4.1 In many applications, the vapor retarders used on a thermal insulation will be exposed to the temperatures listed in 7.2. Cracking or delamination of the retarder under these conditions would, in most cases, cause it to lose its effectiveness as a vapor retarder material.

1.1 This test method covers the visual determination of the thermal integrity of flexible water vapor retarders for those materials classified under Specification C1136, including plastic, foil, or paper and composites of two or more of these materials to temperatures listed in the specification or purchase contract. The vapor retarders are intended for use at temperatures of − 20 to 150°F (−29 to 66°C). This test method does not cover mastics or barrier coatings applied in liquid form or materials intended for use as weather barriers.

1.2 The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematical conversions to SI units that are provided for information only and are not considered standard.

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.