Prediction of the lining temperatures in a road tunnel in the event of a serious vehicle fire

Cast iron linings are used in the construction of many road tunnels. The linings are generally covered by architectural panelling which stands proud of the surface of the cast iron. A calculation method is developed for determining the behaviour of the temperatures in the lining of a tunnel, incorporating cast iron segments, when subject to the heat released from a fire. The prediction method is applied to determine the temperatures in the various layers when exposed to a fire with a peak heat release rate of 170MW. It is shown that the temperatures in the cast iron flanges rise to around 560 degrees C which will necessitate their replacement.