This standard specifies 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 and at a definite temperature in
circumstances that exclude the effects of direct light. Great caution is
necessary in attempting to relate standard test results to service
performance since the relative ozone resistance of different rubbers can
vary markedly depending on the conditions, especially ozone
concentration and temperature. In addition, tests are carried out on thin
test pieces deformed in tension and the significance of attack for articles
in service can be quite different owing to the effects of size and of the
type and magnitude of the deformation. Explanatory notes on the nature
of ozone cracking are given in Annex A. Reference and alternative
methods for determining the ozone concentration are described in ISO
1431-3.