What is the flame retardant standard of XPS extruded board?

　　At present, the new GB8624 "classification of combustion performance of building materials (products)" standard is under revision and joint review, and will be issued for a long time. The standard adopts the new EU standard. The current national standard GB8624 classification of combustion performance of building materials (products) stipulates that grade B2 is the lower flame retardant requirement of XPS extruded board (oxygen index ≥ 26).

　　Class B2 is the test result of XPS extruded board in the laboratory according to the national standard. It has strict test conditions and can not be simply understood as self extinguishing. However, in the construction site, many people ignite the facade (non edges and corners) of the upright (non inclined) XPS extruded board with an open fire to see whether they leave the fire source and extinguish themselves. The method is to test the flame retardant performance of XPS extruded board in the construction site. It can be used for reference, but it is not scientific and rigorous.