Pub Date : 2014-01-01DOI: 10.3801/iafss.fss.11-361
Hui Wang, H. Sahraoui
A computational fluid dynamic model with full coupling between gaseous and liquid phases is developed to predict buring rates of liquid pool fires in ventilated full-scale tunnel. Rates of fuel release are calculated using predictions of flame feedback to the surface of the pool. A pool fire in tunnel is modelled as an unsteady process, from the time of ignition until convergence to a quasi-steady burning rate. This feedback supports sustained flame above the pool surface and controls the burning rate of the fuel. The numerical model solves three dimensional, time-dependent Navier-Stokes equations, coupled with submodels for soot formation and thermal radiation transfer. Turbulent combustion process is modelled by an Eddy Dissipation Concept (EDC) by using two chemical reaction steps to CO prediction. The numerical model is shown to possess the ability to predict the effect of ventilation on burning rate and the initial growth period in a fullscale tunnel fire. The current study indicates that CO generation is relatively independent of position in the overfire region, and correlated solely as a function of mixture fraction. While no correlation of soot concentrations in terms of the mixture fraction is found. Abundant CO and soot are formed around the fire base, which is later deflected near the tunnel ceiling, and the backflow brings about the toxic products with a noticeable smoke stratification as the airflow velocity is below a critical value.
{"title":"Mathematical Modelling of Pool Fire Burning Rates in a Full- Scale Ventilated Tunnel","authors":"Hui Wang, H. Sahraoui","doi":"10.3801/iafss.fss.11-361","DOIUrl":"https://doi.org/10.3801/iafss.fss.11-361","url":null,"abstract":"A computational fluid dynamic model with full coupling between gaseous and liquid phases is developed to predict buring rates of liquid pool fires in ventilated full-scale tunnel. Rates of fuel release are calculated using predictions of flame feedback to the surface of the pool. A pool fire in tunnel is modelled as an unsteady process, from the time of ignition until convergence to a quasi-steady burning rate. This feedback supports sustained flame above the pool surface and controls the burning rate of the fuel. The numerical model solves three dimensional, time-dependent Navier-Stokes equations, coupled with submodels for soot formation and thermal radiation transfer. Turbulent combustion process is modelled by an Eddy Dissipation Concept (EDC) by using two chemical reaction steps to CO prediction. The numerical model is shown to possess the ability to predict the effect of ventilation on burning rate and the initial growth period in a fullscale tunnel fire. The current study indicates that CO generation is relatively independent of position in the overfire region, and correlated solely as a function of mixture fraction. While no correlation of soot concentrations in terms of the mixture fraction is found. Abundant CO and soot are formed around the fire base, which is later deflected near the tunnel ceiling, and the backflow brings about the toxic products with a noticeable smoke stratification as the airflow velocity is below a critical value.","PeriodicalId":12145,"journal":{"name":"Fire Safety Science","volume":"13 1","pages":"361-375"},"PeriodicalIF":0.0,"publicationDate":"2014-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75487779","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2014-01-01DOI: 10.3801/iafss.fss.11-1236
X. Ni, W. Chow, Shaogang Zhang, Mei Zhao, Zhongkui Zheng, Xishi Wang
Application of 2-bromo-3,3,3-trifluoropropene (BTP) with water mist in suppressing deep seated wood crib fires was reported in this paper. Performance of the combination of the two clean fire suppressants was examined by laboratory scale experiments and compared with water mist and BTP used alone. Results showed that coupling of water mist with BTP could extinguish the wood crib fires with high efficiency, in which BTP discharged first could fast extinguish the flame, and the following water mist could cool the wood surface and stop glowing combustion. As a result, a complete fire extinguishment without re-strike was achieved in short time. Furthermore, hydrogen fluoride (HF) acid gas produced in the suppression process was acceptable for the use of water mist in conjunction with BTP.
