This International Standard is intended for use in estimating the resistance of vulcanized rubbers to cracking when exposed, under static tensile strain, to air containing a definite concen tration of ozone and at a definite temperature in circumstances where the effects of direct light are excluded.
Great caution is necessary in attempting to relate standard test results to service performance since the relative ozone resistance of different vulcanizates can vary markedly according to 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 may be quite different owing to the effects of size and the type and magnitude of deformation. Explanatory notes on the nature of ozone cracking are given in the annex.
Methods for determining resistance to ozone cracking under dynamic strain conditions and combined dynamic and static strain conditions will form the subject of Part 2 of this International Standard. A reference method for estimating the ozone concentration will form the subject of Part 3 of this inter national Standard.