Presented by: Tony Serdenes, Greenman-Pedersen

1. Maintenance Coating- Spot Repair and Primer as an Alternative to Full Coating Removal Presentedby: Tony Serdenes, Greenman-Pedersen

2. Learning Outcomes • At the end of this webinar, you will be able to: • Recognize the proper steps to take when developing a maintenance coating plan • Determine when to perform spot repair, spot repair and overcoating or complete recoat of structure

3. Introduction The webinar will define maintenance painting and explain the differences between repairing by overcoating versus full coating removal and recoat. Overcoating is generally defined as the practice of painting over an existing coating as a means of extending its useful service life. Overcoating may be a cost-effective alternative to complete coating removal and repainting.

4. Major Steps in Maintenance Coating • Six major steps in a maintenance coating program: Step 1: Plan and conduct condition assessment survey Step 2: List potential maintenance painting options Step 3: Select appropriate maintenance painting options Step 4: Establish implementation procedures Step 5: Implement maintenance painting options Step 6: Plan and implement follow-up activities

5. Step 1 • Used for several purposes: • To determine the need for recoating • To determine the extent of corrosion and corrosion damage • To determine the performance of various coating systems • To prioritize coating requirements where insufficient funds are available to do all the desired work

6. Step 1 • Three types of surveys: • General Overview • Detailed Visual Survey • Physical Coating/Structural Inspection

7. General Overview • During a general coating condition assessment: • Only one or two parameters are rated (e.g., general condition or rusting) • Structure normally observed from the ground • A qualitative rating • Done in a few hours or less

8. Detailed Visual Survey • During a detailed visual assessment: • Relies exclusively on visual observations • Numerous structural elements are separately rated according to SSPC-VIS 2, ASTM D610 or equivalent • Obtain a semi-quantitative rating of the percent of surface deteriorated • May be used to develop preliminary cost estimates for recoating

9. Examples of Pictorial Guides

10. Physical Inspection Physical testing is required to determine whether the coating can be overcoated or repaired, or whether it is too weak to accept another coating layer

11. Physical Inspection • A physical inspection of the structure and aged coating system should be conducted to determine: • Film thickness • Number of layers of paint • Adhesion • Underlying substrate condition • Coating type • Presence of soluble salt contamination

12. Physical Inspection SSPC TU-3, Overcoating provides discussion of the value of physical testing, as well as the procedures for testing Table 1 in Appendix A.1 contains a table assessing the risk of overcoating based on film thickness and adhesion of the existing coating

13. SSPC TU-3, Table 1

14. Structural Inspection • Coating assessment should be included as part of any general structural inspection for loss of: • Metal • Broken joints

15. Structural Inspection Evaluate and record the ratings of individual structures or structural elements Create a sub unit sampling plan, identifying the portions of the structure or facility that will be rated and the type of rating scheme to be used

16. Step 2 • List potential maintenance painting options: • Spot repair only • Spot repair and overcoating • Complete recoat of structure

17. Spot Repair Only • Surface preparation and touch-up coating of localized areas of deteriorated coating and corrosion • Primarily a “stop-gap” method • Re-evaluate within 3 to 5 years

18. Spot Repair Only • Reasons why spot repair may be selected are: • Repair are hidden or in a low-visibility area • Corrosion and degradation are limited to isolated areas • Less than 1% of total area

19. Spot Repair And Overcoating Involves spot repair of deteriorated coating and corroded areas followed by the application of a full finish coating over the entire surface, including spot repaired areas and intact coating areas Expected to give 5 years or more additional life

20. Complete Recoat of Structure When corrosion and deterioration exceed 16% of the total area

21. Determining Maintenance Painting Options

22. Step 3 Evaluate economics of available options The variables involved in protective coatings often require a variety of solutions, each of which will carry unique cost-benefit factors

23. Step 3 • Economic Analysis • Initial Vs. Service Life Costs • Initial Cost Factors • Time Value of Money • Analysis

24. Step 3 • Initial cost factors are: • Mobilization/Demobilization • Access • Preparation • Material Costs • Container Vs. Coverage • Service life of coatings • Initial Vs. Service life per square foot

25. Step 3 • Example of Container Vs. Coverage Calculation • Urethane finish @ 2 mils • Coating A at $30 per gallon and 42% volume solids • Coating B at $35 per gallon and 56% volume solids

26. Step 3 Calculate coverage and assume 20% loss factor: 1604 X % Volume Solids X (1- Loss Factor) / DFT Cost analysis of paint material should be based on coverage cost NOT cost per gallon

27. Step 3 • Coating A • 1604 X 0.42 X 0.74 / 2 = 252.63 square feet • $30 / 252.663 = $0.119 per square feet • Coating B • 1604 X 0.56 X 0.75 / 2 = 336.84 square feet • $35 / 336.84 = $0.1039 per square feet

28. Step 3 • Initial cost factors • Surface preparation • Application • Equipment • Curing / drying • Interference / downtime • Environmental / health / safety • Indirect

29. Step 3 • Net Present Value • The value today of a future payment or series of payments discounted at the appropriate discount rate • Discounting • The process of finding the present value of a payment or series of future cash flows; the reverse of compounding • Net Future Value • The amount to which a payment or series of payments will grow over a given future time period when compounded at a given interest rate • Compounding • The arithmetic process of determining the final value of a payment or series of payment when compound interest is applied

30. Step 3 • Economic Analysis • Projected life of structure • Consider systems • Original painting • Touch-up (Spot/Spot) • Touch-up (Spot/Full) • Full repainting • Cost calculations • Current cost levels • Net future levels • Net present levels • Average equivalent annual cost

31. Step 4 • Select appropriate maintenance painting options and establish implementation procedures • Identify relevant factors for coating system selection • Select surface preparation methods and coating materials • Prepare specification

32. Identify Relevant Factors for Coating System Selection • Coating system selection is influenced by special factors such as: • Environmental, health and safety regulations • Budgets • Exposure environments • Weather • Configuration of structure • Surface contaminants

33. Select Surface Preparation Method Solvent cleaning Hand and power tool cleaning Abrasive blast cleaning Wet abrasive blast cleaning Waterjetting

34. Select Coating Materials • The selection of the coating system involves two phases: • Identify the generic types • Identify the criteria for selecting materials

35. Prepare Specification Provides a complete description of the desired work by prescribing specific procedures, processes and materials Provides criteria for acceptance or rejection of work

36. Step 5 • Implement maintenance painting options • Clean and coat the structure

37. Step 6 • Plan and implement follow-up activities: • Establish need for periodic inspection • Establish schedules for condition assessment • Ensure proper documentation and filing of historical information • Institute preventative maintenance measures

38. Establish Need For Periodic Inspection Inspection should be made of the structure within 6 to 12 months after application

39. Establish Schedules For Condition Assessment First condition assessment would normally be conducted about 5 years after the original application and every 3 years thereafter

40. Ensure Proper Documentation And Filing Of Historical Information Records of the daily inspection logs and coatings should be stored in owners files Retained coating samples should be properly labeled and stored for at least 3 years

41. Institute Preventative Maintenance Regular removal of contaminants

42. Summary Following a maintenance coating program enables the coating to perform its expected life and avoid early coating failure. At times when repair of the coating is needed an evaluation of the condition of the coating shall be performed to aid in determining the method of repair. Often spot repair or spot repair and overcoating is an economical alternative to full removal and recoat.