Design Fire Curves

An overview of design fires in tunnels is given. Design fires are obtained from guidelines or standards or exclusively for a specific tunnel project. They can be represented as a single constant design value or as a time-dependent fire curve, given in the form of either heat release rates (HRRs), temperatures or combustion products. Various ways exist to represent a design fire curve for tunnels. These can include different growth rates or combinations of growth rates with constant levels of design maximum values coupled to a decay period. The different types of design fire curves are put into the context of fire development in vehicles and tunnel fire dynamics. Mathematical representations of design fire curves are presented and discussed. An example of a new concept for creating a design fire curve is presented.