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The Effect of Heat Release Rate on the Environment of a Subway Station
Available online at www.sciencedirect.com
ScienceDirect
Available online at www.sciencedirect.com Procedia Engineering00 (2017) 000–000
ScienceDirect
www.elsevier.com/locate/procedia
Procedia Engineering 205 (2017) 3717–3720
10th International Symposium on Heating, Ventilation and Air Conditioning, ISHVAC2017, 1922 October 2017, Jinan, China
The Effect of Heat Release Rate on the Environment of a Subway Station Wenjun Leia,b,* , Angui Lic, Chuanmin Taid aa Department of Building Environment and Energy ApplicationEngineering, Shandong Jianzhu University, Jinan, China 250101 Key Laboratory of Renewable Energy Utilization Technologies in Building of the State Ministry of Education, Shandong Jianzhu University, Jinan, China 250101 cc School of Environmental and Municipal Engineering, Xi’an University of Architecture and Technology, Xi’an, Shaanxi 710055, P.R. China dd Shandong Jianzhu University Architecture & Urban Planning Design Institute, Jinan, China 250101
b b
Abstract The characteristics of the fire environment in a subway station under fire situations was investigated in this paper. Visibility, temperature and carbon monoxide at the evacuation stairs in the subway station were computed by Fire Dynamics Simulator (FDS). The effects of different heat release rates on evacuation were discussed respectively. With the increase of heat release rate, evacuation will become even more difficult, and the overall efficiency of evacuation will be lower. Therefore, relevant departments should take preventive measures to prevent fires with large heat release rates from broking out. © 2017 The Authors. Published by Elsevier Ltd. © 2017 The Authors. Published by Elsevier Ltd. Peer-review under responsibility of the scientific committee of the 10th International Symposium on Heating, Ventilation and Air Peer-review under responsibility of the scientific committee of the 10th International Symposium on Heating, Ventilation and Conditioning. Air Conditioning. Keywords: Subway station; Fire heat release rate; Carbon monoxide (CO) concentration; Visibility
1. Introduction Nowadays mass transit has become the key transport means for big cities all over the world [1]. It also develops rapidly for cities in China. In recent years, subway has become one of the most important ways of modernized urban rail transit[2]. However, subway fire in Daegu, Korea, Baku and Azerbaijan caused huge casualties and property losses[3]. Therefore, when the fire breaks out, the issue of whether passengers can safely escape from the subway * *
Corresponding author. Tel.+ 8613808935926. E-mail address: [email protected]; [email protected]
1877-7058 © 2017 The Authors. Published by Elsevier Ltd. Peer-review under responsibility ofthe scientific committee of the 10th International Symposium on Heating, Ventilation and Air Conditioning.
1877-7058 © 2017 The Authors. Published by Elsevier Ltd. Peer-review under responsibility of the scientific committee of the 10th International Symposium on Heating, Ventilation and Air Conditioning. 10.1016/j.proeng.2017.10.301
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Wenjun Lei et al. / Procedia Engineering 205 (2017) 3717–3720 Wenjun Lei et al./ Procedia Engineering00 (2017) 000–000
station or not is a concern. In this paper, LES simulation is performed to study the dispersion of fire-induced buoyancy driven smoke in the subway station. The temperature, carbon monoxide (CO) concentration and visibility in subway station fire are computed by Fire Dynamics Simulator (FDS) ver.5 [4]. 2. Methods 2.1. The physical model The subway station is three-storey underground construction with four lanes, which is shown in Fig.1. The area of this station is about 4600m2. The details of the exits and stairs are shown in Table 1. Table1. The details of the exits and stairs Sizes Structures Number Comment (m) Exits 4 6×2 All of the exits are always open. Normally, the four stairs are used as working stairs. If there is an accident, they will be used as evacuation Stairs 4 14.5×7 stairs.
