The standard specifies the basic principles and operating procedures for exposure testing of Non-metallic materials using a closed carbon arc instrument. This equipment simulates the efflorescence effect of material exposure to sunlight and moisture, such as rain or dew, in actual use. The standard covers procedures for acquisition, measurement and control of exposure conditions, but does not specify exposure conditions appropriate for a particular material. Test samples should be carried out in a controlled environment, and the standard also provides general guidance on specimen preparation and evaluation of results. The standard replaces the previous G23 procedure and emphasizes requirements for safe operation, including ozone treatment.