1. Specifying and Selecting Coatings Presented by: Troy Fraebel, Sherwin Williams

2. Introduction
This webinar will provide guidance on how to properly specify and select a coating system for a specific substrate (carbon steel, other metals, concrete, previously coated), structure, and environment.

3. Painting Project Specification
A statement of particulars, describing the dimensions, details, or peculiarities of any work to be undertaken..
Legal document.
Part of a contract.
Provides the (technical) rules.
Practical document.
Requires thorough planning.
What, where, when,
but NOT so much on how!

4. Painting Project Specification Contents
Scope of work.
Areas to be coated and not coated.
Site specific requirements.
Paint materials and suppliers.
Surface preparation, application, and inspection requirements using standard methods.

5. Specification Writing Goals
Clear.
Complete.
Concise.
Consistent.
Correct.

6. Specification Writing Techniques
Use short sentences.
One requirement per sentence.
Place action words at the beginning.
Use strong verbs.
Never repeat descriptions or requirements.
Define words that may be misunderstood.
Use the same writing style throughout.

7. Important Word Meanings
Shall. Essential requirement.
Should. Preference or strong recommendation.
May. Used when alternatives are acceptable.

8. Coating Specification Formats
Construction Specification Institute (CSI)
SSPC modified CSI format
Major Sections
General
Products
Execution

9. Coating System Selection
Coating mechanisms and types
Type of substrate (steel, concrete, etc.)
Prevailing service environment (immersion?)
Level of surface preparation possible
Access to the work
Owner’s desires and expectations:
Intended service life of structure
Desired service life of coating
Worker skills and equipment availability
Aesthetics (gloss & color retention)
Timing
Economics
Establish service environment and intended use.
Use products by the same manufacturer when feasible.
Keep in mind that generic types with the same curing mechanism work well together.

10. Making Steel Corrode Anode Cathode Metallic Pathway Electrolyte
Steel is made from iron ore using huge amounts of thermal energy

11. How Coatings Protect Surfaces
Barrier
Inhibitive
Sacrificial
Corrosion Prevention
Stop the deterioration of a substrate. Corrosion is a natural process that displays the tendency of materials to “give up” energy and return to its natural state.

12. Zinc-Rich Primers
Contain High Percentage of Zinc Dust in the Dried Film So That There Is Direct Contact Between Zinc Particles and Steel
Sacrificial / Galvanic Protection (like galvanizing)
Corrosion Protection Prevention of Undercutting

13. Solvent Based Epoxies Excellent Alkali, Solvent, and Water Resistance
Good Abrasion Resistance
Good Acid Resistance
Good Exterior Durability but ...
Low Temperature Application Available
Typical Dry Heat Resistance to 250° F

14. Solvent Based Alkyds Single Package / Ease of Application
Application as low as 40°F
Single Package / Ease of Application
Heat Resistance to  F
Embrittle With Age
Prone to Yellow / Saponify
Require modification for exterior topcoats

15. Waterborne Acrylics Single Component Water Based
Fast dry and fast re-coat
Good color and gloss retention
Primers must contain inhibitors
Low stress

16. Polyurethanes / Polyureas / Polyaspartics
Aliphatic
Excellent Color Retention
Excellent Gloss Retention
Primarily Used as Finish Coats
More Expensive than Aromatics
Aromatic
Yellows & Chalks in Sunlight
Yellows & Chalks in Bright Artificial Light
Used as Primers & Intermediate Coat
Less Expensive than Aliphatics

17. Moisture Cured Urethanes
Can be surface tolerant
Can be applied during high humidity
Easy to application
Fast cure / fast recoat
Low temperature application to 20 F.
Single component
Reinforce with micaceous iron oxide
Aliphatic topcoats

18. Types of Substrates Coated

19. Types of Steel
Cold-rolled
Hot-rolled
Stainless steel

20. Cold-Rolled Steel Typically steel coils; typically thin sheet steel.
Produces a denser, smoother surface than hot-rolling.
Phosphating may be used to promote coating adhesion; otherwise coatings may not bond well.

21. Hot-Rolled Steel Typical of structural steel used in construction.
Manufacturing process creates a bonded layer of iron oxide called mill scale.
Smooth
Cathodic
Differential expansion
Mill scale is smooth, cathodic to carbon steel, and different coefficient of thermal expansion.

23. Stainless Steel
Better mechanical properties and greater resistance to corrosion than mild steel.
Numerous grades of stainless steel
(add chromium and )
Harder than mild steel
Prone to stress corrosion cracking (SCC)
chlorides at temperatures above 50 °C

24. Hot Dip Galvanized Surfaces
Application of a zinc coating to steel by dipping it in molten zinc or by depositing zinc on the steel through electrolytic means.
Post-treated with oil or a chromate conversion coating to protect from white rust, a wet-storage stain.
Post-treatments must be removed before coating.
Alkaline substrate.
Oil-based alkyds
may saponify.

25. Aluminum
May require chemical treatment, wash priming, and/or brush off blasting with a soft abrasive.
SSPC-SP 16

26. Ductile Iron Use Standard NAPF 500-03
“Applying steel surface preparation specifications to ductile iron is inappropriate, and may actually result in damage to the pipe surface with subsequent reduced coating effectiveness and life expectancy.”
National Association of Pipe Fabricators, Inc.

27. Concrete
A composite material comprised of a Portland cement and water mixture that serves as a binder for embedded particles of coarse and fine aggregate.

