Fire Characteristics Research Articles

Flame extension length and temperature profile beneath ceiling induced by endwall-attached fire inside compartment with lateral openings

This study experimentally investigated the fire characteristics of endwall-attached fire within the long-narrow compartment, including the flame extension and temperature profile. Experiments were conducted in a reduced scaled compartment featuring multiple lateral openings. Results show that the previous models of flame extension length and temperature rise in the literatures, whether for sidewall fires in tunnels or central fires in compartments with lateral openings, cannot predict the experimental data in this study. A new correlation is proposed for the flame extension length based on non-dimensional heat release rate. The longitudinal temperature profile generated by endwall-attached fires in compartment can be classified into three distinct regions related to the position of the lateral opening: temperature rapid decrease region, temperature slow decrease region, and backflow region at the end of the compartment. A model for the maximum temperature rise and a piecewise equation based on single exponential function for temperature decay profile are proposed, and these equations effectively correlate the experimental data. The findings of this study can deepen the understanding of fire dynamics within similar building structures and have value for the fire hazard assessment.

FADD gene pathogenic variants causing recurrent febrile infection-related epilepsy syndrome: Case report and literature review.

FIRES and NORSE are clinical presentations of disease processes that, to date, remain unexplained without an established etiology in many cases. Neuroinflammation is thought to have paramount importance in the genesis of these conditions. We hereby report the clinical, EEG, brain MRI, and genetic findings of a nuclear family with recurrent febrile-related encephalopathy with refractory de novo Status Epilepticus. Whole-exome sequencing (WES) revealed a homozygous p.C105W pathogenic variant of FADD gene (FAS-associated protein with death domain, FADD), known to cause ultrarare forms of autosomal recessive immunodeficiency that could be associated with variable degrees of lymphoproliferation, cerebral atrophy, and cardiac abnormalities. The FADD-related conditions disrupt FAS-mediated apoptosis and can cause a clinical picture with the characteristics of FIRES. This observation is important because, on one hand, it increases the number of reported patients with FADD deficiency, showing that this disorder may present variable expressivity, and on the other hand, it demonstrates a genetic cause of FIRES involving a cell-mediated inflammation regulatory pathway. This finding supports early treatment with immunomodulatory therapy and could represent a new avenue of research in the field of new onset refractory status epilepticus and related conditions.

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.

Assessing the Fire Characteristics of Chair Materials in a New High-Speed Railway Vehicle Across Various Fire Environments

The heat release rate generated when a fire occurs in a railway vehicle is one of the most important factors when designing precautions for railway facilities such as railway tunnels. In this study, the fire characteristics of interior materials required to analyze the propagation of a fire in a new railway vehicle were identified via an experimental method. The fire characteristics of the main interior materials across various radiant heat fluxes were analyzed, and the ignition temperature of the interior materials was predicted using the heat release rate and ignition time. By predicting the ignition temperature, the critical heat flux and ignition temperature were confirmed to be low for the flooring of the main interior materials. The derived fire characteristics (ignition temperature and heat release rate) for each material can be used to analyze the fire propagation phenomenon in railway cars.

Evaluation of Thermal Radiation Blocking Effect of Water Mist Curtain in Fire of Hazardous Material Storage Tank

In this study, the thermal radiation blocking effect of a water mist curtain in a full-scale hazardous material storage tank fire was numerically simulated. A fire dynamics simulator (FDS) was used for the numerical simulation, and the accuracy of the heat flux prediction of the FDS was verified using an earlier experimental study on a full-scale hazardous material storage tank fire. Subsequently, a water mist curtain system was installed in a full-scale hazardous material storage tank, and the effects of fire source conditions and water mist curtain characteristics on the heat flux and thermal radiation blocking rate of the water mist curtain were examined. The results of the numerical simulation showed that the water mist curtain decreased the heat flux and increased the thermal radiation blocking rate when the fire source was a tank and dike and when the nozzle had a large spray angle and a small droplet size. Near the adjacent protected tank (in the height of 2∼14 m from the ground at the nozzle installation position), the thermal radiation blocking rate of the water mist curtain was measured to be 62.5∼72.4% and 33.5∼67.4% for the tank and dike fire and the tank fire, respectively, 62.5∼72.4% and 54.4∼65.3% for the spray angles of 180° and 90°, respectively, and 62.5∼72.4% and 71.2∼83.0% for the droplet sizes of 400 and 200 µm, respectively. This study confirmed that the water mist curtain could effectively block the thermal radiation from the fire tank to the adjacent tanks during a full-scale hazardous material storage tank fire.

