Fire Safety Journal最新文献

Numerical investigation of the influence of thermal runaway modelling on car park fire hazard and application to a Lithium-ion Manganese Oxide battery 热失控模型对停车场火灾危险影响的数值研究及对锰氧化物锂离子电池的应用

IF 3.4 3区工程技术 Q2 ENGINEERING, CIVIL

Fire Safety Journal

Pub Date : 2024-11-13 DOI: 10.1016/j.firesaf.2024.104284

Pierre-Alexandre Barré , Pierre Carlotti , Augustin Guibaud

This article presents numerical simulations of a Nissan LEAF 2011 electric car fire inside a concrete parking facility. Variations in the thermo-chemical properties of thermal runaway are analysed, and the way they affect the heat received by the concrete structure and a nearby parked vehicle is evaluated. Three key parameters are identified: the composition of the gas flowing through the pressure vent, the associated flow rate, and the peak heat release rate. These parameters are established independently, and the model is closed by adjusting the stoichiometry of the combustion reaction of the vented gas. Four simulations are conducted to capture the uncertainty. The net heat flux and surface temperature on the concrete and on a neighbouring parked car are monitored during each simulation. The study includes a sensitivity analysis of the impact of input variables on the net heat fluxes and surface temperatures, and investigations are carried out to understand the role of internal heat release. Variations in the gaseous mixture composition, heat release rate, and internal heat release have little impact on the resulting thermal conditions around the burning car because the combustion of the polymers in the passenger cabin drives the total heat release rate.

本文介绍了对混凝土停车设施内日产 LEAF 2011 电动汽车起火的数值模拟。文章分析了热失控的热化学特性变化，并评估了这些变化对混凝土结构和附近停放车辆所接收热量的影响。确定了三个关键参数：流经压力通风口的气体成分、相关流速和峰值热释放率。这些参数是独立确定的，通过调整排出气体燃烧反应的化学计量来关闭模型。进行了四次模拟以捕捉不确定性。在每次模拟过程中，都会对混凝土和邻近停放汽车的净热通量和表面温度进行监测。研究包括输入变量对净热通量和表面温度影响的敏感性分析，以及了解内部热释放作用的调查。气体混合物成分、热释放率和内部热释放的变化对燃烧汽车周围产生的热条件影响很小，因为乘客舱内聚合物的燃烧驱动了总热释放率。

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引用次数: 0

Analysis of air consumption and moving speed by firefighters during full-scale search & rescue experiments in a tunnel 隧道内全面搜救实验中消防员的耗气量和移动速度分析

IF 3.4 3区工程技术 Q2 ENGINEERING, CIVIL

Fire Safety Journal

Pub Date : 2024-11-13 DOI: 10.1016/j.firesaf.2024.104290

K. Lambert , B. Merci

Experiments were carried out in a 420 m long dead-end tunnel to assess air consumption and movement speed. The operation consisted of a 417 m walk to locate and rescue a victim. Seven teams of 5 blindfolded firefighters were sent into the tunnel with a single-bottle SCBA, a stretcher and a mobility cane. 14 firefighters (i.e., 44 %) had to use ‘reserve air’. Hence it is not considered safe to carry out such an operation. However, all the crews noticed the sign that they used half of the available air in their bottle, so it is possible to start the S&R operation in a tunnel and safely return at the 175 bar mark. The average time to completion was 35.2 min. All crews became better at using the cane, leading to a higher average movement speed (0.50 m/s) out of the tunnel than into the tunnel (0.39 m/s). The average air consumption per walking meter was 2.20 L/m going in and 1.33 L/m going out. The average air consumption rate was 49.9L/min going into the tunnel and 38.9 L/min going out of the tunnel. It is shown that speed plays an important role. Faster firefighters have a lower total air consumption.

