1.1 This test method describes a procedure for determining the compressive properties of rigid cellular materials, particularly expanded plastics, based on test machine crosshead motion. 1.2 The values stated in SI units are to be regarded as the standard. The values in parentheses are for information only. 1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. Note 1-This test method and ISO 844 are technically equivalent.