2. Service Environment- What Coating Should I Use?
Presented by: Tom Higginbothan

3. Introduction
This webinar will discuss how the service environment, structure design, and size and location of the project can impact the type of coating system selected and specified

4. Coating System Selection Considerations
Prevailing service environment
Intended service life of structure
Type of substrate
Level of surface preparation possible
Desired service life of coating
Access to the work
Worker skills and equipment availability
Economics

5. Questions to Ask
Is the coating being applied to an interior or exterior space?
Is the coating being applied in a climate-controlled shop environment or in the field?
What is the atmospheric service environment?
What is the surface temperature during application?
What is the surface temperature once in service?

6. Questions to Ask Will the coating be exposed to abrasion and impact?
Will the coating be immersed in chemicals?
Type
Concentration pH
Temperature
Will there be a cleaning or cyclic exposure?

7. Interior Service Environment
Harder and more washable than exterior paints
Not meant to withstand sunny conditions
Can withstand the same temperature extremes as exterior paints

8. Exterior Service Environment Coatings
Designed to withstand sun, rain, snow, etc.
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

9. Atmospheric Conditions
Local prevailing air temperature
Relative humidity (moisture content in the air)
Dew point (temperature at which moisture will condense on surfaces)

10. 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) for both application and curing

11. Coatings and Moisture Not applied in rain, fog, mist, or high winds
Typically no applied when surface temperature is less than 5°F (3°C) above the dew point

12. Coatings and Moisture
Not applied to wet or damp surface unless formulated by the manufacturer for this type of application
Not applied on frosted or ice-coated surfaces

13. Coatings and Humidity
Coatings must be applied when manufacturer’s acceptable range for humidity can be met for complete curing
High humidity can cause moisture condensation and blushing and other chemical reactions when curing is inhibited
Typically below 85%
Low humidity can inhibit the cure of moisture cure coatings

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

15. Inland, Rural Free from corrosive influence of airborne salt
Polluted air and rain may still be present

16. Heavy Industrial High corrosion rates
High atmospheric chemical concentration
Sulphur dioxide, nitrous oxide, etc.

17. 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

18. Water Immersion
Moisture-resistant coatings for a mild-to-severe corrosion environment

19. 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
Boottopping area of a ships’s hull
High waterline in a tank

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

21. 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

22. Underground Buried surfaces in direct contact with soil
Possibly high acidic
Compatible with cathodic protection

23. Abrasion and Impact
Coatings exposed to particle objects that rub, scrape, impact, or erode the surface by friction
Pipeline
Dam gate

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

25. Selecting Coatings and Coating System
Long-term testing of potential systems is desirable but often impractical
Substrate type and the service environments determines most appropriate selection
User experience, accelerated laboratory testing, and data on performance in service is often compiled into qualified product lists (QPLs)

26. Selecting Generic Coating Types and Systems
Establish service environment and intended use
Review generic categories and properties
Use products by the same manufacturer when feasible
Keep in mind the generic types with the same curing mechanism work well together

27. Selecting Coating System
Example: Components for a Bridge
One coat inorganic zinc-rich (galvanic protection/permanent primer)
One or more coats of epoxy (barrier protection for steel)
One coat of aliphatic polyurethane (resistance to UV light)

28. Avoid Incompatibilities
Strong solvent in topcoat dissolving binder in primer, lifting it up and wrinkling it
Strong solvent in topcoat dissolving color in undercoat and causing it to bleed through uncured topcoat
Rigid topcoat over a flexible undercoat cracking because it could not expand and contract with undercoat

29. Reviewing Characteristics by Coating/Lining Type
Chart provides 21 common coating/lining types with 17 characteristics
Examine choices on the chart after establishing service environment and intended use

31. Coating System Selection Charts
8 charts listing generic coating systems for common service environments
Highway Bridges
Water storage tanks
Waste water treatment facilities
Power generating facilities (coal-fired plants)
Power generating facilities (nuclear power)
Pulp & paper facilities, Lock & Dam structures, chemical plants, and buried pipelines
Ships and other marine structures

32. Coating System Selection Charts
Charts found in Selecting Coatings for Industrial and Marine Structures
Example:
Replace the interior coating system on existing ground potable water storage tank in Southern Nevada
Use chart CS-2: Coating Systems for Water Storage and Tank Lining

33. Coating Systems for example:
Polyamide Epoxy (2-3 cts)
Organic zinc-rich primer/ Polyamide epoxy/ Polyamide epoxy

34. Coating System Selection
Concrete
SSPC-TU 2: Design, Installation, and Maintenance of Coating Systems for Concrete Used in Secondary Containment
SSPC-Paint 44: Liquid-Applied Organic Polymeric Coatings and Linings for Concrete Structures in Municipal Wasterwater Facilities, Performance Based
Galvanizing
SSPC-Guide: 19 Selection of Protective Coatings for Use Over Galvanized Substrates

35. Questions?