28. Concrete Characteristics
Alkalinity (pH range of 9 to 12)
Porosity
Moisture
Movement of concrete (i.e., cracking)
Small interconnected voids that liquid and gases can penetrate.

29. Concrete Types and Finishes
Concrete (tilt-up, cast-in-place, block)
Finish (broom, steel trowel, sacked, stoned, wood floated)
Curing compounds / Sealers (paintable?)

30. Other Substrates
Wood or plywood
Polyvinyl Chloride (PVC)
Fiberglass Reinforced Plastic (FRP)

31. Demands of Environments on Coating Systems

32. Questions to Ask
Is the coating being applied to an interior or exterior space?
What is the atmospheric service environment?
Will the coating be exposed to abrasion and impact?
What is the surface temperature once in service?
Will there be a cleaning or cyclic exposure?

33. Questions to Ask Will the coating be immersed in chemicals? Type
Concentration pH
Temperature
Primary or secondary containment
What are the application conditions?
Is the coating being applied in a climate-controlled shop environment or in the field?
What is the surface temperature during application?

34. Interior Service Environment Coatings
Coatings need not withstand sunny conditions.
Maybe climate controlled.

35. Exterior Service Environment Coatings
Designed to withstand sun, rain, and snow.
Remain flexible after curing; won’t crack or peel as it expands and contracts with changes in temperature and humidity.
Additives enhance mildew-, fungus-, and UV-resistance.

36. Service Locations What are some different service locations?
How might location affect the type of coating you would select?
What factors should be considered?

37. Inland, Rural
Free from the corrosive influence of airborne salt; polluted air and rain may still be present.

38. Heavy Industrial High corrosion rates
High atmospheric chemical concentration (i.e., sulphur dioxide, nitrous oxide)

39. Marine High concentration of salt mist (chlorides).
Not always in direct contact with salt spray or splashing waves.
Often in conjunction with heavy industrial environments.

40. Immersion Better surface preparation. More impermeable.
Typically not UV stable.
Must resist constant exposure to the cargo.

41. Alternating Immersion
Any area in which immersion in water is combined with period of exposure to the atmosphere just above it.
Steel in a tidal range.
High waterline in a tank.

42. Condensing Humidity Service
Example:
Headspace in a tank
Indoor pool with condensation on ceiling
Cold pipes
Note: Very aggressive due to purity of water.

43. Chemical Environments
Strong concentrations of highly corrosive gases, fumes, and chemicals that come in direct contact with the coated surface.
Mild to severe; direct immersion or splash.

44. Underground Buried surfaces in direct contact with soil.
Possibly highly acidic.
Compatible with cathodic protection.

45. Abrasion and Impact
Coatings exposed to particle objects that rub, scrape, impact, or erode the surface by friction (i.e., pipeline, dam gate).

46. Final Service Temperature
Certain coatings are prone to limited chemical resistance and early failure when exposed to high in-service temperatures.

47. Other Factors to Consider
What else might impact your choice of coating selection beyond the service environment?

48. Application Temperature
Apply coating system only when the air and substrate temperature are within the range indicated by the manufacturer’s written instructions on the product data sheet (PDS).

49. Coatings and Moisture
Not applied to wet or damp surfaces unless formulated by the manufacturer for this type of application.
Not applied on frosted or ice-coated surfaces.
Typically not applied when surface temperature is less than 5oF (3oC) above the dew point.

50. Previously Coated Substrates
Generic Type
Assessment of Current Paint
Percentage (%) of corrosion
Adhesion to substrate and other coats
Thickness (DFT)
Number of coats
Chalking, blistering, etc.
Test Patch!

51. Adhesion
Test adhesion of existing coating to itself and to the substrate.
Low adhesion values can indicate possible delamination during overcoating.

52. Multiple Coating Layers
High internal stress possible.
Can cause delamination and reduce intercoat adhesion when overcoated.
Delaminated and cracked coatings are not good candidates for overcoating.

53. Chalking and Erosion
Typical of aging epoxy and alkyd coatings.

54. Coating Compatabilty Small field patch tests.
Apply proposed repair system to small deteriorated areas using same surface treatment planned for repairs.
Visual defects and adhesion testing can detect incompatibilities.

55. Coating Compatabilty
Patch tests are described in ASTM D5064 Standard Practice for Conducting a Patch Test to Assess Coating Compatibility and SSPC-Guide 9 Guide for Atmospheric Testing of Coatings in the Field.

56. Coating System/Structure Life Expectancy
Expected service life of structure and coating or overcoat system.
Economics of overcoating versus remaining years of service life.

57. Site-Specific Concerns
Noise and emission considerations.
Permissible surface preparation and application methods that meet all requirements and are suitable for the coating product selected.
Return to service time.
Use of properly trained applicators (SSPC CAS, C12, Marine Plural Component, etc.).

58. Budget and Time Constraints
Some examples:
An aliphatic polyurea cures faster than an acrylic, a good selection when turnaround time is short and resistance to sunlight is desirable.
An epoxy is less expensive than a polyurethane and works just as well in interior environments.

59. Summary
A coating system is applied to a structure to prevent corrosion and perhaps impart color and gloss. Each layer (primer, intermediate coat, and/or topcoat) provides a specific protective function.
There are a variety of substrates that are protected using coatings and coating systems. The various substrates have inherent characteristics that impact the degree of surface preparation and coating system selection.
A review of coating types available, substrates, service environment, the condition of the existing coating system if any, and budget and time constraints are the means by which the proper coating system can be selected to provide the maximum corrosion protection.

60. ???????ANY QUESTIONS ????????