在一条长 420 米的死胡同隧道中进行了实验，以评估空气消耗量和移动速度。行动包括步行 417 米寻找和营救一名受害者。由 5 名蒙眼消防员组成的 7 个小组携带单瓶 SCBA、担架和移动手杖进入隧道。14 名消防员（即 44%）不得不使用 "备用空气"。因此，进行这样的操作并不安全。不过，所有人员都注意到了他们使用了瓶中一半可用空气的迹象，因此可以在隧道中开始 S&R 操作，并在 175 bar 刻度处安全返回。平均完成时间为 35.2 分钟。所有工作人员都更善于使用手杖，因此走出隧道的平均移动速度（0.50 米/秒）高于进入隧道的平均移动速度（0.39 米/秒）。每行走一米的平均耗气量为：进入隧道 2.20 升/米，离开隧道 1.33 升/米。进入隧道的平均耗气量为 49.9 升/分钟，走出隧道的平均耗气量为 38.9 升/分钟。结果表明，速度起着重要作用。速度较快的消防员总耗气量较低。

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引用次数: 0

Numerical simulation of fire spread in a large-scale open CLT compartment 大规模开放式 CLT 隔室火灾蔓延的数值模拟

IF 3.4 3区工程技术 Q2 ENGINEERING, CIVIL

Fire Safety Journal

Pub Date : 2024-11-09 DOI: 10.1016/j.firesaf.2024.104289

Lei Jiang , Andreas Sæter Bøe , Tian Li

Recent experiments have shown that exposed cross-laminated timber (CLT) can have a significant effect on the fire dynamics of large compartments. A simulation with the Fire Dynamic Simulator has been conducted to better understand the fire behaviour of open-plan compartments with exposed CLT. The simulation was set up to replicate a large-scale experiment, FRIC-02, with exposed CLT on the back wall and ceiling. The compartment was 95 m² (18.8 m × 5.0 m × 2.5 m), with one long wall open (opening factor 0.18 m^1/2). A continuous wood crib was used as the variable fuel load.

The characteristic results of FRIC-02 with a rapid fire development and non-symmetrical external flames were successfully reproduced. With the wind coming diagonally from behind, as in FRIC-02, the external flames emerged mainly out of one window. The flames covered the entire window height, which effectively inhibited the inflow of air through that window. The imbalance in air supply also created large temperature differences throughout the compartment. With no implementation of wind, external flames and temperatures were more symmetrical. Despite a good match to FRIC-02, the method still has several limitations, including the adaption of the burning rate to the feedback from surroundings.

最近的实验表明，裸露的交叉层压木材（CLT）会对大型隔间的火灾动态产生重大影响。我们利用火灾动态模拟器进行了模拟，以更好地了解带有外露 CLT 的开放式隔间的火灾行为。模拟的设置是为了复制大规模实验 FRIC-02，该实验在后墙和天花板上裸露了 CLT。隔间面积为 95 平方米（18.8 米 × 5.0 米 × 2.5 米），其中一面长墙是开放式的（开放系数为 0.18 米1/2）。试验成功地再现了 FRIC-02 的特征结果，即火灾发展迅速，外部火焰不对称。与 FRIC-02 一样，风从后方斜吹，外部火焰主要从一扇窗户喷出。火焰覆盖了整个窗户高度，这有效地抑制了空气从该窗户的流入。空气供应的不平衡也造成了整个车厢的巨大温差。在没有风的情况下，外部火焰和温度更加对称。尽管该方法与 FRIC-02 非常吻合，但仍有一些局限性，包括燃烧速度与周围环境反馈的适应性。

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引用次数: 0

Soot modeling in the numerical simulation of buoyant diffusion flames and fires—A review 浮力扩散火焰和火灾数值模拟中的烟尘建模--综述

IF 3.4 3区工程技术 Q2 ENGINEERING, CIVIL

Fire Safety Journal

Pub Date : 2024-11-08 DOI: 10.1016/j.firesaf.2024.104279

Shahrooz Motaghian, Tarek Beji

In this paper, the major soot modeling approaches used in the numerical simulation of buoyant turbulent flames and fires are reviewed. In the context of soot modeling in fire dynamics simulations, the constraints are discussed and linked to the development of suitable soot models. Since soot models have always been developed and evaluated using laminar flames, the genesis of soot models used for turbulent buoyant flames is discussed in detail in the context of laminar flames at first. One of the important subjects of semi-empirical soot models is the calibration of constants. In this study, the calibration and possible re-calibration of soot modeling expressions in later studies are comprehensively investigated. Afterward, the recent studies on the numerical simulations of turbulent sooty buoyant flames are reviewed and the utilized sub-modeling approaches are discussed.

