Download - Relevance of Ambient Conditions
Relevance of Ambient Conditions
• Temperature/humidity restrictions often ignored
• Air and surface temperature can be too hot or too cold for proper film formation and curing
• Relative humidity can be too high for proper curing (and for moisture curing products, too low)
• Surface temperature should be at least 5°F greater than the dew point to prevent condensation (not always visible) - condensation can oxidize freshly prepared metal and effect film formation, curing, and adhesion of the film
• Acceptance criteria is found in the specification and manufacturer’s product data sheets
Inspection of Coating Materials and Mixing
• Verify complete mixing– Hand/mechanical/boxing– Thinning (within VOC
limits)– Partial kits– Pot life
• Confirm that the correct coatings and colors are applied – can be very complicated when many substrates involved
Coating Application Inspection – Pay Special Attention to Limited
Access/Stripe Coats
Coating Application Inspection – Verify Back Rolling and Back
Brushing
Coating Application Inspection Number of Coats
• Verify correct number of coats applied
• Monitor drying time between coats
• Verify cleanliness between costs
Verify Complete Coverage, but Avoid too Much
Coating
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Coating Application Inspection - Monitor Wet
Film Thickness
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Measure Dry Film Thickness (DFT) Non-Destructive Tests
• Ultrasonic gage can measure DFT on Concrete (ASTM D6132). SSPC-PA9, number of measurements, test locations, interpretation of results.
• Magnetic gages are used to measure DFT on steel substrates (ASTM D7091)
• Eddy current gages are used to measure DFT on non-ferrous metal substrates (ASTM D7091)
• SSPC-PA2, Number of measurements, test locations, interpretations of results
Trouble shooting - Destructive DFT Measurements
• Destructive tests can measure the thickness of individual coats as well as total system thickness (ASTM D4138)
Inspect Joints and Sealants
• Improperly sealedjoints allow for waterintrusion
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Inspection Summary
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INSPECTION CATEGORY INSPECTION VERIFICATION
Surface Preparation — Equipment Specified equipment/methods used
Surface Preparation — Metallic Substrates Cleanliness per specification and industry standards
Surface profile per specification
Surface Preparation — Concrete Substrates Cleanliness per specification
Satisfactory moisture content, pH
Surface Preparation — Existing Coating Removal of loose/poorly adherent coating
Removal of grease, oil, chalk, dust, dirt
Ambient Conditions Air and surface temp, RH, dew point per specification
Coating Materials and Mixing Proper coating materials and colors applied
Coatings thoroughly mixed; thinned as required
Multiple component coatings used within pot life
Application Specified application methods used
Surfaces clean between coats
Back rolling and back brushing done as specified
Stripe coats applied as specified
Complete coverage achieved
Correct number of coats applied
Ample drying time between coats
Correct thickness applied (wet)
Correct thickness applied (dry)
Film continuity (runs, pinholes, gloss, etc.) per spec
Inspection of Commercial and Architectural Cleaning and
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