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In order to study the influence of wind direction on fire spread on building facades, a three-dimensional model of a high-rise building was built with PyroSim software. Numerical simulations were conducted with five wind directions (0°, 45°, 90°, 135° and 180°) and a reference wind speed of 3 m/s. The results show that the fire spread on the building facade was most significant on the leeward side, followed by the upwind condition. The horizontal spread of fire was promoted by crosswinds at 45°, 90° and 135°, while its vertical spread was inhibited. Among these, the inhibitory effect of the 45° crosswind was the greatest. The fire spread area under the leeward condition was the greatest at approximately 341.3 m2, accounting for 17.1% of the facade, and the vertical spread velocity under the condition of no wind was the fastest at 0.075 m/s. In this study, the motion characteristics of facade fire spread under different wind directions were determined, providing supporting evidence to enhance fire safety prevention and control measures in high-rise buildings. [ABSTRACT FROM AUTHOR]

Background. Accurate quantification of emissions from peatland wildfire is crucial for understanding their feedback to the atmospheric and Earth system. However, current knowledge on this topic is limited to a few laboratory and field studies, which report substantial variability in terms of the fire emission factors (EFs). Aims. We aim to understand how emissions vary across the life cycle of a peatland fire. Methods. In August/September 2018, we conducted the largest and longest to-date field-scale experimental burn on a tropical peatland in Sumatra, Indonesia. Field measurements of gas emissions from the fire experiment were conducted using an openpath Fourier transform infrared spectroscopy to retrieve mole fractions of 11 gas species. Key results. For the first time, we calculated and reported EFs from 40 measurement sessions conducted over 2 weeks of burning, encompassing different fire stages (e.g. ignition, smouldering spread, and suppression) and weather events (e.g. rainfall). Our findings provide field evidence to indicate that EFs vary significantly among fire stages and weather events. We also observed that the heterogeneous physicochemical properties of peatland site (e.g. moisture content) influenced the EFs. We also found that modified combustion efficiency was highly sensitive to complex field variables and could introduce large uncertainties when determining the regimes of a peat fire. Conclusions and implications. Further studies to investigate peat fire emissions are needed, and more comprehensive mapping of peatland heterogeneity and land use for emissions inventories, accounting for spatial and temporal variability in EFs since the initiation of a fire event is required. [ABSTRACT FROM AUTHOR]

The frequency of urban fires has grown in recent years everywhere, especially in historic districts, including in Portugal, due to the existence of sensitive igniting materials, the proximity of buildings, the complex urban layout, and the presence of many people. The current study proposes a technique, applied in the Baixa Pombalina (downtown) area in Lisbon, to undertake an appropriate evaluation of the post-earthquake fire cascading effect, which may cause major damage. The earthquake vulnerability and damage scenario were carried out using the Risk-UE method. An empirical fire ignition model was then applied to determine the quantity and location of fire ignitions for different return periods. Furthermore, the simple fire spread Hamada's model was applied to both the equally spaced grid buildings, as in the original Hamada procedure, and the current study area layout for different time thresholds. Finally, the risk assessment for both models was carried out, allowing for the estimation of earthquake and fire losses, respectively. The results demonstrated that the models are comparable, showing that the Hamada model might be a useful tool for large-scale evaluations aimed at disaster-risk reduction and management since it gives useful information for managing and reducing natural and anthropogenic hazards. [ABSTRACT FROM AUTHOR]

The main objective of this research is to establish a quantitative risk assessment method for fire spread in enclosed building scenarios. The enclosed building fire spread process is divided into three stages: fire fully developed in the fire compartment, failure of weak barrier, and combustibles ignited in the target compartment. The calculation method for fire spread is established, where the time for fire fully developed is calculated based on the t2 fire, the barrier failure time is calculated based on the finite difference method, and the combustible ignition time is calculated based on the zone model. The linear regression model is formulated to ensure computational efficiency for fire spread time prediction. The enclosed building fire spread quantitative risk assessment method is proposed based on the Probit model. The effectiveness of the risk assessment method is validated through the enclosed building fire spread experiment, and the method is applied to assess the risk of fire spread in an office. The results demonstrate that the method could quantitatively assess fire spread risk under different conditions with high computational efficiency and excellent versatility, and it could provide guidance for fire prevention, building fire design, and fire rescue. [ABSTRACT FROM AUTHOR]

