scope:

Field tests of stairwell and vestibule pressurization systems were performed in a 32-stovy high-rise building. Pressure diferences in the stairwell, and vestibule and average air velocity were tested under various conditions. Test results indicate that indirectpressurization through a stairwell is feasible. Ignoring stack efect, the worst door-opening condition is that thejre doors of the top or bottom three adjoiningfloors of the building are open simultaneously. Pressurization systems in combination with corridor smoke exhaust systems are advantageous in preventing the spread ofsmoke to the escape routes. Tests demonstrate that inappropriate stairwell and vestibule pressurization systems not only fail to ensure safe evacuation but also have serious safety issues.