Fire, Volume 8, Issue 12 (December 2025) – 31 articles

The widespread use of mezzanine racks in modern logistics warehouses has significantly increased fire hazards owing to the dense storage of combustibles. However, systematic full-scale studies examining the influence of shelf spacing on radiative ignition between adjacent racks are lacking. In this study, we investigate the effect of shelf spacing on radiative flame spread using full-scale fire tests and cone calorimeter experiments. The decrease in radiative heat flux with an increase in the distance was consistent with the inverse square law. Adjacent shelf ignition was prevented when the spacing was at least 5 m. Cone calorimeter tests identified a critical radiant heat flux of approximately 8 kW/m², and the ignition time decreased nonlinearly from 207.8 to 69.6 s as the radiant flux increased from 10 to 16 kW/m². These findings were cross-validated with the full-scale results, which indicated that a minimum spacing of 5 m serves as a radiative flame-spread barrier under similar storage and ventilation conditions. This study provides practical guidance for the fire-safety design of mezzanine rack warehouses. The effects of storage geometry, surface reflectivity, ventilation, active protection systems, and varying storage densities may be considered in future work to ensure broader applicability. Full article

Pressed-in ventilation provides the possibility of implementing fire smoke control in tunnels during construction. In this study, the impact of the velocity at the air duct outlet, the heat release rate (HRR), and the tunnel geometry on the longitudinal temperature decay of the ceiling (ΔT) and smoke’s back-layering length (SBL) is investigated, using a reduced-scale experiment and the Fire Dynamics Simulator (FDS, version 6.7.6). The results indicate that an increase in the velocity at the air duct outlet and a decrease in the HRR lead to a reduction in the value of both ΔT and SBL in the main tunnel. Predictive models for the dimensionless longitudinal temperature decay of the ceiling and the dimensionless SBL are proposed. Near the fire source, the predicted SBL is relatively high due to thermal radiation. The research results provide valuable references for preventing tunnel fires during construction. Full article

This study investigates the impact of aging on the thermal runaway behavior of lithium-ion batteries. By combining external heating tests, cone calorimetry experiments, and numerical simulations, the thermal runaway characteristics of LFP and NMC batteries at different SOH levels (100%, 90%, 80%) were systematically evaluated. Experimental results show a non-monotonic effect of aging on thermal runaway: mildly aged batteries (90% SOH) exhibited the earliest TR trigger and highest risk due to unstable SEI film growth, while new batteries (100% SOH) released the most energy. Significant differences were observed between battery chemistries: LFP batteries displayed fluctuating temperature curves indicating a staged buffering mechanism, whereas NMC batteries had smooth heating but abrupt energy release. Cone calorimeter tests revealed that aged LFP batteries had multi-stage HRR curves, while NMC batteries showed consistent HRR profiles; mass loss data confirmed reduced active material consumption with aging. Numerical simulations integrating SEI decomposition and other reactions validated the impact of aging on internal processes. The study recommends prioritizing monitoring of moderately aged batteries, optimizing early-warning systems for NMC batteries, and preventing secondary explosions, providing support for safety assessments of aged batteries. Full article

The wildland fire management system is increasingly complex and uncertain, which challenges suppression actions and increases stress on an already strained system. Researchers and managers have called for the use of strategic, risk-informed decision making and decision support tools (DSTs) in wildfire management to manage complexity and mitigate uncertainty. This paper evaluated the use of an emerging wildfire DST, the Risk Management Assistance (RMA) dashboard, during the 2021 and 2022 wildfire seasons. We used a mixed-method approach, consisting of an online survey and in-depth interviews with fire managers. Our objectives were the following: (1) to determine what factors at multiple scales facilitated and frustrated the adoption of RMA; and (2) to identify actionable recommendations to facilitate uptake of RMA. We situate our findings within the diffusion of innovations literature and use-inspired research. Most respondents indicated RMA tools were easy to use, accurate, and relevant to decision-making processes. We found evidence that the tools were used throughout the fire management cycle. Previous experience with RMA and training in risk management, trust in models, leadership support, and perceptions of current and future fire risk affected RMA adoption. Recommendations to improve RMA included articulating how the tools integrate with existing wildland fire DSTs, new tools that consider dynamic forecasting of risk, and both formal and informal learning opportunities in the pre-season, during incidents, and in post-fire reviews. We conclude with research and management considerations to increase the use of RMA and other DSTs in support of safe, effective, and informed wildfire decision making. Full article

