xii s t in in g surfaces E m b ed ed d e d m e ta ta lw l w o rk rk in i n c on on ccrr et et e
Specifications o f e a ch ch a p p l i ed ed c oa oa t , a n d t o t a l d r y f i lm lm thickness (DFT) of the the coating system a r e id id e n t i fi fi e d i n t h e s e co co n d c ol ol u m n . •
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following a re (a) Product Data Data Sheet.— The following the most common items on the prod uct data sheets:
S u rf r f ac a c e p re r e pa p a ra r a ti t i o n m e th t h od o d s ar ar e i d e n t i fi fi e d b y l e t t e r or or a l p h a n u m e r i c l a b e l i n t h e t h ir ir d c o l u m n a n d a r e d e f i n e d i n t h e e x e c u t io io n p a r t f o r surface preparation.
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G en e n eerr ic i c c h eem m i ca ca l c o aatt in in g n a m e (acrylic, (acrylic, alkyd , epo xy, pol yure than e)
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T y p ic i c a l u s es es , s uc uc h as as o on n b r id i d g es es , p i p e s , o r w a t er t a n k s
I n s tr t r u c ti t io n a l n ot o t es e s , i f s pe p e c if if i e d , ar ar e l o ca ca t e d a t e i t h e r t a b l e f ro ro n t o r e n d .
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S e r v ic ic e e x p os o s u re r e fo f o r at a t m o sp s p h e ri ric, b u r ia l, im m er si o n (f re sh w a te r or sa lt w a t e r ) , an an d c h e m i c a l r e s is is ta ta n c e
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C ol o l or o r a n d gl g l os os s a v vaa il i l ab a b il i li ty ty
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P h y si si ca ca l o r t ec e c h n ic ic al al p r o p e r ti ti es es , s u c h a s w e i g h t p e r g a l l o n , s o li li d s b y volum e, VOC content, pigment ad d itives, itives, flas flashp hp oint, and service t e m p e r a t u r e r e s i st st a n c e
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R e co co m m en en d ed e d d r y o r w et e t fi fi l m thickness
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T he h e o re r e t ic ic a l c o ve v e r ag a g e r a te t e pe p e r g a ll l lo n
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M ix i x ra r a ti ti o ( if if m u lt l t i c o m p o n en e n t s ys y s t em em ) , p ot li fe, fe , a n d in d u ct io n or sw ea t- in ti m e ( e la la p s e d t i m e i n t e r v a l t o a l l ow ow t h e chem ical reaction to begin for m u l t i co co m p o n e n t m a t e r i a l s b ef ef o r e application)
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D r y , r e c oa o a t, t, c u r i n g , a n d f u ll l l c u r e t im im e p e r i o d s a t t e m p e ra t u r e a n d h u m i d i t y ranges
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P e rf rf o rm rm a n c e te te sstt re r e s ul ul t s (a c ce ce l er er a te te d A S T M t e s t s th th a t m a y o r m a y n o t b e listed)
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Sh el f li fe
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S a fe fe ty t y p re re ca c a ut u t io io ns ns
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S h ip ip p i n g d at ata
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W a r r an a n t y a n d l im im i t a ti tio n s o f li ab a b i li li ty ty
(b) Coating Categories.— The coating categories specify, by alph anu m eric labels, labels, the m a n u f a c tu tu r e r ’ s b r a n d n a m e o r t h e F ed ed e r a l o r m ilitary ilitary specificati specification on n um ber of th e ccoating oating ma terial listed listed in the tabula tion tion s. Th e c a t e g o ri ri e s a r e su su b d i v i d e d a c c o r d i n g t o t h e follow follow ing th ree essential characteristics: characteristics: .—List the gen eric chemical C o m p o s i t i o n .—List c o a t in in g n a m e —W e i g h t p e r P hy si ca l c ha ra ct er is t ic s . —W g a l lo lo n , V O C c o n t e n t , m i n i m u m a p p l ic ic a t io io n t e m p e r a t u r e , c u r i n g t i m e s a t s p e c i fi fi c t e m p e r a t u r e a n d h u m i d i ty ty , e tc tc . P er fo rm an ce re qu i re me nt s .— Accelerated ASTM testing and accep tance criteria criteria
12. Manufacturer's Product Data and Applica tion Sheets.— She ets.— Reclamation specifications specifications requ ire the subm ittal of the c o a t in in g m a n u f a ct ct u r e r ’s ’s p r o d u c t d a t a (sometime s called called techn ical d ata) and ap plication plication sheets. These shee ts specify specify t h e m a n u f a ct ct u r e r ’s ’s i n s t r u c t io io n s a n d r e co co m m e n d a t i o n s . T h e m a n u f ac ac t u r e r ' s i n s t r u c t io io n s a n d r e c o m m e n d a t i o n s h a v e be b e c o m e s p e c ific if ic a t io n r e q u i r e m e n t s , u n l e ss t h e specifications specifications are mor e restrictive. Prod uct d a t a a n d a p p l ic ic a t io io n s h e e t s s h o u l d b e k e p t f or or f u t u r e r e fe fe r e n c e t o v e r i fy fy t h e m a t e r i a l t y p e a p p l ie ie d . T h e p r o d u c t d a t a a n d a p p l i c a ti ti o n sheets vary in content and format from m a n u f a c tu tu r e r t o m a n u f a c tu tu r e . S om om e m a n u f a ct ct u r e r s co co m b i n e p r o d u c t d a t a a n d a p p l ic ic a t io io n i n t o o n e s he he e t . H o w e v e r , t h e s h e e t s p r o v i d e u s e f u l in in f o r m a t i o n f o r t h e specific specific m aterial.
follow ing are the (b) Application Sheet.— The follow m o s t c o m m o n i t e m s o n t h e a p p l ic ic a t io io n s h e e t :
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Guide to Protective Protective Coatings: Coatings: Inspection and Maintenance •
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S u b st st r at a t e ty t y p e s t h a t a r e c o m p a ti t i b le le w ith the coating m aterial (e.g. (e.g.,, a l u m i n u m , c on on c r e t e , g a l v a n i ze ze d , s te te e l , cast iron, or existing existing coated surfaces)
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S u r fa fa c e p r ep ep a r a ti ti o n m et e t h od od , n or o r m a ll l ly l is is t ed ed a s a m i n i m u m
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T h i n n e r p r od od u c t n a m e an a n d a m ou o u nt n t to to be b e a d d e d
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P ot o t -l - l i fe fe -t - t im im e o f m u l ti t ic o om m p o n e nt nt c o a t in in g m a t e r i a l a t v a r i o u s t e m p e r a t u r e a n d h u m i d i t y r an an g e s
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L o we w e r a n d u p p e r t e mp m p e ra r a t u re re a n d h u m i d i t y r a n g e r e s tr tr i ct ct i o n s d u r i n g application
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M o st s t ma m a n u fa f a ct ct u r er er ’s ’s s ttaa te t e th th a t t h e c o a t in in g i s t o b e a p p l ie ie d o n l y w h e n t h e substrate temp erature is 5 degrees F, minimum, above the dew point
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D ry r y i ng n g , r e co co aatt , a n d cu c u r in in g ti t i me me s a t v a r i ou ou s t e m p e r a t u r e a n d h u m i d i t y ranges
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A p p l ic ic a t io io n m e t h o d: d : b r u sh s h , r o ll ll e r , conven tional airless airless spray , or airless airless spray. May include specific e q u i p m e n t a t r e c o m m e n d e d p r e ss ss u r e s , h o s e d i am am e t e r s iz iz e s , sp sp r a y g u n , n o z z l e tip sizes , etc.
13. Addendums and Modifications.— Modifications.— Specifications Specifications are som etimes chang ed to alter d esign esign s, correct errors, or red ress omissions. T h e fo fo l lo lo w i n g t w o g e n e r a l m e t h o d s a r e u s e d t o revise specifi specifications: cations: (1) ad d end um s (also (also c a ll ll e d a m e n d m e n t s ) a r e w r i t t e n p a g e i n s e r t s tha t change p art(s) of the specification specification before b id d in g o c cu r ; a n d (2) m o d i fic a t io n s a r e w r i t t e n p a g e i n s e r t s t h a t m o d i fy fy p a r t ( s) s) o f t he he specification specification after after the contract is aw ard ed . M o d i fi fi ca ca t i o n s c a n i n c u r c o st st a d ju s t m e n t s t o t h e c o n t r a c t a n d a r e o f t en en c a l l ed ed c h a n g e o r d e r s .
Chapter IV Inspector's Role The coating inspector ensures that: (1) (1) the w o r k i s a c c o m p l i sh sh e d i n a t i m e l y m a n n e r i n accorda nce w ith the sp ecificati ecifications; ons; (2) (2) w ork a c ti ti v i ti ti e s a r e d o c u m e n t e d ; a n d ( 3) 3) w o r k i s p e r f o r m e d s a f e ly. ly . T h e c o a t in g i n s p e c t o r a t t h e job si t e is e i th e r t h e c o n t r a c t ing in g o f fi cer ce r ’s or t h e field engineer’s representative. T h e i n sp sp e c t o r sh sh o u l d n o t v e r b a l l y c h a n g e t h e requirem ents or require more rigid r e q u i r e m e n t s o n t h e co co n t r a c t o r th th a n w e r e originally specified specified . The insp ector shou ld contact his sup ervisor for resolution if the s p e c if if ic ic a t io io n s a r e i n a d e q u a t e . C o n t r a c t o r s m a y r e q u e s t a v a r i a n t f r o m s p e c if ic ic a t io io n s t h a t m a y or may not be significant. Regardl ess of varian t significa significan n ce, the insp ector sh sh ou ld i n f or or m h i s s u p e r v i s o r o f a n y r e q u e s t e d changes . If a coating coating ap plicator is not follow follow ing the specifications, specifications, the inspector s h o u l d n o t co co n f r o n t t h e a p p l ic ic a to to r . I n st st e a d , h e s h o u l d a s k t h e c o a t in in g c o n t r a c t o r s u p e r v i s o r t o d e t e r m i n e w h y t h e s p e c if if ic ic a t io io n s a r e n o t b e in in g f o ll ll o w e d . I n s o m e c a s e s, s, a d e v i a t io io n m a y h a v e b e e n a l lo w e d o r t h e c o a ti n g c o n t r a c t o r s u p e r v i s o r m a y n e e d t o c or or r e c t h i s ow ow n w orker’s p ractices. ractices.
14. Primary Responsibilities.— The follow follow ing
follow ing is 15. Daily Responsibilities.— The follow a p artial list list of daily insp ection resp onsibilities: onsibilities:
(a) Preparatory.— •
E n s u r e s p e ci ci f i ca ca t io io n s c o n t a in in al al l a d d e n d u m s a n d m o d i fi fi ca ca t io io n s
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E ns n s ur u r e a ll ll sp s p e ci c if i c a t io io n s ub u b m i tt tt a l r e q u i r e m e n ts ts a r e m e t
(b) Presurface Preparation.— •
E ns n s ur u r e w ea e a th t h eerr co co nd n d i ti t i o ns n s ar ar e c o n d u c iv iv e t o b l a s t in in g o p e r a t i o n s
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D et e t er e r m in i n e p r eb e b la l a sstt s ur u r fa f a ce ce co c o nd n d i t io io n for rust grade
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E ns n s ur u r e t ha h a t t he h e su s u rf r f ac a c e is is fr fr ee e e of of irregu larities larities (weld spatter , slag slag burrs, s h a r p e d g e s , p i t s , l a m i n a t io io n s , o r o t h e r objectionable objectionable irregu larities) larities)
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E ns ns u re r e t ha h a t a b ra ra si s i ve v e s m e et et s p e c if if ic ic a t io io n r e q u i r e m e n t s a n d a r e w i t h i n c o nt nt a m i n a t i o n li li m i t s
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E ns n s ur u r e t he h e a ir ir c om om p r e ss ss or o r is is fr fr ee ee o f m oisture and oil contamination
are prim ary resp onsibilities onsibilities of th e insp insp ector: •
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•
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V e r if if y in in w r i ti ti n g th t h a t c o a ti ti n g w o r k is is be b e i n g p e r f o r m e d i n a c co r d a n c e w i t h the specifications specifications
(c) Postsurface Postsurface Preparation.— Preparation.— •
M o n it i t or or w o rk rk a c ti ti vi v i ty ty on o n a d a il i l y b aass iiss , i n c lu lu d i n g d e v i a t i on on s f r o m t h e specifications
E ns n s ur ur e t he h e su s u rf r f ac a c e p re r e p ar a r at a t io io n m e t h o d m e e t s s p e c if if ic ic a t io io n s requirements
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E n su s u r e t h e s u r fa fa c e ( an an c h or or ) p r of of i l e m e e t s s p e c i fi fi ca ca t i o n s r e q u i r e m e n t s
R ep e p o rt rt a n d r ec ec o orr d d e f ic ic ie ie n ci c ie s t o th th e field field engi neer for resolution
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E ns n s ur u r e th t h e su su rf r f ac a c e is is fr fr ee ee o f c o n ta ta m i n a n t s a n d m e e t s c l e a n li li n e ss ss specifications requirements
E n su s u r e w o r k is is c o n d u ct ct e d in i n a s af a fe manner
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Guide to Protective Protective Coatings: Coatings: Inspection and Maintenance
(d) Precoating Application.— •
E n su s u r e a ll ll c o a ti t in g m a t er er ia ia ls ls a re re approved
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C h ec e c k s to to ra r a ge g e ar a r e a f or o r pr pr o p er er e n v i r o n m e n t a l a n d s a f et et y requirements
•
E ns n s ur ur e e n nv v ir i r on o n m e n ta t a l co nd n d i ti t i o ns ns ( a m b i e n t a n d s u r f a c e te te m p e r a t u r e s , h u m i d i ty ty , a n d d e w p o i n t ) m e e t specifications requirements
•
E n su s u r e m i xi xi ng n g a n d th t h in i n n in i n g m e et et m a n u f a ct ct u r e r ’s ’s re re q u i r e m e n t s
resp onsible review ing office office is listed listed in the r e q u i r e d s u b m i tt tt a l n u m b e r ( RS RS N ) t a b l e i n Section 01330 01330 (Su (Su bm ittals) of th th e CSI specifications. The coatin coatin g inspector is not u sually r e s p o n s i b l e f o r ap ap p r o v i n g o r d i sa sa p p r o v i n g c o n t r a c t o r s u b m i t t e d m a t e r i a l. l. H o w e v e r , t h e i n s p e c t o r s h o u l d t r a c k c on on t r a c t o r a n d R e cl cl a m a t i o n c o r r e s p o n d e n c e t o e n s u r e t h a t o n l y a p p r o v e d m a t e r ia ia l s a r e u s e d o n t h e job s i t e. If the TSC in the Den ver Office is the resp onsible specification specification rev iewing office, office, it it w i ll ll p r o v i d e a c o n t r a c t o r s u b m i t t a l w i t h o n e o f t h e f o l lo lo w i n g r e s p o n s e s :
(e) Coating Application.— •
•
•
E n su s u r e a p p li l ic at a t io io n m e t ho h o d s m e et et m a n u f a c t u r e r ’s ’s re re q u i r e m e n t s E ns n s ur u r e i n t er e r m e d ia ia t e co a t a n d t o pc p c o at at a p p l ic ic at at i o n s a r e w i th th i n r e co co a t t i m e i n te te r v a l fo fo r t e m p e r at a t u r e a n d h u m i d it it y ranges and that they meet the specifications specifications or the man ufactu rer’s requirements C h ec ec k a mb m b ie i e n t t e m pe p e r at at u r e a n d h u m i d it i t y d u r i n g c u r in in g p e r i o d
— In d ic a t es m a t e r ia l c a n b e A p p ro v ed . ed . — p u r c h a s e d a n d a p p l ied ie d . . —Indicates the C o n d it it i o n a l l y a p p r o v e d .—Indicates m aterial selecti selection on is accep accep table and the m a t e r ia ia l m a y b e p u r c h a s e d ; h o w e v e r , t h e sub m ittal is incom plete or is m issing issing d o c u m e n t a t i o n . R e su su b m i t t a l o f i n c o m p l e t e o r m i s s in in g d o c u m e n t a t i o n is is r e q u i r e d . C o n d i ti ti o n a l ap ap p r o v a l d o e s n o t i m p l y a c ce ce p t a n c e fo r m a t e r i a l a p p l ic ic a t io io n . lected N o t a p p ro v ed .—Indicates the se lected m a t e r ia ia l is is n o t a p p r o v e d f o r a p p l i ca ca t i o n .
(f) Postcoating Application.— •
E ns ns u r e t h e d r y f il i lm t hi h i ck c k ne n e ssss m e et et s specification requirements
•
I ns n s pe p e ct c t d r y f il il m f or o r h ol o l id id a y (p ( p in i n h ol o l e) e) defects
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E ns n s u re r e th t h aatt d e fe fe ct ct iv iv e , d a m a g ed ed , a n nd d d e f i ci ci e n t a r e a s a r e r e p a i r e d t o m e e t specification requirements.
T h e in in s p e c t o r s h o u l d c h e c k b a t c h n u m b e r s o n m a t e r i a l c o n t a i n e r s a g a i ns ns t t h e a p p r o v a l l e tt tt e r ba b a t c h n u m b e rs f or m a t e ri a l s th a t a r ri ve o n t h e job jo b s it e . C o n t a in e r s w it h b a t ch n u m b e r s th a t d o n o t c o r r e s p on o n d t o t h e a p p r o v e d m a t e r ia ia l b a tc h n u m b er s s h o u ld b e re m o v ed fr om t h e job s i t e. or s h o u l d 17. Documentation.— T h e i n s p e c t or a c q u i r e t h e f ol ol lo lo w i n g d o c u m e n t s :
F o r a m o r e c o m p r e h e n s i v e l is is t o f respon sibilities, sibilities, see ap pen d ix C. C.
•
S p e c if if ic ic at a t io io ns n s th th a t i n ccll ud u d e a d d e nd nd u m s a n d m o d i fi ca ca t i o n s
16. Material Approval.— C o n t r a c t o r
•
T he h e m a nu n u fa f a ct ct ur u r er e r ’s ’s p ro r o d u ct c t d at a t a, a, ap p lication, lication, and Material Safety Data Data Sheet (MSDS)
s u b m i tt tt e d c oa oa t i n g m a t e r i al al s a r e n o r m a l ly ly r e v i e w e d b y t h e R e c l a m a t i o n o f fi fi ce ce t h a t e i t h e r p r e p a r e d o r i s su e d t h e s p e c if ica ic a t io n s . Th e
16
Inspector's Role •
•
R ef e f e re r e n ce c e st s t an a n d a rd rd s r ef e f er e r re re d t o i n t h e specificati specification on s that r elate to th e field field inspection R e fe fe r en e n c e s ttaa n d a r d s a r e d i sc sc u s se sed i n m o r e d e t a i l f or or t h e p e r t in in e n t i n sp sp e c t io io n m e t h o d i n o t h e r c h a p t e r s. s. A p p e n d i x D l is is t s r ef ef e r e n ce ce s t a n d a r d s c it it e d i n t h i s d o c u m e n t
18. Instruments, Gauges, Gauges, and and Tools.—Th e i n s p e c t o r s h o u l d a c q u i r e t h e eq eq u i p m e n t , i n s t r u m e n t s , a n d i n s t r u c t io io n a l m a n u a l s n e c e ss ss a r y t o p e r f o r m t h e i n s p e c t io io n w o r k . Spare ba tteries sh sh ou ld be av ailable ailable if electron electron ic instrum ents are used. The types of i n s t r u m e n t s w i ll ll b e d i s cu cu s s ed ed i n t h e f o l lo lo w i n g c h a p t e r s a n d a r e l is is t e d i n a p p e n d i x E . (a) Conflicts.— A t t i m e s , t h e r e a r e d i s a g r e e m e n t s b e t w e e n t h e co co n t r a c t o r a n d t h e i n s p e c t o r o v e r in in s t r u m e n t r e a d i n g s s u c h a s surface anch or pr ofiles ofiles or d ry film film thicknesses. T h e r e m a y b e r e a s o n a b l e e x p l a n a t i on on s f o r s u c h d iscrepa iscrepa ncies. Th ese discrepan cies shou ld be i n v e s ti ti g a t e d t o a v o i d f u t u r e c o n f l ic ic t s a n d t o d e v e l o p a w o r k i n g r e la la t i o n sh sh i p w i t h t he he contra ctor. Th e following following are some p o ss i bi li t ie s f or i n st r u m e n t d i sa g re e m e n t s: •
•
T he h e tw t w o p a r t ie ie s a re r e n ot o t us u s iin n g t he h e sa sa m mee t y p e o f i n s t ru ru m e n t s e t s : "
One instrument may be malfunctioning
"
O n e i n st st r u m e n t m a y b e o u t o f calibration
T he h e t wo wo p a rt r t ie ie s ar a r e u s in in g t he h e sa sa m e t y p e o f in in s t r u m e n t s b u t : in g d i ff ff e r e n t " T h e y a r e u s in p r o c e d u r e s "
They are taking readings at differen t location location s
"
O n e i n s tr tr u m e n t m a y b e o u t o f calibration
19. Substrate Inspection.— T h e i n s p e c t o r s h o u l d i n s p e c t e d t h e s u b s t r a t e s u r f a ce ce b e f o r e s u r f a c e pr pr e p a r a t i on on . F e r r ou ou s s u b s tr tr a t e s w i t h l o ca ca l iz iz e d r u s t o r m i ll ll s c a le le a r e m o r e p r o n e t o p r em a tu r e c o a ti n g fa il u r e. Ru st an d m il l sca sc a le areas should be inspected more thorou ghly for clean clean liness after su su rface rface pr epa ration. If mill scale is noted and abrasive blasting is not specified specified , notify the field field en gineer becau se a b r a s i v e b l a s ti ti n g i s r e q u i r e d . F or or m a in in t e n a n c e c o a t in in g w o r k w h e r e o v e r c o a t i n g i s s p e c if if ie ie d , t h e e x is is t in in g c o a t i n g m a t e r i a l s h o u l d b e i n s p e c t e d f o r l o o se se c o a t i n g s b y s c r a p i n g w i t h a s h a r p e n e d p u t t y k n i fe fe . O v e r c o a t in in g l oo oo s e l y ad herin g existing existing coating w ill result in p r e m a t u r e f a il u r e . F o r i te te m s c o a te te d i n a s h o p , th th e c o a t in in g s s h o u l d b e in s p e ct e d a n d id e n t ifi e d fo r d a m a g e a n d failed failed coating ar eas that w ill requ ire rep air either befor e or after installation.
20. Coating Inspection Checklist Sheet.— Reclam Reclam ation sp ecificati ecification on coating tabu lations (see chap ter III, subsection 11) 11) ident ify ify th e items to be coated , coating coating m aterials, the the DFTs, a n d t h e s u r f ac ac e p r e p a r a t i on on m e t h o d s ; h o w e v e r , t h e i n s p e c t o r ma ma y w i s h t o e x p a n d o n t h e c o a t in in g t a b u l a t i on on s b y c r ea ea t i n g a c o a t i n g inspection checklist u niqu e to th e job. job. Since Since specificati specification on coating tabu lation lation s can can iden tify tify s e v e r a l it it e m s t o b e c o a t e d w i th th i n a s i n g l e t a b u l a t i o n , a n i n s p e c t io io n s h e e t c a n p r o v i d e f o r t h e i n d i v i d u a l co co a t i n g o p e r a t i o n s a n d f o r t h e c o m p l e t e d i n s p e c t io io n f o r a s in in g l e i t e m t o b e c o a t e d , s u c h a s a p i p e l i n e i n t e r io io r o r a r a d i a l g a t e . T h e ch ch e c k l is is t ca ca n b e c o m e a p e r m e a n t r e c o r d o f t h e jo jo b . A c h e c k li li s t e x a m p l e a p p e a r s i n a p p e n d i x F. F.
21. Precoating Conference.— Reclamation coating specifications specifications d o not requ ire a p r e co a ti n g co n fe r e n ce w it h th e co n tr a ct o r . H o w e v e r , a m e e t i n g w i t h t h e c o n t r a c t o r to to d i s c u s s c o a t in in g - r e l a t ed ed i s su su e s w o u l d b e helpful . A preco ating confere nce will allow t h e c on on t r a c t o r t o k n o w w h a t i s e x p e c t e d a n d t o o u t l in in e t h e w o r k p r o g r a m . T h i s m e e t in in g s h o u l d e s ta ta b l i sh sh a w o r k i n g r e l a t io io n s h i p be t w e en t h e co n t ra ct or a n d R ec la m at io n . Th e follow follow ing are p ossible items items for d iscu iscu ssion at the meeting:
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Guide to Protective Protective Coatings: Coatings: Inspection and Maintenance •
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T he h e c o nt n t ra r a c to to r ’s ’s jo jo bb - s pe pe c if if ic ic w o r k er er h e a l t h a n d s a fe fe t y p l a n ( a s u b m i t t e d w r i t t e n p l a n i s r e q u i r e d f o r le le a d o r o t h e r h a z a r d o u s m a t e r ia ia l r e m o v a l a n d disposal)
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T he h e m e th t h od o d o f d u st s t co co ll ll e ct ct io io n an an d disposal of used abrasives
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U nf n f av av or o r ab ab l e w e at at he h e r r el el at a t ed ed t o p r e p a r e d s u r f a ce s , a p p lie li e d c o a tin ti n g s , o r curing
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T h e p l a n f o r co co a t in in g in i n a cc cc e s si si b le l e a re re a s
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I n sp s p e ct ct io io n m e t ho h o d s a nd n d t he h e nu nu m b e r o f measurements
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T he he ty t y p e s of of in in sp s p e c ti t io n in i n st s t ru ru m e n t s t o be b e u s e d
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T he h e NA N A C E/ E / S S P C r ef e fe re r e nc n c e st st an a n da d a rd rd s t h a t a r e s p e c if if ie ie d , t h e v i s u a l s t a n d a r d s t o b e m e t , an an d t h e a c c ep ep t a n c e cr cr i t e r ia ia
T he he i ns n s p e ct c t or o r ’s ’s a cc c ce ssss a nd nd s aaff et et y T h e co co n tr t r ac a c t o r’ r’s p r o p os os e d o p er er a ti ti o n , i n c lu lu d i n g e qu q u i p m e n t a n d p e r s o nn nn e l T he h e co co n tr t r a ct ct o r’ r ’s w o rk r k i ng n g ho h o u rs rs T h e m a te t e r ia ia l s to to r ag a g e a r ea ea , in in ccll u d i n g t e m p e r a t u r e , v e n t i la la t i o n , a n d s e c u r i t y T he h e aap p p r ov o v eed d s u rf r f ac a c e pr p r e p ar a r at a t io io n m e t h o d s , a b r a s i v e s , c oa oa t i n g m a t e r i a l s, s, a p p l ic ic a t io io n m e t h o d s , a n d c u r i n g t i m e s
Chapter V Material Storage, Containers, and Shelf Life Coa ting ma terials arrive arrive on th e jobsite jobsite before a p p l ic ic a ti ti o n b e g i n s , a n d t h e y r e q u i r e st st o r a g e . M a n u f a c tu tu r e r s r e c o m m e n d s p e c if if ic ic p r o v i s io io n s f o r st st o r a g e t o p r e v e n t c o a ti ti n g d e t e r io io r a t i o n . C o a t i n g m a t e r i a ls ls m u s t b e u s e d w i th th i n a s p e c if if ie ie d t i m e f r o m m a n u f a ct ct u r e o r s h i p m e n t .
a n d h o t in i n s u m m e r a n d h a v e l im i m i t ed ed v e n t i la la t i o n . C o a t i n g m a t e r i a l s s h o u l d b e s t o r e d i n c li li m a t e c o n t r o l le le d e n v i r o n m e n t s . The followi followi ng are generally accepted regu lations for storing storing coating m aterials:
Indoor storage.— N o m or e t h a n 25 g a ll on s ia l s sh sh o u l d b e 22. Storage.— C o a t i n g m a t e r ia s t o r e d i n a c o v e r e d , w e l ll- v e n t i la la t e d a r e a a w a y f r o m s p a r k s , f la la m e s, s, a n d d i r e c t su su n l ig ig h t . M a n y c o a t in in g s r e q u i r e a l im im i t e d t e m p e r a t u r e range for proper storage. Cold storage may requ ire a coating coating to be excessively excessively thinn ed for ap plication, resulting resulting in low low s olid olid s conte conte nt and a less-than-intend less-than-intend ed DFT. At or below f r e e z in in g t e m p e r a t u r e s , c o a t in in g s ( s u c h a s w a t e r b a s e d m a t e r ia ls ) ca c a n d e g r a d e t o th e p o in t t h a t t h e y a r e u n u s a b l e . M a t e r i a l s in c o ld ld s t o r a g e s h o u l d b e m o v e d t o a h e a t e d a r e a b e fo fo r e a p p l ic ic a t io io n . A t h i g h t e m p e r a t u r e s , a m a t e r i a l s u c h a s s o l v e n t -b -b a s e d c o a t in in g m a y g e l o r b e co m e fla m m a b le o r e xp lo s iv e . T h e st o r a g e s it it e s h o u ld l d b e m o n i t o re re d u s in in g a h i g h / l ow ow thermometer. C o a t i n g m a t e r ia ia l s sh sh o u l d b e s t o r e d t o g e t h e r b y t h e s a m e b a t ch ch o r l o t n u m b e r s . T w o c o m p o n e n t c o a t i n g sy sy s t e m s s h o u l d b e s t o r e d c lo lo s e t o g e t h e r b u t b e d i s t in in g u i s h a b l e fr fr o m o n e a n o t h e r . F o r st st o r a g e o f s e v e r a l m o n t h s o r l o n g e r , co co n t a i n e r s s h o u l d b e i n v e r t e d o n a m o n t h l y b a s is is t o a v o i d e x ce ce s s iv iv e s e t t l in in g a n d for ease ease of futu re mixing. The oldest coating coating m a t e r i a l s sh sh o u l d b e u s e d f i r st st . S ol ol v e n t s a n d t h i n n e r s s h o u l d b e s t o r e d separat ely from from coating m aterials. Sepa ration o f s o lv lv e n t s a n d t h i n n e r s i s a sa f e t y c o n c er er n be b e c a u s e m a n y o f t h e s e m a t e r i a ls h a v e lo w e r f la la s h p o i n t t e m p e r a t u r e s th th a n m o s t c o a t in in g s , a n d t h e y p o s e a p o t e n t i a l f ir ir e h a z a r d . Contr actors will often often store coating m aterial at the jobsite jobsite in in trailers. Trailers w ith no heat ing, cooling, cooling, or ventilation ventilation system s are u nsu itable f o r s t or or a g e b e c a u s e t h e y b e c o m e c o l d i n w i n t e r
o u t s i d e o f a p p r o v e d c a b in in e t s i n a s in in g l e a r e a .
Outdoor storage.— N o m or e t h a n 1,1 00 g a l lo lo n s o f m a t e r ia ia l s g r o u p e d t o g e th th e r . N o m o r e t h a n 6 0 ga ga l l o n s i n i n d i v i d u a l c o n t ai ai n e r s . F o r fu fu r t h e r i n f o r m a t i o n o n t h e s t o r a g e o f f la la m m a b l e a n d c o m b u s t ib ib l e l i qu qu i d s , r e f e r t o t h e m a n u f a c tu tu r e r ' s M SD SD S a n d “ R e cl cl a m a t i o n S a fe fe t y a n d H e a l t h St St a n d a r d s .” .” ar g e l y i n 23. Containers.—C o n t a i n e r s v a r y l ar v o lu l u m e a n d c o m m o n l y r a n g e f ro ro m 1 q u a r t t o 55 gallons. Because of app lication lication equ ipm ent l im im i t a t i o n s , t h e m o s t c o m m o n c o n t a i n e r s o n a job jo b sit e w ill il l b e ei th e r 1-g a llo n o r 5-g a llo n p a ils . S in in g l e c o m p o n e n t m a t e r i a l s a r e s h i p p e d i n o n e c o n ta t a in in e r , a n d t w o o r m o r e c o m p o n e n t m a t e r i a l s a re re s h i p p e d i n s e p a r a t e c o n t a i n e r s , each of which has the capacity to hold the total c o m b i n ed ed v o l u m e . A n y c o n t a i n e r s t h a t a r e d a m a g e d , le le a k i n g , o r u n l a b e l e d s h o u l d b e r e je je c t ed ed a n d r e m o v e d from the job site.
24. Shelf Life.— Shelf Shelf life life is is th e length of time a f te te r m a n u f ac ac t u r e t h a t a c o a t in in g m a t e r i al al w i ll ll r e m a i n u s a b l e w h e n s t o r ed ed i n a n u n o p e n e d c o n t a in in e r , a cc cc o r d i n g t o t h e m a n u f a ct ct u r e r . Ma nu factu factu rers norm ally sp sp ecify ecify the shelf life life o f a c o a t in in g o n t h e c o n t a i n e r o r u s e a s p e c i a l c o d e o r b a r c o d e t h a t s p e c i fi fi e s t h e d a t e o f m a n u f a c tu tu r e o r t h e e x p i r a t io io n d a t e . F o r special cod cod es or bar codes , the insp ector may n e e d t o ca ca l l t h e m a n u f a ct ct u r e r t o r e a d t h e c o d e . In gene ral, m ost coatings have a shelf life life of b e t w e e n 6 a n d 12 m o n t h s a t a n o p t i m a l t e m p e r a t u r e , b u t t h i s w i ll ll v a r y w i t h
19
Guide to Protective Protective Coatings: Coatings: Inspection and Maintenance m anu factu factu rer and m aterial typ e. Shelf life life is n o t e d o n t h e m a n u f a ct ct u r e r ’s ’s p r o d u c t d a t a s h e e t . T h e in in s p e c t o r s h o u l d c h e c k t h e d a t e o f m a n u f a c t u r e o r t h e e x p i r a t io io n d a t e t o d e t e r m i n e t h a t t h e ex ex p i r a t i o n d a t e h a s n o t b e e n r e a c h e d . C o a t i n g m a t e r i a ls ls t h a t h a v e e x c ee ee d e d
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t h e s h e l f l if if e sh sh o u l d b e r e m o v e d f r o m t h e job si t e. C on se q u en ce s of e xc e ed in g th e s h el f life life include gelling, odor, chang es in viscosity, viscosity, f o r m a t i o n o f lu lu m p s , p i g m e n t s e t t le le m e n t , a n d c o lo lo r o r l iq iq u i d s e p a r a t i o n .
Chapter VI Surface Preparation T h e s e r v i ce ce l i fe fe o f a c o a t in in g d e p e n d s o n t h e de gree of surface preparation achieved as m u c h a s it it d e p e n d s o n m a t e r i a l s e le le c t io io n a n d ap p lication. lication. All coatin coatin g system system s w ill e v e n t u a l ly ly f a i l ; h o w e v e r , p r e m a t u r e f a il il u r e s a r e o f t en en t h e r e s u l t o f i n ad ad e q u a t e s u r fa fa c e p r e p a r a t i on . Ev e n s u r fa ce p r e p a r a t io n s t h a t achieve an accepta ble margi n of cleanliness cleanliness but l e a v e c on on t a m i n a n t s o n t h e s u r f a c e w i l l t en en d t o lessen the coating service life. life. Thu s, cleanliness cleanliness o f the su bstra te is an essential and i n t e g r a l co co m p o n e n t o f a c o a t in in g s y s t e m .
25. Surface Contaminants .—Surface c o n t a m i n a t i o n i s o n e o f th th e m o s t co co m m o n causes of coating failures. To achieve the m aximu m service life life of of a coating system , it it is e ss ss e n t i a l to to r e m o v e s u r f a c e c o n t a m i n a n t s .
(a) Types of Surface Surface Contaminants.— Th e f o ll ll o w i n g a r e t h e m o s t c o m m o n t y p e s o f s u r f a c e co co n t a m i n a n t s a n d t h e c o n s e q u e n c e s o f n o t r em e m o v i ng ng t h e m : is t h e c o r r o s io io n b y p r o d u c t Rust.— R u s t is (ferrou (ferrou s oxid oxid e) of steel and m ay be loose or m a y a d h e r e r e l a ti ti v e l y ti ti g h t l y t o t h e s u b s t r a t e . R u s t is is p o r o u s a n d m a y i n c lu lu d e m o i s t u r e , o x y g e n , a n d s o l u b l e s a lt lt s . R u s t w i l l e x p a n d u p t o e ig ig h t t i m e s t h e v o l u m e o f t h e b a s e m e t a l c o n su su m e d a n d f u r t he he r c o r r o d e t h e s t e e l substrate, thu s dislodging any coating ap plied over it. scale is a heav y oxide Mill M ill scal e.— Mill scale l a y e r fo fo r m e d d u r i n g h o t f a b r ic ic a t io io n o r h e a t t r e a t m e n t o f m e t a l s a n d i s a b l u i s h c ol ol o r . M i l l scale will even tual ly break loose from the steel substra te, taking the coating w ith it. it. Steel Steel is is anod ic to to m ill scale (steel has a low low er electricalelectricalchem ical ical p otential difference than m ill scale); scale); there fore, steel wi ll corrod e (sacrifice (sacrifice itself) itself) to p r o t e c t th e m i ll sc a le .
Dirt and dust.— D i r t a n d d u s t o n t h e s u r f a c e p r e v e n t t h e a p p l ic ic a t io io n o f a s m o o t h u n i f o r m f il il m a n d w e a k e n t h e a d h e s io io n o f th th e c o a t in in g t o t h e s u b s t r a t e . lu b l e s a l t s d e p o s i t e d o n a Solu ble sa lts. — S o lu s u r f a c e c a n r e m a i n o n t h e s u r f a ce ce , e v e n a f t e r abrasive cleaning. Soluble Soluble salts will increase increase m o i s t u r e p e r m e a t i o n th th r o u g h t h e c o a ti ti n g (osmotic blistering) blistering) and can accelerate th e c o r r os os i on on r a t e u n d e r t h e c o a t i n g f i lm lm ( u n d e r fi fi l m c or or r o s io io n o r u n d e r c u t t i ng ng ) . T h e m o s t co co m m o n s o l u b l e sa sa l t s e n c o u n t e r e d i n t h e coating ind us try are chlorides, sulfates, sulfates, and m etallic etallic salts. salts. The ch ch loride ion is the m ost aggressive.
Water.— W a t e r w i l l p r e v e n t a d h e s io io n a n d m a y e i t h e r p r o d u c e f la la s h r u s t i n g b e f o r e coating ap plication or it may accelerate u n d e r f i lm lm c o r r o si si o n a f t er er c o a t i n g a p p l i ca ca t i o n . M o i s tu tu r e i n t h e l i q u i d o r f ro ro z e n s t a te te w i ll ll p r e v e n t a d he s i o n o f t h e c oa t i n g t o t h e s u b s t r a t e a n d c a n d i s r u p t c u r i n g r e a c ti ti o n s o f c o a t in in g s . M o i s t u r e c o n t a m i n a t i o n c a n ca ca u s e several typ es of failur failur e. left after the Chalk.— Ch alk is the residu e left d eterioration of the coating’s org anic binder . Chalk results from exp osure of the coating to d irect irect sun light or artificial artificial UV ligh ligh t. All c o a t in in g s c h a l k t o s o m e d e g r e e , b u t e p o x i e s a r e m o r e p r o n e t o ch ch a l k . O v e r c o a t i ng ng c h a l k e d s u r f a c e s w i ll ll r e s u l t i n p o o r a d h e s io io n a n d m a y result in d elamination (separation of one c o a t in in g l a y e r fr o m a n o t h e r co a t i n g l a y e r ) failure. loose, Deteriorated Deteriorated coatings.— Old , loose, d e t e r io io r a t e d c o a t i n g s t h a t a r e o v e r co co a t e d m a y p e el , d e la m in a te , o r lift li ft fr om t h e su b st r at e an d t a k e t he h e n e w c o a ti t in g w i th th t h e m .
(b) Compressed Air Contaminants.— A ir Grease and oil.— G r e a s e a n d o i l p r e v e n t a c o a t in in g f r o m a d h e r i n g t o t h e s u b s t r a t e .
c o m p r e s s o r s co n t a m i n a t e d w i t h m o i s t u r e a n d oil can resu resu lt in in ad hesion-related failures. The
21
Guide to Protective Protective Coatings: Coatings: Inspection and Maintenance f o ll ll o w i n g a r e t w o c o m m o n o p e r a t io io n s t h a t t r a n s f e r o il il a n d w a t e r c o n t a m i n a n t s f r o m t h e comp ressed air supply to the substrate: •
A b ra r a si s i v e su s u r fa f a ce ce p r ep e p a ra r a ti tio n operations
•
Bl ow ow i ng ng d o w n th th e p re r e p ar a r e d s u bs bs t ra ra te te a f t er er s u r f a c e p r e p a r a t i o n t o r e m o v e d u s t b e fo fo r e a p p l y in in g t h e co a t i n g
A i r c om om p r e s so so r s s h ou ou l d b e e q u i p p e d w i t h i n l in in e m o is is t u r e a n d o il il s e p a r a t o r s ( t r a p s ) o n a l l l in in e s . T h e i n sp sp e c t o r s h o u l d h a v e t h e c o n t r a c t o r c h e ck ck t h e a i r s u p p l y f o r c on on t a m i n a n t s i n accordan ce with ATM D 4285. 4285. (See (See a p p e n d i x G f or or t h i s p r o c ed ed u r e . ) I t i s r e c o m m e n d e d t h a t t h e c o m p r e s s e d a i r li li n e s b e c h e c k ed ed o n c e e v e r y 4 h o u r s o r a f t e r t h e c o m p r e s so so r h a s b e e n t u r n e d o ff ff . la s h r u s t in in g ( s om om e t i m e s (c) Flash Rusting.— F la called called flashback ru sting or rust bloom ing) is a light light oxida tion (corrosion) of the ferrou s s u r f a c e a f te te r s u r f a c e p r e p a r a t i o n h a s b e e n c o m p l et et e d . F la la s h r u s t i n g d e v e l o p s o n f re re s h l y p r e p a r e d su r fa ce s i n th e p r e se n ce o f m o ist u r e . A f t e r t h e m o is is t u r e d r i es es o f f, f, a n y r e s u l ti ti n g corrosion is called called flash ru stin stin g and can occu occu r w i t h in in m i n u t e s a ft ft e r su su r f a c e p r e p a r a t i o n . T h e f o ll ll o w i n g t w o c i r cu cu m s t a n c e s a r e th th e m o s t c o m m o n m o i s tu tu r e s o u r c e s re re s u l t i n g i n f la la s h rusting: •
C on on d e n sa sa ti t i o n i s o cccc u r ri rin g
•
W at a t er e r is i s u se s e d in in th t h e s u rf rf a ce ce p r e p a r a t io n m e t h o d
C o n d e n s a t i o n i s th th e f o r m a t i o n o f li li q u i d w a t e r f ro r o m w a t e r v a p o r i n t h e su su r r o u n d i n g a i r a t c e rt rt a i n a m b i e nt nt t e m p e r at at u r e s a n d h u m i d i ty ty r a n g e s . C o n d e n s a t i o n c a n o cc cc u r u s i n g a n y s u r f a ce ce p r e p a r a t i o n m e t h o d b e ca ca u s e it it is is w eather d epend ent. Surface prep aration m e t h o d s t h a t e m p l o y w a t e r a r e w a t e r je je t t in in g a n d w e t a b r a s iv iv e b l a s t c le le a n i n g . F la la s h r u s t i n g c a n b e m i n i m i ze ze d w h e n u s in in g w a t e r je je t t in in g a n d w e t a b r a s i v e b la la s t c le le a n i n g b y t h e f o ll ll o w i n g m e t h o d s :
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Using an inhibitive agent.— Inhibitive a g e n t o r w a s h p r i m e r , n or or m a l ly ly a p h o s p h a t e , i s i n je je c t e d i n t o t h e w a t e r o r b l a s t s t r e a m o r a p p l ie ie d a f t e r c le le a n i n g . R e cl cl a m a t i o n d o e s n o t p ro h ib it th e u se of in h ib it or s, b u t th e s u rf a ce should be thoroughly water w ashed before c o a t in in g b e c a u s e h e a v y i n h i b i t iv iv e r e s i d u e s c a n a d v e r s e l y a f f e ct ct c o a t i n g a d h e s i o n .
Using hot forced forced (blown) air.— Dr y off the w e t t e d s u r f a c e im im m e d i a t e ly ly a f t e r c le le a n i n g w i t h hot air blowers. Using high-pressure, water-jet vacuum cleaning method.— H i g h - w a t e r p r e s s u r e t r a n s f e r s e no no r m o u s e n e r g y t o t h e s u r f a c e , t h u s e l e v a t in in g t h e s u r f a c e t e m p e r a t u r e t o e v a p o r a t e a n y m o i st st u r e , a n d t h e v a c u u m r e m o v e s e v a p o r a t e d a n d l iq iq u i d m o is i s t u re re a w a y . T o p r e v e n t f la la s h r u s t in in g , i t is is a g e n e r a l i n d u s tr tr i a l p r a c t ic ic e n o t t o p r o c ee ee d w i th th s u r fa fa c e p r e p a r a t i o n u n l e s s t he s t e e l su b s t r a t e temp erature is 5 degrees F, minim um , above t h e d e w p o i n t . ( Se Se e ch ch a p t e r VI VI I, I, “ E n v i r o n m e n t a l C o n d i t io io n s ” . ) S u r fa fa c e p r e p a r a t i o n s t a n d a r d s N A C E 1 / S SP SP C SP-5, SP-5, N AC E 2/ SSPC-SP1 SSPC-SP10, 0, N ACE 3/ SSPC-SPSSPC-SP6, N AC E 4/ 4/ SSPC-SP SSPC-SP-7, -7, N AC E 8/ 8/ SSPC-SP SSPC-SP14, 14, SSPC-SP15 SSPC-SP15,, and SSPC-SP11 SSPC-SP11 provid e for recleaning or reblasting to rem ove flash r u s t i n g . T h e su su r f a c e p r e p a r a t i o n s t a n d a r d s SSPC-SP SSPC-SP2, 2, SSPC-SP SSPC-SP3, 3, and N AC E 5/ SSPC-SP SSPC-SP12 12 d o n o t s p e c i fi fi ca ca l ly ly a d d r e s s fl fl a s h r u s t i n g b u t r e q u i r e t h a t t h e s u r f ac ac e b e r e c le le a n e d a cc cc o r d i n g t o c le le a n l i n e s s r e q u i r e m e n t s o f t h e s t a n d a r d u s e d i f r u s t f o r m s o n t h e s u r f a ce ce . R e cl cl a m a t i o n s p e c i fi fi ca ca t i o n s r e q u i r e t h a t a n y s u r f a ce ce w h e r e f la la s h r u s t o r c o r r o s io io n b y p r o d u c t s h a v e f o r m e d b e r e c le le a n e d . If flash flash ru sting is su spected and is not v isibly isibly n o t i ce ce a b l e , a g o o d d e t e c t io io n m e t h o d i s t o inspe ct the surface with a bright flashlight flashlight or s p o t l ig ig h t . T h e l ig ig h t s h o u l d b e h e l d p a r a l l e l t o t h e s u r f a c e a n d s h i n e d a c r o s s it it . R u s t b lo lo o m s w i ll ll a p p e a r a s d a r k e n in g o n t h e s u r f a ce ce a n d h a v e a r e d d i s h o r l ig ig h t b r o w n t i n t .
Surface Preparation
26. Presurface Treatment.— Prior to actual
(a) Nonmetallic Abrasives.— T h e r e a r e t h r e e
surface p rep aration s, all steel surface imp erfections erfections are to be corrected . This is a Reclam Reclam ation specificati specification on requirem ent. Weld spatter , slag, slag, burrs, porosity, sharp ed ges, pits, lamin ations (sliv (sliv ers), crevices, crevices, or objectionable objectionable i rr rr e g u l ar ar i t ie ie s n e e d t o b e r e p a i r e d . S u rf rf a c e d ep ressions, such as pits or crevices, crevices, can be a collection collection point for excessive coating m ater ial that m ay not fully cure. Projections Projections such as w e l d s l a g , s la la g b u r r s , o r s h a r p e d g e s t h a t m a y s t ic ic k o u t t h r o u g h t h e c o a t in in g c an an r e s u l t in in p i n p o in t co r r o sio si o n . A l l t h e se ir r e g u l ar it ie s a r e to be repaired by w elding, scrapping, g r i n d i n g , o r o t h e r s p e c if if ie ie d m e a n s .
b a sic t y p e s o f n o n m e t a llic ll ic a b r a siv si v e s: (1) (1) n atu rally occu occu rring; (2) (2) byp rod ucts; and (3) m anu factured . The following following sections sections p r o v i d e a b r ie f d e sc r ip t i on o f t h e ty p i ca l u s a g e and the degree of dusting produ ced by n o n m e t a l li li c ab ab r a s i v e s d u r i n g b l as as t in in g operations.
Na tural tur al ly occu rrin g.— •
t o u g h , d e n s e , r o u n d - s h a p e d m a t e r i a ls ls . They ar e effective effective for b last cleaning cleaning n e w s t e el e l bu b u t a r e n o t r ec ec o m m e n d e d f o r m a i n t e n a n c e co co a t i n g w o r k . D e g r e e o f d u s t i n g d u r i n g b l a st st i n g o p e r a t i on on s is m edium .
iv e 27. Abrasive Blast Material.— Material.—T h e a b r a s iv b la s t m a te r ia l i s im p or ta n t b ec a u se it d e t e r m i n e s t h e s u r f a c e p r o fi fi le le p r o d u c e d . There are tw o genera l categories of abr asives: m etallic etallic and nonm etallic. etallic. Met allic allic abrasives a r e u s e d p r i m a r i ly ly t o b l a s t cl cl e a n s t e e l a n d f or or g e d o r c a s t ir ir o n w h e r e a s u r f a ce ce p r o f il il e i s s e ld ld o m c r it it i ca ca l o n t h e f in in i sh sh e d p r o d u c t . N o n m e t al lic li c a b r a siv si v e s , d e p e n d in g o n t h e t y p e u s e d , ca ca n p r o d u c e t h e d e s ir ir e d s u r f ac ac e p r o f il il e a n d c le le a n l in in e s s o n h a r d , d e n s e f er er r o u s m e t a l s o r o n s o f t m e t a l s (a (a l u m i n u m , b r a s s , b r o n z e , o r c o p p e r ) w i t h o u t d a m a g i n g o r a l t e r i ng ng t h e metal surface. Reclam Reclam ation specifies specifies SSPC-AB 1, “Ab rasive Specific Specification ation N o. 1, 1, Miner al and Slag Slag Abr asiv asiv es,” es,” C lass lass A , either either Type I or II. II. R e cl cl am am a t io io n s p e c if if ic ic a t io io n s d o n o t p e r m i t abras ive mate rials rials containin containin g toxic heavy m etals such as arsen ic or or solub le salts in in excess of 0.04 0.04 pe rcent. Abrasive m aterial is is not to c o n t a i n m o r e t h a n 1 p e r c en en t s i li li ca ca , b y v o lu lu m e bec b ec a u s e si lica li ca sa n d p a rt i cl e s cau ca u se si li cosi co si s. Reclam Reclam ation doe s not sp ecify ecify meta llic llic abrasives. Metallic abrasives are not field field ap pl icable because of high costs and inability to recycle. recycle. H ow ever, Reclama Reclama tion w ill allow a contract varian ce, if requ ested , to to u se metallic a b r a s i v e s fo fo r s h o p s u r f a ce ce p r e p a r a t i o n , p r o v i d e d t h a t th e m e t al li c a b r a si v e is a d r y , clean, angu lar steel grit.
No ns ilica ilic a or he av y min m in era l san ds (magnetite, olivene r utile, utile, ically stra u roli te). — These sand s are typ ically
•
Flint, garnet, novacu lite lite (siliceous rock ), and zirc o n.— T h e s e a r e d e n s e , t o u g h , a n g u l a r o r c u b i c a b r a s i v e s t ha ha t , be b e c a u s e o f t h e i r h i g h c o s t s , a r e u s e d p r im a r ily il y in sp e cia ci a l cle c le an in g a p p l ic ic at at i o n s . T h e d e g r e e of of d u s t i n g d u r i n g b l as as t i n g o p e r a t i o n s i s m e d i u m f o r fl fl in in t a n d g a r n e t a n d l o w f o r n o v a cu cu l i t e a n d z i r c o n .
