Pub Date : 2024-09-06DOI: 10.1177/07349041241268991
XY Liu, MX Ma, ZL Wei, HS Zhen, YL Wang
Driven by the necessity to understand the fire and smoke dispersion characteristics of electric bicycle (escooter) fires and their effects on residents’ safety in rural houses, this study was conducted to perform full-scale fire experiments in a village house in Hainan, People’s Republic of China. The tested building is a typical multi-story building representative of rural houses in southern China. It is found that an escooter fire grows rapidly once its lithium-ion battery is overcharged to ignite. Inside the stairwell where the escooters are parked, a significant increase in temperature over 60°C across all floors is observed and the maximum temperature reaches up to 800°C on the first floor. Furthermore, the propagation of smoke is fast, reaching the upper floors within 5 minutes and filling the entire building within 7 minutes. Due to stack effect, carbon monoxide concentration is the highest on the fourth floor, notably higher than the other floors. Closing the doors of rooms where occupants are typically present is found to effectively block heat and smoke transfer. Thus, in case an escooter’s lithium-ion battery undergoes explosion combustion, it is better that residents stay in rooms by closing or even sealing the doors, waiting for help during most of the fire period. However, in case the lithium-ion battery has not been burning, there still are chances for evacuation or putting out the flame.
{"title":"An experimental case study of escooter fire in a four-story building","authors":"XY Liu, MX Ma, ZL Wei, HS Zhen, YL Wang","doi":"10.1177/07349041241268991","DOIUrl":"https://doi.org/10.1177/07349041241268991","url":null,"abstract":"Driven by the necessity to understand the fire and smoke dispersion characteristics of electric bicycle (escooter) fires and their effects on residents’ safety in rural houses, this study was conducted to perform full-scale fire experiments in a village house in Hainan, People’s Republic of China. The tested building is a typical multi-story building representative of rural houses in southern China. It is found that an escooter fire grows rapidly once its lithium-ion battery is overcharged to ignite. Inside the stairwell where the escooters are parked, a significant increase in temperature over 60°C across all floors is observed and the maximum temperature reaches up to 800°C on the first floor. Furthermore, the propagation of smoke is fast, reaching the upper floors within 5 minutes and filling the entire building within 7 minutes. Due to stack effect, carbon monoxide concentration is the highest on the fourth floor, notably higher than the other floors. Closing the doors of rooms where occupants are typically present is found to effectively block heat and smoke transfer. Thus, in case an escooter’s lithium-ion battery undergoes explosion combustion, it is better that residents stay in rooms by closing or even sealing the doors, waiting for help during most of the fire period. However, in case the lithium-ion battery has not been burning, there still are chances for evacuation or putting out the flame.","PeriodicalId":15772,"journal":{"name":"Journal of Fire Sciences","volume":null,"pages":null},"PeriodicalIF":1.9,"publicationDate":"2024-09-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142192902","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-07-27DOI: 10.1177/07349041241263507
Richard E Lyon
The fire growth rate of interior linings, furnishings, and construction materials is measured in full-scale fire tests such as the ASTM E84 Steiner Tunnel, the ISO 9705 room fire, and a passenger aircraft fuselage as the flame-spread rate, time-to-flashover, or time to incapacitation, respectively. The results are used to indicate the level of passive fire protection afforded by the combustible material or product in the test without providing any insight into the burning process. These large-scale tests require many square meters of product, are very expensive to conduct, and can exhibit poor repeatability–making them unsuitable for product development, quality control, product surveillance, or regulatory compliance. For this reason, smaller (0.01 m2) samples are tested in bench-scale fire calorimeters under controlled conditions, and these one-dimensional burning histories are correlated with the results of the two- and three-dimensional burning histories in full-scale fire tests by a variety of empirical and semi-empirical fire propagation indices, as well as analytic and computer models specific to the full-scale fire test. The approach described here defines the potential of a material to grow a fire in terms of cone calorimeter data obtained under standard conditions. The fire growth potential, λ (m2/J), is the coupled process of surface flame spread and in-depth burning that is defined as the product of ignitability (1/ E ign) and combustibility (Δ Q/Δ E) obtained from a combustion energy diagram measured in a cone calorimeter at an external radiant energy flux [Formula: see text] (W/m2) above the critical flux for burning, [Formula: see text]. However, the potential for fire growth, λ≡ (1/ Ei gn)(Δ Q/Δ E) is only realized as a hazard when the heat of combustion of the product per unit surface area, Hc (J/m2), is sufficient to grow the fire. The dimensionless fire hazard of a combustible product of thickness b is therefore, Π = λ Hc, while the fire hazard of the component materials is an average over the product thickness, π = Π/ b. The measurement of λ, Π, and π from combustion energy diagrams of heat release Q (J/m2) versus incident energy E (J/m2) is described, as well as a physical basis for a fire growth potential that provides simple analytic forms for λ in terms of the parameters reported in cone calorimeter tests. Experimental data from the literature show that rapid fire growth in full-scale fire tests of combustible materials occurs above a value of Π determined by the severity of the fire test.
