The hot compression properties of a gasket material, including creep resistance and compression set, are a major factor with regard to the selection of a given material for use in a particular sealing application. The significance of the test method is based, in part; on the assumption that if a material exhibits too much creep at elevated temperature that it will no longer function as effectively as a seal. This assumption can only be used as a guide; however, since exact yield or failure points are difficult to define for gasket materials (which are usually viscoelastic in nature). Two or more materials can be compared to determine differences in their hot compression properties. A sample of material can be compared to an established standard or previously determined characteristics on original lots of the same material, for quality assurance purposes.

Samples are to be tested with a raised profile insert or calibration ring described in 6.3 and Fig. 1 so that the area (2042 mm² (3.17 in.²)) remains constant during the test.

FIG. 1 Test Assembly for Determining Hot Compression