ISO 18089:2015 describes the procedure for determining the critical crevice temperature (CCT) for stainless steels under potentiostatic control.

The principal advantage of the test is the rapidity with which the CCT can be measured in a single test procedure. The CCT, as determined in this International Standard, can be used as a relative index of performance, for example, to compare the relative performance of different grades of stainless steel.

The test described in this International Standard is not intended to determine the temperature at which crevice corrosion will occur in service.

This method is not intended for materials with critical pitting temperature (CPT) values below 20 °C measured in accordance with ISO 17864, when measured in the same test solution and at the same potential