1.1 This 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. 1.2 For 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 Practice C 921 to aid material selection. Although vapor retarder properties are not part of this specification, properties required in Specification C 1136 are pertinent to applications or performance. 1.3 The 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). 1.4 This standard does not purport to provide the performance requirements of hourly-rated fire systems. Consult the manufacturer for the appropriate system. 1.5 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. 1.6 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.