This specification covers asbestos textile materials used for electrical insulating purposes having a specified minimum mass % of asbestos fiber, excluding the mass of other inorganic reinforcing material that may be present. Asbestos textiles are classified into three types (Types II, IV, and VI) according to magnetic rating, and into grades (Underwriters, A, AA, AAA, and AAAA) according to the percentage of asbestos content by mass. Textile materials shall meet chemical composition (asbestos content) and magnetic rating specific to their grade and type.

1.1 This specification covers asbestos textile materials used for electrical insulating purposes having a minimum of 80% asbestos fiber, by mass, excluding the mass of other inorganic reinforcing material that may be present.

Note 1—Specifications for other asbestos textile products are covered in Specifications D299, D315, D375, D1061, and D1571.

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 Warning—Breathing of asbestos dust is hazardous. Asbestos and asbestos products present demonstrated health risks for users and for those with whom they come into contact. In addition to other precautions, when working with asbestos-cement products, minimize the dust that results. For information on the safe use of chrysoltile asbestos, refer to “Safe Use of Chrysotile Asbestos: A Manual on Preventive and Control Measures.”

1.4 The following safety hazards caveat pertains only to the test methods, Section 10, described in this specification: 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 hazard, see 1.3.