Pub Date : 2026-06-01Epub Date: 2026-01-22DOI: 10.1016/j.firesaf.2026.104647
Chuanjia Wu , Yuhan Jiang , Yutao Li , Feng Zhu , Shuangfeng Wang
Near-limit steady laminar diffusion flames over a solid surface was investigated under various near-limit conditions. Detailed measurements of gas-phase temperature, solid-phase temperature, surface temperature, and mass loss rate were conducted. The heat flux at the fuel surface and the mass transfer number (B) were calculated to assess the flammability of the fuel. The results indicate that as the ambient pressure decreases and the Limit Oxygen Concentration (LOC) increases, the flame temperature, flame radiation, and solid-phase conductive heat flux all increase, while the gas convective heat flux decreases. Notably, the surface temperature and radiant heat flux remain unaffected by changes in environmental conditions. Meanwhile, the heat loss increases with the LOC. The critical B number exhibits a non-monotonic trend with the increase of the oxygen concentration: it initially decreases, reaches a minimum, and then increases. Both theoretical calculations and experimental measurements show this same trend. However, the theoretical calculation B number is affected by the fraction of flame radiation, which leads to the different values between them.
{"title":"B number for near-limit steady laminar diffusion flames over a solid surface","authors":"Chuanjia Wu , Yuhan Jiang , Yutao Li , Feng Zhu , Shuangfeng Wang","doi":"10.1016/j.firesaf.2026.104647","DOIUrl":"10.1016/j.firesaf.2026.104647","url":null,"abstract":"<div><div>Near-limit steady laminar diffusion flames over a solid surface was investigated under various near-limit conditions. Detailed measurements of gas-phase temperature, solid-phase temperature, surface temperature, and mass loss rate were conducted. The heat flux at the fuel surface and the mass transfer number (<em>B</em>) were calculated to assess the flammability of the fuel. The results indicate that as the ambient pressure decreases and the Limit Oxygen Concentration (LOC) increases, the flame temperature, flame radiation, and solid-phase conductive heat flux all increase, while the gas convective heat flux decreases. Notably, the surface temperature and radiant heat flux remain unaffected by changes in environmental conditions. Meanwhile, the heat loss increases with the LOC. The critical <em>B</em> number exhibits a non-monotonic trend with the increase of the oxygen concentration: it initially decreases, reaches a minimum, and then increases. Both theoretical calculations and experimental measurements show this same trend. However, the theoretical calculation <em>B</em> number is affected by the fraction of flame radiation, which leads to the different values between them.</div></div>","PeriodicalId":50445,"journal":{"name":"Fire Safety Journal","volume":"161 ","pages":"Article 104647"},"PeriodicalIF":3.3,"publicationDate":"2026-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146038631","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}
Pub Date : 2026-06-01Epub Date: 2026-02-05DOI: 10.1016/j.firesaf.2026.104655
Su-Hoon Park , Dong Yoon Lee , Seungmin Heo , Jin-Han Park , Sung Man Son , Myeong Seop Jung , Woo Rim Youn , Se-Jin Yook
With increasing air pollution and energy shortages, rechargeable batteries have become a key focus as alternatives to petroleum energy. However, lithium-ion batteries may experience thermal runaway caused by mechanical damage or internal electrochemical defects, resulting in gas venting, material ejecta, fire, and in some cases deflagration of the released gases. This study assembled a battery module using 16 medium-to large-sized cells having a capacity of 181.2 Ah. To mitigate heat transfer within the module, inter-cell thermal barrier pads (TBPs) were created by combining mica with silicone, polyurethane foam, or steel, resulting in four different configurations applied to the module. Pad thicknesses of 1.35, 1.60, 1.85, and 2.0 mm were tested, but no significant correlation between total pad thickness and thermal runaway delay was observed. However, increasing the thickness of mica, which has the minimal thermal conductivity (0.4 W/m·K) among the materials tested, extended the delay time. Based on these results, TBPs having at least 0.6 mm in thickness and below 0.4 W/m·K in thermal conductivity are recommended for improving safety by mitigating heat propagation between cells. These findings are expected to contribute to the stability of rechargeable battery systems, especially in applications like electric vehicles and energy storage.