Byproduct.— •
Slags Sla gs ( c oa l, cop per , n icke ick e l).— l). — Slag abra sives are generally a glassy, glassy, h o m o g e n e o u s m i x t u r e o f v a r io io u s o x id id e s t h a t a r e s h a r p l y a n g u l a r o r cubic and are efficient efficient for blast c le le a n i n g n e w , r u s t e d , o r p a i n t e d surfaces. These abrasives are not r e cy cy c l ed ed . T h e d e g r e e of of d u s t i n g d uring blasting operations is high for c o a l a n d n i c k e l a n d l o w f o r co co p p e r .
•
Agr icu ltu ral pro duc ts (co rnc obs , pea ch pits , w alnu aln u t shel s hells). ls). — T h e s e a r e generally regarde d as tough but l ig ig h t w e i g h t a b r a s i v e s u s e d i n s p e c ia ia l c le le a n i n g a p p l i ca ca t i o n s f o r r e m o v i n g
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Guide to Protective Protective Coatings: Coatings: Inspection and Maintenance p a i n t , fi f i n e s ca l e , a n d o t h e r c o n t a m i n a n t s w i t h o u t a l t e r in in g t h e m e t a l s u b s t r a t e o r d i s t or or t i n g t h i n m e t a ls ls . T h e d e g r e e o f d u s t in in g d u r i n g b l a st in g o p e r a t io n s i s l o w .
Ma nu factu fact u red .— •
Syn the tic (alumi (al umi nu m o xide, xid e, glass gla ss bea ds, sili co n ca c a rbid e).— e). — These a b r a s i v e s c a n be be p r o d u c e d w i t h spec ific fic prope rties for vary ing d egrees o f h ar ar d n e s s a nd nd t o u g h n e s s a nd nd w i t h specific specific shapes. H igh cost restricts restricts the us e of these abr asives to special c le le a n i n g a p p l i c at at i o n s, s, a n d t h e y m u s t be re cy c le d t o b e e co n om ic a l. Th e m a i n ad ad v a n t a g e s o f u s in in g s y n t h e t i c abrasives are fast cutting cap ability ability a n d n o n r u s t in in g o f t h e s u b s t r a t e . T h e d e g r e e o f d u s t i n g d u r i n g b l as as t in in g o p e r a t i o n s i s lo lo w .
(b) Sampling and and Testing.— Testing.— A b r a s i v e s a m p l e s s h o u l d b e r e t a i ne ne d f o r fu fu t u r e r e f e re re n c e i n t h e e v e n t o f co co a t i n g p r o b l e m s . Sa m p l e s ca ca n b e t e s t e d a n d t h e r e s u l t s r e t a in in e d t o e i t he he r confirm or r eject eject abrasives as a p ossible cause of failure. failure. Different Different abrasives used on the s a m e m e t a l w o r k c a n p r o d u c e d i ff ff e r en en t a p p e a r a n c e s . T e st st i n g s h o u l d b e c o n d u c t e d o n t h e a b r a s iv iv e s b e f o r e u s e t o e n s u r e t h a t t h e m a t e r i a l d o e s n o t c o n t a i n c o n ta ta m i n a n t s .
(c) Sampling.— T h e i n s p e c t o r s h o u l d r e c o r d t h e m a n u f a c tu tu r e r ’ s b r a n d n a m e , b a t c h o r l o t n u m b e r s , a n d a b r a s iv iv e ty ty p e . A b r a s iv iv e m a t e r ia ia l s h o u l d b e s t o r e d i n a d r y e n v i r o n m e n t a n d b e c le le a n , u n i f o rm rm i n t e x tu tu r e , a n d m o i s t u re re f r e e . I t i s r e c o m m e n d e d t h a t a s m a l l s a m p l e o f e a ch ch a b r a s iv iv e b a t c h o r l o t n u m b e r b e k e p t f o r f u t u r e r e f e r e n c e in in c a s e c h a n g e s o c c u r i n t h e s u r f a ce ce p r o f il il e . Soluble salt salt concentra tions are (d) Testing.— Soluble t y p i c a l ly ly l o w f o r m i n e d m i n e r a l a b r a s i v e s (SSPC-AB1 (SSPC-AB1,, type I) and slag slag abrasives (SSPC (SSPC AB1, type II) II) th th at are air cooled cooled or qu enched in p u r ifie if ie d w a t e r . H o w e v e r , s la g a b r a s iv e s m a y b e q u e n c h e d in s e a w a t e r , b r a c k is h w a t e r , o r o t h e r s a lt lt - co co n t a m i n a t e d w a t e r a n d , c o n se se q u e n t l y , h a v e a h i g h e r s o l u b l e s a lt lt
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conten t. Ab rasives w ith high soluble salt content should n ot be used because the salts c a n c on on t a m i n a t e t h e s u b s t r a te te d u r i n g b l a s t in in g o p e r a t i o n s a n d , t h u s , c a u s e c o a t in in g f a i lu lu r e . M i n e r a l a n d s la la g a b r a s i v e s sh sh o u l d b e t e s t e d f o r the p resence of soluble salts salts by a cond uct ivity m e t e r . C o n d u c t iv iv i t y i s t h e i o n i c p r o p e r t y o f a f lu lu i d o r s o l id id t h a t p e r m i t s t h e p a s s a g e o f a n electric electric cur cur rent. Solu Solu ble salts dissolved dissolved in w a t e r c a n b e m e a s u r e d b y a c o nd nd u c t i v it it y m e t e r . C o n d u c t iv iv i t y m e t e r s m e a s u r e t h e cond u ctance of all salts salts (chlorid (chlorid es, sulfates, ferrous, etc.) etc.) in in d issolution but cann ot detect a “spe cifi cific” c” salt ion (e.g., th th e chlorid e ion). R e cl cl a m a t i o n s p e c i fi fi e s t h a t m i n e r a l a n d s la la g a b r a s iv iv e s a r e t o b e i n a c co co r d a n c e w i t h S SP SP C A B 1 , a n d t h e s t a n d a r d ’s c o n d u c t iv iv i t y requ iremen t is is not to exceed 1,000 1,000 m icrosiem icrosiem ens. The ch ch loride-specific loride-specific ion in abrasives can be tested u sin sin g a titra titra tion kit. ( Se Se e ap ap p e n d i x H f o r t e st st p r o c e d u r e s .) .) T es es t in in g f o r t o xi xi c m e t a l s r e q u i r e s l a b o r a t o r y m e t h o d s . Certification Certification or analy sis of abras ive mat erial c o n t e n t i s a v a il il a b le le f r o m t h e m a n u f a c t u r e r . A l t h o u g h w a t e r i s n o t c o ns ns i d e r e d a n a b r a s i v e , i t is is u s e d a s a s u r f a c e p r e p a r a t i o n m e d i u m f o r p r e v io u s l y co a t e d m e t a lw o r k . W a t e r m a y contain an excessive am ou nt of soluble salts salts t h a t , if if l e ft ft a s r e s id id u e o n t h e p r e p a r e d s u r f a c e , can cause the coating coating to blister. blister. The wat er u s e d i n w a t e r je je t t in in g o p e r a t i o n s sh sh o u l d b e tested for high chlorid e ion levels. (See (See a p p e n d i x I f o r p r o c e d u r e s .) .)
28. Nozzle Blast Pressure.— Pressure.—Reclamation d oes not require checking the blast nozzle p r e s su r e . In d u s t r y p r a c tice ti ce r e co m m e n d s th a t t h e b l a s t in in g p r e s s u r e b e m a i n t a i n e d b e t w e e n 9 0 a n d 1 00 00 p o u n d s p e r s q u a r e i n ch ch ( p s i ). ). R e d u c e d p r e s s u r e s ca ca n r e s u l t i n a s h a l lo lo w s u r f a c e p r o fi fi le le d e p t h a n d a d i m i n i sh sh e d b l a s t rate efficiency. efficiency. Excessive Excessive pre ssures can i n c r e a se se t h e s u r f a c e p r o f il il e d e p t h . Consequ ently, the prim e coat may not cover t h e p e a k s o f t h e p r o f i le le a n d p i n h o l e fa fa i lu lu r e m ay resul t. The critical critical po int of pr essure is at t h e b l a s t n o z z l e , w h e r e p r e s s u r e w i ll ll b e l o w e r t h a n a t t h e a i r c om om p r e s s o r b e c a u s e o f h o s e li li n e p re ss u re lo ss e s.
Surface Preparation If the the n ozzle blast pr essure is susp ect, it it is r e c o m m e n d e d t h a t t h e in in s p e c t o r r e q u e s t t h e coating supe rvisor to check the pressur e. (See (See a p p e n d i x J fo fo r t h e p r o c e d u r e . )
29. Surface Preparation Preparation Methods.—Th e follow follow ing are th e five five basic typ es of su rface p r e p a r at io n : • • • • •
D e g r e a si n g . H a nd n d a n d p ow o w e r to to ol o l c l e an a n in in g. g. A br b r as a s iv iv e (w (w e t or o r d ry r y ) cl cl e an a n in in g. g. W a te t e r je je t ti ti n g o r p r es e s su s u r e cl cl e a ni n in g . C he h e m ic ic a l s tr tr ip ip p in i n g. g.
T h e r e a r e s e v e r a l s t a nd nd a r d s d e s c r ib ib i n g t h e a b o v e m e t h o d s ; h o w e v e r , R e cl cl a m a t i o n h a s a d o p t e d S SP SP C an an d jo in in t N A C E / S SP SP C su su r f a c e p r ep a r a ti o n st a n d a r d s. Th e in sp ec t or sh ou ld e n s u r e t h a t t h e a p p l i ca ca b l e st st a n d a r d s a r e available on the jobsit jobsite. e. After su su rface p r e p a r a t i o n , c le a n l ine in e ss sh a l l b e b a s e d on t he s p e c if if ie ie d s t a n d a r d ' s cl cl e a n i n g r e q u i r e m e n t s . V is is u a l s t a n d a r d s b y S S PC PC a n d jo in in t N A C E/ SSPC SS PC ar e a su p p le m en t t o a id in d e t e r m i n i n g c le le a n l i n es es s b u t a r e n o t t h e s o l e c on on f ir ir m a t i o n r e q u i r e m e n t . S u r fa fa c e p r ep a r a ti o n st a n d a r d r eq u ir em en ts sh a ll g o v e r n w h e r e s u r f a ce ce p r e p a r a t i o n a n d v i s u a l stand ard s conflict. conflict. The following following are the SSPC SSPC a n d j o in in t N A C E / S SP SP C s u r f a ce ce p r e p a r a t i o n s t a n d a r d s , i n i n cr cr e a s in in g o r d e r o f c l e a n l in in e s s . A n a b b r e vi v i a t e d s u m m a t i o n i s p r o v id id e d fo r e a c h s u r f a c e p r ep ep a r a t i o n st st a n d a r d a n d t h e c o r r e s p o n d i n g v i s u a l st st a n d a r d t o b e u s e d .
(a) SSPC-SP1: Solvent Cleaning.— Solvent cleaning is used used to rem ove grea se, oil, d irt, d r a w i n g a n d c u t t i ng n g c o m p o u n d s , a n d o t h er er contaminants by solvent wiping, water w a s h i n g , c le le a n i n g c o m p o u n d s , a n d s t e a m cleaning. This proced u re is is a prerequ isite isite for for all other surface preparation m ethods except N A C E 5 / SSP C -SP 12 (w a te r je tt in g ) a n d N A CE 6/ SSP C -SP 13 (con (c on cr et e su rf ac es ). Th e reason for solvent cleanin g is that that c o n t a m i n a n t s le f t o n t h e s u r f a ce ce c a n b e i m p a c te te d i n t o th th e s u b s t r a te te s u r f a ce ce d u r i n g p r e p a r a t i o n u s in g o t h e r m e t h o d s (l ist e d b e lo w ), r e s u l tin g i n p o o r a d h e s io n a n d p r e m a t u r e f a il u r e .
(b) SSPC-SP2: Hand Tool Cleaning.— H a n d tools are used to rem ove loose m ill ill scale, scale, loose ru st, loose coatings, coatings, w eld flux, weld slag, or w eld spatter by brushing, sanding, chipping, or scrapp ing. Tightly adher ing rust, m ill ill scale, scale, a n d p a i n t a r e a ll ll o w e d t o r e m a i n . T h e u s e o f h a n d t o o l s is is g e n e r a l l y c on on f i ne ne d t o s m a l l a r e a s , sma ll repair area s, or sm all ina ina ccessible ccessible areas. T h e v is is u a l s ta ta n d a r d i s d e t e r m i n e d b y comp arison to SSPC-VIS SSPC-VIS 3 referen referen ce p h ot og ra p h s.
(c) SSPC-SP3: Power Tool Cleaning.— P o w e r tools are used to rem ove loose m ill scale, scale, loose ru st, loose coatings, weld flux, weld slag, or w eld spatter. Tightly ad heri ng rust, m ill scale, scale, a n d c o a t in in g a r e a l l o w e d t o r e m a i n i f t h e y c a n n o t b e re re m o v e d b y l i ft ft i n g w i t h a d u l l p u t t y knife. Th e requirements of this method are similar to SSPC-SP2, SSPC-SP2, except that, w ith po w er t o o l s , l a r g e r a r e a s c a n b e c le le a n e d m o r e efficiently. efficiently. The visual stand stand ard is d eterm ined b y co m p ar is o n to SSPC SS PC -V IS 3 r ef e re n ce p h ot og ra p h s. (d) SSPC-SP15: Commercial Grade Power ls a r e u s e d t o Tool Cleaning.— P o w e r t o o ls rem ove all grease, oil, dirt, dirt, du st, mill scale, scale, rust coatings, oxides , corrosion byp rod ucts, and o t h e r f o r e ig ig n m a t t e r t h a t a r e v i s i bl bl e w i t h o u t m a g n i f ic ic a t io io n , e x ce ce p t t h a t r a n d o m s t a in in s a r e a l lo lo w e d o n 3 3 p e r c e n t o f e a c h 9 -i -i n c h s q u a r e area. Stains Stains may consist of light light shad ow s, light s t r e a ks ks , a n d m i ld ld d i s c ol ol o r a t i on on c a u s e d b y r u s t , m i l l s ca ca l e , a n d p r e v i o u s a p p l ie ie d c o a ti ti n g s . S li lig h t r e s i d u e s o f r u st st a n d p a i n t a r e a l l o w e d t o r e m a i n a t t h e b o t t o m o f co co r r o s i on on p i t s , p r o v id e d th a t t h e o r ig in a l su s u b st r a te w a s p it te d . T h i s s t an an d a r d r e q u i re re s a m i n i m u m s u r f a c e p r o f ile o f n o t l e ss t h a n 1 m il b e r e t a in e d o r p r o d u ce d . C u r r e n t ly , t h e r e is n o v i su a l r e f e r e n ce ce p h o t o g r a p h s fo fo r t h i s st st a n d a r d .
(e) NACE 4/SSPC-SP7: Brushoff Blast cleaning em ploy s Cleaning.— Brush-off blast cleaning abrasive blasting to rem ove all grease, oil, oil, d irt, d ust, loose mill scale, scale, loose loose ru st, an an d loose coatings that are visible visible withou t m agn ific ification. ation. Tigh Tigh tly ad ad herin g rust, mill scale, scale, and coating s a r e a l lo lo w e d t o r e m a i n i f t h e y c a n n o t b e
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Guide to Protective Protective Coatings: Coatings: Inspection and Maintenance r e m o v e d b y l if if t in in g w i t h a d u l l p u t t y k n i fe fe . The visu al stand ard is SSPC-V SSPC-VIS IS 1 referen referen ce p h ot og ra p h s.
(f) NACE 8/SSPC-SP14: Industrial Blast Cleaning.— I n d u s t r i a l b l a s t cl cl e a n i n g e m p l o y s abrasive blasting to rem ove all visible grease, o i l, l, d i r t , a n d d u s t t h a t a r e v i s ib ib l e w i t h o u t m agn ificatio ification n . Traces Traces of of tightly ad hering m ill s c a le le , r u s t , a n d c o a t in in g r e s i d u e a r e a l l o w e d t o r e m a i n o n 1 0 p e r c e n t o f e a ch ch 9 i n c h s q u a r e a r e a , p r o v i d e d t h a t t h e d i st st r i b u t i o n i s e v e n . Traces of rust, mill scale, scale, and coatings are a l lo lo w e d t o r e m a i n i f t h e y c a n n o t b e r e m o v e d by b y l ift if t in g w i t h a d u l l p u t ty k n i fe. fe . Sh a d ow s, s t r ea ea k s , a n d d i s co co l o r a t io io n c au au s e d b y r u s t , m i ll ll s ca ca l e , a n d p r e v i o u s l y a p p l ie ie d c o a t in in g s a r e a c ce ce p t a b l e . T h e vi vi s u a l st st a n d a r d i s d e t e r m i n e d b y co m p ar is o n to SS PC -V IS 1 r e fe r en ce p h ot og ra p h s. Pickling rem oves all (g) SSPC-SP8: Pickling.— Pickling m i ll ll s ca ca l e a n d r u s t t h a t a r e v i s i b l e w i t h o u t m agn ification, ification, by chem ical reaction (acid (acid bath ) or electrolysis (anod (anod ic electrical electrical current) or bo b o t h . A c c e p t a n c e cri cr i t e r ia a r e t o b e e s t a b l is h e d be t w ee n co nt r a c t in g p a r ti e s.
(h) NACE 3/SSPC-SP6: Com mercial Blast Cleaning.— C o m m e r c ia ia l b l a s t c le le a n i n g e m p l o y s abrasive blasting to rem ove all grease, oil, oil, d irt, d ust , mill scale, scale, rust, coatings, oxide, corro sion sion b y p r o d u c t s, a n d o t h e r fo r e ig n m a t te r th a t a r e visible w ithou t ma gnification, gnification, except for r a n d o m s t a i n i n g . St a i n i n g m a y c o n s is is t o f l ig ig h t s h a d o w s , s li li g h t s t r e a k s , o r m i n o r s t r e a k s caused by ru st, mill scale, scale, or p reviou sly ap plied coatings. At least least tw o-thirds of each 9-inch-squar 9-inch-squar e area shall be free of all visible r e s id id u e , a n d o n l y t h e a b o v e - m e n t i o n e d s t a in in i n g m a y b e p r e s e n t i n t h e r e m a i n d e r o f t h e a r e a . T h e v is is u a l s ta ta n d a r d i s d e t e r m i n e d b y comp arison to SSPC-VIS SSPC-VIS 1 referen referen ce p h o to g r ap h s .
(i) NACE 2/SSPC-SP10: Near-white metal blast cleaning.— N ea r -w h it e m et a l b la s t cl e a n in g e m p l o y s a b r a s iv iv e b l a s t in in g t o r e m o v e a l l g r e a s e , oil, d irt, du st, mill scale, scale, rust, coatings, oxide, c o r r o s io io n b y p r o d u c t s, s, a n d o t h e r f o r e i gn gn m a t t e r that are visible w ithou t magn ification, ification, except f o r r a n d o m s t a i n i n g . St a i n i n g m a y c o n s is is t o f
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l ig ig h t s h a d o w s , s li li g h t s t r e a k s , o r m i n o r s t r e a k s caused by ru st, m ill scale, scale, or p reviou sly sly ap plied coatings. At least 95 95 per cent of each 9inch-squa re area shall be free of all all visible r e s id id u e , a n d t h e r e m a i n d e r o f t h e a r e a s h a l l h a v e o n l y th th e a b o v e - m e n t i o n e d s t a i n i n g . T h e v i s u a l st st a n d a r d i s d e t e r m i n e d b y c o m p a r i s on on to SSPC-VIS SSPC-VIS 1 reference ph otograp hs.
(j) NACE 1/SSPC-SP5: White Metal Blast la s t c le le a n i n g e m p l o y s Cleaning.— W h i t e m e t a l b la abrasive blasting to rem ove all grease, oil, oil, d irt, d ust , mill scale, scale, rust, coatings, oxide, corro sion sion b y p r o d u c t s, a n d o t h e r fo r e ig n m a t te r th a t a r e visible w ithou t m agn ifica ification. tion. The resu lting lting b la s te d s u r fa ce is g en e r a lly ll y a u n ifo if o r m g r a y w hite color. color. Variation in color caused by steel typ e, original original surf ace condition, steel thickness, weld m etal, m ill or fabrication m a r k s , h e a t t r e a t m e n t , h e a t -a -a f f ec ect e d z o n e s , bl a st i ng a br a si ve s, or d i ff er en c e s in b l as t p a tt er n is a cc ep ta b le . Th e v isu is u a l s t a n d a r d is d e t e r m i n e d b y c o m p a r i s o n t o S S P C -V -V IS IS 1 r e f er er e n c e p h o t o g r a p h s .
(k) NACE 5/SSPC-SP12: Surface Preparation Preparation an d C lea nin g o f Stee St ee l a nd Othe Ot he r H ard Me ta ls by Hi gh- and Ul tra -Pr ess ure Wa te r J etting ett ing Pri or to Recoating.— H i g h - o r u l t r a - h i g h w a t e r j et et b la s ti n g em p lo y s w a te r b la s ti n g to r em ov e a ll grease, oil, dirt, du st, mill scale, scale, rust coatings, o x id id e s , c o r r o s io io n b y p r o d u c t s , a nd nd o t h e r f o r e ig ig n m a t t e r t h a t a r e v i s i bl bl e w i t h o u t m agn ificatio ification n . Rem Rem ove n onv isible isible solub le s a lt lt s t o a ll ll o w a b l e l i m i t s t h a t r e q u i r e p h y s i ca ca l t e s t in in g t o v e r i fy fy . T h e s ta ta n d a r d d e f in in e s t h e fo l l o w i n g f o u r d if fe fe r e n t w a t e r p r e s s u r e s : (1) (1) low low -pressu re w ater cleaning at less that 5,000 5,000 ps i; (2) (2) high-pr essure w ater cleaning at 5,000 5,000 to 10,00 10,000 0 psi; (3) high -pre ssu re w ater jet ti n g at 10 ,000 ,0 00 to 25,0 25 ,000 00 p si ; a n d (4 ) u lt r a h ig h p r e s su r e w a t e r jet tin ti n g a t g r e a t e r th a n 25,00 25,000 0 psi. The d egree of cleanliness cleanliness is divided into two categ categ ories: visible contam inant s and nonv isible isible contam inan ts. Visible Visible contam inan ts are subd ivided into four classifi classifications, cations, d esignated WJ-1 throu gh WJ-4 (WJ-1 (WJ-1 is the cleanest) on the basis of allow allow able visible rust, coatings, mill scale, scale, and foreign m atter v e r i fi fi ed ed w i th th o u t m a g n i fi fi ca ca t i on on . N o n v i si si b l e c o n t a m i n a n t s a r e s u b d i v id id e d i n t o t h r e e classification classification s, d esign ated SC-1, SC-1, SC-2, and SC-3
Surface Preparation (SC-1 (SC-1 is is th e clean clean est) on th e basis of allow allow able soluble chloride ions, iron-soluble salts, or sulfate ions. The visible visible an d non visible visible allowab le cont cont amin ant levels are specifi specified ed by the d esignation W J-x/ SC-x; “x” indicates the s p e c i fi fi e d d e f i n i ti ti o n n u m b e r . T h e v is is u a l s t a n d a r d w i ll ll b e d e t e r m i n e d b y c om om p a r i s o n t o S SP SP C - V IS IS 4/ 4/ N A C E 7 r e fe fe r e n c e p h o t o g r a p h s . Reclam Reclam ation sp ecifi ecifies es W J-2/ SC-2 for for all i m m e r s io io n s e r v i c e e x p o s u r e s . W a t e r j et et t i n g c a n n o t p r o d u c e a s u r f a ce ce p r o fi fi le le w i t ho ho u t t h e a d d i t io io n o f a b r a s iv iv e s i n t o t h e je je t flow flow and , therefore, is is not spec ified ified for surfaces w ithou t a sur face profile, e.g., new constru ction ction steel. Reclam Reclam ation specifies specifies this s t a n d a r d o n l y f o r p r e v i o u s l y c o at at e d s u r f a ce ce s t h a t h a v e a n e x is is t in in g s u r f a c e p r o f il il e .
T h i s is is a n e x ce ce ll ll e n t m e t h o d f or or r e m o v i n g o l d p a i n t a n d c o n t a m i n a n t s u s in g o n l y p r e s s u r i z e d w a t e r . W a t e r je je t t in in g e q u i p m e n t ca ca n b e v a c u u m s h r o u d e d t o p r e v e n t sp sp r a y a n d h a v e in-line in-line filters filters to separ separ ate ou t old p aint and c o n t a m i n a n t s . S o m e m a n u f a c t u r e r s ar ar e experim enting w ith injecting injecting abrasives into the w a t e r - je je t st st r e a m t h a t w o u l d b e ca ca p a b l e o f p r o d u c in g a s u r f a ce p r o f il e .
(a) SSPC-VIS 1: Visual Standard for for Abrasive Abrasive ie s Blast Blast C leaned Steel.— T h i s g u i d e s h o w s a s e r ie of photographs of unp ainted carbon steel be b e fo r e a n d a ft e r a b r a s iv e b l a s t c lea le a n i n g . Bel o w is an abbreviated explanation of the p r oc ed u r es to fo ll o w b ef o r e a n d af t er cl ea n in g t h e s t e e l. l. T h e p r o c e d u r e s a r e f o ll ll o w e d b y a n example. 1.
B ef ef or or e a b ra r a s iv iv e b l as as t cl cl ea ea n i n g , m at at c h t h e e x i s t in in g s u r f a c e c on on d i t io io n w i t h t h e “ i n i t ia ia l c on on d i t io io n ” s h o w n i n o n e o f t h e p h o t o g r a p h i c s ta n d a r d s . In i ti a l c o n d i t i o n s (o (o r r u s t g r a d e s ) a r e p h o t og r a p h s A , B, C , a n d D a n d a r e d e f i n e d i n s e ct ct i o n 4 .1 .1 o f th th e s t a n d a r d . Various ar eas of the surf ace to be c le le a n e d m a y m a t c h o n e o r m o r e i n i t ia ia l condition photographs.
2.
F r om o m t h e s p ec ec if if i ca ca t io io n s, s , d e t er er m i n e t h e s p e c i f ie ie d s u r f a c e p r e p a r a t i o n s t a n d a r d . T h e s u r f a ce ce p r e p a r a t i o n s t a n d a r d w il l b e o n e o f t h e f o ll ll o w i n g : N A C E 1/ SSP C -SP 5, N A C E 2/ SSP C SP10, SP10, N AC E 3/ 3/ SSPC-SP6, SSPC-SP6, or N AC E 4/ SSPC-SP SSPC-SP7. 7.
3.
F ro r o m t a b le le 1 i n t h e v is is u a l s ta ta n d a r d , select the specified specified surf ace prep aration s t a n d a r d a n d t h e i n it it i a l c o n d i t i on on t o o b t a i n t h e co co r r e c t p h o t o g r a p h i c designation.
4.
E v a lu lu a t e t h e fi fi n is is h e d b la l a s t su su r f a ce ce a g a i n s t t h e s e l ec e ct e d p h o t o g r a p h i n s t e p 3 a b o v e t o d e t e r m i n e i f th th e s u r fa fa c e m eets th e specified specified surface p r e p a r a t io n r e q u ir e m e n t s fo r cleanliness.
T h i s i s a n e x c el el le le n t m e t h o d f or or r e m o v i n g o l d p a i n t a n d c o n t a m i n a n t s u s in g o n l y p r e s s u r i z e d w a t e r . W a t e r je je t t in in g e q u i p m e n t ca ca n b e v a c u u m s h r o u d e d t o p r e v e n t sp sp r a y a n d h a v e in-line in-line filters filters to separate out old pa int and c o n t a m i n a n t s . S o m e m a n u f a c t u r e r s ar ar e experim enting w ith injecting injecting abrasives into the w a t e r -j -je t s t r ea ea m t h a t w o u l d b e ca ca p a b l e o f p r o d u c ing in g a s u r f a ce p r o f il e .
30. Photographic Inspection Standards.— T h e i n s p e c t o r s h o u l d i n s p e c t t h e s u r f a c e b e fo fo r e a n d a f t e r s ur ur f a c e p r e p a r a t i o n t o e v a l u a t e c le le a n l in in e s s . S SP SP C a n d N A C E / S SP SP C s t a nd nd a r d v i s u a l r e f e r e nc nc e p h o t o g r a p h s a r e a s u p p l e m e n t a l a i d t o e v a l u a t i n g c l e a n l in in e s s b u t a r e n o t i n t e n d e d a s a s u b s t it it u t e f or or s u r f a c e c le le a n l in in e s s r e q u i r e m e n t s d e f i ne ne d i n t h e surface prep aration stand ard used. The reason for inspecting the su rface before su rface p r e p a r a t io n i s th a t d iffe if fe r e n t d e g r a d a t io n s o n the sam e steel surface (e.g., (e.g., heavy m ill scale scale w i t h l ig ig h t a n d h e a v i l y r u s t e d a r e a s ) w i l l h a v e a d i f fe fe r e n t a p p e a r a n c e a f t e r u s in in g t h e s a m e surface prep aration m ethod . Thus, steel s u r f a c e s th th a t a r e a c ce ce p t a b l y cl e a n w i ll ll a p p e a r d i f f er er e n t , d e p e n d i n g o n t h e i n i t ia ia l s t e e l condition an d the surface preparation m ethod e m p l oy oy e d . Be lo lo w a r e t h e v i su su a l r e fe fe r e n c e s t a n d a r d s f o r a b r a s iv iv e b l a s t c le le a n i n g , h a n d a n d p o w e r t o ol cl e a n i n g , w a t e r jet cle a n i n g , a n d w et abr abr asive blast cleaning cleaning .
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Guide to Protective Protective Coatings: Coatings: Inspection and Maintenance Ex a m p l e : A s t e e l t r a s h r a c k h a s b e e n d e l i v e r e d t o t h e jo b s i te te u n c o a t e d a n d s t or or e d o u t s id id e w i t h o u t p r o t e c t i on on . T h e t r a s h r a c k i s sh sh o w i n g e v i d e n c e o f u n i fo fo r m c o r r o si si o n a n d n o p i t ti ti n g b e f o r e co co a t i n g . T h e s p e c i fi fi e d s u r f a c e p r e p a r a t i o n m e t h o d is N ACE 2/ SSPC-SP SSPC-SP10 10..
s t a n d a r d w il l b e o n e o f t h e fo fo l lo lo w in g : SSPC-SP2, SSPC SSPC -SP3, or SSPC-SP11. 3.
Step Step 1: The existing existing su rface a p p e a r a n c e m o s t c l os os e l y r e p r e s e n t s r u s t g r a d e “ B .” .”
Reclam Reclam ation allow s the contractor to c h o s e th th e t y p e o f h a n d o r p o w e r t o o l t o ac ac c om om p l i sh sh t h e w o r k . D e t e r m i n e t h e t y p e o f t o o l to to b e u s e d f r o m t h e contractor. The following following de signation codes are u sed in the stand ard to i d e n t i fy fy v a r io io u s h a n d a n d p o w e r t o o l s : SP 2 : H a n d w i r e b r u s h .
Step Step 2: Table 1 sh sh ow s th th at for su su rface p r e p a r a t i on N A C E 2 / SSP C - SP10 SP 10 a n d r u s t g r a d e “ B ,” ,” t h e f in in i s h e d b l a st st s u r f a c e sh sh o u l d c o rr rr e s p o n d t o p h ot og r a p h B SP10 SP 10 .
SP 3 / P W D : P o w e r w i r e b r u s h . ( R ec ec la la m a t i o n d o e s n o t p e r m i t r o t a r y p o w e r w ir e b r u s h i n g b e c a u s e t h e t o o l h a s t h e t e n d e n c y t o bu bu r n i s h o r p o l is is h t h e m e t a l s u r f a ce ce , t h u s r e m o v i n g a n y existing existing surface p rofile.) rofile.)
Step 3: Evaluate the finished finished blast s u r f a ce ce a g a i n s t p h o t o g r a p h B SP SP 1 0 t o d e t e r m i n e i f t he he s u r f a c e m e e t s N A CE 2/ SSP C - SP1 0 cl ea n li n es s requirements.
S P3 P3 / S D: D: P o w e r s a n d i n g d i s c . S P 3/ 3 / N G : P o w e r n e e d le le g u n . SP11: SP11: Pow er rotary flap flap peen or n e e d l e g u n ( to to p r o d u c e a su su r fa fa c e p r ofil of il e ). S P1 P1 1/ 1/ R : P o w e r t o o l u s i n g n o n w o v e n d isks (to (to restore existing surface p r ofil of il e ).
(b) SSPC-VIS 3: Visual Standard for Power and Ha nd- To ol Cl ean ed S teel .— T h i s g u i d e s h o w s a s e r ie ie s o f p h o t o g r a p h s o f u n p a i n t e d a n d p a i n t e d c a r b o n s t e e l b e fo fo r e a n d a f te te r h a n d - a n d p o w e r - t o o l c le le a n i n g . Be l o w i s a n abbreviated explanation of the procedures to follow follow before an d after cleaning cleaning th e steel. steel. The p r o c e d u r e s a r e f o ll o w e d b y a n e x a m p l e . 1.
2.
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4.
F ro r o m t a b le le 1 i n t h e v is is u a l s ta ta n d a r d , select the specified specified surf ace prep aration s t a n d a r d a n d t h e i n it it i a l c o n d i t i on on t o o b t a i n t h e co co r r e c t p h o t o g r a p h i c designation.
5.
E va v a lu l u aatt e th t h e fi f i ni n i s he he d h a n d o r p o w e r tool surface against the sel ected p h o t o g r a p h i n s t e p 4 a b o v e t o d e t e r m i n e i f t h e s u r f a ce ce m e e t s t h e s p e c i fi fi e d s u r f a c e p r e p a r a t i o n requirements for cleanliness.
Before Before hand - or pow er-tool clean clean ing, m atch the existing existing su rface cond cond ition ition t h a t m o s t c lo lo s e l y r e p r e s e n t s t h e a p p e a r a n c e w i t h t h e “ i n i t ia ia l c o n d i t io io n ” s h o w n i n on on e o f t h e p h o t o g r a p h i c s t a n d a r d s . I n i ti ti al al c o n d i t io io n s ( o r r u s t grad es) A, B, B, C, and D are for un coated surfa ces; cond itions E, F, and G a r e f o r p r e v i o u s l y p a i n t e d s u r f a ce ce s . Initial Initial cond itions itions are d efined in section 4 .1 .1 o f t h e s t a n d a r d . V a r i ou ou s a r e a s o f t h e s u r f a c e t o b e c le le a n e d m a y m a t c h o n e o r m o r e i n i t ia ia l c o n d i t i o n p h ot og ra p h s.
is t in in g c o a t e d r a d i a l g at at e Ex a m p l e : A n e x is r e q u i r e s s p o t r e p a i r s . T h e co co a t i n g h a s d e t e r i o r a t e d o r p e e l ed ed o ff ff in in s m a l l
From the sp ecifications, ecifications, d eterm ine the s p e c if if ie ie d s u r f a ce ce p r e p a r a t i o n s t a n d a r d . T h e s u r f a ce ce p r e p a r a t i o n
l o ca ca l iz iz e d a r e a s , a n d r u s t i s e v i d e n t b u t there is no visible pitting. The specified specified sur face face pr epa ration m ethod is SSPC-SP SSPC-SP11 11,, a n d t h e c o n t r a ct ct o r u s e d a n e e d l e g u n .
Surface Preparation specified specified d egree of cleaning is WJ-2 WJ-2..
Step Step 1: The existing existing su rface a p p e a r a n c e m o s t c l os os e l y r e p r e s e n t s rust grad e “C.”
N o t e: The d esignation SC-3 in the a b o v e e x a m p l e d e n o t e s ac ac c ep ep t a b l e d egree of cleaning for allow allow able n o n v i s ib ib l e s o l u b l e s a l t c o n t a m i n a n t s after w ater jet jet cleaning. cleaning. The gu ide d o e s n o t a t t e m p t t o s h o w n o n v i si si b l e contaminants by photographic illustra illustra tion. Physical testing is r e q u i r e d t o d e t e r m i n e c o m p l i a n c e fo fo r n o n v i su su a l c on on t a m i n a n t s a n d i s
Step 2: Select pow er tool d esignation SP11 because a needle gun p ow er tool w as used to prepare the surface. Step 3: From tab le 1, 1, the finished finished s u r f a c e p h o t o g r a p h t h a t c o r r es es p o n d s t o ru ru s t g r a d e “ C ” a n d s u r fa fa c e p r e p a r a t io n S SP C - SP 1 1, a n d t h e t o o l used is C SP11 SP11.. Step Step 4: Evaluate the finished finished surface against photograp h C SP11 to d e t e r m i n e i f t h e s u r f a ce ce m e e t s S SP SP C SP11 clean clean liness liness requ iremen ts.
discus sed in sub section section 28, 28, “Testing “Testing f o r C h l o r i d e s o n P r e p a r e d S u r f a ce ce s .” .” 3.
T h e g u id id e s ho h o w s p h ot o t o gr gr a ph ph s o f t h e follow follow ing four d egrees for flash flash ru sting: (1) (1) no rusting, (2) (2) light, light, ( 3) 3) m e d i u m , a n d ( 4) 4) h e av av y . T h e se se d e g r e e s o f f la la s h r u s t in in g a r e t h e d e g r e e s o f ru ru s t in in g a l lo lo w e d t o r e m a i n on the su rface after after w ater jet jet cleaning . T h e d e g r e e s o f fl fl a s h r u s t i n g a r e d e n o t e d i n t h e g u i d e b y t h e f o ll ll o w i n g : (1) (1) no letter designat ion for no rust ing, (2) (2) L for for light, (3) (3) M for m ed ium , and (4) (4) H for heavy . For examp le, if light light f la la s h r u s t in in g i s a l lo lo w e d b y t h e specificatio specification n s, a p ossible surface p r e p a r a t io n w o u l d b e N A C E 5/ SSP C SP12 WJ-2/ WJ-2/ SC-3 L, whe re L is the a l lo lo w a b l e a m o u n t o f fl fl a s h r u s t i n g , a n d i t is is d e n o t e d i n t h e g u i d e p h o t o g r a p h s as W J-2 L.
4.
F ro r o m t a b le le 1 i n t h e v is is u a l s ta ta n d a r d , select the d egree of cleaning, cleaning, den oted by b y W J-1, - 2, - 3, o r -4 , c o r r e sp o n d i ng t o the initial cond cond ition ition to obtain the c o r r e ct ct p h o t o g r a p h i c d e s ig ig n a t i o n .
5.
I f t h e s p ec e c if if ic ic a ti ti o n s a l lo lo w f l as as h r u s t i n g to rem ain on th e surface, use table 2 in in t h e v i s u a l st st a n d a r d t o o b t a in in t h e c o rr rr e c t p h o t o g r a p h i c d e s i g n a t i o n . T h e g u i d e s h o w s p h o t o g r a p h s f o r th th e f o u r d e g r e e s o f r u s t i ng ng p a i r e d o n l y w i t h t h e i n i ti ti a l co co n d i t io io n s C a n d D .
6.
E va v a l ua ua t e th t h e fi f i n is is he h e d w a t er e r je je t te te d surface against the selected
(c) NACE 7/SSPC-VIS 4: Guide and and visual visual re ferenc fer enc e ph otogr oto gr aph s for ste el c lea ne d by es o f water jetting.— T h i s g u i d e s h o w s a s e r i es p h o t o g r a p h s o f u n p a i n t e d a n d p a i n t e d c a r b o n steel before before an d a fter water jet cleaning . Be l o w i s a n a b b r e v i a t e d e x p l a n a t i on on o f t h e p r oc ed u r es to foll fo ll o w b ef o r e a n d aft af t er cl ea n in g t h e s t e e l. l. T h e p r o c e d u r e s a r e f o ll ll o w e d b y a n example. 1.
2.
Be f or or e w a t er e r je je t cl c le a n i n g, g, m a t ch ch t h e existing existing su rface cond cond ition ition that m ost c lo lo s e l y re re p r e s e n t s t h e a p p e a r a n c e w i t h t h e “ i n i t ia ia l c o n d i t io io n ” s h o w n i n o n e o f t h e p h o t o g r a p h i c s t a n d a r d s . I n i ti ti a l c o n d i t i o n s (o (o r r u s t g r a d e s ) B a n d C ( in in i t ia ia l co co n d i t io io n p h o t o g r a p h s A a n d B a r e n o t i n c lu lu d e d i n t h e g u i d e ) a r e fo fo r un coated surfaces. Con ditions E, F, G, a n d H a r e f o r p r e v i o u s ly ly p a i n t e d surfaces. Initial Initial cond cond itions are defined in section section 4.1 of the stand ard . Various a r e a s o f t h e s u r f a ce ce t o b e c l e a n e d m a y m a t c h o n e o r m o r e i n i t ia ia l c o n d i t i on on p h o to g r ap h s . F r om om t h e s p e c if if ic ic a t io io n s , d e t e r m i n e t h e specified specified d egree of cleaning d e s ig ig n a t e d b y o n e t h e fo fo l l o w in in g : W J 1, WJ-2, WJ-3, or W J-4. J-4. A p ossib le surface prepara tion method could be N A C E 5/ SSP C -SP 12 W J-2/ SC -3; -3 ; t h e
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Guide to Protective Protective Coatings: Coatings: Inspection and Maintenance p h o t o g r a p h i n st e p 4 a nd 5 a b o v e t o d e t e r m i n e i f th th e s u r f a ce ce m e e t s t h e s p e c i fi fie d s u r f a c e p re re p a r a t i on on r e q u i r e m e n t s for cleanliness. Ex a m p l e : The coating on the inte rior surfa ce of an existing steel pipe has d e t e r io io r a t e d , a n d e x t e n s iv iv e r u s t in in g a n d p it ti n g is ev id en t. Th e s p ec if ie d su rf a ce p r e p a r a t io n m e th o d is N A C E 5/ SSP C SP12, WJ-2/ WJ-2/ SC-2 L. L.
Step Step 1: The existing existing su rface a p p e a r a n c e m o s t c l os os e l y r e p r e s e n t s rust grade “D.” Step 2: From tab le 1, 1, the finished s u r f a c e p h o t o g r a p h t h a t co co r r e s p o n d s t o r u s t gr gr a d e “ D ” a n d d e g r e e o f cleanin g W J-2 is is D W J-2.
m a t e r ia ia l r e q u i r e s a d e e p e r p r o f il il e , t r a d i t i o n a l a b r a s iv iv e b l a st st c le le a n i n g m u s t b e e m p l o y e d . The followin followin g sections sections p rovid e altern ative c le le a n i n g m e t h o d s w i t h a n a b b r e v i a t e d description.
(a) Sponge Abrasive Blasting.— Blasting.— T h i s m e t h o d f o ll ll o w s t h e t r a d i t io io n a l a b r a s i v e b l a s t m e t h o d s , e x ce ce p t t h a t t h e a b r a s i v e p a r t i c le le s a r e e n c a p s u l a t e d i n a s p o n g e m a t e r i a l. l. T h e s p o n g e m a t e r i a l p r e v e n t s a b r a s i v e p a r t i c le le s f r o m b r e a k i n g u p a n d d i ff ff u s i ng ng o n i m p a c t , t h u s r e d u c in i n g t h e a m o u n t o f d u s t . Sp o n g e bl b l a st in g c r e a t e s a b o u t 10 t o 20 p e r c en t o f t h e d u s t t h a t w o u l d b e c r e a te te d b y n o n e n c a p s u l a t e d a b r a s i ve ve m a t e r i a ls ls . T h e m e t h o d d o e s c r e a t e a s u r f a c e p r o f il il e , a n d t h e surface clean clean liness liness can be comp ared to SSPCSSPCVIS 1.
(b) Soda Bicarbonate Blasting.— Blasting.— T h i s m e t h o d Step Step 3: From From table 2, 2, th th e allow allow able l ig ig h t f l a sh sh r u s t in in g t o r e m a i n o n t h e f in in i sh sh e d s u r f a ce ce i s p h o t o g r a p h D W J -2 -2 L , c o r r e sp sp o n d i n g t o r u s t g r a d e “ D ” and ligh ligh t flash flash ru sting “L.” “L.” Step 4: Evaluate the finished finished w ater jet je t te d s u r f a ce a g a in s t p h o t o g r a p h D WJ-2 to determ ine if the su rface meets N A C E 2 / S SPC -SP 10 cl e a nl i ne ss r e q u i r e m e n t s a n d a g a in in s t p h o t o g r a p h D W J-2 L for for allow allow able rem aining surface flash ru st. light N o t e: In the abo ve examp le, if light f la la s h r u s t in in g i s n o t a l l o w e d b y t h e sp ecification ecification s (i.e., (i.e., the su rface p r e p a r a t io n m e th o d is N A C E 5/ SSP C SP12 SP12 W J-2/ SC-2), SC-2), selecti selection on and e v a l u a t i o n o f p h o t o g r a p h D W J- 2 L i n
p r o p e l s larg la rg e c ry s t a l s o f s o d a b i c a r b o n a t e ( b a k in in g s o d a ) b y p r e s su su r i ze ze d a ir ir o r w a t e r . I t i s u s e d m o s t ly ly a s a s tr tr i p p e r fo r c l e an an i n g c o n t a m i n a n t s a n d f or or t h i n c o a t in in g s . T h e r e is is n o s u r f ac ac e c l ea ea n l i n e s s s ta ta n d a r d f or or t h i s m ethod ; how ever, cleanliness cleanliness can be sp ecified ecified t o m e e t t h e r e q u i r e m e n t s o f a co co n s en en s u s surface pr epa ration (e.g., (e.g., NA CE 3/ 3/ SSPC-SP SSPC-SP6) 6).. ls i ce ce (c) Ice Blasting.— T h i s m e t h o d p r o p e ls p ar ti cl es b y p re ss u ri z ed ai r . O n im p ac t , t h e ic e exerts a sheer force across the substrate s u r f a ce ce , r e m o v i n g c o n t a m i n a n t s a n d t h i n coatings. If dry ice is used , it shou shou ld not be u s e d i n c o n f in in e d s p a c e s b e c a u s e o f c a r b o n d i o x id id e b u i l d u p . T h e r e i s n o s u r f a c e c le le a n l i n e s s st st a n d a r d f o r t hi hi s m e t h o d ; ho ho w e v e r , cleanliness can can be sp ecified ecified to mee t the r e q u i r e m e n t s o f a co co n s e n s u s su su r fa fa c e p r ep a r a ti o n (e.g (e .g ., N A C E 3 / SSPC SS PC -SP6 -S P6). ).
s t e p s 3 a nd nd 4 a r e e xc xc lu lu d e d . ca l s tr tr i p p e r s (d) Chemical Strippers.— C h e m i ca
31. Alternative Alternative Surface Preparation Methods.— There are alternatives to t r a d i t i o n a l a b r a s iv iv e b l a s t c le le a n i n g m e t h o d s t h a t m a y r e d u c e s u r f ac ac e p r e p a r a t i o n c o st st s , d u s t , o r f o u l in in g o f m a c h i n e r y b y s m a l l a b r a s iv iv e p ar t ic l e s. Th e se a l te r n a t i ve m e th o d s, u n l e ss o t h e r w i se se n o t e d , a ss ss u m e a n e xi xi s ti ti n g s u r f a c e ( a n c h o r ) p r o f il il e o n t h e s u b s t r a t e s u r f a c e d o e s exist. If a sur face profile d oes not exist, or new
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can be classifi classified ed into tw o generic comp osition osition typ es: (1) bond breake rs and (2) caustic. Bond b r ea k er st r ip p er s w or k b y b r ea k in g th e p a in t' s m o l e c u l a r b o n d s b e t w e e n p a i n t la la y e r s a n d b e t w e e n t h e p a i n t a n d t h e s u b s t r a te s o t h a t p a in t w ill cr in k le u p a n d b e ea sil y r e m o v e d . Bo n d b r e a k e r s t r i p p e r s c a n c o n t a i n t o l u e n e , m e t h y l e n e ch ch l o r i d e , o r m e t h y l e t h y l k e t o n e t h a t r e m o v e s p a i n t s i n a r e l a t iv iv e l y s h o r t t i m e
Surface Preparation b u t m a y b e co n sid e r e d h a z a r d o u s t o w o r k e r s. L e ss ss h a z a r d o u s b o n d b r e a k e r s c o n t a i n N m e t h y l - p r y r r o l id id o n e ( N M P ) o r d i b a s ic ic e s t e r ( D B E) E) co co m p o u n d s , b u t t h e s e r e m o v e p a i n t le le s s q u i c k l y . Bo n d b r e a k e r s tr tr i p p e r s w i ll ll r e m o v e all coating coating s except oil-based oil-based , inor inor gan ic, ic, and m etallic etallic coatings. Caus tic stripp ers w ork by s o ft ft e n i n g t h e e n t i r e p a i n t s y s t e m r a t h e r t h a n b r e a k in g m o le cu l a r b o n d s . C a u s t ic s tr ip p e r s c a n c on on t a i n so so d i u m , ca ca lc lc iu iu m , an an d m a g n e s i u m h y d r o x i d e . C a u s t ic ic s t ri rip p e r s ar ar e r e s t r i ct ct e d t o o i ll- b a s e d p a i n t s b u t w i ll ll n o t w o r k o n o i ll- b a s e d p a in ts th a t a r e p ig m en te d w it h al u m in u m flakes. flakes. This is becau se hyd rogen ga s is g e n e r a te te d w h e n c a u s t ic ic c om om p o u n d s c o m e i n contact with alum inum , thus preven ting the c a u s t i c s t r ip ip p e r f ro ro m p e n e t r a t i n g t h e p a i n t system.
C h e m i c a l s t r ip ip p e r s a r e co co m m o n l y u s e d f o r s m a l l a r e a s w h e r e p o w e r i s no no t a v a i l a b l e , a b r a s i v e a n d w a t e r je je t b l a s t in in g i s n o t econom ically ically feasible, feasible, hose d istance is too g r e a t t o a ch i e v e n e c e s s a r y a i r p r e s s u r e f o r b la s ti n g op er a ti o n s, o r w h er e a cc es sib si b il it y is l im im i t e d . C h e m i ca ca l s t ri rip p e r s ar ar e a l s o u se se d t o m i n i m i ze ze a ir ir b o r n e p a i n t p a r t i cl cl e s fo fo r o r g a n i c p a in ts o r h e a v y -m e ta l b a se d p a in ts (e .g ., l ea d ). I n g e n e r a l , ch ch e m i ca ca l s t r ip ip p e r s m a y b e m e s s y , m a y r e q u i r e r e p e t i t iv iv e a p p l ic ic a t io io n s t o r e m o v e a l l f o r e ig ig n m a t t e r fr fr o m t h e s u b s t r a t e , a n d m a y l e a v e a r e s id id u e o n t h e s u b s t r a t e t h a t r e q u i r e s solvent clean clean ing. There is no su rface c le le a n l i n e s s st st a n d a r d f o r t hi hi s m e t h o d ; h o w e v e r , cleanliness cleanliness can be sp ecified ecified to the r e q u i r e m e n t s o f a co co n s e n s u s su su r fa fa c e p r ep a r a ti o n (e .g ., N A C E 3 / SSPC SS PC -SP6 -S P6). ).
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Chapter VII Environmental Conditions C o l d w e a t h e r , h i g h h u m i d i t y , w a t e r , fo fo g , fr fr o s t , m i s t , r a in in , i ce ce , a n d s n o w a r e s o m e o f t h e e n v i r o n m e n t a l fa fa c t o r s d e t r i m e n t a l t o t h e p e r f or m a n c e o f c o a t in g s . C o a ti n g s s h o u l d b e applied under optimum environmental c o n d i t io io n s , b u t t h e w e a t h e r c an an a b r u p t ly ly c h a n g e . T h e p r e v a i l in in g e n v i r o n m e n t a l ru ru l ee- o fft h u m b i s t h a t e v a p o r a t i o n sh sh o u l d b e o cc cc u r r i n g . C o m m o n s e n s e , t h e m a n u f a c t u r e r ’s ’s i n s t r u c t io io n s , a n d i n d u s t r y p r a c t i ce ce s a p p e a r t o b e t h e m o s t co m m o n l y f o ll o w e d g u i d e l in e s r e g a r d i n g en en v i r on on m e n t a l c on on d i ti ti o n s d u r i n g c o a ti ti n g a p p l i ca ca t i o n a n d t h e c u r i n g p e r i o d . F a il il u r e t o co co n f o r m w i t h e n v i r o n m e n t a l restrictions restrictions resul ts in a variety of ap plication failures.
