The Fire Growth Rate in a Ventilated Tunnel Fire

Abstract

Increasing longitudinal ventilation velocity enhances the heat transfer from hot gases to fuel and then results in an increase of the fire growth rate in a tunnel fire. However, the effect of ventilation on the flame spread and the fire growth rate has not been fully explored. In this paper the relationship between the flame spread and the fire growth rate in a ventilated flow was analyzed theoretically. A large amount of data relevant to the fire growth rate from model and full-scale tunnel fire tests was collected and applied to a detailed analysis of the effect of ventilation on the fire growth rate. The thermal inertia, heat of combustion, the wet perimeter, and the mass burning rate per unit area of the fuel play important roles in the fire growth rate. In addition, the fire growth rate increases linearly with the ventilation velocity. A correlation that fits all the data of the fire growth rate from model and full-scale tunnel fire tests very well was proposed.