Pub Date : 2011-02-01DOI: 10.1177/1042391510394496
R. Ashcraft, Alfonso F. Ibarreta, Timothy J. Myers
The potential dangers associated with exposed fuel gas pipes in areas of significant snowfall are examined. There have been numerous incidents in the past two decades where snow loading or impact on fuel gas equipment has been identified as one step in the sequence of events leading to fires or explosions. This study experimentally and numerically examines the possibility of snow cover creating a preferential pathway for gas flow into a nearby structure from a leaking pipe. Simple experiments show that when a suspended pipe is covered with snow, a gap often forms directly underneath the pipe, which has the potential to serve as a low-resistance flow path for fugitive fuel gas. Using a simplified geometry, the fraction of gas entering a nearby structure from a leaking, snow-covered pipe is examined using finite differences to solve the flow equations in porous media. The snow cover is shown to force a large portion of the fugitive gas toward the structure under certain circumstances and has the potential to create additional hazards that would not be present without the snow layer. Using sensitivity analysis, the major parameters governing fugitive gas flow are determined, which include internal structure pressure, gap size, snow permeability, and distance of the leak from the structure.
{"title":"Leaking gas from a snow-covered pipe: empirical evidence and modeling of preferential flow paths","authors":"R. Ashcraft, Alfonso F. Ibarreta, Timothy J. Myers","doi":"10.1177/1042391510394496","DOIUrl":"https://doi.org/10.1177/1042391510394496","url":null,"abstract":"The potential dangers associated with exposed fuel gas pipes in areas of significant snowfall are examined. There have been numerous incidents in the past two decades where snow loading or impact on fuel gas equipment has been identified as one step in the sequence of events leading to fires or explosions. This study experimentally and numerically examines the possibility of snow cover creating a preferential pathway for gas flow into a nearby structure from a leaking pipe. Simple experiments show that when a suspended pipe is covered with snow, a gap often forms directly underneath the pipe, which has the potential to serve as a low-resistance flow path for fugitive fuel gas. Using a simplified geometry, the fraction of gas entering a nearby structure from a leaking, snow-covered pipe is examined using finite differences to solve the flow equations in porous media. The snow cover is shown to force a large portion of the fugitive gas toward the structure under certain circumstances and has the potential to create additional hazards that would not be present without the snow layer. Using sensitivity analysis, the major parameters governing fugitive gas flow are determined, which include internal structure pressure, gap size, snow permeability, and distance of the leak from the structure.","PeriodicalId":50192,"journal":{"name":"Journal of Fire Protection Engineering","volume":"21 1","pages":"57-79"},"PeriodicalIF":0.0,"publicationDate":"2011-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1177/1042391510394496","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"65326792","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 : 2011-01-19DOI: 10.1177/1042391510394242
H. Ingason, Ying Zhen Li
Experimental results are presented from a series of tests in a model scale tunnel (1 : 23). This study focuses on single and two-point extraction ventilation systems to complement a previous study with the same apparatus using longitudinal ventilation only. The point extraction ventilation system in this test series was operated under different fire loads and flow conditions of either forced longitudinal ventilation or natural ventilation. Wood crib piles were used to simulate the fire source, which was designed to correspond to a ‘heavy goods vehicle’ fire load at full scale. The parameters varied were the number of wood cribs, the longitudinal ventilation velocity, and the arrangement of the extraction vent openings and their exhaust capacity. Measurement data were obtained for maximum heat release rates, fire growth rates, maximum excess temperatures beneath the ceiling, and heat fluxes. Fire spread between wood cribs with a separation distance corresponding to 15 m at full scale was also investigated. These data are reproduced well by empirical correlations that were established as part of the study. It is concluded that fire and smoke flows upstream and downstream of the fire source can be fully controlled if the ventilation velocities upstream and downstream are above about 2.9 and 3.8 m/s, respectively, at full scale for a single-point extraction ventilation system and greater than about 2.9 m/s on both sides at full scale for a two-point system.
