1.1 This practice is intended as a dimensional standard for preformed thermal insulation for pipes and tubing. 1.2 This practice covers insulation supplied in cylindrical sections and lists recommended single layer inner and outer diameters of insulation having nominal wall thicknesses from 1⁄2 to 5 in. (13 to 127 mm) to fit over standard sizes of pipe and tubing. 1.3 The values stated in inch-pound units are to be regarded as the standard. The values stated in SI units are provided for information only. 1.4 This standard does not purport to address 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.