Against the backdrop of intensifying global climate change and human activities, the increasing frequency and evolution of major wildfire events pose severe challenges to global disaster prevention and mitigation systems. Systematically understanding their disaster characteristics, spatiotemporal patterns, and societal response efficacy is an urgent scientific requirement for formulating effective coping strategies. This study constructed a comprehensive database covering 137 major global wildfire events from 2018 to 2024, with data sourced from GFED, EM-DAT, and official national reports. Utilizing a synthesis of methods including descriptive statistics, spatiotemporal clustering analysis, K-means pattern recognition, and non-parametric tests, a multi-dimensional quantitative analysis was conducted on disaster characteristics, evolutionary trends, casualty patterns, and policy effectiveness. Despite potential reporting biases and heterogeneous data standards across countries, the analysis reveals the following: (1) All key wildfire metrics (e.g., burned area, casualties, evacuation scale) exhibited extreme right-skewed distributions, indicating that a minority of catastrophic events dominate the overall risk profile; (2) Global wildfire hotspots demonstrated dynamic expansion, spreading from traditional regions in North America and Australia to emerging areas such as Mediterranean Europe, Chile, and the Russian Far East, forming three significant spatiotemporal clusters; (3) Four distinct casualty patterns were identified: “High-Lethality”, “Large-Scale Evacuation”, “Routine-Control”, and “Ecological-Destruction”, revealing the differentiated formation mechanisms under various disaster scenarios; (4) A substantial gap of nearly 65 times in emergency evacuation efficiency—defined as the ratio of evacuated individuals to total casualties—was observed between developed and developing countries, highlighting a significant “development gap” in emergency management capabilities. This study finds evidence of increasing extremization, expansion, and polarization in global wildfire risk within the 2018–2024 event sample. The conclusions emphasize that future risk management must shift from addressing “normal” events to prioritizing preparedness for “catastrophic” scenarios and adopt refined strategies based on casualty patterns. Simultaneously, the international community needs to focus on bridging the emergency response capability gap between nations to collectively build a more resilient global wildfire governance system. Full article

This study investigates the effect of the flame tube convergent segment wall configuration on the performance of a High-Temperature-Rise (HTR) triple-swirler main combustor. Three configurations were evaluated: the Vitosinski principle (Scheme A), the equal velocity gradient criterion (Scheme B), and a novel convex-arc flow-facing method (Scheme C). Three-dimensional numerical simulations were conducted using validated RANS equations with the Realizable k-ε turbulence model and a non-premixed PDF combustion model. The results demonstrate that the proposed Scheme C, characterized by an inflection-free convex contour, successfully avoids the localized high-velocity region and achieves a more uniform flow field. A systematic comparison reveals that Scheme C achieves the highest outlet temperature distribution quality (lowest OTDF and RTDF), the highest combustion efficiency, and the lowest total pressure loss (TPL) in the convergent segment among the three designs. In conclusion, the comprehensive analysis confirms that the convex-arc design (Scheme C), by eliminating the geometric discontinuity of an inflection point, provides the best overall performance for the HTR combustor under takeoff conditions. Full article

Wildfires are a recurring dry-season hazard in northern Thailand, contributing to severe air pollution and trans-boundary haze. However, the region lacks the ground-based measurements necessary for monitoring Live Fuel Moisture Content (LFMC), a key variable influencing vegetation flammability. This study presents a preliminary framework for near-real-time (NRT) LFMC estimation using Sentinel-2 multispectral imagery. The system integrates normalized vegetation and moisture-related indices, including the Normalized Difference Vegetation Index (NDVI), the Normalized Difference Infrared Index (NDII), and the Moisture Stress Index (MSI) with an NDVI-derived evapotranspiration fraction (ETf) within a heuristic modeling approach. The workflow includes cloud and shadow masking, weekly to biweekly compositing, and pixel-wise normalization to address the persistent cloud cover and heterogeneous land surfaces. Although currently unvalidated, the LFMC estimates capture the relative spatial and temporal variations in vegetation moisture across northern Thailand during the 2024 dry season (January–April). Evergreen forests maintained higher moisture levels, whereas deciduous forests and agricultural landscapes exhibited pronounced drying from January to March. Short-lag responses to rainfall suggest modest moisture recovery following precipitation, although the relationship is influenced by additional climatic and ecological factors not represented in the heuristic model. LFMC-derived moisture classes reflect broad seasonal dryness patterns but should not be interpreted as direct fire danger indicators. This study demonstrates the feasibility of generating regional LFMC indicators in a data-scarce tropical environment and outlines a clear pathway for future calibration and validation, including field sampling, statistical optimization, and benchmarking against global LFMC products. Until validated, the proposed NRT LFMC estimation product should be used to assess relative vegetation dryness and to support the refinement and development of future operational fire management tools, including early warnings, burn-permit regulation, and resource allocation. Full article

