This document specifies the procedures intended for use in estimating the resistance of vulcanized or thermoplastic rubbers to cracking when exposed, under static or dynamic tensile strain, to air containing a definite concentration of ozone, at a definite temperature and, if required, at a definite relative humidity in circumstances that exclude the effects of direct light. Either visual observation or image analysis, or both, are used to evaluate the formation and growth of cracks. The changes in physical or chemical properties resulting from exposure can also be determined. Reference and alternative methods for determining the ozone concentration are described in ISO 1431-3.