Pub Date : 2014-01-01DOI: 10.3801/iafss.fss.11-138
Damien Marquis, É. Guillaume, A. Camillo
The reaction-to-fire of materials is commonly studied with bench scale experiments conducted under controlled test conditions. Two bench-scale instruments commonly used for this purpose are the cone calorimeter and the fire propagation apparatus. Research performed with these test apparatuses on the burning behaviour of polymeric materials has demonstrated the significant effect on the results of test variables such as pressure, irradiance, flow velocity, etc. In spite of the fairly large number of studies, little is known concerning the effect of oxygen vitiation and reduced ventilation on the burning behaviour of polymeric materials. Recent work in a controlled oxygen environment raises the question of interpretation and accuracy of the results. This paper reports the results of a study to evaluate the effect of oxygen vitiation and reduced ventilation on the burning behaviour of materials in a controlled atmosphere cone calorimeter. The study was performed on a typical thermoplastic material, i.e., a black poly(methyl)methacrylate. The dependence of the results on the experimental fire conditions is presented and discussed. The experiments show that the inlet airflow rate is a major factor to consider when studying the burning behaviour of polymeric materials in an enclosure. It strongly affects the available amount of oxygen that can react and may lead to a misinterpretation of the results when the effects of oxygen are studied.
{"title":"Effects of oxygen availability on the combustion behaviour of materials in a controlled atmosphere cone calorimeter","authors":"Damien Marquis, É. Guillaume, A. Camillo","doi":"10.3801/iafss.fss.11-138","DOIUrl":"https://doi.org/10.3801/iafss.fss.11-138","url":null,"abstract":"The reaction-to-fire of materials is commonly studied with bench scale experiments conducted under controlled test conditions. Two bench-scale instruments commonly used for this purpose are the cone calorimeter and the fire propagation apparatus. Research performed with these test apparatuses on the burning behaviour of polymeric materials has demonstrated the significant effect on the results of test variables such as pressure, irradiance, flow velocity, etc. In spite of the fairly large number of studies, little is known concerning the effect of oxygen vitiation and reduced ventilation on the burning behaviour of polymeric materials. Recent work in a controlled oxygen environment raises the question of interpretation and accuracy of the results. This paper reports the results of a study to evaluate the effect of oxygen vitiation and reduced ventilation on the burning behaviour of materials in a controlled atmosphere cone calorimeter. The study was performed on a typical thermoplastic material, i.e., a black poly(methyl)methacrylate. The dependence of the results on the experimental fire conditions is presented and discussed. The experiments show that the inlet airflow rate is a major factor to consider when studying the burning behaviour of polymeric materials in an enclosure. It strongly affects the available amount of oxygen that can react and may lead to a misinterpretation of the results when the effects of oxygen are studied.","PeriodicalId":12145,"journal":{"name":"Fire Safety Science","volume":"134 1","pages":"138-151"},"PeriodicalIF":0.0,"publicationDate":"2014-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73742538","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.11-1196
K. Usui, K. Matsuyama
Suppression system by water spray such as sprinkler system is installed in many buildings and well-known as one of highly effective fire protection methods for enclosure. On the other hand, sprinkler system (hereinafter referred to as SP) would have other effects, such as cooling effect in a compartment, cooling effect of building structure and attenuation of radiant heat flux from fire. In this paper, attenuation of radiant heat flux through water droplets were investigated by full-scale experiments. The fuels were used nheptane and ethanol for comparison of influence of soot particle. 5 kinds of sprinkler nozzles were used in the experiment. Firstly, the fundamental data of the nozzles and flame such as droplets diameter, droplets velocity and distribution of water droplets and radiant spectrum of flame were investigated. Moreover, absorption and transmittance of radiant heat flux was calculated by the Mie theory. And also, an improved prediction model on radiant spectrum was used to predict the radiant spectrum of flame. Thus, absorption and transmittance of radiant heat flux can be calculated by above flame data and fundamental SP data. As the result of calculation parametrically, radiant heat attenuation increases with decreases of droplets diameter. And, it increase approximately linearly depends on amount of total droplets.