32. Environmental Factors Affecting Affecting Coatings.—The follow follow ing are five e n v i r o n m e n t a l f ac ac t or or s t h a t r e q u i r e m o n i t o r in in g d u r i n g c o a t in in g a p p l i ca ca t i o n a n d t h e c u r e p e r io d . (Se e a p p e n d ix K for fo r t e s t p r o c e d u r e s o n the factors below.)
(b) Surface Substrate Substrate Temperature.— Temperature.— Reclam Reclam ation specifications specifications require that c o a t in in g s b e a p p l ie ie d w h e n t e m p e r a t u re re s a r e 5 0 d e g r e e s F o r h i g h e r a n d w i t h i n th th e m a n u f a ct ct u r e r ’s ’s u p p e r l i m i t o r a c co co r d i n g t o t h e m a n u f a c t u r e r ’s ’s in in s t r u c t i o n s . T h e m o r e r e st st r i ct ct i v e r e q u i r e m e n t w i ll ll b e f o ll ll o w e d . I n g e n e r a l , i n d u s t r y p r a c t ic ic e r e q u i r e s s u r f a ce ce t e m p e r a t u r e b e t w e e n a b o u t 4 0 a n d 1 25 25 d e g r e e s F . cl a m a t i o n d o e s n o t (c) Relative Humidity.— R e cl specify specify limits for relative relative h u m idity; rather, it s p e c if if ie ie s t h a t t h e c o a t i ng ng b e a p p l i e d w i t h i n t h e m a n u f a ct ct u r e r ’s ’s r e co co m m e n d e d h u m i d it it y r a n g e . G e n e r a l i n d u s t r y p r a c t ic ic e r eq eq u i r es es a m a x im im u m r e l a t iv iv e h u m i d i t y o f a b o u t 8 0 t o 8 5 p e r c e n t, t, except for those coatings coatings th at are less less moisture s e n s it it i v e o r a r e m o i s tu tu r e c u r e d . H o w e v e r , a s a general ru le-of-thu le-of-thu m b, the closer closer to the o p t i m u m r e l a t i v e h u m i d i t y , t h e m o r e l i ke ke l y t o achieve the d esign esign ed serv ice ice life. life. i n t d e t er er m i n es es i f (d) Dew Point.— Th e d e w p o in
(a) Ambient Temperature.— D u r i n g t h e ap plication of coatings, coatings, Reclam Reclam ation specificatio specification n s require that th e air an d su rface temp erature be 50 deg rees F or higher and w i t h i n t h e m a n u f a ct c t u r e r ’s ’s u p p e r t e m p e r a t u re re l im im i t o r a c co co r d i n g t o t h e m a n u f a ct ct u r e ’s ’s instru ction ction s, w hichever is th th e mor e restrictive r e q u i r e m e n t . E x ce ce p t i o n s a r e m a d e fo fo r c o a t in in g s f o r m u l a t e d f o r co co l d w e a t h e r a p p l i ca ca t i o n s . A m b i e n t (a (a i r ) t e m p e r a t u r e i s im im p o r t a n t f o r s u c c e s sf sfu l f il il m f o r m a t i o n a n d c u r i n g . S o m e e p o x y c o a t in in g s a p p l ie ie d b e lo lo w 5 0 d e g r e e s F w i ll ll n o t c u r e , a n d c u r i n g w i ll ll n ot ot p r o c ee ee d e v e n i f temp eratures exceed 50 degrees F at a later time. A g e n e r a l ru ru l ee- o ff- th th u m b i n t h e c o a t in in g i n d u s t r y i s t o a p p l y co co a t i n g s a t a m b i e n t t e m p e r a t u r e s b e t w e e n 4 0 a n d 9 5 d e g r e e s F, F, d e p e n d i n g on on t h e cco o a t i n g m a t e r i a l. l.
m o i s tu tu r e w i ll ll fo fo r m o n t h e f e r r o u s s u b s t r a t e s b y c o n d e n s a t i o n o r i f m o i st st u r e w i ll ll e v a p o r a t e . M o i s t u r e w i ll ll fo fo r m o n f e r r o u s s u b s t r a t e s u r f ac a c e s w h e n t h e d e w p o i n t i s h ig ig h er er t h a n t h e s u r f a c e t e m p e r a t u r e . C o n v e r s e l y , m o i s tu tu r e w i ll ll n ot ot f o r m w h e n t h e s u r f ac ac e t e m p e r a t u r e i s higher than the dew p oint. Dew p oint is a f u n c t io io n o f a m b i e n t t e m p e r a t u r e , s ub ub s t r a t e temp erature, and relative hu midity. All three o f t h e se se e n v i r o n m e n t a l co co n d i t io io n s m u s t b e k n o w n t o d e t e rm rm i n e th th e d e w p o i n t . Reclam Reclam ation specifications specifications requ ire that the f er er r o u s s u b s t r a t e t e m p e r a t u r e b e a m i n i m u m of 5 degrees F higher than the d ew p oint when c o a t in in g s a r e a p p l ie ie d . Th e c o a t in in g i n d u s t r y i m p o se se s t h e s a m e d e w p o i n t r e s t r i ct ct i o n . Reclamation specifications specifications requ ire surfaces t h a t a r e n o t t h o r o u g h ly d r y t o b e h e a t e d o r t h e e n v i r o n m e n t co co n t r o l le le d b y d e h u m i d i fy fy i n g a n d h e a t i n g e q u i p m e n t t o d r i v e o f f m o i st st u r e .
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Guide to Protective Protective Coatings: Coatings: Inspection and Maintenance M o i s t u r e c o n d e n s a t i o n w i ll ll b e g in in w h e n t h e s u b s t r a t e t e m p e r a t u r e i s l es es s t h a n t h e d e w p o in t . To a ll o w fo r p o s s ib l e i n s t r u m e n t a t io n e r r o r o r v a r i a t io io n , a m i n i m u m s a fe fe t y m a r g i n o f 5 d e g r e e s F s u b s t r a t e t e m p e r a t u r e a b o v e th th e d e w p o i n t is is r e g a r d e d a s a g e n e r a l i n d u s t r y requirement. Reclam ation d oes not specify a (e) Wind.— Reclam m a x im im u m w i n d v e lo lo c i ty ty r e s t r i ct ct io io n i n c oa oa t i n g a p p l ic ic a t io io n s . W i n d b e c o m e s a f ac ac to to r w h e n i t
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overcomes the spraying op eration and carries c o a t in in g p a r t i cl cl e s a w a y f r o m t h e i n t e n d e d s u r f a c e . T h i s p r o b le le m i s k n o w n a s a ir ir b o r n e overspray. Airborne oversp ray may result in p r e m a t u r e d r y i n g o f t h e co a t in g b e fo r e reaching the intend ed surface, a lower DFT at t h e s p r a y a p p l i ca ca ti ti o n p o i n t , a h i g h e r D F T d o w n w i n d , o r s p r a y b e i n g ca ca r r i e d t o a d ja ja c e n t v e h i c l e s, s, h o m e s , o r o t h e r s u r f a ce ce s n o t i n t e n d e d t o b e c o a t e d . C o m m o n se se n s e s h o u l d b e u s e d t o av av o i d a i r b o r n e o v e r s p r a y p r o b l e m s .
Chapter VIII Applic Ap plicatio ation n and a nd Curing Cur ing C o a t i n g a p p l i c a ti ti o n i s n e x t i n i m p o r t a n c e a f t e r surface preparation, and accounts for most failure failure s. A coating coating is not a finished p rod uct until it has been successfu successfu lly lly ap plied to the s t ee ee l su su b s t r a te te a n d c u r e d . C o a t in in g p e r fo r m a n c e is a ffe ct e d d u r in g a p p lica li ca t io n a n d c u r i n g b y t e m p e r a t u r e , r e la la t i v e h u m i d i t y , a n d d e w p o i n t . ( Se Se e ch ch a p t e r V II II , “ E n v i r o n m e n t a l Cond itions.”) itions.”) Mixing, num ber of coats and thickness, and ap p lication lication techn techn ique w ill ill also also affect coating perform ance. N ot observing the e n v i r o n m e n t a l r e s t r ic ic t io io n s o r i m p r o p e r a p p l ic ic a t i on on t e c h n i q u e s c a n r e s u l t i n d e f e c t s , p r e m a t u r e f a il u r e , o r r e d u c e d s e r v i ce li fe. fe .
33. Application Application Temperature and and Humidity co n d i t io io n s a r e Restrictions.— E n v i r o n m e n t a l co n o t a l w a y s co co n t r o l la la b l e . W e a t h e r m a y a b r u p t l y ch ch a n g e , a n d c o n d i t i on on s m a y v i o la la t e t h e m a n u f a ct c t u r e r ’s ’s t e m p e r a t u r e a n d h u m i d it it y restrictions. restrictions. Unle ss cond itions itions can be c o n t r o ll ll e d b y d e h u m i d i fy fy i n g , h e a t i n g , o r a comb ination of both , field field ap p lication lication shou ld p r o ce e d o n ly d u r in g fa v o r a b le w e a th e r . C o a t i n g i n h i g h h u m i d i t y a r e a s , su su c h a s t h e i n t e r io io r s o f v a u l t s o r p i p e s , s h o u l d b e p er for fo r m ed on ly w h en th e e n v ir on m en t is c o n t r o ll ll e d b y d e h u m i d i fy fy i n g , h e a ti ti n g , o r b o th th . Reclam Reclam ation specifications specifications provide th e f o ll ll o w i n g t em em p e r a t u r e a n d h u m i d it it y restrictions, restrictions, u nless the m anu facturer’s i n s t r u c t io io n s a r e m o r e s t r i ng ng e n t : •
•
A ir i r a n d s u b st st r at a t e te te m p e r at a t u r es e s sh sh a ll ll b e a b ov e 5 0 d eg r ee s F d u r in g a p p l ic ic a t io io n a n d c u r i n g a n d w i t h in in t h e m a n u f ac ac t u r e r’ r ’s u p p e r t e m p e r a t ur ur e limit. S u r fa f a ce ce s s h aall l b e a m in in im im u m o f 5 d e g r e e s F a b o v e t h e d e w p o in in t t e m p e r a t u r e a t t h e t i m e o f c oa oa t i n g application.
•
R el e l a ti t i ve v e h u m i di d i ty t y ssh h a ll l l b e w i t hi hi n t h e m a n u f a c t u r e r ’s ’s l im im i t s .
34. Coating Layers.— Reclam Reclam ation ty pically pically s p e c if if ie ie s t h e n u m b e r o f c o a t s to to b e a p p l ie ie d i n the coating coating tabul ations. The following following terms p ro v i d e a d es c r ip ti o n o f t he co a t i ng la y e rs : lied (a) Stripe Coat.— Stripe coats are app lied to prepared bare metal edges, boltheads, w e l d s , co co r n e r s , a n d s im im i l a r e d g e s b e f o r e t h e p r i m e co a t is a p p li e d . St r ip e c o at s a r e necessary becau se, as as the coating d ries, tensile tensile forces are created at the ed ges, forcing forcing the c o a t in in g t o p u l l a w a y f r o m t h e e d g e i n b o t h d irections, resulting in a th inner coating at the e d g e . St r i p co co a t s p r o v i d e a n a d d i t i o n a l t h i ck ck n e s s b u i l d u p t o p r e v e n t t h i n , D F T a t edges. ie d (b) Prime Coat.— P r i m e c o a t s a r e a p p l ie o v e r t h e e n t i r e s u r f a ce ce t o b e c o a t e d , i n c lu lu d i n g s t r ip ip e c o a t e d a r e a s . T h e p r i m e c o a t m u s t c o v e r the peak s of of the the surface profile. Th e c o n s e q u e n c e o f n o t c ov ov e r i n g t h e p e a k s is is p i n p o in t r u s t in g .
(c) Intermediate Coat.— I n t e r m e d i a t e c o a ts ts a r e a p p l ie ie d o v e r t h e p r i m e r t o p r o v i d e a d d i t io io n a l p r o t e c t io io n o r t o s e a l th th e p r i m e r . M u l t ip ip l e i n t er er m e d i a t e c o a ts ts c a n b e a p p l ie ie d t o bu i ld u p t h e fil fi l m t h i ckn ck n e ss . (d) Topcoat.— Topcoats or finished finished coats a r e a p p l ie ie d o v e r t h e p r i m e r o r i n t e r m e d i a t e coat for color aesthetics or to protect the u n d e r l in in i n g c o a t in in g m a t e r i a l f r o m s u n l ig ig h t a n d UV light.
(e) Base Coat.— “Base coat” is a term often u s e d t o d e s cr cr i b e a s e lf lf -p -p r i m i n g m a t e r ia ia l a p p l ie ie d i n m u l t i p l e co co a t s. s. T h e te te r m , “ b as as e c o a ts ts , ” i s u s e d i n st st e a d o f “ p r i m e r ,” ,” “ i n t e r m e d i at at e , ” a n d “ t o p c o a t ” b e ca ca u s e a ll ll
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Guide to Protective Protective Coatings: Coatings: Inspection and Maintenance three coats are of the same m aterial. Base Base coats a r e n o t n o r m a l ly ly c o n s id id e r e d s u n l i g h t o r U V resistant. Before ap plication plication , the coating 35. Mixing.— Before m a t e r ia ia l s r e q u i r e m i x i n g t o m a k e th th e p a i n t h o m o g e n e o u s a n d u n i fo fo r m . L iq iq u i d s a n d p i g m e n t s o f d i f fer e n t d e n s i t ie s m a y s e p a r a t e , s e tt tt l e, e, o r f or or m a s k i n w i th th i n t h e s h i p p i n g container. Mixing is to be performed a c c o rd rd i n g t o t h e m a n u f a c t ur ur e r ’s ’s i n s t r u c t io io n s . C o a t i n g s a r e e i t h e r s i n g l e -c -c o m p o n e n t o r m u l ti ti p l e -c -c o m p o n e n t . M o s t m u l t ip ip l eec o m p o n e n t c o a ti ti n g s a r e tw tw o - co co m p o n e n t . E p o x i e s a r e a n e x a m p l e o f a t w o - co co m p o n e n t c o a ti ti n g . T h e y co co n t a i n a r e si si n a n d a h a r d e n e r . T h e c o m p o n e n t s o f a m u l t ip ip l e -c -c o m p o n e n t coating can be in eq ua l prop ortions (e.g., (e.g., 1:1) 1:1) or uneq u al pr op ortions (e.g., (e.g., 1:4) 1:4).. Prop ortions a r e d e t e rm r m i n ed ed b y v o l um um e . C o m p o n e n t s m u s t be b e sh i pp e d i n se p ar a t e co n t a in e r s. R e ga rd l e ss o f th th e p r o p o r t i o n v o lu lu m e fo fo r m u l t ip ip l e c o m p o n e n t m a t e r i al al s , t h e m a n u f a ct ct u r e r w i l l ship one container large enough to hold all the c o m p o n e n t s f o r m i x in in g . T h e f ol ol lo lo w i n g a r e c om om m o n m i x in in g m e t h o d s : •
M an a n u al a l l y pa p a d d l in in g ( t h e m os ost ineffici inefficient ent m ethod ).
•
M e ch c h a ni n i c a ll ll y a gi g i t a ti ti n g or o r p ad a d d lin g .
fa c e 36. Application Method.— O n c e t h e s u r fa s u b s tr tr a t e h a s b e e n p r o p e r l y p r e p a r e d a n d e n v i r o n m e n t a l c o n d i t i o n s a r e w i t h in in s p e c if if ie ie d tolerances, the the ap p lication lication of th e coatin coatin g m a t e r i a l m a y p r o c e e d . T h e r e a r e se se v e r a l e q u i p m e n t c h o i ce ce s f ro ro m t r a n s f e r r in in g t h e c o a ti ti n g f r o m t h e c o n t a i n e r t o t h e s u b s t r a t e . A p p l ic ic a t io io n e q u i p m e n t m a y b e d i c t a t e d b y t h e m a t e r ia ia l ty ty p e a n d t h e s iz iz e o f t h e s u r f a ce ce a r e a . T h e m a n u f ac ac t u r e r ’ s in in s t r u c t i o n s w i ll ll n o r m a l ly ly p r o v i d e t h e p r e fe r r e d a p p li c a tio ti o n m e t h o d fo r s m a l l a n d l a r g e a r e a s. s. The follow follow ing is a description of app lication lication equipment and methods.
(a) Brush.— T h e r e t w o g e n e r a l t y p e s o f br b r u s h e s : w a l l a n d s a s h . T h e y c o m e i n v a r i o u s sizes, shap es, and bristle typ es. For steel s u b s t r a t e s , w a l l b r u s h e s a r e n o r m a l ly ly u s e d f o r sm all areas, repair areas, and crevices or gap s. W a l l o r o v a l b r u s h e s a r e w e ll ll s u i t e d f o r s t r ip ip e coating irregu lar su su rfaces such as ed ed ges, corners, bolthead bolthead s, and similar area s. Sash br b r u s h e s a r e b e t te r s u i t e d f o r co a t in g n a r r o w areas. te n o r p a i n t p a d s h o ld ld m o r e (b) Mitten.— M i t te c o a ti ti n g t h a n a b r u s h , b u t t h e y r e q u i r e a tr tr a y . T h i s a p p l i ca ca t i on on m e t h o d i s u s e d f or or s m a l l, l, i r r e g u l a r ly ly s h a p e d s t r u c t u r e s s u c h a s handrails. Rollers consist of tw o gene ral (c) Roller.— Rollers
•
Sh a k i n g .
•
Bo x in in g (r ( r e qu q u i re r e s p ou o u r in i n g th t h e m a t er e r ia ia l from the original shipping container i n t o an an e m p t y c on on t a i n e r an an d r e p e a t in in g the process several times). It is is most o f t e n u s e d f o r s in in g l e - co co m p o n e n t , m o i s tu tu r e - c u r e d m a t e r i a l s. s.
I f t h e m a n u f a c t u r e r r e c om om m e n d s t h i n n e r s , t h ey ey a r e a d d e d i n t he he r e c o m m e n d e d a m o u n t s d u r i n g m i x i n g . A f te te r m i x i ng ng , so so m e m u l t i p l e comp onen t ma terials terials requ ire a 10- to 3030m i n u t e i n d u c t io io n p e r i o d t o a ll ll o w c h e m i c a l reactions to begin before app lication. lication.
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p a r t s : co v e r a n d c o r e. T h e co v e r i s t h e s e ct io n t h a t a p p l ie ie s th th e c o a t i n g a n d w i ll ll v a r y i n d i a m e t e r , le le n g t h , f a b r i c t yp yp e , a n d f ib ib e r l e n g t h (nap ). Rollers Rollers are norm ally us ed for large large flat flat are as (horizo (horizo nta l and ver tical tical surfaces) tha t are t o o l a r g e fo fo r b r u s h a p p l ic ic a t io io n o r w h e r e o v e r s p r a y c a n n o t b e t o le le r a t e d . T h r e e b a si si c t y p e s o f r o l le le r s a r e d i s c u s s e d b e l o w .
Pipe roller.— Pipe rol lers consists of tw o or m o r e r o l le le r s h i n g e d t o g e t h e r t o c o n f or or m t o a c u r v e d s u r f a c e s uc uc h a s a s m a l ll- d i a m e t e r p i p e . rollers have an e xtra Fence ro ller.— ller.— Fence rollers l o n g n a p s o t h a t w h e n a p p l y i n g a c o a t in in g f r o m
Ap pli cati on an d Cu rin g o n e s i d e o f a h u r r i c a n e o r w i r e fe fe n c e , t h e l o n g n a p w i ll ll co co v e r b o t h s i d e s .
Pressure roller.— Pressu re rollers feed a p e r fo r a t e d c o r e w it h a s t e a d y s u p p ly o f c o a t in in g m a t e r i a l f r o m a p r e s s u r i z e d t a n k . (d) Conven tional Spray (applied cold cold or ho t).— t). — ir c o m p r e s s o r , an an o il il Equipment.— A n a ir and w ater separator, a pressure tank (pot) or p u m p , a ir a n d flu fl u i d h o s es , a n d a s p r a y g u n a r e need ed. For hot spray, a heater is add ed to heat th e m aterial to abou t 150 to 160 160 degrees F. is Working p rinciple.— rinciple.— C o m p r e s s e d a i r is i n t r o d u c e d i n t o t h e c o a t in in g s t r e a m a t t h e s p r a y g u n n o z z l e , t h u s b r ea ea k i n g d o w n t h e co co a t i n g i n t o t i n y d r o p l e t s ( co co a t i n g a t o m i z a t io io n ) a n d p r o p e l lin li n g t h e c o a t i n g t o t h e s u r f a ce s u b s t r a t e .
Equipment.— T h i s m e t h o d r e q u i r e s a h i g h v o lu lu m e a i r s u p p l y (c (c om om p r e s s e d a i r o r tu tu r b i n e generator), a m aterial sup ply system, and an HVLP spray gun. lu m e o f a i r Working p rinciple.— rinciple.— A h i g h v o lu a t o m i z e s t h e c o a t in in g m a t e r i a l a t a l o w p r e s s u r e a n d t r a n s f e r s t h e a t om om i z e d c o a t in in g p a r t i c le le s t o the substrate by low p ressure.
Ad van tage s.— T h e m e t h o d h a s a b e t t e r tran sfer effici efficiency ency (less (less ma terial lost) lost) than h as t h e co co n v e n t i o n a l s p r a y m e t h o d , a n d b o u n c e ba ck an d ov er sp ra y a re r ed u c ed . Th e H VL P s p r a y g u n i s m o r e c o n t r o l la la b l e t h a n o t h e r s p r a y g u n s . T h e m e t ho ho d w o r k s w e l l w i t h high -solids -solids coatin coatin g ma terial. terial.
Disadvantages.— T h e c o v e r a g e o r p r o d u ct io n r a t e is le s s t h a n w it h o t h e r s p r a y methods, and the method may not atomize certain coating m aterials.
Ad van tage s.— T h e c o n v e n t i o n a l s p r a y m e t h o d p r o v i d e s m o r e f in in e l y a t o m i z e d c o a t in in g p a r t ic le s, r e su l t in g i n a sm o o th e r a n d m o r e u n i fo fo r m f i lm lm . L ar ar g e a r e a s c a n b e co co v e r e d i n a r e l a t i ve ve ly ly s h o r t t i m e . O p e r a t o r c o n t ro ro l o f t h e s p r a y g u n i s e xc xce l le le n t . Th e s p r a y g u n h a s a h i g h d e g r e e o f v e r s a t i l it it y r e g a r d i n g d i ff ff e re re n t c o a ti ti n g m a t e r i al al s an an d s p r a y p a t t e r n s . S tr tr i p i n g c a n b e a cc cc o m p l is is h e d b y t h i s m e t h o d . For hot spr ay ap plication plication , the the v iscosity iscosity is l o w e r e d t o i m p r o v e a p p l ic ic a t io io n o r t o m e e t minimum material temperature.
im i t ed ed t o s m a l l e r Uses.— T h i s m e t h o d i s l im a r e a s o r s u r f a ce ce s t h a t co co n t a i n n u m e r o u s recesses.
(f) Airless Airless Spray (Applied Cold or or Hot).— Equipment.— T h i s m e t h o d r e q u i r e s a p ow er so u r ce (e le ct r ic m ot or or ai r c o m p r e ss ss o r ) , a h y d r a u l i c p r e ss ss u r e p u m p , a high-pressure fluid hose, and an airless spray g u n w i th th a s a f e t y e x te te n s i o n t i p . io n o f t h e Working p rinciple.— rinciple.— A t o m i z a t io
Disadvantages.— T h e c o n v e n t i o n a l s p r a y m ethod u ses large amou nts of air. Con sequen tly, transfer effici efficiency ency is low (mater ial is is lost) lost) becau se of bou nce back ( r e bo b o u n d ) a n d o v e r s p r a y . T h e r e b ou ou n d m a k e s it d ifficult ifficult to coat corners an d crev ices. ices. This m e t h o d i s n o t g e n e r a l l y s u i ta ta b l e f o r h i g h - b u i l d c o a ti ti n g m a t e r ia ia l s w i t h o u t e x c e ss ss i v e t h i n n i n g .
Use.— T h i s m e t h o d i s u s e d o n n e a r l y a ll ll R e cl cl a m a t i o n s t r u c t u r e s w h e r e o v e r s p r a y i s n o t a c o n c e r n. n. T he he h o t s p r a y m e t h o d i s u s e d d u r i n g c o o le le r w e a t h e r . (e) High-Volume, Low-Pressure Low-Pressure (HVLP) Spra y.—
c o a t in in g i s a c h i e v e d b y f o r c in in g t h e m a t e r i a l t h r o u g h a s m a l l or or i f ic ic e u s in in g h y d r a u l i c p r e s s u r e r a th e r t h a n a ir p r e s su r e . T h e h ig h p r e s s u r e p u m p m u l t ip l ie s t h e in p u t p r e ss u r e by b y a m i n i m u m fa ct o r o f 3 0, s u c h t h a t t h e o u t p u t p r e s su su r e a t t he he s p r a y g u n p r o d u c e s p r e s su r e s u p t o a b o u t 6,0 00 p s i. T h e sp r a y g u n has a fixed orifice orifice size and va riou s fixed fixed ang les t o a l lo lo w s e v e r a l s p r a y f a n p a t t e r n s a n d t h i ck ck n e s s e s t o b e a p p l i e d w i t h t h e s a m e a m o u n t o f m a t e r i al al . is m e t h o d p r o v i d e s Ad van tage s.— T h is g r e a t e r c ap ap a c it it y f or or a p p l y i n g h i g h b u i l d c o a t in in g s , g r e a t er er s u r f a c e p e n e t r a t i o n b e c a u s e o f h i g h a p p l i c a ti ti o n p r e s s u r e s , h i g h c o v e r a g e o r
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Guide to Protective Protective Coatings: Coatings: Inspection and Maintenance p r o d u c t io n r a t es , t h e ca p a c it y to a to m iz e h ig h v i s co co s it it y m a t e r i a l, l, r e d u c e d o v e r s p r a y a n d b ou n ce b a ck , a n d th e p ot en ti a l for fo r r ed u ce d oi l a n d w a t e r co co n t a m i n a t io io n .
fo r Uses.— T h i s m e t h o d i s s u i t a b l e fo m e d i u m t o la la r g e s u r f a ce ce a r e a s w h e r e o v e r sp s p r a y a n d r e b ou o u n d a r e n o t a c o n ce ce r n .
(h) Electrostatic Electrostatic Spray.— Disadvantages.— T h i s m e t h o d d o e s n o t p r o d u c e th e f in e l y a t o m i z e d c o a t i n g p a r t i cl e s t h a t a r e p r o d u c e d b y c o n v e n t i o n a l sp sp r a y , a n d it is is not suited for high qu ality finishes. The operator has less control of the spray gu n than w i t h t h e co n v e n t io io n a l s p r a y m e t h o d , a n d t h e r e i s a h i g h e r p o t e n t i a l f o r a p p l ic ic a t io io n d e f e c t s t h a n w i t h t h e c on on v e n t i on on a l sp sp r a y m e t h o d . T h e h i g h p r e s su su r e s a r e c a u s e f o r s a f e ty ty c o n c e r n s .
Uses.— T h i s m e t h o d i s b e s t s u i t e d t o la r g e s u r f a ce ce a r e a s w h e r e o v e r s p r a y i s n o t a c o n c e r n . It is is u sed on n early all Reclam Reclam ation stru ctures. T h e h o t s p r a y m e t h o d i s u s e d f o r a p p l ic ic a t io io n d u r i n g c o o le le r w e a t h e r .
Equipment.— T h e e q u ip ip m e n t u s e d i n t h e electrostatic spray m ethod is similar to conven tional, airless, and air-assisted air-assisted spr ayer e q u i p m e n t , e x ce ce p t t h a t a n e l e ct ct r o s t a t ic ic , h i g h v o l t a g e s u p p l y is is r e q u i r e d . in g s Working p rinciple.— rinciple.— A t o m i z e d c o a t in a r e a p p l ie ie d t o t h e s u b s t r a te te b y c o n v e n t io io n a l , airless, airless, or or air-assisted air-assisted spra y equip m ent, wh ich i s c on on n e c t e d t o a n e l e ct ct r o s t a ti ti c p o w e r s o u r c e . The coating mate rial is positively charged , a n d t h e s u b s t r a t e i s ne ne g a t i v e l y c h ar ar g e d (conv (conv entional electric electrical al theory). Sprayed , p o s it iv e l y c h a r g e d , a t o m i z e d c o a t i n g p a r t i cl e s a r e a t t r a c t e d t o n e g a t i v e ly ly c h a r g e d s u b s t r a t e .
(g) Air-Assisted Airless Spray.— Air-assisted a i r le le s s s p r a y a p p l ic ic a t io io n e q u i p m e n t w a s d e v e l o p ed e d t o c o m b i n e s om o m e o f t he he a d v a n t a g e s o f c o n v e n t i o n a l a n d a i r le le s s s p r a y s y s t e m s i n t o o n e s y st st e m .
Equipment.— T h i s m e t h o d r e q u i r e s a hyd rau lic pressu re pu m p (500 to 1,000 1,000 psi), hoses , an ai r comp ressor (10 (10 to 15 ps i), i), and a spray gun. io n o f Working p rinciple.— rinciple.— T h e a t o m i z a t io the coating is sim sim ilar to the atom ization of the a i r l e ss ss s p r a y e r , b u t t h e p r e s s u r e i s lo lo w e r a t t h e o r i fi fi c e o f t h e s p r a y g u n w i t h t h i s m e t h o d , n o r m a l ly ly a t a b o u t 10 10 p s i .
Ad van tage s.— T h is is m e t h o d p r o v i d e s m o r e finely finely atom ized coating p articles, articles, a lower p o t e n t i a l f o r a p p l ica ic a t io n d e fe c ts , a n d b e t t e r operator control of the spray gu n tha n the airless airless meth od . Also, transfer effic efficiency iency is b e t te r th a n w it h t h e co n v e n t io n a l s p r a y e r .
Ad van tage s.— The e lectrostatic spray m e t h o d i s ca ca p a b l e o f a p p l y i n g c o a ti ti n g s t o o d d s h a p e s a n d a r o u n d c o r n e r s , a n d o v e r sp sp r a y a n d r e b o u n d m a t e r ia ia l in in c o n f in in e d s p a c e s a r e r e a t t r ac ac t e d t o t h e s u b s t r a t e . T h i s m e t h o d h a s a h i g h t r a n s f e r e f fi fi ci ci e n c y r a t e an an d p r o d u c e s a u n i f o r m f in i s h . th e Disadvantages.— T h e w i n d m a y c a r r y th c o a ti ti n g m a t e r i al al a w a y , th th e m e t h o d a ll ll o w s o n l y o n e t h i n c o a t , t h e c o v e r a g e a n d p r o d u c t io io n r a t e a r e l e ss ss t h a n w i t h th th e o t h e r s p r a y m e t h o d s , a c o n d u c ti ti v e c o a t in in g f or or m u l a t i on on i s u s u a l l y r e q u i r e d , t h e m e t h o d i s u n s u i t a b l e fo fo r l a r g e s t r u c t u r e s , a n d t h i s m e t h o d p r e s en en t s a p o t e n t ia l e le ct r ica l s h o ck h a z a r d .
Uses.— T h i s m e t h o d i s s u i t e d t o s m a l l a r e a s b e h i n d c o r n e r s , r e ce ce s s e d a r e a s , i r r e g u l a r areas, or areas that cannot be coated by c o n v e n t i o n a l -t -t y p e a p p l i c a t io io n e q u i p m e n t .
(i) Plural Component Spray.— T h i s s p r a y Disadvantages.— T h i s m e t h o d i s n o t s u i t e d for high-qua lity lity finishes finishes becau se atomiza tion a p p r o a c h e s b u t d o e s n o t e q u a l a t o m i z a t io io n w i th th t h e c o n v e n t i o n a l sp sp r a y e r m e t h o d . T h is is m e t h o d p r o d u c e s o ve v e r sp sp r a y a n d r e b o u n d .
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a p p l ic ic a t io io n m e t h o d i s t h e m o s t c o m p l e x o f t he he spray equipment group and should be used by a p p l ic ic a t o r s w h o a r e t r a in in e d a n d c e r t if if ie ie d b y t h e c o a t in in g m a n u f a c tu tu r e r . T h i s a p p l ic ic a t io io n method is commonly used to apply two or
Ap pli cati on an d Cu rin g m o r e c o m p o n e n t m a t e r i a ls ls (h (h e n c e , t h e t e r m “plur al”) such as polyurethanes and polyurea s that can hav e an extremely short set period (3 to 30 second s for for m aterial to h ard en).
a c co co m p l is is h e d u s i n g b r u s h , r o l l e r s , s p r a y e r s , o r a combinat ion of these these tools; how ever, spray e q u i p m e n t i s t h e m o s t c om om m o n l y u s e d m e t h o d . Se v e r a l “ g o o d p r a c t i ce ce ” t ip ip s f o r s p r a y a p p l ic ic a t io io n s a r e d i s cu cu s s e d b e l o w .
Equipment.— T h i s m e t h o d r e q u i r e s a p r o p o r t io n in g p u m p , a m i x m a n i fo ld , a m ix er , a spray gu n, material sup ply containers, and a solvent pu rge (fl (flus us h) container. Mater ial can b e a p p lie li e d b y c o n v e n t io n a l, a ir le ss , o r a ir a s s is is t e d s p r a y e q u i p m e n t , b u t s p e c ia ia l s p r a y g u n s a r e re r e q u i r ed e d . T h e eq eq u i p m e n t a n d m a t e r i a l s m a y b e h e a t e d t o d e c r e a s e t h e cu cu r e p e ri o d a n d a llo w fo r cl e an u p .
Working p rinciple.— rinciple.— I n d i v i d u a l c o m p o n e n t s a r e m i x e d t h r o u g h a m e t er er i n g s y st st e m t h a t i n c lu lu d e s a p r o p o r t i o n i n g p u m p , i f m i x r a t i o s a r e o t h e r t h a n o n e - to to - o n e , a n d d e l i v e r e d a t t h e sp sp r a y g u n o r a t t h e s p r a y t ip ip . T h i s m e t h o d e li li m i n a t e s p r e m i xi xi n g i n a p re ss u r e p ot . is Ad van tage s.— W i t h t h i s m e t h o d , i t is p os s i b le t o a p p l y h i g h -b u i ld , h i g h -v i sc o s it y m a t e r ia ia l s in in o n e p a s s , e l im im i n a t e l im im i t e d p o t l if if e , a n d m a y p r o v i d e r e d u c e d c u r e t i m e s .
Disadvantages.— T h i s m e t h o d r e q u i r e s p r e cis e p r e s e tt in g o f p r o p o r t io n i n g a n d t e m p e r a t u r e sy sy s t e m s . I t r e q u i r e s im im m e d i a t e a n d t h o r o u g h c le le a n i n g o f e qu qu i p m e n t a f t er er u s e t o p r e v e n t m a t e r i al al fr fr o m s e tt tt i n g u p . I t i s imp ractical for sma ll jobs; jobs; it requ ires trained o p e r a t o r s f a m i l i a r w i t h t h e s p e c i fi fi c e qu qu i p m e n t and m aterial to be used .
(a) Pot Pressures.— T h e p r e s s u r e p o t should hav e two pressure gau ges: one for pot p r e s su r e a n d on e fo r a t o m i z a t io n o f t h e c o a t in in g m a t e r i a l . T h e p r e s s u r e p o t r e g u l a t o r s h o u l d p r o v i d e s u f fi fi c ie ie n t p r e s s u r e t o m o v e c o a t in in g m a t e r i a l t h r o u g h t h e h o s e t o t h e s p r a y g u n . Th e a t o m i z a t io io n p r e s s u r e r e g u l a t o r shou ld be set high enou gh to atomize the coating mater ial. ial. A setting that is is too low w ill c a u s e t h e m a t e r i a l t o c lu lu m p o r p o s s ib ib l y c lo lo g t h e sp sp r a y g u n . ir (b) Air Compressor.— C o m p r e s s e d a ir s h o u l d f l o w a t a s te te a d y r a t e . P u l s a t io io n o f m a t e r i a l f r om om t h e s p r a y g u n n o r m a l ly ly i n d i c a t e s an inadequate air supply. sp r a y g u n (c) Spray Gun Technique.— T h e sp s h o u l d b e h e l d p e r p e n d i c ul ul a r t o an an d a b o u t 1 8 i n c h es es a w a y f ro ro m t h e s u b s t r a t e . T h is is d i s t a n c e m a y v a r y s l ig ig h t l y w i t h d i f fe fe r e n t s p r a y a p p a r a t u s . A n g l i n g , t i lt lt i n g , o r h o l d i n g t h e g u n t o o c lo lo s e o r t o o f a r a w a y c o u l d c a u s e t h e c o a ti ti n g t o s a g o r d r y b e f o r e h i t ti ti n g t h e s u r f a c e . The spray pattern should overlap the previous p a ss b y a p p r ox i m a t e l y 5 0 p e r c e n t , a nd t h e stroke length of each pass should be b etween 18 to 36 inches. The ap p licator licator shou ld m ake a p a ss o f t h e sp r a y g u n b y m o v in g th e ar m a n d bo b o d y , r a t h e r t h a n r o t a t i n g t h e w r i s t t o fan fa n t h e gun.
suita ble for for large surfaces that Uses.— It is suita a r e s u b j e ct ct t o b u r i a l, l, i m m e r s io io n , a n d c h e m i c a l e x p o s u r e s r e q u i r in in g t h i ck ck b a r r i e r c o a t i n g material.
37. Application Technique.— Reclamation d o e s n o t s p e c i f y t h e p r o c e d u r e o r t ec ec h n i q u e t o a p p l y th th e c o a t in in g . R ec ec la la m a t io io n r e q u i r es es o n l y t h a t t h e c o a t i ng ng b e a p p l i e d i n a c co co r d a n c e w i t h the manufacturer’s instructions. These i n s t r u c t io io n s a r e p r o v i d e d i n t h e m a n u f a c t u r e r ’s ’s a p p l ic ic a t io io n s h e e t . T h e a p p l ic ic a t io io n t e c h n i q u e u s e d b y t h e a p p l i c a to to r w i ll ll v a r y s li li g h t ly ly w i t h t h e t y p e o f e q u i p m e n t and m aterial. Most coating coating jobs jobs are
38. Drying, Recoating, Recoating, and Curing.—D r y i n g a n d c u r i n g a r e n o t i n t er er c h a n g e a b l e t e r m s a s they relate to coatings. SSPC defines cure as, “ T h e p r o c e s s o f ch ch a n g i n g t h e p r o p e r t i e s o f a p a i n t fr o m i ts li q u i d s t a t e in t o a d r y , s ta b l e , solid solid p rotective fil film m by ch em ical ical reaction reaction w ith o x y g e n , m o i s t u r e , o r c h e m i c a l a d d i t iv iv e s , o r b y t h e a p p l ic ic a t io io n o f h e a t o r r a d i a t io io n . ” Accordin g to this de finition, finition, coat coat ings t hat form p r o t e ct iv e f ilm s w it h o u t ch e m ic a l r e a c tio ti o n d o n o t c u r e , b u t o n l y d r y t o f or or m a fi fi lm lm . D r y i n g i s t h e l o s s o f so so lv lv e n t o r w a t e r , a n d t h e p r o c e s s m a y o r m a y n o t fo fo r m a p r o t e ct ct i v e f il il m . C u r i n g w i ll ll al al w a y s p r o d u c e a p r o t e ct ct i v e fi fi lm lm .
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Guide to Protective Protective Coatings: Coatings: Inspection and Maintenance O n c e t h e c o a t i ng ng h a s b e e n a p p l ie ie d , t h e inspector can d o little, little, excep excep t to p rotect new ly c o at at e d s u r f a c es e s f ro ro m b e in in g d a m a g e d a n d n o t e t e m p e r a t u r e a n d h u m i d it i t y d u r in in g t h e cu cu r i n g p e r io d to en su r e th a t p r o p e r cu r e is o b ta in e d . M a n u f a c t u r e r ’s ’s i n s tr tr u c t io io n s m a y l i st st a v a r i e t y o f t im im e p e r i o d s f o r d r y i n g , r e co co a t i n g , a n d c u r i ng n g a t v a r i o u s t e m p e r a t u r e a n d h u m i d it it y c o m b i n a t i o n s . T h e s e ti ti m e p e r i o d s a r e d i s cu cu s s ed ed b e lo lo w . is t h e p e r i o d w h e n a (a) Drying.— D r y i n g is c o a t e d i te te m c a n b e m o v e d o r w h e n i t ca ca n a c ce ce p t t r a f f ic ic w i t h o u t d a m a g i n g t h e c o a t in in g b e fo r e fu l l c u r e a t a r efe ef e r e n ce d t e m p e r a t u r e a n d h u m i d i t y . M o s t m a n u f a ct ct u r e r ’s ’s p ro ro d u c t d ata sheets refer to to d rying tim es as “tack free,” free,” “to tou ch,” “to hand le,” le,” or, “to stack” stack” (to stack items one on top of an other , e.g., e.g., pipe s t a ck ck i n g ) , m e a n i n g t h e t i m e b e t w e e n a p p l ic ic a t io io n a n d w h e n t h e s u r f a c e is is t a c k f r e e o r d r y e n o u g h t o t o u c h , t o h a n d l e , o r t o st st a c k . Reclam Reclam ation sp ecific ecifications ations consid er a coating t o b e d r y “ w h e n i t ca ca n n o t b e d i s t o r t ed ed o r r e m o v e d b y e x e r t i n g s u b s t a n t i a l, l, b u t l e s s t h a n m a x i m u m , p r e s s u r e w i th th t h e t h u m b a n d t u r n i n g t h e t h u m b t h r o u g h 9 0 d e g r e e s in in t h e p la n e o f t h e co a ti n g fil m .” referred to as “to (b) Recoating.— This is also referred r e co co a t ” o r “ r e c o a t w i n d o w . ” T h i s i s t h e t i m e p e r io d w h e r e a p r e v i o u s c oa t in g c a n r e ce iv e a n i n t e r m e d i a t e c o a t o r a t o p c o a t a t a r e f e r e n c ed ed
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t e m p e r a t u r e a n d h u m i d i t y . W h e n t h e r e co co a t w i n d o w h a s b e e n e x ce ce e d e d , t h e co co a t i n g s u r f a c e m a y r e q u i re re f u r t h e r s u r fa fa c e p r e p a r a ti o n fo r w h i ch m o s t m a n u fa ct u r e r ’s recomm end abrad ing the surface or solvent a p p l ic ic a t io io n o r b o t h . R e co co a t w i n d o w s v a r y w i d e l y , fr o m a f e w m i n u t e s t o a m o n t h o r l on on g e r , d e p e n d i n g o n t h e t y p e o f c oa oa t i n g m a t e r i a l. l. I f t e m p e r a t u r e a n d h u m i d i ty ty a r e n o t s h o w n o r a r e o u t s i d e t h e l i s te te d v a l u e s o n t h e manufacturer’s instructions, the coating m a n u f a c t u r e r sh sh o u l d b e co co n s u l t e d . Reclam Reclam ation sp ecifications ecifications specify the m a n u f ac a c tu t u r e r ’s ’s r e c o m m e n d e d r e co co a t w i nd nd o w be b e c a u s e r e c o a t w i n d o w s v a r y g r e a t l y w i t h m a t e r ia ia l ty ty p e . is the necessary tim e period (c) Curing.— This is a t a r e fe f e r en en c e d t e m p e r at at u r e a n d h u m i d it it y c o m b i n a t i o n t o a l lo lo w t h e c o a t in in g t o c o m p l e t e t h e c h e m i ca ca l r e a ct ct i o n a n d t o a c h i e v e s t r u c t u r a l integrity so that it will be ready for th e i n t e n d e d s e r v i c e e xp xp o s u r e . E xc xc e ss ss i v e m o i s t u r e a n d l ow o w o r h i g h h u m i d i ty ty o r t e m p e r a t u r e c a n s t o p o r r e t a r d t h e c u r i ng ng p r o c es es s . M o s t m a n u f ac ac t u r e r ’s ’s i n s t r u c ti ti o n s h e e t s p r o v i d e i n f o r m a t i o n f or or c u r e t i m e a n d c u r e t i m e t o i m m e r si si o n . C u r r e n t l y , th th e r e i s n o a l l -e -e n c o m p a s s in in g m e t h o d t o d e t e r m i n e i f a c o a t in in g h a s c o m p l e t el el y cu cu r e d .
Chapter IX Field Inspection and Testing Field insp ection and testing is necessary to e n s u r e c o a t in in g p e r f or or m a n c e a n d t o v e r i fy fy spec ification fication acceptan ce. Field Field inspe ction ction and t e s t in in g a r e p e r f or or m e d i n t h e f o l lo lo w i n g c oa oa t i n g areas: (1) surface prep aration, (2) (2) wet paint, ( 3) 3) h a r d e n e d p a i n t , a n d ( 4) 4) d e s t r u c t i v e t e s ti ti n g .
39. Surface Preparation Preparation Tests.— Tests.—Th e f o ll ll o w i n g t e s t s a r e pe pe r f o r m e d o n p r e p a r e d sur faces faces before coating ap plication plication s and ar e in in a d d i t i o n t o t h e p h o t o g r a p h i c st st a n d a r d s (s (s e e chap ter VI, VI, su su bsection bsection 29, “Photog rap hic I n sp sp e ct ct i on on S ta ta n d a r d s ” ). ).
(a) Testing for Chlorides on Prepared Solub le salts, salts, esp esp ecially ecially the ch loride Surf a ces. — Solub ion, if left left on p rep ared surfaces, can can cau se coatings to blister. If chlorid chlorid e conta m ination is suspected, Reclamation specifications require t e s t in in g t o d e t e r m i n e t h e p r e s e n c e a n d concentrat ion of chlorid e ions after after th e surface p r e p a r a ti o n o f p r e v io u sly co a te d m e ta lw o r k . ( Se Se e ap ap p e n d i x L f o r p r o c ed ed u r e s . ) I f N A C E 5/ SSPC-SP12 SSPC-SP12 surfa ce pre p aration is spe spe cifi cified ed , t h e s t a n d a r d r e q u i r e s t e s t in in g f o r so so l u b l e s a l t s. s. F o r i m m e r s i o n s e rv rv i c e e x p o s u r e , t h e acceptan ce criteria criteria for chlorides is 7 m i cr cr o g r a m s p e r s q u a r e c e n t i m e t e r o r l e s s. s.
T h e p u r p o s e o f t h e s u r f a c e p r o f i le le i s t o p r o m o t e a d h e si o n o f t h e c o a t i n g t o t h e substrat e. Ab rasively blasting a su rface i n c r e a s es es t h e s u r f a c e a r e a , t h u s p r o d u c in in g a g r e a t e r a r e a fo fo r c o a ti ti n g a d h e s i o n . A d h e s i o n s t r en en g t h i s p r i m a r i l y a ch ch i ev ev e d b y i o n i c b on d i n g b e tw e en t h e co at in g an d t h e substra te. Intercoat ad hesion is achieved chiefly chiefly by covalent covalent bon d ing. In gen eral, thick c o a ti ti n g s r e q u i r e a d e e p e r p r o fi fi le le t h a n t h i n coatings. There is is an an op timu m sur face face profile profile d ep th for for the specified specified coating m aterial. If a p r o f ile is t o o sh a l lo w , t h e c o a ti n g m a y n o t achieve prop er adh esion esion . If a sur face face profile is t o o h i g h , t h e c o a t in in g m a y n o t c ov ov e r t h e p r o fi fi le le p ea k s, re su lt i ng i n p in p oi n t ru st i ng . Th e m a n u f a c t u r e r ’s ’s p r o d u c t d a t a s h e e t r e c om om m e n d s t h e s u r f a c e p r o f i le le f or or e a c h specific specific coating prim er. T h e p r o f il il e m a y b e m e a s u r e d w i t h a n y o f t he he following: •
S u r fa f a ce ce p r of o f i l e co c o m p ar a r at a t or or
•
D ia i a l su s u rf r f a ce ce p ro r o fi fi l e g au a u ge ge
•
S p ri r i n g m ic i c r o m et e t er er an a n d r e p li li c a i m p r e s s io io n t a p e
(b) Surface Profile Profile and and Adhesion.— Surface p r o f ile (o r a n c h o r p a t t e r n ) i s t h e t o p o g r a p h y o f the finished finished , abrasively blasted surface. When v i e w e d p e r p e n d i cu cu l a r t o t h e s u r f a ce ce p l a n e , ja g g ed p e ak s a n d v a ll e y s c a n b e o b se rv e d . Various peak heights and valley dep ths can be a c h i e v e d b y t h e t y p e a n d s i z e o f t h e a b r a s iv iv e m aterials used. Surface profile is is classif classified ied by d e p t h a n d t e xt xt u r e p r o d u c e d . D e p t h i s t h e m e a s u r e m e n t o f t h e a v e r a g e d i s t a nc nc e b e t w e e n t h e p e a k s a n d t h e v a l l ey ey s . T ex ex t u r e i s t h e a n g u l a r fi fi n i sh sh e d a p p e a r a n c e o f t h e p e a k s a n d v a l le le y s , r a n g i n g fr fr o m j a g g e d t o r o u n d e d . A ja g g e d t e xt u r e w ill il l n o r m a lly ll y p r o d u c e b et te r adhesion.
R e cl cl a m a t i o n s p e c i f ie ie s t h e s p r i n g m i cr cr o m e t e r a n d r e p l i ca ca im im p r e s s io io n t a p e m e t h o d u s in g N A C E R P 02 87 , “ St a n d a r d R e co m m e n d e d Practice for Field Field M easu rem ent of Surface Surface Profile of Abrasive Blast Blast Cleaned Steel Surfaces Using a Rep lica Tape.” (See (See a p p e n d i x M f o r th t h e p r o c e d u r e .) .) Some old er versions of Reclamation Reclamation specifications specifications sp ecify ASTM D 4417, 4417, “Stand ard T e st st M e t h o d s fo fo r F ie ie l d M e a s u r e m e n t o f Surface Profile of Blast Blast Cleaned Steel,” Steel,” me thod C. Essentially, Essentially, NA CE RP 0287 0287 and ASTM D 4 41 41 7 ar ar e e q u i v a le le n t , p r o v i d e d t h a t t h e c o r r e ct ct m i l r a n g e r e p l ic ic a t a p e i s u s e d .
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Guide to Protective Protective Coatings: Coatings: Inspection and Maintenance D u r i n g i n s p e c t i on on s , p r o t e ct ct i v e g l o v e s s h o u l d be b e w o r n t o a v o i d c o n t a m i n a t in g t h e f in i s h e d p r e p a r e d su r fa ce w it h o il a n d sa lt p e r sp ir a ti o n . Wh ere foot traffic traffic is is un avoi dable, such as w ithin pipe inte riors, pl astic astic slipc slipc over booties a r e r e c om om m e n d e d . ( c) Dust.— Use clear celloph celloph ane tap e (office (office v a r i e t y ) t o d e t e r m i n e a m o u n t o f d u s t fr fr o m a b r a s i v e b l a s ti ti n g a n d o t h e r s o u r c e s t h a t h a s n o t b e e n b lo lo w n o r v a c u u m e d o f f. f. P r e s s t h e tap e on the su rface, rface, peel off, off, an d v isu isu ally o b s e rv rv e t h e a m o u n t o f d u s t t h a t st st i ck ck s t o t h e t a p e . C l e a n t h e t e s t a r e a w i t h a c e t o n e or or a l co co h o l t o r e m o v e t a p e a d h e s i v e fr fr o m p r e p a r ed s u r fa ce . Th e te st ta p e sh o w in g th e d u s t p a r t ic ic le le s ca ca n b e d o cu m e n t e d b y a p p l y i n g it to the d aily insp insp ection ection r ep ort or anoth er field field report.
40. Wet Film Film Thickens.— Thickens.— R e cl cl a m a t i o n d o e s n o t r e q u i r e t e s ti ti n g t h e w e t f il il m t h i c k n e s s ( W F T) T) . W F T is is m e a s u r e d i n a c co co r d a n c e w i t h ASTM D 4414 4414.. (See (See ppe nd ix N for the the p r oc ed u r e.) e. ) H ow ev er , i t i s a u se fu l m e a s u r e m e n t f or or t h e f ol ol lo lo w i n g p u r p o s e s: s: •
T o v er e r i fy fy th th a t a co co n s is i s te te n t th t h i ck ck n eess s i s be in g a p p li ed . A co n si st e n t W FT s h o u l d d r y i n to to a n e v e n D F T .
