How should fireproof building materials be ranked?
5. Civil building 5.1. Fire resistance rating, number of layers and floorage of civil buildings 5.1.1. Fire resistance rating of civil buildings should be classified into four levels of first, second, third and fourth. Unless otherwise specified in the code, the combustion performance and fire endurance of building components with different fire resistance rating should be no less than that of the regulations in Table 5.1.1. Table 5.1.1: Combustion Performance and Fire Endurance (h) of Building Components (Figure) Note: 1. Unless otherwise specified in the Code, the fire resistance rating of the building with wooden pillars as load-bearing and incombustible material as the building wall should be the fourth level; 2. For the suspended ceiling of the building with the second level of fire resistance rating, if it uses non-combustible component, it won't be limited in its fire endurance; 3. For buildings with the second level of fire resistance rating, if it is really difficult for the partition wall of rooms with the area of no less than 100m2 to implement the regulations of the Table, the partition wall can adopt the non-combustible component with fire endurance of no less than 0.3h; 4. For buildings with the first or second level of fire resistance rating, if it is really difficult for the partition wall of both sides of the evacuation walk to implement the regulations of the Table, the partition wall can adopt the non-combustible component with fire endurance of no less than 0.75h. 5. Fire endurance and combustion performance of the residential building component can be implemented in accordance with the provisions of current national standard GB 50368 "Residential Building Code".
According to our national standard GB8624-97, the combustion performance of building materials are divided into the following levels: A class: Incombustible building materials: the material is almost incombustible. B1 class: Flame-retardant building materials: they are better in fire retardation. It is non-combustible when meeting open fire in the air or under high temperature, and it is difficult for the fire to spread quickly. Besides, when the fire source is removed, combustion stops immediately. B2 class: Combustible building material: It has certain fire retardation. In case of open fire in the air or at high temperature, it will immediately burst into flames, and easily lead to the spread of fire, such as the spread to wooden pillars, timber roof truss, timber beams, wood stairs, etc. B3 class: Flammable building material: It has no fire retardant effect at all, but is highly flammable with high fire risk. Hope my answer can be accepted.
Division of fire-proof grade of buildings is one of the most basic measures in the fire-fighting technology and measures of buildings. According to our national code of building design, fire-proof grade of buildings are classified into four levels of first, second, third and fourth, of which the first level is the highest in fire resistance and the fourth level is lowest in fire resistance. Fire resistance rating of buildings depends on the combustion performance and fire endurance of the building component. The so-called building component refers to the walls, foundations, beams, pillars, floors, stairs, ceilings, etc.