{"title":"Combining Bromofluoropropene with Water Mist for Suppressing Deep Seated Wood Crib Fires","authors":"X. Ni, W. Chow, Shaogang Zhang, Mei Zhao, Zhongkui Zheng, Xishi Wang","doi":"10.3801/iafss.fss.11-1236","DOIUrl":"https://doi.org/10.3801/iafss.fss.11-1236","url":null,"abstract":"Application of 2-bromo-3,3,3-trifluoropropene (BTP) with water mist in suppressing deep seated wood crib fires was reported in this paper. Performance of the combination of the two clean fire suppressants was examined by laboratory scale experiments and compared with water mist and BTP used alone. Results showed that coupling of water mist with BTP could extinguish the wood crib fires with high efficiency, in which BTP discharged first could fast extinguish the flame, and the following water mist could cool the wood surface and stop glowing combustion. As a result, a complete fire extinguishment without re-strike was achieved in short time. Furthermore, hydrogen fluoride (HF) acid gas produced in the suppression process was acceptable for the use of water mist in conjunction with BTP.","PeriodicalId":12145,"journal":{"name":"Fire Safety Science","volume":"59 1","pages":"1236-1246"},"PeriodicalIF":0.0,"publicationDate":"2014-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75582020","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2014-01-01DOI: 10.3801/iafss.fss.11-234
W. An, H. Xiao, Jinhua Sun, K. Liew, W. Yan, Y. Zhou, L. Jiang, X. Huang
To study the effects of sample width and sidewalls on downward flame spread over extruded polystyrene (XPS) slabs, a series of laboratory-scale experiments were conducted. Flame shape, flame spread rate, mass loss rate and temperature were recorded. For XPS without sidewalls, the average maximum flame height (H) and average flame area per unit of width (A/w) rise linearly with an increase in sample width (w) and mass loss rate per unit of width. When sidewalls are absent, flame spread rate first drops and then rises with an increase in width. This trend is determined by gas-phase heat transfer. When sidewalls are present, flame spread rate increases with a rise in width, and solid-phase heat conduction determines the trend. Sidewall effects are comprised of four aspects: oxygen concentration near the sidewalls and gypsum board is low, which leads to reduced flame heat flux; upward and front air flow is intensified; the flame is stretched, and the surface flame is weakened; and molten XPS mass decreases. For narrow samples, H and A/w with sidewalls are higher than those without sidewalls, while the reverse was observed in wider samples. The mass loss rate, preheating length and average flame spread rate with sidewalls are smaller than those obtained without sidewalls. Flame spread acceleration with sidewalls occurs at a broader width than that without sidewalls. The experimental results agree well with the theoretical analysis.
{"title":"Effects of Sample Width and Sidewalls on Downward Flame Spread over XPS Slabs","authors":"W. An, H. Xiao, Jinhua Sun, K. Liew, W. Yan, Y. Zhou, L. Jiang, X. Huang","doi":"10.3801/iafss.fss.11-234","DOIUrl":"https://doi.org/10.3801/iafss.fss.11-234","url":null,"abstract":"To study the effects of sample width and sidewalls on downward flame spread over extruded polystyrene (XPS) slabs, a series of laboratory-scale experiments were conducted. Flame shape, flame spread rate, mass loss rate and temperature were recorded. For XPS without sidewalls, the average maximum flame height (H) and average flame area per unit of width (A/w) rise linearly with an increase in sample width (w) and mass loss rate per unit of width. When sidewalls are absent, flame spread rate first drops and then rises with an increase in width. This trend is determined by gas-phase heat transfer. When sidewalls are present, flame spread rate increases with a rise in width, and solid-phase heat conduction determines the trend. Sidewall effects are comprised of four aspects: oxygen concentration near the sidewalls and gypsum board is low, which leads to reduced flame heat flux; upward and front air flow is intensified; the flame is stretched, and the surface flame is weakened; and molten XPS mass decreases. For narrow samples, H and A/w with sidewalls are higher than those without sidewalls, while the reverse was observed in wider samples. The mass loss rate, preheating length and average flame spread rate with sidewalls are smaller than those obtained without sidewalls. Flame spread acceleration with sidewalls occurs at a broader width than that without sidewalls. The experimental results agree well with the theoretical analysis.","PeriodicalId":12145,"journal":{"name":"Fire Safety Science","volume":"46 1","pages":"234-247"},"PeriodicalIF":0.0,"publicationDate":"2014-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86488639","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2014-01-01DOI: 10.3801/iafss.fss.11-758
Tomoaki Nishino, Hidekazu Suzuki, T. Tsuchihashi
This paper describes an effort to model the heat release rate curve of a tsunami fire. A tsunami fire is defined as a fire that breaks out in coastal areas inundated by a tsunami following an earthquake. Tsunami fires may result in the ignition of tsunami refuge buildings. One type of tsunami fire is a fire where fuel oil spilled from tanks and an enormous amount of debris such as timber, broken houses and expanded polystyrene are burning together on the sea surface. We conducted basic combustion experiments for this type of fire using a pool with a size of 600 mm square where heat release rates were measured by varying the types of debris and the exposed surface areas of fuel oil. Furthermore, a model for heat release rate at the fully developed phase and time to the beginning of fire decay was proposed. The predictions of the proposed model are shown to be more conservative in comparison with the experimental data.