{"title":"An Experimental Study on Attenuation of Radiant Heat Flux from Flame through Water Droplets","authors":"K. Usui, K. Matsuyama","doi":"10.3801/iafss.fss.11-1196","DOIUrl":"https://doi.org/10.3801/iafss.fss.11-1196","url":null,"abstract":"Suppression system by water spray such as sprinkler system is installed in many buildings and well-known as one of highly effective fire protection methods for enclosure. On the other hand, sprinkler system (hereinafter referred to as SP) would have other effects, such as cooling effect in a compartment, cooling effect of building structure and attenuation of radiant heat flux from fire. In this paper, attenuation of radiant heat flux through water droplets were investigated by full-scale experiments. The fuels were used nheptane and ethanol for comparison of influence of soot particle. 5 kinds of sprinkler nozzles were used in the experiment. Firstly, the fundamental data of the nozzles and flame such as droplets diameter, droplets velocity and distribution of water droplets and radiant spectrum of flame were investigated. Moreover, absorption and transmittance of radiant heat flux was calculated by the Mie theory. And also, an improved prediction model on radiant spectrum was used to predict the radiant spectrum of flame. Thus, absorption and transmittance of radiant heat flux can be calculated by above flame data and fundamental SP data. As the result of calculation parametrically, radiant heat attenuation increases with decreases of droplets diameter. And, it increase approximately linearly depends on amount of total droplets.","PeriodicalId":12145,"journal":{"name":"Fire Safety Science","volume":"7 1","pages":"1196-1207"},"PeriodicalIF":0.0,"publicationDate":"2014-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74071292","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.11-444
D. Wong, K. Li, M. Spearpoint
This paper investigates the area of window fallout behaviour of 4 mm and 6 mm thick single glazed ordinary float type glass exposed to a constant radiant heat. Regular rubber beadings and non-standard ceramic fibre beadings were used to mount the 525 mm square glass samples in commercial aluminium window frames. A total of 117 experiments were carried out where the area of glass fallout was recorded as a function of time. The average heat fluxes which the glass samples were exposed to ranged from 13 kW/m 2 to 58 kW/m 2 . The lowest heat flux that is needed for fallout occurrence is found to be 20 kW/m 2 for 4 mm thick glass and 28 kW/m 2 for 6 mm thick glass. The fallout behaviour of glass was quantified with an exponential distribution function and a probabilistic area of glass fallout prediction model for 4 mm and 6 mm thick glass is developed from the experimental results.
{"title":"A Probabilistic Model for the Fallout Area of Single Glazing under Radiant Heat Exposure","authors":"D. Wong, K. Li, M. Spearpoint","doi":"10.3801/iafss.fss.11-444","DOIUrl":"https://doi.org/10.3801/iafss.fss.11-444","url":null,"abstract":"This paper investigates the area of window fallout behaviour of 4 mm and 6 mm thick single glazed ordinary float type glass exposed to a constant radiant heat. Regular rubber beadings and non-standard ceramic fibre beadings were used to mount the 525 mm square glass samples in commercial aluminium window frames. A total of 117 experiments were carried out where the area of glass fallout was recorded as a function of time. The average heat fluxes which the glass samples were exposed to ranged from 13 kW/m 2 to 58 kW/m 2 . The lowest heat flux that is needed for fallout occurrence is found to be 20 kW/m 2 for 4 mm thick glass and 28 kW/m 2 for 6 mm thick glass. The fallout behaviour of glass was quantified with an exponential distribution function and a probabilistic area of glass fallout prediction model for 4 mm and 6 mm thick glass is developed from the experimental results.","PeriodicalId":12145,"journal":{"name":"Fire Safety Science","volume":"78 1","pages":"444-457"},"PeriodicalIF":0.0,"publicationDate":"2014-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83889241","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.11-1420
K. Zhou, Naian Liu, Panpan Yin, Xieshang Yuan, Juncheng Jiang, S. Key
During the wildland fire of Brazil in 2010 (http://www.dailymail.co.uk/sciencetech/article-1306088/Braziltornado-Whirling-column-flames-sweeps-burning-fields.html), a special fire whirl occurred over a narrow but long fire front and moved due to the wind effect. This paper presents an elementary study on such a moving fire whirl by conducting line fire experiments with cross wind. Experimental analysis indicates that a line fire near the ground, a reasonable attack angle between the line fire and the cross wind, and wind speed within a critical range are the three essential conditions for the formation of fire whirl in a line fire. By examining the advection and bending of vorticity, it is also deduced that the concentrated vortex of fire whirl results from the coupling of the line fire plume and the horizontal vortex line near the ground surface. By assuming the solid-body rotation of fire whirl flame, a possible mechanism of moving fire whirl is proposed, which states that the flame moving is mainly controlled by the drag force, lift force and ground friction. Accurate experimental measurements are needed to testify or verify this mechanism in the future work.
