Vehicle Fire Research Articles

Study on the flame radiative heat transfer and near-field radiation heat flux predictive model of vehicle fires in a tunnel

As a major form of heat transfer, flame thermal radiation has an important effect on the ignition of adjacent energy, fire spread and environmental damage. Forecasting the flame radiation heat flux can provide theoretical basis for fire hazard assessment, fire extinguishing and salvation. Meanwhile, the distinctive structure of the arc tunnel can result in significant variations in the local heat and mass transfer processes during tunnel fires compared to those in rectangular tunnels, leading to different fire characteristics parameters. In this study, experiments and theoretical analyses were conducted to investigate the flame length scale and near-field radiation heat flux on the lower surface of an arc-shaped ceiling induced by vehicle fires in a tunnel. The findings reveal that the flame length scale in the transverse direction beneath the arc-shaped ceiling decreases with an increasing burner aspect ratio and increases with the increasing heat release rate. A dimensionless model of the flame length scale under the arced ceiling with various burner aspect ratios was proposed based on the amount of remaining unburned fuel after flame impingement and the buoyancy component along the arc-shaped ceiling. Simultaneously, radiative heat fluxes on the lower surface also increase with rising heat release rate. The flame geometry beneath the arc-shaped ceiling is assumed to be a combination of a cuboid and an arc plate model based on the actual flame length scale. Subsequently, the view factor, radiative fraction, and flame surface area are analyzed to predict the radiative heat fluxes on the lower surface. The predictions of the cuboid and arc plate flame model show good agreement with the current experimental data. This work presents a dimensionless correlation of the flame length scale and calculates the view factor between the target and the arc plate to predict the near-field radiative heat flux more accurately. This approach also facilitates the understanding of flame spreading behavior and thermal hazards impacted by arced ceiling.

Emergency control of firefighting vehicles based on distributed integer programming

Fire-related emergency vehicle scheduling has always been an important part of autonomous vehicle emergency management. To maintain the fire safety of buildings and reduce the transportation loss of emergency resources, this paper constructs a multi-objective integer planning model for fire emergency resource scheduling, which minimizes the time spent in the transportation of fire materials and considers the transportation needs of potential fire vehicles. The fixed-point iterative algorithm is realized and optimized, and distributed computing is adopted to improve the solving speed. In this paper, the comparison and simulation experiments with Branch and Bound, improved particle swarm optimization and other algorithms are carried out. The results show that the model and the algorithm can effectively deal with the fire emergency vehicle scheduling problem under different simulated fires and multiple fires occurring at the same time, and have certain advantages in numerical stability and convergence speed.

Trends in childhood leukemia incidence in urban countries and their relation to environmental factors, including space weather.

Leukemia is the most common cancer in children. Its incidence has been increasing worldwide since 1910th, suggesting the presence of common sources of the disease, most likely related to people's lifestyle and environment. Understanding the relationship between childhood leukemia and environmental conditions is critical to preventing the disease. This discussion article examines established potentially-carcinogenic environmental factors, such as vehicle emissions and fires, alongside space weather-related parameters like cosmic rays and the geomagnetic field. To discern the primary contributor, we analyze trends and annual variations in leukemia incidence among 0-14-year-olds in the United States, Canada, Australia, and Russia from 1990 to 2018. Comparisons are drawn with the number of vehicles (representing gasoline emissions) and fire-affected land areas (indicative of fire-related pollutants), with novel data for Russia introduced for the first time. While childhood leukemia incidence is rising in all countries under study, the rate of increase in Russia is twice that of other nations, possibly due to a delayed surge in the country's vehicle fleet compared to others. This trend in Russia may offer insights into past leukemia levels in the USA, Canada, and Australia. Our findings highlight vehicular emissions as the most substantial environmental hazard for children among the factors examined. We also advocate for the consideration of potential modulation of carcinogenic effects arising from variations in cosmic ray intensity, as well as the protective role of the geomagnetic field. To support the idea, we provide examples of potential space weather effects at both local and global scales. The additional analysis includes statistical data from 49 countries and underscores the significance of the magnetic field dip in the South Atlantic Anomaly in contributing to a peak in childhood leukemia incidence in Peru, Ecuador and Chile. We emphasize the importance of collectively assessing all potentially carcinogenic factors for the successful future predictions of childhood leukemia risk in each country.

