1.1 These test methods cover the testing of rigid tubes used in electrical insulation. These tubes include many types made from fibrous sheets of basic materials, such as cellulose, asbestos, glass, or nylon, in the form of paper, woven fabrics, or mats, bonded together by natural or synthetic resins or by adhesives. Such tubes include vulcanized fiber and thermosetting laminates, as well as tubes made from cast, molded, or extruded natural or synthetic resins, with or without fillers or reinforcing materials.

1.2 Tubes tested by these test methods are most commonly circular in cross-section; however, non-circular shapes are also in commercial use. To the extent that the individual methods are compatible with a particular non-circular shape, these test methods are applicable to these other shapes. For tests on non-circular tubes, appropriate comments should be included in the test report, including details of orientation of test specimens with respect to the cross-section of the tube.

1.3 The procedures appear in the following sections:

ASTM Method Procedure Sections Reference Compressive Strength (Axial and Diametral) 11 to 16 E4 Conditioning 3 ... Density 19 to 23 ... Dielectric Strength 24 to 31 D 149 Dimensional Measurements 4 D 668 Dissipation Factor and Permitivity 32 to 34 D 150 Tensile Strength 5 to 10 E 4 Water Absorption 17 to 18 D 570

1.4 The values stated in inch-pound units are to be regarded as the standard.

1.5 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 a specific hazard statement, see 25.1.1.