Fire Safety Journal最新文献

{"title":"Downward opposed flame spread response to non-steady airflow","authors":"Alana Miska ,&nbsp;Pablo E. Pinto ,&nbsp;Xiuqi Xi ,&nbsp;Maria Thomsen ,&nbsp;James L. Urban","doi":"10.1016/j.firesaf.2025.104543","DOIUrl":"10.1016/j.firesaf.2025.104543","url":null,"abstract":"<div><div>PMMA is burned in a bench-scale wind tunnel under steady and oscillating airflows to characterize the downward flame spread response to non-steady airflow conditions. An opposed forced flow configuration is used with 0.5 and 1 mm thick black cast PMMA. The non-steady airflow oscillations for both PMMA thicknesses take the form of a transient sinusoidal profile with three amplitudes (0.1, 0.15 and 0.2 m/s), three frequencies (1/8, 1/16 and 1/32 Hz) and one baseline airflow (0.45 m/s). The time averaged and transient flame spread rate are measured using the change in pyrolysis front over time. The frequency response of the flame behavior, flame length and flame spread rate due to the impact of the non-steady airflow are investigated. A transient gas phase response is seen in all forced flow conditions. The smaller sample thickness displayed a clearer response in the transient flame spread to the non-steady airflow. This behavior is analyzed using physical timescales for solid-phase heating.</div></div>","PeriodicalId":50445,"journal":{"name":"Fire Safety Journal","volume":"158 ","pages":"Article 104543"},"PeriodicalIF":3.3,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145227618","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":"Numerical and experimental investigation of shaft-like compartment fires","authors":"Rabah Mehaddi ,&nbsp;Bouaza Lafdal ,&nbsp;Pascal Boulet","doi":"10.1016/j.firesaf.2025.104521","DOIUrl":"10.1016/j.firesaf.2025.104521","url":null,"abstract":"<div><div>The present study focuses on under-ventilated compartment fires, by analysing the results of an experimental and numerical study about fires issuing from heptane pools in a compartment with an open door. This compartment has an aspect ratio (height/width) of the order of 1.8 and a doorway with an aspect ratio up to 4, which is very different from conventional compartments. This type of geometry is therefore expected to yield new results. The key parameters in this case are the ventilation factor (based on the door height and its area) and the pool fire diameter. To analyse the combustion regimes, the fire Heat Release Rate (HRR) is split into two parts, namely, the HRR released inside and outside the compartment. To quantify these quantities, two experimental methods have been combined. The first one is based on temperature measurements inside the compartment. The second one combines measurements from radiative heat fluxes outside the compartment and images taken with visible cameras that provide the flame shape in order to evaluate the corresponding heat released rate. The experimental data have been compared to dedicated numerical simulations carried out with the CFD code Fire Dynamics Simulator. These comparisons have revealed that in a well-ventilated or moderately under-ventilated regime, integral quantities such as mean temperature, fire heat release rate inside and outside the room appear to be well predicted by the simulations. However, under the same conditions, the temperature profiles show differences that can be locally significant. This observation might be explained by a difficulty in correctly reproducing the flame dynamics and the air flow entering through the door. Furthermore, in the severely under-ventilated case, the temporal evolution of the average quantities (HRR and mean temperatures) are very poorly estimated by the simulations, as well as the local distributions. In this case the simulations predict that the combustion of all the combustible vapours occurs outside the door, which does not correspond to the physical observations. This phenomenon have been observed at <span><math><mrow><msup><mrow><mover><mrow><mi>Q</mi></mrow><mrow><mo>̇</mo></mrow></mover></mrow><mrow><mo>∗</mo></mrow></msup><mo>≈</mo><mn>1</mn><mo>.</mo><mn>6</mn></mrow></math></span>, where <span><math><msup><mrow><mover><mrow><mi>Q</mi></mrow><mrow><mo>̇</mo></mrow></mover></mrow><mrow><mo>∗</mo></mrow></msup></math></span> is the dimensionless heat released rate. Therefore, improvements of the CFD code are required to improve the simulations, probably also involving dedicated efforts on the ignition and extinction sub-models.