Comparative study of traffic signal design using Webster and IRC method

In India, the growth of population plays an important role in increasing the congestion at intersections because every person uses a separate vehicle for movement due to this reason we know every day many people die in road accidents due to lack of traffic control system because all intersections are not well signalized. So, it is not possible to control the movement of vehicles by traffic police due to the increase in the number of vehicles at intersections. Therefore, all intersections should be well signalized and traffic signals are specially designed for the emergency vehicles like Ambulance, Fire vehicles because emergency vehicles face delay at intersections when traffic is at red light and it is very dangerous for our society. In this project, Design of traffic signals is done with the help of the Indian Road Congress (IRC) and Webster's method at Gajularamaram service road intersection. Traffic signals are a better option for effective transportation. Traffic signal systems are used to control the flow of vehicles with the help of traffic lights, where Many roads meet together and make a junction. Traffic volume studies are used to lay down mainly how many vehicles are moving on the road at a particular section during a particular time. Traffic signals are the best way to control vehicle movement at intersections without any accidents and conflicts.

Full-Scale Fire Extinguishing Experiments to Analyze the Adaptability of Firefighting Facilities for Electric Vehicle Fires in Underground Parking Lots

Recently, the number of electric vehicles (EVs) has rapidly increased owing to an increase in international environmental problems and domestic eco-friendly policies. With the increase in the number of EVs, the number of EV fires is also increasing. However, full-scale experiments for fire risk analysis or verification studies on the adaptability of present firefighting facilities are lacking , except for EV fire suppression experiments. In this study, to analyze the adaptability of firefighting facilities to EV fires in underground parking lots, fire extinguishing experiments on EV fires were conducted by considering the conditions of firefighting facilities applied to existing buildings. The first experiment simulated a current underground parking sprinkler system (pre-action system). In the second experiment, a lower sprinkler system was added to the upper sprinkler system. Experiment #1 confirmed that preventing the spread of thermal runaway in EV battery packs was difficult but blocking fire spread to adjacent vehicles was possible. Experiment #2 confirmed that thermal runaway occurred in approximately 50% of EV battery packs. These experiments concluded that fire spread to adjacent vehicles could be blocked by the spray from the upper sprinkler system.

Effect of urban street canyon aspect ratio on fire-induced air pollutants dispersion under cross wind

The incidence of vehicle fires in urban street canyons has continuously increased with the process of urban modernization. The dispersion and accumulation of fire-induced air pollutants seriously affect residents’ safety. The effects of the street canyon aspect ratio and fire source location on fire-induced air pollutants dispersion under cross wind were numerically investigated in the paper. The results show that the street canyon aspect ratio can affect flow patterns and vortex structure and then lead to different accumulation states of air pollutants. Smoke development can be divided into four different regimes according to cross wind velocity. The re-entrainment phenomenon occurs when the fire source is close to the windward building or in the center of the street, but it does not occur when the fire source is close to the leeward building. Smoke tends to accumulate in street canyons when the aspect ratio is smaller and the fire source is closer to the leeward building. The variation of critical velocity with the aspect ratio can be divided into three regions, i.e., initial linear growth region (0.5 ≤ W/H < 1), constant region (1 ≤ W/H ≤ 1.5), and second linear growth region (1.5 < W/H ≤ 2). The dimensionless critical velocity and critical Froude number are used to quantify the re-entrainment phenomenon in different fire scenarios, and prediction models are finally proposed. The main findings can provide a more detailed reference for urban layout and air pollution control to reduce fire-induced air pollutants.