内衬、家具和建筑材料的火灾增长率是在全面火灾测试中测量的，如 ASTM E84 斯坦纳隧道、ISO 9705 室内火灾和客机机身，分别测量为火焰蔓延率、燃烧时间或丧失能力时间。测试结果用于说明可燃材料或产品在测试中提供的被动防火水平，而不提供任何有关燃烧过程的信息。这些大型测试需要很多平方米的产品，成本非常高，而且重复性差，因此不适合用于产品开发、质量控制、产品监督或法规遵从。因此，较小（0.01 平方米）的样品要在受控条件下用台式火烧热量计进行测试，并通过各种经验和半经验火灾传播指数以及专门针对全尺寸火烧测试的分析和计算机模型，将这些一维燃烧历史与全尺寸火烧测试中的二维和三维燃烧历史结果联系起来。这里介绍的方法是根据在标准条件下获得的锥形量热计数据来定义材料的火势增长潜力。火势增长潜力 λ (m2/J) 是表面火焰蔓延和深度燃烧的耦合过程，定义为可燃性（1/ E ign）和可燃性（Δ Q/Δ E）的乘积，该乘积是在外部辐射能量通量[计算公式：见正文]（W/m2）高于燃烧临界通量[计算公式：见正文]的情况下，从锥形量热计测量的燃烧能量图中获得的。然而，只有当单位表面积产品的燃烧热 Hc (J/m2) 足以使火势蔓延时，火势蔓延的可能性 λ≡ (1/ Ei gn)(Δ Q/Δ E) 才会成为一种危险。因此，厚度为 b 的可燃产品的无量纲火灾危险性为 Π = λ Hc，而组成材料的火灾危险性为产品厚度的平均值 π = Π/ b。本文介绍了通过燃烧能量图（热释放 Q (J/m2) 与入射能量 E (J/m2)）测量 λ、Π 和 π 的方法，以及火灾增长势能的物理基础，该基础可根据锥形量热计测试报告的参数提供 λ 的简单解析形式。文献中的实验数据表明，在可燃材料的全尺寸火灾试验中，火灾的快速增长发生在火灾试验严重程度所决定的 Π 值之上。
{"title":"Measuring the fire growth potential of combustible solids using a cone calorimeter","authors":"Richard E Lyon","doi":"10.1177/07349041241263507","DOIUrl":"https://doi.org/10.1177/07349041241263507","url":null,"abstract":"The fire growth rate of interior linings, furnishings, and construction materials is measured in full-scale fire tests such as the ASTM E84 Steiner Tunnel, the ISO 9705 room fire, and a passenger aircraft fuselage as the flame-spread rate, time-to-flashover, or time to incapacitation, respectively. The results are used to indicate the level of passive fire protection afforded by the combustible material or product in the test without providing any insight into the burning process. These large-scale tests require many square meters of product, are very expensive to conduct, and can exhibit poor repeatability–making them unsuitable for product development, quality control, product surveillance, or regulatory compliance. For this reason, smaller (0.01 m2) samples are tested in bench-scale fire calorimeters under controlled conditions, and these one-dimensional burning histories are correlated with the results of the two- and three-dimensional burning histories in full-scale fire tests by a variety of empirical and semi-empirical fire propagation indices, as well as analytic and computer models specific to the full-scale fire test. The approach described here defines the potential of a material to grow a fire in terms of cone calorimeter data obtained under standard conditions. The fire growth potential, λ (m2/J), is the coupled process of surface flame spread and in-depth burning that is defined as the product of ignitability (1/ E ign) and combustibility (Δ Q/Δ E) obtained from a combustion energy diagram measured in a cone calorimeter at an external radiant energy flux [Formula: see text] (W/m2) above the critical flux for burning, [Formula: see text]. However, the potential for fire growth, λ≡ (1/ Ei gn)(Δ Q/Δ E) is only realized as a hazard when the heat of combustion of the product per unit surface area, Hc (J/m2), is sufficient to grow the fire. The dimensionless fire hazard of a combustible product of thickness b is therefore, Π = λ Hc, while the fire hazard of the component materials is an average over the product thickness, π = Π/ b. The measurement of λ, Π, and π from combustion energy diagrams of heat release Q (J/m2) versus incident energy E (J/m2) is described, as well as a physical basis for a fire growth potential that provides simple analytic forms for λ in terms of the parameters reported in cone calorimeter tests. Experimental data from the literature show that rapid fire growth in full-scale fire tests of combustible materials occurs above a value of Π determined by the severity of the fire test.","PeriodicalId":15772,"journal":{"name":"Journal of Fire Sciences","volume":null,"pages":null},"PeriodicalIF":1.9,"publicationDate":"2024-07-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141797992","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-07-26DOI: 10.1177/07349041241259989