•
T o p re r e d i ct c t t he h e re re ssu u lt l t in in g D F T. T. S o m e m a n u f a ct ct u r e r ’s ’s i n s t ru ru c t io io n s s t a t e a w e t film film thickness coating ap plied at a c er er t a i n n u m b e r o f m i l s w i l l r e su su l t in in a p r e d e te r m in e d D FT . Fo r ex a m p le , a c o a ti ti n g a p p l i ed ed 1 0 m i ls ls w e t w i ll ll r e su su l t in a DFT of 8 mils. H ow ever, if the m a n u f a c tu tu r e r ’ s in in s t r u c t i o n s d o n o t state the DFT that w ill result from the WFT, it can be calculated calculated . (See (See a p p e n d i x O f o r fo fo r m u l a s a n d examples.)
M e a s u r i n g t h e W F T o n q u i c k d r y i n g m a t e r i a l s, s, such as inorga nic zincs, m ay yield less than a c c ur ur a t e r e a d i n g s .
41. Hardened Painted Painted Surfaces.— Surfaces.— O n c e a c o a t in in g s y s t e m h a s d r i e d o r h a r d e n e d , b u t be b e f o r e t h e r e c o a t w i n d o w h a s e x p i r e d , Reclam Reclam ation specifications specifications imp ose tw o criteria criteria
42
for accept accept ance. The first first is to to me et the m i n i m u m a n d m a x im im u m D F T , a n d t h e s e co co n d i s to to d e t e c t a n d r e p a i r a n y p i n h o l e s in in t h e c o a t in in g o r d a m a g e d a r e a s .
(a) Dry Film Film Thickness.— Thickness.— The DFT of a coating c a n b e m e a s u r e d w h e n t h e m a t e r ia i a l d r i es es o r h a r d e n s b u t b e f or or e t h e r e co co a t w i n d o w h a s expired . The thickness is is comm only specified specified i n m i ls ls , a l t h o u g h s o m e m a n u f a ct ct u r e r ’ s instru ction sheets w ill also use micromet ers (or m icron icron s) in the m etric system . The follow follow ing p ro v id e s co nv e rs io n s o f t he se u n i t s: 1 mil = 0.001 0.001 inch = 25.4 microm eters 1 microm eter = 0.00000 0.000001 1 m eter = 0.039 0.039 m il R e cl cl a m a t i o n s p e c i fi fi e s t h a t t h e h a r d e n e d c o a t e d s u r fa f a ce ce s h a l l m e e t a m i n im im u m a n d m a x im im u m specified specified thickness. DFT is is measured for qu ality ality control and specificatio specification n D FT a c ce ce p t a n c e c r it it e r i a . T h e r e a r e n u m e r o u s t y p e s o f D F T g a u g e s a v a il il a b le le o n t h e c o m m e r c ia ia l m a r k e t . Th e s e ga ga u g e s m e a s u r e th th e t h i c kn kn e s s o f a n o n c o n d u c t iv iv e c o a t in in g o n a m a g n e t i c c o n d u c ti ti v e (f (f e r r ou ou s ) o r n o n m a g n e t i c c o n d u c t iv iv e ( a lu lu m i n u m , br br a s s , b r o n z e , c o p p e r , etc.) etc.) substra te. There are DFT gau ges available t h a t w i ll ll re re a d o n l y m a g n e t i c o r n o n m a g n e t i c s u b s t r a t e s a n d g a u g e s t h a t w i ll ll m e a s u r e b o t h . T h e in in s p e ct ct o r s h o u l d e n s u r e t h a t t h e c o r r e ct ct s u b s t r a t e g a u g e i s b e i n g u s e d a n d t h a t th th e g a u g e r a n g e i s w i t h i n t h e f il il m t h i c k n e s s t o b e measured.
SSP C-P A2 .— Reclam Reclam ation specifies specifies that the D F T i s t o b e m e a s u r e d i n a c co co r d a n c e w i t h S SP SP C - P A 2, 2, “ M e a s u r e m e n t o f D r y C o a t in in g T h i c kn kn e s s w i t h M a g n e t i c G a g e s ,” ,” w i t h t h e exception of the follow follow ing: •
ecified Sect io ion 5 .2 .2.1 .— .— The sp ecified m i n i m u m p e r c e n t a g e t h i ck ck n e s s is is changed from 80 to 90 p ercent.
•
ecified Sect io ion 5 .2 .2.2 .— .— The sp ecified m a x i m u m p e r c en en t a g e t h i ck ck n e s s is is chan ged from 120 120 to 150 percent.
DFT gauges.— T h e t y p e s o f D F T g a u g e s a r e d e t e r m i n e d b y t h e s p e c i fi fi c m a g n e t i c p ro ro p e r t i es es
Field Inspection and Testing of the instrum ent being used in m easuring the c o a t in in g t h i c k n e s s , r a t h e r t h a n b y t h e r e a d o u t m o d e (a (a n a l o g o r d i g i t a l ). ). T h e st st a n d a r d d o e s not cover DFT gauges using an edd y current method.
( Se Se e a p p e n d i x P fo fo r c a li li b r a t io io n a n d p r o c e d u r e f o r e ac ac h g a u g e t y p e a n d a D F T p r o c e d u r e example.). 1.
The followi followi ng sections describe DFT gauges within the standard. •
.—In gen eral, pu lloff lloff Pulloff gauges .—In g a u g e s u s e a p e r m a n e n t m a g n e t in in contact with the coated surface and a calibrated calibrated scale to m easu re the force r e q u i r e d t o p u l l t h e m a g n e t f ro ro m t h e coated su rface. The scale scale is is n onlinear. T h e f o ll ll ow ow i n g a r e t w o t y p e s o f p u l lo lo ff ff g a u g e s a n d t h ei e i r a p p r o xi xi m a t e thickness range: " "
•
Banana gau ge (0 to 200 200 mils). mils). Pencil gau ge (0 to 30 mils). mils).
Constant pressure probe gauges .— T h e g e n e r a l w o r k i n g p r i n c i pl pl e o f t he he c o n s t an an t p r e s s u r e p r o b e g a u g e i s t ha ha t a p r o be ex e rt s a co n st a n t p r e ss u r e o n th e coated s urface, and electronic circuitry circuitry convert s a reference signa signa l into into a c o a t in in g t h i c k n e s s t h a t i s d i s p l a y e d o n a n a n a l o g o r d i g i t a l sc sc r e e n .
Terminology and d efinition.— efinition.— Th e p r o c e d u r e f o r d e t e r m i n in g t h e D F T i n v o l v e s t a k in in g a n u m b e r o f ga ga u g e r e a d i n g s a t r a n d o m locations. locations. These readings are called called spot mea suremen ts. It is imp ortant to understan d gauge reading and spot measurement terminology because without comprehending the m eaning o f the term s, the SSPC-PA2 SSPC-PA2 DFT p r o ce d u r e co u ld b e co n d u ct e d in co r r e ct ly . D e f in in i t io io n s o f “ g a u g e r e a d i n g ” a n d “ s p o t m e a s u r e m e n t ” a r e p r e s e nt nt e d b e l o w : •
T ak ak e 5 sp s p o t m e a su su r e m e n t s (a (a t l e as as t 3 gau ge readings per spot m e a s u r e m e n t ) s p a ce ce d r a n d o m l y w ithin each 100-squ 100-squ are-foot area for DFT measurem ents. The num ber of 100100- squa re-foot areas whe re the spot m e a s u r e m e n t s a r e t o be be t a k e n i s b a s e d o n t h e t o t a l c oa oa t e d s u r f a c e ar ar e a . T h e 100-s 100-squ qu are-foot areas are ran d om ly s e le le c t e d w i t h in in t h e t o t a l co co a t e d a r e a . Table 8.1 8.1 prov ide s the criteria for d e t e r m i n i n g th th e n u m b e r o f 1 00 00 squ are- foot foot area s for for spot m e a s u r e m e n t s co co r r e s p o n d i n g t o t o t a l coated surface area. S u r f ac ac e a r e a s o f i r r e g u l a r l y o r o d d l y s h a p e d s t r u c t u r e s , su su c h a s t r a s h r a c k s , c h a n n e l s , a nd nd I - be be a m s , m a y e x c e e d 1,000 1,000 square square feet because th ese st r u c t u r a l m e m b e r s a r e m a n y si d e d . T h e i n sp sp e c t o r s h ou ou l d r o u g h l y c a l cu cu l a t e t h e a r e a t o d e t e r m i n e d t h e t o t a l co co a t e d surface area.
2.
C al a l ib i b ra r a te t e t h e DF D F T in in st s t ru r u m e n t fo f o r th th e a n t i c ip ip a t e d D F T r a n g e .
3.
M ea e a ssu u r e t h e h a r d en e n e d c oa oa te t e d s u rf r f a ce ce w i t h t h e c a li li b r a t e d D F T in in s t r u m e n t a t t h e n u m b e r o f sp sp o t m e a su su r e m e n t s ind icated in table 1. Di sregard i n c o n s is is t e n t h i g h o r l o w r e a d i n g s t h a t c a n n o t b e r e p e a t e d . T h e f o l lo lo w i n g are the num ber of gauge readings, s p o t m e a s u r e m e n t s , a n d a v e r a g i ng ng p e r 100-- square -foot area: 100 a.
D e te te rm r m i n e t h e 5 s po p o t m e a su su r em em e n t locations required per 100-squarefoot area.
b .
T a k e 3 g a u g e r e a d in g s p e r s p o t measurement and average the 3 readings. This is is a total of 1 5 g a u g e r ea ea d i n g s , m i n i m u m (3 gau ge read ings x 5 spot m e a s u r e m e n t l o ca ca t io io n s p e r 1 0 00square-foot area).
Ga ug uge re read in ing. — A s i n g l e r e a d i n g a t one point.
•
Spo t m ea easu re rem en en t. — T h e a v e r a g e o f a t least three gauge read ings taken at d ifferent ifferent p oints w ithin a 1.51.5-inchinchd i a m e t e r c ir ir c u l a r a r e a .
follow ing is an Outline procedure.— The follow a b b r e v i a t e d o u t l in in e o f S SP SP C - P A 2 p r o c e d u r e .
43
Guide to Protective Protective Coatings: Coatings: Inspection and Maintenance Table 1.—Number of spot measurements based on total coated surface area Total co coated su surface ar area
Number of of 10 100-square-foot ar areas fo for sp spot me measurements
Less Less tha than n 300 300 squa square re feet feet
Each Each 100 100-s -squ quar aree-ffoot oot are area a wit withi hin n the the tot total al are area. a.
Greater than 300 square feet but less than 1,000 square feet
Three (3) 100-square-foot areas within the total area
Equal to and greater than 1,000 square feet
Three (3) 100-square-foot areas for the first 1,000 square feet within the total area; plus One (1) 100-square-foot area for each additional 1,000 square feet of coated areas or fraction thereof
c.
A v e ra ra g gee t he h e 5 in i n d i vi vi du d u a l s po po t m e a s u r e m e n t s t o ob ob t a i n a s i n g l e a v e r a g e d v a l u e f o r t h e 1 0 00- sq sq u a r e foot area.
4.
R e p ea e a t s te t e p s 2 t h r ou o u g h 5 fo fo r t h e rem aining 100-square 100-square -foot -foot areas.
5.
D et e t er er m in i n e m i n im im u m a n d m a xi xi m u m thickness acceptance criteria. criteria.
6.
M i ni ni m u m a c ce ce p ta t a nc n c e. e. a.
A n y n u m b e r o f i n d i vi v i d ua u a l ga g a u ge ge readings m ay be less than 90 percent of the sp ecified ecified thickness.
b .
N o s in g l e a v e r a g e d s p o t m e a s u r e m e n t i n 1 0 00- s qu qu a r e - f o o t area m ay be less than 90 percent of the sp ecifi ecified ed thickness.. Where average spot measurements are less than 90 percent of the specified thickness, additional m e a s u r e m e n t s m a y b e t a ke ke n t o redefine the nonconforming area
7.
44
M a xi x im u m a c ce ce p ta t a nc n c e. e. a.
A n y nu n u m b e r o f i n d i vi v i d u a l ga g a u ge ge r e a d i n g s m a y e x c e e d 1 5 0 p e rc rc e n t of the specified specified thickness.
b .
N o s in g l e a v e r a g e d s p o t m e a s u r e m e n t i n a 1 00 00 -s -s q u a r e - f o o t
area sh all exceed 150 perce nt of the specified specified th ickn ickn ess. Where average spot measurements exceed 150 percent of the specified thickness, additional m e a s u r e m e n t s m a y b e t a ke ke n t o redefine the nonconforming area.
(b) Discontinuity Discontinuity (Holiday) Testing.— Reclam Reclam ation sp ecifies ecifies that coatings su bject to b u r i a l o r im m e r sio si o n s e rv ic e e xp o s u r e s b e tested for ho lid lid ays (i.e (i.e., ., p inholes and void s). s). H o l id id a y s p r o v i d e a n a v e n u e f or or m o i s t u r e t o p e n e t r a t e t h r o u g h t h e c o a t in g t o t h e s u b s t r a t e , leading to ge nera l corrosion, pitting, and u n d e r f il il m c o r r o si si o n . T h e r e a r e t w o t y p e s o f h o l id id a y t e s t i n g : lo w voltage and high voltage. The applied voltage i s b as as e d o n t h e c o a t i n g t h i c k n e ss ss a n d t h e coating dielectric strength. Low-voltage testers are u sed on thin films (20 (20 mils and less), less), a n d h i g h - v o lt lt a g e t e s te te r s a r e u s e d o n h i g h b u i ld ld films films (20 m ils ils or grea ter) or as de term ined by t h e m a n u f a ct ct u r e r t o p r e v e n t c o a ti ti n g d a m a g e . Using voltages that are too high or leaving the i n st st r u m e n t in o n e p l a ce ce t o o lo lo n g m a y d a m a g e t h e c oa oa t i n g b y sp sp a r k i n g o r b u r n i n g t h r o u g h t h e coating. Thin coatings are m ore su su sceptible to v o l t a g e d a m a g e . T e s t in in g o f co co a t i n g s t h a t contain electricall electrically y con con d uctive pigm ents such a s a l u m i n u m f la la k e s , g r a p h i t e , o r z i n c is is n o t r e c o m m e n d e d b e c a u s e a n e l e c t r ic ic d i s ch ch a r g e m a y s p a r k t h o u g h t h e cco o a t i n g a t c o n d u c t iv iv e p a r ti cl e s, d a m a g in g th e c o a ti n g or in d ic at in g d iscontinuities w here non e exist. Suggested
Field Inspection and Testing v o l t a g e s a t D F T ra ra n g e s a r e p r o v i d e d i n t a b l e 1 of the N AC E RP RP 0188. 0188. Reclam Reclam ation sp ecifies ecifies that testing be in accordan ce with N ACE RP 0188, 0188, except that: •
T e sstt in in g is is n ot o t r eq eq u i re r e d o n c on on d u c t i v e c o at a t in in g s p i g m e n t e d w i th th a lu lu m i n u m , grap hite, zinc, or other electrical electrically ly conductive pigments.
•
U si s i n g a d e t er e r g en en t w et e t ti t i n g so s o lu l u ti t i o n is is n o t p e r m i t te te d ( d e t e r g e n t s m a y c o v e r over p inholes after testing, leaving the f a ls ls e i m p r e s s i o n t h a t n o p i n h o l e s exist).
Previou s versions of Reclam Reclam ation coatin coatin g specifications specifications reference ASTM D 5162 for for holiday testing. ASTM D 516 5162 2 and and N ACE RP RP 0188 are essentially equivalent, but the N AC E v e r s io io n i s m o r e c o m p l e te te a n d e a si si e r t o f o ll ll o w . ( Se Se e a p p e n d i x Q f o r th th i s p r o c e d u r e .) .)
ly f o r Me tho d B .— T h i s m e t h o d i s p r i m a r i ly l a b o r a t o r y u s e , a l th th o u g h i t i s o f te te n e m p l o y e d in th e field. field. The met hod is not suitable for c o a ti ti n g s w i t h a t h i c k n e ss ss g r e a t e r t h a n 5 m i l s . A lattice pattern of 6 to 11 evenly spaced horizon tal and ver tical lines are cut into the coatin coatin g to the su bstrate. Pressur e-sen e-sen sitive sitive t a p e i s a p p l ie ie d o v e r t h e l a t t ic ic e p a t t e r n a n d p u ll e d o f f. C o a ti n g a d h e s io n is a ss es se d b y m a k i n g t h e b e s t m a t c h t o a c o m p a r i s o n s c a le le o f 0B (low (low est) to 5B (highest) of narrat ive and p h o t og r a p h i c d e sc r ip t i o n s p r o v i d e d i n t h e standard.
(b) Adhesion, Pulloff Pulloff Method (ASTM (ASTM D 45 41 ).— T h i s m e t h o d i s m o r e q u a n t i t a ti ti v e b u t requires an experienced op erator for reproducibility. These testers are r e c o m m e n d e d f o r f la la t h o r i z o n t a l s u r f a ce ce s u n l e s s o t h e r w i s e s t a te te d i n t h e ap ap p e n d i x . T h e s t a n d a r d l is is t s t h e f o ll ll o w i n g t h r e e t y p e s o f t e st st e r s i n t h e a n n e x : estricted Type I, fixed.— Type I testers are r estricted
42. Destructive Destructive Test Methods.— D e s t r u c t i v e t e s t m e t h o d s a r e n o r m a l ly ly u s e d t o e v a l u a t e o v e r c o a ti ti n g o r a i d i n d e t e r m i n i n g a c o a t in in g failure. The following sections are abbr eviated d e s c r i p t io io n s o f t h e d e s t r u c t iv iv e t e s t in in g m e t h o d s listed in the above Ph ysical Coating Insp ection Su r v e y m e t h o d . (a) Adhesion, Tape Method (ASTM D 3359).— T h i s t es es t i s c on on s id id e r e d s u b je je ct ct i v e a n d s h o u l d be b e p e r f o r m e d b y q u a l if ied ie d a n d e x p e r i e n c ed p e r s o n n e l . T h e c h o i s e o f te s t m e t h o d d e p e n d s on coating thickness.
Metho M etho d A .— T h i s m e t h o d i s u s e d o n coatings 5 m ils thick or greater. An “X” cut is is m a d e i n t h e c o a t in in g t o t h e s u b s t r a t e . P r e s s u r e s e n s it it i v e t a p e i s a p p l ie ie d o v e r t h e “ X” X” c u t a n d p u ll e d o f f. C o a ti n g a d h e s io n is a ss es se d b y a comp arison scale of 0A (low (low est) to 5A (highest), as described b y w ritten d efinitions efinitions p r o v i d e d in t h e s ta n d a r d .
t o l a b or or a t o r y u s e .
Type II, fixed alignment.— alignment.— Type II testers w e r e d e v e lo lo p e d fo r l a b o r a to to r y u s e b u t a r e e m p l o y ed ed i n t h e f ie ie l d . T y p e I I a r e t h e m o s t c o m m o n p u l l o ff ff a d h e si si o n t e s t e r s fo fo r f ie ie l d u s e . ( Se Se e a p p e n d i x R f o r t h i s p r o c e d u r e .) .)
Type III, self-aligning self-aligning o r hydraulic.— T y p e I II II t e s t er er s w e r e d e v e l o p e d f o r l a bo bo r a t o r y u s e bu t ar e em p lo ye d in th e fi eld el d . (Se e a p p en d ix S f o r p r o c e d u r e .) .)
Dry film thickness by Tooke gauge (ASTM D 41 38 ).— T h e T o o k e g a u g e i s u s e d f o r m e a s u r i n g t h e n u m b e r o f c o a t s a p p l ie ie d a n d DFT if the coat ing laye rs can be ide ntified ntified b y color differenc differenc e or by a distinctive line. line. (See (See a p p e n d i x T f o r th th i s p r o c e d u r e . )
45
Chapter X Maintenance Coatings Reclamation infrastru ctures m ay still still be coated coated w i t h t h e o r i g i n a l m a t e r i a l s fr fr o m t h e i n i t ia ia l i n s t a ll ll at at i o n o r t h e y m a y h a v e r e c e i v ed ed f u l l, l, p a r t i a l , o r sp ot c o a t i n g r e p a i r in t h e i n t e r v e n i n g y e a r s . O b v i o u s l y , an an y c o a t i n g m ater ial has a finite service life, life, and m a i n t e n a n c e co co a t i n g s h a v e b e c o m e a n imp ortant compon ent in maintaining the stru ctural integrity of high-capital-cost infrastructures. lified ed d efinition efinition of 43. Definition.— A simp lifi m a i n t e n a n c e c o a t in in g s i s “ t h e r e c o a t i n g o f a n y e x is is t in in g c o a t e d s u b s t r a t e s u r f a ce ce t o p r e v e n t c o r r o si si o n o r t o m a i n t a in in a p p e a r a n c e .” .”
m a y a l so so b e a m a jo jo r c o n s id id e r a t i o n , a n d t h e s e associated costs m ay be d iffi ifficult cult to assess. assess. To p r o v i d e a b a s is fo r r i sk e v a l u a t i o n , i n s p e ct io n o f th th e c o a t i n g a n d s u b s t r a t e is is r e c o mm mm e n d e d . ct i v e 46. Inspection.— T o d e t e r m i n e t h e c o r r e ct action required, structures identified for m a i n t e n a n c e co co a t i n g s w o r k s h o u l d b e i n s p e c t e d b e f or or e b e g in in n i n g w o r k . P r e l im im i n a r y w o r k s h o u l d i n c lu lu d e g a th th e r in i n g b a ck ck g r o u n d i n fo fo r m a t io io n o n t h e s t r u c tu tu r e , i n c lu lu d i n g location, location, original installation d ate, dim ensions, d r a w i n g s, s, s u b s t r a te te t y p e , a n d c o a t i n g h i st st o r y . T h e c o a ti ti n g h i s t o r y s h o u l d i n c l u d e t h e f o ll ll o w i n g i n f o r m a t i o n , if if k n o w n :
44. Purpose.— The basic p u rp oses of of a
•
S e rv r v ic ic e e xp xp os o s ur ur e
c o a t in in g p r o g r a m t o m a i n t a i n R e c la la m a t i o n structures are to:
•
T y p e o f s u b st st r a t e
•
P re r e v en e n t si s ig n if i f i c a n t lo lo ss s s of of m e t a l
•
S u r fa fa c e (a (a n c h or or ) p r of of i l e
•
P re re v vee n t si s ig ni n i fi fi c an a n t de de g grr a d a ti t io n o f c o a t in in g m a t e r i a l
•
A g e o f c o at at i n g
•
T yp y p e o f ex e x i s ttiin g co c o aatt in in g m a t e ri ria l o r b r a n d n a m e
•
D FT
•
I d e n ti t i fi fi c a ti ti o n a n d c o nc n ce n ntt ra r a ti t i on on o f toxic m etals in the existing coating ( ca ca d m i u m , c h r o m i u m , le le a d , e t c .) .)
•
• •
M ai a i n t a in in ae a e sstt h e t ic ic s o r t h e a p p e a ra ra n ce ce o f s tr tr u c t u r e s e x p o s e d t o p u b l ic ic v i e w I d e nt n t if i fy by b y co c o lo lo r c od od e M i ni ni m iz iz e fu t u re re re r e p ai a i r c os os ts ts
45. Risk Evaluation.— Risk Risk ev aluation is p ri m ar i ly a p ro jec t of fic e re sp on si bi l ity . Th e o v e r r i d i n g o r u l ti ti m a t e c o n s i d e r a t i o n i n evalu ating risks associated associated w ith coating coating s is is w h e t h e r t h e c o a t i n g i s m a i n t a in in i n g s t r u c t u r a l integrity or if coating coating d egrad ation is allowin g corrosion to p roceed , leading to th e possibility possibility of structu ral failure. failure. There is no stand ard m e t h o d t o e v a l u a t e r i s k s ; h o w e v e r , t he he m o s t b a s ic a p p r o a ch i s t o co m p a r e e st im a t e d p a r t ia l o r t o t a l m e t a l w o r k r e p l a ce ce m e n t c o s t s w i t h t h e e s ti ti m a t e d c os os t s o f a m a i n t e n a n c e c o a t in in g p r o g r a m . Sa fe t y t o th e p u b li c a n d w o r k e r s
(a) Inspection Schedule.— Ideally, inspection surveys should be cond ucted every 3 to 5 y e a r s , d e p e n d i n g o n t h e s e r v i ce ce e x p o s u r e a n d t h e s t r u c t u r e t y p e . T h e 3 - t o 5 -y -y e a r interva l is is reasonable for stru stru ctures situated in a t m o s p h e r i c s e r v i ce ce e x p o s u r e . F o r s t ru ru c t u r e s r e q u i r i n g d e w a t e r i n g , a 5- y e a r i n s p e c t io io n interval may not be achievable; how ever, some d e s i g n a t e d i n t e r v a l s h o u l d b e i n i t ia ia t e d . ction (b) Inspection Types.— The typ e of inspe ction s u r v e y d e p e n d s m a i n l y o n t h e t i m e a l l ot ot t e d and accessibility. accessibility. Exterior Exterior su su rfaces rfaces in in
47
Guide to Protective Protective Coatings: Coatings: Inspection and Maintenance a t m o s p h e r i c e x p o s u r e s a r e r e a d i ly ly a c c es es s ib ib l e for inspection. Interior insp insp ections of p e n s t o c k s , p i p i n g , s cr o l l c a s es , a n d o t h e r w a t e r - b e a r in in g s u r f a ce ce s r e q u i r e a p l a n n e d o u t a g e t o d e w a t e r . I n t e r io io r in in s p e c t i o n s a r e c o n s i d e r e d c o n f in in e d s p a c e , a n d a p p r o p r i a t e safety requiremen ts must be met.
eleme nts (beam s, connec tions, tions, edg es, etc.) etc.) of the stru cture or facility facility are insp ected separately. 1.
O b se se r ve v e a n d d o c u m en e n t t h e fo fo ll ll o w i n g coating cond cond itions: itions: •
D e fe f e ct c t s : b li l i s te te r in in g , c h a l k in in g , cracking, erosion, delamination, p in h o le s , p e e lin g , u n d e r c u t t in g , o r o t h e r d e f e ct ct s
•
A p p e a ra r a n ce c e : c oa o a t in in g o r t op o p c oa oa t loss, loss, abrasion streaks, ru st stainin stainin g, fading color, weathering, or other a b n o r m a l a p p e a ra ra n c e
T h e r e a r e fo fo u r t y p e s o f i n s p e c t io io n : t h r e e t y p e s a r e c o at at i n g r e l a te te d a n d o n e i s st st r u c t u r a l . T h e four types are: • • • •
G e n er e r a l o v er er vi vi ew ew s ur u r ve ve y D e ta ta il i l e d v is i s u a l s u rv rve y P h ys y s iicca l co co aatt in i n g in i n sp s p e ct c t i on o n s u rv r v eey y S t r u ct c t u r a l s u r ve ve y
F o r m o s t R e c la la m a t i o n s t r u c t u r e s , t h e g e n e r a l o v e r vi v i e w a n d d e t a i le le d v i s u a l s u rv rv e y m e t h o d s are sufficient sufficient to ide ntify coating coating an d c orrosion d e t e r i o r a t i on on t r e n d s .
2. By obser obser vation, docum ent the follow follow ing r u s t c o n d i t io io n s : •
T yp y p ee:: u n if i f o rm r m r u st s t ed e d s u r fa f a ce ce o r p it t in g
General overview survey.— This qualitative s u r v e y c a n b e a c co co m p l i s h e d i n a fe fe w h o u r s a n d i s a d e q u a t e t o a s c er er t a i n s e v e r e c o r r o s io io n c o n d i t i o n s a n d d e g r a d e d c o a t in in g s . O n l y t h e m ajor ajor features o f the stru cture or facility facility are inspected. 1.
•
3.
T h e ge g e n e ra r a l c o n d it i t io io n o f c o a ti t in g ; check for defects or deterior ation A n y ev ev id id e nc n c e of o f r u st st i n g
D et e t er e r m i n e th t h e t yp y p e o f t o xi x i c m e t a ll b a se d p a in t a n d it s co n ce n tr a ti o n , i f p r e se n t . R a te t e t he he c o n d it it io io n o f t he h e co c o a ti t in g o n e a c h m a jo jo r s t r u c t u r a l f e a t u r e a s g o o d , fair, or po or.
Detailed visual survey.— T h e t i m e r e q u i r e d t o c o n d u c t t h i s s u r v e y v a r i e s fr fr o m a f e w h o u r s to about 1 day, dep end ing on the size of the s t r u c t u r e . T hi hi s s e m i q u a n t i t a t iv iv e s u r v e y r e q u i r e s a m o r e d e t a i le le d d e s cr cr i p t i o n a n d d o c u m e n t a t i o n o f th th e c o a t in in g c o n d i t io io n a n d c o r r os os i on on . M a jo jo r f ea ea t u r e s an an d s t r u c t u r a l
48
O n f l a t o r c u r v e d s u r f a ce ce s " At corners or edges is t e r s " U n d e r b l is •
E st st im im a t e t h e a m ou o u n t o f r u st s t by by using SSPC-VIS SSPC-VIS 2. 2. (See app end ix U f o r p r o c e d u r e s .) .)
•
M e t al a l lo lo ss s s : m i ni n i m a l o r s ig i g ni n i fi fi ca ca n t .
V is is u al a l ly ly o bs b s eerr v e: e: •
2.
"
3 . D e t er er m i n e t h e t y p e o f t o xi xi c m e t a ll b a se d p a in t a n d it s con co n ce n tr a ti o n , i f p re se n t . 4 . R a te te e a ch ch s t ru r u c t u r al al c om o m p o n een nt s e p a r a t e l y a s g o o d , fa i r , o r p o o r a n d comb ine the results. Using SSPC-VIS SSPC-VIS 2 t o e s ti ti m a t e t h e a m o u n t o f ru ru s t is is p r e f e r r e d m e t h o d . A w e i g h t i n g s y s t e m o r s p r e a d s h e e t c a n h e l p f a ci li li t a t e b y c o m b i n i n g i n d i v i d u a l r a t in in g s i n t o a n overa ll assessmen t, setting setting p riorities, a n d d e v e l o p i n g q u a n t i t ie ie s fo fo r a p r e l im i n a r y c o s t e s ti m a t e .
Physical coating inspection survey.— Th e t i m e r e q u i r e d t o c o n d u c t t h i s s u r v e y i s f ro ro m 1 d a y t o s ev ev e r a l d a y s , d e p e n d i n g o n s t r u c t u r e size and access to th th e coated coated surface. The
Maintenance Coatings s u r v e y i n c o r p o r a t e s t h e o b s e r v a t i o n s r e c o r de de d i n t h e D e t a i l ed ed V is is u a l S u r v e y w i th th q u a n t it it a t iv iv e m e a s u r e m e n t s . Th i s s u r v e y e v a l u a t e s w h e t h e r a n e x i s t in in g c o a t i n g c a n b e s p o t r e p a i r e d o r o v e r c o a te te d o r i f fu fu l l r e m o v a l a n d r e co co a t i n g i s requ ired. For a higher level of confidence , the s u r v e y s h o u l d b e c o n d u c t e d b y a c e r t if if ie ie d N A C E o r S SPC SP C c o a t in g s p e c ia l is t . 1 . O b se s e r v e a n d d o c u m e n t t h e f o ll ll ow ow i n g coating cond cond itions: itions: •
•
D e fe fe c t s: s: b li li s te te r in in g , c h a l k in in g , cracking, erosion, delamination, p in h o le s , p e e lin g , u n d e r c u t t in g , o r o t h e r d e f e ct ct s A p p e a ra r a n ce c e : c o at a t in in g o r t op o p c oa oa t loss, abr asion streak s, rust staining, fading color, weathering, or other abnormal appearance.
2 . O b se s e r v e a n d d o c u m e n t t h e fo fo l lo lo w i n g r u s t c o n d i t io io n s : •
T yp y p ee:: u n i fo fo rm r m r u st s t ed e d s u r fa fa ce ce o r p it t in g
•
D et e t e rm rm i ne n e th th e ty ty p e an an d concentrati on of toxic m etal-based p a in t , if i f p r e se n t
•
D et e t er er m i n e t h e d e p t h a n d f re re q u en en c y of corrosion corrosion p its
•
U s e a k n if i fe t o d e te t e rm r m i n e th t h e le le n ng g th th o f u n d e r c u t t in in g c o r r o s i o n
•
U se s e a T o ok o k e g aau u g e to to d e te te rm rm i n e t h e n u m b e r o f c o a t in in g s
•
M e as a s u re r e t h e st s t ee ee l w al a l l t h ic ick n es es s w i t h a n u l t r a so so n i c t h i ck ck n e s s g a u g e
•
A p p l y te te sstt p a tc tc h e s to to d e te ter m i n e if the coating is comp atible for for overcoatin g (ASTM D 5064) 5064)
Struc Str uc tura l inspe i nspe ctio n .— T h e s t r u c t u r a l i n s p e c t io io n c a n b e c o n d u c t e d i n c o n ju ju n c t i o n w ith any of the above surveys. Structural m e m b e r s a n d c o m p o n e n t s a r e i n sp sp e c t e d f o r severe m etal loss, loss, broken joints, defective defective w elds, bent m embers, or other structural d efects. efects. N orm ally, inspections are by visual observation.
"
O n f l at at o r c u r v e d s u r f a ce ce s " At corners or edges is t e r s " U n d e r b l is •
R u s t r a t in i n g b y S SP SP C -V - V IS IS 2 . ( Se Se e app endix U for procedure.)
•
M e t a l l o s s: s: m i n im i m a l o r si s ig n i fi fi c an an t
3 . P e r fo fo r m t h e fo fo l lo lo w i n g q u a n t it it a t iv iv e measurements: •
T es e s t a d he h e s io i o n b y on o n e or o r b ot o t h of o f th th e f o ll ll o w i n g m e t h o d s : "
Pu lloff lloff (ASTM D 454 4541) 1) Tape (A STM ST M D3359) D335 9) " •
D et e t er er m i n e D FT F T (S (S S P C - PA P A 2) 2)
•
D et e t er e r m i n e t h e p re r e se se n ce ce aan nd concentra tion of solub le salts, salts, if p r e se n t
47. Toxic-Based Paints.— D u r i n g t h e inspection, samp les of of the existing existing coating m a t e r ia ia l sh sh o u l d b e a n a l y z e d t o d e t e r m i n e t h e typ e and concentra tion of toxic metals. The comm on toxic m etals in in p re-1990s re-1990s paint ar e c a d m i u m , c h r o m i u m , c o b a lt lt , a n d l e a d ; h o w e v e r , a r se se n i c , ba ba r i u m , be be r y l l iu iu m , m e r c u r y , s il il v e r , s e le le n i u m , v a n a d i u m , o r o t h e r h e a v y m e t a l s m a y b e p r e s en en t i n v e r y l ow ow l ev ev e l s . T h e m o s t co co m m o n h e a v y m e t a l i n p a i n t u s e d on Reclam Reclam ation projects projects is red lead prim er. It w a s a n e x c e ll ll e n t c o r r o s io io n i n h i b i ti ti n g p r i m e r o n m etal surfaces. The use of red lead primer has d r a m a t i ca ca l ly ly d e c li li n e d i n t h e c o a t i n g i n d u s t r y since the late 1980s, 1980s, and Reclamation no lo nge r s p e c if if ie ie s r e d l e a d p r i m e r . T h e r e i s n o p r o b l e m w i t h r e d l e a d p r i m e r a s l o n g a s it it r e m a i n s intact on the structure. T h e p r o b l e m w i th th l e a d - b a s e d p a i n t s is is contam ination of th e local env ironm ent (soil (soil a n d w a t e r ) a n d e x p o s u r e t o h u m a n s . L ea ea d
49
Guide to Protective Protective Coatings: Coatings: Inspection and Maintenance e x p o s u r e n o r m a l l y o cc cc u r s d u r i n g t h e s u r fa fa c e p r e p a r a ti o n p r o ce ss , a s old ol d co a t in g s a r e r e m o v e d a n d l e a d p a r t i cl cl e s b e c o m e a i r b o r n e . T h e e n v i r o n m e n t i s co co n t a m i n a t e d b y l e a d p a r t ic le fa llo ll o u t . H u m a n s a r e c o n t a m i n a t ed b y inhaling or ingesting th th e lead lead p articles. articles. The m ost serious adv erse he alth effect effect of lead e x p o s u r e i s p e r m a n e n t d a m a g e t o th th e c e n t r a l nervous system.
b ec a u se th e p a r ti cl e s a r e t oo sm a ll to b e v is ib ly s e e n . L e a d d u s t o n t h e s k in in i s n o t h a z a r d o u s a s lo lo n g a s i t is is n o t i n h a l e d o r i n g e s t e d . P r o p e r respir atory pr ote ction, ction, consisting consisting of either a irf e d r e s p i r a t o r s , p o s it it i v e p r e s s u r e h o o d s , o r n e g a t i v e p r e s s u r e H E P A f i lt lt e r -c -c a r t r i d g e h a l f o r f u l l f a ce ce d r e s p i r a t o r s , s h o u l d b e w o r n . T h e f o ll ll o w i n g p r o v i d e s so so m e c o m m o n s e n s e p r o t e ct io n b u t d o e s n o t in c lu d e a ll n e ce ss a r y requirements:
existing coatin coatin g (a) Testing.— Testing of existing m a t e r ia ia l s sh sh o u l d b e p e r fo fo r m e d b e f o r e s t a r ti ti n g c o n t r a c t o r m a i n t e n a n c e c o a ti ti n g w o r k . T h e p u r p o s e o f t e st in g i s t h r e e fo ld : (1) (1 ) t o m i n i m i z e e x p o s u r e t o e n v i r o n m e n t a n d w o r k e r s ; ( 2) 2) t o r e d u c e s u r f a ce ce p r e p a r a t i o n c o s t s ; a n d ( 3) 3) t o d e t e r m i n e t h e t y p e a n d c o n c e n t r a t io io n o f a n y toxic m etals presen t. The follow follow ing test test m e t h o d s a r e r e c om om m e n d e d :
Scre en te sting.— sti ng.— Screen tests wi ll indicate the p resence of toxic toxic metals bu t w ill ill not ind icate the concentration. These tests are not i n t e n d e d t o e q u a l o r r e p l a c e la la b o r a t o r y a n a l y s is is . T h e f o l lo lo w i n g t w o c o m m o n t o x ic ic m e t a l s ca ca n b e d e t e c t e d b y c o l o r c h a n g e u s i n g p re m i xe d r e a ge n t s: •
•
L e ad ad a t co c o n ce c e n tr tr a t i o ns ns of of 2, 2 ,0 00 00 pa pa r t s p e r m il lio li o n ( p p m ) ( 0 .2 p e r c en t ) o r m o r e . ( Se Se e ap ap p e n d i x V f o r m a n u f ac ac t u r e r ' s i n f or or m a t io io n a n d t h i s p r o c e d u r e .)
•
W e a r w o r k c l o th t h in in g d u r in in g r em em o v a l o p e r a t i o n s a n d h a v e c l o t h in in g i n d u s t r i a l w a s h e d b y c o n t r a ct ct o r o r o w n e r .
•
W e ar a r r es e s pi p i ra r a to t o ry r y p r ot o t ec e c t io io n a p p r o p r i a t e t o c o n c e n t r a t io io n l e v e l a n d exposure time period.
•
W a sh s h h a nd n d s a n d f ac a c e b eeff o re r e e at a t in in g or or smoking.
•
A f te te r w o rk r k , s ho ho w e r an an d c h haa n ge g e in i n to to s t r e e t cl cl o th th i n g t o p r e v e n t c o n t a m i n a t i n g y o u r v e h i c le le , h o m e , a n d family.
F o r co co m p r e h e n s i v e r e q u i r e m e n t s fo fo r p e r s o n a l safety, see the following following Cod e of Fede ral Regu lation lation s (CFR): •
2 9 C F R 1 91 91 0. 0. 10 10 18 18 , A r s e n ic ic
•
2 9 C FR FR 19 19 1 0. 0. 1 0 2 7 , C a d m i u m
•
2 9 C F R 19 192 6. 6. 55 55 , G a s es e s , V ap ap o r s, s, F u m e s , D u s t s , a n d M i s ts ts
•
2 9 C FR F R 19 19 26 26 .6 .6 2, 2, Le Le a d
+6
C hr h r om o m a t e ( a s C r ) at concent concent rations of 3 microgram s or more. (See a p p e n d i x W fo fo r m a n u f a c t u r e a n d p r o c e d u r e . )
hi p s a m p l e s Laboratory testing.— P a i n t c hi s h o u l d b e t a k e n a n d p r o v i d e d t o a n a c c re r e d i te te d laboratory for anal ysis ysis to verify verify concentratio n, even if screen tests w ere not positive . The r e s u l t s s h o u l d b e e v a l u a t e d b y a c e r t i f ie ie d ind u strial hyg ienist. (See (See app end ix X for sam p ling, ling, labora labora tory testing, esti estim m ated costs, a n d w e b s it it e s fo fo r a c c r e d i t e d l a b o r a t o r ie ie s a n d ind ustrial hygien ists by city an an d State).
48. Worker Protection Protection from Toxic-Based in g o p e r a t i o n s a r e t h e m o s t Paints.— Bl a s t in l ik ik e l y e v e n t w h e r e l e a d i s i n ha ha l e d o r i n g e s t e d
50
49. Lead Exposure Levels by Removal Methods.—E n g i n e e r s , m a n a g e r s , a n d w o r k e r s s h o u l d b e a w a r e t h a t s u r f a ce ce p r e p a r a t i o n m e t h o d s w i ll ll g e n e r a t e a i r b o r n e l e a d p a r t i c le le s . T h e O c c u p a t i o n a l S a fe fe t y a n d H e a l t h A d m i n i s t r a t io io n ( O SH SH A ) m o n i t o r e d s e v e r a l t y p e s o f l e a d r e m o v a l o p e r a t i o n s f o r t y p i ca ca l a n d m a x im im u m e x p o s u r e s . T h e m o n i t o r ed ed r e s u l t s in in d i ca ca t e h i g h e x p o s u r e l e v e l s , a n d n o s u r f a ce ce p r e p a r a t i o n m e t h o d w i l l n ot ot t o t a l ly ly e li li m i n a t e a i rb rb o r n e le le a d p a r t i c le le s . V ac ac u u m shro ou u d e d e q u i p m e n t w i ll ll r ed e d u c e th th e a m o u n t
Maintenance Coatings of airborn airborn e particles but w ill ill not elim elim inate t h e m . T a b le le 2 p r o v i d e s O SH SH A r e s u l t s fo fo r t y p i c a l a n d m a x im im u m l e a d e x p o s u r e l e v e ls ls b y removal method.
Table 2.—Typical and maximum lead exposure levels in micrograms per cubic meter by removal method Typical exposure
Maximum exposure
Open blast cleaning
17,300
59,000
Blast cleaning in containment system
25,700
59,000
Welding, cutting, or burning
600
28,000
Removal method
Hand tool cleaning
45
167
Power tool cleaning
735
20,600
Chemical stripping
11
476
500
2,100
Movement (air, foot traffic, cleanup, etc.) in the containment system (causes particles to become airborne)
50. Corrective Action.— A f t e r o n e o f t h e a b o v e i n s p e c t i o n s u r v e y s ( s ee ee c h a p t e r X , subsec tion tion 47(b), “Inspe ction Types”) has bee n c o m p l e t e d a n d e v a l u a t e d , t h e co co a t i n g m a y b e i n s o m e s t a t e o f d e t e r i or or a t i o n , t h u s r e q u i r in in g corrective action. Corr ective ective action action ma y range f r o m n o p a i n ti ti n g t o f u l l r e m o v a l a n d r e c o a ti ti n g . The followin followin g sections sections p rovid e altern ative r e m e d i a l o p t i o n s b a s e d o n t h e i n s p e c t io io n assessment.
(a) No Painting Required.— The inspection assessmen t indicates the follow follow ing: (1) (1) the coating is in in good to excellent excellent cond ition; ition; (2) the serv ice en vironm ent is m ild; (3) (3) littl littlee corrosion is exp ected to p rogress at coating coating film film b reaks; (4) m inor d iscoloration iscoloration is n oted b u t a p p e a r a n c e i s n o t a n im p o r t a n t fa ct o r ; a n d (5) (5) no significant met al loss is is noted . E s se se n t i a ll ll y , t h i s o p t i o n m e a n s “ d o n o t h i n g f o r “ x ” n u m b e r y e a r s .” .” It d o e s n o t m e a n ?d o n o t h i n g f or or e v e r . ” I t m e a n s t h a t t h e co co a t i n g m a i n t e n a n c e p r o g r a m i s d e l a y e d u n t i l so so m e t im im e i n t h e f o r e s ee ee a b l e f u t u r e w h e n c oa oa t i n g
d e t e r io io r a t i o n r e q u i r e s a t t e n t i o n o r u n t i l s o m e t i m e w h e n c o a t in in g m a i n t e n a n c e is is s ch ch e d u l e d w i t h o th th e r m a j o r m a i n t e n a n c e p r o g r a m s . A n o t h e r r e a s o n f or or n o t p a i n t in in g i s th th a t fu fu n d i n g m a y n o t b e a v a i l a b l e fo fo r “ x ” n u m b e r o f y e ar ar s . in o r d e r (b) Spot Repairs.— S p o t r e p a i r s a r e in w h e n t h e i n s p e c t io io n a s s e s s m e n t i n d i ca ca t e s t h e followin followin g: (1) the coating is d eteriorating in localized localized areas; (2) (2) the service en vironm ent is mild to corrosive; (3) corrosion corrosion is exp ected to p r og re ss a t c o a t i ng fil m br e a k s; ( 4) 4) d i s co co l or or a t i o n i s n o t e d b u t a p p e a r a n c e m a y o r m a y n o t b e a n im im p o r t a n t f a ct ct o r ; a n d ( 5) 5) m i n o r m e t a l l o ss ss i s n o t e d . T h i s o p t i o n i s a p p r o p r i a t e f o r i s o la la t e d a n d relatively small areas that do no t exceed 1 p e r c e n t o f t h e t o t a l co co a t e d s u r f a c e a r e a a n d a r e n o t i n a h i g h a p p e a r a n c e a r e a . I f c ol ol o r is is i m p o r t a n t , s u c h a s i n a p u b l ic ic a r e a , t a k e c o lo lo r c h i p s a m p l e s to to t h e c o a t in in g m a n u f a ct ct u r e r t o m atch the existing existing color because the original c o a t in in g c o l o r m a y h a v e f a d e d . Spot repairs are a viable option for a t m o s p h e r i c , bu bu r i a l , a n d i m m e r s io io n s e rv rv i c e exposures.
(c) Spot Repairs Repairs Plus Full Recoat.— S p o t r e p a i r s a r e in in o r d e r w h e n t h e i n s p e c t io io n assessmen t indicates the follow follow ing: (1) (1) the coating is d eteriorating in localized localized areas t hat r e p r e s e n t b e t w e e n 1 a n d 3 p e r c e n t o f t h e t o ta ta l a r e a a n d a r e e x p e c t e d t o d e t e r i o r a t e fu fu r t h e r ; (2) (2) the service environm ent is mild to corrosive, (3) (3) corrosion is expected to p roceed at coating film film break s, (4) (4) discoloration discoloration is n o t e d a n d a p p e a r a n c e i s a fa fa c t o r , a n d ( 5 ) m i n o r t o m o d e r a t e m e t a l l o ss ss i s no no t e d . T h i s o p t i o n i s a p p r o p r i a t e f o r c o a t in in g s t h a t a r e i n r e l a t iv iv e l y g o o d c o n d i t i o n b u t d e f e c t s a n d corrosion are n oticeab oticeab le. Th e coating shou ld still be resilient, it can still hav e a red u ced D F T, T, a n d a d h e s io io n s h o u l d b e g o o d w h e r e t h e c o a t in in g h a s n o t d e t e r io io r a t e d . W h e n overcoating an existing existing p aint, a test pat ch s h o u l d b e a p p l i e d t o d e t e r m i n e c om om p a t i b i li li t y be t w ee n th e c o at i ng m a te r ia l s. Th e te st p a t ch e s s h o u l d b e e v a l u a t e d b e t w e e n 1 a n d 3 mon ths after app lication. lication. The stru cture’s
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Guide to Protective Protective Coatings: Coatings: Inspection and Maintenance a p p e a r a n c e m a y b e o f a e s th th e t i c i m p o r t a n c e ( s u c h a s w h e n i n p u b l i c v i ew ew ) , a n d a f u l l r e co co a t w i ll ll p r o v i d e a u n i f or or m c o l or or a n d g l o ss ss . The spot rep air plus full recoat is is a viable o p t i o n f o r c oa oa t i n g s t r u c t u r e s i n a t m o s p h e r i c s e r v i ce ce e x p o s u r e s , b u t i t i s n o t r e c o m m e n d e d f o r b u r i a l a n d i m m e r s io io n s e r v i c e e xp xp o s u r e s .
• • • • •
C o lo lo r a n d g lo lo ss ss r et et e n ti ti o n . R e co a t w in in d o w C u re r e o r d ry r y ti ti m e F le xi xi b il it y M il i l d e w or o r fu f u n g u s r es e s iiss t a n ce ce
(b) Suitability Suitability to Substrate Substrate Type.— •
F er e r ro r o us u s (s (s ttee el el or o r ir i r on on )
•
N o n fe f e rr r r ou o u s (a lu l u m i nu n u m , b ra r a ssss , b ro r o n z e, e, o r c op op p e r )
•
C on o n cr c r et et e o r m as a s on on ry ry
•
O ld l d c oa o a t in in g s
•
W ood
(d) Complete Removal and and Recoat.— C o m p l e t e ly ly r e m o v i n g t h e o ld ld c o a t i n g a n d r e c o a t in in g i s i n o r d e r w h e n t h e i n s p e c t io io n assessmen t indicates the follow follow ing: (1) (1) the c o a t in in g i s d e t e r io io r a t i n g i n lo c a li li z e d a n d l a r g e areas representing greater than 3 percent of the t o t a l a r e a , a nd nd i t i s e x p e c t e d t o d e t e r i or or a t e furth er; (2) (2) the service environm ent is mild to corrosive; (3) (3) corrosion corrosion is expected to p rogress at coating film film break s; (4) (4) discoloration discoloration is n o t ed e d a n d m a y or o r m a y n o t b e a n a p p e a ra ra n c e factor; and (5) (5) m od erate to significant significant met al loss is is noted . This op tion is cond ucive to coatings that ar e in in p oo r co n d it io n an d ar e n o l o n g er p r ot ec t in g t h e s u b s t r a t e . T h is is o p t io io n r e q u i r es es f u l l rem oval of all the existing coating ma terial and recoating the entire surface. C o m p l e t e r e m o v a l a n d r e co co a t i n g i s a v i ab ab l e o p t i o n f o r at at m o s p h e r i c a n d i m m e r s i o n s e r v i ce ce exposures.
51. Material Selection Factors.— T h e r e a r e n u m e r o u s f a c to to r s to to b e c o ns ns i d e r e d w h e n selecting selecting a coating to m eet sp ecifi ecificc cond itions. itions. T h e m o s t b a s i c fa fa c t o r i s th th e e n v i r o n m e n t t h e coating w ill be subjected subjected to (e.g., (e.g., atm atm osph eric, b u r i a l, o r i m m e r s io n s u r f a ce e x p o s u r e ) . (Se e chap ter I, su su bsection bsection 6, “Service “Service Exp Exp osur es.”) es.”) Coatings should be selected for their intended u se (i. (i.e. e.,, a coating form ulated for for atm osph eric service exposu re is not suitable for i m m e r s io io n ) . T h e f o ll ll o w i n g a r e s o m e o t h e r f a ct ct o r s t o b e t a k e n i n t o c o n s i d e r a t i o n w h e n selecting selecting a coating m aterial:
(a) Coating Properties.— • • •
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A b ra r a s io io n or o r e r os os io i o n re re s is is t an an c e A d h es e s i on on of o f pr p r im ime r A p p e a r a nc nce
(c) Environmental.— •
T em e m p e r at a t u re r e a n d hu h u m i di d i ty ty e x xtt re r e m es es a n d v a r ia i a t io io n s
•
C av av it it a ti ti o n. n.
