The pressurized smoke control system in the vestibule is important for fire safety in buildings because it is concerned with egress time of people and the safety of fire fighters. The vestibule pressurization system can prevent smoke from entering the vestibule using differential pressure when fire doors are closed and using the egress velocity when fire doors are open. Air supplying units in the vestibule need to be arranged by taking account of the location of doors and the volume of the vestibule in order to assure the uniform air egress velocity through a fire door when it is open. In this study, computational fluid dynamics (CFD) simulations were conducted for the vestibule where multiple doors are installed and it was found that the reverse flow occurs when the damper position in vestibule is not appropriate. In order to validate numerical analysis results, experiments were conducted to measure the air velocity in the fire door inside the apartment building. It was found that the experimental data were in good with the numerical analysis results.
In the case of interior fire in an apartment building, contamination of vestibule area by fire smoke before air fan operating when fire doors are open makes the evacuation of people very difficult. In order to investigate the effect of Heat Release Rate (HRR) and interior opening on fire flow velocity, numerical simulations using Fire Dynamics Simulator were carried out. In simulations, actual dimensions and configuration of an apartment building were considered and interior leakage and HRR were varied. The results of this study are as follows.
1. The reverse flow occurs when the damper position in vestibule is not appropriate.
2. When the damper in the vestibule is located at the center of the wall opposite to multiple fire doors, the uniform air egress velocity can be obtained.
3. It is important to conduct numerical simulations for the initial design and to ensure the egress safety in high-rise buildings.
4. Fire flow velocity distribution is significantly influenced by HRR and interior opening resulting in the change of the location of a neutral plane. Also, it is shown that there is a larger difference of the fire flow velocity between upper and lower part of the fire door when the neutral plane becomes closer to the ceiling.
5. Fire flow velocity is fluctuated when the opening size is under 0.09 ㎡.
6. Fire flow velocity is over 1.5 m/s when the fire is grown to 1 ㎿. Therefore, it is necessary to increase the magnitude of air egress velocity regulated by the law.