СЕРВИС ПОЖАРНОЙ БЕЗОПАСНОСТИ ПО КРИТЕРИЯМ ТЕХНИЧЕСКОЙ ГОТОВНОСТИ МАШИН СПЕЦИАЛЬНОГО НАЗНАЧЕНИЯ

The issue of diagnosing the operational and technical readiness for emergency response to fire risks of special-purpose vehicles is considered according to the criteria for the acceptable efficiency of the functioning of power plants of fire vehicles under operating conditions. An original instrumental apparatus is proposed for the implementation of an intelligent diagnostic process, including a working mathematical and analytical model in the form of a system of multiple regression equations, which relates the efficiency indicators of fuel equipment adjustments (cyclic fuel supply gc nom, injection pressure Rinj, free section of nozzles µf avtr, injection advance angle inj) with a combination of quality parameters of the combustion process (exhaust gas smoke K, CH, NOx, CO2, CO), measured (controlled) by gas analyzers. The diagnostic method can be implemented according to a program by the on-board processor of a fire truck of 4–5 technological generations or using pre-prepared nomograms.

Experimental study and new-proposed characterization of burning rate and flame geometry of gasoline pool fires with different aspect ratios

This study investigated the burning rate and the flame geometry of gasoline pool fires under crosswinds in the context of bridge vehicle fires. A 1:4 scale bridge fire platform was established. A total of 45 fire experiments were conducted on 9 gasoline pool with 1–2.2 aspect ratios under 0–2 m/s cross-wind. The influence mechanism of aspect ratio n on the characteristic parameters of pool fires was investigated. The results showed that the burning rate of gasoline pool ranges from 0.028 kg‧m−2‧s−1 to 0.064 kg‧m−2‧s−1, which increases with wind speed and pool size. When the wind speed exceeds 1 m/s, the title angle of the flame on the windward side is greater than 45° and is less affected by pool size. The wall heat conduction at wind downstream increases with aspect ratio when placing the longer side facing to cross flow. The correction factor Fr·n can be used to describe the competition between the air entrainment and the buoyancy in gasoline pool fire. A general model based on aspect ratio is proposed to quantify the burning rate and flame tilt characteristics of gasoline fires. The reliability and applicability of the model are compared with the existing experimental data.

Study on fire characteristics of lithium battery of new energy vehicles in a tunnel

In order to explore fire safety of lithium battery of new energy vehicles in a tunnel, a numerical calculation model for lithium battery of new energy vehicle was established. This paper used eight heat release rate (HRR) for lithium battery of new energy vehicle calculation models, and conducted a series of simulation calculations to analyze and compare the fire development characteristics of fuel vehicles and new energy vehicles with different HRR in a tunnel. This paper investigated temperature distribution below the ceiling and smoke diffusion in a tunnel, as well as the distribution of CO2 and CO concentrations, to explore the spread of lithium battery of new energy vehicle fires in a tunnel. Then, the accuracy of the numerical simulation was verified through comparison with existing examples. The results showed that there is a correlation between the temperature distribution below the ceiling in a tunnel and the HRR of lithium battery of new energy vehicle fires, with higher HRR and higher temperature below the ceiling in a tunnel. In addition, the heat release of fuel vehicles in a tunnel is lower than that of lithium battery of new energy vehicles. The analysis of the ceiling temperature of new energy vehicles in tunnels after a fire showed that for different HRR, the temperature below the ceiling increases with the increase of HRR. In tunnel fires, lithium battery of new energy vehicles generate higher temperature, smoke, and CO emission concentrations than fuel vehicles. Therefore, the risk of fire for lithium battery of new energy vehicles in tunnels is higher than that of fuel vehicles, and their fire safety needs to be paid more attention.

