规定的方法基于测定温度，在温度以恒定速率升高时，标准压头在50 N±1 N的力下，穿透从管道或管件壁上切下的试样表面1 mm。仅适用于热塑性材料，可测量其软化速率迅速变化的温度。基于ISO 306:1994，但适用于板材形式的材料。

The method specified is based on determining the temperature at which a standard indenter, under a force of 50 N ± 1 N, penetrates 1 mm into the surface of a test piece cut from the wall of a pipe or fitting while the temperature is raised at a constant rate. Is applicable only to thermoplastics materials for which it is possible to measure the temperature at which the rate of softening becomes rapid. Is based on ISO 306:1994 which, however, applies to materials in the form of sheets.