The type of steel building structures includes the portal rigid steel frame, frame structure, truss structure, and grid structure. The…
The Fire Prevention for Steel Building is very important. Steel is a kind of non-combustible construction material, which has the characteristics of anti-seismic and anti-bending. In practical applications, metal can not only increase the load capacity of buildings but also meet the needs of aesthetic design in architectural design. It also avoids the defects that building materials such as concrete cannot be bent and stretched. Therefore, steel has favored by the construction industry.
Why Need Fire Prevention for Steel Building
Single-story, multi-story, skyscrapers, factory buildings, warehouses, waiting rooms, all made of the steel structure. However, steel as a building material has some unavoidable defects in fire prevention. Its mechanical properties, such as yield point, tensile strength, and elastic modulus, will decrease sharply due to temperature rise.
Steel structure usually loses its bearing capacity at 450 ～ 650 ℃, which causes large deformation to cause the bending of steel columns and beams. As a result, it cannot use due to excessive deformation. Generally, the fire protection of the unprotected steel structures limit is about 15 minutes.
The fire resistance time is also related to the speed of heat absorption of the steel component. Fire prevention treatment must carry out. The purpose is to increase the fire resistance limit of steel structures to the limit range specified in the design code. There are various measures to prevent the steel structure from rapidly rising and deforming during a fire. The key is to adopt different methods according to different situations. Delay the temperature rise of the steel structure and the time for the strength to weaken.
The measures of Fire Prevention for Steel Building
Outer wrapper layer
It is to add an external coating on the surface of the steel structure, which can cast in-situ or sprayed. The cast-in-place solid concrete cladding is usually reinforced with wire mesh or steel bars to limit shrinkage cracks and ensure the strength of the shell. The spraying method can apply a sand pump to the surface of the steel structure at the construction site to form a protective layer. The sand pump can be lime cement or gypsum mortar. At the same time, the outer layer can also be made of prefabricated panels with perlite, asbestos, gypsum, asbestos cement or light concrete, and fixed to the steel structure with adhesives, nails, and bolts.
Water filling (water jacket)
Filling the hollow steel structure with water is the most effective protection against fire. This method can keep the steel structure at a relatively low temperature in a fire. The water circulates inside the steel structure to absorb the heat of the material itself. The heated water can recirculate after cooling, or the cold water can be introduced by pipes to replace the heated water.
The steel structure set in the wall or ceiling made of refractory material or the component enclosed in the gap between the two walls. As long as a little refractory material is added or not added. The purpose of fire prevention can achieve. It is the most economical method of fire prevention.
The technique has the advantages of excellent fire insulation performance. And the geometry of the steel structure does not limit construction, etc. Generally, no additional facilities need to add, and the coating is light in weight and has a particularly decorative effect, which belongs to new advanced fire prevention technology measures.
At present, high-rise steel structure buildings are increasing, especially for some super high-rise buildings, steel structure materials more widely used. Once a fire accident occurs in a high-rise building, the fire cannot extinguish in a short time. It requires us to increase the fire protection of building materials in the design of the building to enhance its fire resistance limit. And this requires us to formulate the necessary emergency response inside the building to reduce casualties and property damage.