Study on Hydrocarbon Fuel Ignition Characterization Based on Optimized BP Neural Network

The investigation of the ignition delay of hydrocarbon fuel is highly valuable for enhancing combustion efficiency, optimizing fuel thermal efficiency, and mitigating pollutant emissions. This paper has developed a BP-MRPSO neural network model for studying hydrocarbon fuel ignition and clarified the novelty of this model compared to the traditional BP and ANN models from the literature. The model integrates the particle swarm optimization (PSO) algorithm with MapReduce-based parallel processing technology. This integration improves the prediction accuracy and processing efficiency of the model. Compared to the traditional BP model, the BP-MRPSO model can increase the average correlation coefficient, from 0.9745 to 0.9896. The R2 value for predicting fire characteristics using this model can exceed 90%. Meanwhile, when the two hidden layers of both the BP and BP-MRPSO models consist of 9 and 8 neurons, respectively, the accuracy of the BP-MRPSO model is increased by 38.89% compared to the BP model. This proved that the new BP-MRPSO model has the capacity to handle large datasets while achieving great precision and efficiency. The findings could provide a new perspective for examining the properties of fuel ignition, which is expected to contribute to the development and assessment of aviation fuel ignition characteristics in the future.

Spatiotemporal dynamics of forest fires in the context of climate change: a review.

Forest fires are sudden, destructive, hazardous, and challenging to manage and rescue, earning them a place on UNESCO's list of the world's eight major natural disasters. Currently, amid global warming, all countries worldwide have entered a period of high forest fire incidence. Due to global warming, the frequency of forest fires has accelerated, the likelihood of large fires has increased, and the spatial and temporal dynamics of forest fires have shown different trends. Therefore, the impact of climate change on the spatiotemporal dynamics of forest fires has become a hot issue in the field of forest fire research in recent years. Therefore, it is of great significance and necessity to conduct a review of the research in this area. This review delves into the interactions and impacts between climate change and the spatiotemporal dynamics of forest fires. To address this issue, scholars have mainly adopted the following research methods: first, statistical analysis methods, second, the establishment of spatiotemporal prediction models for meteorology and forest fires, and third, the coupling of climate models with forest fire risk forecasting models. The statistical analysis method relies on the analysis of historical meteorological and fire-related data to study the effects of climate change and meteorological factors on fire occurrence. Meanwhile, forest fire prediction models utilize technical tools such as remote sensing. These models synthesize historical meteorological and fire-related data, incorporating key meteorological factors such as temperature, rainfall, relative humidity, and wind. The models revealed the spatial and temporal distribution patterns of fires, identified key drivers, and explored the interactions between climate change and forest fire dynamics, culminating in the construction of predictive models. With the deepening of the study, the coupling of climate models and fire risk ranking systems became a trend in the prediction of forest fire risk trends. Moreover, as the climate warms, the increased frequency of extreme weather events like heatwaves, droughts, snow and ice storms, and El Niño-Southern Oscillation (ENSO) has accelerated forest fire occurrences and raised the risk of major fires. This review offers valuable technical insights by comprehensively analyzing the spatial and temporal characteristics of forest fires, elucidating key meteorological drivers, and exploring potential mechanisms. These insights serve as a scientific foundation for preventive measures and effective forest fire management. In the face of a changing climate, this synthesis contributes to the development of informed strategies to mitigate the escalating threat of forest fires.

