Longitudinal ventilation systems are commonly installed in new tunnels in big cities of the Far Eastincluding Mainland China, Hong Kong and Taiwan. Many tunnels are found and some of them areinclined at an angle to the horizontal. However, smoke movement in those tilted tunnels is not fullyunderstood. Some longitudinal ventilation was designed based on presumed smoke movementpattern without experimental demonstration.Smoke movement pattern in a tilted tunnel model was studied by scale modeling technique.
Removing smoke at the early stage of a building fire would assist in evacuation. Mechanical smoke extraction systems are commonly installed in larger buildings. In designing such a system, makeup air must be provided to displace the hot smoke.However, air supplied would also provide additional oxygen for combustion. Therefore, it is important to study how air should be supplied. In this paper, the efficiency of mechanical exhaust in anatrium with different arrangements for air supply will be discussed.
For static smoke exhaust systems, such as horizontal ceiling vents, buoyancy of the smoke layer is the driving force for smoke removal. However, wind effect should also be considered, as the smoke layer interface height can be raised up or pulled down, depending on the conditions. Key equations on calculating the smoke exhaust rates and the required vent area will be reviewed first in this paper. Modifications of those equations with wind effects are discussed. An atrium is taken as an
This article presents the difficulty for ASHRAE to take into account the high levels of ventilation requiries and to combine them with the demand for "guidance" encouraged by the tobacco industry and its allies.
This article focuses on the replacement air component for atrium smoke exhaust, including comparisons of three design approaches. The concepts are illustrated by case studies.
This paper describes the smoke control aspects of twonaturally ventilated high-rise office buildings with operable windows. One utilizes its operable windows in conjunction with an HVAC system to provide tenants with fresh air. The other utilizes a series of automatically controlled windows and
vents in conjunction with tenant-controlled windows to provide ventilation. Both buildings, located in San Francisco, were designed under the Uniform Building Code.
Field tests of stairwell and vestibule pressurization systems were performed in a 32-story high-rise building. Pressure differences in the stairwell, and vestibule and average air velocity were tested under various conditions. Test results indicate that indirect pressurization through a stairwell is feasible. Ignoring stack effect, the worst door-opening condition is that the fire doors of the top or bottom three adjoining floors of the building are open simultaneously. Pressurization systems in
This document describes the designing process of a smoke management system for an atrium, using tools going from empirical equations to complex models, in order to have a safe evacuation of occupants in case of fire.
After describing smoke hazards, this document gives for the designers the basic principles of smoke management in atriums. Requirements of the Canadian building code are also described.
2 examples of extract systems are presented in this paper : the first one concerns dust removal in a public waste plant and the second smoke separation in a smoker/non-smoker zone with no visual impact (i.e. no walls).Thanks to the CFD simulation, proper exhaust systems for dust and smoke have been successfully designed and optimised for each case with simulation results. The proposed solutions were then realized and with few minor modifications led to excellent working conditions on the one hand and excellent smoke caption on the other hand.
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