•
C h em em i ca ca l c o n ta ta ct ct
•
T r a ff ff i c, c, fo fo o t o r ve v e h ic ic l e
Accessible structures a re 52. Scheduling.— Accessible relatively easy to sched sched ule for insp insp ection and m a i n t e n a n c e co a t i n g w o r k . H o w e v e r , m a n y R e cl cl a m a t i o n s t r u c t u r e s s u c h a s i nt nt e r i o r o f t u r b i n e s , p u m p u n i t s , p e n s t o c k s , d r a ft ft t u b e s , d i s c h a r g e l in in e s , a n d o t h e r i n t e r i o r w a t e r b e a r i n g s u r fa c es a r e d i ffi c u l t t o a cc es s w i t h o u t a s ch ch e d u l e d o u t a g e a n d m a n y a r e a s ca ca n n o t b e d ew atered in excess of 5 years. There fore, p l a n n e d o r u n p l a n n e d o u t a g e s s h o u l d b e t a k e n a d v a n t a g e o f fo fo r e i t h e r i n s p e c t io io n o r c o a t in in g s work. I n s ch ch e d u l i n g a p l a n n e d o u t a g e t o p e r f o r m m a i n t e n a n c e co co a t i n g w o r k , t h e r e v e n u e l o ss ss i n e l e ct ct r i ci ci t y o r w a t e r d e l iv iv e r y n e e d s t o b e accoun ted for since reven u e loss loss w ill likely likely b e co m e a sig n i fic a n t fa ct o r .
Chapter XI Galvanizing Galvani zing is the app lication lication of zinc zinc onto a steel sur face. Zinc is an od ic to steel (i.e (i.e., ., zinc w ill sacrifice itself itself to prote ct steel from corrosion). Reclamation specifies numerous s t e e l m e t a lw lw o r k i te te m s t o b e g a l v a n i z e d . M e t a l w o r k i t e m s m a y r a n g e f r o m s m a l l i te te m s such, as bolts and nu ts, to large items, such as gates. The followi followi ng are reasons to coat coat over galvan izin izin g: (1) to form form a barrier coating in bu ri al or im m e rs i on se rv ice ic e e xp os u re s b ec a u se t h e z i n c w i ll ll b e r a p i d l y c on on s u m e d ; ( 2) 2) t o r e p a i r d a m a g e d a r e a s ; a n d ( 3 ) t o im im p r o v e
aesthetics (color (color ap pe aran ce). Coating over galvanized surfaces presents unique p roblems that ar e ch ch aracteristic of zinc and the coating material selected.
53. Galvanizing Methods.— T h e r e a r e s e v e r a l m e t h o d s t o u s e w h e n a p p l y in in g z i n c . T a b l e 3 p r o v i d e s t h e m o s t co m m o n m e t h o d s fo r g a l v a n i z in in g an an d i n c lu lu d e s m a n u f ac ac t u r i n g p r oc es se s, sp ec if ic a ti o n r ef e r en ce s , z in c c oa ti n g thicknesses, an an d ty pical app licati lication on s for for each method:
Table 3.—Galvanizing methods Method
Process
Specifications
Thickness
Typical application
Electrogalvanizing
Electrolysis
ASTM A 591
Up to 0.14 mil
Interior service exposure: a pp ppliance panels, studs, and acoustical ceiling members
Zinc plating
Electrolysis
ASTM B 633
0.2 to 1.0 mil
Interior or exterior service exposure: fasteners and hardware items
Mechanical plating
Peening
ASTM B 695
0.2 to 4.0 mil
Interior or exterior service exposure: fasteners and hardware items
Continuous galvanizing
Hot-dip
ASTM A 653
Up to 4.0 mil
Interior or exterior service exposure: roofing, gutters, culverts, automobile bodies
Hot-dip galvanizing
Hot-dip
ASTM A 123 ASTM A 153
1.4 1.4 to 5.0 5.0 mil mil
Inte Interi rior or or exte exteri rior or serv servic ice e expo exposu sure re:: nearly all shapes and sizes, ranging from nails, bolts, and nuts to large structural items
Thermal Spraying
Hot zinc spray
AWS C2.2
3.3 to 8.3 mil
Interior or exterior service exposure: items that cannot be galvanized by other methods because of their size and shape or because galvanizing must be performed onsite.
Zinc-rich painting
Brush, roller, airless, or conventional spray
0.6 to 5.0 mil per coat
Interior or exterior service exposure: Items that cannot be galvanized by other methods because of their size and shape or because galvanizing must be performed onsite. Aesthetics (color).
Varies with owner's or manufacturer’s specifications
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Guide to Protective Protective Coatings: Coatings: Inspection and Maintenance M o s t R e cl cl a m a t i o n g a l v a n i z e d m e t a l w o r k i t e m s that require painting are by the hot-dip p r o c e ss . T h is m e t h o d r e q u i re s t h e m e t a lw o r k i te te m s t o b e i m m e r s e d i n a b a t h o f m o lt lt e n z i n c t h a t c la la d s t h e m e t a l w o r k s u r f a ce ce i n a n e a r l y p u r e z in c la y e r .
54. Zinc Corrosion and Service Life.— Life.—Zinc, b y i t se lf, d o e s n o t co r r o d e lik li k e s t e el. el . C o r r o s i o n of zinc is achieved by exp osing zinc to oxygen a n d m o i s t u r e . Th e r e s u l t is is a w h i t e c o r r o s io io n b y p r o d u c t . Ba r e g a lv a n i z ed m e t al w o r k i m m e r s e d i n s e a w a t e r m a y l a st st f o r 6 m o n t h s b e fo r e b e in g c o n s u m e d . Ba r e g a lv a n i z in g m a y l a s t 5 t o 1 0 y e a r s in in f r e s h w a t e r , d e p e n d i n g o n the water chemistry. H ow ever, bare g a l v a n i z in in g i n a n a t m o s p h e r i c s er er v i c e e x p o s u r e w i ll ll fo fo r m a p r o t e c t iv iv e l a y e r b e t w e e n 1 an an d 2 years after the initial galvanizing p r o c e s s, a n d t h i s p r o t e c t iv e l a y e r i m p e d e s furthe r corrosion. The service lif lifee of atmosp heric galvanized metalw ork has been k n o w n t o e x c e e d 5 0 y e a r s. s.
a n d s e co co n d p h a s e r e a ct ct i o n s m a y c o n t i n u e f o r 1 t o 2 y ea ea r s a f t e r th th e g a l v a n i ze ze d m a n u f a ct ct u r i n g p r o ce s s i s fin i sh e d , d e p e n d in g o n t h e lo ca l e n v i r o n m e n t . Z i n c c a r b on on a t e ( t h ir ir d p h a s e reaction) is a dense , insoluble m aterial that forms the prot ective ective layer. The final final g a l v a n i z e d s u r f a c e is is a d u l l m a t t e g r a y . Z i n c o x i de de , z i n c h y d r o x i d e , a n d z i n c ca ca r b o n a t e p r o d u ct s d o n o t f o rm u n ifo if o rm l y o ve r th e g a l v a n i ze ze d s u r f a ce ce o r t o a u n i f or or m d e p t h . A l l t h r e e p r o d u c t s ar ar e a w h i t is is h c o lo lo r a n d n e a r l y i m p o s si si b l e to to v i su su a ll ll y d i st st in in g u i sh sh f ro ro m e a c h o t h e r . W i t h o u t k n o w i n g w h i c h z in in c c o m p o u n d i s p r e s e n t , co co a t i n g o v e r g a l v a n i z e d s u r f a c es es b e co co m e s p r o b l e m a t i c .
56. Contaminants.— C o n t a m i n a n t s o n g a l v a n i z e d s u r f a ce ce s a r e z i n c a s h r e s id id u e s d e p o s i te te d d u r i n g t h e g a l v a n iz i n g p r o c e s s a n d n a t u r a l o cc cc u r r i n g w h i t e o x id id e s t a in in t h a t fo r m s d u r i n g s t o r a g e . T h e fo fo l lo lo w i n g t w o s e c t io io n s p ro v i d e a m or e d e ta i l ed d e sc ri pt i on of zi nc a sh a n d s t o ra ra g e s t a i n c on on t a m i n a n t s .
55. Zinc Chemical Reactions.— Zinc is an a c t iv iv e m e t a l a n d w i ll ll r e a c t w i t h o t h e r e l em em e n t s t o fo fo r m o x i d e s an an d c o m p o u n d s . T h e f o l lo lo w i n g z i n c co co m p o u n d s a r e fo f o r m e d o n t h e g a l v a n i z ed ed surface: •
Z in i n c ox ox id i d e is i s fo f o r m e d a b ou ou t 24 24 to t o 48 48 h o u r s a ft ft e r t h e g a l v a n i z i n g p r o c e s s b y t h e r e a c t i on on o f z i nc nc w i t h o x y g e n i n t h e air.
•
Z in in c h y d r ox o x id id e is i s f o rm r m e d b y th th e r e a c t io io n o f t h e z i n c w i t h m o i s t u r e f r o m rain, dew, or high cond ensation.
•
Z in in c ca ca r bo b o n a te te is is fo fo rm rm e d b y t h e r e a c ti ti o n o f z i n c o x id id e a n d z in in c h y d r o x i d e w i t h c a r b o n d i o x id id e f r o m f r e e f lo lo w i n g a i r .
Zinc oxide (fi (first rst ph ase reaction reaction ) an an d zin c h y d r o x id id e (s e co co n d a r y p h a s e r e a c t io io n ) a r e p r o d u c t s t h a t ar e w a t e r so lu b l e an d n o t v e r y d e n s e . T h e s e p r o d u c t s a dh dh e r e v e r y lo lo o s e l y t o t h e s u b s t r a t e su su r f a c e . P a i n t d o e s n o t a d h e r e w e l l t o z i n c o xi xi d e a n d z in c h y d r o x i d e , a n d p a in ti n g ov er th es e m a te r ia ls w il l p r ob a b ly resu lt in prem atu re coating failure. failure. The first
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(a) Zinc Ash.— I n t h e g a l v a n i z i n g p r o c e s s , p a r t ic le s o f o x id iz e d z in c flo a t o n t h e s u r f a ce o f t h e m o lt lt e n b a t h . W h e n t h e m e t a l w o r k i s r e m o v e d f r om om t h e b a t h , r e si si d u e o f o x id id i z e d z i n c p a r t i cl cl e s c a n r e m a i n o n th th e m e t a l w o r k . A t h i n l a y e r o f r e s id id u e c a n f o r m o n t h e s u r f a ce ce , a n d t h i s r e s id id u e i s r e f e r r e d t o a s “ z i n c a s h . ”
(b) Wet Storage Storage Stain.— Stain.— N e w l y g a lv a n i z e d i t e m s a r e s t o r e d a n d s h i p p e d . If t h e s t o r a g e area or shipping container preven ts the circulation circulation of carbon dioxide in free free flow ing air c o n d i t i on on s , a w h i t e r u s t w i ll ll fo fo r m o n t h e galvan ized surface. This is a natu ral p rocess t h a t i s o ft ft e n r e f e r r e d t o a s “ w h i t e s t o r a g e stain.” W hite stora ge stain stain results from a lack o f ca ca r b o n d i o x id id e t o c o n v e r t z i n c o xi xi d e a n d z i n c h y d r o x i d e t o t h e s t a b l e z i nc nc c a r b o n a t e c o m p o u n d . I f l e ft ft u n c h e c k e d a n d s u f f ic ic ie ie n t m o i s tu tu r e i s p r e s e n t , a ll ll t h e z i n c m a y b e c o n s u m e d ( r a r e o cc cc u r r e n c e ) , o r t h e z in c m a y b e co n s u m e d in p a t ch y a r e a s , o r t h e r e su lt m a y be r e d u c e d z i nc t h i ckn ck n e ss . T o p r e v e n t w h i t e s t o r ag ag e s t a in in , m a n u f a ct ct u r e r s m ay p erform a posttreatment process. The
Galvanizing f o ll ll o w i n g a r e t h e m o s t c o m m o n p o s t t r e a t m e n t m e t h o d s a n d t h e i r e ff ff e ct ct s o n p a i n t in in g :
Ap pl y a co atin g o f oi l to form fo rm a ba rrie rr ie r s, from moisture.— moisture.— P a i n t s w i l l n o t a d h e r e t o o i l s, a n d a p p l y in in g o i l w i ll ll r e s u l t in in a d h e s i o n f a il il u r e if the oil is not rem oved . To check for the p resence of oil, oil, perform a w a t e r b ea ea d t e st st . P la la c e a d r o p o f w a t e r on on t h e surface. If the w ater bead s, it ind icates the p r es en ce o f o il .
forma tion of reactive reactive zinc oxide and zinc hyd roxide comp oun ds. The c h e m i c a l r e a c ti tio n m a y c o n t i n u e f o r 1 t o 2 years, dep end ing on local weather conditions and m etalwork geometry.
• Weather Weathered ed gal galvani vanized zed metalwor metalwork.— k.— The surface has completed chemical c o n v e r s io io n f r o m z in in c ox ox i d e a n d z in in c h y d r o x i d e c o m p o u n d s t o n o n r e a c t iv iv e zinc carbonate. still (a) Newly Galvanized Galvanized Metalwork.— Metalwork.— Zin c is still
Quenching (cooling in a water bath).— W a t e r m a y c o n t a i n g r e a s e a n d o i ls ls t h a t f lo lo a t o n t h e w a t e r su su r f a c e a n d c o n t a m i n a t e t h e galvan ized sur face, face, resu resu lting lting in coating a d h e s i o n f a i lu lu r e i f t h e g r e a s e a n d o i l a r e n o t removed.
Chromate quenching.— Typi cally, paints w i ll ll n o t a d h e r e t o g a l v a n i z e d s u r f a c e s t r ea ea t e d b y th is m et h od . Ch r om a te q u en ch in g is b ei n g d i s c o n t in in u e d b e c a u s e o f h u m a n s a f e ty ty a n d e n v i r o n m e n t a l c o nc nc e r n s . Phosphate quenching.— A d h e s i o n o f p a i n t i s im im p r o v e d b y t h i s m e t h o d . T h e r e i s n o e a s y f ie ie l d t e s t t o d e t e r m i n e t h e type of quench treatm ent that w as used, if any. T h e m o s t r e l ia ia b l e m e t h o d i s t o c o nt nt a c t t h e g a l v a n i z in in g s h o p .
(c) Deposited Contaminants.— D e p o s i t e d c o n t a m i n a n t s a r e f o r e ig ig n s u b s t a n c e s t h a t a c c u m u l a t e o n t h e g a l v a n i z e d s u r f a ce ce . T h e most comm on contam inants are d irt, grease , oil, and soluble salts. C hlorid e salts salts are a g g r e s s iv iv e l y d e s t r u c t iv iv e t o g a l v a n i z e d m e t a l w o r k . F or or p r o t e ct ct i on on a g a i n st st c h l or or i d e c o n t a m i n a t i o n , g a lv lv a n i z e d i t e m s s h o u l d b e p r o t e ct e d b y c o n t a in e r s d u r i n g t r a n s p o r t o r storage.
r e a c t iv iv e o n n e w l y g a lv lv a n i z e d m e t a l w o r k , a n d several contam inan ts may exist, such as oil c o a ti ti n g o r p o s t t r e a t m e n t a p p l ie ie d a t t h e p o in in t of galvaniz ing. Each Each specific specific contam inant ma y r e q u i r e a s p e c ia ia l iz iz e d s u r f a c e p r e p a r a t i o n m e t h o d . T h e f o l lo lo w i n g s t e p s a r e su su r f a c e p r ep a r a ti o n m et h od s f o r r em ov a l o f s p ec ific if ic contaminants:
Removal of w hite storage storage stain (white rust), if present.— A p p l y a 1 - t o 22- p e r c e n t a m m o n i a s o l u t io io n b y b r u s h o r s p r a y . F o r s e v e r e w h i t e storage stain , app ly 1 part a cetic or citric acid acid t o 2 5 p a r t s o f w a t e r . T h o r o u g h l y r in in s e t h e a r e a w h e r e t h e s o lu lu t i o n w a s a p p l ie ie d w i t h w a r m p o t a b le w a t er a n d a llo w t h e a r ea t o a ir d r y .
Removal of dirt, grease, and o il.— Solvent cleaning cleaning in accordan ce with SSPC-SP1. SSPC-SP1. W ater b a s e d e m u ls ifi e r s a n d a l k a lin e c le a n e r s h a v e b ee n sh ow n to w or k b es t. En su r e t h a t a lk a li n e c le le a n e r s h a v e a p H o f l e s s th th a n 1 2 b e ca ca u s e z in in c w ill ill dissolve in highly alkaline solutions. A p p l y c le le a n i n g s o l u t i on on s b y d i p p i n g , s p r a y i n g , o r b r u s h i n g w i t h s o ft ft b r i st st l e b r u s h e s . D i p p i n g a n d s p r a y in i n g w o r k s b e st st w h e n t h e cleaning solution is at abou t 140 to 185 d egrees F . T h o r o u g h l y r in in s e th th e a r e a w h e r e t h e s o lv lv e n t w a s a p p l i e d w i t h h o t p o t a b l e w a t e r a n d a l lo lo w t h e a r e a t o a i r d r y .
Removal of zinc ash.— A p p l y a 1 - t o
57. Surface Preparation.—T h e m e t h o d o f surface preparation of galvanized m etalwork b ef o re p a in ti n g d e p en d s on w h e t h er th e m e t a l w o r k is is n e w l y g a lv lv a n i z e d o r w e a t h e r e d :
• Newly Newly galvani galvanized zed metalwor metalwork.— k.— Th e s u r f a ce ce i s u n d e r g o i n g t h e a c t iv iv e
2 -p -p e r c e n t a m m o n i a so so l u t i o n b y b r u s h o r s p r a y . T h or or o u g h l y r in in s e t h e a r e a w h e r e t h e a m m o n i a s o lu lu t i o n w a s a p p l ie ie d w i t h w a r m p o t a bl bl e w a t e r a n d a l lo lo w t h e a r e a t o a i r d r y .
Repair of physical defects (high spots and cu r w h e n e x c e s s z i n c droplets).— H i g h s p o t s o c cu
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Guide to Protective Protective Coatings: Coatings: Inspection and Maintenance r u n s d o w n t h e e d g e s o f m e t a lw lw o r k a s it it is is r e m o v e d f r o m t h e m o l t e n t a n k . T h e e x c e ss ss z i n c fo fo r m s p r o t r u s io io n s o r i r r e g u l a r e d g e s . High spots should be ground off with a pow er t o o l . D r o p l e t s fo fo r m a t m e t a l w o r k e d g e s w h e r e z i n c d r a i n s w h e n t h e m e t a lw lw o r k i s re re m o v e d f r o m t h e m o l t e n b a t h . D r o p l e t s ca ca n b e g r o u n d d o w n o r k n o c k e d o f f b y p o w e r t oo oo l s. s. W h e n u s i n g p o w e r t o o l s, s, d o n o t g r i n d o f f t h e z i n c t o l e s s t ha ha n t h e r e q u i r e d t h i c k n e s s . If the zinc on metalwork ha s been removed to b a r e m e t a l o r t h i n n e d b e l o w t h e s p e c if ied ie d t h i c k ne ne s s d u r i n g s h i p p i n g , c o n s t r u c t io io n , h a n d l in in g , o r i n s t a ll ll a t io io n , t h e d a m a g e d g a l v a n i ze ze d a r e a s ca ca n b e r e p a i r e d b y c oa oa t i n g w i t h a z i n c -r -r i ch ch p r i m e r .
Removal of zinc oxide and zinc hydroxide ti v e z i n c o x id id e a n d z in in c compounds.— T h e r e a c ti h y d r o x i d e co c o m p o u n d s m a y n o t h a v e b ee ee n c o m p l et et e ly ly r e m o v e d d u r i n g t h e i n i ti ti a l cl cl ea ea n i n g p r o c e ss , a n d t h e r e is n o s im p le fie ld d e t e ct io n m e t h o d . T o a v o i d p r e m a t u r e c o a t in in g fa fa i lu lu r e , t h e c oa oa t i n g i n d u s t r y r e c o m m e n d s o n e o f t h e f in in a l s u r f a ce ce p r e p a r a t i o n m e t h o d s b e e m p l o y e d t o r e m o v e r e a c t i v e z in in c o x id id e a n d z i n c h y d r o x i d e co co m p o u n d s ; h o w e v e r , t h e c o a t in in g m a n u f a ct ct u r e r s h o u l d b e c o n s u l t e d be b e fo r e a p p ly i n g t h e p r i m e r b e c a u s e so m e o f the method s may not be comp atible with the z i n c -r -r i ch ch p r i m e r :
Phosphate treatment.— A p p l y a p h o s p h a t e c o n t a i n in in g s o lu lu t i o n t o f o r m a n o n r e a c ti ti v e z i n c p h o sp h a t e l a y e r o n t h e su r fa c e a n d i n h i b it t h e f or or m a t io io n o f z i n c ox ox i d e s . T h e t r ea ea t m e n t w i ll ll s li li g h t l y e t ch ch t h e s u r f a c e , p r o d u c i n g a n a n c h o r p r ofil of il e fo r th e c o a ti n g p r im er . A p p li ca t io n is by i m m e rs i on , sp r ay , or so ft b r i st le br u sh . Th e solution is left left on for about 3 to 6 m inu tes and r i n s e d o ff ff w i t h p o t a b l e w a t e r . C o l or or a t i o n i s r e t u r n e d t o t h e g a l v a n i z e d s u r f a ce ce a f te te r w a s h i n g s o t h a t a n y m i s se se d a r e a s w i ll b e v i s ib ib l e a n d c an an b e r e t re re a t e d . A l l ow ow t h e s u r f a c e to air dry be fore coating. For new construction metalwork items that are s p e c i fi fi e d t o b e c o a t e d , p h o s p h a t e q u e n c h i n g a t t h e g a l v a n i z i n g p l a n t w i l l p r o d u c e h ig ig h e r q u a l i t y a n d a t l e s s co co s t t h a n a p p l i c a t io io n i n t h e field. field.
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Z i n c -r -r ic ic h p r i m e r s h o u l d n o t b e a p p l i e d t o p h o sp h a t e t r e a t e d s u r f a c e s . T h e p h o sp h a t e w i ll ll fo fo r m a n i n s u l a t e d b a r r i e r b e t w e e n t h e z in in c p a in t p a r ti cle s a n d th e z in c g a lv a n iz e d m e ta l. To be effecti effective, ve, zinc-rich zinc-rich p rimer s requ ire direct c o n t a c t b e t w e e n t h e z i n c p a r t ic ic le le s i n t h e p a i n t a n d t h e z i n c m e t a l o n t h e g a l v a n i z e d s u r f a ce ce . in g Wash primers.— W a s h p r i m e r s a r e c o a t in m a t e r i a ls ls f o r m u l at at e d t o n e u t r a l iz iz e s u r f a ce ce z i n c o x i d e s a n d z i n c hy hy d r o x i d e s a n d t o e t c h t h e galvanized surface, prod ucing an anchor p r o f il e for fo r t h e c o a t in g p r i m e r . Ty p i ca l ly , t h e m a n u f a ct ct u r e r r e c o m m e n d s a s in in g l e th th i n co co a t be b e a p p l ied ie d b y b r u s h o r s p r a y a t a b o u t 0 .3 t o 0.5 0.5 mils. At this thickness, the galvan ized s u r f a c e sh sh o u l d s h a d o w o r r e t a i n a n e a r m a t t e gray app earance. If the galvanized surface b e c o m e s h i d d e n , t h e w a s h p r i m e r w a s a p p l ie d t o o t h i c k ly ly , a n d i t m a y d e l a m i n a t e b e c a u s e o f t h e w a s h p r i m e r ’s ’s p o o r co h e s i v e s tr tr e n g t h . A c o m m o n w a s h p r i m e r i s p o l y v in in y l b u t y r a l (SSPC (SSPC Paint Specification Specification N o. 27) 27).. Oth er w ash p r im er fo r m u la t io n s a r e co m m er ci al ly available. ca t i on on o f a n a c i d i c Acr ylic yli c pas p as sivatio siv atio n.— A p p l i ca acrylic solut solut ion wi ll passivate or neu tralize the r e a c t iv iv e z i n c o x id id e s a n d z i n c h y d r o x i d e s a n d r o u g h e n t h e s u r f a c e, e, p r o d u c i n g a n a n c h o r p r ofil of il e fo r th e c o a ti n g p r im er . Th e s ol u ti o n is ap plied at abou t 0.0 0.04 4 mil (1 (1 micron micron ). This m e t h o d i s c o n s id id e r e d a p p l ic ic a b le le o n l y f o r v e r y t h i n l a y e r s o f z in in c o x id id e s a n d z i n c h y d r o x id id e s . T h e s o lu lu t i o n m u s t b e d r y b e f o r e a p p l y i n g a n y coatin coatin g ma terial. terial.
Sw eep blas tin g.— This is a light blast c le le a n i n g m e t h o d t o r e m o v e t h e r e a c ti ti v e z i n c o x id id e s a n d z i n c h y d r o x id id e s a n d t o p r o d u c e a n anch or profile profile for for the coatin coatin g prim er. Soft Soft a b r a s i v e s sh sh o u l d b e u s e d t o r e d u c e s ig ig n i f ic ic a n t z i n c m e t a l l os os s a n d s h o u l d h a v e a M o h s ’ s ca ca le le hard ness of 5 or less and a part icle icle size b e t w e e n 8 t o 20 m il s . T y p ic a l a b r a siv si v e s ar e a l u m i n u m o r m a g n e s i u m s i li li ca ca t e , co co r n c o b s, s, w a l n u t s h e l l , l im im e s t o n e , a n d s o m e m i n e r a l sands.
Galvanizing T h e b l a s t n o z z l e s h o u l d b e h e l d a t a r e l a t iv iv e l y l o w a n g l e t o r e m o v e t h e r e a c t iv iv e z i n c o x id id e s a n d z i n c h y d r o x i d e s . H o l d i n g th th e b l a s t n o z z l e p er p en d ic u la r to th e s u r face fa ce ca n q u ic k ly r e m o v e s o u n d z i n c m e t a l. l. O p t i m a l a m b i e n t c o n d i t i on on s f o r s w e e p b l a st st i n g a r e 7 0 d e g r e e s F a n d 5 0 p e r c e n t o r l e ss ss r e la la t i v e h u m i d i t y . A f t e r s w e e p b l as as t in in g , c o a t t h e s u r f ac ac e w i th th i n 24 hou rs.
(b) Weathered Galvanized Metalwork.— Fully w e a t h e r e d g a l v a n i z in in g w i th th a n o u t d o o r e x p o s u r e o f b e t w e e n 1 a n d 2 y ea ea r s s h o u l d h a v e c o m p l e t el el y c on on v e r t e d t h e z i n c o x id id e a n d z i n c h y d r o x i d e co co m p o u n d s t o f o r m a s t a b l e (nonr eactive) eactive) p rotective lay lay er of zinc c ar ar b o n a t e . T h e m o s t c o m m o n su su r fa fa c e p r e p a r a t i on m e t h o d is w a t e r p o w e r w a s h in g a t a p r e s s u r e o f a b o u t 1 ,4 ,4 50 50 p s i t o r e m o v e d i r t , g r e a s e , a n d o i l. l. H i g h e r p r e s s u r e s s h o u l d b e avoided to redu ce the risk of removing sound z i n c . Sw e e p b l a s t in in g i s a n o t h e r m e t h o d u s e d , often u sed after water pow er washing to p r o m o t e a d h e si o n o f t h e p r im e r .
Ag ed or we athe at he red galva ga lva ni ze d me talw ork .— O l d , a g e d g a l v a n i z i n g t h a t h a s b ee n in se r v ic e f o r se v er a l y ea r s a n d is s h o w i n g e v i d e n c e o f d e t e r i o r at at i o n p r e s e n t s a d d i t io io n a l p r o b l e m s a n d r e q u i r e s r e m e d i a l s u r f a c e p r e p a r a t i o n m e t h o d s d i ff ff e r e n t f r o m t h o s e a p p r o p r i a t e fo fo r n e w l y g a lv lv a n i z e d metalwork. Deteriorated areas may show a redd ish-brown stain. This color color stain stain m ay be mistak en for corrosion of the steel ba se metal. Just ab ove t h e i n t e r f a ce ce b e t w e e n t h e s t e e l b a s e m e t a l a n d t h e z i n c t h a t w a s a p p l i ed ed d u r i n g t h e h o t d i p galvan izin izin g p rocess, a zinc-iron zinc-iron alloy alloy layer is forme d. The zinc-iron zinc-iron alloy layer may be corroding rather than the steel base metal, and be b e b l e e d i n g t h r o u g h t h e m o r e p u r e z i n c a b o v e , r e s u l t in in g i n t h e r e d d i s h - b r o w n s t a i n . Z i n c -i -i r o n alloy alloy is brow nish, and steel corrosion corrosion is red d ish. It is difficult difficult to visually distingu ish t h e d i f fe fe r e n c e b e t w e e n t h e t w o m e t a l s b y color. A m a g n e t i c o r e l e ct ct r o n i c D F T g a u g e c a n b e u s e d t o d e t e r m i n e i f t h e s t e e l b a se se m e t a l o r t h e
zinc-iron zinc-iron alloy is corrod ing. Since Since zin zin c is is n o n m a g n e t i c, c, m e a s u r i n g o v e r z i n c w i ll ll p r od u ce a th ic k n es s r ea d in g . A r ea d in g show ing thickness indicates galvanized m aterial is present (i.e., (i.e., brow nish co lor) (hot d i p g a l v a n i z in in g i s a p p l ie ie d a t a t h i c k n e s s o f a b o u t 2 t o 5 m i l s ). ). R e a d i n g s t h a t s h o w n o thickness ind icate icate ferrou s rust (i.e. (i.e.,, redd ish color color ind icates icates zin zin c has been con con sum ed ). This i s im im p o r t a n t b e c a u s e t h e a r e a s t h a t a r e b r ow n ish is h m a y st il l h a v e s u ff ic ie n t g a lv a n iz in g ma terial left left intact, and this wi ll affect affect the surface prep aration requ irements. The surface prep aration of old, aged g a l v a n i z i n g r e q u i r e s t h e f o ll ll o w i n g s t e p s : 1 . W a t e r p o w e r w a s h th t h e e n t i r e s u r f ac ac e to to r e m o v e d i r t , o i l, l, a n d g r e a s e a t a b o u t 1,450 psi. 2 . A b r a s iv iv e ly l y b l as as t ( N A C E 3 / S S PC PC - SP SP 6) 6) or p ow er tool (SSPC-SP3 (SSPC-SP3 or SSPC-SP11) SSPC-SP11) c le le a n t h e r u s t e d r e d d i s h a r e a s ( li li t t le le o r n o g a l v a n i z in in g i n t a c t ) t o b a r e s t e e l a n d f e a t he he r t h e e d g e s . 3 . H a n d ( SS SSP C - SP SP 2) 2) o r p o w e r t o ol o l cl cl e an an (SSPC-S (SSPC-SP3) P3) the brow nish-colored are as ( g a lv lv a n i z i n g i n t a c t ), ), e n s u r i n g n o m o r e g a l v a n i zi zi n g i s r em em o v e d t h a n i s necessary. 4 . Sw e e p b l a s t t h e en en t i r e g a l va va n i z e d surface to promote the ad hesion of the p r i m e r c o a t .
58. Coatings.— N u m e r o u s c oa t in g m a t e r ia ls c a n b e a p p l i ed ed o v e r g a l v a n i z in in g ; h o w e v e r , i t is is b es t t o e n su r e t h a t t h e m a te r ia l s el e ct e d is c o m p a t i b le le w i t h z i n c . T h e s e le le c t io io n d e p e n d s not on ly on comp atibility atibility bu t also, in certain certain cases, on chem ical ical treatm ents, su su rface p r ep a r a ti o n , a n d se r v ic e e xp os u r e. C on su lt t h e c o a t in in g m a n u f a ct ct u r e r o r t h e s p e c if if ic ic p r o d u c t d a t a s h e e t s fo r c o m p a t i bi lit li t y w i t h specific specific cchem hem ical ical trea trea tm ents and surface p r e p a r a ti o n m e th o d s . follow ing coatings (a) Coating Selection.— The follow a r e s u i t a b le le t o o v e r c o a t g a lv lv a n i z i n g u n d e r
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Guide to Protective Protective Coatings: Coatings: Inspection and Maintenance a t m o s p h e r i c , bu bu r i a l , a n d i m m e r s io io n s e rv rv i c e c o n d i t i on on s : •
•
Bu r i a l o r im im m e r si si o n s e rv rv ic i c e ex e xp o s u r e "
Coal tar epoxy
"
Epoxy
"
M o i st st u r e c u r e d u r e t h a n e
"
Z i n c -r -r i ch ch e p o x y fo fo r d a m a g e d a r e a s
"
Z i n c -r -r i ch ch m o i s t u r e c u r e d u r e t h a n e f or or d a m a g e d a r e a s
A t m o sp s p h er e r ic ic se s e r v ic ic e e xp xp o su su r e or w ater-born e acrylic " Acrylic or " Acrylic latex
at e x " W a t e r b o r n e l at "
58
Zinc-rich Zinc-rich aerosol spray for rep airing d a m a g e d a r e a s o f ba ba r e g a l va va n i z e d surfaces
"
E p o x y p r i m e r w i t h U V - r e s is is t a n t a l ip ip h a t i c u r e t h a n e t o p c o a t
"
M o i st s t u r e - cu cu r e d u r e t h a n e p r i m e r w i t h U V - r e si si st s t a n t a li p h a t i c u r e t h a n e topcoat
"
Z i n c -r -r i ch ch e p o x y o r m o i st st u r e - c u r e d u r e t h a n e p r i m e r w i t h U V - r e s is is t a n t c o m p a t i b le le t o p c o a t fo fo r d a m a g e d areas
D o n o t u s e o i ll-b a s e d o r a l k y d c o a t i n g s u n l e s s they are sp ecifical ecifically ly formu lated for galvan izing. Zinc is an alkaline alkaline m etal. M o i s t u r e w i l l ev ev e n t u a l l y p e r m e a t e t h r o u g h t h e coating film film . The zinc and bind ers in in oil-based oil-based o r a l k y d c o a t i n g s r e a c t in in t h e p r e s e n c e o f a l k a li li n i ty ty a n d m o i s t u r e t o f o r m a m e t a l li li c soap . This p rocess is is called sapo nification. nification. C a s e h i s t o r ie ie s s h o w t h a t o i ll- b a s ed ed a n d a l k y d c o a t in in g s t h a t a r e a d h e r i n g w e l l w i ll ll r e q u i r e a b o u t 6 m o n t h s t o 1 y e a r a ft ft e r a p p l ic ic a t io io n i n a n o u t d o o r e n v i r o n m e n t t o b e g i n t o f ai ai l. l.
Chapter XII Coating Failures Coatings fail for man y reasons. These failures failures can be related to m aterial selection, selection, f o r m u l a t i o n , a d h e s i o n , s u b s t r at at e t y p e , ap plication, stru stru cture d esign, or exterior forces. forces. These related failure typ es may act i n d e p e n d e n t l y o f e a c h o th th e r o r i n c o n c e r t w i t h e a c h ot ot h e r . T he he r e a d e r i s s t r o n g l y u r g ed ed t o p u r ch a se on e o f t h e p h ot og r a p h ic co a ti n g fa i lu lu r e b o o k s l is is t e d in a p p e n d ix B . ct t h e 59. Material Selection.— T o p r o t e ct substr ate, coatings coatings are requ ired to resist d e t e r io io r a t i o n f r o m a t m o s p h e r i c , b u r i a l, l, a n d i m m e r s io io n s e r v i ce ce e x p o s u r e . N o o n e t y p e o f c o a t in in g h a s e v e r b e e n d e v e l o p e d t o p r o t e c t e d all sub strate typ es in in all service exposu res. R a t h e r , m a n u f a c tu tu r e r s fo r m u l a t e co co a t i n gs gs f o r specific specific service exposu res. Coating m aterial selection selection is generally based on serv ice e x p o s u r e s u i t a b i li li t y, y, p a s t h i s t o r y p e r f o r m a n c e , r e c om om m e n d a t i on on s f r o m o t h e r f a c il ili t y o w n e r s , a n d a c c e le le r a t e d p e r f or or m a n c e t e s t s. s. T h e f o ll ll o w i n g a r e s o m e e x a m p l e s of of im im p r o p e r m aterial selection: selection: •
•
•
S e le le ct ct io io n of o f a pa p a i nt n t fo fo r th th e w r o ng ng service expo expo sure. For examp le, if an atm osph eric coating coating is specified specified for imm ersion service exposu exposu re, failure failure w ill occu occu r in a relatively relatively shor t time p e r io d . S e le le ct ct io io n o f a p ai a i n t ba b a s ed e d s o le l e ly ly o n costs. costs. N ot all p aints are equ al. A m a n u f ac a c tu tu r e r m a y p r o d u c e s o m e e x c e ll ll e n t p r o d u c t s b u t o t h e r p a i n t s f ro r o m t h e s a m e m a n u f a c tu tu r e r m a y n o t p e r f or m w e ll. A s a r u l e-o e- o f-t h u m b , w h a t y o u p a y f o r is is n o r m a l l y w h a t y o u get, and this, in general, app lies lies to p a i nt m a t e r i a ls . S e le le ct ct io io n o f a p a in in t b a s ed e d s o le le ly ly o n a n uns ubstantiated opinion. A person
w i t h li li m i t e d k n o w l e d g e o f i n d u s t r ia ia l c o a ti ti n g s c a n s e l ec ec t t h e w r o n g o r p o o r l y p er for fo r m in g m a te r ia ls , r e su lt in g in p r e m a tu r e fa ilu r e . •
S e le le ct ct io io n o f a p ai a i n t sy s y s te t e m t h at a t i s no no t comp atible w ith another paint. For e x a m p l e , a c o a t in in g p r i m e r m a n u f a ct ct u r e d b y o n e c o at at in in g c o m p a n y should not be topcoated w ith a m aterial m a n u f a ct ct u r e d b y a d i ff ff e re re n t c o m p a n y , e v e n i f t h e t w o c o a t in in g m a t e r i a l s a r e o f the sam e generic type, such as a p o ly a m id e e p o x y . In c o m p a t ib i lit y o f s o l ve ve n t s b e t w e e n t w o s i m i la la r p a i n t s is is a c o m m o n c a u s e fo fo r p r e m a t u r e f a il il u r e .
60. Formulation.— F o r m u l a t i o n f a i lu lu r e s a r e f ai ai lu lu r e s t h a t a r e i n h e r e n t w i th th i n t h e c o a t in in g ma terial itself. itself. The com com po ne nts of a coating coating consist of resin resin s, solven ts, and pigm ents, and t h e y a r e m i xe xe d i n v a r i o u s p r o p o r t i on on s . I m p r o p e r c o m p o n e n t m i x tu tu r e d u r i n g t h e m a n u f a ct ct u r i n g p r o c e s s ca ca n l e a d t o f a il il u r e . F o r m u l a t io io n f a i l ur ur e s a r e s u b d i v i d e d i n t o t h e f ol ol lo lo w i n g o r g a n i c an an d i n o r g a n i c c oa oa t i n g classes: ( a) Fo rm ulatio ula tio n - O rgan ic Co atin gs .— O r g a n i c coatings can fail becau se of chan ges in f o r m u l a t i o n , ra ra w m a t e r i a ls ls , i m p r o p e r p r o p o r t i o n i n g , in s u f fic i e n t m i ll ing in g , a n d o t h e r m a n u f a c tu tu r i n g p r o c e s s es es , . T a b le le 4 p r o v i d e s a d escription of form form u lation for for organ ic failures, t h e c a u s e o f fa fa i lu lu r e , a n d t h e r e m e d y f o r t h e failures.
(b) Formulation - Inorganic Zinc.— Zinc.— I n o r g a n i c c o a t in in g s s u f f e r fr fr o m i n h e r e n t p r o b l e m s t h a t resu lt in in failu failu res caused principal ly by silicate silicate v e h i c le le s a n d m e t a l li li c zi zi n c t h a t a r e u s e d i n t h e i r c o m p o s it it i o n . T a b l e 5 p r o v i d e s a d e s c r i p t i o n o f t h e t y p e s a n d c au au s e s o f in in o r g a n i c z in in c c oa oa t i n g f a i lu lu r e s a n d t h e r e m e d i e s f o r th th e f a i lu lu r e s .
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Guide to Protective Protective Coatings: Coatings: Inspection and Maintenance Table 4.—Formulation-related failures for organic coatings (modified from SSPC, Good Painting Practice, Practice, volume 1, third edition, 1997) Failure description
Cause
Remedy
Internal stress where surface shrinks more rapidly than the body of the coating. coating. Hard topcoat applied over soft undercoat.
Remove failed coating. Apply thin coats and thoroughly dry before applying additional coats. Never apply hard topcoat (epoxy) over soft coats (asphalt).
CHALKING - Surface is soft, powdery, and easily removed by wiping.
Surface disintegration caused by UV sunrays on an organic resin binder; formulated with improper pigmentation.
Select coatings formulated with UVresistant resins (acrylics) and light stable, high hiding pigments.
CHECKING - Surface phenomena with uneven, small, noncontinuous fissures in coating that do not penetrate to the substrate.
Surface stresses resulting from shrinkage caused by weathering and continued coating polymerization and oxidation.
Select a coating formulated with weather-resistant resins, inert reinforcing pigments, and light stable pigments.
CRACKING - Small breaks in coating to substrate. May be linear, cross-hatched, or curved. Cracks may or may not be continuous.
Stress set up in coating because of continued polymerization and oxidation; improper pigmentation or improper coating system.
Select coating formulated from nonreactive, weather-resistant resins; reinforcing pigments; and nonreactive colored pigments. Primer must be compatible with intermediate and finish coats.
DISCOLORATION - Yellowing, graying, or darkening of coating.
Resin or pigment color change caused by weather or chemical reaction.
Select coating formulated with both color stable resins and pigments.
EROSION - Similar to chalking. Surface removed on high spots and brush marks to base or primer coating.
Chalking mechanism, coating surface removed by weathering and abrasion.
Select a tough, chalk-resistant coating with good flow out characteristics that will form a smooth film.
MICROORGANISMS - Blotchy brown or black spots on coating surface causing poor, dirty appearance with softening or slimy feel.
The biodegradation of the coating by bacteria or fungi. Bacteria or fungi use coating ingredients for nourishment.
Use oil coatings containing permanent fungicide or bactericide. Nonoil coatings should use modifiers that will not biodegrade.
MUD CRACKING - Large cracking. Coating may curl at cracks and lose adhesion.
Rapid drying of high filled coatings, especially waterbased materials (water emulsion paints).
Select coatings with strong adhesion. Apply coatings under proper drying conditions and avoid sags or areas of excess thickness during application.
WRINKLING - Furrows and ridges in coating surface. surface. May be linear or random pattern. Wrinkle may be fine or quite large.
Surface reaction where surface of coating expands more rapidly during drying than does the body of the film.
ALLIGATORING - Very Very large macrocracking, generally crosshatched pattern.
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Select coating with even, thorough drying characteristics. Apply evenly and avoid excessive thickness.
Coating Failures Table 5.—Formulation-related failures for inorganic zinc coatings (modified from SSPC, Good Painting Practice, Practice, volume 1, third edition, 1997) Failure description
Cause
CHECKING - Usually fine, visible, or microscopic checks. Does not penetrate to the substrate.
The zinc pigment to binder ratio is high, causing rapid drying and resulting in surface cracking.
Formulation should include reinforcing pigments. Apply coating as thin as recommended. Apply second coat only if necessary. necessary. Apply under favorable conditions.
CHEMICAL - Pinpoint rusting progressing from spotty to continuous area.
Acid or alkali reaction on both silicate binder and metallic zinc.
Apply resistant topcoats over inorganic zinc coatings.
MUD CRACKING - Fine to fairly large segments, about 1/4-inch across, flaking from the coating surface.
Application too heavy or drying too rapidly.
Apply coating at no more than recommended thickness and apply under favorable drying conditions.
PINPOINT RUSTING RUSTING - Pinpoint spots of corrosion progressing from a few spots per square foot to almost continuous rusting.
Uneven coating thickness. Thinly coated areas show failure first. This is a normal failure pattern for inorganic zinc coatings.
61. Adhesion.— A d h e s i o n fa fa i lu lu r e s a r e n u m e r o u s a n d c a n b e c a t a st st r o p h i c . F a il il u r e s a r e c au au s e d f o r a n u m b e r o f r ea ea s o n s. s. O n e o f t h e m o s t co co m m o n r e a s o n s fo fo r a d h e s i on on f ai ai lu lu r e i s p a in ti n g o v e r a co n ta m in a te d su b st r a te . C o n t a m i n a t e d su su r f a ce ce s p r e v e n t a d h e s io io n . Soluble salts salts left on the surface pro m ote o s m o t i c b li li s t e r in in g w h e r e m o i s t u r e o r g a s e o u s v a p o r is t r a n s m i tt tt e d t h r o u g h t h e s e m i p e r m e a b l e c o a ti ti n g m a t e r i a l , a n d g a s e s o r l iq iq u i d s c a n f o r m b e t w e e n t h e c o a ti ti n g a n d t h e sub strate. Table 6 pro vid es a description of t h e t y p e s a n d c a u s e s o f a d h e s i o n f a il il u r e s a n d the rem ed ies for for the failu failu res.
Remedy
Apply a maintenance coat at first sign of pinpoint failure.
m o s t c o m m o n s u b s t r a t e s a r e s t e e l, l, c a st st i r o n , a l u m i n u m , z i n c , c o p p e r , c o n cr cr e t e , a n d w o o d . These substrat es all all have different characteristics, characteristics, su su ch as d ensity, porosity, and chem ical ical reactivity. reactivity. Steel is is very den se ( r e la la t e d t o s u r f a ce ce s m o o t h n e s s ), ), n o n p o r o u s , a n d l e ss ss c h e m i c a l ly ly r e a c t i v e t h a n o t h e r s u b s t r a t e m a t e r i a ls ls . O n t h e o t h e r h a n d , c o n c r e t e is is n o t a h i g h d e n s i t y (n (n o n u n i fo fo r m e d s u r f a c e ) m a t e r i a l; l; it it i s p o r o u s a n d v e r y chem ically ically reactive. This simp lified lified c o m p a r i s o n i ll ll u s t r a t e s t h e d i ff ff e r en en c e s b e t w e e n s u b s t r a t e t y p e s . T a b le le 7 p r o v i d e s a d e s c r i p t io io n o f t h e t y p e s a n d c a u s e s o f s u b s t r a t e fa fa i lu lu r e s a n d t h e r e m e d i e s f or or t h e f a i lu lu r e s .
62. Substrate.— T h e t y p e o f s u b s t r a t e s u r f a c e can be a factor related to coating failur failur es. The
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Guide to Protective Protective Coatings: Coatings: Inspection and Maintenance Table 6.—Adhesion-related failures (modified from SSPC, Good Painting Practice, Practice, volume 1, third edition, 1997) Failure description
Cause
Remedy
BLISTERING - Small to large (1/32 to 1 inch plus) hemispherical bubbles in the coating that contain gases or liquids. Bubbles may range from 1 per square foot to several hundred per square foot.
Blisters may be due to poor surface preparation, internal soluble materials (salts), or poor wetting of substrate. Osmosis causes absorption of gases into substrate or solvent entrapment (also referred to as “solvent blistering”).
Select a coating with very strong adhesion strength and low moisture vapor transfer rate. Ensure clean substrate with proper surface preparation and reduced soluble salt levels to suit service exposure.
FLAKING or SCALING - Small to large (1/16 to 1 inch plus) pieces of coating, curling at edges. Easily removed from surface, leaving substrate exposed.
Normally, coating is brittle, with internal shrinkage characteristics and marginal adhesion strength. Oil type coatings may scale or flake from galvanized surface (never apply an alkyd to a galvanized surface).
Select a coating with very strong adhesion strength and low moisture vapor transfer rate. Ensure clean substrate with proper surface preparation and reduced soluble salt levels to suit service service exposure. For galvanized surfaces, use a primer compatible with zinc.
INTERCOAT DELAMINATION Coatings that do not adhere to the previous coat. Failure is between the primer and the intermediate coat or between the intermediate coat and the top coat. The substrate is not normally exposed.
Coating material is not compatible with undercoat; undercoat surface may be contaminated with dust, dirt, overspray, or other contaminates; or undercoat may have cured beyond maximum recoat time.
Select a coating with good compatibility and adhesion between coats. Ensure that that the undercoat surface is clean before applying the next coat. For epoxies, do not expose to moisture (water and humidity) or excessive sunlight before applying the next coat.
PEELING - Coating may be smooth and lying on the surface or hanging in shreds. Little or no adhesion is evident.
Adhesion is less than the tensile strength of the coating. Coating peelings can easily be pulled from the surface down to bare substrate.
Select a coating with very strong adhesion strength and low moisture vapor transfer rate. Ensure that the substrate is clean, the surface has been cleaned properly, and salt has been reduced to levels suited to the service exposure.
UNDERCUTTING - Corrosion byproducts from the substrate build up under the coating and will break the coating at edges or pinholes. The corrosion progresses under the coating.
Poor adhesion because of improper surface preparation (dirt, dust, soluble salts, other contaminates); smooth surface (no surface profile); or coating incompatibility with the substrate surface.
lu r e s a r e m o s t 63. Application.— C o a t i n g f a i lu c o m m o n l y r e la la t e d t o t h e m e t h o d o f ap plication. There are a variety of reasons for a p p l ic ic at at i o n - re re l a t e d f ai ai lu lu r e s t h a t h a v e n o t h i n g t o d o w i t h m a t e r i a l s e le le c t i on on o r i m p r o p e r f o r m u l a t i o n . T h e s e fa fa i lu lu r e s a r e m a i n l y ca ca u s e d b y h u m a n s. T h e r e a r e n u m e r o u s e xa m p le s,
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Select a coating with very strong adhesion strength. Apply coating over a surface that that has has been abrasively cleaned or cleaned by water jet blasting. Use of a zinc-rich primer reduces undercutting.
r a n g i n g f r o m f a il il u r e t o u n d e r s t a n d t h e c o n s e q u e n c e s of of im im p r o p e r l y p r e p a r i n g s u r f a c e s t o i m p r o p e r l y a p p l y i n g c o a t in in g s t o ru shing the job. job. Table 8 pr ovid es a description of app lication lication failures, failures, the cau se of the failures, failures, a n d t h e r e m e d y f o r t h e fa fa il il u r e s
Coating Failures Table 7.—Substrate-related failures (modified from SSPC, Good Painting Practice, Practice, volume 1, third edition, 1997) Failure description
Cause
Remedy
AGED STEEL - The surface includes blisters, rust, pitting, tubercles, or adhesion loss in areas where the substrate was exposed to a corrosive environment.
Substrate surface retained minute corrosion byproducts or contaminants even if it was abrasively blasted or water jet blasted to a high degree of cleanliness.
Water jet blast surface with water; dilute phosphoric acid; or saltbonding, chemical-removal solution. Apply an anticorrosion primer or barrier coating with high adhesion strength.
AGED CAST IRON - The surface includes blisters, rust, pitting, tubercles, or adhesion loss in areas where the substrate was exposed to a corrosive environment. A silver gray to a dark gray color may indicate graphite corrosion. This kind of corrosion can be easily cut or pierced with a knife.
Cast iron has a rough, more porous, crystalline surface matrix than steel, causing more moisture to be retained.
Water jet blast surface with water or salt-bonding chemical removal solution. Heat surface to hot-tohot-totouch to drive off moisture. Brush apply primer while surface is warm to allow a maximum wet-coat penetration. Select compatible intermediate coat and/or topcoat.
GALVANIZED or METALLIC ZINC - White zinc corrosion byproduct developing under or breaking through the coating.
Formation of zinc salts (oxide, sulfide, oxychloride, zinc soaps) under the coating.
Brush or low-pressure water-jet blast zinc surface or treat with commercial zinc treatment solution. Select an inert, nonoil primer with high adhesion strength.
ALUMINUM - White aluminum corrosion by-product is causing pinpoint coating failure, adhesion loss from smooth surface, blistering, or pitting.
Environmental pH outside the range of 5 to 8.5. 8.5. Lack of accessible oxygen. oxygen. Lack of adhesion to a very smooth aluminum oxide surface, i.e., lack of sufficient surface profile.
Light dust blast or soft abrasive blast or treat with commercial aluminum treatment solution. Select a compatible primer with high aluminum surface adhesion strength.
COPPER - Blue or gray-green corrosion by-products, adhesion failure blistering, or pitting.
Lack of adhesion to a very smooth copper surface (no surface profile) or the presence of oxides on surface.
Light brush blast, soft abrasive blast, or treat with commercial copper treatment solution. Select a compatible primer with high copper surface adhesion strength.