{"title":"Thermal runaway delay characteristics in high-capacity lithium-ion battery modules incorporating various inter-cell thermal barrier pad types","authors":"Su-Hoon Park , Dong Yoon Lee , Seungmin Heo , Jin-Han Park , Sung Man Son , Myeong Seop Jung , Woo Rim Youn , Se-Jin Yook","doi":"10.1016/j.firesaf.2026.104655","DOIUrl":"10.1016/j.firesaf.2026.104655","url":null,"abstract":"<div><div>With increasing air pollution and energy shortages, rechargeable batteries have become a key focus as alternatives to petroleum energy. However, lithium-ion batteries may experience thermal runaway caused by mechanical damage or internal electrochemical defects, resulting in gas venting, material ejecta, fire, and in some cases deflagration of the released gases. This study assembled a battery module using 16 medium-to large-sized cells having a capacity of 181.2 Ah. To mitigate heat transfer within the module, inter-cell thermal barrier pads (TBPs) were created by combining mica with silicone, polyurethane foam, or steel, resulting in four different configurations applied to the module. Pad thicknesses of 1.35, 1.60, 1.85, and 2.0 mm were tested, but no significant correlation between total pad thickness and thermal runaway delay was observed. However, increasing the thickness of mica, which has the minimal thermal conductivity (0.4 W/m·K) among the materials tested, extended the delay time. Based on these results, TBPs having at least 0.6 mm in thickness and below 0.4 W/m·K in thermal conductivity are recommended for improving safety by mitigating heat propagation between cells. These findings are expected to contribute to the stability of rechargeable battery systems, especially in applications like electric vehicles and energy storage.</div></div>","PeriodicalId":50445,"journal":{"name":"Fire Safety Journal","volume":"161 ","pages":"Article 104655"},"PeriodicalIF":3.3,"publicationDate":"2026-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146189452","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}
Pub Date : 2026-06-01Epub Date: 2025-12-23DOI: 10.1016/j.firesaf.2025.104626
Mahadev Rokade, Tim Stratford, Dave Rush
A dataset of 165 fire tests on rectangular concrete columns, spanning five decades, was compiled to evaluate six design methods from five international codes (Eurocode Methods A and B (ECA, ECB), Australian (AS 3600), Chinese (DBJ/T), American (ACI), and Indian (NBC)). A meta-analysis assessed their predictive reliability using historical and recent results. ECA and AS 3600 gave the most consistent and conservative predictions, with ECA performing best overall. For fire resistance ratings (FRR) < 240 min, about 70 % of ECA (2019) predictions were within ±20 % of test outcomes, though accuracy declined at longer durations. AS 3600 produced similar results due to its related formulation. ECB changed notably: 2019 method was unreliable for FRR >140 min, whereas the 2023 version aligned better with recent tests and reduced excessive conservatism. DBJ/T performed adequately on older specimens but overestimated newer ones, while ACI and NBC showed high variability and frequent unconservative predictions. Assessment of the robustness of the ECA (2023) Method with respect to design parameters indicated best performance for 250–300 mm columns, reinforcement ratios of 2.5–3.5 %, effective lengths of 3–5 m, covers of 35–65 mm, and concretes of 20–60 MPa, with reduced accuracy at extreme conditions.
