Abstract: In the actual process of engineering construction, the fire protections for special cases cannot be carried out in accordance with the current code sometimes, and it is necessary to use some alternative fire protection designs. Aiming at the fire protection problem of steel structure in the confined space of a super high-rise building suspended ceiling, this paper puts forward a design scheme of fire protection using "fireproof board + fireproof coating". Meanwhile, the fire protection and heat insulation effect have been experimentally studied by fire test furnace and real fire, and the temperature rise curves of each position of the steel structure under different conditions are obtained. The results indicate that the fire protection and heat insulation effect of 20 mm thick fireproof board installed on the 5 mm thick fireproof coating is better than that of 20 mm thick fireproof coating, which can meet the relevant fire resistance rating requirement in Chinese national standards. The research results provide a new scheme for fire protection design of steel structures in super high-rise buildings.

Key words: super high-rise building, steel structure, fire protection, fire resistance rating