CONCRETE - Adhesion loss, blistering, or peeling of coating.
Abrasive blast or water jet blast Chemically reactive and high (acid etching not recommended) to moisture content. Formation of obtain clean and dry surface. calcium salts under the coating. Select a low molecular weight, high Pinholes, air, and water pockets in concrete surface. Water vapor penetrating primer with high alkali resistance (coal tar epoxy or transmission through concrete. modified epoxy).
For graphite corrosion, it is the selective leaching of ferrous ions from some cast irons, normally gray cast iron.
64. Design.— N u m er ou s c o a ti n g fa il u r es o c c u r , n o t b e c a u s e o f m i s fo fo r m u l a t e d m a t e r i a l s, s, deficient surface preparation, or application e r r o r s b u t b e c a u s e o f t h e i n h e r e n t l y d i ff ff ic ic u l t p ro b l e m s p r e s e n t e d by t h e d e si gn o f t h e s t r u c t u r e . M o s t d e s ig ig n e r s d o n o t h a v e c o r ro ro s i o n m e c h a n i s m s a n d c o a ti ti n g o p e r a t i o n s
i n m i n d w h e n t h e y d e ssii g n s t r u ct c t u r e s. s. H o w e v e r , w i t h t h e p r o p e r s e le le c t io io n o f c o a t in in g m a t e r ia ia l s a n d a p p l i c a ti ti o n t e ch ch n i q u e s , m a n y d e s ig ig n i n a d e q u a c i e s ca ca n b e o v e r c o m e . T a b l e 9 p r o v i d e s a d e s c r ip t i o n o f d e si gn f a i lu re s, t h e c a u s e o f t h e f ai ai lu lu r e s , a n d t h e r e m e d y f o r t h e failures.
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Guide to Protective Protective Coatings: Coatings: Inspection and Maintenance Table 8.—Application-related failures (modified from SSPC, Good Painting Practice, Practice, volume 1, third edition, 1997) Failure description
Cause
Remedy
IMPROPER MIXING MIXING - Coating is too thin, pigment distribution is nonuniform, or both. Entire or localized areas may have poor adhesion, uneven color, checking, or cracking.
Failure to sufficiently mix material, resulting in improper pigment-tovehicle ratio; settled pigment remains in bottom of container.
Thoroughly mix the liquid material to an even, smooth, homogeneous consistency, with no color variation. During use, continue mixing as necessary. Mechanical mixing is the preferred method.
IMPROPER THINNING - Poor adhesion or pigment flotation, resulting in uneven color. Separation of pigment and vehicle after application, resulting in pinholing or blushing.
Thinner is incompatible with resins or pigments. Improper drying, resulting in surface tension change. Thinner evaporated too rapidly causing moisture to condense on liquid coating. Excessive thinner, resulting in curdling or flocculation of pigment.
Use only the manufacturer’s recommended thinner for selected coating material in the amounts specified. Add thinners thinners slowly and mix thoroughly.
IMPROPER ENVIRONMENTAL CONDITIONS - Blistering and/or poor adhesion caused by damp, humid conditions. Powdery coating where drying occurred too rapidly (overspray). (overspray). Soft, uncured coating.
Ice, moisture, condensation (above dew point), or standing moisture on surface before application. Lack of proper cure because the temperature and/or humidity were outside restrictive range.
Apply coatings using the manufacturer’s environmental (temperature, humidity, dew point, and surface condition) restrictions or more restrictive requirements.
IMPROPER THICKNESS Where coating is thin, pinpoint corrosion areas result. Where coating is overly thick, checking, cracking, or flaking result.
Improper applicator technique: too close or too far away during spraying; incomplete or excessive spray passes. Difficult areas (restrictive accessibility or space).
Use proper application techniques for even passes and overlaps, follow the manufacturer’s application instructions, and use the equipment recommended by the manufacturer.
AMINE BLUSHING - Oily, ambercolored film on coating surface for aliphatic, amine-cured epoxy materials.
Material applied relatively thickly on cold, damp days or in similar environments where amine rises to surface and reacts with carbon dioxide and moisture in the air.
Wait for proper temperature and humidity before application.
BLUSHING - Milky or whitish appearance of coating film with a dull or flat finish.
Moisture condensation on coating in high humidity because of fast evaporation or unbalanced thinners. Occurs most often on hot, humid days or in similar environments.
Wait for improved humidity, reduce atomizing air pressure to a minimum, or add evaporation retardant to thinner.
BLEEDI BLEEDING NG - Stai Staining ning of of topco topcoats. ats.
Soluble Soluble resin resins s or pigm pigments ents in in undercoat migrate to topcoat.
Seal undercoat with coating in which bleeding components are insoluble.
CRATERING - Small, uniform indentations in coating film (also referred to as “pitting”).
Air pockets trapped in wet film during spray application.
Abrasive blast, water jet blast, or roughen affected area; ensuring removal of contaminants within craters; and reapply coating.
FISHEYES - Separation or pulling apart of wet film to expose underlying coat or substrate.
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Coating applied over dirt, oil, silicone, or incompatible coating material.
Remove all material by abrasive blasting or water jet blasting, ensue substrate is contaminant free, and reapply coatings.
Coating Failures Table 8.—Application-related failures (modified from SSPC, Good Painting Practice, Practice, volume 1, third edition, 1997) Failure description
Cause
HOLIDAYS - Bare areas on the substrate that were not coated by the applicator (also referred to as “painter’s holiday”).
Improper and inconsistent application technique, reflecting a lack of care. Most often occurs in areas difficult to coat.
LIFTING - Wrinkling, swelling, or blistering appearance on the film surface.
Solvents in a coating attack or swell the underlying coating, resulting in film distortion.
Remove all material by abrasive blasting or water jet blasting and reapply coatings.
ORANGE PEEL - Overall appearance is bumpy. Film surface is smooth but irregular. Resembles skin of an orange.
Inherent with sprayed-on materials; caused by improper application techniques: gun too far from surface, solvent evaporation too rapid, spray pressure too low for proper atomization, paint particles falling outside of spray pattern, or material too viscous.
Brush out excess paint before material cures. Correct spray technique. After material has cured, sandpaper surface before applying another topcoat that reacts more slowly.
OVERSPRAY - Very rough coating surface. Surface may be dry, pebbly, or sandy. Some coated areas may have the appearance of dryness or feel dry (also referred to as “dry spray”).
Improper application techniques: gun too far from surface, solvent evaporation too rapid, spray pressure too low, atomizing pressure too high, paint particles falling outside of spray pattern, or material too viscous.
Before the material cures, remove the overspray by dry brushing, followed by solvent wiping. After the material has cured, wire screen and sandpaper the surface before applying another topcoat that reacts more slowly.
PINHOLES - Small, tiny, deep holes (1/32 inch) in coating, normally through to the substrate. Generally, the distribution of holes appears to be random.
Improper application techniques: gun too far from surface, solvent evaporation too rapid, spray pressure too low, atomizing pressure too high, paint particles falling outside of spray pattern, or pigment settlement.
Correct any improper application techniques. If pinholes already exist and the material has not cured, apply additional coat by brushing into holes. If material has has cured, but it is still within the recoat window, apply an additional additional coat. If outside the recoat window, abrade surface and apply additional coat.
RUNS or SAGS - Downward movement of coating material on vertical or curved surfaces in the form of droplets or streams. Runs are the result of excess material continuing to flow after the surrounding surface has set. Sags are the result of differences between application and setting times. Sags have have the appearance of a curtain.
Excessive application of coating material, spray gun too close, too much thinner, surface too hard or glossy to hold material, or temperature too cold for proper drying.
Correct any improper application techniques. Apply thinner coats. If material has not cured, brush out excess material. If material has cured and is still within the recoat window, apply an additional additional coat. If outside the recoat window, abrade surface and apply additional coat.
Note: Orange peeling is not a coating failure, but the appearance may be objectionable.
Remedy Apply coating in a careful and professional manner, consistent with industry standards.
65
Guide to Protective Protective Coatings: Coatings: Inspection and Maintenance Table 8.—Application-related failures (modified from SSPC, Good Painting Practice, Practice, volume 1, third edition, 1997) Failure description
Cause
SPATTER COAT - Areas of thin coating (less than specified coating thickness), normally at end of the spray pass or around complex sections of structure. Under good lighting conditions, coating appears continuous; under poor lighting, coating appears discontinuous. May develop into pinpoint corrosion at a later date.
Improper application techniques, causing a noncontinuous coating over the surface: inconsistent spray passes not overlapping by 50 percent, spray gun flipped at end of spray pass, or spray gun not held perpendicular to the surface.
Remedy Correct any improper application techniques. If material has not cured, apply additional coat. If material has cured but it is still within the recoat window, apply an additional coat. If outside the recoat window, abrasive blast or water jet blast all material off and recoat.
Table 9.—Design-related failures (modified from SSPC, Good Painting Practice, Practice, volume 1, third edition, 1997) Failure description BACK-TO-BACK ANGLES and PLATES - Corrosion between back-to-back angles and plates is resulting in undercutting of coating.
Cause Impossible to apply coating in crevice between angles and plates.
Remedy Design: Use T bar or pipe in construction. Precoat: Coat angles and plates before construction assembly. Stopgap measure: Fill crevice with with resinous chalking and topcoat with compatible material.
EDGES - Linear corrosion along edge and undercutting coating away from the edge.
Surface tension causing coating to pull away from edges.
Brush or stripe coat surfaces before full coating. Overlap full coating on both sides of edges. Spray directly at edge to build up thickness and reduce surface tension.
INTERIOR CORNERS - A void or blister is developing under coating.
Excessive coating thickness, resulting in coating shrinkage during or after curing.
Apply multiple thin coats and allow coating to thoroughly dry between coats, but within recoat window.
SKIP WELDS - Corrosion in weld gaps and between overlapping metal is causing undercutting of coating.
Impossible to apply coating in crevices in weld gaps and between metal surfaces.
Provide continuous weld in gaps and overlap areas before applying coating in any corrosive environment.
SMALL DISCONTINUOUS AREAS - Corrosion is developing on edges of bolt heads, bolt threads, nuts, washers, rivets, and other small edged or cornered surfaces.
Small surfaces with high ratio of edges and corners to plain, flat area will increase coating surface tension and cause coating to pull away from edges and corner points.
Brush or stripe coat surfaces prior to full coating. Overlap brush or stripe coat with each full coat applied. Applying multiple thin coats is more beneficial than one thick coat.
66
Coating Failures Table 9.—Design-related failures (modified from SSPC, Good Painting Practice, Practice, volume 1, third edition, 1997) Failure description
Cause
Remedy
STORAGE TANK ROOFS (Interior of umbrella type for center post and rafters) Corrosion is developing between roof and rafter and between lapped roof plates.
Impossible to apply coating in crevices between roof and rafter and between lapped roof plates.
Butt weld or double weld roof plates. Precoat rafters and underside of roof.
WELDS - Corrosion along welds, particularly hand welds, is undercutting coating away from weld. Corrosion along weld may be continuous or discontinuous.
Welding flux in undercuts along weld. Rough weld surfaces. surfaces. Soap remaining after pressure testing of welds. Blue scale (similar to mill scale) remaining on weld surface.
Remove all soap solution and blue scale. Grind rough rough welds smooth smooth or nearly smooth. smooth. For interior of hydraulic structures, such as pipelines, grind welds down to 1/8 inch, minimum. Abrasive blast weld and apply brush or stripe coat 2 to 3 inches on each side of weld, working coating into all rough areas before applying full coating.
65. Exterior Forces.— T h e e n v i r on on m e n t t h e
w a t e r t h a t c o n t a i n s a b r a s iv iv e m a t e r i a l s u c h a s sand pa rticles. rticles. In this section, section, ord ord inary a t m o s p h e r i c e x p o s u r e s a r e n o t c o n si si d e r e d . Table 10 10 prov ides a d escription of failures failures related to exterior forces, the cau se of the f a il il u r e s , a n d t h e r e m e d y f o r t h e f a il il u r e s
coating is sub sub ject to can can be a p rimary cause of f ai ai lu lu r e . C o r r o s i v e e n v i r on on m e n t s n o r m a l l y e n c o u n t e r e d o n R e c la la m a t i o n p r o j e ct ct s a r e f r e s h w a t e r e n v i r o n m e n t s t h a t c o n t a i n v a ri ri o u s c o n c e n t r a t io io n s o f d i s s o lv lv e d s a lt lt s a n d f lo lo w i n g
Table 10.—Failures related to exterior forces (modified from SSPC, Good Painting Practice, Practice, volume 1, third edition, 1997) Failure Description
Cause
Remedy
Wear caused by wheeled traffic, impact, wind, or liquid-borne abrasives.
Select coating with strong adhesive properties and specific abrasion and erosion resistance. Thoroughly prepare surface (nearwhite blast minimum) and apply new coating.
CAVITATION CAVITATION - Lo ss of coating and metal material. Appears as tiny craters overlain by multiple craters in metal surface, accompanied by significant metal loss.
Drop in water vapor pressure, forming air bubbles that repeatedly collapse at high pressure.
Select coating with strong adhesive properties and high cavitation resistance.
CHEMICAL - Dissolution of coating; undercutting or underfilm corrosion.
Selection of unsuitable coating material. Improper coating application.
The prime requirement is to select a coating for the specific chemical service exposure.
ABRASION or EROSION EROSION Thinning or wearing away of coating is resulting in a bare substrate subject to corrosion.
67
Guide to Protective Protective Coatings: Coatings: Inspection and Maintenance Table 10.—Failures related to exterior forces (modified from SSPC, Good Painting Practice, Practice, volume 1, third edition, 1997) Failure Description
Cause
Remedy
FAYING SURFACES - Coating failure and corrosion in joint area.
Concentration (or crevice) corrosion caused by oxygen differences between closely spaced or joined coated surfaces, subject to friction-producing movement (e.g., steel plates and high strength bolts).
Precoat metal surfaces before assembly with inorganic zinc coating or a suitable coating with a high coefficient of friction.
GRAFFITI - Painted words or graphics over coated surface.
Vandals painting coated surfaces, especially with spray cans.
Select the manufacturer's graffiti remover and antigraffiti coating
68
Bibliography Bechtel Pow er Corp oration, Steel Steel Stru Stru ctures Painting Council, Coating and ts b u r g h , Lin in g I n sp ection M an u al , P i t ts Penn sylvania, 1991. 1991. Bookcock , Simo Simo n K., R.E.F. R.E.F. We aver , B. Ap plem an, and G.C. Soltz, Soltz, Eff ects on Surface Contaminants on Coating Life. Bechtel Pow er Corp oration, Steel Steel S t r u c t u r e s P a i n t i n g C o u n c i l, l, P i tt tt s b u r g h , Penn sylvania, 1991. 1991. D e p a r t m e n t o f th th e N a v y , Pai nt Failu res il Causes and Remedies , N a v y C i v il E n g i n e e ri ri n g L a b o r a t o r y , P o r t H u e n e m e , Californ ia, 1982. 1982. Electrical Electrical Pow er Research Institute, Inc., Inc., Steel Steel Pen stock Coating and Lining Lining Rehabilitation: A H y dr opow er Tech n olog y R oun du p R epor t , volu m e 3, TR-11358 TR-113584, 4, Pleasa nt H ill, California, 2000. 2000. F it it z i m o n s , B r e n d a n , Pro t ecti v e Coat in g Robinson Irw in In sp ection M an u al , Robinson Technical Sup por t Ltd Ltd ., England , 1997 1997.. F it it z i m o n s , B r e n d a n , V isual Com Com parison parison M anu al: A ppl ica tion an d C oat in g D efects. R o b in in s o n I r w i n T e c h n i ca ca l S u p p o r t L t d . , England , 1998. 1998. Generic Generic Coatin Coatin g T ypes: A n Int rodu rodu ction ction to In du st ria l M ain t ena n ce Coa tin g M ater ials , Smith, Lloyd Lloyd M., ed., Technology P u b l is is h i n g C o m p a n y , P it it t s b u r g h , Penn sylvania, 1996. 1996.
M u n g e r , C h a r l e s G . , Corrosion Prevention by P rotective rotective Coatin Coatin g , Nat ional Association of Corrosion Engineers, Hou ston, Texas, Texas, 1984. N A C E I n te r n a ti o n a l, N A CE Corr osion En gin eer' s R eferen ce Book , second e dition, R.S. R.S. Tresed er, R. Baboian , and C.G. M un ger, ed s., s., Hou ston, Texas, 199 1991. 1.
N a ti o n a l A ss o cia ci a ti o n o f C o r r o sio n En g in e e r s, Corrosio Corrosion n Basics: Basics: An Int rodu rodu ction ction , H o u s t o n , Texas, 1984. The Society of Protective Coatings, Good lu m e 1 , th th i r d e d i t io io n , Pain t in g P ract ices , v o lu John D . Keane, Keane, Dean Berger, Haro ld H o w e r , Be Be r n a n d R . A p p l e m a n , Jo s e p h Brono, Kitti Kitti Cond iff, iff, Mark O 'Donn ell, ell, Janet Rex, Aim ee Beggs, Vilm Vilm a Mac ura, T e r r y So So w e r s , a n d M o n i ca ca M a d a u s , e d s .,., Pittsbur gh, Penn sylvan ia, 199 1993. 3. The Society of Protective Coatin gs, Steel Steel Structures Painting Council, Systems and io n , Specifications , v o l u m e 2 , s e v e n t h e d i t io B er er n a r d R . A p p l e m a n , Ja Ja n e t R e x , a n d Terry Sowers, eds. Pittsburgh, Penn sylvania, 1995. 1995. The Society Society of Pr otective Coating s, T he In sp ection of C oati n gs an d L in in gs: A H and bo ok of Basic Pract ice f or In spe ctors , O wn ers, ers, and S pecifie pecifiers, rs, Be r n a r d R . A p p l e m a n , Ri Ri ch ch a r d W . D r i s ko ko , Ju Ju d i t h K . N e u g e b a u r , Sim o n K . Boo k c o c k , R u s s e l Davi son, Lawren ce J. J. Grabiak, CIH, CSP, Janet Janet Rex, and Terry Sow ers, ed s., s., Pittsburg h, Penn sylvania, 1997 1997.. The Society Society of Protective Coa tings, C-1: Fu n da men t als of P rote cti ve Coat ing s for In du st rial S tru ctu ct u res , version 10, Pittsburg h, Penn sylvania, 1999 1999.. The Society Society o f Protective Coatin gs, C-3: Supervision/Competent Person Training for D eleadin g of In du st rial S t ru ctu res , t w o volum es, version V7-T, Pittsburgh , Penn sylvania, 1999. 1999. The Society Society of Protective Coatin gs, C-2: Specifying Specifying and M anaging Protective Protective Coating Coating tw o v o l u m e s , v e r s io io n 7 , Proj ects , tw Pittsburg h, Penn sylvania, 200 2000. 0.
69
Guide to Protective Coatings The Society Society o f Protective Coatin gs, SS PC-V IS 2: Standard M ethod ethod of Evaluating Evaluating D egree of R u st in g on Pain t ed S t eel S u rfaces , Pittsburg h, Penn sylvania, 2000 2000..
ts b u r g h , Pre par ed by W ate rjett in g , P i t ts Penn sylvania, 2001. 2001.
The Society Society of Protective Coa tings, Surface Pre para tio n S pecif icati ons , P i t t s b u r g h , Penn sylvania, 2000. 2000.
The Society Society o f Protective Coatin gs, SSPC-V IS 5/N A CE V IS 9: Guide and R eferen ce Pho tog rap hs for S teel S u rfaces Pr ep ared by W et A br asive Bl ast C lean in g, Pittsbur gh, Penn sylvania, 2001 2001..
The Society of Protective Coatings, SSPC-V IS 4/N 4/N A CE V IS 7: 7: Guide and R eferen ce Ph otograp ot ograp hs f or S t eel S u rfaces
The Society Society o f Protective Coatin gs, SS PC-S P 15: Com Com m ercia erciall Grade Power T ool ool Pittsbu rgh , Pen Pen nsylvan ia, 2002. 2002. Cleaning, Pittsbu
70
Appendix A Organizational Sources for Standards and Refer ences Am erican Society Society of Testing Testing an d M aterials (ASTM) (ASTM) 1916 Race Stree t Philad elph ia PA 191 19103 03 Telep hon e: (610) (610) 832-9500 832-9500 Fax: (610) 832-9555 W e b s i t e A d d r e s s : w w w . a s tm tm . o r g N A CE In te r n at io n al (N A C E) PO Box 218340 218340 H ou ston TX 77218 77218 Telep hon e: (218) (218) 228-6223 228-6223 Fax: (281) 228-6329 W e b s i t e A d d r e s s : w w w .n a c e .o .o r g Society Society for P rotective Coa tings (SSPC) (SSPC) th th 40 24 Street, 6 Floor Pittsbur gh PA 15222 15222 Telep hon e: (412) (412) 281-2 281-2331 331 ext 16 Fax: (412) 281-992 W e b s i t e A d d r e s s : w w w . s sp sp c . o r g Bureau o f Reclam Reclam ation Guide Specifications W e b s it it e A d d r e s s: s: h t t p : / / i n tr tr a .u .u s b r .g .g o v / g u i d e s p e cs cs
A-1
Appendix B Reading Sources Good Painting Pra ctice, Steel Stru Stru ctures Painting M anu al, Volum e 1, Third Ed ition, ition, 1993. 1993. (The (The fourt h ed ition ition is du e in 2003. 2003.)) System System s and Specific Specifications, ations, Steel Steel Stru Stru ctures Pa inting M anu al, Volum Volum e 2, 2, Eighth Eighth Edition, 2000 2000.. Coating an d Lining Insp ection Man ua l, Bechtel Corp oration, 1983, 1983, exclusively d istributed b y Steel Structur es Paintin g C ou ncil (SSP (SSPC), C), Au gu st 1991, 1991, SSP SSPC C P u blication blication N o. 9191-12 12.. The Inspection of Coatings and Lin Lin ings, A H and book of Basic Basic Practice for for Inspectors, O w ners, an d Specifiers, SSPC SSPC P u blication N o. 91-1 91-12, 2, First First Ed ition, 1997. 1997. C o r r o s i o n P r e v e n t i o n b y P r o t e c t iv iv e C o a t i n g s , b y C h a r l e s G . M u n g e r , Pu Pu b l i s h e d b y N A C E Inter na tion al, First Ed ition, 1984. 1984. P a i n t in in g : N e w C o n s t r u c t io io n a n d M a i n t e n a n c e, e, U . S . A r m y C o r p s o f En En g i n e e r s , M a n u a l N o . E M 1 11 11 00- 223400, Ap ril 30, 1995. 1995. F H W A F i e ld ld M a n u a l fo r B r i d g e P a i n t I n s p e c t io io n , U . S. S. D e p a r t m e n t o f T r a n s p o r t a t i o n , F e d e r a l H i g h w a y A d m i n i st st r a t io io n ( FH FH W A ) , F H W A B ri ri d g e C o a t in in g s T e c h n o l o g y T e a m , O c t o b e r 1 99 99 7. 7. S t ee ee l P e n st st o c k C o a t i n g a n d L in in i n g R e h a b i l it it a t i o n , A H y d r o p o w e r T e c hn hn o l o g y R o u n d u p R e p o r t , Volu m e 3, 3, Tech Tech nical Rep ort TR-113584 TR-113584-V3, -V3, Au gu st 2000. 2000. Av ailable from from Electric Electric Power Re search Institute ( EPRI), EPRI), 341 3412 2 Hillview Av enu e, Palo Alto CA 94304; 943 04; telep ho ne : (650) (650) 855-2000 855-2000;; C u stom er Service: (800) (800) 313-3774 313-3774;; W ebsite A d d ress: www.epri.com V is is u a l C o m p a r i s o n M a n u a l , A p p l i ca ca t i on on a n d C o a t in in g s D e fe fe c t s , B re re n d a n F i tz tz i m o n s , R o b i n so so n I rw rw i n Technical Support Ltd., England 1997-1998, (SSPC Publication No. 00-8)
B-1
Appendix C Inspection Checklist G
D e li li v e r e d m a t e r i a ls ls
G
A p p r o v e d m a t e r ia i a l s, s , r e co co r d b a t c h n u m b e r s to r e d p r o p e r l y G S to G Containers secured
life not exceeded G Shelf life G
Abrasive material SSPC-AB1, Class Class A, Type I or II G Com plies w ith SSPC-AB1, G Contaminants
oil, ASTM D 4940 G Ch eck for pr esence of oil, Chlor*Rid A test kit G Check for chloride ion, if susp ected w ith Chlor*Rid ta i n s a m p l e G R e ta G
A i r co c o m p r e ss o r e q u ip ip m e n t G Com pressed air lines
il a n d w a t e r c on on t a m i n a n t s , A ST ST M D 4 28 28 5 G C h e c k f o r o il Blast nozzle pre ssure G Blast G Check pressure at blast nozzle with hyp oderm ic needle gauge
G
S u r f a ce ce p r e p a r a t i o n G D o n o t p r o c e e d w i t h s u r f a ce ce p r e p a r a t i o n i f t h e s u b s t r a t e s u r f a c e t em em p e r a t u r e i s le le s s t h a n
5 d e g r e e s F a b o v e t h e d e w p o in in t ll o w i n g p r i o r t o cl cl e a n in in g : G D e t e r m i n e t h e r u s t g r a d e b y o n e o f t h e f o ll G SSPC SSPC -VIS -VIS 1, 1, for for abr asive blas t clea clea nin g
SSPC-VIS S 3, 3, for for han d an d p ow er tool clean clean ing G SSPC-VI SSPC-VIS 4(I), 4(I), for for w ater jettin g G SSPC-VIS G C h e c k f o r c h l o r id id e i o n c o n t a m i n a n t i n w a s h w a t e r o r w a t e r u s e d i n w a t e r je je t t in in g , i f s u s p e c t e d
lor*Rid W test kit G Use Ch lor*Rid G P r e p a r a t i o n c o m p l i e s w i t h s p e c if if ic ic a t i on on m e t h o d ( i. i. e .,., N A C E N o . 2/ 2/ S SP SP C - SP SP 1 0, 0, N A C E
N o . 3/ 3 / SSP C -SP 6, e tc .) for chloride ion contam inant after clean clean ing w ith Chlor*Rid Chlor*Rid test kit G Ch eck for G Determ ine de gree of surface cleanliness cleanliness by one of the following following after cleaning: G SSPC-VIS SSPC-VIS 1, 1, for for abr asive b last clea clea nin g G SSPC-VI SSPC-VIS S 3, 3, for for han d an d p ow er tool clean clean ing
f o r w a t er jett je tt in g G N A C E N o . 7 / SSP C -VI S 4 (I) , fo
C-1
G
Surface Surface pr ofile ofile profile by N ACE RP 0287 0287 G Determ ine surface profile
G
E n v i r o n m e n t a l c o n d i t i o ns ns G A m b i e n t (a (a i r ) t e m p e r a t u r e
su r f a c e t e m p e r a t u r e G S u b s t r a t e su G R e la la t i v e h u m i d i t y G Dew point
velocity, if ap ap plicable G Wind velocity, G
C o a t i n g a p p l ic ic a t io io n G Coatin g mat erial comp lies lies with spe cifi cifications cations
tu r e r ’ s in in s t r u c t i o n s G M i x e d i n a c c o r d a n c e w i t h m a n u f a c tu G T y p e o f a p p l ic ic a t io io n m e t h o d u s e d
ic a t io io n p r o c e e d s G E n s u r e s t r i p e c o a t s a r e a p p l i e d b e f o r e o v e r a l l a p p l ic ic t io io n s G T e m p e r a t u r e a n d h u m i d i t y r e s t r ic G A i r a n d s u b s t r a t e t em em p e r a t u r e s a r e 50 50 d e g r e e s F o r g r e a te te r o r c o m p l ie ie s w i t h t h e
m a n u f a c t u r e r ’s ’s i n s t r u c t i o n s G S u r f ac ac e s a r e a m i n i m u m o f 5 d e g r e e s F a b o v e d e w p o in in t
la t i v e h u m i d i t y w i t h i n m a n u f a c tu tu r e r ’ s in in s t r u c t i o n s G R e la G Surfaces free free of m oisture, frost, frost, and ice
G
Curing G C o a t e d i t e m s a r e n o t m o v e d o r a l lo lo w e d f o o t t r a ff ff ic ic b e fo fo r e d r y
tu r e r ’ s i n st st r u c t i o n s f o r te te m p e r a t u r e a n d h u m i d i t y d u r i n g c u r i n g p e r i o d G C o m p l i e s w i t h m a n u f a c tu G
Post app lication lication inspection G Dry film th icknes icknes s by SSPC-PA2 SSPC-PA2
li d a y t e st st i n g b y N A C E R P 0 1 88 88 G H o li
C-2
Appendix D Reference Standards Cited in Guide American Society for Testing and Materials (ASTM) ASTM A 123
Zinc (Hot-Dip Galvanized) Coatings on Iron and Steel Productions
ASTM A 153
Zinc (Hot-Dip) Coatings on Iron and Steel Hardware
ASTM A 591
Steel Sheet, Electrolytic Zinc-Cated, Light Coating Weight [Mass] Applications
ASTM A 653
Steel Sheet Zinc-Coated (Galvanized or Zinc-Iron Alloy-Coated (Galvanized) by the HotDip Method
ASTM B 633
Electrodeposited Coatings of Zinc on Iron and Steel
ASTM B 695
Coatings of Zinc Mechanically Deposited on Iron and Steel
ASTM D 3359
Measuring Adhesion by Tape Test
ASTM D 4138
Field Measurement of Dry Film Thickness of Protective Coating Systems by Destructive Means
ASTM D 4285
Indicating Oil and Water in Compressed Air
ASTM D 4414
Measurement of Wet Film Thickness by Notch Gages
ASTM D 4417
Field Measurement of Surface Profile of Blast Blast Cleaned Steel
ASTM D 4541
Pull-Off Strength of Coatings Using Portable Adhesion Testers Testers
ASTM D 4940
Conductimetric Analysis of Water Soluble Ionic Contamination of Blasting Abrasives
ASTM D 5064
Conducting a Patch Test to Assess Coating Compatibility
ASTM D 5162
Discontinuity (Holidays) Testing of Nonconductive Protective Coating on Metallic Substrates
ASTM E 337
Measuring Humidity with a Psychrometer (the Measurement Measurement of Wet- and Dry -Bulb Temperatures)
ASTM E 832
Laboratory Filter Papers
American Welding Society (AWS) AWS C2.2
Recommended Practices for Metallizing with Aluminum and Zinc Zinc for Protection of Iron and Steel
D-1
NACE International (NACE)/Society of Protective Coatings (SSPC) NACE NACE RP RP 0188
Disconti Discontinuit nuity y (Holi (Holiday) day) Testing esting of of New New Protect Protective ive Coatings oatings on Conduct Conductive ive Substrat Substrates es
NACE NACE RP 0287 0287
Fiel Field d Measur Measurem ement ent of of Surfac Surface e Prof Profil ile e of Abr Abrasive asive Blast Blast Cl Cleaned eaned Steel Steel Sur Surfa faces ces Usi Using ng a Replica Tape
SSPC-AB1
Mineral and Slag Abrasives
SSPC-PA2
Measu easurremen ementt of Dry Paint Thickn ckness with Magne gnetic Gage ages
SSPC-SP1
Solvent Cleaning
SSPC-SP2
Hand Tool Cleaning
SSPC-SP3
Power Tool Cleaning
SSPC-SP8
Pickling
SSPC-SP15
Commercial Grade Power Tool Cleaning
SSPC-SP11
Power Tool Cleaning to Bare Metal
NACE No. 1/ SSPC-SP5
White Metal Blast Cleaning
NACE No. 2/ SSPC-SP10
Near-White Metal Blast Cleaning
NACE No. 3/ SSPC- SP6
Commercial Blast Cleaning
NACE No. 4/ SSPC-SP7
Brush-Off Blast Cleaning
NACE No.5/ SSPC-SP-12
Surface Preparation and Cleaning by High- and Ultrahigh-Pressure Water Jetting Prior to Coating
NACE No. 8/ SSPC-SP-14
Industrial Blast Cleaning
SSPC-VI C-VIS S1
Abra Abrasi sive ve Bla Blast st Clea Cleane ned d Ste Steel el (Sta (Stand ndar ard d Ref Referen erence ce Phot Photog ogra rap phs) hs)
SSPC-VI C-VIS S2
Eval Evalua uati ting ng Degre egree e of Rust Rustin ing g on Paint ainted ed Steel teel Surf Surfac aces es
SSPC SSPC-V -VIS IS 3
Powe Powerr- and and Hand Hand-T -Too ooll Clea Cleane ned d Stee Steell (Stan Standa dard rd Refe Referrence ence Phot Photog ogra raph phs) s)
NACE No. 7/ SSPC-VIS 4
Guide and Visual Reference Photographs for Steel Cleaned by Water Jetting
NACE-VIS 9/ SSPC-VIS 5
Guide and Reference Photographs for Steel Surfaces Prepared by Wet Abrasive Blast Cleaning
D-2
Appendix E Inspection Equipment Inspection Gauges, Instruments, and Kits:
•
A d h e s io io n t e s t er er ( El El co co m e t e r ), ), d e s tr tr u c t iv iv e t e s ti ti n g ( op op t io io n a l )
•
B l as ast n o z z le le a n a ly ly z er er g a u g e (o ( o p t io io n a l) l)
•
C al a l i b ra r a te te d sh sh im im s
•
C o n d u ct c t iv iv i ty t y m et e t er er
•
D r y f i l m t h ic ic k n es e s s g a ug ug e
•
P u ll ll - o f f
•
F i x eed d o r c on o n s ta t a n t p re r e s su su r e p r ob ob e
•
E n v i ro r o n m e n t a l m e te t e r fo f o r a m b ie i e n t a n d s u r f ac ac e te t e m p e r a tu tu r e , h u m i d i ty ty , an a n d d e w p o in in t
•
H o li li d a y d e te t e c t or o r ( o p t io io n a l) l) : •
L o w vo vo lt a g e
•
H ig ig h vo v o l ta g e
•
M ic i c r o m et e t er er an a n d r ep e p l ic ic a ta ta p e
•
N o z z le l e o ri r i f i ce ce g a u g e ( o p t io io n a l) l)
•
P it it g a u ge g e (o (o p ti t i o n al a l)
•
P r es es su su r e n ee e e d l e g a u g e (o (o p ti t i o n a l) l)
•
S l in in g p s yc y c hr h r om om e t er er
•
S w a b ch c h e ck c k s fo r l ea ea d a n d c hr h r om om a t e
•
T e st st k i ts ts , ch ch l or or i d e i o n s p e c if if ic ic (C (C h l o r *R *R id id I n t e r n a t i o n a l )
•
T h eerr m o m e te t e r w i th t h m a g n et et ic i c ba b a ck ck in in g
•
T o ok ok e g a u g e , d e s tr tr u c t iv iv e d r y f il i l m th t h i c k n es es s i n st st r u m e n t (o (o p t io io n a l )
•
W e t f i l m t h ic ic k n es e s s g a ug ug e
Inspection Tools:
•
F l a sh s h l i g ht ht
•
1 t o 11- 1 / 2 in in c h w i d e st s t if if f pu p u t ty t y k n i fe fe w i t h s ha h a r p e ne ne d e d g e
•
Kn i fe
•
L a t e x gl g lo v e s
•
P la l a st st ic ic bo b o ot o t ie ie s
•
M agn et
E-1
Appendix F Example of Inspection Daily Check Sheet 1 of 2
COATING DAILY INSPECTION REPORT
Project:
Date:
Feature:
Report By:
Contract No:
Paint Contractor:
SPECIFICATIONS
Tabulat Tabulation ion No: No: ______ ______
Coati Coating ng Cat Catego egorry: ____ _______ ____ _ Coat No.
Item Item to be Coated: Coated: _______ ___________ ________ ______ ______ ________ _______ ____ _
Tota Totall DFT DFT (min. (min.): ): ____ ______ __ mils mils
Material Manufacturer
Tab Tab Surf Surface ace Prep. Prep. Meth Method od:: ____ _______ _____ __
Product Name
DFT Range
Primer: Intermediate: Topcoat: Reading Time:
WEATHER
1. Substrate Temperature (degrees F): 2. Ambient (Dry Bulb) Temp. (degrees F): 3. Wet Bulb Temperature (degrees F): 4. Relative Humidity (percentage): 5. Dew Point Temperature (degrees F): 6. Item (1) minus (2) (in degrees F): 7. Wind (mph) and Direction: Comments: Surface Preparation Method Used:
SURFACE PREPARATION
Abrasives:
Manufacturer: ______________
Contami Contaminant nants s (ASTM (ASTM D 4940): 4940): Chlo Chlori ride de Spec Specif ific ic Ion: Ion: Compress ressor or Air:
Product Name: _____________
Class A, Type _____
Fines Fines __ yes yes / __ no; no; Oil Oil __ yes yes / __ __ no; pH ____; ____; Conduc Conductiv tivity_ ity_____ ______ __
Test Test Metho ethod d Use Used d ____ ______ ___ _____ ______ ____ ____ ____ ____ ____ ____ ___; _; Resu Result lts s ____ ______ ____ ____ ____ ___ _ Type: pe: ____ ______ ______ ______ ___
Surf Surfac ace e Prof Profil ile e (NA (NACE CE RP RP 0287 0287): ):
Clea Cleanl nlin ines ess: s:
SSPC-SP _____ / NACE No. ______
Passes sses ASTM D 428 4285: ___ ___ yes / ___ no
No. No. Meas Measur urem emen ents ts Tak Taken en ___ ____ ___; __; Aver Averag aged ed Meas Measur ured ed __ ______ ____ mils
Chlo Chlori ride de Spec Specif ific ic Ion: Ion:
Visu Visual al Sta Stand ndar ards ds (SSP (SSPC/ C/NA NACE CE): ):
_____ ____ CFM CFM
Test Test Metho ethod d Use Used d ___ _____ ____ ____ ____ ____ __ _; Resu Result lts s ____ ______ ____ ____ ____ ___ _
VIS VIS 1 __ __ ye yes / __ __ no; no; VIS VIS 2 __ yes yes / __ __ no; no; VIS VIS 4 (I) (I) __ yes yes / __ no
F-1 F- 1
2 of 2
COATING DAILY INSPECTION REPORT APPLICATION AND MATERIALS
Manufacturer
Product Name
Batch Number
Gal
C o lo r
Thinner Product
Gal/Oz %
Environmental Control: Heaters ___ yes / ___ no; Dehumidification ___ yes / ___ no, Unit Size Size _________ Material Mixing: Power Mixing Mixing Time _____ minutes; Induction Time ___ yes / ___ no, _____ minutes Stri Stripe pe Coat Coats s Appl Applie ied: d: ___ yes / ___ ___ no;
Meth Method od:: ___ ___ Bush Bush/R /Roll oller er ___ ___ Spra Spray y
Application Method: ___ Brush; ___ Roller; ___ Airless; ___ Conventional; ___ Plural; Plural; ___ Electrostatic Applied Within Recoat Window: Primer __ yes /__ no; Intermediate __ yes /__ /__ no; Topcoat __ yes /__ no Wet Film Thickness (WFT): Primer ______ mils; Intermediate ______ mils; Topcoat ______ mils Comments: TESTING OF HARDENED COATING
Dry Film Thickness (DFT) by SSPC-SP PA2: Area Inspected: ___ less than 300 ft2 ; ___ less than 1,000 ft2; ___ equal to or greater than 1,000 ft 2 Number of 5 Spot Measurement Groups Taken Within Above Inspected Area: _____ at _____ 100 ft 2 areas Average of 5 Spot Measurement Groups _______ mils; Conform to Specifications Specifications ___yes /___no Discontinuity (Holiday) Testing by NACE RP 0188 Tester Used:
_____ Low Voltage (Sponge)
Set at _______ _______ volts; olts; Comments:
F-2 F- 2
_____ High Voltage
Number Number of Defects Defects Found Found ______ _______; _; Defects Defects Repair Repaired ed ___ ___ yes yes / ___ ___ no no
Appendix G Procedure for Detecting Moisture and Oil in Co mpressed Air (ASTM D 4285) A. Purpose
T h i s t e s t d e t e c t s t h e p r e s e n c e o f m o is is t u r e a n d o il il c o n t a m i n a n t s i n c o m p r e s s e d a ir ir f o r a b r a s i v e bl b l a s t ing in g , a i r b la s t cl e a n i n g , a n d c o a t in g a p p l ica ic a t ion io n o p e r a t i o n s . Th e c o n t a m i n a n t s a r e d e t e ct e d visually. B. Equipment
W h i te te a b s o r b e n t m a t e r i al al , fi fi lt lt e r p a p e r , b l o tt tt e r p a p e r , o r c l ot ot h w i th th a r i g i d b a c k i n g . C. Procedure
1 . A l lo lo w t h e a i r co co m p r e ss ss o r t o r ea ea c h o p e r a t i ng n g c o n d i t io io n s . 2 . Sh u t o f f t h e a br b r a s i ve v e fl fl ow ow . 3 . P l a ce ce t h e a b s o r b e n t m a t e r ia ia l w i t h i n 2 4 i n c h e s o f t h e d i s c h a r g e - p o i n t -c -c e n t e r e d a i r s t r e a m a n d d o w n s t r e a m f r o m t h e i n -l -l in in e o i l a nd nd m o i s t u r e s e p a r a t o r s . 4 . A l l ow ow a i r to t o fl fl o w fo fo r 1 m i n u t e . 5 . V is is u a l l y ch ch e c k a b s o r b e n t m a t e r i a l f o r t h e p r e s e n c e o f m o i s t u r e o r o il il . A n y o b s e r v e d c o n t a m i n a n t s o n t h e c lo lo t h o r i n t h e a i r f lo lo w w i ll ll r e q u i r e c o rr rr e c t iv iv e a c t i o n . T e s ts ts s h o u l d b e p e r f o r m e d a t t h e b e g i n n i n g o f th th e s h i ft ft o r a f t e r th th e a i r co co m p r e s s o r h a s b e e n s h u t o f f. f. T e st st i n g i s r e c o m m e n d e v e r y 4 h o u r s d u r i n g b l a s t in in g o p e r a t i o n s o r m o r e f r e q u e n t ly ly i f h u m i d i t y i s high.
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Appendix H Procedure for Detecting Chlorides and Soluble So luble Salts in Abra Ab rasives sives by Conduct Con ductivit ivityy Method Met hod A . P u rp o s e
T o d e t e c t a n d d e t e r m i n e t h e l e v e l o f s o lu lu b l e s a l t s in in a b r a s i v e s t o p r e v e n t s u b s t r a t e d e t e r io io r a t i o n a n d s u b s e q u e n t c o a t i n g f a i lu lu r e . B.
C o n du d u ct ct i v it i ty M e t ho ho d
1 . E q ui u ip m e n t a . E le le c tr tr o n i c c o n d u c t iv iv i t y m e t e r 2 . P ro r o ce ce du du r e a . C a l ib ib r a t e t h e c o n d u c t iv iv i t y m e t e r a c c o rd rd i n g t o t h e m a n u f a c t ur ur e r ’s ’s in in s t ru ru c t io io n s . b . P la ce e q u a l v o lu m e s of a b r a s iv e m a t e r ia l a n d d is t ill e d o r d e -io n i z ed w a t e r in a g l a ss a n d s t ir ir f or or 1 m i n u t e . L et et s t a n d f o r 8 m i n u t e s a n d s t ir ir a g a i n f or or 1 m i n u t e . A l lo lo w t h e a b r a s iv iv e m aterial to settle. c . I n se se r t t h e c o n d u c ti ti v it it y m e t e r p r ob o b e i n t h e w a t e r w i th t h o u t co co n t a c ti ti n g a b r a s iv iv e m a t e r ia ia l. l. d . A l lo lo w t h e c o n d u c t i v it it y m e t e r t o st st a b i li li z e i n a cc cc o r d a n c e w i t h t h e m a n u f a c t u r e r ’s ’s instructions. e . R e a d a n d r e co co r d t h e d i r e ct ct r e ad a d i n g in i n m i cr c r o si s i e m e n s. s. C. Chloride-Specific Chloride-Specific Ion Ion M ethod
1 . P u rp r p os ose T o d e t e r m i n e t h e c o n c e n t r a t i o n o f ch ch l o r i de de s i n a b r a s i v e m a t e r i a ls ls a n d p r e v e n t s u b s t r a t e c o n t a m i n a t i o n a n d s u b s e q u e n t c o a t i n g f a i lu lu r e . 2 . E q u ip ip m e n t CH LOR*TE LOR*TEST ST A, Chloride Ion Test For Abra sives sives titration kit
H-1
3 . P ro r o ce ce du du r e a . O v e r f i ll ll t h e s m a l l c o n t a in in e r w i t h a b r a s iv iv e b l a s t m a t e r ia ia l a n d l e v e ll- o ff ff w i t h t h e m e t a l s n a p p e r i n c lu lu d e d w i t h t h e k i t o r w i t h a s t r a i g h t e d g e . b . Re m ov e t h e l id fr o m th e C H LO R*EX TRA TR A C T s o lu ti o n co n ta in er an d p ou r th e le v el e d -off -o ff b l a st a b r a s iv e m a t e r ia l i n t o t h e s o l u t io n . c . R e p l a c e t he he l id id o f t h e C H L O R *E *E XT XT R AC AC T s o l u t io io n c o n t a i n e r a n d v i g o r o u s l y s h a k e fo fo r 2 m i n u t e s . A l l o w t h e a b r a s i v e m a t e r i a l t o s e t tl tl e fo fo r a b o u t 5 m i n u t e s b e fo fo r e p r o c e e d i n g . C l e a r s o lu lu t i o n s h o u l d b e v i si si b le le a b o u t a ½ i n c h f r o m t h e t o p s u r f a c e. e. d . H o l d t h e t it it r a t io io n t u b e a lo lo n g t h e m i d d l e . D o n o t h a n d l e o r t o u c h t h e n a r r o w e n d s b e fo fo r e o r a f t e r s n a p p i n g t h e m o f f. f. H a n d l i n g o f t he he t i t ra ra t io io n t u b e n a r r o w e n d s c a n c o n t a m i n a t e t h e solution w ith bod ily ily persp iration, i.e., i.e., salts, and affect the results. Snap off both both end s of the t i tr tr a t i o n tu tu b e a n d h o l d t h e t u b e in in t h e so so l u t i o n w i t h th th e b lu lu e a r r o w h e a d p o i n ti ti n g u p . D o n o t i n s e r t t h e t i tr tr a t io io n t u b e i n t o t h e a b r a s i v e m a t e r i a l b e c a u s e t h i s m a y p l u g t h e t u b e . e . A l l ow ow t h e t it it r a t io io n t u b e t o r e m a i n i n th th e e x t r a c te te d s o l u t i o n u n t i l t h e s ol ol u t i o n h a s w i c k ed ed - u p t o t h e t o p o f t h e c o t t on on w i ck ck e t . S at at u r a t i o n o f t h e w i ck ck e t i s c o m p l et et e w h e n t h e co co t t o n t i p c h a n g e s t o a n a m b e r c o lo lo r . f . I m m e d i a t el ely a f t er er t h e c o t to to n t i p h a s c h a n g ed e d t o a n a m b e r c ol ol o r, r, r e m o v e t h e t it it r a ti ti o n t u b e f r o m t h e t e s t s le le e v e a n d r e a d t h e c h l o r i d e l e v e l a t t h e i n t e r f a ce ce o f t h e p i n k - w h i t e c o lo lo r chan ge. W hite ind ind icates icates the presen ce of chloride. chloride. If no color color chang e occur s (rem ains all p in k ), t h e ch lo r id e le ve l is be lo w th e th re sh ol d d et ec t io n lim li m i t of t he ti t ra ti on ki t . Th e c h l o r id id e c o n c e n t r a t i on on l e v e l is is r e a d d i r e c t ly ly f r o m t h e t i t r a t io io n t u b e i n m i cr cr o g r a m s p e r s q u a r e c e n t im im e t e r o r p p m .
H-2
Appendix I Procedures for Detecting Chloride Ion in Water A . P u rp o s e
T o d e t e r m i n e t h e c o n c e n t r a t io io n o f c h l o r id id e i o n s i n w a t e r u s e d w i t h w a t e r je je t t in in g b l a s t c le le a n i n g o r f o r w a t e r e v a l u a t i o n t o p r e v e n t s u b s t r a t e c o nt nt a m i n a t io io n a n d s u b s e q u e n t c o a t i n g f a i lu lu r e . B.
Eq ui u i pm p m en en t
CH LOR*TE LOR*TEST ST W , Chlorid e Ion Ion Test For Water/ Liqu Liqu ids titration titration k it C.
P ro ce ce d u re re
1 . R e m o v e d r o p p e r a s se se m b l y c ap a p f ro ro m b o t t le le . 2 . U s e t he h e d r o p p e r a s se s e m b l y i n th t h e b o t tl tl e t o t r an an s f er er t h e w a t er er t o b e t es es t e d . A d d a b o u t a ½ in in c h of water to the bottle. 3 . H o l d t h e t it it r a t io io n t u b e a lo lo n g t h e m i d d l e . D o n o t h a n d l e o r t o u c h th th e n a r r o w e n d s b e fo fo r e o r a f t e r s n a p p i n g t h e m o f f. f. H a n d l i n g o f t he he t i t ra ra t io io n t u b e n a r r o w e n d s c a n c o n t a m i n a t e t h e solution w ith bod ily ily persp iration (i.e.) (i.e.),, salts, and affect the results. Snap off both both end s of the t i t r a ti ti o n t u b e a n d h o l d t h e t u b e i n t h e s o lu lu t i o n w i t h t h e b lu lu e a r r o w h e a d p o i n t i n g u p . 4 . A l l ow ow t h e t i t r a t i on on t u b e t o r e m a i n i n t h e e x t r ac ac t e d s o l u t io io n u n t i l t h e so so l u t i o n h a s w i ck ck e d - u p t o t h e t o p o f c o t t o n w i c k e t . Sa t u r a t i o n o f t h e w i c k e t is is c o m p l e t e w h e n t h e c o t t o n t i p c h a n g e s t o a n a m b e r c o lo lo r . 5 . I m m e d i a t e l y a f t e r t h e c o t t on on t i p h a s c h a n g e d t o a n a m b e r c o lo lo r , r e m o v e t h e t i t r a t io io n t u b e f r o m t h e t e s t s le le e v e a n d r e a d t h e c h l o r id id e l e v e l a t t h e i n t e r f a ce ce o f t h e p i n k -w -w h i t e c o lo lo r c h a n g e . White ind icates icates the presen ce of chloride. If no color chang chang e occurs occurs (rem ains all pink), the chloride level is below below th e th reshold d etection etection limit of the titration titration kit. The ch ch loride c o n c e n t r a t i on on l e v e l i s re re a d d i r e c t ly ly f r o m t h e t i t r a t io io n t u b e i n m i cr cr o g r a m s p e r s q u a r e c e n t i m e t e r or ppm.
I-1
Appendix J Procedures for Determining Blast Cleaning Air A ir Pressure A . P u rp o s e
To me asure th e blast hose air pressur e for assessing assessing ab rasive blast clean clean ing effici efficiency. ency. B.
Eq ui u i pm p m en en t
H y p o d e r m i c n e e d l e p r e s s u r e g a u g e , 0 t o 12 12 0 p o u n d s p e r s q u a r e i n c h ( p s i ) o r m o r e . C . P ro ce ce d ur u re
1 . Bl a s t c le le a n i n g e q u i p m e n t i s t o b e o p e r a t i o n a l a t th th e t im im e o f te te s t in in g . I f m o r e t h a n o n e b l a s t h o s e is to be used , operate all blast hoses. 2 . I n se se r t h y p o d e r m i c n e e d l e p r e s su su r e g a u g e in in t o t h e in in t e r i o r of of t h e b l as as t h o s e i m m e d i a t e ly ly i n f r o n t o f t he he b l a s t n o z z l e a n d s la la n t t h e n e e d l e a t a 4 5 d e g r e e a n g l e s o t h a t i t is is p o i n t e d i n t h e d i r e c t io io n t h e a b r a s i v e s a r e f lo lo w i n g t o m i n i m i z e n e e d l e c lo lo g g i n g a n d d a m a g e . 3 . R e a d t h e b l as as t cl cl e a n i n g ai ai r p r e s s u r e d i r e ct ct l y fr fr o m t h e d i al al g a u g e . N o r m a l b l as as t p r e s s u r e is is b et w ee n 90 an d 100 10 0 p si. si . 4 . P r e s s u r e r e a d i n g s s h o u l d b e t a k e n p e r i o d i ca ca l l y o r w h e n b l a s t c le le a n i n g e f fi fi ci ci e n cy cy d e c r e as as e s . N O TE : 1 . U s e th th i s t es es t m e t h o d o n l y fo fo r ab ab r a s i v e b l a s t h o s e s . D o n o t u s e th th i s m e t h o d o n c oa oa t i n g a p p l ic ic a t i on on h o s e s . 2 . T h e r e is is n o cu cu r r e n t s t a n d a r d r e f e r e n ce ce t o d e t e r m i n e b l a s t p r e s s u r e ; A S TM TM D 4 2 64 64 w a s withdrawn.
