The test only concerns rigid plastic materials at a temperature of 20° G to 23° C (b). It is applicable to molded products with a thickness between 3mm and 4.2mm and sheet products with a thickness between 3mm and 13mm. The values obtained can only be used to predict the behavior of plastic materials at elevated temperatures in applications where the factors time, temperature, stress, way of applying the load are identical to those specified in this draft standard. The test method is suitable for determining and controlling the quality of plastic materials. The results obtained are not maximum operating temperatures, due to the variables indicated above.