IEC 60754-1:2011 pdf – Test on gases evolved during combustion of materials from cables -Part 1: Determination of the halogen acid gas content.
The flow rate of air shall be adjusted by means of a needle valve to the value specified in 5.6 and shall be kept constant during the test.
The test specimen shall be heated using the heating regime determined in 7.3.1,
WARNING The opratol should lake precautions. e.g. It, wearing of •y• protection and suitable potctive clothing, because certain materials Ignite quickly, and can cause ‘blow back’ ot hot gases. Care should also be tak.n to avoid overpressurization of th. system. and to allow for venting of exhaust gases Guidanc, on h. avoidance of ‘bfow back’ is given In NOTE 2of 5.1.
7A Washing procedure
Following the heating procedure. all the bottles used shall be disconnected, and the contents washed into a 1 000 ml volumetric flask. Using distilled or demineralized water, the bottles, the connecting links and, after cooling, the end of the quartz glass tube including the silica wool (if used) shall also be washed Into the flask, and the contents made up to 1 000 ml.
7.5 Determination of halogen acid content
7.5.1 Blank test
Prior to conducting a test on a test specimen, a blank test shall be carried out using the test procedure given in 7.3.2 but without a test specimen in the combustion boat.
After cooling lo ambient temperature, 200 ml of the solution shall be measured into a conical flask using a suitable pipette, and the following reagents introduced successively:
a) approximately 4 ml of concentrated nitric acid:
b) 20 ml of 0,1 M silver nitrate, measured with a pipette:
C) approximately 3 ml of either nitrobenzene, toluene or iso-amyl alcohol.
The contents shall be well shaken to achieve conglomeration and coating of the silver halide that is formed by the reaction.
1 ml of a 40 % (weightvolume) aqueous solution of ferric ammonium sulphate containing a few drops of 6 M nitric acid shall then be added and the whole mixed together. The solution shall then be titrated with 0.1 U ammonium thiocyanate solution using a burette and the whole shaken or stirred vigorously. The end’point shall be the red end-point for the titration.
The volume, B, of 0,1 U ammonium thiocyanate solution shall be recorded.
NOTE his recommended that the blank test be carried oat prior to each testing campaign and whenever a new batch of sodium hydroxide solution, ilve, nitrate solution. ammomuum thiocyanale solution or distilled or d.mineralizd waler is started.
7.5,2 Material test
The test procedure given In 7.3.2 shall be carried Out with a test specimen in the combustion boat.
After cooling to ambient temperature, 200 ml of the solution shall be measured into a conical flask using a suitable pipette and the following reagents introduced successively:
a) approximately 4 nil of concentrated nitric acid:
b) 20 ml of 0,1 U silver nitrate, measured with a pipette:
c) approximately 3 ml of either nltrobenzene, toluene or Iso-amyl alcohol.
The contents shall be well shaken to achieve conglomeration and coating of the silver halide that is formed by the reaction.
8Evaluation of the test results
The halogen acid gas content of the material，Cm， shall be taken as the mean of thedetermination of the two test specimens.
The individual values shall not vary from the mean by more than ±10 % where the halogenacid gas content is 2 5 mg/g.
Record C= 5 when the amount of halogen acid is less than 5 mg/g-9Performance requirement
No requirements for conformity are included in this standard.
10 Test report
The test report shall include the following information:a) a full description of the material tested;
b) the number of this standard;
c the halogen acid gas content of the material (Cm);
d) the analytical method used for the determination of the halogen acid gas content (if not as
given in this standard);
e) the supplier’s reference used for reagents 3) and 6)(as per 5.9) shall be reported.