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, 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.