Fire Safety Journal最新文献

{"title":"Effect of the wood species on the fire behavior in vertical orientation","authors":"Lucas Terrei ,&nbsp;Hassan Flity ,&nbsp;Oualid Ikhou ,&nbsp;Gaspard Trohel ,&nbsp;José Luis Torero ,&nbsp;Zoubir Acem ,&nbsp;Gilles Parent","doi":"10.1016/j.firesaf.2024.104234","DOIUrl":"10.1016/j.firesaf.2024.104234","url":null,"abstract":"<div><p>The objective of this study was to investigate the parameters controlling auto-ignition, degradation and auto-extinction of wood. For this purpose an extensive set of experiments was conducted varying extrinsic parameters such as external heat-flux but also the type of wood. Varying the wood species allowed to explore the role of thermal properties and wood composition. Seven wood samples were tested, some light and some heavy, both hardwood and softwood. The experimental setup was based on a double-cone calorimeter, which allowed to accurately change the imposed heat flux at a predefined moment. More than 600 tests were carried out in a vertical orientation, allowing a statistical analysis. For each test, mass loss, surface temperature and in-depth temperature of the samples were measured using a precision scale, an infrared camera and thin wire thermocouples embedded using a special machining, respectively. The auto-ignition study showed that the time to auto-ignition increases linearly with density. Despite a wide range of these times to ignition, the surface temperatures at ignition were in the same order of magnitude for all species considered: between 450 and 700 °C for auto-ignition before 2 min and between 700 and 800 °C for auto-ignition after 2 min. The onset of char oxidation was observed at low heat fluxes. It occurs at different times depending on the wood species, but at similar surface temperatures, between 380 and 400 °C. The sliding double heating cone made it possible to identify the criteria for auto-extinction: the heat flux for auto-extinction can vary from 40 to 55 kW.m⁻² depending on the wood species, and a linear correlation was found between the mass loss rate at extinction and the initial density of each sample studied. The study highlights the dominant role of density for auto-ignition and auto-extinction.</p></div>","PeriodicalId":50445,"journal":{"name":"Fire Safety Journal","volume":null,"pages":null},"PeriodicalIF":3.4,"publicationDate":"2024-07-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0379711224001474/pdfft?md5=d1d9101ed3360370ed47abf860f25a5a&pid=1-s2.0-S0379711224001474-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141935484","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Experimental and numerical study on data-driven prediction for wildfire spread incorporating adaptive observation error adjustment","authors":"Zheng Wang ,&nbsp;Xingdong Li ,&nbsp;Mengxia Zha ,&nbsp;Jie Ji","doi":"10.1016/j.firesaf.2024.104230","DOIUrl":"10.1016/j.firesaf.2024.104230","url":null,"abstract":"<div><p>In recent wildfire prediction research, data assimilation (DA) methods like Ensemble Kalman filtering have gained traction for integrating observation data to enhance prediction accuracy. Most previous studies trusted that the observation data were accurate, and set a small observation error, which causes unreliable predicted results for scenarios with large observation error. To tackle this, our study introduced a method that iteratively adjusted the potential range of observation errors by comparing observation and simulation data over time. We conducted a 30-m experiment and kilometer-scale numerical simulations. Unlike prior research, we adopted larger error ranges (the similarity index with true data ranges from 0.6 to 1) for both real and synthetic observation data. In the experiment, to increase the complexity of fire spread, a heterogeneous fuel arrangement was employed. Irregular flame fronts appeared due to incomplete combustion and were difficult to replicate in simulations. Better accuracy was achieved using real observation data to revise predictions. Furthermore, to improve the applicability of the algorithm, numerical simulations were designed to consider observation error changing over time or not. The Root Mean Square Errors for the fire front prediction using the proposed method remained lower than that of the traditional DA approach.</p></div>","PeriodicalId":50445,"journal":{"name":"Fire Safety Journal","volume":null,"pages":null},"PeriodicalIF":3.4,"publicationDate":"2024-07-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141935486","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Analysis of visual and acoustic measures for self-evacuations in road tunnels using virtual reality","authors":"Jo Skjermo ,&nbsp;Claudia Moscoso ,&nbsp;Daniel Nilsson ,&nbsp;Håkan Frantzich ,&nbsp;Åsa S. Hoem ,&nbsp;Petter Arnesen ,&nbsp;Gunnar D. Jenssen","doi":"10.1016/j.firesaf.2024.104224","DOIUrl":"10.1016/j.firesaf.2024.104224","url":null,"abstract":"<div><p>Emergency fire situations in tunnels can be especially dangerous when occurring in long underground or subsea tunnels, particularly when evacuation on foot is the only alternative. This paper presents the results from a study comparing different visual and acoustic measures to facilitate efficient