Mingwei Tang, Thomas Rogaume, Benjamin Batiot, Tsilla Bensabath, Serge Bourbigot
The project aimed to develop a reduced scale test protocol designed to be repeatable and capable of providing the upward fire evaluation for assessing fire risk on external thermal insulation composite system facade samples. The variation of heat flux is simulated by radiant panel. This experimental setup permits the recording of dynamic variables in flame propagation, such as ignition time, flame extinguishing time, and variations in both surface and back temperatures of the insulation panel. Notably, the measurement of back temperature provides a means to assess the thermal insulation efficiency of the external thermal insulation composite system facade. Furthermore, the fire spreading temperature is collected during the test could also be useful for larger-scale testing.
{"title":"Reduced scale test bench for investigating the upward flame heat impact on external thermal insulation composite system facades","authors":"Mingwei Tang, Thomas Rogaume, Benjamin Batiot, Tsilla Bensabath, Serge Bourbigot","doi":"10.1177/07349041241259989","DOIUrl":"https://doi.org/10.1177/07349041241259989","url":null,"abstract":"The project aimed to develop a reduced scale test protocol designed to be repeatable and capable of providing the upward fire evaluation for assessing fire risk on external thermal insulation composite system facade samples. The variation of heat flux is simulated by radiant panel. This experimental setup permits the recording of dynamic variables in flame propagation, such as ignition time, flame extinguishing time, and variations in both surface and back temperatures of the insulation panel. Notably, the measurement of back temperature provides a means to assess the thermal insulation efficiency of the external thermal insulation composite system facade. Furthermore, the fire spreading temperature is collected during the test could also be useful for larger-scale testing.","PeriodicalId":15772,"journal":{"name":"Journal of Fire Sciences","volume":null,"pages":null},"PeriodicalIF":1.9,"publicationDate":"2024-07-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141779566","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-06-10DOI: 10.1177/07349041241256986
Jiuling Yang, Xiaofeng Peng, James Urban, Wei Huang, Haoliang Wang, Shaojia Wang, Yuqi Hu
Despite the increasing frequency in spot ignition by embers in wildfires, research on the multiple physicochemical processes intrinsic to ember combustion is limited. In this study, a two-dimensional computational model was proposed to study the glowing combustion of a wooden ember. A global char oxidation reaction was used to represent the glowing combustion of the ember. A parametric study showed that the porosity, heat of reaction, and oxygen concentration were the most influential parameters on the ember combustion. Then, the model was compared to a series of bench-scale experiments in terms of glowing time and thermal response of a non-reacting substrate when exposed to a hot ember. The simulation results showed that ember combustion was mostly diffusion-controlled rather than kinetic-controlled. Thus, given the ember diversities in spotting fire, modelers should pay more attention to the difference in the physical properties instead of the kinetics between ember species.