Experimental investigation on flame characteristics in a linear array of dual spill fire

In the process of petroleum production and transportation, a porous leakage accident can easily lead to combustion behaviors such as fire merging, resulting in more severe consequences. This study explores the combustion characteristics of merging spill fires through experimental investigations, incorporating dual leakage holes with varying spacing to examine their impact on the combustion process. The experimental results suggest that the flame height undergoes a pattern of initial decrease followed by an increase with the gradual expansion of leakage spacing, owing to the coupling effects of air entrainment and thermal radiation feedback within the additional entrainment zone. Based on the developmental pattern of flames with respect to leakage spacing, this study categorizes the dual spill fire into three states: which are: (1) full merging state, (2) intermittent merging state, and (3) separation state. The flame height prediction model is established for different merging states, considering parameters such as the fuel discharge rate and the leakage spacing of dual spill fire. The experiment reveals that the flame pulsation frequency (FPF) of the spill fire follows the pattern observed in pool fire FPF, and an FPF model for dual spill fire in all states is obtained through the fitting. Finally, the coupled heat transfer between dual fire sources is considered, and a burning rate model for dual spill fire in intermittent merging states is established.

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 of a Fire-Resistant Plate Containing Fly Ashes Generated from Municipal Waste Incinerator: Fire and Mechanical Characteristics and Environmental Life Cycle Assessment.

The recycling of fly ash from municipal solid waste incineration is currently a global issue. This work intends to examine the viability of a novel recycling alternative for fly ashes as a component of fire-resistant plates. To lessen the quantity of heavy metal leaching, the fly ash was utilized after being washed using a water/fly ash ratio of 2 for one hour. Subsequently, an inexpensive, straightforward molding and curing process was used to create a plate, with a composition of 60%wt of MSWI-FA, 30%wt of gypsum, 0.5%wt of glass fiber and 9.5%wt of vermiculite. The plate exhibited high fire resistance. Furthermore, it demonstrated compression, flexural strength and surface hardness slightly lower than the requirements of European Standards. This allows for manufacturing plates with a high washed MSWI-FA content as fire protection in firewalls and doors for homes and commercial buildings. A Life Cycle Assessment was carried out. The case study shows that a 60% substitution of gypsum resulted in an environmental impact reduction of 8-48% for all impact categories examined, except four categories impacts (marine eutrophication, human toxicity (cancer), human non-carcinogenic toxicity and water depletion, where it increased between 2 and 718 times), due to the previous washing of MSWI-FA. When these fly ashes are used as a raw material in fire-resistant materials, they may be recycled and offer environmental advantages over more conventional materials like gypsum.

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.

Effect of width on the fire spreading characteristics of PE metal sandwich panels under the action of double fire sources

The exterior walls of high-rise buildings typically contain substantial thermal insulation materials. Once ignited, these materials can readily induce major fire accidents. In this study, through the constructed reduced-size experimental bench to evaluate the effect of window overflow fire and upper chamber fire on the fire spreading properties of PE metal sandwich panels with different widths. The result shows that the average flame height and flame oscillation intensity increased with an increase in fire source power and sandwich panel width. Temperature curves exhibited a consistent trend under different working conditions. Dimensionless analysis of the sandwich layer temperature indicated that under specific fire source power conditions, the 60 cm sandwich panel reached the highest peak temperature and posed the greatest fire hazard. Based on the width and length of the preheating zone, a model for the rate of flame spreading was created. At a constant sample width, the accelerated spread of the upper part of the plate by the action of fire source B was more obvious. These conclusions are instructive for the study of building facade fire.

Fire behavior of furfurylated paulownia wood

ABSTRACT Wood is an aesthetically pleasing, sustainable material for various uses. All materials, including wood, are intended to be long-lasting, maintaining their original appearance. The effects of furfurylation on the fire characteristics of wood are still unclear, even though it significantly increases the dimensional stability, hardness, and biodegradation resistance of wood. This study aimed to evaluate the fire characteristics of furfurylated wood. Thermogravimetric analysis showed that the time required for the infiltration of furfuryl alcohol into the samples significantly exceeded the values commonly reported in the literature. The results obtained by measurements on a cone calorimeter indicate that furfurylation significantly increases peak values of heat release rate, carbon monoxide, carbon dioxide, and smoke production in the phase immediately after the initiation. On the contrary, carbon-monoxide (CO) production decreased in the phase of heterogeneous combustion of carbonaceous residue.

