1. Calculating Coating Lifetime Costs
Presented by:
Jayson L. Helsel, P.E.
KTA-Tator, Inc.

2. Learning Outcomes
Completion of this webinar will enable the participant to:
Define various service environments
Identify suitable coating systems for intended service
Describe a typical maintenance painting sequence
Calculate installed cost for coating systems
Perform economic analysis
Calculate coating lifetime cost

3. History
Based on “Expected Service Life and Cost Considerations for Maintenance and New Construction Protective Coating Work,” presented at NACE Corrosion 2008
Data from survey of contractors and coating manufacturers
Data presented in SSPC Painting Manual Volume 1, Good Painting Practice, Chapter 10.2, “Comparative Painting Costs”

4. Coating System Data Commonly used coating systems
For typical service environments
Service life estimates
Time until 5-10% coating breakdown
For practical maintenance sequence
Current material costs
Current shop painting costs
Current field painting costs

5. Coating Systems - Atmospheric
Most common systems for atmospheric exposure
Surface preparation requirement
Blast cleaning or hand/power tool cleaning
Minimum dry film thickness
Service environments

6. Coating Systems - Atmospheric
Service environments per ISO , “Classification of Environments”
C2: Low
C3: Medium
C5-I: Very High, Industry
C5-M: Very High, Marine

7. Coating Systems - Atmospheric
Service environment definition
C2: Low “Atmospheres with low levels of pollution; mostly rural areas”

8. Coating Systems - Atmospheric
Service environment definition
C3: Medium “Urban and industrial atmospheres, moderate sulfur dioxide pollution; coastal areas with low salinity”
“Production rooms with high humidity and some air pollution (e.g., food processing plants, laundries, breweries, dairies)”

9. Coating Systems - Atmospheric
Service environment definition
C5-I: Very High, Industry “Industrial areas with high humidity and aggressive atmosphere”

10. Coating Systems - Atmospheric
Service environment definition
C5-M: Very High, Marine “Coastal and offshore areas with high salinity”

12. Coating Systems - Immersion
Most common systems for immersion service
Surface preparation requirement
Abrasive blast cleaning
Minimum dry film thickness
Service environments

13. Coating Systems - Immersion
Service environments
Potable water
Fresh water
Salt water

15. Hot Dip Galvanizing
Service life for 4 mils minimum (American Galvanizers Association)
Mild (rural) = 68 Years
Moderate (industrial) = 33 Years
Severe (heavy industrial) = 21 Years

16. Practical Service Life
Time until 5 to 10% coating breakdown occurs (SSPC-Vis 2 Rust Grade 4)
Active rusting of the substrate is evident

17. Rust Grade 4 & 5 – General Rusting

18. Rust Grade 4 & 5 – Spot Rusting

19. Rust Grade 4 & 5 – Pinpoint Rusting

20. Typical Maintenance Painting Sequence
Original Painting
Spot Touch-Up and Repair
Maintenance Repaint
Spot prime and full overcoat
Full Repaint
Total coating removal and replacement

21. Typical Maintenance Painting Sequence
Spot Touch-Up and Repair
The first time coating repairs are made
Intended to be completed at the “Practical Life” (from Tables 1A or 1B)

22. Typical Maintenance Painting Sequence
Maintenance Repaint
Estimated to be the “Practical Life” plus 33%
e.g. “P” x 1.33

23. Typical Maintenance Painting Sequence
Full Repaint
Expected to occur at the year of “Maintenance Repaint” plus 50% of the “Practical Life”
e.g. Maintenance Repaint year + [“P” x 0.5]

24. Maintenance Painting Example
Service Environment: C3
Surface Preparation: Abrasive Blast Cleaning
Coating system: 2 coat epoxy
“P” life = 12 years
Spot touch 12 years
Maintenance 16 years
Full 22 years

25. Cost Data Current material costs Current shop painting costs
Current field painting costs

26. Cost Data Current material costs DFT Theoretical cost per sq ft
Practical spray
Practical brush/roller

27. Cost Data Current shop painting costs Surface prep cost per sq ft
Paint application cost per sq ft
Hot dip galvanizing cost
Cost multipliers
Size of job
Member size for galvanizing

28. Cost Data Current field painting costs Surface prep cost per sq ft
Paint application cost per sq ft
Cost multipliers
Size of job
Complexity of structure
Existing conditions

29. Cost Comparisons Shop vs. Field
Shop abrasive blast cleaning and priming approximately half of field cost (minimum of 250 tons of steel)

30. Cost Comparisons

31. Cost Comparisons

32. Cost Comparisons
Shop applied inorganic zinc vs. hot dipped galvanizing
75,000 to 125,000 sq ft steel
Moderate service environment (C3)
35 year structure life
4% inflation & 7% interest
Initial cost of galvanizing 43% greater
Life cycle cost for galvanizing 15% less

33. Economic Analysis Net Future Value (NFV)
How much will it cost, in inflated dollars in the year scheduled?
NFV = Current Cost [(1 + i)n]
i = inflation, n = years

34. Economic Analysis Net Present Value (NPV)
The present worth of the inflated cost (in monies today invested at current interest rates)
NPV = NFV (1/ [(1 + i)n] )
i = interest, n = years

35. Economic Analysis For each coating system:
Timing and number of painting operations
Cost of each painting operations
Carry out for projected life of structure

36. Economic Analysis Present value analysis
For each painting operation calculate:
Current cost
Net future value
Net present value

37. Present Value Analysis

38. Economic Analysis Average Equivalent Annual Cost (AEAC)
Converts entire stream of present and future costs to a present worth (NPV)
Distributes that sum in equal annual amounts over the structure’s life
Represents coating lifetime or life cycle cost
i = interest, n = structure life

39. Life Cycle Cost

40. Life Cycle Cost

41. Summary Coating system selection Material costs
Surface preparation and service environment
Determines “Practical” life
Material costs
Shop or field preparation and application
Economic analysis
Life cycle cost