{"title":"Basic Experiment on the Heat Release Property of a Tsunami Fire Fueled by Debris and Fuel Oil Spilled on the Sea Surface Following Tsunami","authors":"Tomoaki Nishino, Hidekazu Suzuki, T. Tsuchihashi","doi":"10.3801/iafss.fss.11-758","DOIUrl":"https://doi.org/10.3801/iafss.fss.11-758","url":null,"abstract":"This paper describes an effort to model the heat release rate curve of a tsunami fire. A tsunami fire is defined as a fire that breaks out in coastal areas inundated by a tsunami following an earthquake. Tsunami fires may result in the ignition of tsunami refuge buildings. One type of tsunami fire is a fire where fuel oil spilled from tanks and an enormous amount of debris such as timber, broken houses and expanded polystyrene are burning together on the sea surface. We conducted basic combustion experiments for this type of fire using a pool with a size of 600 mm square where heat release rates were measured by varying the types of debris and the exposed surface areas of fuel oil. Furthermore, a model for heat release rate at the fully developed phase and time to the beginning of fire decay was proposed. The predictions of the proposed model are shown to be more conservative in comparison with the experimental data.","PeriodicalId":12145,"journal":{"name":"Fire Safety Science","volume":"24 1","pages":"758-768"},"PeriodicalIF":0.0,"publicationDate":"2014-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87553745","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2014-01-01DOI: 10.3801/iafss.fss.11-883
X. Qian, Q. Tai, Yuan Hu, R. Yuen, T. Chee
A novel monomer containing phosphorus and nitrogen (EBAPP) has been synthesized by allowing phenyl dichlorophosphate to react with ethylenediamine and 2-hydroxyethyl acrylate (HEA). The structure of EBAPP was characterized by FTIR, 1 H NMR and 31 P NMR. A series of flame-retardant resins was obtained by blending EBAPP with epoxy acrylate (EA) in different ratios and exposing to the UV-light. The flame-retardant properties of the resins were characterized by the limiting oxygen index (LOI) and microscale combustion calorimeter (MCC). The results showed that the incorporation of EBAPP into EA could improve the flame retardancy of EA. The thermal properties of the resins were investigated by thermogravimetric analysis (TGA) in air atmosphere, indicating that EBAPP could improve the char residues at high temperature. Moreover, the thermal degradation of EA/EBAPP resins were investigated by the real-time fourier transform infrared spectra (RTIR) and thermogravimetric analysis/infrared spectrometry (TGA-IR) analysis. The morphologies of the formed chars were observed by scanning electron microscopy (SEM), demonstrating that 20 wt% of EBAPP in EA exhibited the most effective flame retardancy due to the dense char layers formed during combustion.
