Search Results (50)

Utility tunnels concentrate various important urban engineering pipelines within a shared underground space, which poses significant fire risks, particularly from cable fires. In this study, a full-scale fire experiment was conducted to investigate the temperature distribution characteristics of cable fires in utility tunnels, along with the effects of spray intensity, cable fullness, and longitudinal ventilation on the extinguishing efficiency of a high-pressure water mist fire extinguishing system (HWMFES). The results show that the maximum heating area of a cable fire in a utility tunnel is localized to the three cable trays nearest to and directly above the fire source, with a peak temperature of 825 °C, while the impact on other areas is negligible. Increasing the spray intensity from 0.7 to 1.0 L/(min·m²) reduced the time required to lower temperatures to 50 °C by 40.8%, while reducing cable fullness from 12 to 6 cables per tray shortened extinguishing time by 22.5%. Additionally, applying a ventilation speed of 2 m/s enhanced cooling efficiency, reducing the time to reach 50 °C by 67.5% compared to still air conditions. These findings provide practical insights and data support for optimizing the design and application of HWMFES in enhancing fire safety in utility tunnels. Full article

The transition to electric mobility has intensified efforts to develop battery technologies that are not only high-performing but also environmentally sustainable. A critical element in battery system design is the structural housing, which must provide effective impact protection to ensure passenger safety and prevent catastrophic failures. This study examines the impact response of an innovative sheet molding compound (SMC) composite battery housing, manufactured from an Elium resin modified with Martinal ATH matrix, reinforced with glass fibers, that combines fire resistance and recyclability, unlike conventional thermoset and metallic housings. The material was characterized through standardized mechanical tests, and its impact performance was evaluated via drop-weight experiments on plates and a full-scale housing. The impact tests were conducted at varying energy levels to induce barely visible impact damage (BVID) and visible impact damage (VID). A finite element model was developed in LS-DYNA using the experimentally derived material properties and was validated against the impact tests. Parametric simulations of ground and pole collisions revealed the critical velocity thresholds at which housing deformation begins to affect the first battery cells, while lower-energy impacts were absorbed without compromising the pack. The study provides one of the first combined experimental and numerical assessments of Elium SMC in battery enclosures, emphasizing its potential as a sustainable alternative for next-generation battery systems for transport applications. Full article

Sandwich panels, widely used in factory and warehouse construction, are highly susceptible to fire due to their fragile surfaces and polyurethane-insulated cores. Such structures facilitate rapid fire spread, significantly increasing the risk of extensive thermal damage. Although conventional measures, such as surface pre-wetting, are commonly utilized, their effectiveness is limited due to rapid evaporation. To address this issue, the current study evaluates the effectiveness of compressed air foam (CAF) applied as a pre-application treatment for delaying fire spread. Full-scale fire experiments were conducted to measure temperature variations across sandwich panel surfaces treated under three different conditions: untreated, water-treated, and CAF-treated. Experimental results indicated that CAF effectively formed a stable insulating barrier, maintaining temperatures well below critical thresholds, compared to untreated and water-treated panels. CAF application demonstrated superior thermal protection, reducing internal temperatures by up to 78% compared to untreated conditions and by 67.5% compared to water-treated conditions. These findings underscore the practical importance of adopting CAF pre-application as a proactive fire mitigation strategy, significantly enhancing fire safety standards in industrial and storage facilities constructed with sandwich panels. Full article

This study proposes an equivalent furniture fire model based on standard combustible assembly and verifies its feasibility as a substitute for real furniture through full-scale experiments and numerical simulations. Experiments show that the peak heat release rate and total heat release of the standard combustible assembly are highly consistent with those of the single-seat sofa. The numerical model has been verified by experimental data. The dynamic characteristics of the heat release rate (HRR) curve are consistent with the temperature evolution process, confirming its reliability for the numerical model. The research on optimizing fire extinguishing parameters is carried out based on this numerical simulation. The results show that the response time of the horizontal sprinkler is 22 s shorter than that of the vertical sprinkler, and the fire extinguishing efficiency is improved. Reducing the sprinkler height to 3 m can accelerate activation and reduce CO₂ release. A flow rate of 91.4 L/min can effectively control the fire, but when it exceeds 150 L/min, the fire extinguishing efficiency is significantly reduced. The low response time index sprinkler starts up 88 s faster than the standard type, significantly enhancing the initial fire suppression capability. This scheme provides a safe, economical, and repeatable standardized combustible assembly for fire training and offers theoretical support for the parameter design of intelligent fire extinguishing systems. Full article