Fig.1 The geometry of the subway station
2.2. Characteristics of the fire environment As known to all, if the occupants expose in the environment filled with smoke, the speed of the evacuation would be severely[5]. Once there is a fire, a wide range of toxic gases can be generated[6]. Generally, the influence of CO, CO2 and HCN and the deprivation of O2 can be used to analyze the evacuation process [7]. When we stay in the environment filled with smoke, our brain is starved of oxygen. Under this condition, the walking speeds of passengers will gradually reduce. Three kinds of fire with heat release rate of 10MW, 7.5MW and 4MW are studied in this paper. The location of fire source can be seen in Fig.1. And the sizes of these fire source is 1m×1m×1m. And the effect of smoke venting system on evacuation is also investigated in this paper. 2.3. The turbulent airflow model In this paper, FDS is used to predict the environmental characteristics of the fire. This software can be used to predict the heat release rate, CO concentration, temperature and visibility. Fire Dynamics Simulator (FDS) is used to carry out CFD simulations [8]. It is reported LES is able to predict instantaneous flow characteristics and turbulent flow structures, and thus offering much more accurate results. LES is now more widely used and reported to give better predictions on some cases of buoyancy driven flow. Therefore, LES is used here [9]. 2.4. Tenability Criteria for Evacuation The body of an exposed occupant can be regarded as acquiring a “dose” of heat over a period of time. NFPA 130 (2010) provides air temperature which could cause harm to human[10]. If the temperature of the experiment is 80℃，
Wenjun Lei et al. / Procedia Engineering 205 (2017) 3717–3720 Wenjun Lei et al./ Procedia Engineering 00 (2017) 000–000
3719 3
the maximum exposure time of the human is only 3.8 minute. About visibility, the influence of smoke caused by a fire on visibility is significantly important in evacuation, and low visibility could hinder evacuation and result in heavy casualties. Visibility should be at least 10m in order not to hinder evacuation. It indicates that poor visibility could make passengers lose their sense of direction and thus cause heavier casualties [11]. It is recommended that the soot concentration in the smoke should be maintained below 65 mg/m3 which corresponds to 9.114m for the recognition of the luminescent object and 6.096m for the non luminescent object [12]. Therefore, we take 6.096m as the lower limit of the visibility in this paper. NFPA 130 (2010) provides air carbon monoxide content which could cause harm to human[11]. Air carbon monoxide (CO) content is as follows: (1)Maximum of 2000ppm for a few seconds (2)Averaging 1150ppm or less for the first 6minutes of the exposure Therefore, we take 80℃ (temperature), 6.096m (visibility) and 2000ppm (CO concentration) as the critical parameters to passengers’ evacuation. Results and discussion Stairs are the important structures for connecting floors. And they are the only road for evacuation, in this subway station. Therefore, this paper focuses on the environment characters at the stairs in subway station, when the fire breaks out. Thus parameters which affect evacuation are given. The growth of fire is modeled by the power law using an appropriate constant to simulate low, medium, fast, ultra-fast growing fires. The fire source is located in the middle of the platform at 2nd floor (see Fig.1 fire source ). The heat release rate versus time plot for the fire source is also provided for the investigated scenario. The size of these fire sources are all 1m×1m×1m. The heat output from the fire source is determined by the size of fire source and the heat release rate per unit area. A typical ultra-fast t-square growth fire up to steady size of 4, 7.5 [7] and 10MW are employed (Fig.2) in the study to investigate the influence of the fire heat release rates on the evacuation efficiency. CO concentration, temperature and visibility varying with time are also given, which are shown in Fig.3.
Fig.2 Fire curves with ultra-fast t-square growth fire up to steady size of 4, 7.5 and 10MW in the subway station
Fig.3 Fire characteristics of subway station of three different heat release rates fires: (a) predicted variation in CO concentration; (b) predicted variation in temperatures; (c) predicted variation in visibility.
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Wenjun Lei et al. / Procedia Engineering 205 (2017) 3717–3720 Wenjun Lei et al./ Procedia Engineering00 (2017) 000–000
From Fig.3 we can see that the changes of visibility of three kinds of heat release rates are almost the same (i.e. all of the visibilities reduce to 6m after about 210s from the fire breaks out). However, the variations of temperature and CO concentration have big differences. When the heat release rate is 10MW, the visibility is bad, and the temperature and CO concentration rapidly increase. 