This standard applies to radiation gauging devices, commonly called devices, that use sealed radioactive sources or machinegenerated sources for the determination or control of thickness, density, level, interface location, particle size distribution, or qualitative or quantitative chemical composition. The standard establishes a system for classification of the gauging devices based on performance specifications relating to radiation safety. In addition to specific tests for use conditions and accident conditions (fire), guidelines for other safety features and considerations are presented. This standard does not apply to the measurement performance of gauging devices.