1. Presented by: Tony Serdenes, Greenman-Pedersen
Maintenance Coating- Spot Repair and Primer as an Alternative to Full Coating Removal
Presented by: 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 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 Coating B 1604 X 0.42 X 0.74 / 2 = 252.63 square feet
$30 / = $0.119 per square feet
Coating B
1604 X 0.56 X 0.75 / 2 = square feet
$35 / = $ 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.