Determination of sprinkler system reliability and its effect on structural fire design of steel structures

Automatic sprinkler systems are an effective way to reduce the risk of fire events in buildings. The systems have demonstrated very high operational reliability and design regulations have opened up new opportunities to incorporate sprinklers in building design. It has been shown that in many cases the amount of passive protection of steel members can be reduced significantly or even be left out, if the sprinkler system operates as designed. For robust and fire safe design solutions, it is of great importance that the sprinkler reliability levels and the performance-based design methods used are well justified. Tampere University of Technology has carried out research to determine sprinkler system reliability levels in typical building projects and to estimate the benefits of incorporating system reliability in structural fire design of steel structures. A fire design approach based on the current fire regulations in Finland is introduced and applied to a steel framed shopping mall design. The case study demonstrates how the sprinkler reliability can be taken into account in performance based structural fire design and what is the effect of the reliability on the amount of passive fire protection and cost of the structures.