Ordinary EPS insulation materials have an oxygen index of less than 22, which is in the face of open flames, and the more and more prosperous, the combustion performance grade is B3 grade is flammable material. In order to improve the fire performance of EPS, in the ordinary type of EPS resin, adding some flame retardants can greatly improve the oxygen index of EPS. According to the performance of the flame retardant and the amount of addition, the flame retardant EPS is divided into B2 flame retardant EPS and B1 flame retardant EPS. Flame-retardant EPS is a self-extinguishing material, that is, the flame-retardant EPS will also be ignited in the event of an open flame, but will extinguish itself after leaving the fire source. Therefore, the flame retardant EPS is also called self-extinguishing EPS.