{"title":"Computational study on the glowing combustion of a wooden ember landing on a non-reacting substrate","authors":"Jiuling Yang, Xiaofeng Peng, James Urban, Wei Huang, Haoliang Wang, Shaojia Wang, Yuqi Hu","doi":"10.1177/07349041241256986","DOIUrl":"https://doi.org/10.1177/07349041241256986","url":null,"abstract":"Despite the increasing frequency in spot ignition by embers in wildfires, research on the multiple physicochemical processes intrinsic to ember combustion is limited. In this study, a two-dimensional computational model was proposed to study the glowing combustion of a wooden ember. A global char oxidation reaction was used to represent the glowing combustion of the ember. A parametric study showed that the porosity, heat of reaction, and oxygen concentration were the most influential parameters on the ember combustion. Then, the model was compared to a series of bench-scale experiments in terms of glowing time and thermal response of a non-reacting substrate when exposed to a hot ember. The simulation results showed that ember combustion was mostly diffusion-controlled rather than kinetic-controlled. Thus, given the ember diversities in spotting fire, modelers should pay more attention to the difference in the physical properties instead of the kinetics between ember species.","PeriodicalId":15772,"journal":{"name":"Journal of Fire Sciences","volume":null,"pages":null},"PeriodicalIF":1.9,"publicationDate":"2024-06-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141360968","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-06-10DOI: 10.1177/07349041241256796
H. Prétrel, S. Vaux
This work deals with smoke propagation through a multi-compartment assembly in case of a fire event in a nuclear installation. The scientific issues are the understanding of flows involving two modes of propagation (vent and doorway), together with the role of mechanical ventilation and oxygen backflows to the fire. The study is based on the analysis of two scenarios reproduced experimentally at large scale and simulated numerically. The main outcomes concern the comparison of the flow at a doorway and at a vent, the consequence of the smoke propagation for thermal stratification and the combined effect of the fire heat release rate and mechanical ventilation. The results highlight the performance of computational fluid dynamics simulations in predicting these complex scenarios. Low-velocity flow zones are identified, enabling the structure of these flows and their amplitudes to be quantified. This information provides new insights to improve fire risk assessment in nuclear facilities.
{"title":"Fire-induced flows for complex fire scenarios in a mechanically ventilated two-storey structure","authors":"H. Prétrel, S. Vaux","doi":"10.1177/07349041241256796","DOIUrl":"https://doi.org/10.1177/07349041241256796","url":null,"abstract":"This work deals with smoke propagation through a multi-compartment assembly in case of a fire event in a nuclear installation. The scientific issues are the understanding of flows involving two modes of propagation (vent and doorway), together with the role of mechanical ventilation and oxygen backflows to the fire. The study is based on the analysis of two scenarios reproduced experimentally at large scale and simulated numerically. The main outcomes concern the comparison of the flow at a doorway and at a vent, the consequence of the smoke propagation for thermal stratification and the combined effect of the fire heat release rate and mechanical ventilation. The results highlight the performance of computational fluid dynamics simulations in predicting these complex scenarios. Low-velocity flow zones are identified, enabling the structure of these flows and their amplitudes to be quantified. This information provides new insights to improve fire risk assessment in nuclear facilities.","PeriodicalId":15772,"journal":{"name":"Journal of Fire Sciences","volume":null,"pages":null},"PeriodicalIF":1.9,"publicationDate":"2024-06-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141363405","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-06-06DOI: 10.1177/07349041241257262
M. Khelifa, Trong Tuan Tran, A. Khennane, M. Oudjène, Y. Rogaume
A new type of timber connection using densified wood dowels is being developed and tested. The procedure involves inserting these densified dowels into pre-drilled holes. As this connection technique is in its early stages, a unique design approach is necessary, considering the impact of temperature variations. The primary goal is to characterize the thermal behaviour of these connections under elevated temperatures. The study employs an experimental approach, complemented by numerical analysis, innovatively applying kinetic models, commonly used for investigating heat-related biomass characteristics, to wood. The method requires the use of thermogravimetric analysis to identify the kinetic parameters. The proposed pyrolysis kinetic model has been implemented in the Abaqus/Implicit code via a user subroutine UMATHT. The study concludes that using kinetic models enhances accuracy by considering mass loss, a key factor influencing thermal properties. Simulation successfully replicates temperature distribution and charred layer thickness, crucial for designing timber structures.