and safe emergency evacuation and their effect on people's self-rescue behaviour in response to a tunnel fire. Eighty-one participants evaluated seven different scenarios in virtual reality with or without visual and acoustic supporting measures (i.e. signs, lights, acoustic beacons) to find their way to emergency doors. Objective behavioural data, such as orientation, and walking speed, were collected. The results suggest that the distance between the emergency doors increases uncertainty and affects the time to self-rescue significantly, with four times longer times for 500 m than 250 m between doors. Additionally, the use of continuous guiding lights positively supported orientation and walking speed, with 97 % of the participants finding their way and showing a reduction of time to reach the emergency door of 10–20 s. The study underscores the importance in the proper visual and acoustic evacuation measures for the wayfinding of emergency exits, improving self-rescue of people.</p></div>","PeriodicalId":50445,"journal":{"name":"Fire Safety Journal","volume":null,"pages":null},"PeriodicalIF":3.4,"publicationDate":"2024-07-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0379711224001371/pdfft?md5=f9af78c822fe9a564b2f21af7e1ce1c9&pid=1-s2.0-S0379711224001371-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141839818","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Suppression effects of different extinguishing agents on vent gases fires from lithium-ion batteries after thermal runaway: A comprehensive experimental and numerical study","authors":"Shilin Wang ,&nbsp;Xu Gong ,&nbsp;Ruihua Shao ,&nbsp;Lejun Xu ,&nbsp;Yitong Li ,&nbsp;Fenfen He ,&nbsp;Qinzheng Wang ,&nbsp;Xi Wang ,&nbsp;Huaibin Wang ,&nbsp;Chengshan Xu ,&nbsp;Xuning Feng","doi":"10.1016/j.firesaf.2024.104227","DOIUrl":"10.1016/j.firesaf.2024.104227","url":null,"abstract":"<div><p>During the thermal runaway process of lithium-ion batteries, the release of vaporized electrolyte and combustible gases can lead to the formation of a jet flame, posing a significant fire or explosion risk. In order to deal with the threat of lithium-ion battery vent gas fires to the safety of energy storage power stations, it's crucial to identify effective fire extinguishing agents for lithium-ion battery systems. This study employs a combination of experimental and numerical simulation methods to assess the suppression capabilities of CO₂, N₂, and HFC-227ea on vent gas/air premixed flames originating from lithium-ion batteries with various cathode materials. Laminar flame speed of vent gas/air/extinguishing agent premixed flames at specific equivalence ratios were measured using a Bunsen burner device under ambient temperature and atmospheric pressure conditions. Additionally, numerical calculations of laminar flame speed and adiabatic flame temperature were conducted using CHEMKIN-Pro, accompanied by an analysis of the chemical inhibition mechanism of HFC-227ea. The findings reveal that although HFC-227ea may slightly elevate the adiabatic flame temperature at lower equivalence ratios, its overall fire extinguishing efficacy surpasses that of CO₂ and N₂. These results offer valuable insights for selecting appropriate fire extinguishing agents for energy storage power stations, thereby enhancing the safety standards of energy storage systems.</p></div>","PeriodicalId":50445,"journal":{"name":"Fire Safety Journal","volume":null,"pages":null},"PeriodicalIF":3.4,"publicationDate":"2024-07-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141846164","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Full-scale hybrid fire test in real-time with multiple degree of freedom","authors":"Silvio Renard ,&nbsp;Jean-Christophe Mindeguia ,&nbsp;Fabienne Robert ,&nbsp;Stéphane Morel ,&nbsp;Jean-Marc Franssen","doi":"10.1016/j.firesaf.2024.104233","DOIUrl":"10.1016/j.firesaf.2024.104233","url":null,"abstract":"<div><p>To experimentally assess the fire resistance of civil structures, testing whole structures is very costly but the standard tests on individual structural elements can sometimes be too simplistic, regarding their boundary conditions. Hybrid fire testing offers a promising solution to these limitations, but performing such tests is technically challenging and few full-scale tests have been conducted. Current approaches rely on high-performance sensors and actuator systems, as well as assumptions about the stiffness of the tested element. This paper presents the detailed methodology and results of a full-scale, real-time test with 3 degrees of freedom on a concrete beam. The use of an adaptive controller allowed for maintaining stability and achieving reasonable precision despite the use of relatively low-precision sensors, regular hydraulic actuators, and no assumptions about the tested element’s stiffness. The comparison with the same element tested using a standard fire resistance test demonstrates the usefulness of this technique in achieving a more accurate representation of the performance of the tested element in realistic conditions.