Lightning-ignited wildfires represent a dominant natural disturbance agent in the Greater Khingan Mountains of northeastern China; however, the relationship between their occurrence and lightning characteristics remains insufficiently quantified. This study analyzed cloud-to-ground (CG) lightning data (2019–2024) and 417 lightning-ignited wildfires (2019–2024) using a full-waveform lightning detection network and spatial matching based on the Minimum Distance Method. Lightning activity shows pronounced spatiotemporal clustering, with more than 93% of flashes occurring in summer and a diurnal peak at 15:00. About 74.6% of wildfires ignited within 1 km of a lightning strike, and the holdover time exhibited clear seasonality, peaking in August (≈317 h). Negative CG (−CG) flashes dominated ignition events (56.5% multiple-stroke, average multiplicity = 2.60), and igniting flashes were concentrated within the −10 to −30 kA peak-current range, suggesting a key threshold for ignition. Vegetation type strongly influenced ignition efficiency: cold temperate and temperate coniferous forests recorded the highest lightning and fire counts, while alpine grasslands and sedge meadows showed the highest lightning ignition efficiency (LIE). These findings clarify how lightning electrical properties and vegetation conditions jointly determine ignition probability and provide a scientific basis for improving lightning-ignited wildfire risk monitoring and early-warning systems in boreal forest regions. Full article

Fire incidents pose a significant threat to urban communities. However, the inherent vulnerability of old communities to fire incidents is often overlooked, resulting in a lack of targeted evaluation methods for old community fire resilience (OCFR). Therefore, this study aims to propose a comprehensive evaluation model to systematically measure the level of OCFR. Initially, an evaluation indicator system for the OCFR was developed based on the pressure–state–response (PSR) model and 4M (man, machine, media, management) theory. Subsequently, an integrated evaluation model combining the coefficient of variation (COV) and the fuzzy comprehensive evaluation (FCE) approach was established to ensure objective weighting and reliable assessment. Finally, the Community W in Xuzhou City of China was selected as a typical case, and data from 210 valid resident questionnaires were utilized to evaluate its OCFR and propose targeted improvement strategies. The key findings indicate that the ‘state’ dimension holds the largest weight, with the top-weighted indicators being OCFR210 (firefighting investment development), OCFR211 (disaster prevention education and publicity), and OCFR214 (emergency rescue organization and management). The OCFR score for Community W was 70.256, placing it in the ‘good’ level. Furthermore, sensitivity analysis revealed the robustness of the evaluation model for OCFR. This research not only introduces a novel evaluation model that expands the body of knowledge on fire resilience but also provides practical strategies to mitigate fire risks and enhance fire management in old communities, with the ultimate goal of reducing community fire incidents. Full article

To investigate the fire suppression effectiveness of perfluorohexanone in low-pressure environments, a self-built fire suppression experimental platform was utilized to analyze the influence of ambient pressure and heat release rate on its performance. The results demonstrate that under normal-pressure conditions, the extinguishing time increases with the heat release rate of the fire source, whereas under low-pressure conditions, the extinguishing time decreases as the heat release rate increases. Specifically, under normal pressure, the extinguishing times for Fire Pan A (10 cm × 10 cm × 10 cm), Fire Pan B (15 cm × 15 cm × 10 cm), and Fire Pan C (20 cm × 20 cm × 10 cm) were 5.03 s, 8.15 s, and 9.63 s, respectively. In contrast, under low pressure, the extinguishing times were significantly shorter, with reductions of 2.8 s, 6.59 s, and 8.45 s, respectively. In terms of temperature reduction, the flame temperature decreased by approximately 300 °C under normal pressure, while under low pressure, it decreased by only about 100 °C. The concentration of hydrogen fluoride (HF) produced after extinguishment was relatively low, indicating limited toxicity. The HF concentration under normal pressure was, on average, approximately 59.2% higher than that under low-pressure conditions. Based on parameters such as the mass of the extinguishing agent, temperature changes, and hydrogen fluoride content, a fire suppression effectiveness model was established. The results show that the weight coefficient for chemical inhibition intensity is as high as 38.81, significantly exceeding other factors, demonstrating that perfluorohexanone primarily relies on chemical inhibition to interrupt the combustion chain reaction. This conclusion provides an important theoretical basis for the design and optimization of fire suppression systems in low-pressure environments such as aviation and high-altitude areas. Full article

Wildfires are a major source of greenhouse gases (GHGs), particulate matter (PM), and atmospheric pollutants, exerting widespread impacts on air quality, human health, and global climate. To address knowledge gaps, this study conducts a literature review of GHG emissions from wildfires across diverse ecosystems and fire regimes. The analysis quantifies emission magnitudes and compositions, evaluates their influence on regional and global climate processes, and synthesizes trends and methodological advances. Results show that the burned area is the main determinant of total emissions, with CO₂ as a robust predictor for estimated CO and CH₄, reflecting coupled emission behavior under varying combustion conditions. The Modified Combustion Efficiency (MCE) demonstrates a stronger predictive capacity for the CO/CO₂ ratio than for CH₄/CO₂, suggesting that CO/CO₂ can be predicted from MCE. Complete combustion dominates most fire events, while incomplete combustion increases the release of CO, CH₄, N₂O, and PM, contributing to tropospheric ozone formation and enhanced radiative forcing. Exposure to PM_2.5 and ozone remains a major health concern in fire-affected regions. This review provides a quantitative synthesis linking combustion efficiency and GHG co-variability, offering insights to refine emission modeling and guide climate mitigation strategies. Full article

