The standard specifies methods for testing the checking performance of plastics, vulcanized rubber or thermal plasticity rubber in an ozone environment. The standard describes procedures for assessing the checking resistance of rubber under static or dynamic stretching conditions when exposed to air at a specific concentration of ozone, and excludes the effects of direct light. Since the ozone resistance performance of rubber is affected by ozone concentration, temperature, as well as test conditions, test results may differ from actual use. Caution is therefore required when applying test results to actual product performance. A note on the checking properties of ozone is provided in Appendix A.