3.1 This test method is designed to compare related laminated composite gasket materials under controlled conditions and their short-time compressibility and recovery at room temperature. It measures compressibility with a matched pair of opposing upper and lower penetrators which provide better precision and bias than methods using an upper penetrator and a lower anvil. It is difficult to prepare undistorted test specimens from laminated composite gasket materials which will lay flat on an anvil. Also, with many composites having rigid inner layers the load on the upper penetrator is distributed over the bottom anvil area resulting in a lower than actual compressibility reading. This test method may be used as a routine test method when agreed upon between the purchaser and the producer.

1.1 This test method covers determination of the short-time compressibility and recovery at room temperature of laminated composite gasket materials.

1.2 This test method is not intended as a test for compressibility under prolonged stress application, that is “creep,” or for recovery following such prolonged stress application, the inverse of which is generally referred to as “compression set.” Also, it is only intended for tests at room temperature.

1.3 The values stated in SI units are to be regarded as the standard. The inch-pound units given in parentheses are for information only.

1.4 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.

1.5 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.