{"title":"Model scale tunnel fire tests with point extraction ventilation","authors":"H. Ingason, Ying Zhen Li","doi":"10.1177/1042391510394242","DOIUrl":"https://doi.org/10.1177/1042391510394242","url":null,"abstract":"Experimental results are presented from a series of tests in a model scale tunnel (1 : 23). This study focuses on single and two-point extraction ventilation systems to complement a previous study with the same apparatus using longitudinal ventilation only. The point extraction ventilation system in this test series was operated under different fire loads and flow conditions of either forced longitudinal ventilation or natural ventilation. Wood crib piles were used to simulate the fire source, which was designed to correspond to a ‘heavy goods vehicle’ fire load at full scale. The parameters varied were the number of wood cribs, the longitudinal ventilation velocity, and the arrangement of the extraction vent openings and their exhaust capacity. Measurement data were obtained for maximum heat release rates, fire growth rates, maximum excess temperatures beneath the ceiling, and heat fluxes. Fire spread between wood cribs with a separation distance corresponding to 15 m at full scale was also investigated. These data are reproduced well by empirical correlations that were established as part of the study. It is concluded that fire and smoke flows upstream and downstream of the fire source can be fully controlled if the ventilation velocities upstream and downstream are above about 2.9 and 3.8 m/s, respectively, at full scale for a single-point extraction ventilation system and greater than about 2.9 m/s on both sides at full scale for a two-point system.","PeriodicalId":50192,"journal":{"name":"Journal of Fire Protection Engineering","volume":"21 1","pages":"5-36"},"PeriodicalIF":0.0,"publicationDate":"2011-01-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1177/1042391510394242","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"65326524","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 : 2011-01-19DOI: 10.1177/1042391510394244
N. Braxtan, S. Pessiki
Sprayed fire resistive material (SFRM) is intended to thermally protect structural steel elements during a fire. The integrity of the SFRM may become compromised during an earthquake due to yielding and damage in the underlying steel structure to which the SFRM is bonded. This in turn can influence the post-earthquake fire performance of the SFRM. Tests were performed to evaluate the bond performance of SFRM on steel plates subjected to tensile yielding. The test results show rapid degradation of the bond strength of SFRM to steel plates with increasing tensile yielding. Test results also show marked differences in bond behavior between wet mix and dry mix SFRM and between coatings on steel with a mill finish as opposed to a sand blasted finish.
{"title":"Bond performance of SFRM on steel plates subjected to tensile yielding","authors":"N. Braxtan, S. Pessiki","doi":"10.1177/1042391510394244","DOIUrl":"https://doi.org/10.1177/1042391510394244","url":null,"abstract":"Sprayed fire resistive material (SFRM) is intended to thermally protect structural steel elements during a fire. The integrity of the SFRM may become compromised during an earthquake due to yielding and damage in the underlying steel structure to which the SFRM is bonded. This in turn can influence the post-earthquake fire performance of the SFRM. Tests were performed to evaluate the bond performance of SFRM on steel plates subjected to tensile yielding. The test results show rapid degradation of the bond strength of SFRM to steel plates with increasing tensile yielding. Test results also show marked differences in bond behavior between wet mix and dry mix SFRM and between coatings on steel with a mill finish as opposed to a sand blasted finish.","PeriodicalId":50192,"journal":{"name":"Journal of Fire Protection Engineering","volume":"249 1","pages":"37-55"},"PeriodicalIF":0.0,"publicationDate":"2011-01-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1177/1042391510394244","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"65326283","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 : 2010-11-01DOI: 10.1177/1042391510367366
A. Sharifian, D. Buttsworth
A computational technique is used to establish a view factor correlation for the target-object — screen — bushfire arrangement for aligned, double-layered screens consisting of woven wire, square-celled elements. The results indicate that the average view factor between an infinite fire and a target object of the same size as the square cell is related to the porosity of screens. The spacing of two layers only affects the view factor if two screen layers are very close. The results also show that it is possible to block up to about 98% of the direct radiant heat flux by using a low porosity (25%) double-layered screen.