{"title":"Fire resistance of concrete columns: Meta-analysis of code-based methods","authors":"Mahadev Rokade, Tim Stratford, Dave Rush","doi":"10.1016/j.firesaf.2025.104626","DOIUrl":"10.1016/j.firesaf.2025.104626","url":null,"abstract":"<div><div>A dataset of 165 fire tests on rectangular concrete columns, spanning five decades, was compiled to evaluate six design methods from five international codes (Eurocode Methods A and B (ECA, ECB), Australian (AS 3600), Chinese (DBJ/T), American (ACI), and Indian (NBC)). A meta-analysis assessed their predictive reliability using historical and recent results. ECA and AS 3600 gave the most consistent and conservative predictions, with ECA performing best overall. For fire resistance ratings (FRR) < 240 min, about 70 % of ECA (2019) predictions were within ±20 % of test outcomes, though accuracy declined at longer durations. AS 3600 produced similar results due to its related formulation. ECB changed notably: 2019 method was unreliable for FRR >140 min, whereas the 2023 version aligned better with recent tests and reduced excessive conservatism. DBJ/T performed adequately on older specimens but overestimated newer ones, while ACI and NBC showed high variability and frequent unconservative predictions. Assessment of the robustness of the ECA (2023) Method with respect to design parameters indicated best performance for 250–300 mm columns, reinforcement ratios of 2.5–3.5 %, effective lengths of 3–5 m, covers of 35–65 mm, and concretes of 20–60 MPa, with reduced accuracy at extreme conditions.</div></div>","PeriodicalId":50445,"journal":{"name":"Fire Safety Journal","volume":"161 ","pages":"Article 104626"},"PeriodicalIF":3.3,"publicationDate":"2026-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145979380","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}
Pub Date : 2026-06-01Epub Date: 2026-01-08DOI: 10.1016/j.firesaf.2025.104631
Emil O. Lidman Olsson , Peter Arendt Jensen , Kim Dam-Johansen , Jochen A.H. Dreyer
The fire resistance of structural steel can be improved if it is coated with intumescent coating. Many intumescent coatings, tested according to standardized large-scale tests, are available on the market. In this work, data for 62 coatings, tested according to EN 13381-8 and/or BS 476-20/21, was compiled and analyzed. This was done to provide an overview of what fire-resistance performance can be expected from commercially available technologies and to identify trends in the data. The data shows that the fire resistance time tend to be 10–15 % lower when testing according to EN compared to BS. A comparison of data for rectangular and circular hollow sections reveals no consistent difference in fire resistance performance, indicating that any differences are a consequence of the individual coating behavior. For a given design temperature, the fire resistance time of I/H-sections is almost always higher compared to that of a corresponding hollow section. The difference was shown to be more pronounced at high section factors and/or low dry-film thicknesses. For I/H-sections, 3-sided exposure has a performance similar to 4-sided exposure, whereas rectangular hollow sections tend to have a somewhat higher fire-resistance with 3-sided exposure. Possible explanations for the observed trends are discussed in this review.
{"title":"A survey of commercial intumescent coating performance – contribution to the fire resistance of structural steel according to EN 13381 and BS 476","authors":"Emil O. Lidman Olsson , Peter Arendt Jensen , Kim Dam-Johansen , Jochen A.H. Dreyer","doi":"10.1016/j.firesaf.2025.104631","DOIUrl":"10.1016/j.firesaf.2025.104631","url":null,"abstract":"<div><div>The fire resistance of structural steel can be improved if it is coated with intumescent coating. Many intumescent coatings, tested according to standardized large-scale tests, are available on the market. In this work, data for 62 coatings, tested according to EN 13381-8 and/or BS 476-20/21, was compiled and analyzed. This was done to provide an overview of what fire-resistance performance can be expected from commercially available technologies and to identify trends in the data. The data shows that the fire resistance time tend to be 10–15 % lower when testing according to EN compared to BS. A comparison of data for rectangular and circular hollow sections reveals no consistent difference in fire resistance performance, indicating that any differences are a consequence of the individual coating behavior. For a given design temperature, the fire resistance time of I/H-sections is almost always higher compared to that of a corresponding hollow section. The difference was shown to be more pronounced at high section factors and/or low dry-film thicknesses. For I/H-sections, 3-sided exposure has a performance similar to 4-sided exposure, whereas rectangular hollow sections tend to have a somewhat higher fire-resistance with 3-sided exposure. Possible explanations for the observed trends are discussed in this review.</div></div>","PeriodicalId":50445,"journal":{"name":"Fire Safety Journal","volume":"161 ","pages":"Article 104631"},"PeriodicalIF":3.3,"publicationDate":"2026-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145979379","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}
Pub Date : 2026-06-01Epub Date: 2026-01-14DOI: 10.1016/j.firesaf.2026.104642
Jiangdong Li , Mingjian Yin , Kai Zhu , Ke Wu , Tianhang Zhang
High-temperature and toxic smoke is the primary factor of casualties in tunnel fires, particularly caused by the smoke descent due to the disruption of smoke stratification. In this work, the smoke stratification behavior is investigated considering the effects of indoor-outdoor temperature difference (ΔTie) and heat release rate (HRR) in naturally ventilated tunnel fires through full-scale experiments and numerical simulations. Results show that thermodynamic balance between internal hot smoke and external hot air induces the symmetrical temperature field and “double cycle” flow field structure, which causes the smoke re-stratification behavior. This process is characterized by smoke accumulating and spreading along the floor, while a clear air layer is maintained above. The critical boundary cooling length to trigger the smoke re-stratification (i.e., the distance between the fire source and the smoke stagnation point) increases with increasing heat release rate and decreasing indoor-outdoor temperature difference, indicating that even small fires can pose significant risks as the smoke descends more easily. By analyzing the dominant factors affecting longitudinal ceiling temperature distribution, a quantitative correlation for predicting the critical boundary cooling length through ΔTie and HRR is proposed. The prediction shows a good agreement with both the full-scale experimental and numerical results within ±5 % error. These findings uncover a novel smoke dynamic mechanism and provide a deeper understanding of the fire risks in the naturally ventilated tunnels.