{"title":"Fire Whirl due to Interaction between Line Fire and Cross Wind","authors":"K. Zhou, Naian Liu, Panpan Yin, Xieshang Yuan, Juncheng Jiang, S. Key","doi":"10.3801/iafss.fss.11-1420","DOIUrl":"https://doi.org/10.3801/iafss.fss.11-1420","url":null,"abstract":"During the wildland fire of Brazil in 2010 (http://www.dailymail.co.uk/sciencetech/article-1306088/Braziltornado-Whirling-column-flames-sweeps-burning-fields.html), a special fire whirl occurred over a narrow but long fire front and moved due to the wind effect. This paper presents an elementary study on such a moving fire whirl by conducting line fire experiments with cross wind. Experimental analysis indicates that a line fire near the ground, a reasonable attack angle between the line fire and the cross wind, and wind speed within a critical range are the three essential conditions for the formation of fire whirl in a line fire. By examining the advection and bending of vorticity, it is also deduced that the concentrated vortex of fire whirl results from the coupling of the line fire plume and the horizontal vortex line near the ground surface. By assuming the solid-body rotation of fire whirl flame, a possible mechanism of moving fire whirl is proposed, which states that the flame moving is mainly controlled by the drag force, lift force and ground friction. Accurate experimental measurements are needed to testify or verify this mechanism in the future work.","PeriodicalId":12145,"journal":{"name":"Fire Safety Science","volume":"37 1","pages":"1420-1429"},"PeriodicalIF":0.0,"publicationDate":"2014-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80949453","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.11-1077
Q. Xie, Shouxiang Lu, D. Cóstola, J. Hensen
In performance-based design of buildings, much attention is paid to design parameters by fire engineers or experts. However, due to the time-consuming evacuation models, it is computationally prohibitive to adopt the conventional Monte Carlo simulation (MCS) to examine the effects of design parameters on evacuation time under uncertainty. To determine suitable design parameters under uncertainty with the reduced significantly computational cost, an arbitrary polynomial chaos-based method is presented in this paper. Arbitrary polynomial chaos expansion is used to construct surrogate models of evacuation time based on complex evacuation models. Afterwards, simple analytical method can be adapted to calculate the mean, standard deviation of evacuation time and Sobol sensitivity indices based on the arbitrary polynomial chaos coefficients. Moreover, the distribution of evacuation time can be generated by combining Latin hypercube sampling (LHS) with the obtained surrogate model. To demonstrate the proposed method, a hypothetical single-storey fire compartment with two exits is presented as a case in accordance with the Chinese code GB50016-2012, evaluating the impact of exit width on evacuation time under uncertain occupant density and child-occupant load ratio. And results show that the proposed method can achieve the distribution of evacuation time close to that from the MCS while dramatically reducing the number of evacuation simulations. When exit width per 100 persons is designed between 0.1 m and 0.5 m, the uncertainty of evacuation time is severely affected by exit width, which is more significant in smaller exit width. However, exit width has a small effect on Sobol sensitivity indices, the reliability level of a certain safety factor, and safety factor at a certain reliability level.