Car parks are a vital component of infrastructure in modern cities. However, fire in car park buildings may lead to significant structural damage and casualties, highlighting the urgent need for fast forecasting methods. Traditional simulation methods are computationally prohibitive for immediate decision-making during a fire incident. This study develops a unified deep learning architecture for a real-time prediction of both the temperature distribution and structural response in car park fires. A numerical database was established using FDS and Abaqus, considering key variables including fire size, fire location and load level. A deep learning model based on the convolutional neural network and long short-term memory networks was proposed. The model takes a 10 s history of gas temperatures from ceiling sensors and the applied load level as input to give predictions on the spatial temperature distribution at a 2 m height 3 min into the future and the vertical deflection of the slab edge for up to 5 h after fire ignition. The model achieved high accuracy, with R² values of 92% for temperature prediction and 95% for deflection prediction. This study provides a new approach for real-time fire and structural safety early warning. Full article

Prescribed fire is a critical land management practice in the Great Plains of North America, helping to maintain native rangelands and reduce wildfire risk. Barriers to prescribed fire practice remain due to concerns on potential fire escape and fire danger. A localized fire danger index can help address these concerns by providing clear, science-based guidance, encouraging safer and confident use of prescribed fire. Our goal is to support the development of a localized Grassland Fire Danger Index (GFDI) for prescribed fire management in the Great Plains. The specific objective of this study is to develop user-friendly sub-models for dead fuel moisture content (DFMC) and grass curing, which serve as components of the proposed GFDI. DFMC reflects short-term fuel moisture that affects ignition and fire spread, while grass curing represents seasonal drying that controls fuel availability. Both are critical for fire prediction and safe burns. Lower DFMC and higher grass curing levels are strongly associated with wildfire risks. Using Oklahoma Mesonet weather data, the DFMC sub-model improves the accuracy and sensitivity of existing models. The grass curing sub-model shows that 50% curing usually occurs around April 15–16, which matches the time for the most intensive prescribed fire activities in the region, indicating it as a safe and effective window for prescribed fire recognized by landowners. Our sub-models lay the foundation for development of GFDI in the region. Full article

This research employs an integrated experimental and numerical simulation approach to investigate how varying angles of continuous elbows in a “Z”-shaped pipeline affect the deflagration behavior of hydrogen-propane-air mixtures. Findings indicate that centrifugal forces acting on the flame front as it traverses an elbow cause a distinctive “tongue-shaped” propagation along the inner wall. A cavity that generates unburned gas near the outer wall. The volume of this cavity increases significantly with the Angle of the elbow. The flame propagation is regulated by it and presents three distinct stages: the initial development section within the straight pipe section, the disturbance section when entering the first elbow, and the subsequent suppression section under the action of the cavity. The more intense turbulent combustion occurs at the 90° bend, with the highest peak flame velocity. On the contrary, the 120° and 150° elbows suppress the spread of flames. In addition, the angle of the elbow has a significant effect on the second overpressure peak, which exhibits strong non-linear growth. The value at 150° is 2.7 times greater than that at 30°. This is mainly caused by the energy focusing effect of the reflected pressure wave in the cavity magnified by the large-angle elbow. These findings provide mechanism-level understanding for the safe design of complex hydrogen pipeline systems. Full article

Fire is a key driver of ecosystem dynamics under global change, and understanding its complex relationship with the climate system is crucial for regional wildfire risk management and the development of ecological adaptation strategies. The western United States is a critical region for studying fire–climate interactions due to its pronounced environmental gradients, diverse fire regimes, and high vulnerability to climate change, which together provide a robust natural laboratory for examining spatial variability in fire responses. Based on tree-ring fire-scar records systematically collected from five major ecoregions in the western United States via the International Tree-Ring Data Bank (ITRDB), this study reconstructed fire history sequences spanning 430–454 years. By integrating methods such as correlation analysis, random forest regression, superposed epoch analysis, and effect size assessment, we systematically revealed the spatial differentiation patterns of fire frequency and fire spatial extent across different ecoregions, quantified the relative contributions of key climatic drivers, and identified climatic anomaly characteristics during extreme fire years. The results indicate that: (1) there are significant differences in fire frequency between different ecological areas; (2) summer drought conditions (PDSI) are the most consistent and strongest driver of fire across all ecoregions, and ENSO (NINO3) also shows a widespread negative correlation; (3) random forest models indicate that the Sierra Nevada and Madrean Archipelago ecoregions are the most sensitive to multiple climatic factors, while fire in regions such as the Northern Rockies may be more regulated by non-climatic processes; (4) extreme fire years across all ecoregions are associated with significant negative PDSI anomalies with prominent effect sizes, confirming that severe drought is the dominant cross-regional precondition for extreme fire events. This study emphasizes the region-specific nature of fire–climate relationships and provides a scientific basis for developing differentiated, ecoregion-specific fire prediction models and prevention strategies. The methodological framework and findings offer valuable insights for fire regime studies in other global forest ecosystems facing similar climate challenges. Full article

