BS EN 60811-401:2012 pdf download – Electric and optical fibre cables — Test methods for non-metallic materials Part 401 : Miscellaneous tests — Thermal ageing methods — Ageing in an air oven The ageing test a) or b) and the loss of mass test d) may be combined and carried out on the same test pieces when the aging time and aging temperature are the same. Iln general，,mechanical characteristics are measured after treatment, but in some cases, theconductor and the separator, if any, cannot be removed without damaging the insulation and abending test is realized on the circular conductor up to and including 16 mm2.Ageing followedby the bending test is considered the acceptance procedure in case of dispute. 4.2Influence of the ageing treatment on the mechanical characteristics4.2.1 Apparatus The ageing treatment is realized in an oven with natural air flow or air flow by pressure.Theair shall enter the oven in such a way that it flows over the surface of the test pieces andleaves near the top of the oven.The oven shall have not less than 8 and not more than 20complete air changes per hour at the specified ageing temperature.Two test methods formeasuring air flow through an oven are given in Annex A. Unless otherwise specified in the relevant cable specification, a rotating fan inside the oven isallowed when testing rubber compounds.For all other compounds a fan shall not be usedinside the oven, and in cases of dispute,rubber compounds shall also be tested in an ovenwhich is designed to operate without a fan rotating inside it. 4.2.2Sample and test pieces preparation The sample of the cable，or sheath removed from the cable，or samples of core,cut intopieces which are sufficiently long, shall be taken, preferably from positions close to that fromwhich the samples for the tensile tests without ageing are taken in accordance withIEC 60811-501. Test pieces, dumb-bell or tubular, are prepared according to lEC 60811-501. Test pieces can consist of samples of core, cut into pieces which are sufficiently long. lf, afterageing，the conductor and the separator，if any,can be removed without damaging theinsulation, preparation of test pieces shall be carried out according to Annex B(Clause B.2).For circular conductors up to and including 16 mm3and having plain or metal coated wiresand also when a separator around the conductor is included, a bending test is carried out onthe aged test pieces. 4.2.3Ageing procedure4.2.3.1General This test shall be carried out not less than 16...
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