Impacts of Staircase Windows on Pressurized Ventilation System

Abstract Chinese fire prevention codes provided that pressurized ventilation system should be used in the staircase which can not exhaust fire smoke naturally. However, the codes only specified the specific parts of pressurized ventilation and ventilation volume, while they did not specify how to make the pressurized ventilation effective in particular cases. As a result, in engineering application, some staircase pressurized ventilation systems can not effectively prevent smoke entering the staircase. For instance, in a staircase where the pressurized ventilation system must be used according to the codes, opened windows were set in the wall of the staircase so as to facilitate lighting and ventilation. Although that conforms to the codes, the effect of preventing smoke invasion is still unknown. This simulation study focused on the influence of opened windows on the pressurized ventilation system. It was found that if there were no open windows in the staircase, the system worked. At the same time, smoke would flow into the staircase in a short time and the high temperature was fatal to the evacuees if there were opened windows on the wall of this space. These results indicated that opened windows in the staircase would lead to uselessness of the pressurized ventilation system. In conclusion, it was suggested there are no windows in the staircase in which a pressurized ventilation system should be used. And if windows are necessary in the pressurized staircase for light, the windows should be fixed casement windows.