{"title":"Thermal degradation and flame-retardant properties of epoxy acrylate resins modified with a novel flame retardant containing phosphorous and nitrogen","authors":"X. Qian, Q. Tai, Yuan Hu, R. Yuen, T. Chee","doi":"10.3801/iafss.fss.11-883","DOIUrl":"https://doi.org/10.3801/iafss.fss.11-883","url":null,"abstract":"A novel monomer containing phosphorus and nitrogen (EBAPP) has been synthesized by allowing phenyl dichlorophosphate to react with ethylenediamine and 2-hydroxyethyl acrylate (HEA). The structure of EBAPP was characterized by FTIR, 1 H NMR and 31 P NMR. A series of flame-retardant resins was obtained by blending EBAPP with epoxy acrylate (EA) in different ratios and exposing to the UV-light. The flame-retardant properties of the resins were characterized by the limiting oxygen index (LOI) and microscale combustion calorimeter (MCC). The results showed that the incorporation of EBAPP into EA could improve the flame retardancy of EA. The thermal properties of the resins were investigated by thermogravimetric analysis (TGA) in air atmosphere, indicating that EBAPP could improve the char residues at high temperature. Moreover, the thermal degradation of EA/EBAPP resins were investigated by the real-time fourier transform infrared spectra (RTIR) and thermogravimetric analysis/infrared spectrometry (TGA-IR) analysis. The morphologies of the formed chars were observed by scanning electron microscopy (SEM), demonstrating that 20 wt% of EBAPP in EA exhibited the most effective flame retardancy due to the dense char layers formed during combustion.","PeriodicalId":12145,"journal":{"name":"Fire Safety Science","volume":"27 1","pages":"883-894"},"PeriodicalIF":0.0,"publicationDate":"2014-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85490058","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2014-01-01DOI: 10.3801/iafss.fss.11-1261
Ralf Hetzer, F. Kümmerlen, K. Wirz, D. Blunk
The most effective fire extinguishing agents for pool fires are Aqueous Film Forming Foams (AFFF). Today, all available AFFF contain polyfluorinated compounds (PFC), i.e. polyfluorinated tensides (PFT), to establish the aqueous film on the surface of a burning liquid. These fluorinated compounds are persistent, potentially bio-accumulative and toxic. Therefore it is essential to find environmentally sound substitutes for these problematic surfactants. Commercially available fluorine-free foams (FfreeF) lack the ability of aqueous film formation. Although FfreeF are performing well in many situations [1,2], there are numerous scenarios where an aqueous film forming component is mandatory for fast fire extinguishing, e.g. in case of burning liquids. To achieve a well performing AFFF, a new approach is to replace the film forming PFC/PFT by siloxane surfactants. Today, siloxane surfactants are typically used in plant protective agents, in textile surface treatment and as lubricants. As the properties of commercially available siloxane surfactants are not suitable for AFFF, new siloxane surfactants were designed, synthesized and tested for their suitability as film forming ingredients in AFFF formulations. The surface activity and foaming behaviour of model formulations have been determined. Finally, one experimentally fluorine-free AFFF formulation has been subjected to fire tests. In this context a new fire test for scarcely available chemicals is presented.
{"title":"Fire Testing a New Fluorine-free AFFF Based on a Novel Class of Environmentally Sound High Performance Siloxane Surfactants","authors":"Ralf Hetzer, F. Kümmerlen, K. Wirz, D. Blunk","doi":"10.3801/iafss.fss.11-1261","DOIUrl":"https://doi.org/10.3801/iafss.fss.11-1261","url":null,"abstract":"The most effective fire extinguishing agents for pool fires are Aqueous Film Forming Foams (AFFF). Today, all available AFFF contain polyfluorinated compounds (PFC), i.e. polyfluorinated tensides (PFT), to establish the aqueous film on the surface of a burning liquid. These fluorinated compounds are persistent, potentially bio-accumulative and toxic. Therefore it is essential to find environmentally sound substitutes for these problematic surfactants. Commercially available fluorine-free foams (FfreeF) lack the ability of aqueous film formation. Although FfreeF are performing well in many situations [1,2], there are numerous scenarios where an aqueous film forming component is mandatory for fast fire extinguishing, e.g. in case of burning liquids. To achieve a well performing AFFF, a new approach is to replace the film forming PFC/PFT by siloxane surfactants. Today, siloxane surfactants are typically used in plant protective agents, in textile surface treatment and as lubricants. As the properties of commercially available siloxane surfactants are not suitable for AFFF, new siloxane surfactants were designed, synthesized and tested for their suitability as film forming ingredients in AFFF formulations. The surface activity and foaming behaviour of model formulations have been determined. Finally, one experimentally fluorine-free AFFF formulation has been subjected to fire tests. In this context a new fire test for scarcely available chemicals is presented.","PeriodicalId":12145,"journal":{"name":"Fire Safety Science","volume":"29 1","pages":"1261-1270"},"PeriodicalIF":0.0,"publicationDate":"2014-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85277238","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2014-01-01DOI: 10.3801/iafss.fss.11-1247