{"title":"Double-layered metal mesh screens to contain or exclude thermal radiation from bush fires","authors":"A. Sharifian, D. Buttsworth","doi":"10.1177/1042391510367366","DOIUrl":"https://doi.org/10.1177/1042391510367366","url":null,"abstract":"A computational technique is used to establish a view factor correlation for the target-object — screen — bushfire arrangement for aligned, double-layered screens consisting of woven wire, square-celled elements. The results indicate that the average view factor between an infinite fire and a target object of the same size as the square cell is related to the porosity of screens. The spacing of two layers only affects the view factor if two screen layers are very close. The results also show that it is possible to block up to about 98% of the direct radiant heat flux by using a low porosity (25%) double-layered screen.","PeriodicalId":50192,"journal":{"name":"Journal of Fire Protection Engineering","volume":"20 1","pages":"291-311"},"PeriodicalIF":0.0,"publicationDate":"2010-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1177/1042391510367366","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"65325919","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 : 2010-11-01DOI: 10.1177/1042391510379807
R. Harrison, M. Spearpoint
All existing simple entrainment calculation methods for the three-dimensional (3D) balcony spill plume assume that the mass flow rate of gases produced increases linearly with height of rise. It is recognized that at very large heights of rise the balcony spill plume will eventually behave like an axisymmetric plume in terms of entrainment behavior. The transition from a balcony spill plume to axisymmetric has not been rigorously studied and current guidance can only be considered to be an estimate. To remedy this situation, a general approach similar to that used in previous work is utilized to develop a simple approximation that predicts the height of transition in entrainment behavior. This type of analysis is further supported with a limited number of simulations using numerical modeling. The proposed simple approximation provides an upper height limit for which linearly based 3D balcony spill plume entrainment formulae can successfully be applied.
{"title":"A Simple Approximation to Predict the Transition from a Balcony Spill Plume to an Axisymmetric Plume","authors":"R. Harrison, M. Spearpoint","doi":"10.1177/1042391510379807","DOIUrl":"https://doi.org/10.1177/1042391510379807","url":null,"abstract":"All existing simple entrainment calculation methods for the three-dimensional (3D) balcony spill plume assume that the mass flow rate of gases produced increases linearly with height of rise. It is recognized that at very large heights of rise the balcony spill plume will eventually behave like an axisymmetric plume in terms of entrainment behavior. The transition from a balcony spill plume to axisymmetric has not been rigorously studied and current guidance can only be considered to be an estimate. To remedy this situation, a general approach similar to that used in previous work is utilized to develop a simple approximation that predicts the height of transition in entrainment behavior. This type of analysis is further supported with a limited number of simulations using numerical modeling. The proposed simple approximation provides an upper height limit for which linearly based 3D balcony spill plume entrainment formulae can successfully be applied.","PeriodicalId":50192,"journal":{"name":"Journal of Fire Protection Engineering","volume":"20 1","pages":"273-289"},"PeriodicalIF":0.0,"publicationDate":"2010-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1177/1042391510379807","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"65326035","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 : 2010-11-01DOI: 10.1177/1042391510367349
Xiaocui Zhang, Manjiang Yang, Jian Wang, Yaping He
Computational fluid dynamics (CFD) modeling (or field modeling) is becoming the main method for numerical simulation of building fires. Among many factors that influence the validity and accuracy of CFD simulation results, the computational domain is sometimes overlooked. In this article, the effects of computational domain on simulation results are analyzed. Simulation results from the use of different domains are compared with experimental data reported in the literature. A parametric study is then conducted to reveal a relationship between the effective domain extension and the heat release rate of the enclosure fire. The effect of computational domain extension in relation to vent opening is also investigated. It is found that the selection of computational domain can have a significant effect on the outcome of enclosure fire simulations. Determination of the appropriate computational domain without unduly sacrificing computational efficiency is also discussed.
