scope:

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 1, 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 11.1 for an example of a possible modification when measuring dry film thickness on overcoated surfaces.

This document contains the following non-mandatory appendices. Appendices 2, 3, 4, 5, 6, 7, 10, and 11 become mandatory when invoked by the project specification or if the contractor or laboratory has agreed in writing to comply with their provisions.

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 on Plate, Beams, and Pipe Spools Using Type 2 Gage Continuous Read/Scanning Technology

Appendix 11 Method for Measuring the Thickness of Intumescent (Fireproofing) Coatings Applied to Load-Bearing Structural Steel Members, Fire Divisions, Pipework, and Vessels/Tanks

Units of Measure:

This standard makes use of both the ASTM SI 10 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. Also, a tilde (~) is used to indicate approximation.