With the booming of high-rise buildings and the ever-increasing height of buildings, more and more people are paying attention to steel structures because steel structures have high strength, light weight, good seismic performance, short construction period, low basic cost and structural occupation. Many advantages such as small area and high degree of industrialization. However, compared with the concrete structure, a significant weakness of the steel structure is that it is easy to conduct heat. When the surface temperature of the steel reaches 400 °C, the strength and elastic modulus will decrease significantly. When the temperature reaches 600 °C, the strength of the steel for steel structure is almost Zero. The fire resistance of bare steel is usually only 15 to 30 minutes. According to the requirements of China's building fire protection design code, the main load-bearing components of the building, such as the fire resistance limit of columns, beams, walls and floors, are 0.5 to 3.0 hours respectively. Our country has clearly stated that it is necessary to adopt fire prevention measures on the steel structure, and it is necessary to meet the corresponding national standards before passing the acceptance.
There are various fireproof treatment methods for steel structures. In the past, solid concrete outer cladding layers by cast-in-place molding, fire barriers such as refractory bricks, gypsum board coating or internal cooling of hollow pipes were used. Now more is to protect the steel structure by spraying fireproof coating, anticorrosive coating and fluorocarbon paint. Because of the good fireproof and heat insulation performance of this measure, the construction is not restricted by the structural geometry, generally does not need to add auxiliary facilities, and the coating quality is light, and there is a certain aesthetic decorative effect, so it has been widely used.