{"title":"An Arbitrary Polynomial Chaos-Based Approach to Analyzing the Impacts of Design Parameters on Evacuation Time under Uncertainty","authors":"Q. Xie, Shouxiang Lu, D. Cóstola, J. Hensen","doi":"10.3801/iafss.fss.11-1077","DOIUrl":"https://doi.org/10.3801/iafss.fss.11-1077","url":null,"abstract":"In performance-based design of buildings, much attention is paid to design parameters by fire engineers or experts. However, due to the time-consuming evacuation models, it is computationally prohibitive to adopt the conventional Monte Carlo simulation (MCS) to examine the effects of design parameters on evacuation time under uncertainty. To determine suitable design parameters under uncertainty with the reduced significantly computational cost, an arbitrary polynomial chaos-based method is presented in this paper. Arbitrary polynomial chaos expansion is used to construct surrogate models of evacuation time based on complex evacuation models. Afterwards, simple analytical method can be adapted to calculate the mean, standard deviation of evacuation time and Sobol sensitivity indices based on the arbitrary polynomial chaos coefficients. Moreover, the distribution of evacuation time can be generated by combining Latin hypercube sampling (LHS) with the obtained surrogate model. To demonstrate the proposed method, a hypothetical single-storey fire compartment with two exits is presented as a case in accordance with the Chinese code GB50016-2012, evaluating the impact of exit width on evacuation time under uncertain occupant density and child-occupant load ratio. And results show that the proposed method can achieve the distribution of evacuation time close to that from the MCS while dramatically reducing the number of evacuation simulations. When exit width per 100 persons is designed between 0.1 m and 0.5 m, the uncertainty of evacuation time is severely affected by exit width, which is more significant in smaller exit width. However, exit width has a small effect on Sobol sensitivity indices, the reliability level of a certain safety factor, and safety factor at a certain reliability level.","PeriodicalId":12145,"journal":{"name":"Fire Safety Science","volume":"28 1","pages":"1077-1090"},"PeriodicalIF":0.0,"publicationDate":"2014-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82373806","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.11-691
A. Sekizawa, K. Sasaki
The 2011 Great East-Japan Earthquake of March 11, 2011, caused large-scale fire damage across a wide area, with the type and extent of fire damage exceeding that caused by the 1995 Kobe Earthquake. A particularly distinctive characteristic was the many fires caused either directly or indirectly by the tsunami. The mechanism of occurrence and development of tsunami-induced fires differs significantly from typical earthquake-induced fires. Given these two very different types of initiation scenarios, fires following the Great East-Japan Earthquake were analyzed based on factors such as regional distribution, causes of ignition, pattern of fire development and spread, and size of fire. Data for these analyses were collected from questionnaire surveys of fire departments located in the affected areas. In addition, data are presented on the relationship between seismic intensity and the incidence of earthquake-induced fires. A significant finding from the analysis is that, given the impacts to infrastructure and extent of damage, tsunami-induced fires are likely to spread beyond the control of fire brigades. Therefore, the prevention and mitigation of tsunami-induced fires in the future earthquakes is of great significance.
