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How should a contractor respond when he reads a specification requirement that "the nominal dry film thickness of the coating shall be 3 mils"?
From Roy Bradley
Laing O'Rourke
Reference to "nominal" dry film thickness (DFT) in paint specifications recognizes the fact that a variation in film thickness is inevitable. The specification should qualify "nominal" by stating that over any square meter, the average of dry film thickness measurements taken should equal or exceed the nominal thickness, and no reading should be less than, say, 80% of the nominal thickness. If this qualification is not included in the specification, then it would be prudent for the contractor to confirm and, perhaps, feel justified in suggesting, say, 70% of the nominal thickness based on an experienced assessment of the paint system's capability. Wet film thickness gauge monitoring should be an expected quality control measure.
From John Linder
Odle, Inc.
Nominal means "of or relating to" or "approximate." As stated, this would be...