3. Conclusions The subway has such advantages as large transportation capacity, low pollution, high speed, easy traffic, low energy consumption, low resource occupation and comfort, which are in conformity with the principle of sustainable development. Through this study, we can draw the conclusion that the greater the fire heat release rate, the more difficult to evacuate. Because when the fire heat release rate is greater, the visibility is bad. Meanwhile, people have to stand the danger caused by the rapid increase of temperature and CO concentration. These could reduce the evacuation efficiency and easy result in enormous personnel casualties and economic losses. Therefore, relevant departments should take preventive measures to prevent fires with large heat release rates from broking out. And arson should also be avoided to protect the safety of persons and property. Acknowledgements This research project is sponsored by Natural Science Foundation of Shandong Province (BS2015SF011), Construction Fund of Co-Innovation Center of Green Building (LSXT201520) and the Doctoral Scientific Fund Project of Shandong Jianzhu University(XNBS1409). References [1]Miclea,P.C.,Chow,W.K.,Chien,S.W., Li,J., Kashef,A.H., Kang,K., 2007. International tunnel fire-safety design practices. ASHRAE Journal 2007, 50–60. August. [2]Jae Seong Roh, Hong Sun Ryou, Won Hee Park, Yong Jun Jang. CFD simulation and assessment of life safety in a subway train fire. Tunneling and Underground Space Technology 2009; 24: 447–453. [3]I.J. Duckworth. Fires in vehicular tunnels. 12th U.S./North American Mine Ventilation Symposium 2008. [4]McGrattan, K.,Baum, H.,Rehm, R.,Hostikka, S.,Floyd,J.(Eds.), 2007.Fire Dynamics Simulator (Version5) -Technical Reference Guide. NISTS pecial Publication 1018-5, BFRL,NIST. [5]P.G. Holborn, P.F. Nolan, J. Golt, An analysis of fatal unintentional dwelling fires investigated by London Fire Brigade between 1996 and 2000, Fire Safety Journal 38/1 (2003) 1–42. [6]E.G. Butcher, A.C. Parnel, Fire Control in Fire Safety Design, London, England, E. & F. N. Spon Ltd, 1979. [7]Yanfu Wang, Juncheng Jiang, Dezhi Zhu. Full-scale experiment research and theoretical study for fires in tunnels with roof openings. Fire Safety Journal 44 (2009) 339–348. [8]K.B. McGrattan, Fire Dynamics Simulator (Version 4.07) - Technical Reference Guide. NIST Special Publication 1018, National Institute of Standards and Technology, Gaithersburg, MD, 2006. [9]P.A. Friday, F.W. Mowrer, Comparison of FDS Model Predictions with FM/SNL Fire Test Data. NISTGCR01-810, National Institute of Standards and Technology, Gaithersburg, MD, 2001. [10]NFPA130 Standard for Fixed Guideway Transit and Passenger Rail Systems, 2010. [11]Won-Hee Park, Dong Hyeon Kim, Hee-Chul Chang. Tunnelling and Underground Space Technology, 2006. [12]Dong-Ho Rie, Myung-Whan Hwang, Seong-Jung Kim, Sung-Wook Yoon, Jae-Woong Ko, Ha-Yong Kim. A Study of Optimal Vent Mode for the Smoke Control of Subway Station Fire, Tunnelling and Underground Space Technology, 2006.
ScienceDirect
Available online at www.sciencedirect.com Procedia Engineering00 (2017) 000–000
ScienceDirect
www.elsevier.com/locate/procedia
Procedia Engineering 205 (2017) 3717–3720
10th International Symposium on Heating, Ventilation and Air Conditioning, ISHVAC2017, 1922 October 2017, Jinan, China
The Effect of Heat Release Rate on the Environment of a Subway Station Wenjun Leia,b,* , Angui Lic, Chuanmin Taid aa Department of Building Environment and Energy ApplicationEngineering, Shandong Jianzhu University, Jinan, China 250101 Key Laboratory of Renewable Energy Utilization Technologies in Building of the State Ministry of Education, Shandong Jianzhu University, Jinan, China 250101 cc School of Environmental and Municipal Engineering, Xi’an University of Architecture and Technology, Xi’an, Shaanxi 710055, P.R. China dd Shandong Jianzhu University Architecture & Urban Planning Design Institute, Jinan, China 250101
b b
Abstract The characteristics of the fire environment in a subway station under fire situations was investigated in this paper. Visibility, temperature and carbon monoxide at the evacuation stairs in the subway station were computed by Fire Dynamics Simulator (FDS). The effects of different heat release rates on evacuation were discussed respectively. With the increase of heat release rate, evacuation will become even more difficult, and the overall efficiency of evacuation will be lower. Therefore, relevant departments should take preventive measures to prevent fires with large heat release rates from broking out. © 2017 The Authors. Published by Elsevier Ltd. © 2017 The Authors. Published by Elsevier Ltd. Peer-review under responsibility of the scientific committee of the 10th International Symposium on Heating, Ventilation and Air Peer-review under responsibility of the scientific committee of the 10th International Symposium on Heating, Ventilation and Conditioning. Air Conditioning. Keywords: Subway station; Fire heat release rate; Carbon monoxide (CO) concentration; Visibility
1. Introduction Nowadays mass transit has become the key transport means for big cities all over the world [1]. It also develops rapidly for cities in China. In recent years, subway has become one of the most important ways of modernized urban rail transit[2]. However, subway fire in Daegu, Korea, Baku and Azerbaijan caused huge casualties and property losses[3]. Therefore, when the fire breaks out, the issue of whether passengers can safely escape from the subway * *
Corresponding author. Tel.+ 8613808935926. E-mail address: [email protected]; [email protected]
1877-7058 © 2017 The Authors. Published by Elsevier Ltd. Peer-review under responsibility ofthe scientific committee of the 10th International Symposium on Heating, Ventilation and Air Conditioning.
