ISO 24999:2008规定了测定柔性多孔材料在重复压缩至固定应变水平时厚度损失的方法。它特别适用于柔性聚合物多孔材料制造中的质量控制。 另一个程序已经存在，即ISO 3385:该程序通过试样的恒定应力载荷而不是恒定应变来测量柔性聚合物多孔材料的疲劳特性。它构成了ISO 5999中材料分类系统的基础。 这两种疲劳程序相辅相成，可用于预测最终使用性能。 本国际标准中使用的程序和设备允许在任何时间测试大量试样，而ISO 3385仅允许在压缩装置下一次测试一个试样。

ISO 24999:2008 specifies a method for determining the loss in thickness of flexible cellular materials when compressed repetitively to a fixed level of strain. It is particularly useful for quality control in the manufacture of flexible polymeric cellular materials. Another procedure already exists as ISO 3385: this measures the fatigue characteristics of flexible polymeric cellular materials by constant-stress loading of the specimen rather than constant strain. It forms the basis of a material classification system in ISO 5999. These two fatigue procedures are complementary to each other and can both be useful in the prediction of end-use performance. The procedure and equipment used in this International Standard allow testing of a large number of test pieces at any one time, whereas ISO 3385 only allows testing of one test piece at a time under the compression device.