{"title":"Thermal response of timber connections using densified wood dowels under fire","authors":"M. Khelifa, Trong Tuan Tran, A. Khennane, M. Oudjène, Y. Rogaume","doi":"10.1177/07349041241257262","DOIUrl":"https://doi.org/10.1177/07349041241257262","url":null,"abstract":"A new type of timber connection using densified wood dowels is being developed and tested. The procedure involves inserting these densified dowels into pre-drilled holes. As this connection technique is in its early stages, a unique design approach is necessary, considering the impact of temperature variations. The primary goal is to characterize the thermal behaviour of these connections under elevated temperatures. The study employs an experimental approach, complemented by numerical analysis, innovatively applying kinetic models, commonly used for investigating heat-related biomass characteristics, to wood. The method requires the use of thermogravimetric analysis to identify the kinetic parameters. The proposed pyrolysis kinetic model has been implemented in the Abaqus/Implicit code via a user subroutine UMATHT. The study concludes that using kinetic models enhances accuracy by considering mass loss, a key factor influencing thermal properties. Simulation successfully replicates temperature distribution and charred layer thickness, crucial for designing timber structures.","PeriodicalId":15772,"journal":{"name":"Journal of Fire Sciences","volume":null,"pages":null},"PeriodicalIF":1.9,"publicationDate":"2024-06-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141379712","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This study applies the Morris method for a sensitivity analysis to evaluate the input parameters’ influence on the heat release rate in a pyrolysis model, focusing on two materials, poly(methyl methacrylate) (non-charring) and poly(vinyl chloride) (charring), examined under a cone calorimeter. A key aspect of our exploration was the role of input parameter variation intervals on the sensitivity outcomes. We analyzed three interval-setting methods:1. A standard ±10% deviation from the nominal value, commonly used in the literature.2. A range determined by the experimental uncertainties for individual parameters.3. A span from minimum to maximum values found in existing literature for each parameter.Our intensive literature review supported the framing of intervals for the latter two methods. Our findings underscore the critical role of the selected variation interval. Specifically, while a uniform ±10% variation identified activation energies as the primary influencers—consistent with prior literature—the introduction of experimental uncertainties shifted this prominence toward heats of reaction. Thus, the selected interval can drastically reshape the perceived importance of certain parameters. This original work challenges the traditionally employed variation ranges in sensitivity studies, emphasizing the need for a nuanced approach.
{"title":"Influence of parameter variation intervals on pyrolysis sensitivity analysis for charring and non-charring materials","authors":"Abdenour Amokrane, Manon Fleurotte, Ali Hodroj, Olivier Authier, Gérald Debenest, Gaëlle Fontaine, Serge Bourbigot","doi":"10.1177/07349041241248080","DOIUrl":"https://doi.org/10.1177/07349041241248080","url":null,"abstract":"This study applies the Morris method for a sensitivity analysis to evaluate the input parameters’ influence on the heat release rate in a pyrolysis model, focusing on two materials, poly(methyl methacrylate) (non-charring) and poly(vinyl chloride) (charring), examined under a cone calorimeter. A key aspect of our exploration was the role of input parameter variation intervals on the sensitivity outcomes. We analyzed three interval-setting methods:1. A standard ±10% deviation from the nominal value, commonly used in the literature.2. A range determined by the experimental uncertainties for individual parameters.3. A span from minimum to maximum values found in existing literature for each parameter.Our intensive literature review supported the framing of intervals for the latter two methods. Our findings underscore the critical role of the selected variation interval. Specifically, while a uniform ±10% variation identified activation energies as the primary influencers—consistent with prior literature—the introduction of experimental uncertainties shifted this prominence toward heats of reaction. Thus, the selected interval can drastically reshape the perceived importance of certain parameters. This original work challenges the traditionally employed variation ranges in sensitivity studies, emphasizing the need for a nuanced approach.","PeriodicalId":15772,"journal":{"name":"Journal of Fire Sciences","volume":null,"pages":null},"PeriodicalIF":1.9,"publicationDate":"2024-05-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141167944","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-05-01DOI: 10.1177/07349041241249635