The emergence of electric vehicles (EVs) has brought specific risks, including the possibility of fires or explosions resulting from mechanical, thermal, or electrical failures, which can lead to thermal runaway (TR). There is a great lack of knowledge about how to act safely in this type of fire. This study carried out two full-scale fire experiments on electric vehicles to investigate response strategies to electric vehicle fires caused by thermal runaway. Centro Zaragoza provided technical advice for these tests, so that they could be carried out safely, controlling the risks. This advice has allowed Centro Zaragoza to analyze different response strategies to the fires in electric vehicles caused by thermal runaway. On the other hand, the propagation patterns of thermal runaway fires in electric vehicles were investigated. The early-phase effectiveness of fire blankets and other extinguishing measures was tested, and the temperature distributions inside the vehicle and the type of fire generated were measured. The results showed that fire blankets successfully extinguished flames by cutting off the oxygen supply. These findings contribute to the development of effective strategies for responding to electric vehicle fires, enabling the establishment of good practice for fire suppression in electric vehicles and their batteries. Full article

To enhance the fire safety protection level of deeply buried metro stations, this study conducted full-scale fire experiments based on Wulichong Station of Guiyang Metro Line 3. It systematically investigated the laws of smoke movement and temperature distribution under the coupled effects of different fire source powers and smoke extraction system states. Through the set up of multiple sets of comparative test conditions, the study focused on analyzing the influence mechanism of the operation (on/off) of the smoke extraction system on smoke spread characteristics and temperature field distribution. The results indicate that under the condition where the smoke extraction system is turned off, the smoke exhibits typical stratified spread characteristics driven by thermal buoyancy, with the temperature rising significantly as the vertical height increases. When the smoke extraction system is activated, the horizontal airflow generated by mechanical smoke extraction significantly alters the flame morphology (with an inclination angle exceeding 45°), effectively extracting and discharging the hot smoke and leading to a more uniform temperature distribution within the space. Full article

Assessments of subway train fires were conducted based on full-scale experiments and numerical simulations. The experimental platform and simulation model were established according to a real subway train in China. The results show that there was no obvious flame spread, and all the electrical circuitry maintained its integrity during a standard luggage fire. The maximum HRR (heat release rate) of the luggage fire obtained through the full-scale experiment was 155.5 kW, which was almost the same as the standard HRR curve provided in EN 45545-1. However, the fire only lasted approximately 180 s, which was much shorter than a standard fire (600 s). Through numerical simulations of an entire subway train, the side wall and roof ignited quickly, and the fire continually spread to the adjacent compartment under the extreme scenario with a gasoline pool fire and exposed winterproof material. The maximum HRRs of the luggage and gasoline pool fires were 179.7 and 17,800.0 kW, respectively. According to the experimental and simulation results, the Duggan method, which assumes that all combustibles inside a train compartment burn at the same time, was not appropriate for assessing the fires in the subway train, and a simple revised frame was proposed instead. Full article

This study deals with the simulation of office fires by combining large-scale experiments with nine wooden cribs and a carefully calibrated computer model. It shows how real fire conditions, reaching up to 800–1000 °C, could be reproduced experimentally. The numerical model was validated by comparing HRR and temperature data with real measurements. Accuracy was assessed using error metrics to ensure that the simulation closely approximates real fire behavior. The method of determining HRR through mass loss has been used in prior studies, but those typically involved small-scale setups and limited fire loads. Unlike most approaches in the field, this research is based on a full-scale experiment involving nine wooden cribs, offering superior realism and thermal intensity. The experimental data—temperature evolution, HRR, and observed destructive effects—were used to calibrate the FDS model. The strength of the study lies in the repeatability and accuracy of the simulation, its practical relevance, and its potential to improve fire safety evaluations for office spaces. Full article