METHODOLOGY FOR EXPERIMENTAL RESEARCH OF THE FIRE HAZARD OF POWER LITHIUM-ION BATTERIES OF ELECTRIC VEHICLES UNDER THE INFLUENCE OF A HEATING PANEL

Even though lithium-ion batteries (LIBs) are the subject of various tests and research at the production stage, there are no isolated cases of electric vehicle fires, and the development dynamics are unpredictable. The particular danger of such fires lies in the oxygen release during an irreversible exothermic reaction in LIBs, which creates new challenges for fire and rescue services when extinguishing such fires. The study aims to develop the main provisions of the methodology for experimental studies of electric vehicle power batteries in terms of fire hazards using an electric heating panel. The ultimate goal of the study is to determine the temperatures at which an irreversible exothermic reaction, the opening of ventilation holes, and the combustion (explosion) of electric vehicle power batteries begin, as well as the time parameters at which such processes occur. Taking into account the peculiarities of the occurrence and course of the irreversible exothermic reaction, we have developed a methodology, the essence of which is to determine the temperatures of the onset of the irreversible exothermic reaction of the electric vehicle power battery, the opening of ventilation holes, and the combustion (explosion) of electric vehicle power batteries, the combustion temperatures of ventilation gases, as well as the time parameters at which these processes occur, which may change during battery operation and not correspond to the declared parameters of the manufacturer. For this purpose, we exposed LIBs to thermal energy from an electric heating panel and recorded the temperature and time during which an irreversible exothermic reaction occurs from the moment of an internal short circuit to a fire or explosion. The use of the proposed methodology of experimental studies of the elements of power batteries of electric vehicles regarding the fire hazard of an electric heating panel will make it possible to determine the temperature limits of the occurrence of irreversible exothermic reactions in LIBs, as well as the time parameters under which these processes occur. Keywords: electric vehicle fire, irreversible exothermic reaction, lithium-ion battery.

Design fire scenarios for hazard assessment of modern battery electric and internal combustion engine passenger vehicles

Full-scale fire testing of battery electric (BEVs) and internal combustion engine (ICEVs) passenger vehicles has historically shown peak heat release rates (HRRs) ranging from 5–10 MW. However, the vehicles tested in these studies are smaller with less energy capacity than vehicles currently on the market. This paper presents a model to extrapolate data from full-scale vehicle fire tests to evaluate the fire hazard associated with larger passenger vehicles. The model is validated on 20 full-scale vehicle experiments in the public literature and is then used to develop conservatively bounding fire scenarios for vehicles representative of the current market environment. No significant difference was observed in the HRRs between the similarly sized ICEVs and BEVs in this work; however, the predicted HRRs for both vehicle types significantly exceeded existing design guidance. While the model may be shown to be overly conservative in future testing, it is validated using the data that currently exists, and points to an alarming trend in the fire protection industry, where the hazard posed by single passenger vehicles may exceed existing design guidance.

The Development of Automatic Sprinkler System Concepts for Maritime Vehicle Carriers

Closed ro-ro spaces on maritime vehicle carriers are usually protected by a total-flooding carbon dioxide system. Such systems have many benefits, for example that there are no residues that can adversely affect the protected objects (in this case thousands of vehicles) and the agent is electrically non-conductive. However, there could be a considerable time delay from the start of a fire until the carbon dioxide system is discharged. Experience has shown that this delay time can cause significant fire damage and jeopardize the performance of the system. Within the EU funded LASH FIRE project, design and installation guidelines for supplementary automatic water-based fire sprinkler systems were developed. An important design feature is that the system automatically activates at an early stage of a fire. This would allow more time to fight the fire manually or to safely evacuate the space and discharge the CO2 system when the fire is controlled to one or a few vehicles instead of at a time when it has escalated in size. The work was partly based on a comprehensive literature review that identified relevant standards and information applicable to the design of automatic fire sprinkler and deluge water spray systems. Large-scale fire tests verified that the suggested system designs were able to provide control of realistic vehicle fires, including fires in passenger cars and a freight truck.