</p></div>","PeriodicalId":50445,"journal":{"name":"Fire Safety Journal","volume":null,"pages":null},"PeriodicalIF":3.4,"publicationDate":"2024-07-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141842747","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Experimental observation of crack formation on surface of charring timber","authors":"Aleksi Rinta-Paavola ,&nbsp;Andrea Ferrantelli ,&nbsp;Simo Hostikka","doi":"10.1016/j.firesaf.2024.104231","DOIUrl":"10.1016/j.firesaf.2024.104231","url":null,"abstract":"<div><p>Crack formation on the charring surface of burning wood is an important factor increasing the burning rate by offering a passage for heat and oxygen, but it remains a poorly understood process. This work considers crack formation on pyrolyzing Norway spruce, Scots pine and birch timbers. Timber specimens of different sizes were tested under various radiative heat fluxes in nitrogen atmosphere. The cracking process was followed with an infrared camera mounted above the specimen. The obtained recordings were used to determine the formation times and lengths of cracks and to estimate the validity of an existing thermomechanical model for crack formation. The results show that the crack formation time has no significant dependence on the specimen geometry. Further, the inverse of the square root of crack formation time follows grows linearly with external heat flux, which is a similar dependence as with time for ignition, according to the thermal model of ignition. The analytical model predictions were of correct order of magnitude, but not consistently accurate at all experimental conditions. This could be accounted for the simplifying assumptions within the analytical model, and therefore creating a more detailed three-dimensional numerical model for crack formation is suggested as future research.</p></div>","PeriodicalId":50445,"journal":{"name":"Fire Safety Journal","volume":null,"pages":null},"PeriodicalIF":3.4,"publicationDate":"2024-07-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0379711224001449/pdfft?md5=b8dd48ff6fcac2b7424e4afc84bb947c&pid=1-s2.0-S0379711224001449-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141842308","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Empirical study on the influence of initial relative humidity on wood crib fire behavior in compartment under varied natural ventilation conditions","authors":"Seyed Ahmad Kebriyaee,&nbsp;Mohammad Moghiman,&nbsp;Hamid Niazmand","doi":"10.1016/j.firesaf.2024.104229","DOIUrl":"10.1016/j.firesaf.2024.104229","url":null,"abstract":"<div><p>This empirical study investigates the influence of initial relative humidity (RH) variations (35 % and 95 %) on key fire behavior parameters, specifically focusing on the fully developed stage, occurrences of flashover, and the temperature of the upper gas layer. Wooden cribs weighing 10 kg–40 kg are used as fuel in a compartment with three openings to establish different natural ventilation conditions. The experimental findings reveal that increasing the initial RH within the chamber leads to a delay in the onset of the fire growth phase. Furthermore, it induces two noticeable effects on the fully developed fire stage: a reduction in its duration by up to 50 % and a delay in its initiation by at least 30 s. While heightened initial RH does not prevent flashover, it effectively postpones its occurrence by a minimum of 40 s. Experiments with maximum fuel loads demonstrate negligible effects of increased RH on the maximum temperature, even under varying ventilation conditions. Conversely, lower fuel loads exhibit a significant decline in temperature with rising humidity, notably from 626 °C to 474 °C. The quantitative and qualitative insights derived from this study have considerable potential to inform the development of more effective fire suppression strategies in enclosed compartments.</p></div>","PeriodicalId":50445,"journal":{"name":"Fire Safety Journal","volume":null,"pages":null},"PeriodicalIF":3.4,"publicationDate":"2024-07-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141960623","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Full-field temperature prediction in tunnel fires using limited monitored ceiling flow temperature data with transformer-based deep learning models","authors":"Xin Guo ,&nbsp;Dong Yang ,&nbsp;Li Jiang ,&nbsp;Tao Du ,&nbsp;Shan Lyu","doi":"10.1016/j.firesaf.2024.104232","DOIUrl":"10.1016/j.firesaf.2024.104232","url":null,"abstract":"<div><p>In practical tunnel scenarios, full-field coverage of sensors is impractical and costly. During a tunnel fire, the available information is constrained and localized, making the prediction of full-field smoke temperature distribution becoming a noteworthy challenge. This study proposes a transformer-based deep learning model to predict full-field smoke temperature distributions during fire incidents in real-time using limited temporal data from the sensors installed in localized regions below the ceiling, considering heat release rate of the fire source is unknown. The results indicate that proposed approach can predict the longitudinal temperature distribution throughout the tunnel with a length of 750 m by leveraging temperature data from limited sensors within a monitoring length of 210 m. It can further predict the vertical temperature profiles, and eventually estimate the full-field temperature distribution within the tunnel. The transformer model achieved R² of 0.95 and 0.87 for longitudinal and vertical temperature distribution predictions, respectively. Under the influence of the self-attention mechanism, the transformer model has an advantage over the long short-term memory model in capturing global information, enhancing the accuracy of longitudinal temperature distribution predictions by 18.8 %. This study significantly contributes to effective emergency response and rescue strategies during tunnel fire incidents.