</div></div>","PeriodicalId":50445,"journal":{"name":"Fire Safety Journal","volume":"158 ","pages":"Article 104521"},"PeriodicalIF":3.3,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145061294","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":"Impact of grassland fire dynamics on particulate emission factors","authors":"Alexander J. Josephson ,&nbsp;Johanna Aurell ,&nbsp;Susan A. Cohen ,&nbsp;Troy Walton ,&nbsp;Rodman R. Linn ,&nbsp;Brian K. Gullett","doi":"10.1016/j.firesaf.2025.104554","DOIUrl":"10.1016/j.firesaf.2025.104554","url":null,"abstract":"<div><div>Understanding particulate emission factors in grassland fires is critical for improving air quality assessments and refining emissions inventories. This study explores the dynamic and heterogeneous nature of fire processes and their influence on particulate emissions. Traditional emission factor inventories often rely on static values, overlooking the spatially and temporally variable dynamics of fire behavior. Through field experiments conducted at Konza Prairie Biological Station measuring emissions with uncrewed aerial vehicles, and computational modeling using HIGRAD/FIRETEC, this research highlights the dependency of emission production on localized fire dynamics, including ignition patterns, fuel properties, and atmospheric conditions. The results demonstrate a need for fire dynamic considerations to accurately capture emissions variability.</div></div>","PeriodicalId":50445,"journal":{"name":"Fire Safety Journal","volume":"158 ","pages":"Article 104554"},"PeriodicalIF":3.3,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145333465","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":"Methodology for detecting firebrand generation and the analysis of influential variables in quantification","authors":"Fernando Ebensperger,&nbsp;Raphael Ogabi,&nbsp;Albert Simeoni","doi":"10.1016/j.firesaf.2025.104549","DOIUrl":"10.1016/j.firesaf.2025.104549","url":null,"abstract":"<div><div>Firebrands play a dominant role in wildland fire propagation, especially in spotting, where embers are carried away from the main fire to ignite new areas. Three mechanisms govern their dynamics: generation, transport, and landing. While transport and landing have received more attention in the literature, generation remains poorly understood due to challenges in real-time quantification and detection. This shortcoming undermines fire spread models that require accurate estimation of particle properties and numbers. To address this, a UNet-based convolutional neural network (CNN) image processing method was developed to detect and segment firebrands from images and video. The model demonstrated over 80 % accuracy with limited training data, suggesting potential for field use with low-cost, heterogeneous imaging systems. Experiments were conducted in large wind tunnel (1.5m <span><math><mo>×</mo></math></span> 2.1m <span><math><mo>×</mo></math></span> 6 m) at uniform wind speeds up to 6.2 m/s and test velocities between 0.5 to 1.5 m/s. Douglas Fir samples were burned, and mass loss was measured using balances. Fuel positioning affected firebrand production: free samples (1.5 kg) exhibited multiple intense burning stages due to deformation, whereas restrained samples (0.76 kg) burned more uniformly. The proposed CNN approach offers a promising tool for supporting firebrand detection.</div></div>","PeriodicalId":50445,"journal":{"name":"Fire Safety Journal","volume":"158 ","pages":"Article 104549"},"PeriodicalIF":3.3,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145333469","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":"Stochastic modeling of the flight of embers ejected from an ember dragon","authors":"Nigel B. Kaye ,&nbsp;Khalid Moinuddin ,&nbsp;Rahul Wadhwani","doi":"10.1016/j.firesaf.2025.104523","DOIUrl":"10.1016/j.firesaf.2025.104523","url":null,"abstract":"<div><div>Spot-fire generation from embers blown ahead of a wildfire front is one of the leading causes of home destruction in wildland-urban interface (WUI) fires. It is, therefore, important to be able to model wind-driven ember flight accurately. This study presents the application of a stochastic debris flight model to this problem. The model embeds the uncertainty in flight conditions into the model by randomly perturbing the flight parameters (drag and lift forces) at each numerical integration time step. The stochastic flight model replicates the results of a series of ember flight tests run using the Victoria University ember dragon for both cubic and cylindrical model embers. Results show that the stochastic model produces very good predictions of the mean landing location of the embers tested. The model also provides reasonable estimates of the standard deviation and skewness of the landing location distribution in the direction of the initial launch for the cubic embers. The agreement with higher moment statistics is poorer for the cylindrical embers, though there is qualitative consistency between the experimental and model spatial distributions.