Performance Of Smoke Control Systems Research Articles

An effective and efficient approach for smoke control in underground parking garages

Underground parking garages are enclosed spaces not directly exposed to the exterior. A smoke control system is typically required to facilitate occupants’ safe evacuation/relocation and assist in firefighting/rescue. Currently, there is a lack of guidelines for designing such systems in primary codes/standards. Only a limited number of local authorities have developed amendments to address this issue. These amendments either rely on outdated approaches, such as air change method, or simply repurpose carbon monoxide ventilation systems for smoke control without conducting additional engineering analysis and providing justification. The intent of this study is to examine the adopted approaches and explore an effective and efficient approach for garage smoke control. According to the study’s findings, it is discovered that garage floor height significantly impacts the performance of smoke control system. Additionally, structural components (beams) also influence the performance of smoke control system. Moreover, this study derives a linear equation to ascertain available safe egress time (ASET) when utilizing the carbon monoxide ventilation system or typical air change methods. Taking cost into consideration, the study concludes that for effective and cost-efficient smoke control in large underground garages, employing a carbon monoxide ventilation system is preferable to the traditional or equivalent air change method.

Performance Analysis of Smoke Control Systems for Elevators based on Pressurization Method

The pressurization of emergency or evacuation elevator shafts or duct systems during installation is used for smoke control. In this study, the performance of smoke control systems applied to emergency and evacuation elevators were compared and analyzed using the airflow network analysis program CONTAM 3.2. Under the stack effect condition (temperature difference of 30 ℃), the differential pressure formed in the vestibule was analyzed by adjusting the air volume by changing the value of the loss coefficient factor of the automatic pressure smoke damper. In the case of the duct pressurization method, the air flow in the lower floor was introduced to the elevator shaft owing to the duct pressure and the airflow in the upper floors was from the elevator shaft out to the elevator lobby. In the case of the elevator shaft pressurization method, the pressurized air passing through vestibule from the elevator shaft created a differential pressure at the fire door of vestibule. To maintain the differential pressure in the lower floor, relatively more relief dampers should be installed in the upper floors as compared to those in the duct pressurization method.

Relationship between Designed Fire and Performance of Smoke-Control System in a Living Room

The effects of the size of a designed fire on the ventilation system of an adjacent zone is estimated in this study based on a visibility requirement of 5 m in a non-fire zone at 600 s after ignition. To verify the adequacy of the fire dynamics simulator (FDS) input file, smoke movement and ceiling temperature under the hot smoke test conditions of AS4391-1999 were compared with those from the FDS results. The average temperatures measured at 12 locations were within the range of ± 2σ, with the exception of one point, and predicted smoke movement adequately. The size of the designed fire was analyzed in terms of the air volume conditions of the NFSC 501 for a heat release rate (HRR) of 1650 kW (air supply and exhaust at 45,000 cubic meters per hour (CMH)) as well as air volume conditions for a HRR of 1100 kW (air supply at 35,606 CMH and exhaust at 32,506 CMH). It was determined that one of the major factors influencing the required safety egress time was the mixture of downdraft airflow from the diffusers and smoke layer crossing the ventilation boundary.

Numerical study on the effect of elevator movement on pressure difference between vestibule and living room in high-rise buildings

In this study, we experimentally and numerically investigated the effect of elevator movement on the pressure difference between vestibule and living room regulated by the smoke control system in a high-rise building. The elevator and smoke control systems using supplied pressure dampers are considered one of the most important systems for safe evacuation. However, the pressure field and flow rate are strongly disrupted by elevator movement. Thus, they can affect the performance of smoke control systems and hinder evacuation. The experimental results of this study are used to validate the results of the numerical study when elevator is moving at low speed or is stationary. Then, the effect of elevator movement on the pressure difference between the vestibule and living room, which is controlled by the smoke control system, is investigated numerically using ANSYS CFX. The elevator speed is increased from 10 to 70 m/s, corresponding to the real elevator speed increase of 1.5 to 10 m/s based on Reynolds similarity. It is found that the higher the elevator speed, the greater the pressure difference between the vestibule and living room. This shows that the airflow rate should be actively changed by considering the location of the elevator and its speed. The empirical correlation between elevator movement and pressure difference is derived.