This study presents a novel water mist fire fighting system that integrates water mist sprays and water mist curtains, designed to achieve simultaneous fire suppression, thermal insulation, and smoke control. Three full-scale experiments were conducted under various fire scenarios, and the changes in fire behavior and heat release rate were examined to evaluate the effectiveness of the water mist system in extinguishing fires. Additionally, the spatiotemporal changes in ceiling temperature were monitored to assess the cooling and protective effects of the water mist. The thermal insulation capability of the system was also investigated by detecting the temperature distribution inside the tunnel. Moreover, the smoke conditions upstream and downstream of the tunnel were analyzed to evaluate the smoke-blocking performance of the water mist system. The findings demonstrate that the water mist fire fighting system is highly efficient in attenuating the fire and restricting its progression. Within the water mist spray section, the average ceiling temperature decreased exponentially during both the initial and steady burning phases across all tested fire scenarios. Nonetheless, the smoke-carrying capacity of the water mist spray is limited. Fortunately, the dispersed smoke was diluted by water mist, markedly enhancing visibility and mitigating the impact of smoke on tunnel illumination. Full article

This study investigated a factory fire that resulted in an unusual situation that caused the deaths of two firefighters. The official fire investigation report was analyzed, records were obtained, and on-site investigations and interviews were conducted. Using these additional data and a calorimetric analysis to determine the combustibility of goods stored in the building at the time, a functional 3D model was produced, and a fire dynamics simulator (FDS) was run. The model was augmented using the results of calorimetric experiments for three types of primary goods being stored in the warehouse area: paper lunch boxes, tissue paper, and corrugated boxes. The reaction heat data obtained for each of the three sample types was 848.24, 468.29, and 301.21 J g⁻¹, respectively. The maximum mass loss data were 98.522, 84.439, and 90.811 mass% for each of the three types, respectively. A full-scale fire scene reconstruction confirmed the fire propagation routes and changes in fire hazard factors, such as indoor temperature, visibility, and carbon monoxide concentration. The FDS results were compared to the NIST recommended values for firefighter heat exposure time. The cause of death for both firefighters was also investigated in terms of the heat resistance of the facepiece lenses of their self-contained breathing apparatus. Based on the findings of this study, recommendations can be made to forestall the recurrence of similar events. Full article

In order to study the characteristics of the thermal runaway process of a full-size prefabricated cabin energy storage system, a full-scale prefabricated cabin energy storage physical fire test platform was designed using 100% SOC energy storage battery packs as the thermal runaway object, and full-scale prefabricated cabin energy storage system physical fire experiments were conducted. This experiment analyzes the early change rules of parameters such as temperature, voltage, CO, and VOC after the energy storage system enters thermal runaway and explores the technical methods to improve the fire protection of electrochemical energy storage systems. The results show that the time when the surface temperature of the runaway cell undergoes a sudden change is 37 s later than the time when the voltage undergoes a sudden change; the CO at the bottom and middle of the runaway cluster reaches the alarm threshold 25 s and 39 s earlier than that at the top of the cluster, respectively, and the peak concentration of CO at the bottom and middle of the cluster is more than three times that at the top of the cluster. The opening of the fan causes the CO concentration on the left side of the thermal runaway cluster to be higher than that of the runaway cluster; before the battery thermal runaway, the VOC concentration at the middle and top of the runaway cluster is generally higher than that at the bottom of the cluster. After thermal runaway occurs, the VOC concentration at the bottom of the thermal runaway cluster exceeds that at other positions of the runaway cluster and the adjacent cluster; the t_VOC at the top, middle, and bottom of the thermal runaway cluster is 2296 s, 1681 s, and 1464 s earlier than the t_CO, respectively, but the initial detection value of VOC fluctuates more than that of CO. Full article

