Abstract: External steel structures are applied on the suspended structure system of a high-rise building, and some fire protection measures such as fire resistive coating should be used to protect them from fire. However, if these external steel structures are regarded as indoor structures, it will cause waste of resources. Taking a building as an example, the scenes of fire in cantilever truss floor and standard gravity floor were set. The temperature field near the outdoor steel members was calculated and compared with the outdoor standard temperature rise curve of European code. The most negative temperature raise condition was obtained and the stress condition and fire resistance performance of steel components were calculated. Feasible fire protection scheme was put forward and the feasibility and economy of the scheme were verified.

Key words: suspended structure system, external steel structure, fire protection, high-rise building