The relaxation property depends on the temperature and the initial stress. Thus, in order to compare tests, it is recommended to always use the same proportion of the tensile strength for introducing the test strain. Higher initial stresses will reduce the relaxation times. The initial stress should not be greater than 75 % of the tensile strength βt. Recommended test temperatures are + 20 °C, + 5 °C, − 10 °C and − 25 °C.