Lucas M Kekana, Joseph KO Asante, Bonex Mwakikunga
Fire performance measurements of one of the most used firefighting protective ensembles (also called turnout gears), in terms of thermal and smoke hazards, were determined with the cone calorimeter, that of thermal stability were determined with thermogravimetric analyzer, the physical inspection (physical degradation) of the surface done with the scanning electron microscopy, and energy dispersive spectroscopy measurements determined the elemental compositions of the detergent used in washing and the residual elements in the turnout gears. The cone calorimeter results indicated that the values of the thermal performance parameters, namely: peak heat release rate, maximum average rate of heat emission, and fire growth rate index, all decrease with increasing number of washing cycles, while the smoke parameters: peak smoke production rate, smoke growth rate index, total smoke release, and related sustained flaming values, all increase with increasing number of washing cycles. From the thermogravimetric analyzer measurements, the thermal stability of the turnout gears decrease with increasing number of washings.
{"title":"The effect of repeated washings on thermal protective performances of one most used structural firefighting turnout gear in the Gauteng Province in South Africa","authors":"Lucas M Kekana, Joseph KO Asante, Bonex Mwakikunga","doi":"10.1177/07349041241249635","DOIUrl":"https://doi.org/10.1177/07349041241249635","url":null,"abstract":"Fire performance measurements of one of the most used firefighting protective ensembles (also called turnout gears), in terms of thermal and smoke hazards, were determined with the cone calorimeter, that of thermal stability were determined with thermogravimetric analyzer, the physical inspection (physical degradation) of the surface done with the scanning electron microscopy, and energy dispersive spectroscopy measurements determined the elemental compositions of the detergent used in washing and the residual elements in the turnout gears. The cone calorimeter results indicated that the values of the thermal performance parameters, namely: peak heat release rate, maximum average rate of heat emission, and fire growth rate index, all decrease with increasing number of washing cycles, while the smoke parameters: peak smoke production rate, smoke growth rate index, total smoke release, and related sustained flaming values, all increase with increasing number of washing cycles. From the thermogravimetric analyzer measurements, the thermal stability of the turnout gears decrease with increasing number of washings.","PeriodicalId":15772,"journal":{"name":"Journal of Fire Sciences","volume":null,"pages":null},"PeriodicalIF":1.9,"publicationDate":"2024-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140835621","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-04-26DOI: 10.1177/07349041241245697
Matthieu Caron, Karima Ben Tayeb, Serge Bourbigot, Gaëlle Fontaine
The mixture of ammonium polyphosphate and pentaerythritol is a very efficient intumescent system suitable for polyolefins, especially polypropylene. In this article, the intumescence mechanism of this intumescent system with and without zeolite 4A used as a synergy agent is revisited. The intumescent system was investigated in depth using continuous-wave electron paramagnetic resonance spectroscopy, solid-state nuclear magnetic resonance, and the advanced technique, namely hyperfine sublevel correlation pulsed electron paramagnetic resonance. It was observed that the char generated between 250°C and 350°C is made of polycyclic heterocyclic radicals with nitrogen atoms and that free radicals are mainly generated at these temperatures with a spin concentration relatively stable at least up to 500°C. Moreover, the presence of hydrogen, carbon, nitrogen, and phosphorus was clearly evidenced in the chemical environment of free electrons at 350°C (hyperfine sublevel correlation pulsed electron paramagnetic resonance). Besides, it was also evidenced that 4A totally collapses below 250°C. Contrary to previous works suggesting the presence of aluminosilicophosphate complexes, this work demonstrated that distinct alumino- and silicophosphate complexes are generated and protected the residue at high temperatures.
