Using the peak heat release rate to determine the fire risk level of road tunnels

A wide range of fire incidents can occur in a road tunnel, e.g. a fire in the cargo compartment of a goods vehicle, carelessness due to discarded smoker's materials or loss of vehicle control, and a crash resulting in a multiple-vehicle fire. The number of possible fire scenarios is numerous and so, for design applications, rather than attempting to analyse every possible event using a deterministic approach, a preliminary analysis using a quantitative risk assessment approach should be considered. This paper presents a risk assessment methodology to identify the possible fire scenarios that can occur in a road tunnel in order to specify design fire requirements for smoke control systems. The analysis considers factors such as legislation, vehicle fuel load, traffic mix in the tunnel, vehicle accident rate, and causes of vehicle ignition.