{"title":"Effects of Computational Domain on Numerical Simulation of Building Fires","authors":"Xiaocui Zhang, Manjiang Yang, Jian Wang, Yaping He","doi":"10.1177/1042391510367349","DOIUrl":"https://doi.org/10.1177/1042391510367349","url":null,"abstract":"Computational fluid dynamics (CFD) modeling (or field modeling) is becoming the main method for numerical simulation of building fires. Among many factors that influence the validity and accuracy of CFD simulation results, the computational domain is sometimes overlooked. In this article, the effects of computational domain on simulation results are analyzed. Simulation results from the use of different domains are compared with experimental data reported in the literature. A parametric study is then conducted to reveal a relationship between the effective domain extension and the heat release rate of the enclosure fire. The effect of computational domain extension in relation to vent opening is also investigated. It is found that the selection of computational domain can have a significant effect on the outcome of enclosure fire simulations. Determination of the appropriate computational domain without unduly sacrificing computational efficiency is also discussed.","PeriodicalId":50192,"journal":{"name":"Journal of Fire Protection Engineering","volume":"20 1","pages":"225-251"},"PeriodicalIF":0.0,"publicationDate":"2010-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1177/1042391510367349","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"65326194","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 : 2010-10-04DOI: 10.1177/1042391510380139
Puneet Sharma, J. Quintiere
The temperature of the hot gases during a compartment fire is important to practitioners of fire protection engineering. The classic MQH correlation provides a simple and quick estimate of this temperature. An alternate model for compartment fire temperature is proposed based on an energy balance and an empirical mass flow rate formula. This model accounts for highly insulated boundary conditions and is valid for higher (>600°C) temperatures, which are two major limitations with the MQH correlation. The transition of a compartment fire to a ventilation-limited state is then analyzed to find the maximum gas temperatures. The analysis provides the maximum temperature possible for a design fire with two important variables — vent size and thermal properties of the wall material. The effects of these two variables are investigated by assuming commonly specified wall materials and different vent sizes, thereby showing the applicability of this approach for fire engineering.
{"title":"Compartment Fire Temperatures","authors":"Puneet Sharma, J. Quintiere","doi":"10.1177/1042391510380139","DOIUrl":"https://doi.org/10.1177/1042391510380139","url":null,"abstract":"The temperature of the hot gases during a compartment fire is important to practitioners of fire protection engineering. The classic MQH correlation provides a simple and quick estimate of this temperature. An alternate model for compartment fire temperature is proposed based on an energy balance and an empirical mass flow rate formula. This model accounts for highly insulated boundary conditions and is valid for higher (>600°C) temperatures, which are two major limitations with the MQH correlation. The transition of a compartment fire to a ventilation-limited state is then analyzed to find the maximum gas temperatures. The analysis provides the maximum temperature possible for a design fire with two important variables — vent size and thermal properties of the wall material. The effects of these two variables are investigated by assuming commonly specified wall materials and different vent sizes, thereby showing the applicability of this approach for fire engineering.","PeriodicalId":50192,"journal":{"name":"Journal of Fire Protection Engineering","volume":"20 1","pages":"253-271"},"PeriodicalIF":0.0,"publicationDate":"2010-10-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1177/1042391510380139","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"65326349","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 : 2010-08-01DOI: 10.1177/1042391510367359
J. Trelles, J. Mawhinney
A series of full-scale fire suppression tests was conducted at the San Pedro de Anes test tunnel facility near Gijon, Asturias, Spain in February 2006. The fuel was wooden pallets or a mixed load of wood and high density polyethylene pallets. Fire protection was provided by water mist systems in different configurations. Because of facility restrictions, some scenarios of great interest, such as a free burn fire, could not be investigated. However, in order to complement the experimental results, a number of computational fluid dynamics simulations were conducted on a 140 m section of the tunnel facility. The Fire Dynamics Simulator, version 4, was used for the numerical investigation. An algorithm was developed to allow the fire to spread along the top of a series of pallet loads in such a way that the measured heat release rate was reproduced. Verification and validation studies confirmed that the model predicted the measured ventilation speeds and peak temperatures. The agreement between the simulations and the field measurements was very good prior to activation of the water mist. Back-layering was modeled well. After activation of the mist, the simulations predicted a large drop in gas temperatures, and retreat of the back-layer, but under-predicted the thermal cooling by the water mist downstream of the fire. With the suppression system, high temperatures and heat fluxes were limited to the immediate vicinity of the burning pallets. The model was then used to simulate a free burn fire in the tunnel. The simulation demonstrated the catastrophic conditions created by an unsuppressed fire in a tunnel when compared against the thermally managed conditions under suppressed conditions.
