Search Results (219)

In recent years, the energy revolution has driven the rapid development of lithium-ion batteries (LIBs). A fire suppression system capable of rapidly and effectively extinguishing LIB fires constitutes the last line of defense for ensuring the safe operation of the LIB industry. In this study, an experimental platform simulating the storage environment of LIBs in energy-storage stations was constructed, and liquid nitrogen (LN) was employed to conduct fire suppression tests on LIBs. The effective utilization of 17.4 kg of LN during the suppression process inside the battery module was quantified. In addition, fire compartments were established within the battery module, and a strategy for enhancing the LN suppression effectiveness was proposed. The results indicate that, without intervention, the thermal runaway propagation (TRP) rate within the LIB module gradually accelerates. After LN injection, the effective utilization of LN for extinguishing individual LIBs decreases progressively along the sequence of TRP. Creating fire compartments inside the PACK using 6 mm aerogel blankets effectively reduces the transfer of energy from the region undergoing thermal runaway (TR) to other regions, while simultaneously enhancing the extinguishing performance of LN. Under the same LN dosage, the introduction of fire compartments increases the effective utilization from 0.037 to 0.051. However, as the compartment volume decreases, the degree of improvement in LN utilization is reduced. This work is expected to provide guidance for the engineering application of LN-based fire suppression systems to inhibit LIB TR and its propagation. Full article

A growing number of fires and explosions in energy storage plants have been triggered by the thermal runaway of lithium-ion batteries. Owing to the complex physicochemical properties of these batteries, their fire safety issues remain unresolved and constitute a major obstacle to the large-scale deployment of energy storage systems. Compared with conventional extinguishing media, liquid nitrogen (LN₂) offers a dual suppression mechanism, i.e., rapid endothermic vaporization and oxygen displacement by inert nitrogen gas, making it highly suitable for lithium-ion battery fire control. However, the key operational parameters governing its suppression efficiency remain unclear, leading to excessive or insufficient LN₂ use in practice. This study established a dedicated experimental platform and designed 10 experimental conditions, each repeated three times, to investigate the propagation of thermal runaway between adjacent batteries and to quantify the suppression performance of LN₂ under varying nozzle diameters and injection strategies. Results demonstrate that under identical injection pressures, larger nozzle diameters significantly outperform smaller ones in cooling and suppression efficiency. The optimal nozzle diameter was found to be 14 mm, achieving a cooling efficiency of 40%. Furthermore, intermittent LN₂ injection of equal total mass outperformed continuous injection, with a 45 s intermittent duration achieving a cooling efficiency of 63%, 23% higher than continuous injection. These findings provide quantitative guidance for the design of LN₂-based suppression systems in large-scale lithium-ion battery energy storage modules. Full article

Elderly welfare institutions in Taiwan have experienced multiple severe fire incidents, with smoke inhalation accounting for the majority of fatalities. Hot smoke can rapidly propagate through interconnected ceiling spaces, complicating evacuation for residents with limited mobility who depend heavily on caregiving staff and external responders. Field inspections conducted in this study indicate that 82% of residents require assisted evacuation, underscoring the critical role of early detection, staff-mediated response, and effective smoke control. Drawing on disaster management theory, this study examines key determinants of fire safety performance in elderly welfare institutions, where caregiving staff are primarily trained in medical care rather than fire safety. A total of 64 licensed institutions in Tainan City were investigated through on-site inspections, structured checklist-based surveys, and statistical analyses of fire protection systems. In addition, a comparative review of building and fire safety regulations in Taiwan, the United States, Japan, and China was conducted to contextualize the findings. Using the defense-in-depth framework, this study proposes a three-layer fire safety strategy comprising (1) prevention of fire occurrence, (2) rapid fire detection and early suppression, and (3) containment of fire and smoke spread. From a sustainability perspective, this study conceptualizes fire safety in elderly welfare institutions as a problem of risk governance, illustrating how defense-in-depth can be operationalized as a governance-oriented framework for managing fire and smoke risks, safeguarding vulnerable older adults, and sustaining the resilience and continuity of long-term care systems in an aging society. Full article

