This standard specifies procedures for external exposure testing of coatings on metal substrates, including new and rusting steels. Tests are used to assess the performance of coatings under a variety of environment conditions, including solar radiation, Humidity and temperature changes. Exposure under multiple climate conditions is recommended to obtain representative durability data due to differences in environmental factors. A single exposure test cannot predict long-term degradation of materials and reliable data need to be obtained through long-term repeability testing. The standard also indicates the variables to be considered in testing and provides guidance on aging testing.