Forest fires continue to pose a significant threat to public and personal safety. Detecting smoke in its early stages or when it is distant from the camera is challenging because it appears in only a small region of the captured images. This paper proposes a small-scale smoke detection algorithm called TCSN-YOLO to address these challenges. First, it introduces a novel feature fusion module called trident fusion (TF), which is innovatively designed and incorporated into the neck of the model. TF significantly enhances small target smoke recognition. Additionally, to obtain global contextual information with high computational efficiency, we propose a Cross Attention Mechanism (CAM). CAM captures diverse smoke features by assigning attention weights in both horizontal and vertical directions. Furthermore, we suggest using SoftPool to preserve more detailed information in the feature map. Normalized Wasserstein Distance (NWD) metric be embedded into the loss function of our detector to distinguish positive and negative samples under the same threshold. Finally, we evaluate the proposed model using AI For Humankind dataset and FlgLib dataset. The experimental results demonstrate that our method achieves 37.1% APs, 90.3% AP50, 40.4% AP50:95, 45.34 M Params and 170.5 G FLOPs. Full article

Type IV composite overwrapped pressure vessels—characterized by a polymer liner fully wrapped in fiber-reinforced polymer—are emerging as lightweight, corrosion-proof alternatives to traditional metal cylinders in fire safety applications. This paper presents a comprehensive review of Type IV high-pressure vessels used in portable fire extinguishers and self-contained breathing apparatus (SCBA) systems. We outline recent material innovations for both the non-metallic liners and composite shells, including multilayer liner designs (e.g., high-barrier polymers and nanocomposites) and advanced fiber/resin systems. Key manufacturing developments such as automated filament winding, resin infusion, and in-line non-destructive testing are discussed. Technical performance in fire applications is critically examined: current standards and certification requirements (EU and international), typical design pressures (e.g., 300 bar in SCBA) and safety factors, common failure modes (liner collapse, fiber rupture, etc.), inspection protocols, and a comparison with Type IV hydrogen storage cylinders. Market trends are also reviewed, highlighting the major manufacturers and the growing adoption of composite extinguishers (e.g., 20-year service-life composite units) versus conventional steel. The review draws on 7–10 peer-reviewed studies to analyze the state of the art, finding that Type IV vessels offer significant weight reduction (>30%) and corrosion resistance at the cost of more complex design and certification. In firefighting use, these cylinders demonstrably improve firefighter mobility and reduce maintenance, while meeting rigorous safety standards. Remaining challenges include further improving liner permeability barriers to prevent gas leakage or collapse, understanding long-term composite aging under cyclic loads, and optimizing fire resistance. Overall, Type IV composite pressure vessels represent a major innovation in fire suppression technology, enabling safer and more efficient extinguishing equipment. Future research and standardization efforts are recommended to fully realize their benefits in fire protection. Full article

The safe operation of hydrogen transmission pipeline stations is paramount for the widespread adoption of hydrogen energy. This study addresses the significant hazard of hydrogen leakage in high-pressure pipeline stations by employing numerical simulations to investigate the dispersion behavior under various conditions. It specifically focuses on the complex interplay between meteorological factors, operational parameters, and station layout. A key finding is that the structural configuration of obstacles—namely their height and distance from the leakage source—serves as the dominant mechanism controlling the evolution of the hazard radius, overshadowing the influence of traditional parameters like wind speed and leak diameter in obstructed environments. Based on this insight, a novel and robust predictive model for the dynamic hazard radius was developed using multiple regression analysis. The model accurately quantifies the impact of leakage duration, obstacle spacing, and obstacle height, achieving an excellent fit (R² = 0.9848) with a prediction error of less than 5% compared to simulation data. This study provides valuable insights for defining risk zones and supports the development of effective safety measures and emergency response strategies for hydrogen infrastructure, thereby contributing to the secure and sustainable deployment of hydrogen energy. Full article

