ASTM C 612 : 2025

1.1This specification covers the classification, composition, dimension, and physical properties of mineral fiber (rock, slag, or glass) semi-rigid and rigid board intended for the use as thermal insulation on surfaces operating at temperatures between 0°F (-18°C) and 1800°F (982°C). For specific applications, the actual temperature limits shall be agreed upon between the supplier and the purchaser.

1.2For satisfactory performance, properly installed protective vapor retarder or barriers shall be used on below ambient temperature applications to reduce movement of water through or around the insulation towards the colder surface. Failure to use a vapor retarder or barrier can lead to insulation and system damage. Refer to Guide C755 for consideration in the selection of water vapor retarders and Guide C1423 for specific guidance in selecting jacketing materials. Although vapor retarder properties are not part of this specification, properties required in Specification C1136 are pertinent to applications or performance.

1.3The orientation of the fibers within the boards is primarily parallel to the principal surface (face). This specification does not cover fabricated pipe and tank wrap insulation where the insulation has been cut and fabricated to provide a fiber orientation that is perpendicular to the surface (face).

1.4This standard does not purport to provide the performance requirements of hourly-rated fire systems. Consult the manufacturer for the appropriate system.

1.5The 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.

1.6This 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, health, and environmental practices and determine the applicability of regulatory limitations prior to use.

1.7This 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.