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

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Presentation on theme: "Calculating Coating Lifetime Costs Presented by: Jayson L. Helsel, P.E. KTA-Tator, Inc."— Presentation transcript:

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”

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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

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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

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32 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

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


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