Introduction: The behavior of forest fire is a complex phenomenon, and accurate simulation of forest fire is conducive to emergency response management after ignition. In order to further understand the characteristics of forest fire spread and the applicability of WRF-Fire in China, which is a coupled fire-atmospheric wildfire model, this study simulated a high-intensity forest fire event that occurred on October 17, 2022 in Xintian County, southern Hunan Province. Methods: Based on the fire-atmosphere coupled WRF-Fire model, we used high-resolution geographic information, meteorological observation and fuel classification data to analyze the forest fire behavior. At the same time, the simulation results are compared with the fire burned area observed by satellite remote sensing forest fire monitoring data. Results: The study found that, the simulated wind speed, direction and temperature trends are similar to the observation results, but the simulated wind speed is overestimated, the dominant wind direction is N, and the temperature is slightly underestimated. The simulated wind field is close to the actual wind field, and the simulation results can show the spatial and temporal variation characteristics of the local wind field under complex terrain while obtaining the high-resolution wind field. The simulated fire burned area is generally overestimated, spreading to the north and southwest compared with the observed fires, but it can also capture the overall shape and spread trend of the fire well. Discussion: The results show that the model can accurately reproduce the real spread of fire, and it is more helpful to forest fire management. [ABSTRACT FROM AUTHOR]

This paper investigates the impact of window partition walls on the spread of fire on building facades under the impact of environmental wind through Fire Dynamics Simulator simulation experiments. A four-story building model was constructed using a Fire Dynamics Simulator incorporating six different wind speed conditions and six different partition wall widths. The fire-blocking performance of window partition walls of varying widths was systematically compared and analyzed, and the data indicated: (1) Under calm wind conditions, the installation of window partition walls is observed to facilitate the vertical spread of facade fires. Moreover, as the width of these partition walls increases, this facilitative effect becomes increasingly prominent; (2) Under wind speeds of 0 to 5 m/s, the temperature on the leeward side is lower when window partition walls are present than when they are absent. This indicates that window partition walls inhibit the horizontal spread of building facade fires, and wider window partition walls have better horizontal fire resistance performance. [ABSTRACT FROM AUTHOR]

Introduction: Climate change is predicted to increase the frequency of extreme single-day fire spread events, with major ecological and social implications. In contrast with well-documented spatio-temporal patterns of wildfire ignitions and perimeters, daily progression remains poorly understood across continental spatial scales, particularly for extreme single-day events ("blow ups"). Here, we characterize daily wildfire spread across North America, including occurrence of extreme singleday events, duration and seasonality of fire and extremes, and ecoregional climatic niches of fire in terms of Actual Evapotranspiration (AET) and Climatic Water Deficit (CWD) annual climate normals. Methods: Remotely sensed daily progression of 9,636 wildfires =400 ha was used to characterize ecoregional patterns of fire growth, extreme single-day events, duration, and seasonality. To explore occurrence, extent, and impacts of single-day extremes among ecoregions, we considered complementary ecoregional and continental extreme thresholds (Ecoregional or Continental Mean Daily Area Burned + 2SD). Ecoregional spread rates were regressed against AET and CWD to explore climatic influence on spread. Results: We found three-fold differences in mean Daily Area Burned among 10 North American ecoregions, ranging from 260 ha day-1 in the Marine West Coast Forests to 751 ha day-1 in Mediterranean California. Ecoregional extreme thresholds ranged from 3,829 ha day-1 to 16,626 ha day-1, relative to a continental threshold of 7,173 ha day-1. The ~3% of events classified as extreme cumulatively account for 16-55% of total area burned among ecoregions. We observed four-fold differences in mean fire duration, ranging from 2.7 days in the Great Plains to 10.5 days in Northwestern Forested Mountains. Regions with shorter fire durations also had greater daily area burned, suggesting a paradigm of fastgrowing short-duration fires in some regions and slow-growing long-duration fires elsewhere. CWD had a weak positive relationship with spread rate and extreme thresholds, and there was no pattern for AET. Discussion: Regions with shorter fire durations had greater daily area burned, suggesting a paradigm of fast-growing short-duration fires in some regions and slow-growing long-duration fires elsewhere. Although climatic conditions can set the stage for ignition and influence vegetation and fuels, finer-scale mechanisms likely drive variation in daily spread. Daily fire progression offers valuable insights into the regional and seasonal distributions of extreme single-day spread events, and how these events shape net fire effects. [ABSTRACT FROM AUTHOR]