{"title":"Full-scale and numerical study on the indoor-outdoor temperature difference-induced smoke Re-stratification in naturally ventilated tunnel fires","authors":"Jiangdong Li , Mingjian Yin , Kai Zhu , Ke Wu , Tianhang Zhang","doi":"10.1016/j.firesaf.2026.104642","DOIUrl":"10.1016/j.firesaf.2026.104642","url":null,"abstract":"<div><div>High-temperature and toxic smoke is the primary factor of casualties in tunnel fires, particularly caused by the smoke descent due to the disruption of smoke stratification. In this work, the smoke stratification behavior is investigated considering the effects of indoor-outdoor temperature difference (<em>ΔT</em><sub><em>ie</em></sub>) and heat release rate (<em>HRR</em>) in naturally ventilated tunnel fires through full-scale experiments and numerical simulations. Results show that thermodynamic balance between internal hot smoke and external hot air induces the symmetrical temperature field and “double cycle” flow field structure, which causes the smoke re-stratification behavior. This process is characterized by smoke accumulating and spreading along the floor, while a clear air layer is maintained above. The critical boundary cooling length to trigger the smoke re-stratification (i.e., the distance between the fire source and the smoke stagnation point) increases with increasing heat release rate and decreasing indoor-outdoor temperature difference, indicating that even small fires can pose significant risks as the smoke descends more easily. By analyzing the dominant factors affecting longitudinal ceiling temperature distribution, a quantitative correlation for predicting the critical boundary cooling length through <em>ΔT</em><sub><em>ie</em></sub> and <em>HRR</em> is proposed. The prediction shows a good agreement with both the full-scale experimental and numerical results within ±5 % error. These findings uncover a novel smoke dynamic mechanism and provide a deeper understanding of the fire risks in the naturally ventilated tunnels.</div></div>","PeriodicalId":50445,"journal":{"name":"Fire Safety Journal","volume":"161 ","pages":"Article 104642"},"PeriodicalIF":3.3,"publicationDate":"2026-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146038583","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}
Pub Date : 2026-06-01Epub Date: 2026-02-03DOI: 10.1016/j.firesaf.2026.104653
H. Prétrel, B. Kondorkuzhi, A. Savino, S. Suard
This study deals with unstable combustion regimes during a fire scenario in a mechanically ventilated enclosure, which are common in industry and particularly in nuclear facilities. These regimes are encountered for fire sources and ventilation configurations leading to oxygen deficient conditions close to the extinction limit and bring into play the mechanisms of local extinction and re ignition. This study is based on the analysis of propane gas fire experiments performed at a reduced scale in a mechanically ventilated compartment with fire heat release rate and ventilation flow rate as parameters. The variables analysed are room pressure, gas temperature and oxygen concentration in the enclosure and videos. Oscillatory combustion regimes appear for conditions of propane and ventilation flow rates in a ratio close to stoichiometry and the frequencies obtained are between 50 and 100 mHz. A comparative analysis with literature shows the influence of a fire with a constant pyrolysis rate compared to pool fires with a variable pyrolysis rate. This study provides new observations and quantitative data on unstable phenomena that can be used to validate numerical simulation attempts of these phenomena.