本文综述了浮力湍流火焰和火灾数值模拟中使用的主要烟尘建模方法。就火灾动力学模拟中的烟尘建模而言，本文讨论了制约因素，并将其与开发合适的烟尘模型联系起来。由于烟尘模型一直是通过层流火焰来开发和评估的，因此首先在层流火焰的背景下详细讨论了用于湍流浮力火焰的烟尘模型的起源。半经验烟尘模型的重要课题之一是常数的校准。本研究全面探讨了烟尘模型表达式的校准和后期研究中可能进行的重新校准。随后，综述了近期关于湍流烟尘浮力火焰数值模拟的研究，并讨论了所采用的子建模方法。

引用次数: 0

Experimental study to assess the impact of different connection types on the fire resistance of composite concrete-topped CLT slabs 评估不同连接类型对复合混凝土顶 CLT 板耐火性影响的实验研究

IF 3.4 3区工程技术 Q2 ENGINEERING, CIVIL

Fire Safety Journal

Pub Date : 2024-11-06 DOI: 10.1016/j.firesaf.2024.104288

Lingzhu Chen , Mingqian Wang , Qingfeng Xu , Kent A. Harries , Xi Chen , Shun Xiao

This paper summarizes the results of an experimental study of fire resistance of composite concrete-topped cross-laminated timber (CT-CLT) slabs exposed to fire at their soffit. Six composite CT-CLT slabs and one untopped CLT slab were tested under ISO 834 standard fire exposure while subject to an applied load equal to 20 % of the slab ultimate capacity. Test variables included the type and configuration of shear connection between the topping and CLT. Large bending deflections were observed as the slabs reached their fire resistance. Although the untopped CLT slab exhibited a fire resistance of only 16 min, all CT-CLT exhibited fire resistance greater than 1 h. The improved behavior is attributed to the stiffer CT-CLT behavior. CT-CLT slabs exhibited delamination of the lowermost layer of the CLT following through-layer charring. Observed charring rates were approximately 46 mm/h. Observed charring depths were well-predicted by existing design standard-recommended equations. Importantly, the interface between the concrete topping and CLT remained close to 30 °C and never exceeded 65 °C in any test. This is a promising result for employing adhesive systems to affect composite behavior between the topping and CLT.

本文总结了一项关于混凝土加顶交叉层压木材（CT-CLT）复合楼板的耐火性能的实验研究结果。在 ISO 834 标准火灾暴露条件下，对六块复合 CT-CLT 板和一块无顶 CLT 板进行了测试，施加的荷载相当于板极限承载力的 20%。测试变量包括顶板和 CLT 之间剪切连接的类型和结构。当楼板达到耐火极限时，会出现较大的弯曲挠度。虽然未封顶的 CLT 板的耐火时间只有 16 分钟，但所有 CT-CLT 板的耐火时间都超过了 1 小时。CT-CLT 板在通层炭化后，CLT 的最下层出现分层。观察到的炭化速度约为 46 毫米/小时。观察到的炭化深度完全符合现有设计标准推荐公式的预测。重要的是，在任何测试中，混凝土面层和 CLT 之间的界面温度都保持在 30 °C 附近，从未超过 65 °C。对于采用粘合剂系统来影响顶层和 CLT 之间的复合行为来说，这是一个很有前景的结果。