The dynamic behaviour of wildfires is mainly influenced by weather, fuel, and topography. Based on fundamental conservation laws involving numerous physical processes and large scales, atmospheric models require substantial computational resources. Therefore, coupling wildfire and atmospheric models is impractical for high resolutions. Instead, a static atmospheric wind field is typically input into the wildfire model, either as boundary conditions on the control surface or distributed over the control volume. Wildfire propagation models may be (i) data-driven ; (i i) theoretical ; or (i i i) mechanistic surrogates. Data-driven models are beyond the scope of this paper. Theoretical models are based on conservation laws (species, energy, mass, momentum) and are, therefore, computationally intensive; e.g. the Fire Dynamics Simulator (FDS). Mechanistic surrogate models do not closely follow fire dynamics laws, but related laws observed to make predictions more efficiently with sufficient accuracy; e.g. FARSITE, and FDS with the Level Set model (FDS-LS). Whether theoretical or mechanistic surrogate, these wildfire models may be coupled with or decoupled from wind models (e.g. Navier-Stokes equations). Only coupled models account for the effect of the fire on the wind field. In this paper, a series of simulations of wildfire propagation on grassland are performed using FDS-LS to study the impact of the fire-induced wind on the fire propagation dynamics. Results show that coupling leads to higher Rates of Spread (RoS), closer to those reported from field experiments, with increasing wind speeds and higher terrain slopes strengthening this trend. Aiming to capture the fire–wind interaction without the hefty cost of solving Navier-Stokes equations, a conceptual framework is proposed: 1) a swarm of unmanned aerial vehicles measure wind velocities at flight height; 2) the wind field is constructed with the acquired data; 3) the high-altitude wind field is mapped to near-surface, and 4) the near-surface wind field is fed into the wildfire model periodically. A series of simulations are performed using an in-house decoupled physics-based reduced-order fire propagation model (FireProM-F) enhanced by wind field "measurements". In this proof of concept, wind velocities are not measured but extracted from physics-based Large Eddy Simulations taken as ground truth. Unsurprisingly, higher measurement frequencies lead to more accurate and realistic predictions of the propagating fire front. An initial attempt is made to study the effect of wind measurement uncertainty on the model predictions by adding Gaussian noise. Preliminary results show that higher noise leads to the fire front displaying more irregular shapes and slower propagation. • Higher wildfire model prediction accuracy normally achieved by coupling it with wind model such as Navier-Stokes equations. • Coupled fire-wind models often too computationally expensive for real-time use in operational contexts. • Prediction accuracy of wildfire model uncoupled from wind model enhanced by periodic inputs of updated wind field. • Wind field to be constructed from UAV swarm measurements, surrogated here to velocities obtained from full CFD simulations. • Proposed method to enhance wildfire model predictions robust to Gaussian noise added to represent measurement uncertainty. [ABSTRACT FROM AUTHOR]

Basic principles for a fire‐safe application of green façades on multi‐storey buildings. Green façades are in vogue. Fire spread along the façade is generally one of the most critical fire scenarios worldwide, and plants are additional combustible materials. The influence of green façades on fire propagation along the façade should therefore not be neglected. However, little research is available on this topic. The FireSafeGreen research project aims to change this. The main factor influencing the fire behaviour of plants is the moisture content. The plant species itself plays a subordinate role in terms of fire behaviour. A combination of wooden and green façade does not lead to an ignition of the wooden façade under consideration of some boundary conditions. In principle, appropriate care and maintenance are the key factors for fire‐safe green façades. [ABSTRACT FROM AUTHOR]

Recently burned boreal forests have lower aboveground fuel loads, generating a negative feedback to subsequent wildfires. Despite this feedback, short‐interval reburns (≤20 years between fires) are possible under extreme weather conditions. Reburns have consequences for ecosystem recovery, leading to enduring vegetation change. In this study, we characterize the strength of the fire‐fuel feedback in recently burned Canadian boreal forests and the weather conditions that overwhelm resistance to fire spread in recently burned areas. We used a dataset of daily fire spread for thousands of large boreal fires, interpolated from remotely sensed thermal anomalies to which we associated local weather from ERA5‐Land for each day of a fire's duration. We classified days with >3 ha of fire growth as spread days and defined burned pixels overlapping a fire perimeter ≤20 years old as short‐interval reburns. Results of a logistic regression showed that the odds of fire spread in recently burned areas were ~50% lower than in long‐interval fires; however, all Canadian boreal ecozones experienced short‐interval reburning (1981–2021), with over 100,000 ha reburning annually. As fire weather conditions intensify, the resistance to fire spread declines, allowing fire to spread in recently burned areas. The weather associated with short‐interval fire spread days was more extreme than the conditions during long‐interval spread, but overall differences were modest (e.g. relative humidity 2.6% lower). The frequency of fire weather conducive to short‐interval fire spread has significantly increased in the western boreal forest due to climate warming and drying (1981–2021). Our results suggest an ongoing degradation of fire‐fuel feedbacks, which is likely to continue with climatic warming and drying. [ABSTRACT FROM AUTHOR]

