Probabilistic Safety Concept for Fire Safety Engineering based on Natural Fires

In Germany the regulations for structural fire protection design are based on the “prescriptive rules” in the building codes of the states. The requirements evolved on the basis of long-term experience and seem to be safe enough. But no homogeneous safety level exists for different types of buildings and occupancies. Therefore a comprehensive and well balanced safety concept is needed which is based on generally accepted safety objectives and performance criteria and which includes the effects of fire protection systems, too. In order to guarantee a required reliability of the design, the stochastic variations of the relevant parameters as well as the availability of the fire protection systems on demand have to be taken into account. Using such kind of probabilistic information, it is possible to analyse alternative fire protection concepts, to determine the resulting reliability and to compare it with the required reliability. As a result appropriate safety formats for the different fire safety verification methods shall be derived in the near future. For structural fire design this safety concept is planned to be included in the national annex to Eurocode 1 part 1-2 and also in the German guideline for fire safety engineering.