After the thick steel structure fireproof coating is sprayed on the surface of steel members, the fire-resistant and heat insulation protective layer is formed by the incombustibility and low thermal conductivity of the coating itself in case of fire, which slows down the direct attack of fire on load-bearing members, Because the thick steel structure fire retardant coating has the characteristics of no corrosion of steel, no chemical reaction with any anti-corrosion primer, no irritating smell, light coating weight (relatively light structure load weight), large unit coating area, no smoke emission and no harmful gas emission, Therefore, it is suitable for fireproof coating and fire protection of steel structure load-bearing members in various new, expanded and rebuilt industrial and civil construction projects
Construction technology of fireproof coating for thick steel structure
1. Before the fire retardant coating is applied, the rust removal and anti rust primer coating on the steel member surface shall meet the design requirements and the current national specifications, and the dust, oil stain and other foreign matters on the steel member surface shall be completely removed
2. Fire retardant coating shall be applied before interior decoration and under the condition that it will not be damaged by subsequent works. During construction, the walls, doors and windows, mechanical equipment and other components that do not need fire protection shall be covered
3. Spray the Dongan steel structure interface agent before spraying. After the interface agent is dried, spray or smear the coating. The mixture should be mixed evenly according to the ratio of powder to emulsion =1:1 before coating. The mixture should be made of non caking thick liquid state. The thin consistency should be determined according to the coating method to facilitate construction, no flow and strong bonding. To prevent coating leakage or separation
4. When spraying method is adopted, concave convex bucket type spray gun should be used with air pressure of 0.6-0.8 MPa and nozzle diameter of 6-10 mm
5. The first time of spraying should not be too thick, and the next one should be dry until the thickness specified in the standard is reached
6. The coating method of fire retardant coating is basically the same as that of cement coating
