Smoke leakage through wall openings in a fire

This study developed a full-scale smoke-barrier system and established a testing procedure to investigate wall openings of various geometric shapes, which may be passageway for cables and pipes and are usually of irregular shapes, for different pressure differences and temperatures. In addition, a simple analytical model was developed to correlate the experiment data. The results showed that the smoke leakage rate was dependent on several factors, including pressure difference, gas temperature, geometric shape and area of opening. The rate of smoke leakage was proportional to the square root of the pressure difference or to the reciprocal of the square root of the upstream gas temperature. An opening of higher perimeter-to-area ratio had higher resistance against smoke flow and thus allowed smaller rate of smoke leakage. Finally, a geometric loss factor was assigned to the tested wall opening to indicate its smoke leakage characteristics. In the study, the capability of the testing device and the application of the testing procedure were verified to be suitable for the fire tests of more complicate objects, such as smoke barriers or doors, in the future.