1.1 This test method covers the use of X-ray fluorescence (XRF) for determining the coating weight (mass) of metallic coatings on steel sheet. The test method is intended to be used for " on-line " measurements of coating on continuous production lines. 1.2 This test method is applicable to the coatings covered by the following ASTM specifications: A599/A599M , A623 , A623M , A653/A653M , A792/A792M , A875/A875M , A879/A879M , A918 , A924/A924M , A1046/A1046M , and A1063/A1063M . It may be applicable to other coatings, providing that the elemental nature of the coating and substrate are compatible with the technical aspects of XRF such as the absorption coefficient of the system, primary radiation, fluorescent radiation, type of detection. 1.3 This test method includes the procedure for developing a single standard determination of coating weight (mass). 1.4 This test method includes procedures for both X-ray tube and isotope coating weight (mass) measuring instruments. 1.5 The values stated in either inch-pound units or SI units are to be regarded separately as standard. Within the text, the SI units are shown in brackets. The values stated in each system are not exact equivalents; therefore, each system shall be used independently of the other. Combining values from the two systems may result in nonconformance with the specification. 1.6 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.