1877-7058 © 2017 The Authors. Published by Elsevier Ltd. Peer-review under responsibility of the scientific committee of the 10th International Symposium on Heating, Ventilation and Air Conditioning. 10.1016/j.proeng.2017.10.301
3718 2
Wenjun Lei et al. / Procedia Engineering 205 (2017) 3717–3720 Wenjun Lei et al./ Procedia Engineering00 (2017) 000–000
station or not is a concern. In this paper, LES simulation is performed to study the dispersion of fire-induced buoyancy driven smoke in the subway station. The temperature, carbon monoxide (CO) concentration and visibility in subway station fire are computed by Fire Dynamics Simulator (FDS) ver.5 [4]. 2. Methods 2.1. The physical model The subway station is three-storey underground construction with four lanes, which is shown in Fig.1. The area of this station is about 4600m2. The details of the exits and stairs are shown in Table 1. Table1. The details of the exits and stairs Sizes Structures Number Comment (m) Exits 4 6×2 All of the exits are always open. Normally, the four stairs are used as working stairs. If there is an accident, they will be used as evacuation Stairs 4 14.5×7 stairs.
Fig.1 The geometry of the subway station
2.2. Characteristics of the fire environment As known to all, if the occupants expose in the environment filled with smoke, the speed of the evacuation would be severely[5]. Once there is a fire, a wide range of toxic gases can be generated[6]. Generally, the influence of CO, CO2 and HCN and the deprivation of O2 can be used to analyze the evacuation process [7]. When we stay in the environment filled with smoke, our brain is starved of oxygen. Under this condition, the walking speeds of passengers will gradually reduce. Three kinds of fire with heat release rate of 10MW, 7.5MW and 4MW are studied in this paper. The location of fire source can be seen in Fig.1. And the sizes of these fire source is 1m×1m×1m. And the effect of smoke venting system on evacuation is also investigated in this paper. 2.3. The turbulent airflow model In this paper, FDS is used to predict the environmental characteristics of the fire. This software can be used to predict the heat release rate, CO concentration, temperature and visibility. Fire Dynamics Simulator (FDS) is used to carry out CFD simulations [8]. It is reported LES is able to predict instantaneous flow characteristics and turbulent flow structures, and thus offering much more accurate results. LES is now more widely used and reported to give better predictions on some cases of buoyancy driven flow. Therefore, LES is used here [9]. 2.4. Tenability Criteria for Evacuation The body of an exposed occupant can be regarded as acquiring a “dose” of heat over a period of time. NFPA 130 (2010) provides air temperature which could cause harm to human[10]. If the temperature of the experiment is 80℃，
Wenjun Lei et al. / Procedia Engineering 205 (2017) 3717–3720 Wenjun Lei et al./ Procedia Engineering 00 (2017) 000–000
3719 3
the maximum exposure time of the human is only 3.8 minute. About visibility, the influence of smoke caused by a fire on visibility is significantly important in evacuation, and low visibility could hinder evacuation and result in heavy casualties. Visibility should be at least 10m in order not to hinder evacuation. It indicates that poor visibility could make passengers lose their sense of direction and thus cause heavier casualties [11]. It is recommended that the soot concentration in the smoke should be maintained below 65 mg/m3 which corresponds to 9.114m for the recognition of the luminescent object and 6.096m for the non luminescent object [12]. Therefore, we take 6.096m as the lower limit of the visibility in this paper. NFPA 130 (2010) provides air carbon monoxide content which could cause harm to human[11]. Air carbon monoxide (CO) content is as follows: (1)Maximum of 2000ppm for a few seconds (2)Averaging 1150ppm or less for the first 6minutes of the exposure Therefore, we take 80℃ (temperature), 6.096m (visibility) and 2000ppm (CO concentration) as the critical parameters to passengers’ evacuation. Results and discussion Stairs are the important structures for connecting floors. And they are the only road for evacuation, in this subway station. Therefore, this paper focuses on the environment characters at the stairs in subway station, when the fire breaks out. Thus parameters which affect evacuation are given. The growth of fire is modeled by the power law using an appropriate constant to simulate low, medium, fast, ultra-fast growing fires. The fire source is located in the middle of the platform at 2nd floor (see Fig.1 fire source ). The heat release rate versus time plot for the fire source is also provided for the investigated scenario. The size of these fire sources are all 1m×1m×1m. The heat output from the fire source is determined by the size of fire source and the heat release rate per unit area. A typical ultra-fast t-square growth fire up to steady size of 4, 7.5 [7] and 10MW are employed (Fig.2) in the study to investigate the influence of the fire heat release rates on the evacuation efficiency. CO concentration, temperature and visibility varying with time are also given, which are shown in Fig.3.