2006年2月，在西班牙阿斯图里亚斯希洪附近的San Pedro de Anes试验隧道设施进行了一系列全面灭火试验。燃料是木制托盘或混合负载的木材和高密度聚乙烯托盘。消防是由不同配置的水雾系统提供的。由于设施的限制，一些非常有趣的场景，如自由燃烧火灾，无法进行调查。然而，为了补充实验结果，在隧道设施的140 m段进行了一些计算流体动力学模拟。数值研究使用了Fire Dynamics Simulator第4版。开发了一种算法，允许火灾沿着一系列托盘负载的顶部蔓延，以这样一种方式再现测量的热释放率。验证和验证研究证实，该模型预测了测量的通风速度和峰值温度。在水雾激活之前，模拟结果与现场测量结果吻合良好。反向分层建模得很好。在雾被激活后，模拟预测了气体温度的大幅下降和后层的退缩，但对火灾下游水雾的热冷却的预测不足。有了抑制系统，高温和热流被限制在燃烧托盘的直接附近。然后用该模型模拟了隧道内的自由燃烧火灾。模拟结果显示了隧道中未被抑制的火灾与被抑制条件下的热管理条件相比所产生的灾难性条件。
{"title":"CFD Investigation of Large Scale Pallet Stack Fires in Tunnels Protected by Water Mist Systems","authors":"J. Trelles, J. Mawhinney","doi":"10.1177/1042391510367359","DOIUrl":"https://doi.org/10.1177/1042391510367359","url":null,"abstract":"A series of full-scale fire suppression tests was conducted at the San Pedro de Anes test tunnel facility near Gijon, Asturias, Spain in February 2006. The fuel was wooden pallets or a mixed load of wood and high density polyethylene pallets. Fire protection was provided by water mist systems in different configurations. Because of facility restrictions, some scenarios of great interest, such as a free burn fire, could not be investigated. However, in order to complement the experimental results, a number of computational fluid dynamics simulations were conducted on a 140 m section of the tunnel facility. The Fire Dynamics Simulator, version 4, was used for the numerical investigation. An algorithm was developed to allow the fire to spread along the top of a series of pallet loads in such a way that the measured heat release rate was reproduced. Verification and validation studies confirmed that the model predicted the measured ventilation speeds and peak temperatures. The agreement between the simulations and the field measurements was very good prior to activation of the water mist. Back-layering was modeled well. After activation of the mist, the simulations predicted a large drop in gas temperatures, and retreat of the back-layer, but under-predicted the thermal cooling by the water mist downstream of the fire. With the suppression system, high temperatures and heat fluxes were limited to the immediate vicinity of the burning pallets. The model was then used to simulate a free burn fire in the tunnel. The simulation demonstrated the catastrophic conditions created by an unsuppressed fire in a tunnel when compared against the thermally managed conditions under suppressed conditions.","PeriodicalId":50192,"journal":{"name":"Journal of Fire Protection Engineering","volume":"20 1","pages":"149-198"},"PeriodicalIF":0.0,"publicationDate":"2010-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1177/1042391510367359","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"65325787","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 : 2010-08-01DOI: 10.1177/1042391510372726
Yaping He
In response to the call for the development of risk informed, performance-based building fire regulations, a literature review was conducted to link the traditional safety factor approach in fire safety engineering to failure probability. It can be demonstrated that a safety factor alone is an insufficient measure, or is only a first-order measure of risk or failure probability. To achieve a higher order estimate of failure probability, an α-percentile method is proposed. As part of this methodology, it is also proposed that the fire engineering briefing process involve nominations of percentile values for design fire scenarios as well as other parameters that define the scenarios.
