In most of the applications it is important to use cables which retard flame in case of fire, and are self extinguishing when the source of fire is removed. This determination is carried out by subjecting a portion of finished cable to a flammability test. This test is conducted with the help of a flammability tester under In this test, the test specimen is suspended vertically inside a drought proof enclosure and ignited with the help of either one or two burners. The time for extinguishing of flame after shutting off the burners and the length of scorched portion are determined and compared against specified values to evaluate the flammability of the cable.
The Flammability Tester for cables consists of a three-sided metal enclosure having an open front and closed top and bottom. The base is covered with a sheet of asbestos. The test specimen is help vertically in the centre of the enclosure in two clamps, each approximately 25 mm wide. The clamps are positioned such that the distance between the top of the bottom clamp and bottom of the top clamp is as specified.
Three gas burners inclined at angles of 45° are provided, one for testing cables up to 50 mm diameter and the other two for testing cables of above 50 mm diameter. Each burner has an individual control valve with which the flame can be regulated. A ball valve is provided to stop the flow of gas to the apparatus completely.
The equipment is finished in shore Blue metallic painting and bright chrome plating for giving it a corrosion resistant finish.
IS 10810 (Part 53) – 1984 : Methods of Tests for Cables
Part 53 : Flammability Test.