IEC 60754-1 pdf download.Test on gases evolved during combustion of materials from cables – Part 1: Determination of the halogen acid gas content
1 Scope
This part of IEC 60754 specifies the apparatus and procedure for the determination of the amount of halogen acid gas, other than hydrofluoric acid, evolved during the combustion of compounds based on halogenated polymers and compounds containing halogenated additives taken from electric or optical fibre cable constructions. NOTE 1 This test method is not able to determine hydrofluoric acid. A suitable method may be found in IEC 60684-2. NOTE 2 This test method may be used to test materials to be used in cable manufacture, but a declaration of cable performance should not be made based on such a test. NOTE 3 The relevant cable standard should indicate which components of the cable should be tested. NOTE 4 For the purposes of this standard, the term “electric cable” covers all insulated metallic conductor cables used for the conveyance of energy or signals. The method specified in this standard is intended for the testing of individual components used in a cable construction. The use of this method will enable the verification of requirements which are stated in the appropriate cable specification for individual components of a cable construction. NOTE 5 By agreement between the producer and purchaser, the methodology given in this standard may be used to test combinations of materials representing a cable construction, but a declaration of cable performance to this standard should not be made based on such a test. Information on such a method is given in Annex A. For reasons of precision this method is not recommended for reporting values of halogen acid evolved less than 5 mg/g of the sample taken.
4 Test method principle
The material under test shall be heated in a stream of dry air and the gases shall be absorbed in 0,1 M sodium hydroxide solution contained in wash bottles. The amount of halogen acid shall then be determined by acidifying the solution with nitric acid, adding a measured volume of 0,1 M silver nitrate solution and back titrating the excess with 0,1 M ammonium thiocyanate, using ferric ammonium sulphate as the indicator. NOTE 1 Other analytical methods having at least the same precision may be used, but in case of dispute the method given in this standard is the one to use. NOTE 2 Although both hydrogen chloride and hydrogen bromide are detected by this analytical method, the halogen acid content is reported as if all the halogen acid is hydrogen chloride.
5 5.1 Test apparatus
The apparatus is shown in Figures 1 to 5. The assembly of the components which constitute the test apparatus shall be leak-tight. The connecting distances between the quartz glass tube and the first bottle and between subsequent bottles shall be as short as possible. Glass or silicone rubber tubing shall be used for these connections. NOTE 1 At the exit side of the quartz glass tube, as close to the end as possible, it is permitted to place a plug of silica wool to aid collection of condensates. NOTE 2 A third empty bottle, of the same size as the gas washing bottles, placed before the gas washing bottles, may be used to improve safety, i.e. to prevent suck back of water into the quartz glass tube. 5.2 Tube furnace The length of the heating zone of the furnace shall be within the range 480 mm to 620 mm, and its inside diameter shall be within the range 38 mm to 62 mm. It shall be equipped with an adjustable electrical heating system. 5.3 Quartz glass tube For the test, a quartz glass tube shall be introduced into the tube furnace. The tube shall be approximately concentric to the furnace. It shall be resistant to the action of corrosive gases. The inside diameter of the tube shall be within the range 30 mm to 46 mm. The tube shall protrude on the entrance side of the furnace by a length of between 60 mm to 200 mm, and on the exit side by between 60 mm to 1 00 mm. The initial clearance shall allow for thermal expansion. For the purposes of measurement of the protrusion distances, the tube shall be regarded as that part of essentially constant diameter. NOTE furnace. The outer diameter of the tube should be chosen with due regard to the inside diameter of the tube Prior to each test, the tube shall be cleaned throughout its length by being calcined at approximately 950 °C.
IEC 60754-1 pdf download