</p></div>","PeriodicalId":50445,"journal":{"name":"Fire Safety Journal","volume":null,"pages":null},"PeriodicalIF":3.4,"publicationDate":"2024-07-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141960622","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Experimental investigation on the fire performance of wood bio-concrete using Cone Calorimeter","authors":"Amanda L.D. Aguiar ,&nbsp;Bruno M.C. Gomes ,&nbsp;Monique A.F.R. Nascimento ,&nbsp;Alexandre Landesmann ,&nbsp;Romildo D. Toledo Filho","doi":"10.1016/j.firesaf.2024.104225","DOIUrl":"10.1016/j.firesaf.2024.104225","url":null,"abstract":"<div><p>Nowadays, wood bio-concrete (WBC) can be seen as an alternative to reduce environmental impacts of the construction industry. The behavior of this material under fire conditions, however, is still poorly understood. In this sense, this work aims to investigate the behavior of wood bio-concrete under fire conditions. In this study, the wood shavings content varied from 40 to 90 %. A Mass Loss Cone Calorimeter with an incident heat flux of 50 kW/m² was used to analyze the combustion and reaction to fire of WBCs. Then, properties such as heat release rate, total heat released, total mass loss, mass loss rate, effective heat of combustion, time to ignition and temperature of ignition were evaluated. Thermogravimetric analysis (TG) and scanning electron microscopy (SEM) were used to better explain the results from the Cone Calorimeter tests. The results showed that the cementitious matrix promoted the protection of the wood and no ignition was observed for the materials studied, excepted when 90 % of shavings were used. The lower the density of the bio-concrete, the higher the values of combustion properties. This study confirmed that, under high heat flux conditions, most of the WBCs did not exhibit characteristics that promote ignition or flame propagation.</p></div>","PeriodicalId":50445,"journal":{"name":"Fire Safety Journal","volume":null,"pages":null},"PeriodicalIF":3.4,"publicationDate":"2024-07-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141728983","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Smoldering ignition and transition to flaming in wooden mulch beds exposed to firebrands under wind","authors":"Shaorun Lin ,&nbsp;Chengze Li ,&nbsp;Mackenzie Conkling ,&nbsp;Xinyan Huang ,&nbsp;Stephen L. Quarles ,&nbsp;Michael J. Gollner","doi":"10.1016/j.firesaf.2024.104226","DOIUrl":"10.1016/j.firesaf.2024.104226","url":null,"abstract":"<div><p>Spotting ignition by firebrands is a significant fire spread pathway at the wildland-urban interface (WUI), where mulch products are commonly used as landscaping materials. Mulch is typically organic in nature, thus it may be easily ignited into a smoldering mode by firebrands and subsequently transition to flaming, leading to direct flame contact and radiant heat exposure to siding materials of adjacent structures. This work quantified the thresholds of smoldering ignition of four common types of commercially available mulch (black mulch (BM), forest floor (FF), redwood (RW), and fir bark (FB)) exposed to heating by smoldering firebrand piles, and their propensity for smoldering-to-flaming transition under external winds (up to 1.4 m/s). We found that there was a minimum mass of firebrand pile to achieve smoldering ignition of mulch (e.g., ∼0.1 g for FF). Beyond this minimum mass, the required wind speed to trigger smoldering ignition generally decreased as the mass of the firebrand pile increased, agreeing well with theoretical analysis. After smoldering ignition, smoldering-to-flaming transition could be observed when the wind speed exceeded a critical value (e.g., ∼1 m/s for FF), which was not affected by the initial spotting process. To achieve smoldering-to-flaming transition, the glowing mulch had to reach a critical temperature of around 850 °C. Mulch samples with larger particle sizes were more likely to smolder and transition to flaming, due to increased oxygen supply through larger inter-particle pores and channels and better firebrand accumulation due to a more crevice-like geometry on the fuel surface. This work advances the fundamental understanding of the ignition and burning behavior of landscaping mulches, and thus contributes to the prevention of extreme WUI fire events.</p></div>","PeriodicalId":50445,"journal":{"name":"Fire Safety Journal","volume":null,"pages":null},"PeriodicalIF":3.4,"publicationDate":"2024-07-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0379711224001395/pdfft?md5=cd0426b57b88d06163a740938140e956&pid=1-s2.0-S0379711224001395-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141732142","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}