These test methods are designed to compare related materials under controlled conditions and their ability to maintain a given compressive stress as a function of time. A portion of the torque loss on the bolted flange is a result of creep relaxation. Torque loss can also be caused by elongation of the bolts, distortion of the flanges, and vibration; therefore, the results obtained should be correlated with field results. These test methods may be used as a routine test when agreed upon between the consumer and the producer.

Note 1—Test Method B was developed using asbestos gasket materials and at issuance substantiating data were not available for other gasket materials.

FIG. 1 Relaxometer, Test Method A

1.1 These test methods provide a means of measuring the amount of creep relaxation of a gasket material at a predetermined time after a compressive stress has been applied.

1.1.1 Test Method A Creep relaxation measured by means of a calibrated strain gauge on a bolt.

1.1.2 Test Method B Creep relaxation measured by means of a calibrated bolt with dial indicator.

1.2 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.

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.