A new design criterion of fire ventilation for transversely ventilated tunnels

Abstract

In this article, the smoke propagation characteristics of transversely ventilated tunnel are examined computationally as a function of fire size and airflow rates of supply and exhaust. Computer simulation using the FDS (Fire Dynamic Simulator) is performed with a 12-m long scale model of the Memorial tunnel with a scale down ratio of the cross section of 1/20. The simulation results are compared with the previous model experimental results and show the good agreement with the experimental ones. It is identified that the computer simulation could be a useful tool to investigate the various features of smoke propagation in transversely ventilated tunnels. It is found that smoke propagating distance increases with fire size and decreases with exhaust ventilation rate and that smoke mixing and descent inducing a hazardous situation is enhanced with supply ventilation rate. The results suggest that the smoke propagating distance and the smoke descent with ventilation rates of supply and exhaust may serve as good criteria in the fire safety design of transversely ventilated tunnels. (A) This paper was presented at Safety in the underground space - Proceedings of the ITA-AITES 2006 World Tunnel Congress and the 32nd ITA General Assembly, Seoul, Korea, 22-27 April 2006. For the covering abstract see ITRD E129148. Reprinted with permission from Elsevier.