Addressing the environmental challenges posed by traditional foam extinguishing agents containing persistent pollutants, the development of eco-friendly alternatives has become imperative. This study investigates the effect of xanthan gum (XG) on the fire extinguishing performance of PFH-BZ foam formulated with short-chain fluorocarbon surfactant. By analyzing foam formation, drainage characteristics, and suppression process, the underlying mechanism by which XG influences foam extinguishing performance was elucidated. The results indicate that XG exerts dual effects on foam properties. While its viscosity-increasing effect improves foam stability, excessive XG addition impairs foaming and spreading capabilities, reducing fuel surface coverage and smothering efficiency. Moreover, a high concentration of XG hinders drainage behavior, which in turn inhibits the formation of spreadable aqueous films, thereby reducing cooling and extinguishing efficiency. The PFH-BZ foam with 0.02 wt.% XG exhibits excellent foaming and spreading capabilities, enabling rapid coverage of fuel surfaces. Additionally, its moderate drainage characteristics facilitate spreadable aqueous film formation, achieving efficient cooling and smothering effects. The optimized PFH-BZ foam exhibits the shortest extinction time of 35.4 s, the lowest transient temperature rise of 60.8 °C, and the highest cooling rate of 16.8 °C/s. Environmental assessments reveal that the optimized PFH-BZ foam exhibits higher biodegradability than conventional foam. Full article

To mitigate the limitations of low measurement accuracy and substantial environmental interference in UAV-based TIR imaging for coal fire monitoring, this study presents an integrated temperature correction approach, termed NRBO-XGBoost. The proposed method applies temperature correction to TIR imagery and subsequently investigates coal fire detection using the corrected TIR data. By leveraging multi-source data (thermal infrared measurements, UAV flight altitude, and meteorological parameters), the NRBO optimizes XGBoost hyperparameters to improve model convergence speed and global search capability, effectively overcoming the limitations of traditional methods, such as local optima entrapment and poor generalization. Experimental results demonstrate that the NRBO-XGBoost model achieves superior performance in temperature correction, with a coefficient of determination (R²) of 0.9993, while reducing RMSE and MAE by 85.6% and 86.6%, respectively. Notably, the model exhibits enhanced stability in high-temperature regions (>300 °C). The 3D reconstruction results demonstrate a nearly 6-fold expansion in high-temperature area coverage (from 0.43% to 2.60%), coupled with a morphological transformation of fragmented hotspots into continuous, belt-shaped distributions. Integrating visible-light textures further improves boundary clarity and spatial semantic representation of thermal anomalies. This study provides a high-precision temperature correction and 3D visualization solution for coal fire monitoring, offering critical technical support for early warning systems and firefighting strategies. Full article

The aviation industry needs to develop sustainable, fire-safe cabin interior materials. Although wood is eco-friendly, its high flammability makes it challenging to meet flame retardant standards. Enhancing wood fire safety requires the creation of an environmentally friendly and flame retardant coating. In this study, a new type of intumescent flame retardant (IFR) coating was applied to the wood surface using the layer-by-layer (LBL) technique, with fully bio-based chitosan (CS), agar, and phytic acid (PA) as key components. The coated wood demonstrated improved durability, flame resistance, and thermal stability. Particularly, the Wood-2 sample achieved a vertical burning test (UL-94) V-0 rate and a limiting oxygen index (LOI) of 53.1%, which exceeded most previous reported flame retardant coatings. Cone calorimeter test and infrared thermography analysis confirmed that a thick layer of intumescent char formed when the coating was exposed to heat, effectively hindering heat transfer and oxygen supply. This flame retardant effect is attributed to a synergistic mechanism involving nitrogen/phosphorus (N/P) elements. This study offers an environmentally friendly solution for wood flame retardancy and lays an experimental and theoretical foundation for the development of green aviation interior materials. Full article

The study of the behaviour of steel reinforcement in high temperatures is essential to understanding the performance of structural concrete after a fire. A special case is presented by steel reinforcements that are exposed to high temperatures after losing all or part of the nominal coating that protects them. In this work, detailed research has been carried out to understand the behaviour of two types of steel, B500SD (carbon) and EN 1.4301 (stainless), exposed to high temperatures. For this purpose, different heating temperatures (450, 800 and 1150 °C) and two types of cooling (rapid in water and slow at room temperature) were used. Mass loss and tensile strength were evaluated, and the ductility indices of these steels were analysed in detail, accompanied by a discussion with a statistical analysis and fractography. The results indicate that stainless steel performs better than carbon steel in a fire. The B500SD reinforcement exhibited a decrease in yield strength of up to 239 MPa (↓ 55%) compared to the reference specimen when heated to 1150 °C. Additionally, it has been observed that rapid cooling results in a more pronounced decrease in ductility in B500SD steel. However, slow cooling led to an increase in ductility in the three indices studied (Cosenza, Creazza and Ortega), with the presence of micro-void coalescence in the fractography corroborating the results. Thus, this research holds great practical interest in decision-making for the selection of structural materials, as it assesses the physical–mechanical behaviour of reinforced concrete after exposure to high temperatures. Full article