Conifer trees (Noble-fir) were used to study the vegetative combustion process under an applied wind field. Three ignition methods were considered. First, a special T-shaped propane burner was used. The second ignition method considered the use of firebrand showers impinging onto the trees. The third method was to use one tree to ignite another tree. Temporally resolved mass loss profiles, as well as firebrand distributions were determined. Results are presented for individual conifer trees combusting under an applied wind field. Additional experiments that made use of up to two trees per experiment were used to observe fire spread processes from tree to tree. These experiments provide the much needed experimental understanding to be able to model vegetative combustion processes. [ABSTRACT FROM AUTHOR]

Understanding wildfire spread in Canada is critical to promoting forest health and protecting human life and infrastructure. Quantifying fire spread from noisy images, where change-point boundaries separate regions of fire, is critical to accurately estimating fire spread rates. The challenge lies in denoising the fire images and accurately identifying highly non-linear fire lines without smoothing over boundaries. In this paper, we develop an iterative smoothing algorithm for change-point data that utilizes oversmoothed estimates of the underlying data generating process to inform re-smoothing. We demonstrate its effectiveness on simulated one- and two-dimensional change-point data, and robustness to response outliers. Then, we apply the methodology to fire spread images from laboratory micro-fire experiments and show that the regions fuel, burning and burnt-out are smoothed while boundaries are preserved. [ABSTRACT FROM AUTHOR]

This study is the first part of a larger investigation into the fire behaviour of green façades. In this study, the currently known international research status on this topic is presented and discussed. In addition, the flammability of green façades is investigated through 43 fire tests on a medium scale according to the SBI (Single Burning Item) test method EN 13823. The focus of the investigation was placed on climbing plants. A total of 25 different plant species were investigated. A comparison of the heat release rate of all the investigated vital plants shows similar behaviour. In the course of exposure, there are short peaks in the heat release rate. These peaks are "flare-ups" that occur when parts of the plants dry out due to exposure to the flame and then ignite. The plant species itself had no substantial influence on fire behaviour. Horizontal fire spread occurred to a very limited extent within the investigations of vital plants. They were self-extinguishing. The significant factor in the assessment of flammability is the moisture content of the plants. With dried plants, an abrupt heat release occurs at the beginning. Dried-out plants, as well as unmaintained plants with a high content of deadwood, represent the most critical case. [ABSTRACT FROM AUTHOR]

In order to study the influence of wind direction on fire spread on building facades, a three-dimensional model of a high-rise building was built with PyroSim software. Numerical simulations were conducted with five wind directions (0°, 45°, 90°, 135° and 180°) and a reference wind speed of 3 m/s. The results show that the fire spread on the building facade was most significant on the leeward side, followed by the upwind condition. The horizontal spread of fire was promoted by crosswinds at 45°, 90° and 135°, while its vertical spread was inhibited. Among these, the inhibitory effect of the 45° crosswind was the greatest. The fire spread area under the leeward condition was the greatest at approximately 341.3 m2, accounting for 17.1% of the facade, and the vertical spread velocity under the condition of no wind was the fastest at 0.075 m/s. In this study, the motion characteristics of facade fire spread under different wind directions were determined, providing supporting evidence to enhance fire safety prevention and control measures in high-rise buildings.

Chemical warehouses are one of the important sources in process units. Locations are one of the issues that should be investigated in closed environments due to the many types of chemicals and storage conditions. In this study, fire dynamics simulation (FDS), was used to simulation of fire in the presence and non-presence of the ventilation system. Then the spread of fire in the warehouse was evaluated based on domino methods and finally the Bayesian network (BN) was used to update the rate of fire spread. The simulation results in this approach showed that the highest amount of heat flux related to iso-octane fire at L/D= 0.3 when the ventilation system is off and the doors are closed. The updated results of the fire spread modeling in BN showed that if a fire occurs in isooctane barrels, it has the highest rate of spread with a probability of 22% and the lowest rate of spread in Diglycolamine(DGA) barrels with a probability of 0.4%. From the results of this study, it is possible to understand the importance of arranging materials according to the principles of compatibility of chemical materials, and based on this, appropriate control measures can be provided. [Display omitted] [ABSTRACT FROM AUTHOR]