This study investigates the fire behaviour of Battery Electric Vehicles (BEVs) and Internal Combustion Engine Vehicles (ICEVs) in confined environments such as underground parking facilities and tunnels. Using the Fire Dynamics Simulator (FDS), several scenarios were modelled to analyse the effects of ventilation and automatic suppression systems on fire growth, heat release, and smoke propagation. Three ventilation configurations—reduced, standard, and increased airflow—were evaluated to determine their influence on combustion dynamics and thermal development. Results show that BEV fires produce higher peak Heat Release Rates (up to 7 MW) and longer combustion durations than ICEVs, mainly due to self-sustained battery reactions. Increased ventilation enhances smoke removal but intensifies flames and radiant heat transfer, while limited airflow restricts combustion yet leads to hazardous smoke accumulation. The inclusion of a sprinkler system effectively reduced temperatures by over 60% within 100 s of activation, though residual heat in BEVs poses a risk of re-ignition. This underlines the need for tailored ventilation and suppression strategies in modern underground facilities to ensure safety in the transition toward electric mobility. Full article

Wildfires pose a growing global threat, demanding rapid, scalable, and autonomous response strategies. This study proposes HG-MADQN (Heuristic-Guided Multi-Agent Deep Q-Network), a hybrid framework that integrates reinforcement learning with biologically inspired pheromone-based heuristics to achieve adaptive fire detection and suppression using drone swarms. The system models a decentralized swarm operating in a grid-based environment, where each drone combines learned policies with heuristic guidance derived from a dual-pheromone mechanism (a fire-attraction field guiding suppression and a coverage-repulsion field promoting exploration). The proposed hybrid approach ensures efficient coordination, minimizes redundant movements, and maintains continuous area coverage without centralized control. Simulation experiments conducted on dynamic wildfire scenarios demonstrate that HG-MADQN significantly outperforms traditional heuristic, Lévy-Flight, and reinforcement learning (MADQN) algorithms. It achieves faster containment, reduced burned area, and lower resource consumption, while exhibiting strong robustness across multiple swarm sizes and fire configurations. The results confirm that hybridizing learned and heuristic decision models enables a balanced exploration–exploitation trade-off, leading to improved scalability and resilience in cooperative fire suppression missions. Full article

This review surveys the recent literature on the fire resistance of reinforced concrete (RC) columns based on a bibliometric analysis of publications to reveal research trends and focus areas. The collected studies are synthesized from the perspectives of materials, structural behaviors, parameter influences, and predictive modeling. From the material aspect, the review summarizes the degradation mechanisms of conventional concrete at elevated temperatures and highlights the improved performance of ultra-high-performance concrete (UHPC) and reactive powder concrete (RPC), where dense microstructures and fiber bridging effectively suppress spalling and help maintain residual capacity. In terms of structural behavior, experimental and numerical studies on RC columns under fire are reviewed to clarify the deformation, failure modes, and effects of axial load ratio, slenderness, cover thickness, reinforcement ratio, boundary restraint, and load eccentricity on fire endurance. Parametric analyses addressing the influence of these factors, as well as the heating–cooling history, on overall stability and post-fire performance is discussed. Recent advances in thermomechanical finite element analysis and the integration of data-driven approaches such as machine learning have been summarized for evaluating and predicting fire performance. Future directions are outlined, emphasizing the need for standardized parameters for fiber-reinforced systems, a combination of multi-scale numerical and machine-learning models, and further exploration of multi-hazard coupling, durability, and digital-twin-based monitoring to support next-generation performance-based fire design. Full article