A Study on the Development of Dual Mode Damper for Flow Control of Smoke Control Room

In this study, the fire mode and evacuation mode were classified according to the door opening and closing situation of smoke control room in order to improve the problems of the existing smoke control systems, satisfy of the fire safety standards and maximize the performance of smoke control systems. The dual mode damper was developed to control flow in smoke control room by controlling flow of fan according to these modes. The development damper was tested for their performance. For fire mode, the flow control of smoke control room was able to maintain the allowable pressure differential required by the fire safety standard by only about 55% design flow of fan. For escape mode, the flow control of smoke control room is verified by using the design flow 90.5% of fan, so that the dual mode damper is useful for flow control of smoke control room. In addition, the study has acquired the original technology for a dual mode damper. Keywords: Dual Mode Damper, Flow Control, Fire Mode, Escape Mode, Smoke Control

The effect of damper leakage and fire size on the performance of smoke control system in high-rise building

The major function of smoke control system is to prevent smoke from penetrating to vertical shaft or stairwell by pressurizing vestibule where is generally located between the vertical shaft and living room. Thus, it is important to calculate the required flow rate of air supply for remaining the pressure difference of 40 ~ 60 Pa between the shaft and vestibule. Heat and mass transfer from fire plume and leaking flows among building structures are representative influence factors on the flow rate. The previous studies, however, focused on calculation of the flow rate of air supply without considering the fire effect and damper leakage. In this study, the effect of damper leakage and fire size on the performance of smoke control system was investigated when considering various parameters, i.e., building size and pressurizing method. The effective damper leakage area was measured in a wind tunnel and used to numerical analysis for parameter study. As the results, in the case of whole floor pressurizing method, the increase rate of the flow rate is about two times than that of the parted floor pressurizing method. Also, the pressure difference steeply decreases at the fire floor whereas it slightly increases at the other floors as the fire size increases.

재실자 피난안전을 고려한 지하대공간 제연용량 산정에 관한 연구

본 연구를 통해 대공간 건축물에서 화재가 발생하였을 때 국내 화재안전기준에 의한 제연설비가 재실자의 피난시간을 충분히 확보해 주고 있는지 검토하였다. 이를 위해 실존하는 대형 지하 쇼핑몰을 수치해석 모델링하였고 실제의 화재하중 조건과 동일하게 구성하기 위하여 쇼핑몰에 입주한 각 상점의 업종 및 내부에 적재된 가연물을 조사하였다. 조사된 실제의 가연물을 분석하여 업종별 표준화재하중을 산출하였다. 국내 화재안전기준에 의한 제연설비의 효과를 비교하기 위하여 제연용량에 따른 대공간 쇼핑몰의 11개 제연 시나리오를 작성하였으며 각 시나리오에 대한 화재확산과 재실자의 피난행동을 수치해석하였다. 수치해석의 결과를 비교하기 위해 총 열방출량, Flash-over 발생시간, 실내에 잔류하는 soot의 양, 피난실패 및 사망자 수를 분석하여 최적의 제연용량을 도출하였다. In this study, we reviewed the performance of smoke control system by national fire safety code to secure evacuation time of occupants in case of a fire in large enclosure structures. Towards this end, we performed numerical analysis modeling of the existing large underground shopping mall and investigated types of business and combustibles loaded inside the stores situated at the shopping mall to fulfill the same configuration requirements with actual fire load conditions. To compare effects of smoke control system by national fire safety code, we created 11 smoke control scenarios of large enclosure shopping malls according to the ventilation capacity and conducted numerical analysis of evacuation behavior of occupants and the spread of fire against each scenario. In addition, to compare the results of the numerical analysis, we analyzed total heat release amount, flash-over occurrence time, residual amount of soot indoors and the number of evacuation failures and the dead, thereby deducing the optimal ventilation capacity.