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引用次数: 0

Electric cooktop fire incidents in Finland 芬兰的电灶火灾事故

IF 3.4 3区工程技术 Q2 ENGINEERING, CIVIL

Fire Safety Journal

Pub Date : 2024-11-05 DOI: 10.1016/j.firesaf.2024.104283

Laura Kuurne , Tarja Ojala , Marjaleena Aatamila

Cooking related fires contribute to one-fourth of residential building fires in Finland. However, their prevalence is often underestimated in statistics due to underreporting when individuals manage situations without fire service assistance. Despite their significance, cooktop fires remain inadequately studied, impeding our understanding of residential fire safety and the advancement of effective prevention measures. This study aims to provide a comprehensive evaluation of electric cooktop safety in Finland. It explores factors undermining safety, analyses materials contributing to hazards, assesses financial damages, and scrutinizes typical cooktop fire scenarios and prevention methods. Utilizing data from statistics (2016–2022), Safety Investigation Authority reports (1998–2022), media reviews (1.7.2020–30.6.2023), and insurance data (2017–2020), supplemented by two survey studies, this research identifies consistent causative factors across multiple data sources. Common factors include excessive items left on cooktops, unattended cooking, and unintentional activation of cooktops. Approximately three-quarters of cooktop fires go unreported to fire services, suggesting a significantly higher prevalence than recorded in statistics. Moreover, minimal use of stove safety devices exacerbates the issue. According to insurance company data, the costs caused by cooktop fires are significantly higher than those reported in official statistics. Implementing existing technology is crucial for reducing the frequency and consequences of these fires.

在芬兰，与烹饪有关的火灾占住宅建筑火灾的四分之一。然而，由于个人在没有消防服务协助的情况下处理火灾时漏报，统计数据往往低估了这些火灾的发生率。尽管灶台火灾非常重要，但对其研究仍然不足，这阻碍了我们对住宅消防安全的了解和有效预防措施的推进。本研究旨在对芬兰的电灶安全进行全面评估。它探讨了破坏安全的因素，分析了造成危害的材料，评估了经济损失，并仔细研究了典型的灶台火灾情况和预防方法。本研究利用统计数据（2016-2022 年）、安全调查局报告（1998-2022 年）、媒体评论（2020 年 7 月 1 日至 2023 年 6 月 30 日）和保险数据（2017-2020 年），并辅以两项调查研究，从多个数据源中找出了一致的致因。常见的因素包括灶台上放置过多物品、无人看管的烹饪以及无意中启动灶台。大约四分之三的灶台火灾没有向消防部门报告，这表明火灾发生率远远高于统计记录。此外，很少使用炉灶安全装置也加剧了这一问题。根据保险公司的数据，炉灶火灾造成的损失远远高于官方统计数字。采用现有技术对于降低这些火灾的频率和后果至关重要。

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引用次数: 0

Digitized fuel load survey in commercial and university office buildings for fire safety assessment 用于消防安全评估的商业和大学办公楼数字化燃料负荷调查

IF 3.4 3区工程技术 Q2 ENGINEERING, CIVIL

Fire Safety Journal

Pub Date : 2024-11-05 DOI: 10.1016/j.firesaf.2024.104287

Yifei Ding, Wai Kit Cheung, Yuxin Zhang, Xinyan Huang

Fuel load significantly affects fire development in compartments, and its design value derives from the statistical results of numerous surveys. This work enhances the fuel load database by employing a digitized survey method to assess 27 university and commercial offices in Hong Kong and Mainland, China. The results revealed significant differences in fuel load densities: university offices averaged 382 MJ/m² (SD: 297 MJ/m²) and commercial offices averaged 1804 MJ/m² (SD: 1319 MJ/m²). Moreover, it proposed an online questionnaire method to overcome onsite access limitations. Furthermore, it identified higher fuel load densities in commercial offices due to higher paper-made content and greater occupancy density than university offices. The fuel load of university offices was lower than that in previous surveys and design codes, while commercial fuel load was higher. Notably, there is an increasing tendency of fuel load density and plastic combustible composition over the years. Additionally, it considers that Gompertz distribution better fits cumulative probabilities of fuel load density data with a small sample size. Overall, it provides a valuable database for future fire scenario design, fire codes edition, and fire safety assessment and discusses future collaboration with AI applications.