H. Xue, Y. Li, P. Zhu, W. Qin, Xishi Wang
The effects of obstacles on methane explosion inside a narrow space and its suppression by ultra-fine water mist are investigated experimentally. Two PCB pressure transducers and two E12-1-C-U fast response thermocouples are used to obtain the explosion pressure and temperature, respectively. A Fastcam Ultima APX high speed video camera is used to visualize the process of methane explosion with the influence of obstacles and ultra-fine water mist. The results show that the explosion would be strengthened by the obstacles, while the further strengthening occurs to the cases where the obstacles are farther from the ignition electrode. In addition, the more the obstacles are, the stronger the explosion strengthening will be. The reinforcement effect on gas explosion of the square ring is a little stronger than the column one. The suppression of methane gas explosion containing obstacles with ultra-fine water mist is very effective.
实验研究了障碍物对狭窄空间内甲烷爆炸的影响以及超细水雾对甲烷爆炸的抑制作用。使用两个PCB压力传感器和两个E12-1-C-U快速响应热电偶分别获得爆炸压力和温度。利用Fastcam Ultima APX高速摄像机，对障碍物和超细水雾影响下的甲烷爆炸过程进行了可视化研究。结果表明:障碍物的存在会增强爆炸强度，障碍物离点火电极越远，爆炸强度越强;障碍物越多，爆炸强化效果越强。方圈对瓦斯爆炸的加固作用略强于柱圈。超细水雾对含障碍物的甲烷瓦斯爆炸的抑制效果非常好。
{"title":"Experimental Study on Suppression of Methane Explosion Containing Obstacles with Ultra-fine Water Mist","authors":"H. Xue, Y. Li, P. Zhu, W. Qin, Xishi Wang","doi":"10.3801/iafss.fss.11-1247","DOIUrl":"https://doi.org/10.3801/iafss.fss.11-1247","url":null,"abstract":"The effects of obstacles on methane explosion inside a narrow space and its suppression by ultra-fine water mist are investigated experimentally. Two PCB pressure transducers and two E12-1-C-U fast response thermocouples are used to obtain the explosion pressure and temperature, respectively. A Fastcam Ultima APX high speed video camera is used to visualize the process of methane explosion with the influence of obstacles and ultra-fine water mist. The results show that the explosion would be strengthened by the obstacles, while the further strengthening occurs to the cases where the obstacles are farther from the ignition electrode. In addition, the more the obstacles are, the stronger the explosion strengthening will be. The reinforcement effect on gas explosion of the square ring is a little stronger than the column one. The suppression of methane gas explosion containing obstacles with ultra-fine water mist is very effective.","PeriodicalId":12145,"journal":{"name":"Fire Safety Science","volume":"21 1","pages":"1247-1260"},"PeriodicalIF":0.0,"publicationDate":"2014-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83293383","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2014-01-01DOI: 10.3801/IAFSS.FSS.11-262
B. Dlugogorski, S. Hirunpraditkoon, E. Kennedy
This paper reports the ignition temperature and emissivity of heterogeneous materials characterised by high void fraction of between 0.92 and 0.94 and composed of loose particles of shredded grass and paper, planed wood, shredded plastic bags, as well as sugar and bread, with about 95 % of the particles (by mass) of less than 50 mm in size. These materials reflect a typical composition and void fraction of so-called refusederived fuels (RDF), which are obtained from municipal solid waste, then densified and combusted for energy recovery. An infrared pyrometer, with a spectral response range of 8 to 14 µm, recorded the surface temperature of the surrogate RDF, prior to the onset of the flaming combustion, in a stand alone mass loss calorimeter operated at 20 and 45 kW m -2 . The overlapping spectral ranges of the pyrometer and the radiator heater necessitated the development of a practical methodology to obtain the actual surface temperature from the apparent measurements, which included the effect of the reflected radiation. In addition to surface temperatures (292 ‐ 325 °C for 20 kW m -2 and 250 ‐ 294 °C for 45 kW m -2 ), in this contribution, we estimate the actual emissivities (0.95 ‐ 0.98) of the materials from the intensity of the reflected radiation.
