What is the appropiate thickness if fire resistant time for ultra thin steel structure coating is 2.5 hours?
Hello steel structure can adopt surrounding concrete or brick, fireproof coating, fireproof board coating and composite structure for its fire resisitance. Fire resisitance board can be divided into thick fire protection plate and thin plate, the thickness of the plate thickness of the fire is between 20 ~ 50mm, mainly includes calcium silicate fireproof board and expansion boring stone fire board, the main varieties are KB board, CF; thin fireproof plate is between 6 ~ 15mm thick, the main varieties include enforced short fiber cement plate, ordinary enforced fiber silicate calcium board and glass cloth reinforced inorganic board.
A level fire resistant steel structure building steel column cannot be constructed with super thin steel structure fire retardant coating, because the ultra thin steel structure fire retardant limit is less than 3 hours. Thin fire retardant coating for steel structure is water borne fireproof coatings painted on the surface of steel structure. It will form carbonized fireproof heat insulation protective layer to insulate oxygen and delay the speed of heating steel structure when it catches on fire, avioding the rapid temperature rise of steel structure and increasing its fire resistant limit. Fire resistance performance: The 2mm coating ≥ 60min, 3mm 100min.
According to the "code for fire protection design of tall buildings", the fire resistance time of the component is at the first level: 3 hours, beam: 2 hours, floor: 1.5 hours;if fire resistance level is level the requirement for time of fire resistance component is the column: 2.5 hours, beam: 1.5 hours, floor: 1 hours. For fire resistant coating, fire resistance time for ultra-thin fire retardant coating is shorter than 1.5 hours. If the time exceeds 1.5 hours, thick fire resistive coating should be used. Steel structure can adopt surrounding concrete or brick, fireproof coating, fireproof board coating and composite structure for its fire resisitance. Fire resisitance board can be divided into thick fire protection plate and thin plate, the thickness of the plate thickness of the fire is between 20 ~ 50mm, mainly includes calcium silicate fireproof board and expansion boring stone fire board, the main varieties are KB board, CF; thin fireproof plate is between 6 ~ 15mm thick, the main varieties include enforced short fiber cement plate, ordinary enforced fiber silicate calcium board and glass cloth reinforced inorganic board. As is known to all, steel structure usually will lose bearing capacity usually in 450 to 650 degree, leading to deformation, steel column and beam bending, and be no longer usable at last. Generally fire resistant limit of unprotected steel stucture is about 15 minutes. 1.5 hours;if fire resistance level is level the requirement for time of fire resistance component is the column: 2.5 hours, beam: 1.5 hours, floor: 1 hours. Steel structure an use surrounding concrete (or masonry), fire retardant coating, fire retardant plate and compround structure to achieve the required refractory limit. Hope my answer will help you.