燃料负荷对隔间的火灾发展有重大影响，其设计价值来自大量调查的统计结果。这项研究采用数字化调查方法，对香港和中国大陆的 27 所大学和商业办公室进行了评估，从而增强了燃料负荷数据库。结果显示了燃料负荷密度的显著差异：大学办公室平均为 382 兆焦耳/平方米（标准差：297 兆焦耳/平方米），商业办公室平均为 1804 兆焦耳/平方米（标准差：1319 兆焦耳/平方米）。此外，它还提出了一种在线问卷调查方法，以克服现场访问的限制。此外，研究还发现，与大学办公室相比，商业办公室的燃料负荷密度较高，原因是纸张含量较高，占用密度较大。与以往的调查和设计规范相比，大学办公室的燃料负荷较低，而商业办公室的燃料负荷较高。值得注意的是，燃料负荷密度和塑料可燃物成分有逐年增加的趋势。此外，该研究还认为，在样本量较小的情况下，Gompertz 分布更适合燃料负荷密度数据的累积概率。总之，它为未来的火灾场景设计、消防法规修订和消防安全评估提供了一个宝贵的数据库，并探讨了未来与人工智能应用的合作。

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引用次数: 0

Bench-scale thermomechanical assessment of carbon fibre reinforced polymer C-channels 碳纤维增强聚合物 C 型通道的台架规模热力学评估

IF 3.4 3区工程技术 Q2 ENGINEERING, CIVIL

Fire Safety Journal

Pub Date : 2024-11-04 DOI: 10.1016/j.firesaf.2024.104285

Tim J. Aspinall , Emmajane L. Erskine , Kevin A. Denham , Derek C. Taylor , Rory M. Hadden

This study investigates the thermomechanical response of carbon fibre reinforced polymer (CFRP) C-channels using a bench-scale apparatus that combines mechanical loading and radiant thermal exposure. The study aims to assess the behaviour of pre-loaded CFRP C-channels, representative of aircraft sub-structures when subjected to fire conditions. Woven prepreg CFRP C-channels were tested under cantilever point load deflection while exposed to varying heat fluxes. Key aspects examined during the study include failure times, displacement, temperature distribution, and failure modes. The findings reveal that heated, pre-loaded C-channels experience distinct phases of physico-chemical decomposition and mechanical degradation. The mechanical degradation includes upward shear buckling of the horizontal flanges and vertical web, along with outward buckling of the vertical web towards the heat source. The study shows that thermal decomposition and mechanical degradation occur simultaneously, influenced by heat flux intensity. Higher heat fluxes accelerate decomposition and reduce load-bearing capacity, while lower fluxes slow degradation. Displacement data indicates that heat flux intensity significantly affects structural response. Temperature measurements show higher fluxes lead to elevated temperatures and steeper gradients, impacting failure times and modes. Increased temperatures correlate with shorter failure times, and variability in failure times decreases as heat flux rises. These insights are significant for understanding the thermomechanical response of C-channels in aircraft sub-structures. The knowledge obtained can contribute to developing more robust and safer aircraft designs, particularly for components exposed to fire conditions, enabling engineers to establish more precise safety margins for CFRP structures, potentially preventing catastrophic failures and thereby enhancing overall aircraft safety.