本文报道了一种非均相材料的点火温度和发射率，其特点是孔隙率高，介于0.92和0.94之间，由碎草和纸、刨花、碎塑料袋、糖和面包等松散颗粒组成，其中约95%的颗粒(按质量计)尺寸小于50mm。这些材料反映了所谓的垃圾衍生燃料(RDF)的典型组成和空隙部分，这些燃料是从城市固体废物中获得的，然后致密化和燃烧以回收能量。红外高温计，光谱响应范围为8到14µm，记录了在火焰燃烧开始之前，替代RDF的表面温度，在一个独立的质量损失量热计中工作在20和45 kW m -2。高温计和辐射加热器的光谱范围重叠，需要开发一种实用的方法，从表观测量中获得实际表面温度，其中包括反射辐射的影响。除了表面温度(20 kW m -2时292 ~ 325°C, 45 kW m -2时250 ~ 294°C)外，我们还通过反射辐射强度估算了材料的实际发射率(0.95 ~ 0.98)。
{"title":"Ignition temperature and surface emissivity of heterogeneous loosely packed materials from pyrometric measurements","authors":"B. Dlugogorski, S. Hirunpraditkoon, E. Kennedy","doi":"10.3801/IAFSS.FSS.11-262","DOIUrl":"https://doi.org/10.3801/IAFSS.FSS.11-262","url":null,"abstract":"This paper reports the ignition temperature and emissivity of heterogeneous materials characterised by high void fraction of between 0.92 and 0.94 and composed of loose particles of shredded grass and paper, planed wood, shredded plastic bags, as well as sugar and bread, with about 95 % of the particles (by mass) of less than 50 mm in size. These materials reflect a typical composition and void fraction of so-called refusederived fuels (RDF), which are obtained from municipal solid waste, then densified and combusted for energy recovery. An infrared pyrometer, with a spectral response range of 8 to 14 µm, recorded the surface temperature of the surrogate RDF, prior to the onset of the flaming combustion, in a stand alone mass loss calorimeter operated at 20 and 45 kW m -2 . The overlapping spectral ranges of the pyrometer and the radiator heater necessitated the development of a practical methodology to obtain the actual surface temperature from the apparent measurements, which included the effect of the reflected radiation. In addition to surface temperatures (292 ‐ 325 °C for 20 kW m -2 and 250 ‐ 294 °C for 45 kW m -2 ), in this contribution, we estimate the actual emissivities (0.95 ‐ 0.98) of the materials from the intensity of the reflected radiation.","PeriodicalId":12145,"journal":{"name":"Fire Safety Science","volume":"66 1","pages":"262-275"},"PeriodicalIF":0.0,"publicationDate":"2014-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87755749","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2014-01-01DOI: 10.3801/iafss.fss.11-419
W. Shi, J. Ji, Jinhua Sun, S. Lo, Linjie Li, X. Yuan
A set of experiments were conducted in a scaled building model with 12 floors to study on the temperatures of fire room under stack effect in a high-rise building. The fuel mass loss rate, radiant flux, heat flux and temperatures in the atria and fire room at the first floor were experimentally investigated. The flames of pool fires in room are tilted towards the staircase under the air flow induced by the stack effect. The mass loss rate of fuel is influenced slightly by the position of window opened in the staircase, while the temperature distribution in the atria and fire room is different in the opened and closed staircases. The hot smoke temperatures in the atria and fire room at the first floor increase with an increasing pool size. The upper hot smoke temperatures in the atria are higher than those in the fire room in cases with an opened staircase. Compared different positions of the window opened in the staircase, it can be found that the upper hot smoke temperatures in the atria in cases with the 3 rd floor window opened are the highest due to the weaker stack effect. In the closed staircases, the upper hot smoke temperatures in the fire room are great higher than these in the atria at the first floor. Besides, the radiant flux and heat flux of the left sidewalls of staircase in an opened staircase are higher than those in a closed staircase, due to the tilted flame. The results obtained in this paper may be used for the safety design of the room in high-rise buildings.
