Simple Model for Longitudinal Temperature Distribution of Utility Tunnel Fire with Double Fires and End Wall Fire

Abstract

The enhanced burning intensity of double fires in utility tunnels resulting in accumulated smoke and heat can lead to heavier casualties. For a single fire source with an end wall, the end wall causes reflections of smoke and heat, resulting in interactions similar to those of double fires. The ability to predict the smoke flow and temperature distribution of such a scenario would facilitate design consideration and evacuation plans. This paper proposes a simple model that can estimate the smoke flow and temperature distribution of both cases. The model to describe the interaction in double fires was developed based on the temperature attenuation model of a single fire to include a proposed exponential correction function taking into account the spacing between the fire sources. The concept is based on the fact that the maximum temperature in double fires is greater than that of a single fire and lower than that of the direct superposition of two single fires. The proposed model can estimate the temperature distribution with prediction errors of less than 20%, and requires much less time than traditional finite-element (FE) simulation models. This model can provide information on the temperature distribution of a typical tunnel double fire and wall fire and for quick decision-making if needed.