The ASTM D4138-2007A (2017) standard specifies implementing procedures for the measurement of dry-film thickness of protective coating systems by the Destructiveness cross-sectional slitting method. Three procedures are included: using a grooved cutting tool (Procedure A), a ground instrument (Procedure B), and a drill bit instrument (Procedure C). Suitable for hard substrates, not for soft or ductile substrates that may deform during cutting. The measurement range is typically 2 to 2000 microns (0.1 to 80 mils), depending on the blade cutting angle. The effect of dry-film thickness on coating performance is emphasized and safety and health responsibilities for operation are noted.