{"title":"Study on Fires Following the 2011 Great East-Japan Earthquake based on the Questionnaire Survey to Fire Departments in Affected Areas","authors":"A. Sekizawa, K. Sasaki","doi":"10.3801/iafss.fss.11-691","DOIUrl":"https://doi.org/10.3801/iafss.fss.11-691","url":null,"abstract":"The 2011 Great East-Japan Earthquake of March 11, 2011, caused large-scale fire damage across a wide area, with the type and extent of fire damage exceeding that caused by the 1995 Kobe Earthquake. A particularly distinctive characteristic was the many fires caused either directly or indirectly by the tsunami. The mechanism of occurrence and development of tsunami-induced fires differs significantly from typical earthquake-induced fires. Given these two very different types of initiation scenarios, fires following the Great East-Japan Earthquake were analyzed based on factors such as regional distribution, causes of ignition, pattern of fire development and spread, and size of fire. Data for these analyses were collected from questionnaire surveys of fire departments located in the affected areas. In addition, data are presented on the relationship between seismic intensity and the incidence of earthquake-induced fires. A significant finding from the analysis is that, given the impacts to infrastructure and extent of damage, tsunami-induced fires are likely to spread beyond the control of fire brigades. Therefore, the prevention and mitigation of tsunami-induced fires in the future earthquakes is of great significance.","PeriodicalId":12145,"journal":{"name":"Fire Safety Science","volume":"334 1","pages":"691-703"},"PeriodicalIF":0.0,"publicationDate":"2014-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83451398","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.11-769
B. Kandola, L. Krishnan
This work explores the possibility of reducing the flammability of unsaturated polyester (UP) resin, commonly used in marine composites, by co-blending with less combustible and char-forming resins such as phenol-formaldehyde, melamine-formaldehyde and furans. The compatibility and curing properties of UP, other resins and their blends in 50:50 wt-% ratios have been have been studied by differential scanning calorimetry (DSC) and dynamic mechanical thermal analysis (DMTA) techniques. Based on the successful establishment of curing conditions, plaques of resins have been cast and cured. Thermal stability has been studied by thermogravimetry (TGA), whereas the fire performance evaluation was carried out by limiting oxygen index (LOI) and cone calorimtery at 50kW/m 2 heat flux. According to a fire risk assessment based on cone calorimetric data, the resole phenolic resins and their blends with UP achieved the highest fire safety rating.
{"title":"Fire performance evaluation of different resins for potential application in fire resistant structural marine composites","authors":"B. Kandola, L. Krishnan","doi":"10.3801/IAFSS.FSS.11-769","DOIUrl":"https://doi.org/10.3801/IAFSS.FSS.11-769","url":null,"abstract":"This work explores the possibility of reducing the flammability of unsaturated polyester (UP) resin, commonly used in marine composites, by co-blending with less combustible and char-forming resins such as phenol-formaldehyde, melamine-formaldehyde and furans. The compatibility and curing properties of UP, other resins and their blends in 50:50 wt-% ratios have been have been studied by differential scanning calorimetry (DSC) and dynamic mechanical thermal analysis (DMTA) techniques. Based on the successful establishment of curing conditions, plaques of resins have been cast and cured. Thermal stability has been studied by thermogravimetry (TGA), whereas the fire performance evaluation was carried out by limiting oxygen index (LOI) and cone calorimtery at 50kW/m 2 heat flux. According to a fire risk assessment based on cone calorimetric data, the resole phenolic resins and their blends with UP achieved the highest fire safety rating.","PeriodicalId":12145,"journal":{"name":"Fire Safety Science","volume":"111 1","pages":"769-780"},"PeriodicalIF":0.0,"publicationDate":"2014-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89371047","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.11-1298
W. Chow, X. Ni
Experiments with burning cooking oil in open kitchen fires are reported in this paper. Heat release rate, flame temperature, burning duration and heat fluxes of cooking oil fires were measured. Performances of water mist and gas-solid composite dry powders in suppressing cooking oil fires were evaluated by experiments. Reduction in gas temperature distributions, changes in heat fluxes and suppression time were then measured. Experimental data will provide necessary information for hazard assessment of open kitchen in the residential units of tall buildings.
