Test for Flammability of Plastics — Vertical Burning Method
This standard specifies a method for classifying the burning behavior of vertically oriented specimens (of a certain size) exposed to a flame ignition source under specified test conditions. It is only applicable to quality control test and material selection test, and cannot be used as the criterion to evaluate the ignition risk under actual use conditions.
1 Test Specimen
1.1 Specimen size: length: 130 ± 3 mm long; width:13.0 ± 0.3 mm; thickness: 3.0 ± 0.2 mm.
Note: Tests may also be carried out on specimens of thickness from 2 mm to 13 mm, but such test results can only be compared between the same thickness.
1.2 The surface of test specimens shall be flat and free from any bubbles, flying edges, burrs and other defects.
1.3 The number of test specimens in each group is 5.
1.4 Test specimens may be made by pressure molding and injection molding, or machined from sheets, tubes, bars and insulating parts.
2 Conditioning
2.1 Test specimens shall be conditioned for 48 hours in accordance with GB 2918-82 Plastics — Standard Atmospheres for Conditioning and Testing.
2.2 Test specimens can also be conditioned according to the conditions specified by the manufacturer or to the product standards.
3 Test Materials and Equipment
3.1 A rack with sample clips.
3.2 A Bunsen burner with a pipe length of 100 mm and an inner diameter of 9.5 ± 0.5 mm.
3.3 Medical absorbent cotton.
3.4 Stopwatch.
3.5 Calipers or other measuring tools for measuring flame height.
3.6 In order to exclude toxic fumes from specimen burning, the test shall be carried out in a fume hood. However, the ventilation system shall be turned off during the specimen burning to avoid affecting the test results.
3.7 Supply industrial methane, through appropriate regulators and meters, with a uniform flow rate as a fuel gas.
Note: Natural gas with a heat capacity close to 37 mj/m3 can be substituted for industrial methane. Other fuel gases, such as liquefied petroleum gas (LPG) and gas may also be used through consultation between the parties concerned. In case of dispute, industrial methane must be used.
4 Test Procedures
4.1 The specimen is placed vertically, the upper end is clamped 6 mm by the sample clips, and the lower end is 300 mm away from the medical absorbent cotton layer horizontally laid.
4.2 Light the Bunsen burner about 150 mm away from the specimen and adjust the fuel gas flow to generate a yellow flame 20 ± 2 mm in height in the vertical position of the burner tube. Then open the air inlet valve to ensure that the Bunsen burner produces a blue flame of 20 ± 2mm in height.
4.3 As shown in Figure 1, adjust the center of Bunsen burner tube top surface to be 10 mm away from the lower end of the specimen, aim the flame at the center of the lower end of the specimen, and start timing. If the specimen has molten drips, tilt the Bunsen burner tube to the 13 mm wide side of the specimen by 45°, as shown in Figure 2, and pull back slightly to prevent drips from entering the tube.
1 Test Specimen
2 Conditioning
3 Test Materials and Equipment
4 Test Procedures
5 Evaluation of Results
6 Test Report
Additional Explanation
