Steel is a kind of building material that will not burn, it has the characteristics of earthquake resistance, bending resistance and so on. In practical applications, steel can not only relatively increase the load capacity of buildings, but also meet the needs of architectural design and aesthetic modeling, and also avoid the defects that concrete and other building materials cannot be bent and stretched. Therefore, steel has been favored by the construction industry., Single-storey, multi-storey, skyscrapers, factories, warehouses, waiting rooms, waiting rooms, waiting halls, etc. are commonly used in steel. However, as a building material, steel has some unavoidable defects in fire prevention. Its mechanical properties, such as yield point, tensile strength and elastic modulus, will drop sharply due to the increase of temperature.

Steel structures usually lose their bearing capacity at temperatures of 450 degrees Celsius to 650 degrees Celsius, resulting in large deformation, resulting in steel columns and steel beams bending, resulting in excessive deformation and can not continue to use, generally unprotected steel structures The fire resistance limit is about 15 minutes. The length of this time is also related to the speed at which the component absorbs heat. In order to overcome the deficiency of fire prevention in the practical application of steel structure materials, fire prevention treatment must be carried out, the purpose of which is to increase the fire resistance limit of steel structure to the limit range specified in the design specification. To prevent the steel structure from rapidly heating up and collapsing in a fire, the measures are varied. The key is to adopt different methods according to different situations, such as using insulation and refractory materials to block the flame from directly burning the steel structure, reducing the speed of heat transfer and delaying the temperature rise and strength weakening of the steel structure. But no matter what method is taken, the principle is the same. Therefore, the author believes that in reality, four kinds of steel structure fire protection measures must be given attention.

1. outer cladding. As the name implies, is in the appearance of the steel structure to add the outer layer, the use of spraying construction. Special spraying equipment is used to spray "Jinma steel structure fireproof slurry (single component)" on the surface of steel structure to form a protective layer. The thickness of fireproof slurry can be designed according to the fire prevention requirements, which can meet the fire resistance limit for more than 2~3 hours. It is a fireproof slurry with good performance and high cost performance on the market at present.

2. water-filled water jacket. Hollow steel structure filled with water is the most effective protective measures against fire. This method enables the steel structure to maintain a low temperature in the fire, and the water circulates in the steel structure to absorb the heat of the material itself. The heated water may be recycled after cooling or cold water may be introduced through a pipe to replace the heated water.

3. shielding. The steel structure is set in the wall or ceiling composed of refractory materials, or the components are hidden in the gap between the two walls. As long as a little refractory material is added or not, the purpose of fire prevention can be achieved. This is one of the most economical methods of fire prevention.

4. intumescent material. The use of steel structure fire retardant coating protection components, this method has the advantages of good fire insulation performance, construction is not limited by the geometric shape of the steel structure, generally do not need to add auxiliary facilities, and the coating quality is light, there is a certain beautiful decorative role, belongs to the modern advanced fire prevention technology measures.

At present, the number of high-rise steel structure buildings is increasing, especially some super high-rise buildings, the use of steel structure is more extensive. In the event of a fire accident in a high-rise building, the fire cannot be extinguished in a short period of time, which requires us to increase the fire protection of building materials in the building design to enhance its fire resistance limit, and to develop the necessary emergency response within the building. Plan to reduce casualties and property losses.