</div></div>","PeriodicalId":50445,"journal":{"name":"Fire Safety Journal","volume":"158 ","pages":"Article 104523"},"PeriodicalIF":3.3,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145050693","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":"Data-driven and explainable AI models for evaluating bond strength in reinforced concrete at elevated temperatures","authors":"Rwayda Kh.S. Al-Hamd ,&nbsp;Asad S. Albostami ,&nbsp;Holly Warren","doi":"10.1016/j.firesaf.2025.104514","DOIUrl":"10.1016/j.firesaf.2025.104514","url":null,"abstract":"<div><div>The bond between steel and concrete in reinforced concrete (RC) and fibre-reinforced concrete (FRC) structures is a multifaceted and intricate phenomenon. It refers to the adhesion and mechanical interlock between the steel reinforcement bars and the surrounding concrete matrix. The bond becomes more complex at elevated temperatures; however, having an accurate estimate is a crucial factor in design. Therefore, this paper employs advanced machine learning (ML) techniques to predict bond strength (<em>T_b</em>) at both ambient and elevated temperatures from a 394-point experimental database, which includes additional variables such as fibre content, geometric ratios, and thermal parameter conditions. Seven models were built and assessed, including Linear Regression (LR), Gradient Boosting (GB), Extreme Gradient Boosting (XGBoost), Artificial Neural Network (ANN), <em>k</em>-nearest Neighbours (KNN), Decision Tree (DT), and Deep Learning (DLearning) Regressors. The GB, XGBoost, and DT models offered the best prediction results with R² above 0.95 for the testing datasets, lowest error metrics (mean absolute error (MAE) between 0.8 and 1.1 MPa), and highest reliability (a30%-index ≥ 90%), all outperforming those reported in earlier literature. According to SHapley Additive exPlanations (SHAP) analysis, the length-to-diameter ratio (<span><math><mrow><mfrac><mi>l</mi><mi>d</mi></mfrac></mrow></math></span>) and failure surface temperature (<span><math><mrow><mi>T</mi></mrow></math></span>) dominated as the predictors, followed by concrete compressive strength (<span><math><mrow><msub><mi>f</mi><mi>c</mi></msub></mrow></math></span>), and cover-to-diameter ratio (<span><math><mrow><mfrac><mi>c</mi><mi>d</mi></mfrac></mrow></math></span>), which is according to the existing mechanics of bond and thermal degradation. This study presents resolutions regarding the promise of data-driven models to accurately, reliably, and interpretably predict bond strength in post-fire conditions, which is of great merit in terms of resilient design practice. Future work may investigate hybrid ML–mechanistic frameworks and the integration of full-scale fire testing to further enhance engineering applicability.</div></div>","PeriodicalId":50445,"journal":{"name":"Fire Safety Journal","volume":"158 ","pages":"Article 104514"},"PeriodicalIF":3.3,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145050694","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":"Conditions for onset and sustained char oxidation","authors":"Laura Schmidt,&nbsp;Rory M. Hadden","doi":"10.1016/j.firesaf.2025.104539","DOIUrl":"10.1016/j.firesaf.2025.104539","url":null,"abstract":"<div><div>Smouldering combustion of timber presents a significant fire safety concern, particularly in scenarios where heat retention enables sustained char oxidation. This study isolates char oxidation from other smouldering processes to investigate its onset and sustained reaction under close-to-critical incident heat fluxes. Experiments using pre-pyrolysed char samples provided direct measurements of CO and CO₂ generation, mass loss, and temperature evolution during char oxidation. The onset of char oxidation was characterised by a rapid increase in CO generation rate, occurring consistently at an external heat flux of 10 kW/m². Among the methods tested, CO mass flow rates proved to be the most reliable indicator of char oxidation onset, offering greater precision than traditional mass loss measurements or temperature data in determining the char oxidation onset time. Once initiated, oxidation led to sustained heat release, with in-depth temperatures exceeding 400 °C, peak heat release rates of ∼29 kW/m² and a mean effective heat of combustion of ∼30.3 kJ/g, close to the char's gross heat of combustion, at 10 kW/m². These findings improve the understanding of char oxidation kinetics and support the development of predictive models for smouldering in engineered timber, informing fire hazard assessment and mitigation strategies.