{"title":"Linking Safety Factor and Failure Probability for Fire Safety Engineering","authors":"Yaping He","doi":"10.1177/1042391510372726","DOIUrl":"https://doi.org/10.1177/1042391510372726","url":null,"abstract":"In response to the call for the development of risk informed, performance-based building fire regulations, a literature review was conducted to link the traditional safety factor approach in fire safety engineering to failure probability. It can be demonstrated that a safety factor alone is an insufficient measure, or is only a first-order measure of risk or failure probability. To achieve a higher order estimate of failure probability, an α-percentile method is proposed. As part of this methodology, it is also proposed that the fire engineering briefing process involve nominations of percentile values for design fire scenarios as well as other parameters that define the scenarios.","PeriodicalId":50192,"journal":{"name":"Journal of Fire Protection Engineering","volume":"20 1","pages":"199-217"},"PeriodicalIF":0.0,"publicationDate":"2010-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1177/1042391510372726","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"65325968","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 : 2010-05-01DOI: 10.1177/1042391509344243
P. Tofilo, M. Delichatsios
A thorough examination has been performed of the thermally induced stresses on a window in an enclosure-fire environment. Analytical and numerical methods establish the importance of bridling stress (due to axial elongation) and flexing stress (due to normal deformation). Most previous studies omitted the consideration of flexing stresses. Maximum stresses, being the sum of bridling and flexing stresses on the side, have been calculated for varying aspect ratios of a rectangular window and for varying ratios of shaded width to the window sides. For uniform width and heating (e.g., represented, by constant high temperature in the heated region and ambient temperature in the shaded region), the maximum stresses are bridling and equal to those of an infinite strip shaded on two sides when the shaded width is less than 40% of the short side. For nonuniform shading (e.g., due to radiation blockage) or nonuniform heating, flexing stresses contribute to the total stress by an increase up to 50%. These new results have been applied in predicting the magnitude of stresses and the location of the first crack in well-controlled experiments and measurements. These results are important because they extend and delineate the limitations of currently used relations for determining thermally induced stresses and times of first cracking in windows.
{"title":"Thermally Induced Stresses in Glazing Systems","authors":"P. Tofilo, M. Delichatsios","doi":"10.1177/1042391509344243","DOIUrl":"https://doi.org/10.1177/1042391509344243","url":null,"abstract":"A thorough examination has been performed of the thermally induced stresses on a window in an enclosure-fire environment. Analytical and numerical methods establish the importance of bridling stress (due to axial elongation) and flexing stress (due to normal deformation). Most previous studies omitted the consideration of flexing stresses. Maximum stresses, being the sum of bridling and flexing stresses on the side, have been calculated for varying aspect ratios of a rectangular window and for varying ratios of shaded width to the window sides. For uniform width and heating (e.g., represented, by constant high temperature in the heated region and ambient temperature in the shaded region), the maximum stresses are bridling and equal to those of an infinite strip shaded on two sides when the shaded width is less than 40% of the short side. For nonuniform shading (e.g., due to radiation blockage) or nonuniform heating, flexing stresses contribute to the total stress by an increase up to 50%. These new results have been applied in predicting the magnitude of stresses and the location of the first crack in well-controlled experiments and measurements. These results are important because they extend and delineate the limitations of currently used relations for determining thermally induced stresses and times of first cracking in windows.","PeriodicalId":50192,"journal":{"name":"Journal of Fire Protection Engineering","volume":"20 1","pages":"101-116"},"PeriodicalIF":0.0,"publicationDate":"2010-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1177/1042391509344243","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"65325454","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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