who knows how to classify the fire resistant levels of fireproofing material?
Grade of fireproofing material: Class A: Incombustible building material, almost without burning. class A1: Non-combustible, no open flame,class A2: Non-combustible,it needs to measure smoke and be qualified. Class B1: Nonflammable building material: Nonflammable materials have good flame resistance function. when it contacts open fire or is under high temperature, it's difficult to burn and be spreading rapidly, and will stop burn after removing the combustion?source. Class B2: Combustible?building?materials: Combustible materials have good flame resistance function. when it contacts open fire or is put in the air at high temperature, it will immediately burst into flames, and easily result in the spreading of fire, such as wooden column, timber roof truss, timber beam, wooden stairs, etc. Class B3: Inflammability building materials, without any flame resisting effects, easy to burn, and has large danger of fire disaster.
Materials used in construction are called construction materials. The combustion performance of construction materials refers to all physic and chemical changes happened when burning or contacting fire, the properity is measured by combustibility of material surface and flame transmission, heating, smoke,charring, weightlessness, and the producing of toxicity resultant. Our national standard GB8624-97 classifies the combustion performance of construction materials into following several levels. Class A: Incombustible building material, class B1: Nonflammable building material, class B2: Combustible?building?materials, class B3: Inflammability construction materials, generally speaking: first fire resistant level construction is the mixed construction of reinforced concrete structure or brick wall and steel concrete structure; second fire resistant level construction is the steel structure roof truss, reinforced concrete column or mixed structure made by brick wall; third fire resistant level construction is the wood and brick made by wooden roof and brick wall; fourth fire resistant level one is the combustible?structure made by wooden roof, hard-comnustible component wall.