Inhibition performances of lithium-ion battery pack fires by fine water mist in an energy-storage cabin: A simulation study

Fire incidents in energy storage stations are frequent, posing significant firefighting safety risks. To simulate the fire characteristics and inhibition performances by fine water mist for lithium-ion battery packs in an energy-storage cabin, the PyroSim software is used to build a 1:1 experimental geometry model of a containerized lithium-ion energy storage cabin. The simulation reveals five stages and their characteristic parameter variations during a fire incident: initial temperature rise, flame generation, flame spread, stable combustion, and flame extinguishment. By adjusting various parameters of the fine water mist, the design of the fine water mist firefighting system for containerized energy storage units is optimized. The simulation results indicate that the optimal inhibition effect for the energy storage cabin's fine water mist firefighting system is achieved when the spray intensity is ≥24 l/min, the fog cone angle is 76°, nozzle velocity is 10 m/s, and the optimal particle size of the fine water mist is 50 μm. The research findings not only provide a rational method and theoretical guidance for the numerical simulation of thermal runaway in lithium batteries but also offer theoretical data support for the safety design and protection of future energy storage cabins.

Experimental study of smoke characteristics in a double-deck tunnel with multiple point extraction using a branch pipe

A reduced scale 1:8 double-deck tunnel model was built to study smoke control performance of a semi-transverse ventilation system using a branch pipe to connect the lower deck tunnel to the upper smoke duct. 41 experiments were conducted to analyze the effects of different activation modes of smoke vents, heat release rate (HRR), and exhaust smoke rates on smoke spread distance. An optimum smoke control mode was found by activating two vents near the fire source when the heat release rate was 44.19 kW (8 MW at full scale) and the fan's extraction rate was 0.66 m3/s (120 m3/s at full scale) using a branch pipe. Results showed that as HRRs rise, the smoke spread distance first increases and then remains constant. The ratio of the smoke spreading distance on the upstream side of the fire to the total smoke spreading distance was 0.4 in this experimental setup. Furthermore, fire smoke spread characteristics were quantified for a typical ventilation design.

Evaluating the Alaska Blocking Index as an indicator of wildfire potential in Alaska's central eastern interior

AbstractIncreased Arctic air temperatures and evaporative fluxes have coincided with more frequent and destructive high‐latitude wildfires. Arctic fires impact ecosystems and people, especially at the community‐level by degrading air quality, destroying agriculture, and threatening life and property. Central Eastern Interior (CEI) Alaska is one such region that has recently experienced the effects of wildfire activity related to warming air temperatures. To improve our ability to identify fire weather events and assess their potential for extreme outbreaks at actionable lead times relevant to fire weather forecasters and managers, new metrics and approaches need to be established and applied toward understanding the physical mechanisms underlying such wildland fire characteristics. Our study uses a new, regional atmospheric circulation metric, the Alaska Blocking Index (ABI), to describe midtropospheric air pressure around Alaska, which is subsequently related to CEI fire weather conditions at the Predictive Service Area (PSA) scale in climatological and extreme events frameworks. Of note, during years of high fire activity, Build‐Up Index (BUI) values tend to be anomalously high during the duff and drought phases across the CEI PSAs, though comparatively lower BUI values are still associated with high fire activity in the Tanana Zone‐South (AK03S) PSA. Likewise, extreme BUI values are strongly tied to high ABI values and well‐defined upper‐air ridging circulation patterns in the duff and drought periods. The statistical skill of mean daily ABI values in the 6–10 day period preceding extreme duff period BUI values is modest (τ2 > 14%) in the Upper Yukon Valley (AK02) PSA, a hotbed of wildland fire activity. Extremes in ABI and CEI BUI often occur in tandem, yielding regional predictability of upper‐air weather patterns and extremes and underlying surface weather conditions, by statistical and/or dynamical forecast models, imperative for local community and governmental organizations to effectively manage and allocate Alaska's fire weather resources.

