Procedure for Determining Conformance to Dry Coating Thickness Requirements

This standard describes a procedure for determining shop or field conformance to a specified coating dry film thickness (DFT) range on ferrous and non-ferrous metal substrates using two types of nondestructive coating thickness gages (Type I, magnetic pull-off; and Type 2, electronic) described in ASTM D7091.¹

This standard defines a procedure to determine whether coatings conform to the minimum and the maximum thickness specified. See Note 12.1 for an example of a possible modification when measuring dry film thickness on overcoated surfaces.

This document contains the following non-mandatory appendices:

• Appendix 1 - Numerical Example of Average Thickness Measurement and Illustration of the Procedure for Determining the Magnitude of a Nonconforming Area

• Appendix 2 - Methods for Measuring Dry Film Thickness on Steel Beams (Girders)

• Appendix 3 - Methods for Measuring Dry Film Thickness for a Laydown of Beams, Structural Steel, and Miscellaneous Parts after Shop Coating

• Appendix 4 - Method for Measuring Dry Film Thickness on Coated Steel Test Panels

• Appendix 5 - Method for Measuring Dry Film Thickness of Thin Coatings on Coated Steel Test Panels that Have Been Abrasive Blast Cleaned

• Appendix 6 – Method for Measuring the Dry Film Thickness of Coatings on Edges

• Appendix 7 – Method for Measuring Dry Film Thickness on Coated Steel Pipe Exterior

• Appendix 8 – Examples of the Adjustment of Type 2 Gages Using Shims

• Appendix 9 – Precaution Regarding Use of the Standard for Coating Failure Investigations

• Appendix 10 -- Procedure for Obtaining a Greater Population of Thickness Measurements Using Type 2 Gage Continuous Read/Scanning Probe Technology

Units of Measure: This standard makes use of both the ASTM SI 10, “American National Standard for Metric Practice” International System Units (SI) and U.S. Customary units. The measurements are not exact equivalents; therefore, each system must be used independently of the other.