The steel structure and stainless steel grid structure usually lose the bearing capacity in 450-650 ℃ temperature, which leads to the bending of steel column and steel beam. As a result, the steel structure can not be used because of excessive deformation. Generally, the fire resistance limit of unprotected steel structure is about 15 minutes. The length of this time is also related to the rate of heat absorption. In order to overcome the shortcomings of fire prevention in the practical application of steel structure materials, it is necessary to carry out fire prevention treatment, the purpose of which is to increase the fire resistance limit of steel structure to the limit range specified in the design code. There are various measures to prevent the steel structure from deformation and collapse due to rapid temperature rise in fire. The key is to adopt different methods according to different conditions, such as using heat insulation and refractory materials to block the flame to directly burn the steel structure, reducing the speed of heat transfer and delaying the time of temperature rise and strength weakening of steel structure. But no matter what method is adopted, the principle is the same.
Whether the stainless steel grid of steel structure of grid structure is painted with fire retardant coating shall be determined according to the fire risk category. The code for fire protection design of buildings clearly stipulates that class D and E may not be applied, while class C and above must be painted. As building materials, steel has some unavoidable defects in fire prevention. Its mechanical properties, such as yield point, tensile strength and elastic modulus, will decrease sharply with the increase of temperature. Therefore, it is very necessary to do grid and steel structure fire prevention.
