This Standard specifies a method for the non-destructive measurement of coating thicknesses using beta-backscatter gauges. It applies to both metallic and non-metallic coatings on both metallic and non-metallic substrates. To employ this method, the atomic numbers or equivalent atomic numbers of the coating and the substrate need to differ by an appropriate amount.

WARNING: BETA-BACKSCATTER INSTRUMENTS USED FOR THE MEASUREMENT OF COATING THICKNESSES EMPLOY A NUMBER OF DIFFERENT RADIOACTIVE SOURCES. ALTHOUGH THE ACTIVITIES OF THESE SOURCES ARE NORMALLY VERY LOW, THEY CAN PRESENT A HAZARD TO HEALTH, IF INCORRECTLY HANDLED. THEREFORE, ALL RULES AND REGULATIONS OF LOCAL OR NATIONAL AUTHORITIES MUST BE OBSERVED.

NOTES:

1 Characteristics of isotopes used with beta-backscatter gauges are given in Appendix A.

2 The atomic numbers of some commonly used coatings and substrates are given in Appendix B.