One of the primary tools used for determining the origin of a wildfire is analyzing burn patterns formed during the fire progression. These patterns, called fire pattern indicators, are interpreted and used to document the direction of fire movement at specific points, creating a directional map back to the specific area of origin. This concept was first set forth in 1978 by a U.S. governmental organization, the National Wildfire Coordinating Group (NWCG). Their recommendations are currently (2016) in the third edition, and in our study, we examine these indicators. Specifically, the objective was to perform a validation exercise where controlled burns were conducted of natural vegetation plots but augmented with 32 identical sets of staged artifacts which would provide additional opportunities for fire movement to create observable directional fire pattern indicators. Three adjacent plots were burned, each using a single point ignition, all located on level, scrubland terrain. The burns were conducted in the fall season, under low to moderate burning conditions. The research was structured as a preliminary study, since only mild terrain and weather conditions were encompassed. The actual fire movements were documented by drone videos, additional ground-based videos, and still photography. Within the three burn plots, a total of 12 data sites out of 32 data sites were selected: each one containing 7 to 12 individual artifacts. Each artifact was photographically documented post-fire, and the actual fire movement direction at that location was established. Assessment entailed the use of four experienced wildland fire investigators, with each one independently assessing the direction and type of fire spread at each artifact using the photographic site evidence. An analysis was then conducted to make a statistical comparison between the actual fire movement direction and the direction estimates provided by the experts analyzing the photographic evidence and the limited information on conditions provided. The results indicate an average error of 103°. These results indicate that additional efforts are needed to study the scientific basis of the indicators and to evolve improvements in both the indicators and in the accompanying guidance to investigators. [ABSTRACT FROM AUTHOR]

[Objective] Long-narrow confined spaces, while facilitating the mobility and daily lives of urban and rural residents, also pose fire safety concerns. Catastrophic combustion phenomena in such a space can result in significant casualties and property damage. Owing to the coupling effect of the long-narrow space and longitudinal ventilation, the fire plume and smoke layer behavior significantly differ from that of conventional buildings. Therefore, studying fire behavior and smoke spread characteristics under limited boundary conditions holds great scientific significance in thermal safety engineering. Research-oriented experimental teaching plays a crucial role in achieving the educational goals of fire engineering majors. Through scientific research-expanding experiments, students can consolidate and deepen their understanding of combustion science, fire dynamics, and smoke control engineering. It also improves students' independent analysis, problem-solving, comprehensive design, and innovation abilities. Furthermore, a trinity experimental teaching program was established to improve the practical teaching effect by integrating virtual entities, scientific research teaching, and theory experiments. This teaching approach involves conducting physical experiments to observe phenomena, record data, and analyze results. The virtual experiment establishes a virtual simulation scene to simulate the computational fluid dynamics of fluid motion in a fire, uses numerical methods to solve the NS equation of low Mach number flow driven by fire buoyancy, and observes the dynamic flow field parameters through the field simulation results. Building a full-scale test platform for fire science research considering the unique characteristics and high aspect ratio of a long-narrow confined space is difficult. Therefore, downscale experiments are commonly used because of their convenience and cost- effectiveness. [Methods] In this paper, a medium-scale experimental platform is selected for the experimental teaching program. Using a medium-sized experimental platform, the overall arrangement of physical experiments is based on experimental design, system construction, experimental operation, and teaching results. The characteristics of the fire plumes, flame propagation rates, and distribution patterns of fire smoke temperature were investigated. Using PyroSim to establish virtual simulation scenarios, FDS for simulation calculations, and field simulation diagrams to record experimental teaching results, we could perceive the dynamic process of fire occurrence and development. We also analyzed experimental results, such as temperature, velocity vector, and smoke concentration. [Results] The following findings were observed: 1 under longitudinal ventilation conditions, owing to forced convection or buoyancy-induced natural convection, the flame inclines downstream, and the inclination angle increases with the increase in ventilation velocity. 2 Higher wind speeds result in fast changes in the position of the pyrolysis front, increasing flame propagation rates. 3 An increase in wind speed facilitates the expulsion of hot smoke, and the temperature changes with the flow of hot smoke. 4 Temperature differences are observed on both sides of the fire source under the influence of ventilation, and the temperature on the downwind side decreases as the distance from the fire source increases. 5 The wind speed in the smoke backflow region was lower than in other areas. Combustion science, fire dynamics, and smoke control engineering are the core subjects of the fire protection engineering undergraduate program. Owing to classroom instruction constraints, students' understanding of the subject matter is primarily theoretical. However, a three-dimensional understanding of the theoretical concepts can be gained when combined with experiments. This experimental teaching content enhances students' comprehensive abilities to analyze and solve problems during the experimental process, effectively shaping their innovative and practical capabilities. [ABSTRACT FROM AUTHOR]