{"title":"Oscillatory combustion phenomenon in mechanically ventilated enclosure with propane gas fire","authors":"H. Prétrel, B. Kondorkuzhi, A. Savino, S. Suard","doi":"10.1016/j.firesaf.2026.104653","DOIUrl":"10.1016/j.firesaf.2026.104653","url":null,"abstract":"<div><div>This study deals with unstable combustion regimes during a fire scenario in a mechanically ventilated enclosure, which are common in industry and particularly in nuclear facilities. These regimes are encountered for fire sources and ventilation configurations leading to oxygen deficient conditions close to the extinction limit and bring into play the mechanisms of local extinction and re ignition. This study is based on the analysis of propane gas fire experiments performed at a reduced scale in a mechanically ventilated compartment with fire heat release rate and ventilation flow rate as parameters. The variables analysed are room pressure, gas temperature and oxygen concentration in the enclosure and videos. Oscillatory combustion regimes appear for conditions of propane and ventilation flow rates in a ratio close to stoichiometry and the frequencies obtained are between 50 and 100 mHz. A comparative analysis with literature shows the influence of a fire with a constant pyrolysis rate compared to pool fires with a variable pyrolysis rate. This study provides new observations and quantitative data on unstable phenomena that can be used to validate numerical simulation attempts of these phenomena.</div></div>","PeriodicalId":50445,"journal":{"name":"Fire Safety Journal","volume":"161 ","pages":"Article 104653"},"PeriodicalIF":3.3,"publicationDate":"2026-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146189455","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}
Pub Date : 2026-06-01Epub Date: 2026-01-24DOI: 10.1016/j.firesaf.2026.104646
Jun Yan , Chao Zhang , Shu-jian Yu
High-temperature creep deformations and rupture critically affect the fire response of high-strength structural steel (HSSS) structures. Limited data exist on the influence of temperature and stress on creep behavior in HSSS used in construction. This study presents an experimental investigation of temperature-induced creep in Q550, Q690, and Q890 steels commonly employed in structural members. Creep tests were conducted at various stress levels within the 550–700 °C range, a temperature span commonly encountered in fire-exposed structures. The results show that temperature and stress strongly influence creep deformations in HSSSs. At high temperatures, all three HSSSs fail by ductile fracture, characterized by pronounced plastic elongation and necking. A critical temperature exists for each stress level, below which creep is confined to the primary and secondary stages; above this temperature, HSSSs enter tertiary creep, ultimately leading to rupture. The creep mechanisms and damage modes of HSSSs are strongly temperature dependent. Below 650 °C, creep is dominated by dislocation-controlled mechanisms with damage mainly from void growth, whereas at temperatures above 650 °C, creep transitions to diffusion- or grain-boundary-dominated processes accompanied by accelerated damage evolution and reduced creep resistance.
{"title":"Creep deformation and rupture behavior of high-strength structural steel over 500 MPa at elevated temperature","authors":"Jun Yan , Chao Zhang , Shu-jian Yu","doi":"10.1016/j.firesaf.2026.104646","DOIUrl":"10.1016/j.firesaf.2026.104646","url":null,"abstract":"<div><div>High-temperature creep deformations and rupture critically affect the fire response of high-strength structural steel (HSSS) structures. Limited data exist on the influence of temperature and stress on creep behavior in HSSS used in construction. This study presents an experimental investigation of temperature-induced creep in Q550, Q690, and Q890 steels commonly employed in structural members. Creep tests were conducted at various stress levels within the 550–700 °C range, a temperature span commonly encountered in fire-exposed structures. The results show that temperature and stress strongly influence creep deformations in HSSSs. At high temperatures, all three HSSSs fail by ductile fracture, characterized by pronounced plastic elongation and necking. A critical temperature exists for each stress level, below which creep is confined to the primary and secondary stages; above this temperature, HSSSs enter tertiary creep, ultimately leading to rupture. The creep mechanisms and damage modes of HSSSs are strongly temperature dependent. Below 650 °C, creep is dominated by dislocation-controlled mechanisms with damage mainly from void growth, whereas at temperatures above 650 °C, creep transitions to diffusion- or grain-boundary-dominated processes accompanied by accelerated damage evolution and reduced creep resistance.</div></div>","PeriodicalId":50445,"journal":{"name":"Fire Safety Journal","volume":"161 ","pages":"Article 104646"},"PeriodicalIF":3.3,"publicationDate":"2026-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146078439","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}
Predicting fire behavior in compartments with exposed timber surfaces is of critical importance to the fire safety community, given the widespread use of timber in modern buildings as both a structural and valuated for environmental aspect and the overall quality of space it creates when exposed. Fire safety engineers are particularly interested in understanding fire initiation and growth, heat release contribution, self-extinguishment conditions, and the charring behavior of wood. This study evaluates the predictive performance of Fire Dynamics Simulator (FDS) and its recently integrated pyrolysis model, S-Pyro, with respect to these key parameters. Experimental tests were conducted in medium- and large-scale compartments with exposed timber elements. A parameter sensitivity analysis was first performed on one medium-scale configuration. The results demonstrate that FDS provides accurate predictions of ignition times, fire growth rates, and heat release rates across both scales. The model also reproduced char layer thickness qualitatively at the end of the experiments. However, FDS exhibited limitations in predicting self-extinguishment in certain scenarios, highlighting the need for further investigation into this complex phenomenon in future studies.