{"title":"Experimental Study on the Characteristics of Temperature Field of Fire Room under Stack Effect in a Scaled High-rise Building Model","authors":"W. Shi, J. Ji, Jinhua Sun, S. Lo, Linjie Li, X. Yuan","doi":"10.3801/iafss.fss.11-419","DOIUrl":"https://doi.org/10.3801/iafss.fss.11-419","url":null,"abstract":"A set of experiments were conducted in a scaled building model with 12 floors to study on the temperatures of fire room under stack effect in a high-rise building. The fuel mass loss rate, radiant flux, heat flux and temperatures in the atria and fire room at the first floor were experimentally investigated. The flames of pool fires in room are tilted towards the staircase under the air flow induced by the stack effect. The mass loss rate of fuel is influenced slightly by the position of window opened in the staircase, while the temperature distribution in the atria and fire room is different in the opened and closed staircases. The hot smoke temperatures in the atria and fire room at the first floor increase with an increasing pool size. The upper hot smoke temperatures in the atria are higher than those in the fire room in cases with an opened staircase. Compared different positions of the window opened in the staircase, it can be found that the upper hot smoke temperatures in the atria in cases with the 3 rd floor window opened are the highest due to the weaker stack effect. In the closed staircases, the upper hot smoke temperatures in the fire room are great higher than these in the atria at the first floor. Besides, the radiant flux and heat flux of the left sidewalls of staircase in an opened staircase are higher than those in a closed staircase, due to the tilted flame. The results obtained in this paper may be used for the safety design of the room in high-rise buildings.","PeriodicalId":12145,"journal":{"name":"Fire Safety Science","volume":"66 1","pages":"419-431"},"PeriodicalIF":0.0,"publicationDate":"2014-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83810245","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2014-01-01DOI: 10.3801/iafss.fss.11-969
K. Frank, M. Spearpoint, S. Weddell
Data for the probability that a doors are open or closed in the event of a fire is sparse. The literature only presents a snap-shot rather than how the position of the door has changed over time. This paper describes the development of a low-cost, unobtrusive logging device that can continuously monitor the position of a door for extended periods. The devices were used to record 180 days of data from 52 doors located in different types of sleeping occupancies: hotels, apartments, dormitories and rest homes. Results were obtained for the probability that doors were open during day-time and night-time; and also during weekdays and weekends. Overall a probability distribution for the fraction of time that a door was found to be open is an inverse Gaussian function with mean µ = 0.104 and shape factor l = 0.0117.
{"title":"Finding the Probability of Doors Being Open Using a Continuous Position Logger","authors":"K. Frank, M. Spearpoint, S. Weddell","doi":"10.3801/iafss.fss.11-969","DOIUrl":"https://doi.org/10.3801/iafss.fss.11-969","url":null,"abstract":"Data for the probability that a doors are open or closed in the event of a fire is sparse. The literature only presents a snap-shot rather than how the position of the door has changed over time. This paper describes the development of a low-cost, unobtrusive logging device that can continuously monitor the position of a door for extended periods. The devices were used to record 180 days of data from 52 doors located in different types of sleeping occupancies: hotels, apartments, dormitories and rest homes. Results were obtained for the probability that doors were open during day-time and night-time; and also during weekdays and weekends. Overall a probability distribution for the fraction of time that a door was found to be open is an inverse Gaussian function with mean µ = 0.104 and shape factor l = 0.0117.","PeriodicalId":12145,"journal":{"name":"Fire Safety Science","volume":"37 1","pages":"969-982"},"PeriodicalIF":0.0,"publicationDate":"2014-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89200683","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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