IntroductionClimate change is predicted to increase the frequency of extreme single-day fire spread events, with major ecological and social implications. In contrast with well-documented spatio-temporal patterns of wildfire ignitions and perimeters, daily progression remains poorly understood across continental spatial scales, particularly for extreme single-day events (“blow ups”). Here, we characterize daily wildfire spread across North America, including occurrence of extreme single-day events, duration and seasonality of fire and extremes, and ecoregional climatic niches of fire in terms of Actual Evapotranspiration (AET) and Climatic Water Deficit (CWD) annual climate normals.MethodsRemotely sensed daily progression of 9,636 wildfires ≥400 ha was used to characterize ecoregional patterns of fire growth, extreme single-day events, duration, and seasonality. To explore occurrence, extent, and impacts of single-day extremes among ecoregions, we considered complementary ecoregional and continental extreme thresholds (Ecoregional or Continental Mean Daily Area Burned + 2SD). Ecoregional spread rates were regressed against AET and CWD to explore climatic influence on spread.ResultsWe found three-fold differences in mean Daily Area Burned among 10 North American ecoregions, ranging from 260 ha day−1 in the Marine West Coast Forests to 751 ha day−1 in Mediterranean California. Ecoregional extreme thresholds ranged from 3,829 ha day−1 to 16,626 ha day−1, relative to a continental threshold of 7,173 ha day−1. The ~3% of events classified as extreme cumulatively account for 16–55% of total area burned among ecoregions. We observed four-fold differences in mean fire duration, ranging from 2.7 days in the Great Plains to 10.5 days in Northwestern Forested Mountains. Regions with shorter fire durations also had greater daily area burned, suggesting a paradigm of fast-growing short-duration fires in some regions and slow-growing long-duration fires elsewhere. CWD had a weak positive relationship with spread rate and extreme thresholds, and there was no pattern for AET.DiscussionRegions with shorter fire durations had greater daily area burned, suggesting a paradigm of fast-growing short-duration fires in some regions and slow-growing long-duration fires elsewhere. Although climatic conditions can set the stage for ignition and influence vegetation and fuels, finer-scale mechanisms likely drive variation in daily spread. Daily fire progression offers valuable insights into the regional and seasonal distributions of extreme single-day spread events, and how these events shape net fire effects.

Fires in the railway trains are prone to cause large numbers of casualties, serious economic losses, and huge negative social impacts. The railway train carriage is a special confined built environment, where the pyrolysis, combustion, and fire spread process are different from those fire accidents in open space. Identifying the fire characteristics of the railway train carriages is the key issue to determine the fire prevention and control strategy. Therefore, this paper attempts to assess and identify the characteristics of pyrolysis, combustion, and fire spread of railway trains based on the exising research. This review documents the pyrolysis and combustion characteristics of single train material and the combustible module, summarizes the heat release rate (HRR) calculation methods and the HRR profile for different types of trains, as well as introduces the research progress in the flame spread and flashover. The main gaps and issues to be solved in terms of the effects of train speed, altitudes, and application of new energy trains are further discussed.

This paper investigates the impact of window partition walls on the spread of fire on building facades under the impact of environmental wind through Fire Dynamics Simulator simulation experiments. A four-story building model was constructed using a Fire Dynamics Simulator incorporating six different wind speed conditions and six different partition wall widths. The fire-blocking performance of window partition walls of varying widths was systematically compared and analyzed, and the data indicated: (1) Under calm wind conditions, the installation of window partition walls is observed to facilitate the vertical spread of facade fires. Moreover, as the width of these partition walls increases, this facilitative effect becomes increasingly prominent; (2) Under wind speeds of 0 to 5 m/s, the temperature on the leeward side is lower when window partition walls are present than when they are absent. This indicates that window partition walls inhibit the horizontal spread of building facade fires, and wider window partition walls have better horizontal fire resistance performance.

Fire is one of the extreme loading events that a building may experience during its service life and can have severe consequences on the safety of its occupants, first responders, and the structure. Steel framed buildings under severe fires can experience high levels of instability at a local or global level, which in turn can lead to the partial or progressive collapse of the structure. However, in current practice, fire resistance of structures is obtained without due consideration to a number of critical factors, and this is mainly due to the high level of complexity in undertaking advanced analysis of structures under fire exposure. This paper presents a parametric study on a ten-story braced steel framed building subjected to fire exposure wherein six different parameters are evaluated: fire severity, fire spread, load paths, temperature-induced creep, local instability, and analysis regime. Results from validated finite element models are utilized to evaluate the influence of the different parameters and recommend critical parameters to be incorporated in the analysis. Results show that the susceptibility of fire-induced progressive collapse significantly depends on the severity of the fire exposure scenario, including fire intensity, fire spread, and extent of burning. Also, accounting for the full effects of transient creep in fire-induced progressive collapse analysis is needed to obtain conservative failure times under severe to very intense fire exposure. Additionally, results from the parametric study infer that the sectional classification of a steel section based on local instability can alter under fire exposure and this effect is more critical in steel columns located in the higher stories of the building; a nonslender column at ambient conditions can transform to a slender section at elevated temperatures. This can induce temperature-induced local instability in the column and lead to an early onset of instability at member and structural levels.