Acoustic fire suppression is a novel and environmentally friendly fire-extinguishing method. Electrical wires, as an important material in electrical systems, are a major cause of fires when short-circuited. In this study, we conducted experimental research on the flame spread and extinguishing characteristics of polyethylene-insulated electrical wires under the action of transverse acoustic waves within a frequency range of 50–70 Hz. The study systematically investigated the changes in flame morphology during the spreading process under different acoustic wave conditions. It was found that the flame spread rate first decreases and then increases with the increase in sound pressure, and the higher the acoustic frequency, the higher the spread rate. This study focused on the effect of acoustic frequency and wire inclination angle (0°, 30°, 60°) on the critical sound pressure for flame extinction. The experimental results showed that the critical sound pressure for flame extinction increases with the increase in frequency and inclination angle, with measured values ranging from 0.11 to 0.36 Pa for horizontal wires. An empirical model for predicting the critical sound pressure of flame extinguishment of inclined wires under acoustic waves was established based on an analysis of the strain rate. Full article

Frequent crude oil spills during offshore oil and gas production and transportation have inflicted irreversible detrimental effects on both human activities and marine ecosystems; with particular risks of secondary disasters such as combustion and explosions. To address these challenges; advanced oil sorption technologies have been developed to overcome the inherent limitations of conventional remediation methods. In this study, a flame-retardant protective coating was fabricated on melamine sponge (MS) through precipitation polymerization of octa-aminopropyl polyhedral oligomeric silsesquioxane (POSS) and hexachlorocyclotriphosphazene (HCCP), endowing the MS@PPOS-PDMS-Si composite with exceptional char-forming capability. Secondary functional layer: By coupling the complementary physicochemical properties of polydimethylsiloxane (PDMS) and SiO₂ nanofibers, we enabled them to function jointly, achieving superior performance in the material systems; this conferred enhanced hydrophobicity and structural stability to the MS matrix. Characterization results demonstrated a progressive reduction in peak heat release rate (PHRR) from 137.66 kW/m² to118.35 kW/m², 91.92 kW/m², and ultimately 46.23 kW/m², accompanied by a decrease in total smoke production (TSP) from 1.62 m² to 0.76 m², indicating significant smoke suppression. Furthermore, the water contact angle (WCA) exhibited substantial improvement from 0° (superhydrophilic) to 140.7° (highly hydrophobic). Cyclic sorption–desorption testing revealed maintained oil–water separation efficiency exceeding 95% after 10 operational cycles. These findings position the MS@PPOS-PDMS-Si composite as a promising candidate for emergency oil spill response and marine pollution remediation applications, demonstrating superior performance in fire safety, environmental durability, and operational reusability. 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

Thermal runaway (TR) in lithium-ion batteries presents a significant safety hazard for electric vehicles (EVs), often resulting in fire or explosion. Mitigating TR requires thermal-protection strategies capable of delaying or suppressing heat propagation within battery pack cases (BPCs). This study proposes a flame-retardant BPC design and evaluates its effectiveness through a combined approach using CFD-based thermal analysis and multiscale experimental validation. In the CFD model, a heat-source temperature of 1107 °C was applied to simulate the thermal load during TR, together with a coolant flow rate of 17 L/min. Material-level verification was conducted through high temperature specimen tests, in which flame-retardant pads were heated to a target of 1100 °C with an allowable tolerance of ±10% for 5 min; the unheated (backside) temperature remained below 160 °C. Full-scale assessment involved heating the BPC upper case at temperatures exceeding 500 °C for 10 min, where the backside temperature remained below 150 °C. Module-level TR experiments further confirmed that the flame-retardant layer reduced the external temperature from 240–260 °C to below 150 °C. The results demonstrate that the proposed design effectively delays thermal penetration and maintains external safety thresholds, offering practical guidelines for developing safer EV battery systems. 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