{"title":"Evaluation of FDS scaling-pyrolysis model in predicting ignition, self-extinguishment and heat release contribution in timber compartments","authors":"Ouassim Benaroussi , Gildas Auguin , Alain Coimbra , François Consigny","doi":"10.1016/j.firesaf.2026.104640","DOIUrl":"10.1016/j.firesaf.2026.104640","url":null,"abstract":"<div><div>Predicting fire behavior in compartments with exposed timber surfaces is of critical importance to the fire safety community, given the widespread use of timber in modern buildings as both a structural and valuated for environmental aspect and the overall quality of space it creates when exposed. Fire safety engineers are particularly interested in understanding fire initiation and growth, heat release contribution, self-extinguishment conditions, and the charring behavior of wood. This study evaluates the predictive performance of Fire Dynamics Simulator (FDS) and its recently integrated pyrolysis model, S-Pyro, with respect to these key parameters. Experimental tests were conducted in medium- and large-scale compartments with exposed timber elements. A parameter sensitivity analysis was first performed on one medium-scale configuration. The results demonstrate that FDS provides accurate predictions of ignition times, fire growth rates, and heat release rates across both scales. The model also reproduced char layer thickness qualitatively at the end of the experiments. However, FDS exhibited limitations in predicting self-extinguishment in certain scenarios, highlighting the need for further investigation into this complex phenomenon in future studies.</div></div>","PeriodicalId":50445,"journal":{"name":"Fire Safety Journal","volume":"161 ","pages":"Article 104640"},"PeriodicalIF":3.3,"publicationDate":"2026-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146038584","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}
Pub Date : 2026-06-01Epub Date: 2026-01-30DOI: 10.1016/j.firesaf.2026.104649
Morteza Kamalvand , Ali Massumi , Patrick Bamonte , Peyman Homami
In high-seismic regions, design codes emphasize the critical role of RC beam-column joints; however, fire exposure can induce significant, unpredictable changes in the strength and ductility crucial for resisting future earthquakes. This paper proposes a detailed nonlinear finite element framework, incorporating three approaches of varying complexity, to evaluate the residual seismic behavior of RC beam-column joints through a sequential two-stage analysis involving heat transfer and subsequent mechanical loading. The first approach (A1) uses nodal temperatures at the end of the heating phase, assuming they represent peak fire temperatures. The second approach (A2) determines maximum nodal temperatures from the full heating-cooling history to capture delayed peaks caused by thermal inertia. The third and most comprehensive approach (A3) involves a sequential coupled analysis including the cooling phase, explicitly accounting for irreversible material damage, followed by lateral loading in the subsequent step. These methodologies were implemented via the integration of custom Python scripts and user-defined subroutines. The framework was validated against experimental data for both RC beams under fire and post-fire seismic behavior of joints, demonstrating good agreement with test results. Parametric studies revealed that extended heating duration (up to 120 min) severely degrades structural integrity, reducing initial stiffness by up to 62%. Crucially, the cooling rate significantly influences the post-fire behavior; by neglecting thermal lag, A1 yields unconservative results in slow-cooling scenarios, whereas A2 and A3 estimate the residual stiffness to be 38% and 21% lower, respectively. Furthermore, gravity loads were identified as a critical factor inducing seismic asymmetry; under a gravity load ratio of 55%, A3 predicted column instability during the cooling phase. These findings underscore that while simplified approaches suffice for strength estimation in mild scenarios, the comprehensive strategy is indispensable for assessing residual seismic characteristics and stability under high gravity loads and extended fire exposure.
