GB/T 2406.3-2022 Active

This document describes the test method for determining the minimum oxygen concentration required to maintain the combustion of small upright specimens in an oxygen-nitrogen gas mixture at temperatures ranging from 25 °C to 150 °C (typically 40 °C to 150 °C) under specified test conditions. The results are defined as the temperature index at the test temperature, which is the typical temperature that plastic materials may be exposed to under actual overheating conditions.
This document is applicable to strip or sheet materials with a thickness of less than 10.5 mm that can stand upright on their own at the test temperature, but it is not applicable to Type V specimens requiring a support frame as specified in Table 2 of ISO 4589-2:2017.
This document is applicable to solid materials, laminates, or foams with an apparent density greater than 100 kg/m3, as well as certain foams with an apparent density less than 100 kg/m3. It also provides a method for vertically supporting flexible sheets or films.
This document also describes the method for determining the flammability temperature (FT) of small upright specimens under specified test conditions when the oxygen volume fraction is 20.9% (see Appendix A). This method is only applicable to tests below 400 °C and is not suitable for materials with an oxygen index lower than 20.9%.
Note: This document may not be applicable to materials that exhibit strong shrinkage after heating, such as highly oriented films.
Note: Refer to ISO 3582 for the description of evaluating the flame propagation characteristics of foams with an apparent density less than 100 kg/m3.