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

This study investigated spruce wood (Picea abies Karst. L.) dust generated during sanding in a woodworking company, focusing on its health, explosion, and fire hazards. Microscopic analyses revealed that dust particles ranged from 2.38 μm × 1.69 μm to 499.71 μm × 403.30 μm, with an average size of 73.2 μm × 37.98 μm. Smaller particles exhibited a spherical morphology, while larger ones were elongated and fibrous. Sieve analysis confirmed that particles sized 63–75 μm formed the largest fraction (46.74%), with 71% of the total dust being airborne (<100 μm), including 5% PM₁₀ and 1% PM_2.5. Explosion tests identified a lower explosion limit (LEL) of 80 g·m⁻³, with dust classified as highly explosive (ST 2). Smaller particles were found to significantly reduce the LEL, increasing explosion susceptibility. These findings highlight the dual risk of inhalation exposure and explosion potential. Practical safety recommendations include ensuring efficient local dust extraction, mandatory use of respiratory protection, and restricted worker movement near sanders. Furthermore, organizational measures aligned with ATEX standards—such as daily cleaning, removal of settled dust layers, use of explosion-safe industrial vacuum cleaners, and installation of automatic explosion suppression systems in extraction units—are essential. Full article

This paper constructs a numerical simulation model for the fire and fire-fighting system of an all-electric vehicle ro-ro passenger ship to study the influence of fire characteristics and fire-fighting system layout parameters on the fire-extinguishing system. The simulation results show that the fire can spread to the upper deck within 52 s, and the smoke will fill the main deck within 57 s. The study found that the battery capacity has a super-linear relationship with the fire hazard, and the fire thermal spread radius of a 240 Ah battery can reach 3.5 m. The high-expansion foam system has a low applicability in quickly suppressing battery fires due to its response delay and limited cooling capacity for deep-seated fires; the fire-extinguishing efficiency of fine water mist has spatial dependence: 800 µm droplets achieve effective cooling in the core area of the fire source with stronger penetrating power, while 200 µm droplets show better environmental cooling ability in the surrounding area; at the same time, the large-angle nozzles with an angle of 80–120° have a wider coverage range and perform better in overall temperature control and smoke containment than small-angle nozzles. The study also verified the effectiveness of fire curtains in forming fire compartments through physical isolation, which can reduce the heat radiation range by approximately 3 m. This research provides an innovative solution for improving the fire safety level of transporting all-electric vehicles on ro-ro passenger ships. Full article

Guizhou Province in China exhibits a distinctive agroforestry mosaic landscape with frequent human activity in forested areas. This region experiences recurrent forest fires, characterized by significant difficulties in suppression and high risks. Research on the prediction of forest fire occurrences holds crucial practical significance in terms of enhancing regional forest fire prevention capabilities. However, the current fire risk forecasting methods in the area consider only meteorological factors, neglecting firebrands and fuel conditions, which results in deviations between forecasted and actual fire occurrences. Therefore, this study proposes a novel fire occurrence prediction method that utilizes the ignition component (IC) from the National Fire Danger Rating System (NFDRS) to characterize the weather–fuel complex while integrating the firebrand occurrence probability to construct a predictive model. The applicability and accuracy of this method are also evaluated. The results show that, firstly, the probability of at least one daily forest fire occurrence in the study area can be expressed as a nonlinear function based on the IC. Secondly, as time progresses, the correlation between the forest fire occurrence probability and the IC shows a decreasing trend, although the differences across different time spans are not statistically significant. Thirdly, when a 5-year time span is adopted, the error in calculating the forest fire occurrence probability based on the IC is significantly lower than at other time spans. Finally, a predictive model for the forest fire occurrence probability based on the IC is established, where P = (100*IC)/(4.06 + IC), with a mean absolute error (MAE) of 4.83% and mean relative error (MRE) of 14.87%. Based on this research, the IC enables the calculation of forest fire occurrence probabilities, assessment of fire risk ratings, and guidance for fire preparedness and planning. This work also provides theoretical support and a methodological reference for conducting forest fire probability studies in other regions. Full article