1.1 This specification covers the composition, dimensions, and physical properties of metal-mesh covered mineral fiber (rock, slag, or glass) blanket and blanket-type pipe insulation (typically on 24 in. (610 mm) diameters or larger) for use on cooled surfaces at temperatures operating below ambient to 0°F (-18°C) and on heated surfaces operating at temperatures up to 1200°F (649°C). Specific applications outside the actual use temperatures shall be agreed upon between the manufacturer and purchaser.

1.2 For satisfactory performance, properly installed protective vapor retarders or barriers shall be used on below ambient temperature applications to reduce movement of moisture through or around the insulation to the colder surface. Failure to use a vapor barrier when insulating below ambient systems creates conditions that, unless otherwise treated will 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 blanket is primarily parallel to the heated surface. This specification does not cover fabricated pipe and tank wrap insulation where the insulation has been cut and fabricated to provide fiber orientation that is perpendicular to the heated surface.

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 See Supplementary Requirements for modifications to paragraphs in this standard when using Specification C 592 in lieu of the United States Department of Defense, Department of Navy, Naval Sea Systems Command, in Washington, DC, Military Specifications No.(s) MIL-I-2818B and MIL-I-2818C.

1.6 The values stated in inch-pound units shall be regarded as the standard. The System International (SI) equivalents of inch-pound units are given in parentheses for information only and are approximate.

1.7 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 requirements prior to use.