Spraying fire retardant coating on steel structure can improve the strength and stability of steel structure at high temperature, improve the bearing capacity of steel structure, and improve the fire resistance of materials.
Fireproof coating is divided into thick layer and thin layer, the thickness of thin coating is less than 7 mm, and the thickness of thick coating is generally 8 ~ 50 mm. Thin coating generally has the property of expansion and foaming, which can absorb heat in case of fire and effectively insulate heat transfer to reduce the temperature rise of steel structure.
Generally, the steel structure is treated with fire-proof coating, including cast-in-place concrete and surface spraying. Concrete has the function of heat conduction, which can effectively slow down the heat conduction, so as to improve the fire performance of steel structure. environmental protection anti-corrosion coating is usually used for protection. Inorganic anti-corrosion materials are mostly used in anti-corrosion coatings, and the reasonable anti-corrosion grade is determined according to the technical parameters such as anti-corrosion form and anti-corrosion performance of fireproof layer. generally, the service life of steel structure surface protection is 10-15 years, the thickness of anti-corrosion coating is at least 240 μ m, the primer, intermediate coating and fabric should have enough adhesion, and the adhesion between primer and steel structure surface is more than or equal to 5MPa. The pull-out method is used for adhesion test to ensure the effectiveness of anti-corrosion coating. It is very important to take fire prevention and anti-corrosion measures for steel structure construction.
