Document aJ7rOnYdr1gGRoXZJ8jv8LJve

SEPTEMBER 4, 1911 ASBESTOS WIRES - ULUS 17 11.5 The impregnating compound shall rrlum its iniiial qualities during the Ufc of the wire and shall not develop any damaging chemical action within itself or with any other component of the finished wire. 11.6 Thef insulation on a specimen of finished conductor ft to be inspected visually to determine whether or not it complies with the requirements in paragraphs 11.1--11.5 with respect to general construction. The thickness of the insulation is to be determined in accordance with paragraph 15.4. 11.7 The insulation, after removal of uny exterior material other than asbestos, shall comply with the requirements in paragraphs 23.1,23.1A-- 23.IF, 2S.2, 25.1-25.4, and 27.2-27.5. Pirmtiph 11,7 rtvtnd 3plmb*r4, 19S1 Asbestos Content 11.8 STRAIGHT ASBESTOS - If reinforcing glass-fiber threads arc not employed, Class A asbestos, after the impregnating compounds have been removed from the insulation, shall contain not less than 80 percent by weight of asbestos. 11.9 To obtain representative material for ihc test, the asbestos is to be removed from a 3--4-ft or 900--1200-mm length of conductor and cut into shon sections about 1/8 inch or 3 mm in length. Reinforcing cotton threads and cotton binder threads are not to be removed even if such threads serve as an identifying marker. These pieces are to be well mixed and the impreg nating compounds are then to be removed with an organic solvent. ' *11.10 A specimen of the asbestos (with the impregnating compounds removed) weighing ap proximately 5 gm is to be dried to a constant weight Wj in a weighed crucible nt a temperature of 1105C (2S09F), ignited in an electric fumacc at a temperature of 80020C (1472 S6F) for 60 minutes, cooled to room tempera ture in a desiccator, and then weighed again W,,, The percentage of asbestos in the specimen is then to be calculated bv means of the formula in which X is the percentage of asbestos, Wj is the weight of the. dried specimen before ignition, W2 is the weight after ignition and drying, and O.Hfi is a multiplying facLor reflecting the fact that chrysolite asbestos usually contains about 14 percent water of crystallization. 11.11` If the asbestos insulation is known to have more or less than 14 percent of water crystal lization, the factor 0.86 in the formula in para graph 11.10 is to be adjusted accordingly, 11.12 ASBESTOS AND GLASS - If reinforcing glass-fiber threads are employed, Class A asbestos tape, after the impregnating compounds have been removed from the insulation, shall not contain less than SO percent by weight of asbestos. 11.13 Insulation consisting of asbestos and glass shall not show a loss in weight of more than 30 percent after ignition at a temperature that eliminates all combustible material and water of crystallization in the asbestos. 11.14 Specimens of the insulation arc to be prepared uml ignited as indicated in paragraphs 11.9 and 11.10. After ignition, the weight W2 is not to he less than 70 percent of Wj. 11.15 Insulation consisting of asbestos and glass shall not contain more titan 9 percent by weight of carbon (corresponding to a maximum content of 20 percent by weight of combustible material). 11.16 The carbon content is to he determined from insulation from which the impregnating compounds have been removed us indicated in paragraph 11.9. A sample weighing approxi mately 1 gm is to he dried to constant weight at 1105C (2309F) and then ignited In a stream of oxygen at 90020C (165236F). Tire evolved carbon dioxide is to be absorbed in an acceptable medium, and the carbon content is (o be calculated from the increase in weight of the medium. *ltcplaccs page 17 dated June l, 19S1 # COPYRIGHT 1076,-1901 UNDERWRITERS LABORATORIES INC. 0049 SC-ELEC-07850