1.1 This specification covers glass felts impregnated to varying degrees with asphalt intended to be used with asphalts conforming to the requirements of Specifications D312/ D312M or D7654/D7654M in the construction of built-up roofs, and with asphalts conforming to the requirements of Specification D449/D449M in the construction of waterproofing systems. 1.2 The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in each system may not be exact equivalents; therefore, each system shall be used independently of the other. Combining values from the two systems may result in non-conformance with the standard. 1.3 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.