Fire Safety Science Digital Archive

The behavior of fire-induced smoke layers in a tunnel and a particular station of the Paris Metro, in the presence of ventilating-air flow, is experimentally investigated using small scale models. For practical purposes, laser investigation techniques are utilized. The reverse layer formed near the ceiling of a tunnel, and flowing against the ventilation, is analyzed from the results of the small scale test as a function of the fire source power and ventilation current. A simple modeling procedure is applied which should permit full scale lengths of reverse layers to be deduced. Measurements of temperature distribution, along the tunnel median plane and cross sections, reveal the stratified evolution of the smoke backflow. The experiments with a ventilated tunnel station configuration show the essential characteristics of the smoke movement (entrainment, stratification, recirculation, etc ...). The propagation of hot combustion products, indeed, is of practical importance for fire-fighting and people evacuation.