J-1
Appendix K Determination of Environmental Factors E n v i r o n m e n t a l fa fa c t o r s a r e d e t e r m i n e d b y v a r i o u s i n st st r u m e n t s , a n d s o m e i n s t r u m e n t s ca ca n p e r f o rm rm m u l t i p l e fu fu n c t i o n s . E l ec ect r o n i c a n d d i g i t a l in in s t r u m e n t s a r e b e c o m i n g i n c r e a s in in g l y m o r e a c c u r a t e , f as as t e r , m o r e a f fo fo r d a b l e , a n d a cc cc e p t a b l e . T h e i n s t r u m e n t s a r e n o t d e t a i le le d b e l o w b e ca ca u s e of of w i d e v a r i a t io io n a m o n g i n s tr tr u m e n t t y p e s a n d b e c a u s e o f t h e va va r i a t i on on i n t h e w a y i ns ns t r u m e n t s a r e u s e d . Bu t , a s w i t h a n y i n s t r u m e n t , a lw lw a y s f o ll ll o w t h e m a n u f a c tu tu r e r ’ s in in s t r u c t i o n s. s. T h e f o ll ll o w i n g s e c t io io n s d e s cr cr i b e th th e i n s t r u m e n t a n d t h e p r o c e d u r e s t o b e u s e d t o d e t e r m i n e e a c h e n v i r o n m e n t a l fa fa c t o r : A.
A m b i e n t Te T e m p e ra ra t ur u re b y T h e rm rm o m e t er er
1 . D e s cr cr i pt p t i o n o f t h e P r oc oc e d u r e a . D e t e r m in in i n g t h e a m b i e n t te te m p e r a t u r e b y a s in i n g l e d i re r e ct ct r e a d i ng n g w i t h a t h e rm rm o m e t e r. r. 2 . E q u ip ip m e n t a . A t h e r m o m e t er e r o r t h e d r y b u l b t h e rm r m o m e t e r o f a p s y ch ch r o m e t er er . 3 . P ro r o ce ce du du r e a . A m b i en en t t e m p e r a tu tu r e s h o u l d b e t a k e n n e a r th t h e s u r f ac ac e to to b e co co a t e d . L oc oc a te te a ll ll t h e r m o m e t e r s a n d i n s t r u m e n t s w h e r e t h e y a r e n o t s u b j ec ec t to to d i r e c t su su n l i g h t , w i n d , c o n s t r u c t io io n l i g h t i n g , h e a t in in g o r v e n t i l a t io io n d u c t s , a nd nd w h e r e t h e y a r e n o t s u b je je c t t o o t h e r c o n d i t i on on s t h a t w o u l d a f fe fe c t t ru ru e t e m p e r a t u r e r e a d i n g s . b . L et te m p e r a t u r e e q u i p m e n t st a b ili z e fo r 1 t o 2 m in u t e s if i f i t w a s b r o u g h t fr o m a p l a ce w h e r e t h e t e m p e r a t u r e w a s d i f fe fe r e n t fr fr o m t h e a r e a w h e r e t h e e q u i p m e n t w i ll ll be be u s e d ( e .g .g . , a n a ir ir c o n d i t io io n e d o r h e a t e d r o o m o r n e x t t o s om om e o n e 's 's b o d y ) . c . A l l i n s tr tr u m e n t s a r e d i r e c t r e a d . F o r e l e c tr tr o n i c i n s tr tr u m e n t s , fo l lo lo w i n s t r u c t io io n s a n d e n s u r e t h a t t h e c o r r e c t m o d e i s b e in in g u s e d a n d t h e r e a d i n g i s o n t h e d e s i r e d s c a l e, e, d e g r e e s F o r Celsius. B.
S u b s t ra ra te te S u rf ac ac e T e m p e ra ra tu tu re re
1 . D es e s ccrr ip ip t io io n a . D e t er er m i n i n g t h e s u r f ac a ce t e m p e r a t u r e o f t h e s ub ub s t r a t e to t o b e co co a t e d 2 . E q u ip ip m e n t a . D ia ia l th t h e rm r m o m e t er er w i th t h a m a g n et e t ic i c ba b a ssee
K-1
3 . P ro r o ce ce du du r e a . P l a ce ce t h e d i al al t h e r m o m e t e r o n t h e s t e e l s u b s tr tr a t e a n d a l lo lo w t h e t e m p e r a t u r e t o s t a b il il iz iz e f o r about 2 to 3 minu tes. C.
R e la la ttii v e H u m i d i ty ty a n d D e w P o i n t (A (A S T M E 33 33 7 )
1 . D es e s ccrr ip ip t io io n a . D e t er er m i n in in g r e l a ti ti v e h u m i d i ty t y a n d d e w p o i n t t o a s ce ce r ta ta i n i f e va va p o r a t i on on w i l l oc o c cu cu r . T he he s u b s t r a t e s u r f a c e is is t o b e a t l e a s t 5 d e g r e e s F a b o v e t h e d e w p o i n t . 2 . E q u ip ip m e n t a . P sy sy c h r o m e t e r, r, e i th th e r s l in in g o r b a tt tt e r y , a n d p s yc y c h r om o m e t ri ri c t a bl bl e a n d c h ar ar t s . b . Ele El e ct r on ic or d ig it a l m et er (p r ov id es d ir ec t r ea d in g s). s) . 3 . P r oc oc e d u r e f or o r P s yc y c h ro ro m e t e r a . T h e w i ck ck o f a w e t b u l b p s y c h ro ro m e t e r (c (c ot ot t o n s o ck ck ) sh sh o u l d b e r e l a t iv iv e l y cl cl ea ea n . D ir ir t y w i ck ck s n e e d t o b e c le le a n e d o r r e p l a c e d . b . Sa t u r a t e t h e w i ck o n t h e w e t b u l b , b u t k e e p t h e d r y b u lb t h e r m o m e t er d r y . c . W h i r l (s (s l in in g t y p e ) o r o p e r a t e f a n ( b a t t e ry ry t y p e ) u n t i l t h e t h e r m o m e t e r s s t a b i l iz iz e , a b ou ou t 2 0 t o 3 0 s e co co n d s , a n d n o t e t h e t e m p e r a t u r e . d . R e p e a t s te te p s 2 a n d 3 w i t h o u t r e -w -w e t t in in g t h e w i c k u n t il i l t w o o r m o r e w e t b u l b r e a d i ng ng s a r e equal to the lowest temp erature obtained. e . R e co co r d t h e d r y ( a ir ir ) a n d w e t b u l b te t e m p e r a t u r es es . f . T h e r el e l at a t iv iv e h u m i d it i t y is is d e t e rm r m i ne n e d f ro ro m t h e i n t e r se se ct ct o f t h e d r y a n d w e t b u l b r e a d i n gs gs o n p s y c h r o m e t r i c t a b l e s o r c h a r t s . Ps y c h r om e t r i c t a b l e s a n d c h a r t s n o r m a l ly a r e i n c lu d e d w i t h the instrument. 4 . D ew e w P oi oi n t a . U s i ng ng t h e p s yc y c h r om o m e t ri ri c t a bl bl e s: s: ( 1) 1) D e t e r m i n e t h e a t m o s p h e r i c (b (b a r o m e t r ic ic ) p r e s s u r e f o r y o u r g e o g r a p h i c a l lo lo c a t io io n f r o m U . S. S. De De p a r t m e n t o f C om om m e r c e o r U . S. S. W ea ea t h e r B u r e a u t a b l es es . T h e a v e r a g e b a r o m e t r i c p r es su r e a t s ea le v el is ab ou t 3 0 i n ch es of m er cu r y , a n d it w il l a v er a g e l e ss th a n 30 inches at higher elevations.
K-2
( 2) 2) D e t er er m i n e t h e d i f fe fe r en en c e b et et w e e n t h e d r y a n d w e t b u l b te te m p e r a tu tu r es es . T h e w e t b u l b t e m p e r a t u r e i s a lw lw a y s l e ss ss t h a n t h e d r y b u l b . T h e d i f fe fe r e n c e i s c o m m o n l y c a ll lle d t h e “ d e p r e ss ss i o n o f th th e w e t b u l b . ” ( 3) 3) F r om om t h e t a b l es es , lo lo ca ca t e y o u r g e o g r a p h i c a t m o s p h e r i c p r e s su su r e (l (l o c a te te d i n t a b l e h e a d e r ) , d r y b u l b t e m p e r a t u r e ( r o w h e a d e r ) , a n d d e p r e s s i o n o f w e t b u l b (c (c o lu lu m n h e a d e r ) a n d d e t e r m i n e t h e c o r r e s p o n d i n g d e w p o i n t va va l u e . D e w p o i n t is is g i v en en i n d e g r e e s F a h r e n h e i t o r C e l s iu iu s . D . Wind
1 . D es e s ccrr ip ip t io io n a . D e te te r m i n i n g w h e n t h e w i n d v e l oc oc it it y c an an c a u s e i n d r y s p r a y , ov ov e r s p r a y , o r d a m a g e to to n e a r b y e q u i p m e n t , m e t a lw lw o r k , o r p r o p e r t y . 2 . E q u ip ip m e n t a . R o ta ta t i n g v a n e a n e m o m e t e r s , d i r ec ec t d i a l, l, o r e le le c tr tr o n i c (d (d i g i t a l) l) 3 . P ro r o ce ce du du r e a . P la la c e or or h o l d t h e i n st st r u m e n t in in t h e d i r e ct ct io io n o f th th e w i n d a n d r e a d t h e w i n d ( a ir ir ) v e lo lo ci cit y . D i g i t a l a n e m o m e t e r s m a y r e q u i r e h o l d i n g d o w n a s w i t c h o r b u t t o n f or or a fi fi x e d p e r i o d o f t i m e t o d e t e r m i n e t h e a v e r a g e a i r v el el o c i ty ty . F o l lo lo w t h e m a n u f a c t u r e r ’s ’s i n s t ru ru c t io io n s .
K-3
Appendix L Procedures for Detecting Chloride Salts on Prepared or Existing Surfaces A . P u rp o s e
T o d e t e c t c h l o r i d e i o n s a n d t h e i r c o n c e n t r a t io io n l e v e l o n p r e p a r e d s u r f a c e s o r e x is is t in in g s u r f a ce ce s f o r p r e c o a t in g e v a l u a t i o n t o p r e v e n t s u b s t r a t e co n t a m i n a t io n a n d s u b s e q u e n t c o a t in g fa i lu r e . B.
Eq ui u i pm p m e nt nt
CHLOR*TEST titration kit C.
P ro ce ce d u re re
1.
T e st st a s p o t w h e r e t h e s u r fa f a ce ce i s r e la la t iv iv e ly ly s m o o t h . D o n o t p i ck ck i rr rr e g u l a r s ur u r f a ce ce s su su c h a s c o r r o s io io n p i t s a n d w e l d s p a t t e r , a n d d o n o t p i ck ck a r e a s b e t w e e n d e p r e s s e d a n d r a i s e d su su r f a c e s be c a u se t h e se s u r f a c e s m a y a l l o w t h e so l u t i o n t o l e a k o u t .
2.
P o u r t h e e n t ir ir e c o nt nt e n ts t s f r om o m t h e s o l ut u t i o n bo bo t t le l e in in t o t h e t e st st sl sl e ev ev e .
3.
P e a l o ff f f t he h e b lu lu e b a c k in in g f r o m t h e a d h e s iv iv e s t r ip ip o n t h e o p e n e n d o f t h e t es e s t sl sle e v e a n d d i s ca ca r d t h e b a c k in in g . R e m o v e a i r fr fr o m t h e t e s t s le le e v e b y s q u e e z i n g b e t w e e n f in in g e r s a n d thu m b. Do not spill any of the solution. If solution is lost, d iscard iscard the test sleeve and t he r e m a i n i ng ng s o l u ti t i o n a n d b e ga ga n w i t h a n e w k i t .
4.
A p p l y th th e a d h e s iv iv e s tr tr i p o f t h e t e s t s le le e v e t o t h e t es es t s u r fa fa ce ce a n d f ir ir m l y p r e s s t h e a d h e s i v e s t r i p t o en en s u r e a p r o p e r s e a l . F o r a p p l y in in g t h e a d h e s i v e s t r ip ip t o h o r i z o n t a l s u r f a ce ce s , a l lo lo w t h e s o l u t io io n t o f i l l t h e c l o s ed ed e n d o f t h e t e s t s le le e v e a n d s q u e e z e t h e t e s t s l e ev ev e i n t h e m i d d l e w i t h i n d e x a n d m i d d l e fi fi n g e r s t o p r e v e n t s o l u t i o n l os os s .
5.
M a s s a g e t h e s ol ol u t io io n a g a i n st st t h e t es es t s u r fa fa ce ce f or o r 2 m i n u t e s. s . A l l t h e so s o lu lu t io io n s h o u l d b e e x p o s e d t o t h e t e s t s u r f ac ac e d u r i n g m a s s a g i n g t o e x t r a c t a n y c h l or or i d e s a l t s . T h e fo fo l l ow ow i n g p r oc ed u r es ar e r ec o m m en d ed for fo r th e v a r io u s t es t s u r fa ce p os it io n s, so th a t t h e s ol u ti o n w il l f lo lo w t o w a r d s t h e t e s t s u r f a ce ce w i t h ou ou t s o l u t i on on l o s s. s. a.
H o r i z o n t al a l a n d v e r t ic i ca l - L if if t th th e c lo l o s ed ed e n d o f t h e te t e s t sl s le e v e u p , a l lo lo w i n g t h e s o l ut ut i o n t o f lo lo w t o w a r d s t h e t e s t s u r f a c e. e.
b .
O v e r h e a d - L ift t h e clo s e d e n d o f t h e t es t s le e v e u p , a llo ll o w in g t h e s o lu t io n t o flo w t o w a r d s t h e m i d d l e o f t h e t e st st s l e e ve ve . Th e n s q u e e z e t h e e m p t y p o r t i o n o f t h e t es es t s le le e v e w i t h t h e i n d e x a n d m i d d l e fi fi n g e r s a n d s li li d e t h e f in in g e r s a l o n g t h e t e s t s le le e v e , fo fo r c in in g t h e s o l u t i o n to the test surface.
L-1
I f th th e s o l u t i o n i s l e a k in in g o u t f r o m t h e t e s t s l ee ee v e , d i s ca ca r d t h e t e s t s l ee ee v e a n d t h e r e m a i n i n g s o l u t io io n a n d b e g i n w i t h a n e w k i t . 6.
A f t e r m a s s ag ag i n g th t h e s o l u t i on on f or or 2 m i n u t e s , r e m o v e t h e t es es t sl s l e ev ev e a n d s ol ol u t i on on f ro r o m t h e t es es t surface. To rem ove the test sleeve and retain the solu solu tion from from the test su rface, rface, the follow follow ing p ro c ed u r e s ar e re co m m e n d e d f or t h e v a r i ou s t es t su r fa c e p o si ti o n s: a.
V e rt r t i ca ca l a nd nd o v er er h e a d - Lo Lo w e r t h e t e st s t s le le e ve v e , a ll llo w i n g t h e s ol o l u ti ti o n t o fl f lo w t o w a r d t h e closed end of the test sleeve. sleeve.
b .
H o r i z o n t a l - W i th t h e t e s t sl e ev e l a y i n g f la t , s q u e e z e t h e s o l u t i o n t o w a r d s t h e c lo s e d e n d of th e test sleeve. Then , pinch off an d lift u p th e test sleeve near th e test su rface, rface, allow allow ing t h e s o l u t i o n t o f lo lo w t o w a r d s t h e c l os os e d e n d o f t h e t e s t s le le e v e .
7.
P u n c h o u t t h e p e r fo fo r a te te d h o le le o n t h e l id id o f t h e o r i g in in a l b ox ox c on on t a i n e r li l i d , cl cl os os e t h e b ox ox l id id , a n d i n s e r t t h e t e s t sl sl e e ve ve w i t h t h e s o l u t i on on i n t o t h e h o l e .
8.
H o l d t h e ti t i tr tr a t io io n t u b e al a l on o n g th th e m i d d l e. e . D o n o t h a n d l e o r t o u c h t h e n a r ro r o w e n d s b ef e fo r e or or a f t e r s n a p p i n g t h e m o f f. f. H a n d l i n g t h e t i t r a ti ti o n tu tu b e n a r r o w e n d s c a n c o n t a m i n a t e t h e solution w ith bod ily p ersp iration (i.e.) (i.e.),, salts, and affect affect the results. Snap off both end s of the t i t r a ti ti o n t u b e a n d h o l d t h e t u b e i n t h e s o lu lu t i o n w i t h t h e b lu lu e a r r o w h e a d p o i n t i n g u p .
9.
A l lo lo w t h e t i tr tr a t io io n t u b e t o r e m a i n i n th th e e x t r ac a c te te d s o lu lu t io i o n u n t il il t h e s o lu lu t io io n h a s w i ck ck e d - u p t o t h e t o p o f c o t t o n w i c k e t . Sa t u r a t i o n o f t h e w i c k e t i s c o m p l e te te w h e n t h e c o t t o n t i p c h a n g e s t o a n a m b e r c o lo lo r .
1 0. 0. I m m e d i a te t e ly ly a f t er er t h e c o t to to n t i p h a s c h a n g ed ed t o a n a m b e r c ol ol o r, r, r e m o v e t h e ti t i t r at at i on on t u b e f r o m t h e t e s t s le le e v e a n d r e a d t h e c h l o r id id e l e v e l a t t h e i n t e r f a ce ce o f t h e p i n k -w -w h i t e co co l o r ch ch a n g e . White ind icates the p resence of chloride. If no color chang chang e occu occu rs (remains all pink), the chloride level is below below th e threshold d etection etection limit of the titration titration kit. The ch ch loride c o n c e n t r a t io io n l e v e l i s r ea ea d d i r e c t ly ly f r o m t h e t i t r a ti ti o n t u b e i n m i cr cr o g r a m s p e r s q u a r e c e n t im im e t e r o r p p m . 1 1. 1. A f t e r co co m p l e t in in g t h e t e s t , c le le a n t h e t e s t s u r f a c e (s (s u b s t r a t e ) w i t h a c e to to n e o r a l c o h o l t o r e m o v e a l l a d h e s i v e s t r ip ip r e s id id u e . N O T E : T h e p r e s e n c e o f s o m e s a lt io n s a n d c er t a in p H r a n g e s ca n a d v e r s e ly a f fe ct t h e a b o v e chloride test results in in the follow follow ing w ays: •
T h e p r e s e n ce c e o f b r o m i d e , io d i d e , or o r cy cy a n i d e io i o n s c a n yi yi e ld ld a h i g h e r c o n ce c e n t ra r a t i o n l e v el el t h a n t h e a c t u a l c h l o r i d e i o n s e x t r a c te te d f r o m t h e t e s t s u r f a c e .
•
T he he p r e s en en c e o f su su lp lp h i d e i on o n s ca ca n t u r n t h e c ot ot to t o n w i ck c k i n th th e t i tr t r at a t io i o n t u b e a b r ow ow n i sh sh c o lo lo r r a t h e r t h a n w h i te te a n d c an an y i el el d a h i g h e r c on on c en en t r a t io io n l e v e l t h a n t h e a c t u a l c h l or or i d e i o n s e x t r a ct ct e d f r om om t h e t e s t s u r f a c e .
•
p H v a l u e s o f l es e s s t h a n 3 .5 .5 a nd n d h i g h e r t ha h a n 1 1 c a n y i e ld ld a h i g h e r co c o n c e n t r a ti ti on o n l ev ev e l t h a n t h e a c t u a l ch l o r i d e i o n s e x t r a c t e d f r o m t h e t e s t s u r f a c e .
L-2
Appendix M Determining Surface Profile of Blast-Cleaned Steel Using Replica Tape (NACE RP0287 or ASTM D 4417, Method C) A . D e sc s c ri p ptt i on on
T o d e t e r m i n e t h e a n c h o r p a t t e r n d e p t h o f a b r a si si v e b l a s t ed ed s u r f a ce ce s b y u s e o f a s p r i n g m i cr cr o m e t e r a n d r e p l i c a im im p r e s s i o n t a p e . B.
C.
Eq ui u i pm p m en en t
1.
S p ri r i ng ng m i cr cr om om e te te r
2.
R e p l ic ic a i m p r e ss s s i on on t a p e , co a r se s e or or e xt x t r a c o ar ar s e
P ro ce ce d u re re
1.
M e a s u r e m e n t s a r e t o be be t a k e n o n a s m o o t h , f la la t o r c u r v e d p l a t e t h at a t i s fr fr e e of of s u r fa f a c e di di r t, t, d u s t , a n d a b r a s i v e p a r t i c le le s t h a t w i l l d i s t o r t r e s u l t s . A n a c c u r a t e p r o f i le le c a n n o t b e m a d e o n p it t e d or p ar ti a l ly co a te d a re as .
2.
Se l e ct ct t h e co c o r r e ct c t r e p l ic ic a t a p e r an an g e f o r t h e s p e ci c if ie ie d p r o fi f il e d ep ep t h a.
0 to t o 2 m i ls ls , u s e c o oaa rs rs e
b .
1.5 t o 4.5 m i ls, u se e x tr a c oa rs e
The replica tape ha s a thickness of 2 m ils ils but w ill vary s lightly. 3.
P r e p a r e th th e s p r i n g m i cr c r o m e t e r b y cl cl e an a n i n g th th e a n v i ls l s , se t t in in g t h e g a u g e t o z e r o, o , an an d c a li li b r a ti ti n g w i t h a s h i m b e t w e e n 1 a n d 4 m i ls ls . T h e sp sp r i n g m i cr cr o m e t e r sh sh o u l d b e p r e c is is e t o 0. 0. 3 mil.
4.
R e m o v e a si si n g le l e p i ec ec e of of r ep ep l ic ic a i m p r e ss s s io io n t a p e fr f r o m c on on t a i n er e r a n d p u l l o ff ff t h e a d h e s iv iv e ba c ki ng . Th e r e le a se p ap e r (n on ad h es iv e p ie ce ) w it h t h e ci rc le ca n be d is ca rd ed . Th e m e a s u r i n g p a p e r s t r i p h a s a 0 .4 .4 in in c h s q u a r e w h i t e p l a s ti ti c fi fi lm lm a t t h e c e n t e r o f t h e a d h e s i v e b a ck .
5.
Be fo fo r e a p p l y i ng ng t h e f il il m t o t h e b l a s te te d s u r f a ce c e , t h e t h i ck ck n e s s o f t h e f il il m m u s t b e s u b t r a c te te d f r o m t h e f i n a l r e a d i n g . Su b t r a c t i o n o f t h e f il il m t h i c k n e s s c an an b e a c c o m p l is is h e d b y o n e o f t h e f o ll ll o w i n g m e t h o d s :
M-1
a.
M e a s ur u r e t he h e r e p l ic ic a ta ta p e w i t h t he h e s p r i n g m ic i c r om o m e te te r a t t he h e r o u n d c u to t o u t p o rt r t i on on o p p o s it it e t h e 0. 4 in in c h s q u a r e w h i t e p l a s t ic ic f il il m a n d s u b t r a c t t h e r e p l i ca ca f i lm lm t h i ck ck n e s s b y o n e t h e f o l lo lo w i n g m e t h o d s : ( 1) 1)
Su b t r a c t th th e t h i ck ck n e s s fr fr o m t h e fi n a l r e a d i n g .
( 2) 2)
T u r n t h e d i a l in in d i ca ca t o r a r m o n t h e s p r i n g m i c ro r o m e t e r co c o u n t e r c lo lo ck ck w i s e fr fr o m z e r o the m easu red rep lica lica film film thickness (e.g., (e.g., for a me asure d 2.2 2.2 mils film film thickness, set the d ial ind icator icator arm at 7.8) 7.8).. This m ethod comp ensates for th th e rep lica lica film film t h i c k n e s s a n d p r o v i d e s a d i r e c t r ea ea d i n g .
b .
N om in a l t h ic k n es s o f t h e r ep li ca t a p e i s 2 m il s. In st ea d of m ea su r in g th e r ep li ca t a p e, it is accep accep table pra ctice ctice to use the 2 m il nom inal thickness an d su btract the rep lica lica film film t h i ck ck n e s s b y o n e t h e fo l lo lo w i n g : ( 1) 1)
Su b t r a c t th th e t h i ck ck n e s s fr fr o m t h e f in in a l r e a d i n g .
( 2) 2)
S et et t h e d i a l i n d i ca ca t o r a r m a t 8 .0 .0 (t (t u r n i n g i t c o u n t e r c lo lo c k w i s e fr fr o m z e r o ) o n t h e s p r i n g m i cr cr o m e t e r t o p r o v i d e a d i r e ct ct r e a d i n g .
6.
A p p l y t he h e fi fi lm lm t o t h e b la la s t ed e d s u r f a ce ce . T h e a d h e s i v e ba ba c k in i n g w i ll l l h o ld ld t h e fi fi lm lm i n p l a ce ce .
7.
W i t h a r o u n d e d t o o l (a b ar a r p l a st s t ic ic s w i zz z z le le s ti t i c k ha ha s b e e n fo fo u n d t o w o r k w e l l) l) , r u b o v e r t h e r o u n d c u t o u t p o r t i o n o f t h e r e p l i c a t a p e w i t h m o d e r a t e p r e s s u r e . T he he c ir ir c u l a r a r ea ea o f th th e r e p l i ca ca t a p e w i ll ll b e c o m e d a r k e r o r g r a y i sh sh , in in d i ca ca t i n g t h e b l a st st e d p r o f i le le h a s b e e n r e p l ic ic a te te d . E n s u r e t h e e n t i r e c ir ir c u l a r a r e a h a s u n i f o r m l y d a r k e n e d .
8.
R e m o v e t he he r e p l ic ic a ta ta p e a n d p l a ce ce i t b e tw tw e e n t h e a n v i ls ls o f t h e s p r i ng n g m i cr cr o m e t e r ( w i t h c ir ir c u l a r a r e a c e n t e r e d b e t w e e n t h e a n v i l s ). ). G e n t l y r e l e a s e t h e t r i g g e r o f t h e m i c r o m e t e r a n d t a k e r e a d i n g . D e p e n d i n g o n t h e g a u g e s e t t in in g , e it it h e r z e r o o r t h e m e a s u r e d r e p l i ca ca t a p e t h i ck ck n e s s , e n s u r e o r ig i n a l r e p l i ca ca t a p e t h i c k n e s s i s s u b t r a c t e d f r o m r e a d i n g .
9.
T h r e e r ea ea d i n g s sh sh o u l d t a k e n in in o n e lo l o c at a t io io n w i t h i n a b o u t 3 in in c h e s o f e a ch ch o t h e r a nd nd a v e r a g e d . L o ca ca t i o n r e a d i n g s ( t h r e e a v e r a g e d r e a d i n g s ) s h o u l d b e t a k e n o n e v e r y 1 0 0 s q u a r e feet of surface, or p ortion thereof, to establish consistency of the prof ile.
1 0. 0. R e t ai a in r e p l i ca c a t e d t ap a p e s a m p l e s fo fo r f u t u r e r e f er e r e n ce ce .
M-2
Appendix N Procedures for Measuring Wet Film Thickness (ASTM D 4414) A . P u rp o s e
T o d e t e r m i n e t h e w e t c o a t i n g t h i ck ck n e s s b e i n g a p p l ie ie d a n d t o e s ti ti m a t e t h e d r y f il il m t h i c k n e s s. s. B.
Eq ui u i pm p m e nt nt
A n o t c h g a u g e i s a r e ct ct a n g u l a r o r s qu qu a r e - s h a p e d p l a t e . E a ch ch e d g e h a s t w o o u t e r p r o je je c t io io n s o f e q u a l h e i g h t . B et et w e e n t h e o u t e r p r o je je ct ct i on on s i s a s e r ie ie s o f gr gr a d u a t e d n o t c h e s m a r k e d i n m i l s. s. E ac ac h ed ge of the notch gau ge is calibrated calibrated for a specific specific m il thickness range . Typical notch gau ge m aterials are are alu m inu m , plastic, plastic, p olish olish ed steel, and and stainless steel. N O TE : Th e p la st ic ga u ge s ar e d is p o sa b le an d ar e i nt en d ed fo r a li m it e d n u m be r o f re a d in g s. Th e a l u m i n u m a n d p l a s ti ti c g au au g e s w i l l w ea e a r d o w n a n d b e c om om e i n a c cu cu r a t e w i th th e x t e nd nd e d u s e . C.
P ro ce ce d u re re
1.
I f p o s s i b le le , t e s t a f la la t a r ea ea . F o r c ur ur v e d s u r f a c e s , t e s t al al o n g th th e l o n g i t u d i n a l ax ax is is , n o t t h e c u r v e d a x is is . T e st st s m o o t h a r e a s t h a t a r e f r e e f ro ro m s u r f a c e ir ir r e g u l a r i t ie ie s s u c h a s s e a m s o r welds.
2.
S e le le c t th th e m i l t h i ck ck n e s s ra r a n g e a l o n g t h e e d g e o f t h e g a u g e f o r th th e a n t i ci ci p a t ed ed f il il m t h i ck ck n e s s. s.
3.
T e st st im i m m e d i a t el el y a ft ft e r th t h e c oa o a t in in g i s ap a p p l ie ie d .
4.
F ir ir m l y p r e s s t h e g a u g e i n t o t h e w e t c o a ti t i n g , h o l d in in g t h e g a u g e p e r p e n d i cu cu l a r t o t h e s u b s t r at at e w i t h t h e t w o e q u a l o u t e r p r o je je c t io io n s r e s t in in g o n t h e s u b s t r a t e . D o n o t t i lt lt o r s cr cr a p e t h e g a u g e t h r o u g h t h e w e t c o a t in in g .
5.
R em e m o v e t he h e g a u g e f ro ro m t h e w e t c o at a t in in g a n d n o t e th t h e sh s h o r te t e sstt c oa o a t ed ed s te t e p b e tw tw e e n t h e n o t c h e s . T he he w e t f il ilm t h i ck ck n e s s l i e s b e t w e e n t h i s va va l v e a n d t h e a d ja c e n t u n c o a t e d s t e p .
6.
C le l e an a n t h e g a u g e be b e fo f o re r e ta t a k i ng n g th t h e n ex e x t m e a su su r e m e n t .
N-1
Appendix O Wet Film Thickness Formulas and Example Calculations A . D e sc s c ri p ptt i on on
D e t e r m i n i n g t h e w e t f i lm lm t h i c k ne ne s s ( W F T ) to to a c h i e v e a d e s i re re d d r y f il il m t h i c k ne ne s s ( D F T) T) B.
Fo rrm m u la la s
W ithou ithou t T hinning t he Coating Coating M ateria aterial l
N o t e :
P e r ce n t o f s o lid s b y v o lu m e is ex p r e s se d i n d e cim ci m a l f o r m .
Example:
T h e d e s i r ed ed D F T is is 8 m i l s . T h e c o a t i n g m a t e r i a l c o n ta ta i n s 8 3 p e r c e n t s o l id id s b y v o l u m e . D e te te r m i n e t h e W F T t o a ch ch i e v e a n 8 - m i l DF DF T .
W ith Thinn ing the Coati Coatin n g M ateria aterial l
N o t e :
T h e p e r ce n t o f s o lid s a n d t h i n n e r s ad d e d b y v o l u m e is ex p r e s se d i n d e cim ci m a l f o r m .
Example:
T h e sp sp e c if if ie ie d D F T i s 6 m i l s. s. T h e su su r f a ce ce a r e a s r e q u i r e s 5 g a l l o n s o f th th i n n e d p a i n t . T h e c o a ti ti n g m a t e r i al al c o n t a i n s 86 86 p e r c e n t s o li li d s , b y v o l u m e . T h e m a n u f ac ac t u r e r ' s i n s t r u c t io io n s s t a t e 1 ½ p i n t s o f t h i n n e r i s a d d e d t o e a c h g a l l o n o f c o a t in in g m a t e r i a l (16 (16 pints = 1 gallon). gallon). Determ ine the W FT to achieve a 6-mil DFT. DFT.
O-1
Appendix P Procedures for Dry Film Thickness Gauges (SSPC-PA2) and Example I.
P u rp o s e
D e t e r m i n i n g t h e t h i ck ck n e s s o f a h a r d e n e d c o a t i n g . II .
Eq u ip ip m mee n t
T h e n o n d e s t ru ru c t iv iv e g a u g e s d e s c r i b e d i n S SP SP S -P -P A 2 a r e g r o u p e d i n t o t w o g e n e r a l ca ca t e g o r i es es : T y p e I , m a g n e t ic ic p u l l o ff ff ga ga u g e . T y p e I I, I, fi fi x e d p r o b e o r c o n s t a n t p r e s s u r e p r o b e g a u g e s . III. III. Type I, Magnetic Pulloff Gauge Gauge
A. Description T y p e I , m a g n e t i c p u l l o f f g a u g e s , co co m m o n l y r e f e rr rr e d t o a s “ b a n a n a ” g a u g e s , m e a s u r e t h e c o a t in in g t h i c k n e s s o f a n o n - m a g n e t i c co co a t i n g o v e r a f e r r o u s m e t a l s u b s t r a t e . T h e g a u g e h a s a n e x p o s e d m a g n e t a t t a c h e d t o a sp sp r i n g . T h e am am o u n t o f t e n s i o n a p p l i e d o n t h e s p r i n g t o l if if t th th e m a g n e t f r o m t h e c o a t e d s u r f a c e is is d i r e c t l y p r o p o r t i o na na l t o t h e d i s ta ta n c e o f t he he m a g n e t f r o m t h e f e r ro ro u s s u r f a c e . B. Calibration 1.
U s e n o n m a g n e t i c, c, st st a n d a r d c a l ib ib r a te te d s h i m s , c o m m o n l y c hr hr o m e . P l as as t ic ic aan n d m y l ar ar sh s h i m s a re re n o t a c c e p t a b l e f o r ca ca l ib ib r a t i n g p u l l o f f g a u g e s b e ca ca u s e p l a s t ic ic o r m y l a r i s n o n a d h e r e n t a n d m a y c a u s e t h e m a g n e t w i t h in in t h e g a u g e t o l if if t p r e m a t u r e l y .
2.
S e l ec ec t a s h im im t h a t w i ll ll b e in in t h e r a n g e o f th t h e e x pe pe c t e d d r y f il il m t h i ck ck n e s s t o b e m e a s u r e d .
3.
P l ac a c e th t h e sh sh i m o n t h e p r e p a r e d s u b s t ra ra t e o r a n y c le le a n b a r e st st e el e l a n d p l a ce ce t he he g a u g e o n t h e shim.
4.
R ot o t a t e th t h e d i al a l fo fo r w a r d u n ti t i l t h e m a g n e t co co n t a ct c t s t h e sh sh i m .
5.
R o ta ta t e th th e d i a l b a ck c k w a r d s lo lo w l y a n d e v e n l y u n ti t i l t h e m a g n e t b r e a k s c o n ta ta c t an an d l if ift s u p . A c li li ck ck i n g s o u n d m a y b e h e a r d .
6.
I f t h e r ea e a d i n g d o e s n o t a g r e e w i t h t h e s h im i m t h i ck c k n e s s, s, ch ch e c k th t h e m a g n e t f or or c le le a n l in in e s s. s.
7.
I f t h e r e a d i n g i s st st il i l l n o t i n a g r e e m e n t w i t h t h e s h i m t h i ck ck n e s s, s, t he he g a u g e i s o u t o f ca c a l ib ib r a t i on on a n d s h o u l d b e r e - ca ca l ib ib r a t e d b y t h e m a n u f a ct ct u r e r o r r e p l a c e d . F o l lo lo w t h e m a n u f a c t u r e r ’s ’s i n st st r u c t io io n s fo fo r a d ju s t m e n t o r r e t u r n t h e g a u g e t o t h e m a n u f a ct ct u r e r f o r f a ct ct o r y a d ju s t m e n t . D o n o t a d ju s t t h e g a u g e y o u r s e l f .
P-1
8.
T he h e g a u g e i s t o c al al ib ib r a te t e d b e fo fo r e u s e , d u r i n g u s e , a nd n d a f te te r u s e t o v er e r i fy fy a c cu cu r a cy c y o f re re a d i n g s. s.
C. Procedure 1.
E ns n s ur u r e t he h e m a gn g n eett is is cl cl e a n. n.
2.
H o l d t h e c a li li br b r a te t e d g a u g e fi fi r m l y to to t h e co co a t e d s t ee ee l su su r f a ce ce a n d r o t a te te t h e d i a l f o r w a r d u n t il il the m agnet contacts the coated surface.
3.
R o t a te te t h e d i a l b a ck c k w a r d s lo lo w l y a n d e v e n l y u n t il il t h e m a g n e t b r e a k s c o n ta t a c t an an d l if if ts ts u p . A c li li ck ck i n g s o u n d m a y b e h e a r d . T h e f ol ol lo lo w i n g m a y i n f lu lu e n c e r ea ea d i n g s: s:
4.
a.
V ib i b ra r a t io io ns n s m a y p r e m a t u r e ly l y b re re a k t h e m a g n e ti ti c c o on n ta t a ct ct .
b .
So f t o r t a c k y c oa t i n g s m a y i n h i b it t h e l i fti n g o f t h e m a g n e t .
R e a d t h e co co a t in in g t h i ck ck n e s s o n t h e d i a l t h a t a li li g ns ns w i t h t h e m a r k e d l in in e o n t h e ga ga u g e a n d record the reading .
IV. Type II, Fix Fixed ed Probe Probe o r Cons tant Pressure Pressure Probe Probe Gauge s
A . D es e s cr c r ip ip t io io n T h e t y p e I I, I, f ix ix e d o r c o n s t a n t p r e s s u r e p r o b e g a u g e , m e a s u r e s t h e m a g n e t i c f lu lu x a s s o c ia ia t e d w i t h n o n - m a g n e t i c co co a t i ng ng s a p p l i e d t o f e r ro ro u s s u b s t r a t e s. s. F o r re re l i a bl bl e r e a d i n g s , th th e g a u g e s m u s t r e m a i n i n d i r e c t co co n t a c t w i t h t h e c o a t e d s u r f a c e u n t i l a r e a d i n g i s o b t a i n e d . T h e s e g a u g e s a r e n o r m a l l y fa fa s t er er a n d m o r e a c c u r a t e t h a n t h e m a g n e t i c p u l l o ff ff ga ga u g e s . B.
C al a l ib ib ra r a ti t i on on 1.
U s e n on o n m a g n e t ic i c or or p l a st s t ic i c c al a l ib ib r at a t ed e d s hi hi m s t an an d a r d s .
2.
S e l ec ec t a s h im im t h a t w i ll ll b e in in t h e e x p e ct ct e d r a n g e o f t he he d r y f il il m t h i ck ck n e s s t o b e m e a s u r e d .
3.
P l ac a c e th t h e sh sh i m o n t h e p r e p a r e d s u b s t ra ra t e o r a n y c le le a n b a r e st st e e l a n d p l a ce ce t he he g a u g e o n t h e shim.
4.
P la l a ce c e t he h e g a u g e fi fi rm rm l y a g a in in s t th th e s h im im a n d o b t ai ai n a r e a d i ng ng .
5.
I f t h e r e ad a d i n g d o e s n ot ot a g r e e w i t h th th e s h i m t h ic i c k ne n e s ss,, a d ju ju s t t h e g a u g e in i n a c co co r d a n c e w i t h th th e m a n u f a c t u r e r ’s ’s i n st st r u c t i o n s . A d ju s t m e n t i s n or or m a l l y co co n d u c t e d b y p r e s s i n g k e y s t o a d ju s t u p w a r d o r d o w n w a r d u n t il il t h e ga ga u g e r e a d i n g a n d t h e sh sh i m t h i c k ne ne s s ar ar e i n a g r e em em e n t .
C.
P-2
P r o ce d u r e 1.
E ns n s ur u r e t h e p ro r o b e i s c l e a n. n.
2.
S e t g a u g e t o r e a d i n d e s ir ir e d s ca c a l e, e, e i th th e r m i ls ls o r m i cr cr o m e t e rs rs .
3.
H o l d t h e c a li li b r at at e d g a u g e f ir ir m l y t o th t h e co co a t ed ed s t e e l s u r f a ce ce .
4.
R e a d t h e co co a t in in g t h i c kn k n e s s o n t h e d i g i ta ta l d i sp sp l a y . So m e g a u g e s w i l l s t o r e se se v e r al a l r e a d i ng n g s fo fo r d o w n l o a d i n g i n t o p r i n t e r a n d m a y b e ca ca p a b l e o f a v e ra ra g i n g r e a d i n g s. s.
Example:
Specifi Specifications cations requ ire th e up stream face of a rad ial ga te be coated . The ga te has the d imen sion sion s of 26 26 f e e t in in h e i g h t a l o n g t h e r a d i u s c u r v a t u r e a n d i s 10 10 fe fe e t i n w i d t h . T h e c o a t in in g t a b u l a t i on on s p e c i f ie ie s 2 coats of epoxy at 8 m ils per coat an d 1 topcoat of polyur ethan e at 3 m ils ils for for 19-m 19-m il DFT, m inimu m , for for the total system. S t e p 1 : D e t e r m i n e t h e n u m b e r o f s p o t m e a s u r e m e n t s re re q u i r e d o n a n a r e a ba ba s i s . Surface area of structur e: 26 feet x 10 10 feet feet = 260 squa re feet Surface area is less less than 300 squar e feet; feet; therefore, 5 spot spot m easure m ents are requ ired in each of tw o 100 100 squ are feet feet areas (total (total of 30 ind ividu al gauge read ings). Step 2: The DFT instru instru m ent is calibrated calibrated w ith a 20-m 20-m il shim. Step Step 3: An imag inary line is draw n horizon tally across th e gate at the m id elevation, eff effectivel ectively y d i v i d i n g t h e g a t e i n t o e q u a l lo lo w e r a n d u p p e r a r e a s . Fi v e s po po t m e a s u r e m e n t s a r e r a n d o m l y t a ke ke n in each area, consisting consisting of three three ind ividu al gauge read ings within a 1.51.5-inch-diam inch-diam eter circle circle per s p o t m e a s u r e m e n t . Th e f o ll llo w i n g a r e t h e r e su su l t s :
Lower Gate Area Gauge reading
Spot measurement (DFT in mils) A
B
C
D
E
1
18.2
20.6
21.0
16.7
26.4
2
18.6
19.1
21.8
17.1
29.8
3
17.8
20.4
20.8
16.8
29.0
Average
18.2
20.0
21.2
16.9
28.4
Upper Gate Area Gauge reading
Spot measurement (DFT in mils) A
B
C
D
E
1
22.6
20.4
18.6
19.5
29.3
2
22.1
21.7
18.3
19.9
31.0
3
21.9
21.3
19.4
19.2
30.4
Average
22.2
21.1
18.8
19.5
30.2
P-3
S te te p 4 : D e te te r m i n e m i n i m u m a n d m a x im im u m a c ce ce p t a n c e th th i ck ck n e s s cr cr i t e r ia ia . a. The specified specified coat ing thickn ess is is 1 19 9 mils. The allowable criteria are: Min imu m - 90 percent of sp ecified ecified th ickness (0.9 (0.9 x 19 mils) = 17.1 17.1 mils Ma ximu m - 150 150 percen t of specified specified thickness (1.5 (1.5 x 19 mils) = 28.5 mils b. b . Th e f o ll o w i n g e v a l u a t e s t h e r e s u l ts fo r t h i c k n e s s a c ce p t a n c e : ( 1 ) A v e r a g e s p o t m e a s u r e m e n t s t h a t a re re b e t w e e n t h e m i n i m u m s p e c i fi fi e d t h i ck ck n e s s o f 17.1 17.1 mils and the m aximu m specified specified th ickness of 28.5 28.5 mils (aa) Spot m easur em ents A , B, B, C, C, and E on the low er gate ar ea (18. (18.2, 2, 20.0, 20.0, 21.2 21.2,, and 28.4, 28.4, respectively) are acceptable. (bb) Spot m easu rem ents A, B, C, an d D on th e up per g ate area (22.2 (22.2,, 21.1 21.1,, 18. 18.8, 8, an d 19.5, 19.5, respectively) are acceptable. ( 2) 2) A v e r a g e s p o t m e a s u r e m e n t s t h a t a r e l e s s t h a n t h e 9 0 p e r c e n t m i n i m u m o f t h e specified specified th ickness of 17.1 17.1 mils at spot m easu rem ent D on the low er gate area (16.9) (16.9) are not acceptable. ( 3) 3) A v e r a g e s p o t m e a s u r e m e n t s t h a t a r e gr gr e a t e r t h a n t h e 1 50 50 p e r c e n t m a x im im u m s p e c i fi fi e d t h i ck ck n e s s o f 2 8 .5 .5 m i l s a t s p o t m e a s u r e m e n t E o n t h e u p p e r g a t e a r e a (3 0. 0. 2 ) a r e n o t acceptable. S te te p 5 : F r o m t h e a b o v e e v a l u a t i o n , th th e f o ll ll o w i n g c a n b e c o n c l u d e d : O n e a v e r a g e s in in g l e s p o t m e a s u r e m e n t ( D ) o n t h e l o w e r g a t e a r e a w a s l e ss ss t h a n t h e 9 0 p e r c e n t m inimum , and one average single spot measurem ent (E) on the up per gate area was greater t h a n t h e 1 50 50 p e r c e n t m a x i m u m . T h e r ef ef o r e , th th e c o a t i ng ng t h i c k n e s s d o e s n o t c o n f o rm rm t o t h e m i n i m u m a n d m a x i m u m t h i ck ck n e s s r e q u i re r e m e n t s a n d i s no no t a c c e pt pt a b l e. e. H o w e v e r , a d d i t i o n a l g a u g e r e a d i n g s a r e a l lo lo w e d t o b e t a k e n t o v e r i fy fy p r e v i o u s r e su su l t s. s. Several factors factors cou cou ld hav e affected affected the gau ge read ings. Possible Possible factors factors includ includ e ccalibration, alibration, d irty surface, soft or tacky coating su rface, proxim ity to edges or oth er steel m asses, c u r v a t u r e o f s t e e l, l, t i lt lt i n g o f p r o b e , p o s s i bl bl e o t h e r n e a r b y m a g n e t i c s o u r c e s , t e m p e r a t u r e e x t r e m e s , a n d v i b r a ti ti o n s .
P-4
Appendix Q Procedures for Discontinuity (Holiday) Testing (NACE RP 0188) I.
P u rp o s e
T o l oc oc a t e p i n h o l e s an an d o t h e r d e f e c ts ts in in h a r d e n e d c o a t in in g u s i n g lo lo w o r h i g h v o l t a g e i n s t ru ru m e n t s . II. II.
Using a Low Low V oltage Instr Instrume ume n ntt for Coating Coating Thic knesses of 20 Mils and Less Less
A . D es e s cr c r ip ip t io io n A l o w v o l t a g e , n o r m a l ly ly b e t w e e n 5 a n d 9 0 v o l t s D C , b a t t e r y p o w e r e d d e v i ce ce w i t h a w e t s p o n g e electric prob e is d ragged across the coated su rface to locate locate discontinu ities ities (pinholes) in the coating film film . Should d iscontinuities be encou ntered , an electric curren t will flow flow to the steel sub strate. This p rocess w ill close close an electrical electrical circuit w ithin the in in strum ent and set off an au d ible o r v i s u a l a la la r m . B.
E q ui u i p m en en t 1.
T h e fo fo ll l l ow ow i n g a r e t w o g e n e ra r a l t y pe p e s o f l ow ow v o l t a g e h o li li d a y t e st s t er e r s . E a ch ch u s e s a w e t s p on on g e p r ob e , b u t t h e y a re b a se d o n d i ffe r en t el e c tr ic a l pr in c ip l es . a.
E le le c t r o m a g n e t i c -s -s e n s it it i ve ve o r a s o l i d s t a t e el el e c t r on on i c r el el a y c i r cu cu i t t h a t , w h e n d i s co co n t i n u i t y i s d e t e ct ct e d , cl cl os os e s t h e c ir ir c u i t a n d p r o d u c e s a n a u d i b l e o r v i s u a l a la la r m . G e n e r a l ly ly , th th i s i n s t r u m e n t c a n b e fi fi e ld ld a d ju s t e d .
b .
A n el e ct r on ic re la x at io n os ci ll at o r c ir cu it m ea su re s th e d ro p in el e ct r ic al r es is ta n ce b e t w e e n t h e c o a t ing in g a n d t h e s t e e l s u b s t r a t e a n d p r o d u c e s a n a u d i b le a l a r m w h e n d i s c o n t i n u i t y i s de de t e c t e d . G e n e r a l ly ly , th th i s in in s t r u m e n t t y p e c a n n o t b e f ie ie l d a d ju s t e d .
C.
P r o ce d u r e 1.
E n s u r e t h e c o a t i n g i s s u f fi fi ci ci e n t l y d r y ( se se e c h a p t e r VI VI II II , su su b s e ct ct i o n 36 36 , “ D r y i n g , R e co co a t i n g , a n d Curing”) before testing.
2.
T es es t th th e i n s tr tr u m e n t ' s p o w e r s u p p l y b a t t e ri ri e s f or or s u f f ic ic ie ie n t p o w e r w i t h t h e b at at t e ry ry c h e ck ck sw itch. If the batteries are low, replace or recharg e the batteries.
3.
T e st st t h e in in s t r u m e n t f o r o p e r a ti ti on on a l u s e a n d c a li l i b ra ra t e it it i n a cc cc o rd rd a n c e w i t h t h e m a n u f a ct ct u r e r ’s ’s instructions or N AC E RP0188, RP0188, sections sections 3.3 and 3.4, 3.4, before its initial initial use.
4.
A t t ac ac h t h e e le l e c tr tr i ca ca l g r ou o u n d ( ne ne g a t i v e) e ) w i r e fr fr o m t h e i n s t ru r u m e n t t o t he he s t e e l su su b s t r a te te .
5.
W e t t he h e sp s p o ng n g e p r ob o b e w i th t h p o t ab ab le l e w a te te r
Q-1
N o t e : a.
A l o w -s - s u d s in in g w e t t in in g a g e n t s uc u c h a s th th a t u s e d i n p h o t og og r a p h ic ic d e v e lo lo p m e n t c an an b e a d d e d t o t h e p o t a b l e w a t e r a t a r a t i o o f ½ fl fl u i d o u n c e t o 1 g a l lo lo n o f w a t e r t o i n c re re a s e sensitivity.
b .
T h e u s e o f d e t e r g e n t w e t t in g s o lu t io n s i s n o t p e r m i tt e d b e c a u s e a b u b b l e m a y f o r m o v e r a d e f e ct ct , r e n d e r i n g i t u n d e t e ct ct a b l e .
6.
T u rn rn t h e i ns n s t ru r u m e n t sw s w i t ch ch t o t h e “ o n ” p o si s i t io io n .
7.
T h e s p o n g e is i s to to b e m o v e d o v e r t h e co co a t in in g s u r f ac ac e at at a b o u t 1 f o ot ot p e r s e co co n d , u s in in g a d o u b l e p a ss ov e r e a c h a r e a a n d a p p l y in g su f fic i e nt p r e ss u re t o k e e p t he s u rf a c e w e t .
8.
T h e sp sp o n g e s h o u l d b e k e p t sa sa t u r a t e d , b u t n o t d r i p p i n g w e t , w h i l e m o v i n g o v e r t h e c o a t in in g .
9.
W h e n a d i sc sc o n ti ti n u i ty t y i s d e t e ct ct e d , th th e s p o n g e is is t o b e t u r n e d o n e d g e t o d e t er er m i n e t h e e xa xa c t spot of the defect, and the spot is to be marked for repair. Use a greaseless ma rker that can be easily easily clean clean ed off. off.
