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More than Just Paint
Charles Kucherka, P.E.June 25, 2015
TEXAS PUBLIC WORKS ASSOCIATIONAUSTIN, TEXAS
Pre‐Design
• TCEQ Annual Reports• Active Engineering• Experienced Inspector• Looking for:
– Regulatory Requirements– Structural Condition– Capacity of Appurtenances– Existing Coatings– Site Challenges
Pre‐Design – Regulatory Requirements
• TCEQ or State Agency– Is Rehab. Maintenance?
• AWWA• OSHA?
– Ladders – Hatches– Confined Space Entry
Pre‐Design –Structural Condition and Capacities
• Structural Condition• Capacities
– Vents– Overflows
Pre‐Design ‐ Soils and Coatings with Heavy Metals
• Lead, Cadmium and Chromium• Lead
– 5,000 PPM or 0.5% by weight– OSHA 1926.62 “Lead”
• Paint– Total Lead– TCLP Test
• Soils – SPLP Test• Sampling Plan
– Prevailing Winds– Drainage Patterns– Manways
Pre‐Design – Site and Construction Challenges
• Space for Construction• Surrounding Structures• OHE• Pump Stations & Facilities
Coating & Rehab Specifications – The Basics
• Choose Your Words Wisely• If you want it, specify it• Reference Standards Specifically• Meetings and Schedules• Inspection• Owner Standardization
Design Specifications ‐ Coatings
• AWWA D102 “Standard for Coating Steel Water‐Storage Tanks” • Interior & Exterior Systems• Best?
– Project Goals– Budget?
• Coating Manufacturers• Specify:
– Coating by Name and Manufacturer– Minimum & Maximum Mils per Coat– Color (contrasting)
• Logos
Design Specifications – Surface Preparation
• How “clean” the steel is…• Typical for Rehabs
– NACE No. 2/SSPC‐SP 10, Near‐White Metal Blast Cleaning– NACE No. 3/SSPC‐SP 6, Commercial Blast Cleaning– SSPC‐SP 3, Power Tool Cleaning
• Weld Preparation• Abrasives
Specifications – Containment/Dehumidification
• SSPC Technology Guide 6 “Guide for Containing Surface Prepartion Debris Generated During Paint Removal Operations”
• TCEQ 30 TAC Chapter 111.131‐139 “Abrasive Blasting of Water Storage Tanks Performed by Portable Operations”
• Job Specific and Must be Specified• Ventilation• Dehumidification
Construction‐ Soils and Coatings with Heavy Metals
• SSPC Technology Update No. 7 – Sampling During Construction• Sampling• Protection During Construction• Post Construction
– SSPC Technology Guide No. 7 – Disposal– Chain of Custody
Bid Form – Expect the Unexpected
• Supplementary Items– Rafter Replacement– Floor Plate Replacement– Grinding– Pit Filling– Seam Welding– Misc. Steel (ton)
Design – Away from Corrosion
• Avoid– Skip Welding– Inaccessible or hard to reach areas– Gaps– Overlaps (roof plates)– Angles– Dissimilar Metals
• API 653 – Tank Insp., Repair…
Design – Cathodic Protection
• AWWA Standard D104• NACE SP0388 – Cathodic Protection for Water Storage Tanks• Coordinate with Owner• Performance Specification
Construction – Inspection
• Small Things Big Problems• Coatings failures and the corrosion that follows can:
– Cost money…..a lot of it. – Cause structural failures – Accelerate maintenance schedules
• Special Training ‐ NACE Coating Inspector Program• How Often
– Resident Representation– Hold‐Point Inspection
Construction – Inspection ‐ Environmental Testing
• Inspector should be checking:– No. 1 and No. 2 ‐ Substrate Surface & Ambient Air Temperature– Relative Humidity & Dew Point– Wind Speed– Sound Level Meter?
• How Often?• Tools
– Thermometer (Infrared or Magnetic)– Digital Hydrometer or Sling Psychrometer– Wind Speed Monitor– Digital Sound Level Meter
Construction – Inspection – Surface Prep. and Profile
• Inspector should be checking:– Prepared steel per SSPC/NACE level specified– Anchor Profile– Weld Preparation– Steel Conditions
• Tools– SSPC‐VIS 1 “Dry Abrasive Blast Cleaning”– SSPC‐VIS 3 “Hand and Power Tool Cleaning”– NACE SP0178 “Plastic Weld Comparator”– Replica Tape or Digital Profile Gauge
Construction – Inspection – Coating Application
• Weather and Changes• Temperature • Coatings and Thinners• Environmental Controls• Application Method• Inspector should be:
– Verifying coatings– Documenting lot numbers– Verifying wet mils
• Tools– Wet Film Thickness Gauge– Dry Film Thickness Gauge
Construction – Inspection – Final
• SSPC‐PA 2 Measurement of Dry Coating Thickness with Magnetic Gages
• Total Dry Film Thickness• Inspector should:
– Document Holidays– Document Mil Readings
• Tools– Dry Film Thickness Gauge– Holiday Tester
• Cathodic Protection