Is biochar a suitable fire retardant for furfurylated wood?

Wood is a very aesthetically pleasing and environmentally friendly material that can be used both indoors and outdoors. Many research teams are now paying closer attention to polymer modification using furfuryl alcohol or biochar because of its potential for commercial applications. It is anticipated that this kind of material will be long-lasting and maintain its mechanical properties over time. In this paper, spruce wood was modified by a furfuryl alcohol solution enriched by biochar using vacuum infiltration. Therefore, the purpose of this work was to investigate whether spruce wood was suitable for this treatment and to evaluate the effects of thermal degradation properties on prepared composite. Thermogravimetric analysis of raw wood (W), furfurylated wood (FW), and biochar-furfurylated wood bio-composite (BFW) reveals significant differences in its thermal stability. Wood exhibits the lowest thermal stability due to its composition. BFW showed higher thermal stability than wood. FW decomposes similarly to BFW but shows higher mass loss at low temperatures. The obtained results proved increasing two key fire characteristics (decrease of effective heat of combustion and carbon monoxide yield) of BFW in comparison with pristine spruce wood.

Numerical investigation on the air inflow rate for fuel-controlled compartment fire under ambient wind condition

So far, extensive researches have been conducted on compartment fire characteristics in no wind conditions. However, there are still few researches focusing on the air flow rate through opening of compartment under influence of ambient wind, noting that the air inflow rate is related to fire growth, indoor temperature, heat convection between indoor and outdoor environments, and the corresponding thermal impact to adjacent rooms. This paper investigated the air flow rate for fuel-controlled compartment fire under the ambient wind through numerical simulation. Temperature inside compartment, gas velocity along the opening vertical centerline and the air inflow rate were obtained for various fuel supply rates and wind speeds. Results show that: (1) The air inflow rate increases as the opening size increases. (2) The air inflow rate increases as the fire heat release rate increases, and the increasing rate decreases for higher fire heat release rates. (3) The air inflow rate increases as wind speed increases. Influence mechanism of ambient wind was revealed through pressure analysis, including the static pressure and dynamic pressure. A Froude number was proposed to describe the wind pressure effect, then the air inflow rate model was established, which has good consistency with the simulated data.

Study on Smoke Propagation Characteristics of a Carriage Fire in Longitudinally Ventilated Tunnel

Study on Smoke Propagation Characteristics of a Carriage Fire in Longitudinally Ventilated Tunnel

Investigation of fire regime dynamics and modeling of burn area over India for the twenty-first century.

The characteristics of the vegetation fire (VF) regime are strongly influenced by geographical variables such as regional physiographic settings, location, and climate. Understanding the VF regime is extremely important for managing and mitigating the impacts of fires on ecosystems, communities, and human activities in forest fire-prone regions. The present study thereby aimed to explore the potential effects of the confounding factors on VF in India to offer actionable and achievable solutions for mitigating this concurring environmental issue sustainably. A global burn area (250m) data (Fire-CCIv5.1) and fire radiative power (FRP) were used to investigate the dynamics of VF across seven different divisions in India. The study also used the maximum and minimum temperatures, precipitation, population density, and intensity of human modification to model forest burn areas (including grassland). The Coupled Model Intercomparison Project-6 (CMIP6) was used to predict the burn area for 2030 and 2050 future climate scenarios. The present study accounted for a sizable increasing trend of VF during 2001-2019 period. The highest increasing trend was found in central India (513 and 343 km2year-1 in the forest and crop fire, respectively), followed by southern India (364 km2year-1 in forest fire), and upper Indo-Gangetic plain (128 km2year-1 in crop fire). The FRP has varied significantly across the divisions, with the north-eastern Himalayas exhibiting the highest FRP hotspot. The maximum and minimum temperatures have the greatest influence on forest fires, according to Random Forest (RF) modeling. The estimated pre-monsoonal burn area for 2050 and 2050 future scenarios suggested a more frequent forest fire occurrence across India, particularly in southern and central India. A comprehensive forest fire control policy is therefore essential to safeguard and conserve forest cover in the regions, affected by forest fire periodically.