1. WALTER SCARBOROUGH CSI CCS CCCA SCIP AIA wscarborough@hbig.us 214.491.7385 D+D Specifiers Series Sponsored by Exterior Steel and High-Performance Coatings

2. To identify the properties of a coating and to discuss the most common coating system typically used for ferrous metals at the exterior of buildings Webinar Intentions

3. Basics

4. Why Coat Steel? Protection Aesthetics

5. Basics of Rust Steel + Oxygen + Moisture RUST

6. Mechanism of Protection Barrier to protect steel from effects of its environment Inhibitive by controlling the rate of corrosion Sacrificial by deteriorating before the steel

7. Properties of a Coating

8. Chemical resistance Low moisture permeability Ease of application Adhesion Cohesive strength

9. Properties of a Coating Tensile strength Flexibility Impact resistance Abrasion resistance Temperature resistance

10. Properties of a Coating Cold flow resistance Dielectric strength Surface tolerant VOC compliant Low odor

11. Selection of a Coating

12. Type of exposure Operating conditions Substrate Application ambient conditions Environmental regulations

13. Selection of a Coating Budget During operation or shutdown Time constraints New construction or maintenance Shop or field application

14. Selection of a Coating Design or fabrication considerations -Inaccessible areas -Bolted connections -Dissimilar materials -Imperfections (welds, laminations, and gouges) -Sharp corners

15. Typical Exterior System

16. One of the longest lasting systems includes following: Primer: Zinc-Rich Intermediate Coat: Epoxy Top Coat: Polyurethane

17. Binder, or resin, that is highly loaded with a metallic zinc-dust pigment Binder holds zinc particles in contact with steel substrate to create a galvanic cell (zinc will deteriorate before steel) Provides anticorrosion (galvanic) protection for as long as 20 years or longer Zinc-Rich Coatings

18. Requires clean steel substrates Best method of application is in the fabrication shop Zinc-Rich Coatings

19. Exceptional adhesion strength Resistant to solvents and chemicals Water-borne and high-solids are dominant technologies in use Epoxy Coatings

20. Have a fatal flaw - not UV light stable and thus requires a top coat Epoxy Coatings

21. One of most versatile coatings available Chemical and solvent resistant Best color and gloss retention Light stable Abrasion resistant Long lasting Polyurethane Coatings

22. Acrylic polyurethanes are good for aesthetics Polyester polyurethanes are good for chemical resistance, but weather resistance not as good Polyurethane Coatings

23. Zinc-rich protects the steel by becoming sacrificial coating Epoxy protects the zinc-rich Polyurethane protects the epoxy and provides color Purpose of Coatings

24. Shop or Field Applied

25. Shop coating steel is always far better than field applying a coating Shop or Field Applied

26. Cost is lower than field coating Shop or Field Applied

27. Safer for workers because there is not a large force of painters up in the air Shop or Field Applied

28. Short pot life of multi-component coatings is a logistical challenge when field coating Shop or Field Applied

29. Reduced construction time Shop or Field Applied

30. More efficient use of resources Less labor Blasting media is recycled Shop or Field Applied

31. Controlled application conditions Shop or Field Applied

32. Field Considerations

33. Bolted connections require special attention Field Considerations

34. Bolted connections in the lay-up-yard Field Considerations

35. Bolted connections up in the air Field Considerations

36. For quality control purposes, good if manufacturer can conduct field training classes for touch-up work Field Considerations

37. Imperfection and damage touch-up Field Considerations

38. Peeling paint due to overlap of primer at interior corners of H- sections Field Considerations

39. Coating does not cover weld splatter Field Considerations

40. Spot rusting due to proximity of paint booth and blasting area Field Considerations

41. Coating selection should be based factors that are important to the application Zinc-rich, epoxy, and polyurethane is high quality coating system that is useful for architectural applications Shop coating will always be better than field coating Conclusions

42. D+D Specifiers Series Sponsored by Questions WALTER SCARBOROUGH CSI CCS CCCA SCIP AIA wscarborough@hbig.us 214.491.7385