ASTM C740-97

1.1 This practice describes the use of insulations that are characterized by the use of thermal radiation shields positioned perpendicular to the flow of heat. These are commonly referred to as high-performance insulations (HPI), multilayer insulations (MLI), or super insulations (SI) by the industry.

1.2 The practice covers the use of these insulation constructions where the warm boundary temperatures are below 350K.

1.3 Insulations of this construction are typically used when a thermal conductivity of less than 0.00087 W/m[dot]K (0.0005 Btu[dot]ft./h[dot]ft[dot]°F) is required.

1.4 Insulations of this construction are used in a vacuum environment.

1.5 This practice describes the performance considerations, typical applications, manufacturing methods, material specification, and safety considerations in the use of these insulations in cryogenic service.

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

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 limitations prior to use. For specific safety hazards see Section 8.