Simulation of Atrium Smoke Filling by Computational Fluid Dynamics

Computational Fluid Dynamics (CFD) is evidently relevant to the study of fires, yet the intermediate chemistry has yet to be factored successfully into combustion models. Consequently, predicted airflow patterns, together with pressure and temperature contours, are mostly used in evaluating the performance of smoke control systems. But even using these assumptions, very few studies exist comparing predicted results from CFD with experimental findings. This leaves research with a paucity of data on how smoke is likely to spread, fill and be controlled in large halls.While hot smoke tests in a hall in Japan have yielded good’–quality experimental data for smoke layer interface heights, the dominant approach to hazard assessment on big projects in East Asia is to use a software Fire Dynamics Simulator (FDS) developed at the National Institute of Standards and Technology in the USA. In this paper, FDS predicted results for smoke filling and exhaust will be examined side’–by’–side with experimental data. Our technique is to compare recorded transient smoke layer interface heights with the results predicted by FDS.This work also responds to questions on how to determine smoke layer interface height. In addition to the default FDS method (FDS menu), two methods are proposed to determine heights from sharp changes in, respectively, vertical temperature profiles and particle tracking. Functional analysis is applied to justify predictions, with results suggesting that CFD offers fairly good predictions on smoke layer interface height.

Smoke Movement Characteristics And Fire Safety In Subway Stations

Experimental and numerical studies on smoke movement and control in subway stations are presented. The experiments were conducted in three actual stations in service using small methanol pool fires as the fuel to generate data basis to validate and tune numerical models for subway station fires and furthermore to examine the performance of smoke control systems. A control volume smoke movement model has been applied to the stations. The model was first tuned to reproduce the test results for the simplest condition for each station, and was then applied and compared with test results for other test conditions. The model was finally applied to predict smoke movement in the subway stations of more plausible fires. The effective design and functional operation of fire safety measures in subway systems are discussed. Primarily, importance of restriction of heat release rate through either the control of combustibility of lining materials or installation of sprinkler system is pointed out. And it is clarified that arrangement of alternative evacuation routes on either ends of the platform, and appropriate operation of shutters in stairways between the platform and the concourse ensure safe evacuation.

Study on Smoke Movement and Control for Fires in Apartments

The smoke aspects in the escape routes for a three-level apartment are studied using the fire zone model CFAST 2.0. The smoke temperature and smoke layer interface heights in the corridors and staircases are analyzed. Performance of smoke control systems including ceiling vents (vent size of 1–4 m²) and smoke extraction systems (one to six air changes per hour) installed in the staircase are evaluated. Some experimental results reported in the literature are used to compare with the results predicted by this model. Finally, the effect of installing a residential sprinkler was discussed. Simulations on the fire suppression effect of residential sprinkler were performed using the fire protection engineering tool FASTLite with unsteady \it²-fires. A comparison on the heat release rate of the smoke layer temperature for the cases with and without a sprinkler was made.

A Short Note on Using a Time Constant in Specifying Smoke Filling Time in an Atrium Under an Unsteady Fire

A time constant derived from a t-squared fire with the geometry of an atrium is proposed to specify the smoke filling time. The smoke filling pro cesses in 27 atria with volume varying from 2,500 to 35,000 m3 were simulated by the fire zone model CFAST version 2.0. The atria are located adjacent to a "fire" shop at a lower level. Correlation relationships between the smoke filling time and the time constant are derived. Further, performance of smoke control systems in the atria are evaluated.

Smoke management in office buildings

Design considerations for smoke control systems have been addressed by numerous researchers and practicing engineers. However, papers discussing the actual observed performance of smoke control systems are less frequently encountered. The following three papers address the testing of smoke control systems from two perspectives. First, suggested procedures for testing smoke control systems are described relative to test methodology, system parameters requiring evaluation, and measurement systems. Second, the performance of actual systems is described as observed in tests.