GB/T 8333-2008 stipulates the use of vertical combustion method to test the combustion performance of rigid foam plastics. The standard clarifies the test principle, sets requirements for the specifications and performance of Combustion test chambers, gas lamps and other equipment, specifies the preparation of the sample, including size, quantity and state adjustment, and standardizes the vertical combustion test process, such as ignition position, ignition time and combustion phenomenon observation records. Through this standard, the combustion characteristics of rigid foam plastics in the vertical direction can be uniformly evaluated, providing a basis for manufacturers to control product mass and select safe materials, and helping to improve the safety of related products in fire scenarios.