Four Methods of Fire Protection for High rise Steel Structure Buildings
The steel structure will lose its bearing capacity at the temperature of 450~650 ℃ on weekdays, causing great deformation and bending of steel columns and beams. As a result, it can not be used continuously due to excessive deformation. Generally, the fire endurance of unprotected steel structures is less than 15 minutes. The length of this time is also related to the heat absorption rate of the component.
In order to overcome the shortcomings of fire protection in practical application of steel structure materials, fire protection treatment must be carried out, with the purpose of raising the fire resistance limit of steel structure to the limit range specified in the design code. Prevent steel structure from deformation and collapse due to rapid temperature rise in fire alarm. The methods are various, and the key is to adopt different methods according to different situations. For example, thermal insulation and refractory materials are used to block the flame and directly burn the steel structure, reducing the speed of heat transfer and delaying the time of temperature rise and strength weakening of the steel structure. However, no matter what method is adopted, the rationale is consistent.
The following describes several fire protection four methods for steel structures.
1、 Outsourcing layer
It is to add an outer layer on the surface of the steel structure, which can be cast in situ or sprayed. The outer layer of cast-in-situ solid concrete is usually strengthened with steel wire mesh or reinforcement to limit the compression cracks and ensure the strength of the shell. Spraying method can be used to apply sand pump outside the steel structure on the construction site to form a protective layer. The sand pump can be made of lime cement or gypsum mortar, or mixed with perlite or asbestos. At the same time, the outer layer can also be made of perlite, asbestos, gypsum or asbestos cement, and light concrete, and fixed on the steel structure with adhesives, nails, and bolts.
2、 Water filling (water jacket)
The hollow steel structure filled with water is an effective way to prevent fire. This method can keep the steel structure building at a lower temperature in the fire alarm, and the water circulates in the steel structure to absorb the heat of the material itself. The heated water can be recycled after cooling, or cold water can be introduced from the pipe to replace the heated water.
3、 Fence
The steel structure is set in the wall or ceiling composed of refractory materials, or the components are wrapped in the leisure time between two walls. As long as a little or no refractory materials are added, the purpose of fire prevention can be achieved. This is an economical fire prevention method.
4、 Expansive material
The steel structure fireproof coating is used to protect the components, which has the advantages of good fireproof and thermal insulation performance, and the construction is not limited by the geometric shape of the steel structure. Generally, it is not necessary to add measures to help, and the coating is light in weight, with a certain aesthetic effect, which belongs to modern fire prevention techniques.
The number of high-rise buildings is increasing, especially some high-rise steel structure buildings, which use more steel structure materials. Once a fire occurs in a high-rise building, the fire cannot be extinguished in a short time. This requires us to increase the fire protection of building materials in architectural design to enhance its fire resistance limit, and formulate emergency plans inside the building to reduce casualties and losses.