1 0. 0. I f w e t t i n g s o l u t i o n s a r e u s e d , t h e s o l u t i o n s m u s t b e c o m p l e t e l y r i n s e d o f f b e f o re re a p p l y in in g t h e repair coating. III. III. Usin g Hig h V oltage oltage Instrum Instrum ent for Coating Coating Thickness of Greater Greater Than 20 Mils
A . D es e s cr c r ip ip t io io n A high -voltage d evice, nor m ally in in excess of 800 800 volts volts DC, w ith w et spon ge electric electric prob e is is p a ss ed ov er th e co a te d su r fa ce to loca lo ca te d is co n ti n u it ie s ( p in h ol e s) in th e c o a ti n g fi lm . Sho Sh o u ld d i s c o n t i n u i t ie ie s b e e n c o u n t e r e d , t he he e l e c t r ic ic d e v i c e w i l l sp sp a r k t h r o u g h t h e a i r g a p a t t h e d i s co co n t i n u i ty ty a n d p r o d u c e a n a u d i b le le o r v is is u a l al al a r m . A g e n e r a l ru ru l ee- o f -t -t h u m b f or or d e t e r m i n i n g the requ ired voltage is 100 to 125 125 volts per m il; il; how ever, it is best best to consul t the man ufactu rer to p r e v e n t d a m a g in g t h e co a t in g . B.
E q ui u i p m en en t 1.
2.
Q-2
T he he f o ll ll o w i n g a r e t w o g e n e r a l ty ty p e s o f hi hi g h v o l ta ta g e h o l id id a y t e s te te r s: s: a.
P u l s e t y p e —d —d i s ch ch a r g e s a cy cy c li lin g , h i gh gh - v o lt l t a ge ge p u l s e
b .
D i re ct cu r r e n t — d is ch a r g e s co n t in u o u s v o lt a g e
T he h e f o ll ll o w i ng n g a r e g e n e r a l t y p e s o f e l ec ect r od od e s a n d p r ob ob e s : a.
H a l ff - or or f u ll ll -c -ci r cl cl e s p r i n g e l e ct ct r o d e s us us e d f o r p i p e s
b .
Ph osp hor bron ze bru sh p robes
c.
C on o n d u c t iv iv e r u b be b e r s ttrr ip i p p r o be be s
C . P r o ce d u r e 1.
E n s u r e t h e co co a t i n g i s s u f f ic ic ie ie n t ly ly d r y b e fo fo r e t e s ti ti n g . ( Se Se e c h a p t e r VI VI II II , s u b s e c ti ti o n 3 6, 6, “ D r y i n g , R e co co a t in in g , a n d C u r i n g . ” )
2.
I f m o i s t ur u r e i s p r e se se n t o n t h e c o a te te d s u r f ac a c e , d r y t h e s u r f ac a c e b e fo fo r e t es es t in in g b e c a u s e m o i st s t u re re w ill indicate inv inv alid discontinu ities. ities.
3.
T es e s t th th e i n s tr tr u m e n t fo fo r o p e r a t io io n a l u s e a n d c a li li b ra ra t e it it in in a c co co r d a n c e w i t h t h e m a n u f ac a c tu t u r e r ’s ’s instructions or N AC E RP 0188, sections sections 4.5 and 4.6, 4.6, before its initial initial use.
4.
A d j u s t t h e in i n s tr tr u m e n t t o t h e p r o p e r v o l ta ta g e s e tt tt i n g f or or t h e c oa oa t in i n g t h i ck ck n e s s. s.
5.
A t t ac ac h t h e e le l e c tr tr i ca ca l g r ou o u n d ( n e g a t i ve v e ) w i r e fr fr o m i n s t r u m e n t t o t h e s te te e l su su b s t r a te te .
6.
T u rn rn t h e i ns n s t ru r u m e n t sw s w i t ch ch t o t h e o n p o s it it io io n .
7.
To u c h t h e p r o b e t o a b a r e c o n d u c t iv iv e (s ( st e e l) l) su su b s t r a te te t o v e r if if y th th a t it it i s p r o p e r ly ly g r o u n d e d . E le le c t ri ri c s pa pa r k s s h o u l d b e s e e n , o r a n a l a r m s i g n a l s h o u l d b e a c t i v a t e d .
8.
U s in i n g a s in in g l e p a s s, s, m o v e t h e p r o b e o v e r t h e c o a t ed ed s u r f a ce ce a t a r at a t e o f ab ab o u t 1 fo o t p e r second.
9.
W h e n a d i s co co n t i nu n u i t y is is d e t e ct c t e d, d, m a r k t h e s p o t f o r r e p a i r. r . U s e a g r e a s el e l e ss ss m a r k e r th th a t b e easily easily clean clean ed off. off.
Q-3
Appendix R Procedure for Mechanical (Pulloff) Adhesion Testing Testing (ASTM D 4541; Annex A2) A . P u rp o s e
T o d e t e r m i n e t h e a d h e s i v e s t r en en g t h b e t w e e n a f u l ly ly c u r e d c o a t in in g a n d t h e s u b s t r a t e . B.
D e sc s c ri p ptt i on on
T h e a d h e s io io n t e s t e r m e c h a n i ca ca ll ll y m e a s u r e s t h e r e l a t iv iv e s t r e n g t h o f a d h e s i on on b e t w e e n a c o a t in in g a n d t h e s u b s t r a t e o r b e t w e e n c o a t in in g l a y e r s . A n a l u m i n u m p u l l o ff ff s tu tu b ( d o ll ll y ) is is a d h e s i v e ly ly b on d ed to th e c o a ti n g an d al lo w ed to cu r e. A p u ll in g fo r ce o n th e b on d ed d olly ol ly is co n ti n u ou sl y increased u ntil th th e dolly d etaches or a specific specific force force is achieve d . C.
Eq ui u i pm p m e nt nt
There are severa l different different typ es of p ulloff adh esion testers. testers. The typ e II tester, cited cited in ASTM D 4541, 4541, ann ex A.2, A.2, is the Elcom Elcom eter Mod el 106. 106. This mod el is the m ost com com m only use d. Elcometer Mod el 106 106 is is available in in six scale scale range s. The scale m ost comm only u sed is 0 to 1,00 1,000 0 pou nd s per s q u a r e i n c h (p (p s i ), ), a n d i t i s d i sc sc u s s e d b e l o w . A s t a n d a r d 3 / 4 -i -i n c h -d -d i a m e t er er a l u m i n u m d o l l y is is u s e d w i t h t h e E lc lc om om e t e r M o d e l 10 10 6. 6. D . P ro ce ce d ur u re
1.
S e le le c t t h e sp sp o t w h e r e t h e d o l ly ly w i l l b e b o n d e d t o t h e c o at a t in in g . Th e s e le le ct ct e d a r e a m u s t b e la la r g e e n o u g h t o a c c o m m o d a t e t h e f e e t o f t he he i n s t r u m e n t . D o l li li e s s h o u l d b e l o c a t e d a t l e a s t 2 i n c h e s f r o m a n y s u r f a c e o b s t r u c t io io n s a n d h a v e a t l e a s t 1 f o o t o f v e rt rt i c a l cl cle a r a n c e t o a c c o m m o d a t e i n s e r t in in g t h e i n s t r u m e n t i n t h e d o l ly ly .
2.
U s e a s u i ta ta b l e s ol o l v e n t w i p e t o r e m o v e s u r f ac ac e c on on t a m i n a n ts ts s u c h a s d i r t, t, d u s t , gr gr e a s e , a n d o i l f r o m t h e t e s t s p o t . W i p e a l l m o i s t u r e f r o m s u r f a ce ce a n d t h e n s o l v e n t w i p e .
3.
T h e m a n u f a ct ct u r e r r e co co m m e n d s t es es t in in g o n l y o n f la l a t su su r f a ce ce s ; h o w e v e r , cu cu r v e d s u r fa f a ce ce s o f 24 24 i n c h r a d i u s a n d g r e a t e r c a n b e t e st st e d . Fo r c u r v e d s u r f a c e s w i t h a r a d i u s o f l e s s t h a n 2 4 i n c h e s, s, th th e d o l l y n e e d s t o b e g r o u n d d o w n t o m a t c h t h e e x is is t in in g m e t a lw lw o r k r a d i u s . T h e f o ll ll o w i n g m a t c h e s t h e d o l l y ty ty p e w i t h t h e s u r f a ce ce : •
F la la t s ur u r f ac a ce s - U se s e st st an a n d a r d d o ll l li es es
•
C u r v e d s u r f a ce ce s - U s e d o l li li e s w it h a ra r a d i u s t h a t m a tc t c h e s t h e su su r fa f a ce ce r a d iu i u s t o b e te te s t e d . T h e m a n u f ac ac t u r e r w i l l fa fa b r i ca ca t e d o ll ll ie ie s f o r a s p e ci ci fi fi e d r a d i u s a n d t h e f o ll ll ow ow i n g curvatures:
R-1
4.
"
C o n c a v e - o u t e r r a d i u s (e x a m p l e : p i p e e x t e r io io r )
"
C o n v e x - in in n e r r a d i u s ( e xa xa m p l e : p i p e i n t e r io io r )
T o p r o m o t e a d h e s io io n o f t h e d o l ly ly t o t h e fo fo l lo lo w i n g s u r fa f a ce ce s , r o u g h e n t h e t es e s t s p ot ot a r e a u s in in g : •
L ig ig h t s an a n d p ap a p e r on on g lo l o ss ss y su s u r fa f a ce ce s
•
C oa o a rs rs e r s a n d p ap a p e r o n u ne n e ve v e n s u rf r f a ce ce s
5.
W i p e cl cl ea e a n an an y g r i t an a n d r e p e a te te d l y so s o lv lv en e n t w i p e o n t h e t es e s t sp sp o t .
6.
S o lv lv e n t c le le a n a n d r o u g h e n t h e d o ll l l y s ur u r f a ce ce u s i n g 40 40 -6 -6 0 g r it i t s a n d p a p e r o n t h e d o l ly ly ’s ’s fl fl a t s u r f a ce ce ( t a p e r e d e n d ) .
7.
M i x t h e a d h e s iv iv e a c co co r d i n g to to t h e i n st s t r u c ti ti o n s. s. T h e a d h e s iv iv e i s n o r m a l ly l y an an e p o x y . A p p l y a t h i n , s m o o t h l a y e r o f a d h e s i v e t o t h e p r e p a r e d t e s t d o l ly ly s u r f a c e .
8.
P la l a c e t h e d o ll ll y on on t h e p r e p a r e d t e st st sp s p o t a n d p r e ss s s fi fi r m ly l y to t o ssq q u e e z e o u t e xc xc e ss ss ep ep o xy xy . D o n o t t w i s t th th e d o l ly ly .
9.
R e m o v e a n y e xc xc e ss ss ep ep o x y a r o u n d t h e p e r ip i p h e r y o f t h e d o l ly ly w i t h o u t d i st s t u r b i ng n g t h e d o l ly ly .
1 0. 0. A l lo lo w t h e e p o x y to to f u ll l l y c u r e. e . D e p e n d i n g on on t h e t e m p e r a t u r e , c u r i n g ti ti m e m a y t a k e u p t o 2 4 h o u r s . F o ll ll o w t h e a d h e s i v e m a n u f a c t ur ur e r ’s ’s i n st st r u c t i o n s . 1 1. 1. F o r v er er t i ca ca l , o v e r h e a d , o r ot ot h e r s u r f a ce ce s , s e c u r e t h e d o ll ll y b y t a p i n g o r u s i n g t h e m a g n e t i c c la la m p t h a t i s su su p p l ie ie d w i th th t h e t e s t e r k i t. t. E n s u r e t h a t t h e m a g n e t i c c la la m p d i s c k e e p e r i s r e m o v e d b e f o r e us us e . N o t e : D o l lie s a p p li e d w it h i n s u f fic ie n t a d h e s i v e o r n o t p e r p e n d ic u l a r ly p o s it io n e d a r e n o t a c c e p t a b l e an an d w i ll ll p r o v i d e e r r o n e o u s r e su su l t s . A f t e r t h e e p o x y h a s c u r e d , m a k e a c i r c u l a r cu cu t t h r o u g h t h e c o at at i n g t o t h e su su b s t r a te te a r o u n d t h e d o l l y w i t h t h e c u t t i n g t o o l t h a t i s p r o v i d e d w i t h t h e t e s te te r k i t . T h e c u t t i n g t o o l f it it s o v e r t h e d o l l y . K it it s a r e p r o v i d e d w i t h a s m a l l d i a m e t e r b a r t o a s s is is t in in t h i s o p e r a t i o n . 1 2. 2. I f t e s t in in g a f l ex ex i b le le c o a t in in g o r s u b s t r a t e , p l a ce ce t h e s u p p o r t r i n g o v e r t h e t e s t d o l ly ly . Se t t h e d r a g i n d i c a t o r ( s t e el el p i n p r o je je c t in in g t h r o u g h a s l i t o n t h e s h a f t a t t h e s c a l e r a n g e ) t o z e r o . 1 3. 3. S li li p t h e t e st st e r s u p p o r t r i n g ( cl cl a w a t t h e b o t t o m c e n te te r o f th th e te te s t e r ) i n t h e g r o o v e o f th th e d o l l y . E n s u r e t h a t t h e t e s t e r i s p e rp rp e n d i cu cu l a r a n d t h a t t h e 3 f e e t o f t h e t e s t e r b e a r e q u a l l y o n t h e c o a t e d s u r f a ce ce . N o t e : Sh o u l d t h e t e st e r b e t i lt e d , o n e o f t h e f e e t n o t b e se c u r e , o r t h e b e a r i n g o f t h e i n s t r u m e n t b e u n e q u a l , a s h e a r in in g f o r c e m a y b e i m p a r t e d t o t h e c o a t in in g , r e s u l t in in g i n a n e r r o n e ou ou s r e a d i n g . 1 4. 4. S lo lo w l y a n d c on on t in in u o u s l y r ot ot a t e t h e t e s te te r h a n d w h e e l in in a cl cl o c k w i s e d i r ec ec t i on on u n t i l t h e d o l l y is is p u l le d fr e e o r a s p e c ifie if ie d m a x im u m t e n s i o n i s a c h i e v e d .
R-2
1 5. 5. R e a d t h e h i g h e s t v a lu lu e a t t a i n e d a t t h e b o t t o m o f t h e d r a g i n d i c a to to r i n ps ps i . I f t h e d o l l y d i d n o t p u ll fr e e, r ep or t t h e r es u lt a s g r ea te r th a n th e m a xi m u m ca p a ci ty of t h e in st r u m en t ( i.e. i. e. , 1 ,000 ,0 00 p si fo r th e E lc om et er M od el 10 6). 6) . 1 6. 6. A l w a y s r e s e t t h e d r a g i n d i c a t o r t o z e r o a f t e r t e s ti ti n g . Fa i lu lu r e t o r e s e t w i ll ll r e su su l t i n a d i st st o r t e d o r p e r m a n e n t l y d a m a g e d h e l i ca ca l s p r in in g . 1 7. 7. R e p o r t o n e o r a c o m b i n a t i o n o f t h e f o l lo lo w i n g t y p e s o f f a il ilu r e : •
•
A d h e s iv e "
F a il il u r e b e t w e e n t h e s u b s t r a t e a n d t h e f ir ir s t (p (p r i m e ) co co a t
"
F a il il u r e b e t w e e n a n y t w o c o a t s
C o h e s iv e "
•
F a il il u r e o r a b r e a k w i t h i n a n y o n e c o a t in in g l a y e r
G lu e "
A d h e s i v e fa fa i l u r e o f th th e a d h e s i v e g lu lu e b e t w e e n t h e d o ll ll y a n d t h e c o a t in in g ( co co a t in in g remains intact and glue remains on either the coating or dolly)
"
C o h e s i v e f a il il u r e o f t h e a d h e s i v e g l u e ( g lu lu e r e m a i n s o n t h e c o a t in in g a n d d o l ly ly )
R-3
Appendix S Procedure for Hydraulic Adhesion Testing (ASTM D 4541; Ann ex A3) A . P u rp o s e
T o d e t e r m i n e t h e a d h e s i v e s t r en en g t h b e t w e e n a f u l ly ly c u r e d c o a t in in g a n d t h e s u b s t r a t e . B.
D e sc s c ri p ptt i on on
T h e a d h e s i o n t e s t e r u s e s a h y d r a u l i c sy sy s t e m t o m e a s u r e t h e r e l a t i ve ve s t r e n g t h o f a d h e s i o n b e t w e e n a c o a t in in g a n d t h e s u b s t r a t e o r b e t w e e n c o a t i n g l ay ay e r s . A u n i fo fo r m t e n s il il e lo lo a d i s a p p l ie ie d t h r o u g h a h o l e in in t h e c e n t e r o f a p u l l st st u b u s i n g a h y d r a u l i c pi pi s t o n a n d p i n . A n a l u m i n u m p u l l o f f s t u b ( d o l ly ly ) is is a d h e s i v e l y b o n d e d t o t h e c o a t in in g a n d a l lo lo w e d t o c u r e . A p u l li li n g f o r ce ce o n t h e b o n d e d d olly olly is continu ou sly sly increased un til the d olly olly d etaches or a specific specific force is is achieved . R e p r o d u c i b l e r e su su l t s a r e a c h i e v e d b e c a u s e t h e a p p l i e d t e n s i l e lo lo a d i s c o ns ns i s t en en t . C.
Eq ui u i pm p m en en t
The self-ali self-aligning gning ty pe III tester cited cited in ASTM D 4541, 4541, annex A3, is the Hate M ark VII. Testers are av ailable in th e follow follow ing th ree ra ng es: (1) 0 to 1,500 1,500 p si, (2) 0 to 2,250 2,250 p si, si, an d (3) 0 to 3,000 3,000 psi. D . P ro ce ce d u re re
1.
S e le l e ct ct t h e sp sp o t w h e r e t h e d o l ly ly w i l l b e b o n d e d t o t h e c o a ti ti ng n g . Th e s e le le ct ct e d a r e a m u s t b e la la r g e e n o u g h t o a c c o m m o d a t e t h e f e e t o f th th e i n s t r u m e n t . D o l li li e s s h o u l d b e l o c a t e d a t l e a s t 2 i n c h e s f r o m a n y s u r f a c e o b s t r u c t io io n s a n d p r o v i d e d a t l e a s t 1 f oo oo t o f v e r t i ca ca l c l e ar ar a n c e t o a c co co m m o d a t e i n s e r t in in g t h e i n s t r u m e n t i n t h e d o l l y .
2.
U s in in g a s u i t a b le le s ol ol v e n t w i p e , r e m o v e s u r f ac ac e c on on t a m i n a n ts ts s u c h a s d i r t, t, d u s t , gr gr e a s e , a n d o i l f r o m t h e t e s t s p o t . W i p e a l l m o i s t u r e f r o m s u r f a ce ce a n d t h e n s o lv lv e n t w i p e .
3.
T h e m a n u f a c tu tu r e r r e c o mm mm e n d s t e st s t in in g o n l y on o n f la la t s u rf r f a ce ce s ; h o w e v e r , cu c u r v e d s u r f a ce ce s o f 2 44- in in c h r a d i u s a n d g r e a t e r c a n b e t e s t e d . Fo r c u r v e d s u r f a c e s w i t h a r a d i u s o f l e s s t h a n 2 4 i n c h e s, s, t he he d o l ly ly n e e d s t o b e gr gr o u n d d o w n t o m a t c h t h e e x is is t in in g m e t a lw lw o r k r a d i u s . T h e f o ll ll o w i n g m a t c h e s t h e d o l l y t y p e w i t h t h e s u r f a c e : •
F la la t s ur u r f ac a ce s - U se s e st s t an a n d a r d d o ll l li es es
•
C u r v e d s u r f a ce ce s - U s e d o l li li e s w it h a r a d iu i u s t h a t m a tc t c h e s t h e su s u r f a ce ce r a d i u s t o b e te te s t ed ed . T h e m a n u f ac ac t u r e r w i ll ll f ab ab r i c at at e d o ll ll ie ie s f o r a s p e c i fi fi e d r a d i u s a n d t h e f o l lo lo w i n g curvatures: "
C o n c a v e - o u t e r r a d i u s (e (e x a m p l e : p i p e e x t e r io io r )
"
C o n v e x - in in n e r r a d i u s (e (e x a m p l e : p i p e i n t e r i o r )
S-1
4.
C l e a n t he he b o n d i n g s u r f a ce ce o f t h e l o a d f ix ix t u r e, e , th th e T e fl fl on on p l u g , a n d t h e c o a ti ti ng ng a r e a t o b e t e s t e d w i t h s o lv lv e n t .
5.
L ig ig h t l y s a nd nd t h e t es e s t ar ar e a t o a c hi h i e v e a n e v e n , s m o o t h s u r fa fa c e a n d w i p e c l ea ea n . Re p e a t th th e s o lv lv e n t w i p e .
6.
I n s er er t t h e t e fl fl o n p l u g in i n t o th t h e l o ad a d i n g f ix ix t u r e u n t i l t h e p l u g t i p p r o t ru r u d e s fr fr o m t h e s u r f a ce ce .
7.
A p p l y a th t h i n co co a t of of a d h e s i v e e p o x y to to t h e b o n d i n g s u r f ac a c e o f t h e fi fi xt xt u r e , ta ta k in i n g c ar ar e n o t t o get epoxy on the plug.
8.
P r e ss s s th th e l o ad a d i n g fi f ix t u r e on on t o t h e co co a t in in g a n d w i p e t h e e x ce ce s s a d h e s i v e e p ox o x y fr fr o m a r o u n d t h e p e r i p h e r y o f t h e f i x tu tu r e .
9.
R e m o v e th t h e te te f lo l o n p l u g an a n d a l l ow ow t h e a d h e s i v e e p o x y t o cu cu r e i n a c co co r d a n c e w i t h t h e m a n u f a c t ur ur e r ’s ’s i n s tr tr u c t io io n s .
1 0. 0. C o n n e c t t he he t e s te te r t o th t h e l o ad a d f ix ix t u r e . 1 1 . E n su su r e t h e g au a u g e i s se s e t a t z e ro ro . 1 2. 2. I n c r e a s e t h e p r e s s u r e s lo lo w l y b y t u r n i n g t h e h a n d l e cl cl o c k w i s e u n t i l t h e f ix ix t u r e p u l ls ls fr fr e e o r u n t i l a s p e c if if ie ie d p r e s s u r e i s a c h ie ie v e d . 1 3. 3. D i r e c t ly ly r e a d t h e g a u g e v a l u e a t t a i n e d i n p s i. i. I f t h e d o l l y d i d n o t p u l l f r e e , r e p o r t t h e r e s u l t a s g r e a t e r t h a n t h e m a x i m u m c a p a c i t y of of t h e i n s t ru ru m e n t . 1 4. 4.
R e p o r t o n e o r a c o m b i n a t i o n o f t h e f o ll llo w i n g t y p e s o f f a i lu lu r e : •
•
A d h e siv e "
F a il il u r e b e t w e e n t h e s u b s t r a t e a n d t h e f ir ir s t (p (p r i m e ) co co a t
"
F a il il u r e b e t w e e n a n y t w o c o a t s
C o h e s iv e "
•
F a il il u r e o r a b r e a k w i t hi hi n a n y o n e c o a t in in g l a y e r
G lu e "
A d h e s i v e fa fa i l u r e o f th th e a d h e s i v e g lu lu e b e t w e e n t h e d o ll ll y a n d t h e c o a t in in g ( co co a t in in g r e m a i n s in t a c t a n d g l u e r e m a i n s o n e i t h e r t h e co co a t i n g o r d o l l y )
"
S-2
C o h e s i v e f a il il u r e o f t h e a d h e s i v e g l u e ( g lu lu e r e m a i n s o n t h e co a t i n g a n d d o l ly ly )
Appendix T Procedure for Measuring Dry Film F ilm Thickness by Destructive Destructive Means With Tooke Gauge (ASTM D 4138) A . P u rp o s e
T o d e t e r m i n e t h e d r y f il il m t h i c k n e s s a n d t h e n u m b e r o f in in d i v id id u a l co co a t s o f a c o a t in in g s y s t e m B.
D e sc s c ri p ptt i on on
T h e To To o k e g a u g e is is u s e d t o c u t th th r o u g h t h e h a r d e n e d c o a t i n g t o th th e s u b s t r a t e . O n e s i d e o f th th e c u t i s m a d e a t a s p e c i fi fi c a n g l e t h r o u g h t h e c o a t in in g . A m i cr cr o s c o p e w i t h a g r a d u a t e d ( r et et i cl cl e ) s ca ca l e , a t t a c h e d t o t h e g a u g e , i s u s e d t o m e a s u r e t h e e x p o s e d c oa oa t i n g p e r p e n d i cu cu l a r t o t h e s p e c if if ic ic c u t a n g l e t o d e t e r m i n e t h e d r y f i lm lm t h i c k n e s s . T h e n u m b e r o f a p p l ie ie d c o a t s a n d t h e i n d i v i d u a l t h i c kn kn e s s e s c a n a l s o b e d e t e r m i n e d , p r o v i d e d t h a t c o a t in in g l a y e r s c a n b e i d e n t i f ie ie d b y c o l o r d i ff ff er er e n c e o r b y a d i st st i n c ti ti v e l in in e . T h i s m e t h o d i s c o n s id id e r e d d e s tr tr u c ti ti v e b e ca ca u s e th th e c u t m a d e in in t h e c o a t in in g i s a n i n t e n t io io n a l d e fe fe c t , u n l es es s r e p a i r e d . T h e T oo oo k e g a u g e i s m o s t o ft ft e n u s e d i n evalu ation of coating coating failures. C.
Eq ui u i pm p m en en t
A T o o k e g a u g e , e it it h e r a l u m i n u m o r p l as as t ic ic b o d y , w i t h a n i ll ll u m i n a t e d 5 0X 0X m i cr cr o s co co p e a n d r e t ic ic le le ( ca ca l ib ib r a t e d ) s c a l e . I t in in c l u d e s t h r e e c u t t i n g t i p s a n d a m a r k e r p e n . D . P ro ce ce d ur u re
1.
S e le le ct ct a n a r e a o f th e c o a ti ti n g t o te te s t a n d d r a w a b o u t a 1 -i -in c h s t r a ig ig h t li li n e w i t h th th e m a r k e r p e n . T h e m a r k s e r v e s a s a r e f e r en en c e l in in e .
2.
S el el e ct ct t h e p r o p e r c u t t in in g t ip i p f or or t h e e x is is t in in g c oa oa t in in g t h i c k n es es s t o b e m e a su su r e d . T h e f o ll ll ow ow i n g a r e t h e t h r e e t y p e s o f c u t t i n g t i p s a n d t h e i r a s s oc oc i a t ed ed t h i ck ck n e s s r a n g e s :
3.
•
1 0X 0X t ip i p : 0 t o 3 m i ls ls c o oaa ti t i ng n g th t h i ck ck n e ss ss
•
2 X t ip i p : 3 t o 2 0 m i ls ls c o oaa ti t i ng n g th t h i ck ck n e ss ss
•
1 X t ip i p : 20 t o 5 0 m i ls ls c o oaa ti t i ng n g t h ic ick n e ss ss
A f t e r s e le le c ti t in g t h e p r o p e r c u t t in in g ti t i p , p l a ce ce t he he c u t t i ng ng t ip i p a n d t w o g u i d e s tu t u d s a ga g a i ns n s t th th e c oa oa t i n g s u r f a c e, e, w i t h t h e c u t t i n g t i p ju ju s t a b o v e t h e m a r k e d l in in e . A l i gn gn t h e f o re re a r m t o c u t a c r o s s (p (p e r p e n d i cu cu l a r t o ) t h e m a r k e d l in in e . D r a w t h e f o r e a r m s t r a i g h t b a c k w i t h s u f f i ci ci e n t p r es su r e t o c u t co n ti n u ou sly sl y th r ou g h th e c o a ti n g in to th e s u b st r a te . M a in ta in th e t h r ee p oi n t s u r f a c e co co n t a c t (c (c u t t e r a n d 2 g u i d e s t u d s ) t o e n s ur ur e a s t r a ig ig h t a n d v e r t i c a l c u t . T h e l e n g t h o f c u t i n t o t h e s u b s t r a t e n e e d s t o e x t e n d s li li g h t l y b e y o n d t h e m a r k e d l in in e .
T-1
4.
V ie ie w t h e c u t t h r o u g h t h e l ig ig h t e d 5 0 X m i c r o sc sc o p e a n d f o c us u s o n t h e co c o a t in in g o n e i t he h e r s id id e o f t h e e x p o s e d s u b s t r a t e . F oc oc u s a n d a li li g n t h e r e t i cl cl e s c a le le p e r p e n d i cu cu l a r t o t h e cu cu t . T h e co co a t i n g o n o n e s i d e o f t h e c u t w i ll ll be be s m o o t h e r t h a n o n t h e o p p o s it it e si si d e o f t h e c u t . I f t h e c u t t i n g t ip ip w a s c o r r ec ec t ly ly p o s i t io io n e d , t he he s m o o t h e r s i d e w i ll ll b e o n t h e l e ft ft . A l w a y s m e a s u r e o n t h e smoother side.
5.
L in in e u p t h e r e t ic ic le le s ca ca l e a c r o ss ss t h e cu cu t o n t h e s m o o t h er e r s id id e a n d c o u n t th th e n u m b e r o f d i v i s io io n s f o r e a ch ch c o a t i n g l a y e r in in t h e t o t a l s y s t e m . Be g i n a t t h e e x p o s e d s u b s t r a t e a n d w o r k t o w a r d s t h e m a r k e r l in in e .
6.
Th e c o a ti ti n g t h i ck ck n e s s is is d e t e r m i n e d b y t h e n u m b e r o f co co u n t e d d i v is i si o n s o n th th e r e t i cl cl e s c al a l e. e. T h e f o ll ll ow ow i n g p r o v i d e s t h e t h i ck ck n e s s f o r e a c h d i v i s io io n f or or e a c h c u t t i n g t i p :
7.
Cutting titip
1 - Division represented on on re reticle sc scale
10X
0.1 mil
2X
0.5 mil
1X
1.0 mil
H el e l p fu f u l h in in t s : •
W h e r e t h e p r i m e r i s a n i no no r g a n i c z i n c o r ga g a l va va n i z e d z i n c , i t i s d i ff f f ic ic u lt lt t o d i s ti ti n gu gu i s h t h e z i n c fr fr o m t h e s u b s t r a t e . T o d i f fe fe r e n t ia ia t e b e t w e e n s t e e l su su b s t r a t e a n d z i n c , u s e a 5 p e r c e n t s o lu lu t i o n o f c o p p e r s u l fa fa t e a n d d i s t il il le le d w a t e r . T h e s t e e l s u b s t r a t e w i l l tu tu r n a c o p p e r color, and the zinc will tur n black.
•
F o r d a r k - co co lo lo r e d c o a t in in g s , u s e a li li q ui ui d e r a s e r w h i t e -o -o u t i n st s t e a d o f t h e fe fe lt lt t ip ip m a r k e r .
•
T h e t h i ck ck n e s s o f co co a ti ti n g c hi h i p s c a n b e m e a su s u r e d b y v i e w i ng ng t h e c ro r o s s s e ct ct i on on o f t h e coating chip throu gh the Tooke gau ge. (Each (Each d ivision ivision is equ al to 1 m il.) il.)
T-2
Appendix U Procedures for SSPC-VIS 2 (2000 Revision) A . P u rp o s e
T o ev ev a l u a t e t h e a m o u n t a n d d i s t r i b u t i o n o f r u s t o n c o a t ed ed s u r f a c e s. s. B.
D e sc s c ri p ptt i on on
T h i s a p p e n d i x p r o v i d e a s t a n d a r d m e t h o d o f e v a l u a t i n g a n d q u a l if if y i n g t h e d e g r e e o f r u s t o n p a i nt e d f e r r o u s (s t e e l o r i r o n ) su r f a c e s u si n g p i ct o r i a l im a g e s ( c olo ol o r a n d b l a c k a n d w h i t e p h o to g r ap h s) w i t h a g i ve n r u st p e rc e n t a g e a n d d i st ri b u ti o n. Th e r e su l ts a re re p or te d i n a r u st g r a d e s c a le le f r om om 1 0 (l (l ea ea s t r u s t ed ed ) t o 0 ( m o s t r u s t e d ) , a n d r u s t d i st st r i b u t i o n i s n o t e d b y S ( s p o t r u s t ) , G ( g e n e r a l r u s t ) , a n d P ( p i n p o i n t r u s t ). ). C . P ro ro ce ce d u re re
1.
S e le l e ct ct a n a r e a o r a re r e a s fo r e v a l u a ti ti o n . A r e a si si z e m a y r a n g e fr fr o m v e r y s m a l l t o v e r y la la r g e , b u t s h o u l d b e r e p r e s e n t a t i v e o f t h e s tr tr u c tu tu r e t y p e b e in in g e v a l u a t e d . F or or c o m p l ex ex s tr tr u c tu tu r e s , s u c h a s I - b e am am s o r c h a n n e l s , t h e e n t i r e s t r u c t u r e c a n b e e v a l u a t e d , o r t h e e v a l u a t i o n c a n b e l i mi mi t e d t o c e r t ai ai n p o r t i on on s o f t h e s t r u c t u r e s u c h a s f l a ng ng e t o p s , II-b e a m w e b , o r e d g e s .
2.
D e t e r m in in e t h e r u s t d i s t ri r i b ut u t i o n a n d t h e p e r c e n t a g e o f r u s t b y th th e fo fo ll ll o w i ng ng . a.
C h o o se se t h e r u s t d i s t ri r i b u t io io n (s ( s p o t , g e n e ra ra l , o r p i n p o i n t) t) f or o r t h e s el el e ct ct e d a re re a t h a t m o s t c lo lo s e ly ly m a t c h e s t h e co co r r e s p o n d i n g c o lo lo r o r b l a ck ck a n d w h i t e p h o t o g r a p h .
b .
Se l e ct t h e p e r c e n t a g e o f r u s t fo r t h e e va l u a t e d a r e a t h a t m o st c lose lo se l y m a t c h e s t h e c o r r e s p o n d i n g p h o t o g r a p h . R u s t s ta ta i n i n g o r d i r t w i t h t h e a p p e a r a n c e o f r u s t i s n o t t o b e i n c lu lu d e d . Ru s t u n d e r t h e co co a t i n g a n d b r o k e n b l is is t e r s w i t h a p p a r e n t r u s t a r e to to b e i n c lu lu d e d . N o n b r o k e n b l i s t er er s a re re t o b e d e f in in e d b y t h e f o ll ll o w i n g a n d i n c lu lu d e d i n t h e p e r c e n t a g e o f r u st : ( 1) 1) R u s t fi fi ll ll e d b l is is t e r ( de de t e r m i n e d b y o p e n i n g b l is is t e r ) is t o b e i n c o r p o r a t e d i n t h e p e r c e n t a g e of r u s t . ( 2) 2) F lu lu i d f i ll ll e d b l is is t e r (d (d e t e r m i n e d b y o p e n i n g b l is is t e r ) is is n o t to to b e i n c o r p o r a t e d i n t h e p e r c en t a g e of r u s t , b u t it is to b e r ec o r d e d s ep a r a t e ly .
c.
S e le le ct ct o n e c o rr r r e sp sp o n d i ng n g c o lo lo r p h o t o g r ap a p h t h a t b e s t r e p r e s e n ts t s b o t h th th e r u s t d i s tr tr i b u ti ti o n a n d t h e p e r c e n t a g e o f r u s t fo fo r t h e e v a l u a t e d a r e a .
3.
D e t er e r m i n e th t h e r u s t gr g r a d e a c co c o r d i n g t o t ab a b l e 1 of o f th t h e s t an an d a r d . F or o r ex e x a m p l e , t h e ru ru s t d i s t r ib ib u t io n a r e a w a s d e t e r m i n e d t o b e “ s p o t ,” ,” a n d t h e p e r c e n t a g e o f r u s t w a s “ g r e a t e r t h a n 0.3 0.3 per cent to 1 p ercent;” therefore, the ru st grad e is “6-S. “6-S.””
U-1
Appendix V Procedure to Determine the Presence of Soluble Lead and Insoluble Lead Chromate in Coatings A . P u rp o s e
T o d e t e r m i n e w h e t h e r t h e c o a t i n g c o n t a i n s le le a d . B.
D e sc s cri p ptt i on on
T h e p r e s e n c e o f l e a d a n d l e a d c h r o m a t e p i g m e n t e d c o a t i n g s c a n b e d e t e r m i n e d b y a c o lo lo r i n d i c a t or or u s i n g r e a g e n t s t o s w a b o v e r e x p o s e d c o a t in in g l a y e r s . Th e s w a b t e s t w i l l ve ve r i fy fy o n l y t h e p re se n c e o f lea le a d an d c hr o m a t e a n d w i ll no t p ro v id e q u a n t i t at i ve re su l t s. Th e sw a b t es t m a y al so d e t e c t t h e p r e s e n c e o f l ea ea d c h r o m a t e . C.
Eq ui u i pm p m en en t
L e a d C h e ck ck S w a b s m a n u f ac ac t u r e d b y H y b r i v e t S ys ys t e m s , I n c. c. , P O B o x 1 21 21 0 F r a m i n g h a m , Ma ssachu setts 01701; 01701; telep hon e: 800-262-5 800-262-5323. 323. D . Proc Procedu edu re for Detecting Detecting Water Water Soluble Lead Lead Pigmen ts (Lea (Lead d O xid xid e or Lea Lead d Carbonate Carbon ate))
1.
C l ea ea n an a n d r e m o v e a ll ll d u s t a nd n d d i r t fr fr o m t h e t es e s t a r e a. a.
2.
C u t a b o u t a 1 / 4 in in c h n o t c h t hr hr o u g h a l l c o a ti t in g l a y er e r s a n d e x p os o s e t h e s ub ub s t r a t e. e.
3.
A c ti ti v at a t e t he he s w a b by b y c r u sh s h i n g th t h e g l as a ss a m p u l e s m a r k ed e d “ A ” a n d “ B” B” o n t h e s w a b t u b e .
4.
W i t h th t h e p o r o u s fi f i be b e r f a ci ci ng n g d o w n , s ha ha k e a n d g e n t l y s q ue u e e z e t he he s w a b t u b e u n t i l a y e ll ll ow ow liquid is visible visible on th e swa b tip tip .
5.
R u b t h e ye y e l lo lo w i s h s w a b t i p in in t h e e xp x p o s e d c o a ti ti n g n o tc t c h fo fo r 30 30 s ec ec o nd nd s .
6.
Resul ts a.
I f t h e sw sw a b t ip ip o r t h e t es es t su su r f a ce ce t u r n s p i n k o r r e d , l e a d i s p r e s en en t .
b .
If t h e s w a b t ip o r t h e t e s t s u r f a ce d o e s n o t t u r n p in k o r r e d , l e a d is n o t p r e s e n t o r is b e lo w t h e d e t e c t io io n r a n g e o f t h e i n d i c a t o r r e a g e n t .
c.
L ea ea d c h ro ro m a t e i s n e a r ly ly i n so s o l u b l e i n w a t e r an a n d w i l l n o t i m m e d i a t el el y tu tu r n c o lo lo r . P l ac ac e t h e s w a b i n a p l as as t i c b a g a n d r e - e x a m i n e t h e s w a b a n d t h e t e s t a r e a i n a b o u t 1 8 h o u r s . I f t h e s w a b t i p o r t h e t e s t a r e a tu tu r n e d p i n k o r r e d , c h r o m a t e i s p r e s e n t .
V-1
7.
N e g a t iv i v e t es e s t r es es u l ts t s ssh h o u l d b e c o n fi f i rm rm e d b y u s in in g t h e “ Te Te s t Co C o n f ir ir m a t io io n C a r d ” t h a t is is includ ed w ith the kit. The card h as individ ual circles circles on on e face, and each circle circle contains contains a s m a l l a m o u n t o f le le a d . a.
W i t h t h e u s e d s w a b , s q u ee ee z e a d r o p o n t o r e a g e n t w i th th i n t h e t e st st ci ci r cl cl e .
b .
If p in k or r ed ap p ea r s o n th e c ir cl e, t h e n eg a ti v e t es t r es u lt is v a li d .
c.
I f p i n k o r r e d d o e s n o t a p p e a r o n t h e c ir ir c le le , t h e n e g a t iv iv e t es es t re re s u l t is is i nv n v a l i d, d, a n d a r e t e s t i s r e qu q u i r ed e d u s i n g a n e w s w a b a n d t e st st a r e a .
8.
Th e s w a b ’s ’s r ea ea g e n t s h a v e a 22- m in in u t e l if if e f r om om t h e t im im e t h e g l as as s a m p u l es es a r e b r ok ok e n , an a n d a ll ll t e s t in in g s h o u l d b e c o m p l e te te d w i t h in in t h e t i m e l i m i t . T h e s w a b i s t o b e u s e d f or or o n e t e s t a r e a only.
9.
R ed e d b l ee e e d i ng n g v er e r s us u s p in i n k - o r re r e d - co co lo lo r e d s w a b •
A r e d “ b le l e ed e d i n g ” m a y oc o c cu cu r f o r c o at at i n gs g s w i th th r e d p i gm gm e n ts t s (t (t h e co co l or or r e d ) , w h i ch ch i n c lu lu d e s re re d l e a d p r i m e r s , w h e n t e s t in in g . T h i s r e d b l e e d i n g c a n m a s k t h e p i n k o r r e d t e s t r e s u l t s a n d c a n be be m i s i n te te r p r e t e d . T h e m a n u f a ct ct u r e r r e c o m m e n d s t ha ha t o n e o f t h e f o ll ll o w i n g m e t h o d s b e u s e d t o d e t e r m i n e i f r e d p i g m e n t s , no no t l e a d , a r e b l e e d i n g f r o m t h e coating: "
C r u s h t h e c o l or or l e s s so so lu lu t i o n i n g l a s s am am p u l e “ B” B” o n l y a n d s q u e e z e a d r o p o n t o t h e s w a b t i p . S w a b t h e t e s t a r e a . I f r e d a p p e a r s , it it i n d i c a t e s b l e e d i n g i s o c cu cu r r i n g a n d t h e p r e s e n c e o f l ea ea d c a n n o t b e c o n f ir ir m e d .
"
T a k e a c o t to to n t i p d i p p e d i n v i n eg eg a r a n d s w a b t h e t es es t a r e a . I f r e d a p p e a r s , i t indicates bleeding is occurring.
•
I f t he h e c o at at in i n g i s b le l e ed e d i n g re r e d a n d l e a d i s s u s p ec e c te t e d b u t c a nn n n o t b e co c o n ffiir m e d , th th e m a n u f a ct ct u r e r r e c o m m e n d s o n e o f t h e f o ll ll o w i n g m e t h o d s t o co co n f ir ir m t h e p r e s e n c e o f le le a d : "
U s e t h e s o lu lu t i o n s f r o m a m p u l e s “ A ” a n d “ B ” a n d s q u e e z e a c o u p l e o f d r o p s o n t o a n e w t e s t a r e a . D o n o t sw sw a b . T h e f r ic ic t io io n o f sw sw a b b i n g m a y i nd nd u c e b l ee ee d i n g . If t h e s o l u t io io n t u r n s p i n k o r r e d , le le a d i s p r e s e n t .
"
U s e a s od od i u m s u l fi fi d e s o l u t i on on s u p p l i e d s e p a r a t e l y b y t h e m a n u f a c t u r e r a t a n e w t e s t area. If the test area tu rns black, lead is presen t.
V-2
Appendix W Procedure to Determine the Presence of Chromate in Coatings A . P u rp o s e
T o d e t e r m i n e w h e t h e r t h e c o a t in in g c o n t a i n s ch ch r o m a t e . B.
D e sc s cri p ptt i on on
T h e p r e s e n c e o f ch ch r o m a t e p i g m e n t e d c o a t in in g s c a n b e d e t e r m i n e d b y a c o l or or i n d i ca ca t o r u s i n g r e a g e n t s t o s w a b o v e r e x p o s e d c o a t in in g l a y e r s . T h e s w a b t e s t w i ll ll v e r i fy fy o n l y t h e p r e s e n c e o f c h r o m a t e a n d w i ll ll n o t p r o v i d e q u a n t i ta ta t i v e r e su su l t s. s. C.
Eq ui u i pm p m en en t
C h r o m a t e C h e c k S w a b s m a n u f ac ac t u r e d b y H y b r i v e t S ys ys t e m s , I n c. c. , P O B o x 1 21 21 0 F r a m i n g h a m , Ma ssachu setts 01701; 01701; telep hon e: 800 800-262 -262-532 -5323. 3. D . Proc Procedu edu re for De tect tecting ing Water Water Solub Solub le Lead Lead Priments Priments (lead or lead lead carbonate) carbonate)
1.
C l ea ea n a nd n d r em e m o v e al a ll d u s t a n d d i rt r t fr fr om o m t e st s t a r ea ea .
2.
C u t a b o u t a 1 / 4 in in c h n o t c h t hr hr o u g h a l l c o a t in in g l a y er er s a n d e x p os o s e th th e s u b s t ra ra t e .
3.
A ct c t i va v a t e th t h e s w a b by b y c r u sh s h i n g th t h e g l a ss ss a m p u l e s m a rk rk e d “ A ” a n d “ B” B” o n t h e sw sw a b t u b e .
4.
W i t h th t h e p o r o u s fi fi be b e r fa fa c in in g d o w n , sh sh a k e a n d g e n t ly ly s q u e e ze z e t h e sw sw a b t u b e u n t i l a ccll e ar ar liquid is visible on th e swa b tip tip .
5.
R u b t h e c le le a r s ol ol u t i on on o n t h e t i p i n t h e e xp x p o s e d c o a ti ti n g n o tc t c h fo fo r 30 30 s ec e c o nd nd s .
6.
Result s a.
I f t h e s w a b t i p o r th th e t e s t s u r f ac a ce t u r n s p i n k o r p u r p l e , c h ro ro m a t e i s pr pr e s e nt nt .
b .
If t h e s w a b t ip o r t h e d e t e ct io n t e s t su r f a ce d o e s n o t t u r n p in k o r p u r p le , c h r o m a t e is n o t p r e s e n t o r i s b e l o w t h e r a n g e o f t h e i nd i ca t o r r e a g e n t .
7.
N e g a t iv iv e t es e s t r es es u l ts t s ssh h o u l d b e c o n fi fi rm rm e d b y u s i n g th th e “ T e st st C on o n f i rm rm a t io io n C a r d ” t h a t is is includ ed w ith the kit. The card card h as individ u al circles circles on one face, and each circle circle contains contains a small amount of chromate. a.
W i th th t h e u s e d s w a b, b , r ub u b r e a ge g e n t w i th t h i n t h e t e st st ci ci r cl cl e .
b .
If p in k or p u r p le a p p ea r s o n th e ci r cl e, t h e n eg a ti v e t es t r es u lt is v a li d .
W -1
c.
8.
I f p i n k o r p u r p l e do d o e s n o t a p p e a r o n t h e c ir ir c le le , t h e n e g a t iv iv e t e st st r e su su l t is is in in v a l id id a n d a r e t e s t i s r e q u i r ed ed u s in in g a n e w s w a b a n d t e s t a r e a .
Th e s w a b ’s ’s r ea ea g e n t s h a v e a 11- m in in u t e l if if e f r om om t h e t im im e t h e g l as as s a m p u l es es a r e b r ok ok e n , an a n d a ll ll t e s t in in g s h o u l d b e c o m p l e te te d w i t h in in t h e t i m e l i m i t . T h e s w a b i s t o b e u s e d f or or o n e t e s t a r e a only.
W -2
Appendix X Determination of Toxic Metals in Hardened Paint A.
O bj b j ec e c t i ve ve s
1.
I d e n t if i fy t y p e o f t ox o x i c m e t a l s t h a t m a y b e i n t h e p a i n t o n e x is is t in in g i n fr fr a s tr t r u c t u r es es .
2.
D e te te r m i n e c on on c e n tr t r a t io io n o f t ox o x ic ic m e t al al in in th th e p a i n t .
3.
T h e re r e s u l ts t s o f t h e a n a l y si sis o f t h e e xi x i st st in in g p a i n t a re re r e q u i r e d b e fo fo r e t he h e p a i n t c an an b e r e m o v e d for:
B.
C.
•
P re r e d e s ig ig n sp sp e ci ci f i c a ti t i o n d a ta t a g a th th e r in in g
•
P r e m a i n t e n a n c e wo wo rk
•
W or o r k e r p r o t e c t io n
• •
P ro r o te t e ct c t io io n o f t he h e en en v ir i r on o n m e nt nt P ro r o p er e r d is is p o sa sa l o f t he h e ol ol d p a in in t
S am p l i n g
1.
T a k e p a i n t sa sa m p l e in in a b o ut u t a 22 - to t o 33- i n c h s qu qu a r e
2. 3.
M a k e s u r e t h e s am am p l e in in c lu lu d e s t h e p r i m e r ( p r i m e r c o n t ai ai n s m o st s t to t o x ic ic m e ta t a l s) s) S a m p l e in in a t le l e a st s t th th r e e lo l o ca ca t i on on s t o v e ri ri fy fy re re s u l t s
4.
P l a ce ce t h e s a m p l e s in in s e p a r a t e b ag a g s a n d l a b el e l e a ch ch b a g f o r i d e n t if i fi c at a t io io n
5.
A s u i ta ta b le l e t oo o o l f o r sa sa m p l in i n g i s a s ha ha r p e n ed ed
in c h w o o d ½- t o 1 - in
c h i se se l
L a b o ra ra t o orry T e s ti ti n g
1.
2.
T he h e p ri r i m a r y m e ta t a l s to t o t es es t f o r : •
C o b a lt lt , a s so so ci c i a t ed ed w i t h b lu lu e i sh sh a n d g r e en en i sh sh c o lo lo r s
• •
C a d m iu i u m , a s so so ccii a t ed ed w i th t h sa s a fe fe t y c o lo lo r s C h r o m i u m , a s sso o c ia ia t e d w i t h l e a d c h r o m a t e , z i nc n c ch ch r o m a t e , a n d s a fe fe t y co co lo l o r s le le a d
•
L e ad
•
Z i n c ( d e fi fi ne ne d a s a to t o x ic ic m e t a l o n l y in in t h e St St a t e o f C a l if if or or n i a )
T he h e se s e co co n d a ry r y m e t al al s to t o t es es t f o r : •
A r se n i c
•
Ba r i u m
• •
Be r y l li u m Se le n iu m
•
S i lv e r
•
Va n a d i u m
X-1
3.
R e qu qu e s t r e su su l t s in in p e r ce ce n t , b y w e i gh g h t o f m e t a l, l , an an d t o a t le l e a st st t h r e e si s i g n i fi fi ca ca n t d i g i t s. s.
4.
T y p i c a l t e s t m e t h o d s a r e E P A 6 0 10 10 B, B, E PA PA 7 42 42 0 ( le le a d s p e c if if ic ic ), ), O SH SH A 1 2 5 G m e t a l s ca ca n , IC IC P , o r p or ta b le XRF XR F i n st r u m en t f o r le a d on ly (r e q u ir es ce r ti fi e d op er a to r ).
D . Co s ts
Abou t $20 $20 to $2 $25 for for each m etal tested—red uced cost for for several metals. E.
T e s t La b o ra ra t o orri e s
•
B u r e a u of of R e cl cl a m a t io io n , Ec Ec o lo lo g i ca ca l R e s e a r c h a n d I n v e s t ig ig a t i o n (D (D - 82 82 20 20 ); ); c on on t a c t: t: C h r i s H old ren ; teleph on e: (303) 445-2178 445-2178
•
A c c re re di d i te te d L a bo bo ra ra to to ri ri es es 1.
A s s oc oc i at at i on on : A m e r i ca ca n In In d u s t ri r i al al H y g ie i e n e A s s oc oc i at at i on on ( A IH IH A )
2.
A c cr cr ed ed i t at a t io io n P ro r o g ra ra m s :
3.
•
E n v ir ir o n m e n t a l L ea ea d L a bo b o r a to to r y A cc cc r e d i ta ta t io io n P r og o g r a m (E ( E L LA LA P )
•
N a t io i o n a l L ea ea d L ab ab o r a to to r y A cc c c r e d i ta ta t io io n Pr P r o g r am a m (N ( N L LA LA P )
W eb e b s i t e A d d re r e s s : w w w . a i h a . o r g (accred (accred ited labora tories are are listed by city and State State in table format)
X-2
Mission Statements Statements
The mission of the Department of the Interior is to protect and provide access to our Nation’s natural and cultural heritage and honor our trust responsibilities to tribes.
The mission of the Bureau of Reclamation is to manage, develop, and protect water and and related resources in an environmentally environmentally sound manner in the interest of the American Public.