Fire Safety of Battery Electric Vehicles: Hazard Identification, Detection, and Mitigation

&lt;div&gt;Battery electric vehicles (EVs) bring significant benefits in reducing the carbon footprint of fossil fuels and new opportunities for adopting renewable energy. Because of their high-energy density and long cycle life, lithium-ion batteries (LIBs) are dominating the battery market, and the consumer demand for LIB-powered EVs is expected to continue to boom in the next decade. However, the chemistry used in LIBs is still vulnerable to experiencing thermal runaway, especially in harsh working conditions. Furthermore, as LIB technology moves to larger scales of power and energy, the safety issues turn out to be the most intolerable pain point of its application in EVs. Its failure could result in the release of toxic gases, fire, and even explosions, causing catastrophic damage to life and property. Vehicle fires are an often-overlooked part of the fire problem. Fire protection and EV safety fall into different disciplines. To bridge the gap between these two disciplines and summarize the state-of-the-art knowledge of fire safety issues of EVs, this review article will provide a comprehensive overview of their fire hazard identification, detection, and mitigation strategies. This article also highlights the failure mechanisms of LIBs in EVs, which establish the basis for understanding the LIB fire safety issues in EVs. The aim of this review article is to provide a general and basic understanding of the fire hazards of EVs from different scales to both engineers and researchers. This review article can also be used as educational material for the public and emergency responders to increase their awareness of the fire safety of modern EVs.&lt;/div&gt;

Reinforced Concrete Bridge Column Multihazard Performance: A Computational Tool to Assess Response to Vehicle Impact, Air Blast, and Fire

Reinforced Concrete Bridge Column Multihazard Performance: A Computational Tool to Assess Response to Vehicle Impact, Air Blast, and Fire

Automatic fire extinguishing system of the engine compartment of the car

The article discusses the statistics of vehicle ignition, the existing number of fire safety devices, their advantages and disadvantages. A technical solution is proposed based on the use of a dispersant sprayer, which allows mixing various chemicals into a ready-made fire extinguishing mixture, ejecting and spraying within a single process on the ignition source that has arisen in the engine compartment of the car. Keywords car safety, vehicle fires, engine compartment, statistics of car fires, fire extinguishing devices, dispersant sprayer, new technical solution

Significance of combustion accelerator traces in criminal investigations of intentionally set vehicle fires

Significance of combustion accelerator traces in criminal investigations of intentionally set vehicle fires

Perceived and Actual Fire Safety – Case of Hybrid and Electric Vehicle Fires in Finland 2015–2023

As an emerging technology, hybrid and electric vehicles draw media attention and so does their fire safety. For this article, Finnish national rescue task database (Pronto) was reviewed for electric and hybrid vehicle fires for years 2015–2023, and the 44 records found were analyzed for the fire behavior and the successfulness of the rescue operation. Hybrid and electric vehicle fires are both absolutely and relatively rare compared to conventional vehicle fires. The incident rate for plug-in vehicles has been 0.2–0.9 per 10000 vehicles per year in the 2020s, which is significantly smaller than the rate for all passenger vehicles (4.6). Small absolute number is due to the small total number of hybrid and electric vehicles. Small relative number of fires may be due to the age of vehicles. Electrified vehicles can catch fire while plugged in, parked or while driving, with no significant differences in the incidence of the state of the vehicle. In road accidents, only one vehicle caught fire after a crash. All electric vehicle fires, even if the lithium-ion traction battery is involved, successfully extinguished with a branch pipe and traditional firefighting gear, as the rescue staff had been trained for handling incidents involving electric vehicles. There exists a media bias in reporting battery electric vehicle fires: of all 5 fires of BEV origin found, 4 have been reported in the media as an electric vehicle fire.

