This Standard provides practical test methods for the on-site determination of the range of thicknesses and the mean dry film thickness of a protective coating system, or its component coats, upon a metallic structure or fabrication.The coated fabrications to which the method may be applied include tanks or reservoirs, bridge girders, equipment used in processing chemicals or petroleum, pipelines, and fabricated articles such as vehicles, white goods and other items of industrial production, where there is lack of uniformity of substrate thickness, metallographic character, surface condition and the film of the protective coating.NOTES:1 Appendix A provides a laboratory test method for the microscopic determination of the thickness of the film adhering to a substrate. This method would only be used where no other method is acceptable.2 Appendix B provides a method for determining the thickness of a flake of the coating using an optical microscope.3 ISO 2808 provides information on additional methods of determining film thickness.