{"title":"Development and implementation of staged numerical approaches for post-fire seismic assessment of RC beam-column joints","authors":"Morteza Kamalvand , Ali Massumi , Patrick Bamonte , Peyman Homami","doi":"10.1016/j.firesaf.2026.104649","DOIUrl":"10.1016/j.firesaf.2026.104649","url":null,"abstract":"<div><div>In high-seismic regions, design codes emphasize the critical role of RC beam-column joints; however, fire exposure can induce significant, unpredictable changes in the strength and ductility crucial for resisting future earthquakes. This paper proposes a detailed nonlinear finite element framework, incorporating three approaches of varying complexity, to evaluate the residual seismic behavior of RC beam-column joints through a sequential two-stage analysis involving heat transfer and subsequent mechanical loading. The first approach (A1) uses nodal temperatures at the end of the heating phase, assuming they represent peak fire temperatures. The second approach (A2) determines maximum nodal temperatures from the full heating-cooling history to capture delayed peaks caused by thermal inertia. The third and most comprehensive approach (A3) involves a sequential coupled analysis including the cooling phase, explicitly accounting for irreversible material damage, followed by lateral loading in the subsequent step. These methodologies were implemented via the integration of custom Python scripts and user-defined subroutines. The framework was validated against experimental data for both RC beams under fire and post-fire seismic behavior of joints, demonstrating good agreement with test results. Parametric studies revealed that extended heating duration (up to 120 min) severely degrades structural integrity, reducing initial stiffness by up to 62%. Crucially, the cooling rate significantly influences the post-fire behavior; by neglecting thermal lag, A1 yields unconservative results in slow-cooling scenarios, whereas A2 and A3 estimate the residual stiffness to be 38% and 21% lower, respectively. Furthermore, gravity loads were identified as a critical factor inducing seismic asymmetry; under a gravity load ratio of 55%, A3 predicted column instability during the cooling phase. These findings underscore that while simplified approaches suffice for strength estimation in mild scenarios, the comprehensive strategy is indispensable for assessing residual seismic characteristics and stability under high gravity loads and extended fire exposure.</div></div>","PeriodicalId":50445,"journal":{"name":"Fire Safety Journal","volume":"161 ","pages":"Article 104649"},"PeriodicalIF":3.3,"publicationDate":"2026-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146189453","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}
This study investigated correlations among several feelings (fear, worry, tension, and confusion) and their impact on walking speed in smoke by a full-scale tunnel evacuation experiment and questionnaires, with the aim of clarifying the mechanisms behind changes in walking speed from an emotional aspect. The results obtained through structural equation modeling indicated that feelings were mutually correlated; 72% of the participants reported experiencing multiple feelings, in which the most common combination was worry and tension. Furthermore, fear increased walking speed; the mean walking speed declined as the number of feelings increased. These findings suggest that rapid evacuation could be achieved by controlling evacuees’ feelings.
{"title":"Association of walking speed with psychological state: An experiment in smoke-filled full-scale tunnel","authors":"Wenhao Li , Miho Seike , Akimasa Fujiwara , Takafumi Sasaoka , Makoto Chikaraishi , Shigeto Yamawaki","doi":"10.1016/j.firesaf.2026.104645","DOIUrl":"10.1016/j.firesaf.2026.104645","url":null,"abstract":"<div><div>This study investigated correlations among several feelings (fear, worry, tension, and confusion) and their impact on walking speed in smoke by a full-scale tunnel evacuation experiment and questionnaires, with the aim of clarifying the mechanisms behind changes in walking speed from an emotional aspect. The results obtained through structural equation modeling indicated that feelings were mutually correlated; 72% of the participants reported experiencing multiple feelings, in which the most common combination was worry and tension. Furthermore, fear increased walking speed; the mean walking speed declined as the number of feelings increased. These findings suggest that rapid evacuation could be achieved by controlling evacuees’ feelings.</div></div>","PeriodicalId":50445,"journal":{"name":"Fire Safety Journal","volume":"161 ","pages":"Article 104645"},"PeriodicalIF":3.3,"publicationDate":"2026-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146078443","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}
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