Investigation of Water Ingress Driven Circuit Board Faults As a Contributory Factor to Battery Thermal Runaway

Recent high-profile examples of battery fires in electric vehicles (EV’s) during the aftermath of Hurricane Ian [1] have led to increased public visibility of the susceptibility of EV batteries to thermal failure due to water immersion or ingress.Although clearly an issue for manufacturers and users of automotive EV’s, this issue poses a particular challenge in the rapidly increasing micromobility market with nearly 800 million battery powered 2- and 3-wheeled vehicles (such as e-bikes or scooters) expected to be in operation by 2040 [2]. With privately owned micromobility vehicles generally not subject to the rigorous servicing or maintenance schedules of automotive EV’s, and fleets of rented e-bikes / scooters subjected to prolonged rough handling and environmental exposure, the risk of failure in these vehicles due to improper handling, water ingress or mechanical abuse is very real.Testing and failure recreation of thermal runaway in lithium-ion based micromobility battery packs within Exponent’s European laboratory (London) has shown that even small amounts of moisture ingress to sensitive electronic components of the battery pack, such as the battery protection circuitry, can lead to thermal runaway of the cells within the battery pack. Such failures are often highly dependent on battery pack design (and physical condition) and may only manifest in the days or weeks after water immersion or ingress.The study presented here investigated specific conditions and behaviours of saltwater ingress-driven circuit board faults in lithium-ion battery packs, and demonstrated localised temperature increases of ~100 °C, even at relatively low fault currents (mA’s), showing the potential for circuit board faults to propagate to cell thermal runaway.Further studies investigated the effect of full, partial and targeted immersion of lithium-ion battery packs in 5 wt% NaCl solution, demonstrating the influence of the volume of water ingress and ingress location within the battery pack on the potential for battery thermal runaway. This paper will also discuss design aspects and/or mitigation methods to protect from such failure modes.[1] - https://content.govdelivery.com/accounts/USDHSFACIR/bulletins/333744b[2] - https://www.faraday.ac.uk/wp-content/uploads/2023/02/Faraday_Insights_16_FINAL.pdf

Full-scale experimental study of the characteristics of electric vehicle fires process and response measures

Fire accidents are a source of concern for electric vehicles (EV). The spread of fire caused by thermal runaway (TR) in a scenario with a high concentration of EVs can result in a serious disaster. In this study, a full-scale EV fire experiment was conducted using thermal abuse to investigate response strategies to EV fires caused by TR. The pattern of TR fires spreading in EV was also investigated. The suppression capabilities of fire blankets, water spray, and compressed air foam on EV fires in the early stages were analyzed. During the test, the temperature distributions inside and outside the vehicle were measured. The maximum temperature recorded in the passenger compartment near the roof was 919.7 °C. The length of the jet flow was estimated from the images, with the longest being approximately 2.56 m. The fire suppression test demonstrated that the fire blankets effectively extinguished flames, and the temperature inside the car gradually decreased. A water mist device can reduce temperature and put out flames. The compressed air foam effectively extinguished the fire, with an average cooling rate of −9.8 °C/s. These results provide information on EV fire response strategies.

Study on flame height and temperature distribution of double-deck bridge fire based on large-scale fire experiments

Vehicle fire is one of the important causes of bridge fires. This study conducted large-scale actual fire experiments by simulating heat release rates (HRR) of oil tank truck fires with 50 MW, 100 MW, and 200 MW in rectangular oil pans of varying sizes. The flame shape and spatial temperature distribution at different HRRs were studied bycontrollingvariables such as wind speed,firesource location, andlayer spacing. The results indicated that the actual HRR of the large-scale fire exceeded the anticipated value. In large-scale fire experiments, flame splitting into two main peaks was observed along the long side of the rectangular oil pan due to the coupling effect of ambient wind, long side, and sidewall effect of the diagonal web member. The average flame height was determined through image processing, and subsequently, a formula for predicting flame height during bridge fires under varying heat release rates was developed through the use of dimensionless analysis and feature length analysis. The spatial temperature distribution in the vertical direction of the axis of the center of the fire source, the temperature distribution of the diagonal web member and the bottom of the dense crossbeams, which are critical components of the bridge, were also analyzed. Furthermore, the conclusion that the flame in the lower bridge space which split into two main peaks is validated by the results. The results of this study can provide important theoretical support for investigating bridge fire resistance strategies.