How is the distinction between fire grade?
Fireproof material grade: Class A: incombustible building materials, almost no burning material. A1 level: non-combustible, can not afford to fire A2 level: non-combustible, to measure smoke, to qualified. B1 level: flame retardant building materials: flame retardant materials have a better flame retardant effect. It is in the air in case of fire or in the role of high temperature difficult to fire, it is not easy to spread, and when the fire destroyed after the fire immediately stop. B2 grade: flammable building materials: combustible materials have a certain role in flame retardant. In the air in case of fire or under high temperature will immediately fire burning, easy to lead to the spread of fire, such as wooden pillars, wooden truss, wooden beams, wooden stairs and so on. B3 level: flammable building materials, without any flame retardant effect, easy to burn, fire a great danger.
Look at how much concentration the concentration of the higher the better
How is the distinction between fire grade?...