Hexafluoroethane and 1,1,1,3,3,3-hexafluoropropane (abbreviated as HFC-236fa and R-116, respectively, referred to as C₂F₆ and C₃H₂F₆ based on their molecular formulas) were selected as the object to study the corrosion effects of gas fire-extinguishing agents on different metal materials in the storage state. Typical metal materials used in storage containers including 304 stainless steel, Q235 carbon steel, 6061 aluminum alloy, H59 brass, and T2 copper were subjected to full-immersion corrosion experiments under simulated storage conditions with high-pressure and alternating high–low temperature cycles. High-definition cameras, a scanning electron microscope (SEM), high-precision electronic balances, an energy-dispersive spectrometer (EDS), and X-ray photoelectron spectroscopy (XPS) were used to explore the corrosion characteristics. The chemical reactions and mechanisms were analyzed. The results indicate the following: (1) A thin corrosion layer appears on the surface of the metal with varying degrees of severity but low prevalence. (2) The corrosion rates of C₂F₆ and C₃H₂F₆ were comparable and varied in the following order: 6061 aluminum alloy > Q235 carbon steel > H59 brass > 304 stainless steel > T2 copper. (3) C₃H₂F₆ is slightly higher than C₂F₆ in all corrosion rate values. (4) The corrosion of metal materials is mainly attributed to the reaction between metal elements and the F-containing groups produced by the cleavage of C₂F₆ and C₃H₂F₆. The generated metal halides in turn catalyze the cleavage of C₂F₆ and C₃H₂F₆. This catalytic effect may be positively correlated with the reactivity of the metal element. (5) The higher corrosive activity of C₃H₂F₆ compared to C₂F₆ is attributed to the ease of C–C bond cleavage, catalyzed by metal halogens. This study provides theoretical insights into the corrosion ability of halogenated alternatives as a replacement for halon-based fire extinguishers. Full article

Fire safety is a crucial issue for buildings, especially with the rise of modular construction, which demands materials that combine lightness with mechanical performance and stability. This study investigates a new concept for single-story modular constructions, made up of 3D cells assembled from thermally and acoustically pre-insulated concrete panels. These panels comprising four walls and two slabs forming the module, are stiffened, with thicknesses of only 5 cm for the walls and 7 cm for the slabs. Their constituent material is a self-compacting, high-volume steel-fiber concrete, containing 80 kg/m³ of steel fibers and 0.3 kg/m³ of polypropylene fibers. Experimental tests on a full-scale wall and slab revealed that adding 0.3 kg/m³ of polypropylene fibers effectively prevents concrete from splintering and achieves the necessary 30 min fire resistance. Standardized full-scale fire tests on walls and slabs confirmed that these thin structures meet fire resistance, insulation, and airtightness standards. The high volume of steel fibers provides ductility, maintaining structural integrity despite concrete spalling. The maximum spalling depth observed in some areas ranged 35 to 50 mm, without compromising structural performance. Overall, the modular system satisfies the fire safety requirements for structural stability (no collapse) and performance in single-story modular construction. Full article

Forest sub-surface fires represent a challenging combustion phenomenon to control, and the process of smoldering is often overlooked in wildfire incidents. Traditional forest fire research has prioritized flaming combustion over smoldering dynamics, despite its critical risk factors including sustained high temperature and ground surface collapse that significantly endanger firefighter safety. This study focuses on The Daxing’an Mountains, a prime sub-surface fire-prone region in China, employing field investigations and controlled smoldering experiments to quantify the key risk factors for sub-surface fires suppression while elucidating moisture content’s regulatory effects. The results demonstrate that sub-surface smoldering fires maintain elevated temperatures with the surface peak temperature reaching 600.24 °C and sub-surface peak temperature up to 710.70 °C. The spread rate is relatively slow (maximum 27.00 cm/h), yet exhibits pronounced fluctuations along the vertical profile, creating a critical predisposition to overhanging collapse. The moisture content has extremely significant effects (p < 0.01) on key risk factors including surface temperature, sub-surface temperature, collapse time and ignition duration. Lower moisture content prompted earlier surface collapses, whereas higher moisture content displays delayed collapse but resulted in dangerously elevated temperatures at collapse points, presenting extreme suppression risks. Full article

Current coal mine fire risk assessments often rely on static models and isolated factors, failing to capture the complex, dynamic interactions that lead to fires. To address this gap, we propose a comprehensive framework—termed INK-FBSD—integrating Interpretive Structural Modeling (ISM), the NK model, fuzzy Bayesian network analysis, and System Dynamics (SD) simulation. Using ISM, we identified and hierarchically structured 31 risk factors across human, equipment, environment, management, and fire protection domains, revealing that a robust mine safety accountability system is a pivotal root factor. The NK model quantifies how accident likelihood escalates as more factors interact—for example, four-factor couplings (e.g., equipment–environment–management–fire protection) yield significantly higher risk indices (T ≈ 0.34) than two-factor scenarios. The fuzzy Bayesian analysis estimates an overall 46% probability of a fire accident under current conditions, and diagnostic inference pinpoints excessive coal dust accumulation and neglected fire prevention as top contributors when an incident occurs (posterior probabilities 83% and 78%, respectively). Finally, SD simulations show how key risk factors (such as equipment failure and maintenance delays) can rapidly elevate to severe risk levels within 9–15 months without intervention, underscoring the need for continuous monitoring and proactive control. In summary, the INK-FBSD approach provides a multidimensional understanding of coal mine fire mechanisms and delivers practical guidance for safety management by prioritizing critical risk factors, anticipating high-risk coupling pathways, and informing more effective fire prevention and emergency response strategies. Full article