Determining the appropriate position of a positive pressure ventilator, where it exhibits the highest efficiency (measured by the achieved volumetric flow rate), can influence the success of rescue operations conducted by fire protection units. The aim of this article is to evaluate the possibility of using LES (Large Eddy Simulation) analyses to verify the positioning parameters of positive pressure ventilators in numerical simulation conditions, without the need for time-consuming experiments. The article presents a comparative analysis of full-scale experimental studies (conducted on a test setup to assess the velocity profile of the air jet in open flow) and CFD numerical analyses. The analysis confirmed the convergence of the flow rate parameter entering the surface of the door opening model installed on the test setup. Depending on the distance of the ventilator position (1–7 m), a convergence degree ranging from 1.6% to 3.8% was achieved for the volumetric flow rate. This publication demonstrates that the LES model is a suitable tool for effectively determining the working positions of positive pressure ventilators, as defined in real working conditions (open flow). The analysis may serve as a helpful tool for manufacturers of mobile ventilators, who can use the method for the technological testing of their units without conducting time-consuming experiments. Full article

Controlling the simulated smoke flow field is important in the airworthiness verification experiment for the smoke detection system in aircraft cargo compartments to accurately replicate actual fire smoke. In existing studies, the unsteady adjustment performance of the actuator to the simulated smoke flow field has not been comprehensively evaluated, and the model-based closed-loop flow control method encounters the unmodeled dynamics of the complex turbulent flow field. To solve the aforementioned problems, this study first uses the system identification method to obtain transfer function models for different actuation modes. Moreover, the transient adjustment capabilities of different actuation modes for the simulated smoke flow field are thoroughly evaluated. Then, an adaptive flow control law based on a radial basis function neural network is designed based on the selected actuating mode. Furthermore, closed-loop control experiments based on the adaptive control law are performed. The root locus of the transfer functions for two different actuation modes are compared, which reveals that adjusting the flow rate of simulated smoke exhibits a better stability margin than the actuation mode that regulates the upward momentum of simulated smoke. The experimental results in a full-scale mock-up of an aircraft cargo compartment demonstrate that the designed control law realizes dynamic tracking control with the unsteady concentration of actual fire smoke as the control target. Compared with that of PID control, the root mean square error of the control system is reduced by more than 40%. The simulated smoke under the closed-loop control obtains a light-transmission response equivalent to that of the actual fire smoke within a 5% error margin. The proposed closed-loop adaptive flow control method for simulated smoke approximates the unsteady process of actual fire smoke. It provides technical support for the replacement of actual fire smoke in the airworthiness verification experiment of smoke detection in aircraft cargo compartments. Full article

A subway transfer station hall is crowded and complex in structure, which makes evacuation more difficult in case of a fire, but also provides more strategic options for smoke extraction. Full-scale experiments and numerical simulations are conducted to investigate the feasibility and performance of coordinated ventilation in a T-shaped transfer station hall, accounting for different fire source locations, ventilation modes, and fire shutter operations. It is found that the optimal ventilation strategy varies based on the fire location within the T-shaped configuration. For fires on the ‘T’s horizontal side, lateral airflow from longitudinal fans can effectively disrupt smoke spreading, with coordinated extraction strategies outperforming the traditional methods. However, for fires on the ‘T’s longitudinal side, horizontal fans are ineffective in controlling smoke flow, making the traditional fire shutter closure optimal. The idea of dispersing hot smoke to a reasonable degree can create better evacuation conditions for people near a fire, while creating almost no new danger zones. Full article

Nowadays, electromobility has a significant role in transportation; different electrically driven vehicles are spreading continuously. Due to this form of drivetrain, fire safety hazards have also changed when compared to those of conventional vehicles. Lately, electric vehicle fires have become more common; thus, we have chosen to investigate the negative impacts of these fires on humans and the environment, in addition to the toxic properties of the resulting combustion products. In our research work, we conducted a full-scale fire experiment on an electric passenger car. Fire extinguishing was executed with fire-fighting foam, and its efficiency was examined. After extinguishing the fire, we took samples from the combustion gases and soil. Samples were subjected to laboratory investigations. Our results and experiences are presented in this article. Full article