In this study, a numerical technique has been used to analyze the fire propagation and its suppression within the valve hall (VH) for an ultra-high voltage (UHV) converter station. The full-size geometric model of the VH for the converter station and fire model was developed using the simulator. The process of fire propagation upon ignition was thoroughly analyzed with VT (valve tower) fire demonstrating the fastest growth with a growth coefficient of 0.08204. The ceiling impingement jet flow for vertical propagation was analyzed to determine the fire source locations. The temperature of VH tends to remain steady when the merging flame is created which was found to agree with the temperature distribution on VH as devised by Heskestad's model. Spray nozzle diameter, spray jet length, and volume flow rate (VFR) significantly influence the suppression performance. The suppression performance was found to be enhanced with an increasing VFR and subsequently deteriorated with an increasing diameter of the nozzle.

This paper takes a close look at the mechanism of fire spread, highlights some of the fire safety challenges posed by heritage buildings and gives some practical advice on limiting the spread of fire while respecting the historic fabric. [ABSTRACT FROM AUTHOR]

In the history of human civilization, traditional villages and buildings have been significantly threatened by fire. As an essential part of Huizhou traditional architecture, fire seal walls play a crucial role in preserving Huizhou architecture by effectively blocking the spread of fire. However, with economic and social development, the Huizhou fire seal wall's original fire prevention function has been unable to meet the needs of modern fire protection. This study aims to explore the fire performance of different types of Huizhou fire seal walls to provide a reference guide for future fire protection, optimization, and transformation of traditional buildings. In this paper, 3D models of traditional buildings with fire seal walls were built with FDS, and the performance of the different kinds of fire seal walls was simulated under the influence of wind speeds, building spacing, and the height of the vertical ridge of the fire seal wall. The results showed that, under the same conditions, a fire seal wall with a single eave is superior to fire seal walls with quintuple eaves in terms of performance, and fire seal walls with quintuple eaves are superior to fire seal walls with triple eaves in the middle and late stages of a fire. In addition, wind speeds, building spacing, and the height of the vertical ridge have different effects on the fire performance of seal walls. Lower wind speeds can reduce the fire performance of fire seal walls, and no wind and higher wind speeds have no significant effect on the fire performance of fire seal walls, while increasing the height of the vertical ridge and fire spacings appropriately can improve the fire performance of fire seal walls. This study provides a reference guide for future fire protection, optimization, and transformation of Huizhou fire seal walls, which can help improve the fire safety of traditional buildings. [ABSTRACT FROM AUTHOR]

Systematic experiments and complementing numerical simulations have been reported for the first time to understand the spread of a ground fire over pine needle bed of the Siberian boreal forests (Pinus silvestris) in still air. Using equipment and instrumentations specifically developed for the purpose, careful experiments have been conducted to reveal the effects of the bed width, fuel moisture content, fuel load, and the packing ratio on flame spread rate, temperature distributions in both gas and condensed phases. Temperatures are measured using fine thermocouples fixed at various locations from the bed surface. The surface temperature of the bed during flame propagation has been measured using a micro-thermocouple inserted in a single pine needle in the bed as well as using an infrared (IR) camera. Further, for the first time, the total and radiant heat fluxes from the flame to the bed surface have been measured using compact cooled sensors placed inside the needle bed, over which the flame propagates. In order to understand more about the flow field and flame spread process, a 3D numerical model based on the Fire Dynamics Simulator (FDS) has been used to simulate few of the experiments. The processes governing pine needle pyrolysis, char oxidation, gas phase combustion and radiation have been modeled using simplified approaches reported in literature. The model is capable of predicting experimentally measured flame propagation velocities for most of the cases quite well. [ABSTRACT FROM AUTHOR]

The spread of natural fires is a complex issue, as its mathematical modeling needs to consider many parameters. Therefore, the results of such modeling always need to be validated by comparison with experimental measurements under real-world conditions. Remote sensing with the support of satellite or aerial sensors has long been used for this purpose. In this article, we focused on data collection with an unmanned aerial vehicle (UAV), which was used both for creating a digital surface model and for dynamic monitoring of the spread of controlled grassland fires in the visible spectrum. We subsequently tested the impact of various processing settings on the accuracy of the digital elevation model (DEM) and orthophotos, which are commonly used as a basis for analyzing fire spread. For the DEM generated from images taken during the final flight after the fire, deviations did not exceed 0.1 m compared to the reference model from LiDAR. Scale errors in the model with only approximal WGS84 exterior orientation parameters did not exceed a relative accuracy of 1:500, and possible deformations of the DEM up to 0.5 m in height had a minimal impact on determining the rate of fire spread, even with oblique images taken at an angle of 45°. The results of the experiments highlight the advantages of using low-cost SfM photogrammetry and provide an overview of potential issues encountered in measuring and performing photogrammetric processing of fire spread.