Fig.2 Fire curves with ultra-fast t-square growth fire up to steady size of 4, 7.5 and 10MW in the subway station
Fig.3 Fire characteristics of subway station of three different heat release rates fires: (a) predicted variation in CO concentration; (b) predicted variation in temperatures; (c) predicted variation in visibility.
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Wenjun Lei et al. / Procedia Engineering 205 (2017) 3717–3720 Wenjun Lei et al./ Procedia Engineering00 (2017) 000–000
From Fig.3 we can see that the changes of visibility of three kinds of heat release rates are almost the same (i.e. all of the visibilities reduce to 6m after about 210s from the fire breaks out). However, the variations of temperature and CO concentration have big differences. When the heat release rate is 10MW, the visibility is bad, and the temperature and CO concentration rapidly increase. 3. Conclusions The subway has such advantages as large transportation capacity, low pollution, high speed, easy traffic, low energy consumption, low resource occupation and comfort, which are in conformity with the principle of sustainable development. Through this study, we can draw the conclusion that the greater the fire heat release rate, the more difficult to evacuate. Because when the fire heat release rate is greater, the visibility is bad. Meanwhile, people have to stand the danger caused by the rapid increase of temperature and CO concentration. These could reduce the evacuation efficiency and easy result in enormous personnel casualties and economic losses. Therefore, relevant departments should take preventive measures to prevent fires with large heat release rates from broking out. And arson should also be avoided to protect the safety of persons and property. Acknowledgements This research project is sponsored by Natural Science Foundation of Shandong Province (BS2015SF011), Construction Fund of Co-Innovation Center of Green Building (LSXT201520) and the Doctoral Scientific Fund Project of Shandong Jianzhu University(XNBS1409). References [1]Miclea,P.C.,Chow,W.K.,Chien,S.W., Li,J., Kashef,A.H., Kang,K., 2007. International tunnel fire-safety design practices. ASHRAE Journal 2007, 50–60. August. [2]Jae Seong Roh, Hong Sun Ryou, Won Hee Park, Yong Jun Jang. CFD simulation and assessment of life safety in a subway train fire. Tunneling and Underground Space Technology 2009; 24: 447–453. [3]I.J. Duckworth. Fires in vehicular tunnels. 12th U.S./North American Mine Ventilation Symposium 2008. [4]McGrattan, K.,Baum, H.,Rehm, R.,Hostikka, S.,Floyd,J.(Eds.), 2007.Fire Dynamics Simulator (Version5) -Technical Reference Guide. NISTS pecial Publication 1018-5, BFRL,NIST. [5]P.G. Holborn, P.F. Nolan, J. Golt, An analysis of fatal unintentional dwelling fires investigated by London Fire Brigade between 1996 and 2000, Fire Safety Journal 38/1 (2003) 1–42. [6]E.G. Butcher, A.C. Parnel, Fire Control in Fire Safety Design, London, England, E. & F. N. Spon Ltd, 1979. [7]Yanfu Wang, Juncheng Jiang, Dezhi Zhu. Full-scale experiment research and theoretical study for fires in tunnels with roof openings. Fire Safety Journal 44 (2009) 339–348. [8]K.B. McGrattan, Fire Dynamics Simulator (Version 4.07) - Technical Reference Guide. NIST Special Publication 1018, National Institute of Standards and Technology, Gaithersburg, MD, 2006. [9]P.A. Friday, F.W. Mowrer, Comparison of FDS Model Predictions with FM/SNL Fire Test Data. NISTGCR01-810, National Institute of Standards and Technology, Gaithersburg, MD, 2001. [10]NFPA130 Standard for Fixed Guideway Transit and Passenger Rail Systems, 2010. [11]Won-Hee Park, Dong Hyeon Kim, Hee-Chul Chang. Tunnelling and Underground Space Technology, 2006. [12]Dong-Ho Rie, Myung-Whan Hwang, Seong-Jung Kim, Sung-Wook Yoon, Jae-Woong Ko, Ha-Yong Kim. A Study of Optimal Vent Mode for the Smoke Control of Subway Station Fire, Tunnelling and Underground Space Technology, 2006.