本文件规定了测定硫化橡胶和热塑性橡胶在低温下压缩永久变形特性的两种方法。 方法1源自ISO 815-1中使用的方法。方法2使用指定的测试设备，允许在恢复过程中测量和记录试样厚度。由于方法2中回收期间施加的载荷，两种方法给出的结果之间无法建立相关性。 注:当橡胶处于压缩状态时，可能会发生物理或化学变化，阻止橡胶在变形力释放后恢复到其原始尺寸。结果是一组，其大小取决于压缩的时间和温度，以及恢复的时间、温度和条件。 在低温下，玻璃硬化或结晶效应引起的变化占主导地位，由于这些效应通过提高温度而逆转，因此，测量始终在试验温度下进行。

This document specifies two methods for the determination of the compression set characteristics of vulcanized and thermoplastic rubbers at low temperatures. Method 1 derives from the methodology used in ISO 815-1. Method 2 uses a specified testing device, allowing to measure and record the test piece thickness during recovery. Due to the load applied during recovery in method 2, no correlation can be established between the results given by both methods. NOTE When rubber is held under compression, physical or chemical changes that prevent the rubber returning to its original dimensions after release of the deforming force can occur. The result is a set, where the magnitude of which depends on the time and temperature of compression as well as on the time, temperature, and conditions of recovery. At low temperatures, changes resulting from the effects of glass hardening or crystallization become predominant and, since these effects are reversed by raising the temperature, therefore, the measurements are always taken at the test temperature.