Safe evacuation in high-occupancy buildings during extreme disaster events is a complex systems problem involving dynamic interactions among multiple factors. Conventional static evaluation methods, however, are limited in capturing the underlying evolution mechanisms. To address this gap, this study develops an integrated framework that combines static multi-criteria evaluation with dynamic evacuation simulation. From a “human–facility–environment” perspective, a multidimensional indicator system is established, encompassing building physical features, equipment configuration, and management performance. The entropy weight method is employed to objectively determine indicator weights, and the TOPSIS method is applied to conduct a comprehensive static assessment. On this basis, BIM and Pathfinder are used to perform microscopic evacuation simulations, and the dynamic performance data obtained are fed back into the evaluation system to verify and adjust the static results. The results show that dynamic simulation not only validates the reliability of the static evaluation but also uncovers nonlinear mechanisms and coupling effects among safety indicators during evacuation. By integrating digital simulation techniques with multi-criteria decision-making methods, this study improves the scientific rigor of safety evaluation and provides new insights for research and practice in building safety. Full article

With the continuous development of the times and the natural gas industry, the number of composite laying between natural gas pipelines and power channels has increased. Once a gas pipeline leaks, it is easy to enter the power channel and cause serious explosion accidents. This article uses ANSYS/Fluent numerical simulation software to establish a composite laying model for buried gas pipelines and conducts numerical simulation research on gas pipeline leakage, obtaining the leakage laws of gas under different pressure levels, leakage hole diameters, and soil types. The results show that the concentration of gas and leakage entering the power channel increases linearly with the increase in pressure. However, as the pressure continues to increase, the impact on diffusion weakens. It has been demonstrated that an increase in the diameter of the leakage hole results in accelerated diffusion, leading to an increased diffusion rate into the power channel. It is evident that the magnitude of the viscous resistance coefficient and inertial resistance coefficient of the soil directly correlates with the ease with which gas can diffuse within the soil. Full article

As the demand for maritime transportation of power battery shipping containers grows rapidly, the incidence of fire accidents has increased in tandem. However, most studies focus on analyzing fire causes through the thermal runaway mechanism; few analyze fire risk across the full maritime transportation process from a safety science perspective. To fill this gap, based on the thermal runaway mechanism of lithium-ion batteries, this study couples the loading characteristics of shipping containers with maritime operating conditions and employs the Fault Tree (FT) model, Bayesian Network (BN) model, and Attack–Defense Game Theory for investigation. The results are as follows: Starting from three core factors—battery thermal runaway mechanism, scenario characteristics of shipping container maritime transportation, and failure of initial emergency response—and combining the FT model, it qualitatively identified and systematically sorted accident-causing factors. Via the FT-BN conversion criteria and expert assessment results, the fire probability of po’wer battery shipping containers on the target route was calculated to be 35%. According to Attack–Defense Game Theory, two key risk evolution pathways were identified with occurrence probabilities of 3.77% and 4.35%, respectively. Meanwhile, their action mechanisms were elaborated on, and the targeted preventive measures were proposed. This study provides theoretical support and methodological reference for the systematic assessment of fire risks associated with power battery shipping containers in maritime scenarios. Full article

Fluorine-free foams (FFFs) have been introduced as alternatives to aqueous film-forming foams (AFFFs), which are based on per- and polyfluoroalkyl substances (PFASs). However, adoption of FFFs remains limited due to the lack of universal drop-in replacements and limited data on their health and environmental impacts. This study examined incentives and barriers to implementing FFFs in Fire Training Facilities (FTFs) to support the transition away from PFAS-based products. A survey was conducted from September 2022 to December 2023 across the U.S. and Canadian FTFs, including state-funded facilities, metropolitan fire departments, airports, military, and industrial brigades. Developed in partnership with fire service organizations, the survey assessed current foam use, motivations for transition, and associated challenges. Of all FTF training with Class B foams, 38% reported using FFF products. Primary incentives included environmental and health concerns, safety, and regulatory pressures. Key challenges were transition costs, training requirements, and uncertainties around disposal of foams. These findings highlight that while momentum toward FFF adoption is evident, ensuring products are genuinely PFAS-free and providing comprehensive training will be critical for effective, large-scale implementation. Fire training facilities can play a pivotal role in guiding this transition. Full article