本研究使用一种结合了机械加载和辐射热暴露的台式设备，对碳纤维增强聚合物（CFRP）C 型槽的热机械响应进行了研究。该研究旨在评估预加载 CFRP C 型槽在火灾条件下的行为，它代表了飞机的子结构。在悬臂点荷载挠度下对编织预浸料 CFRP C 型槽进行了测试，同时暴露在不同的热通量下。研究的主要内容包括失效时间、位移、温度分布和失效模式。研究结果表明，加热的预加载 C 型槽经历了不同阶段的物理化学分解和机械退化。机械退化包括水平翼缘和垂直腹板的向上剪切屈曲，以及垂直腹板向热源的向外屈曲。研究表明，热分解和机械降解是同时发生的，受热流强度的影响。较高的热通量会加速分解并降低承载能力，而较低的热通量则会减缓退化。位移数据表明，热通量强度对结构响应有显著影响。温度测量结果表明，较高的热通量会导致温度升高和梯度增大，从而影响失效时间和失效模式。温度升高与失效时间缩短相关，而失效时间的变化则随着热通量的升高而减小。这些见解对于了解飞机子结构中 C 型通道的热机械响应具有重要意义。所获得的知识有助于开发更坚固、更安全的飞机设计，特别是暴露在火灾条件下的部件，使工程师能够为 CFRP 结构建立更精确的安全系数，从而有可能防止灾难性故障，进而提高飞机的整体安全性。

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引用次数: 0

How do passengers’ psychological conditions and behavioral conditions change in metro fire evacuation: An online questionnaire-based experiment 地铁火灾疏散中乘客的心理状况和行为状况如何变化：基于在线问卷的实验

IF 3.4 3区工程技术 Q2 ENGINEERING, CIVIL

Fire Safety Journal

Pub Date : 2024-11-02 DOI: 10.1016/j.firesaf.2024.104281

Jianyao Tu, Bozhezi Peng, Liwei Bai, Yi Zhang

引用次数: 0

Post-fire residual mechanical properties of Q460GJ steel under different pre-tensile stresses 不同预拉伸应力下 Q460GJ 钢的火烧后残余力学性能

IF 3.4 3区工程技术 Q2 ENGINEERING, CIVIL

Fire Safety Journal

Pub Date : 2024-10-30 DOI: 10.1016/j.firesaf.2024.104280

Siqi Li , Aibing Li , Weiyong Wang , Shan-Shan Huang

Previous studies on the post-fire mechanical properties of steel were conducted with unstressed state, without considering the influence of pre-stress which subjected to structures in reality. In this article, the post-fire residual mechanical properties of Q460GJ steel under different pre-tensile stresses were studied. The stress-strain curve, elastic modulus, yield strength, ultimate strength and fracture elongation of Q460GJ steel after different elevated temperatures heating are analyzed in detail. The experimental results are compared with that of Q460 steel and S460 steel in the existing literatures. At last, the predictive equations of post-fire mechanical properties of Q460GJ steel under different pre-tensile stresses are established. Q460GJ steel still maintains good ductility after elevated temperature heating, which increases the possibility of reuse of Q460GJ steel element after fire. The Q460GJ steel has better post-fire ductility than that of Q460 and S460 steels. The predictive equations for the post-fire residual mechanical properties for Q460GJ steel under different pre-tensile stresses were proposed. The variation coefficients of yield strength for Q460GJ steel under different pre-tensile stresses after 20 min different elevated temperatures heating were within 0.065. The findings should have a great significance to providing theoretical support for design of reusing or restoring steel building after fire.

以往关于钢材火烧后力学性能的研究都是在无应力状态下进行的，没有考虑实际结构所受预应力的影响。本文研究了 Q460GJ 钢在不同预拉伸应力下的火烧后残余力学性能。详细分析了 Q460GJ 钢在不同升温加热后的应力-应变曲线、弹性模量、屈服强度、极限强度和断裂伸长率。实验结果与现有文献中 Q460 钢和 S460 钢的实验结果进行了比较。最后，建立了 Q460GJ 钢在不同预拉伸应力下的火后力学性能预测方程。Q460GJ 钢在高温加热后仍能保持良好的延展性，这增加了 Q460GJ 钢构件在火灾后重新使用的可能性。与 Q460 和 S460 钢相比，Q460GJ 钢具有更好的火后延展性。提出了 Q460GJ 钢在不同预拉伸应力下的火后残余力学性能预测方程。Q460GJ 钢在不同预拉应力下，经过 20 分钟不同的高温加热后，屈服强度的变化系数在 0.065 以内。该研究结果对火灾后钢结构建筑的再利用或修复设计提供了理论支持，具有重要意义。

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引用次数: 0