The Fire Safety Engineering (FSE) is a multi-discipline aimed to define the fire safety strategy for buildings under fire conditions, in which structural stability and control of fire spread are achieved by providing active and/or passive fire protection. In this paper, the aspects of FSE for the structural safety checks in case of fire are shown with reference to Italian and European standards. FSE requires the choice of a performance level, the definition of design fire scenarios, the choice of heat flows models and several numerical thermo-mechanical analyses. The information provided by a significant research, performed in Europe for open and closed car parks, are used to apply the FSE to the car parks of the new buildings of the C.A.S.E. Project for L’Aquila, characterized by steel columns supporting the seismically isolated superstructure. The results of the application of the FSE approach are reported and discussed in the second part of the paper.