{"title":"Re-examination of the intumescence mechanism of ammonium polyphosphate/pentaerythritol/zeolite 4A fire-retarded formulation using advanced spectroscopic techniques","authors":"Matthieu Caron, Karima Ben Tayeb, Serge Bourbigot, Gaëlle Fontaine","doi":"10.1177/07349041241245697","DOIUrl":"https://doi.org/10.1177/07349041241245697","url":null,"abstract":"The mixture of ammonium polyphosphate and pentaerythritol is a very efficient intumescent system suitable for polyolefins, especially polypropylene. In this article, the intumescence mechanism of this intumescent system with and without zeolite 4A used as a synergy agent is revisited. The intumescent system was investigated in depth using continuous-wave electron paramagnetic resonance spectroscopy, solid-state nuclear magnetic resonance, and the advanced technique, namely hyperfine sublevel correlation pulsed electron paramagnetic resonance. It was observed that the char generated between 250°C and 350°C is made of polycyclic heterocyclic radicals with nitrogen atoms and that free radicals are mainly generated at these temperatures with a spin concentration relatively stable at least up to 500°C. Moreover, the presence of hydrogen, carbon, nitrogen, and phosphorus was clearly evidenced in the chemical environment of free electrons at 350°C (hyperfine sublevel correlation pulsed electron paramagnetic resonance). Besides, it was also evidenced that 4A totally collapses below 250°C. Contrary to previous works suggesting the presence of aluminosilicophosphate complexes, this work demonstrated that distinct alumino- and silicophosphate complexes are generated and protected the residue at high temperatures.","PeriodicalId":15772,"journal":{"name":"Journal of Fire Sciences","volume":null,"pages":null},"PeriodicalIF":1.9,"publicationDate":"2024-04-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140800477","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-04-25DOI: 10.1177/07349041241237517
Jason Floyd, Daniel Madrzykowski
In 2005, a line-of-duty death of an instructor at a firefighter training facility spawned research into both firefighter training and improving firefighter protective gear. Since the incident, there has been additional research into the material properties, firefighter facepiece performance, and the classification of firefighter exposures. This has been in parallel to significant improvements in the ability to model fires and predict, rather than prescribe, fire growth. As this recent body of work was not available at the time of incident investigation, the incident was revisited using the current version of Fire Dynamics Simulator. The full day of training evolutions was modeled in Fire Dynamics Simulator using recent data on wood pyrolysis (the fuel) and facepiece reaction to heat. Fire Dynamics Simulator results were evaluated against the testing done following the incident. Facepiece research was used to develop hole formation criteria that could be evaluated from Fire Dynamics Simulator predictions of facepiece exposure. This was used to compare the performance of facepieces contemporary with the incident to today’s facepieces. In addition, exposure predictions were evaluated in the context of exposure hazard categories developed for firefighter protective gear.
{"title":"Fire dynamics simulator modeling of a line-of-duty death in a firefighting training facility using recent research on materials and firefighter safety","authors":"Jason Floyd, Daniel Madrzykowski","doi":"10.1177/07349041241237517","DOIUrl":"https://doi.org/10.1177/07349041241237517","url":null,"abstract":"In 2005, a line-of-duty death of an instructor at a firefighter training facility spawned research into both firefighter training and improving firefighter protective gear. Since the incident, there has been additional research into the material properties, firefighter facepiece performance, and the classification of firefighter exposures. This has been in parallel to significant improvements in the ability to model fires and predict, rather than prescribe, fire growth. As this recent body of work was not available at the time of incident investigation, the incident was revisited using the current version of Fire Dynamics Simulator. The full day of training evolutions was modeled in Fire Dynamics Simulator using recent data on wood pyrolysis (the fuel) and facepiece reaction to heat. Fire Dynamics Simulator results were evaluated against the testing done following the incident. Facepiece research was used to develop hole formation criteria that could be evaluated from Fire Dynamics Simulator predictions of facepiece exposure. This was used to compare the performance of facepieces contemporary with the incident to today’s facepieces. In addition, exposure predictions were evaluated in the context of exposure hazard categories developed for firefighter protective gear.","PeriodicalId":15772,"journal":{"name":"Journal of Fire Sciences","volume":null,"pages":null},"PeriodicalIF":1.9,"publicationDate":"2024-04-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140653919","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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