Smoke extraction experiments in case of fire in a tunnel

Smoke extraction in the case of a fire in a tunnel is investigated here experimentally. Experiments are carried out on a 1:20th tunnel scale model. The tunnel is equipped with two mechanical exhaust ducts, on both sides of the fire source. The influence of their location and the shape of the outlets is studied in the first instance. Next, the exhaust system efficiency is determined for different fire heat release rates, until the value of 100% is achieved which is related to smoke confinement between both ducts.