{"title":"Experimental Evaluation on Performance of Open Kitchen Fire Suppression Systems","authors":"W. Chow, X. Ni","doi":"10.3801/iafss.fss.11-1298","DOIUrl":"https://doi.org/10.3801/iafss.fss.11-1298","url":null,"abstract":"Experiments with burning cooking oil in open kitchen fires are reported in this paper. Heat release rate, flame temperature, burning duration and heat fluxes of cooking oil fires were measured. Performances of water mist and gas-solid composite dry powders in suppressing cooking oil fires were evaluated by experiments. Reduction in gas temperature distributions, changes in heat fluxes and suppression time were then measured. Experimental data will provide necessary information for hazard assessment of open kitchen in the residential units of tall buildings.","PeriodicalId":12145,"journal":{"name":"Fire Safety Science","volume":"75 1","pages":"1298-1311"},"PeriodicalIF":0.0,"publicationDate":"2014-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75382461","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.11-1103
X. Wei, X. Mai, W. Lv, W. Song
The research of human crowd dynamic is significant for the building designers and emergency guiders. However, current researches mainly focus on the interactions among isolated individuals, the influence of social interactions among pedestrian is needed to take into consideration in the pedestrian dynamic study. In this manuscript we carried out observed experiments of the movement of pedestrian group and used optical flow algorithm to extract pedestrian’s trajectory from the video. Then the movement characteristics of the group members were analyzed and discussed, which include the angle, the distance, the velocity, the group alignment, step frequency and the offset angle of group member. It indicates group members have adaptive ability to maintain the group structure and the velocity fluctuation of the group is small. It is found that the velocity and step frequency of group member are smaller than that of individuals under the same scenario. Movement consistency of the group members is also verified. These experimental results will be a support for modeling pedestrian group.
{"title":"Microscopic Character and Movement Consistency of Pedestrian Group: An Experimental Study in Campus","authors":"X. Wei, X. Mai, W. Lv, W. Song","doi":"10.3801/iafss.fss.11-1103","DOIUrl":"https://doi.org/10.3801/iafss.fss.11-1103","url":null,"abstract":"The research of human crowd dynamic is significant for the building designers and emergency guiders. However, current researches mainly focus on the interactions among isolated individuals, the influence of social interactions among pedestrian is needed to take into consideration in the pedestrian dynamic study. In this manuscript we carried out observed experiments of the movement of pedestrian group and used optical flow algorithm to extract pedestrian’s trajectory from the video. Then the movement characteristics of the group members were analyzed and discussed, which include the angle, the distance, the velocity, the group alignment, step frequency and the offset angle of group member. It indicates group members have adaptive ability to maintain the group structure and the velocity fluctuation of the group is small. It is found that the velocity and step frequency of group member are smaller than that of individuals under the same scenario. Movement consistency of the group members is also verified. These experimental results will be a support for modeling pedestrian group.","PeriodicalId":12145,"journal":{"name":"Fire Safety Science","volume":"39 1","pages":"1103-1114"},"PeriodicalIF":0.0,"publicationDate":"2014-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74335936","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.11-1271
V. Novozhilov
Lagrangian model of droplet movement in axisymmetrical fluid flow is considered in application to water sprays in active fire control systems, such as sprinklers, aerosols and water mists. In contrast to previously known models equations of droplet motion are integrated in much more general form, with axial flow velocity being arbitrary function of two spatial coordinates. Second major advantage of the model is that it fully accounts for the droplet evaporation. Explicit formulas are derived for vaporization rate density and drag force at any location in the flow. Such formulas are directly applicable in a number of fire engineering problems, for example in estimating compartment cooling rates by water sprays, and in studying smoke layer destabilization by sprinkler or water mist sprays.
{"title":"Water Spray Dynamics in Fire Flows","authors":"V. Novozhilov","doi":"10.3801/IAFSS.FSS.11-1271","DOIUrl":"https://doi.org/10.3801/IAFSS.FSS.11-1271","url":null,"abstract":"Lagrangian model of droplet movement in axisymmetrical fluid flow is considered in application to water sprays in active fire control systems, such as sprinklers, aerosols and water mists. In contrast to previously known models equations of droplet motion are integrated in much more general form, with axial flow velocity being arbitrary function of two spatial coordinates. Second major advantage of the model is that it fully accounts for the droplet evaporation. Explicit formulas are derived for vaporization rate density and drag force at any location in the flow. Such formulas are directly applicable in a number of fire engineering problems, for example in estimating compartment cooling rates by water sprays, and in studying smoke layer destabilization by sprinkler or water mist sprays.","PeriodicalId":12145,"journal":{"name":"Fire Safety Science","volume":"1 1","pages":"1271-1284"},"PeriodicalIF":0.0,"publicationDate":"2014-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74101766","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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