</div></div>","PeriodicalId":50445,"journal":{"name":"Fire Safety Journal","volume":"158 ","pages":"Article 104539"},"PeriodicalIF":3.3,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145227619","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 study of fire propagation along a vertical wall in a lab scale setup","authors":"F. Di Giorgio,&nbsp;C. Galizzi,&nbsp;M. Kühni","doi":"10.1016/j.firesaf.2025.104540","DOIUrl":"10.1016/j.firesaf.2025.104540","url":null,"abstract":"<div><div>A characterization study was conducted on a novel experimental setup designed to investigate the spread of façade fires. This setup consists of a wall divided into an effusion zone, where methane injection simulates the pyrolysis process, and a large inert zone where the flame propagates. Various flow rates were applied to the effusion module and analyzed through direct visualizations, CH* and OH* chemiluminescence imaging, as well as temperature and heat flux. The results highlight and confirm the well-established influence of fuel injection rates on flame behavior and propagation. This standardized configuration serves as a benchmark for comparisons with more complex scenarios involving different arrangements of effusion and inert zones. Moreover, the data generated in this study provide a valuable basis for evaluating the reliability of fire engineering models and codes.</div></div>","PeriodicalId":50445,"journal":{"name":"Fire Safety Journal","volume":"158 ","pages":"Article 104540"},"PeriodicalIF":3.3,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145159746","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":"Simple prediction equation for ceiling jet flow arrival time in space without vertical wall soffit","authors":"Hyewon Kim ,&nbsp;Jun-ichi Yamaguchi ,&nbsp;Hyun-woo Park ,&nbsp;Yoshifumi Ohmiya","doi":"10.1016/j.firesaf.2025.104520","DOIUrl":"10.1016/j.firesaf.2025.104520","url":null,"abstract":"<div><div>Currently, in two-zone models, smoke flow is calculated based on the assumption that the fire plume, which develops directly above the fire source, depends solely on the amount of entrained surrounding air. However, in large flat spaces, which have been growing larger in recent years, the horizontal travel distance of ceiling jet flow is long, and it is possible that the amount of smoke due to entrainment of air during the horizontal spread process is underestimated. In this study, we performed experiments that reproduced an unconfined ceiling without a vertical wall soffit and determined the amount of entrainment in the ceiling jet flow by analyzing the gas concentration of ceiling jet flow at various flow distances. Next, we formulated the ceiling jet flow rate by expressing this in terms of dimensionless flow rate and dimensionless flow distance. Furthermore, we derived a simple prediction equation for ceiling jet flow arrival time based on the model equation. Finally, we validated the proposed equation and range of applicability through comparison with the results of several experiments.</div></div>","PeriodicalId":50445,"journal":{"name":"Fire Safety Journal","volume":"158 ","pages":"Article 104520"},"PeriodicalIF":3.3,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145050695","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":"Toxicant production in under-ventilated compartment fires assessed by laser absorption spectroscopy","authors":"Rayna Vreeland ,&nbsp;Kyle L. Fetter ,&nbsp;Nicolas S.B. Jaeger ,&nbsp;Yi Yan ,&nbsp;Xiuqi Xi ,&nbsp;James L. Urban ,&nbsp;Daniel I. Pineda ,&nbsp;R. Mitchell Spearrin","doi":"10.1016/j.firesaf.2025.104534","DOIUrl":"10.1016/j.firesaf.2025.104534","url":null,"abstract":"<div><div>The production of incomplete combustion products from the burning of wood, medium density fiberboard (MDF), and nylon in an under-ventilated compartment fire was investigated using a reduced-scale compartment. Species measurements of carbon monoxide (CO) and carbon dioxide (CO₂) were performed using Fourier Transform Infrared Spectroscopy (FTIR) and methane (CH₄), hydrogen cyanide (HCN), benzene (C₆H₆), ethylene (C₂H₄) and acetylene (C₂H₂) were measured with Laser Absorption Spectroscopy (LAS) with three different interband cascade lasers. The fuels were burned in three different crib configurations; only wood, only MDF, and a mixture of wood and nylon, to examine the production of different toxicants. During the experiments, measurements were collected of CO, CO₂, CH₄, HCN, C₂H₂, and C₆H₆ species from the gas exiting the compartment, gas temperature from inside the compartment, and the flow into and out of the compartment. Consistent with under-ventilated combustion, the temperature inside the compartment typically exceeded 600 °C. CO was measured during all experiments and was two orders of magnitude less than the measured CO₂ concentration. Significant amounts of unburned hydrocarbons were measured during all of the experiments, while HCN was only detected during the wood-nylon tests. Higher toxicant yields were measured for wood-nylon compared to pure wood and MDF.</div></div>","PeriodicalId":50445,"journal":{"name":"Fire Safety Journal","volume":"158 ","pages":"Article 104534"},"PeriodicalIF":3.3,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145363211","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}