Forest fires can result in loss of life, damage to infrastructure, and adverse environmental impacts. This study showcases an integrated approach for conducting high-detail fire risk assessment and supporting strategic planning and management of fire events in peri-urban areas that are susceptible to forest fires. The presented methodology encompasses fire hazard modeling, vulnerability and exposure assessment, and in situ observations. Numerous fire hazard scenarios were tested, simulating the spatiotemporal spread of fire events under different wind characteristics. The vulnerability of the studied areas was assessed by combining population data (density and age) and building characteristics, while the exposure parameter employed land value (EUR/m2) as an indicator for qualitatively estimating potential economic effects in the study area. Field campaigns facilitated the identification and recording of critical areas and points, including high-risk buildings and population gathering areas, which subsequently informed the mitigation and fire management planning suggestions. Moreover, field recordings acted as an iterative process for validating and updating the fire risk maps. This research work utilizes state-of-the-art techniques to achieve an analysis of fire risk at a building-block level. Overall, the study presents an applied and end-to-end methodology for effectively addressing forest fire risk in peri-urban areas. [ABSTRACT FROM AUTHOR]

The prediction of wildfire spreading is necessary for managing and fighting the forest fire. The traditional models require higher accuracy of the input parameters, which is impossible in real forest fires. The paper proposed a fire-spreading model based on the dynamic data of the fire field to improve its adaptability. The model is designed using a convolutional neural network with mixed-inputs and attention mechanisms (MI-AM-CNN). It predicts the burn map after a period of time through the multiple-channel image containing terrain variables and the current burn map, and the scalars containing climate variables. The channel and spatial attention modules are integrated to handle the advanced features that contain important fire variables information and strengthen the influence of important features on the prediction. Based on the FARSITE, a large number of data sets are generated for training, validating, and testing the models in the paper. The proposed model MI-AM-CNN is compared with the state-of-the-art neural network models. Quantitative results show that MI-AM-CNN has the highest performance in predicting effectiveness and efficiency, and it can be applied recursively to get the continuous predicted results. In addition, the prediction results of MI-AM-CNN on the historical fire data demonstrate the ability of its application in the real fire case. The MI-AM-CNN can be used as a predictive method in firefighting operations, and its predicted results can provide theoretical support for the forest fire spread prediction method based on artificial intelligence. [ABSTRACT FROM AUTHOR]

This study investigates the impact of plan corner shapes on the propagation rate of fire in high-rise buildings. Employing the PyroSim fire simulation program, a systematic modeling approach was adopted to simulate fire spread in a 12-storey building with varying plan corner shapes. The findings reveal that plan corners exhibiting straight configurations devoid of protrusions or recesses exhibit a reduced risk of fire spread when contrasted with irregular shapes. Consequently, we propose the integration of regular plan shapes lacking protrusions or recesses in the design of high-rise buildings to effectively minimize the rate of fire spread. This research contribution facilitates the selection of an optimal design alternative with respect to the velocity at which fire propagates. [ABSTRACT FROM AUTHOR]

The year 2023 marks the 100th commemoration of the disastrous Kanto Earthquake in Japan, which shattered the urban fabric of Tokyo and other southern prefectures. In the years following 1923, much research into disaster risk reduction (especially fire prevention) was undertaken. This study evaluated research trends and the impact of the earthquake on the city using metropolitan population data. The following is reported: (1) This study summarized English and Japanese academic papers and reports on the Great Kanto Earthquake that have been published over the last 100 years. (2) The area of fire spread and number of damaged buildings in Tokyo due to the Great Kanto Earthquake were overwhelmingly larger than those in other areas. (3) The difference in the relative amount of damage caused by natural disasters with more than 1,000 death toll to the annual national budget in Japan became clear. (4) The Great Kanto Earthquake was the only natural disaster that caused a net worth of damage exceeding the Japanese national budget by 3.8 times. (5) The expansion of the Tokyo metropolitan area over the 100 years since the Great Kanto Earthquake was visually clarified based on demographics. (6) Today, many people live densely on soft ground, with an amplification factor of 1.8 or higher, which is 23.0% of the total population. [ABSTRACT FROM AUTHOR]

Copyright of Fire Safety Science is the property of Fire Safety Science Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Fire Safety Science is the property of Fire Safety Science Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Smoldering is slow, low-temperature, and flameless burning of porous fuel, and it is also an emerging method for energy conversion and waste removal. However, smoldering combustion is an incomplete combustion process, so the pollutions resulted from smoldering emissions are significant concerns. This work explores the flaming of emission gases from the smoldering wood chips (200 kg/m3) under different oxidizer flow velocities (4 mm/s-24 mm/s) and oxygen concentrations (14%-21%) through porous media. Once ignited on the top, the smoldering front first propagates downward (1st stage, opposed) to the bottom and then propagates upward (2nd stage, forward). We found that during the 1st-stage downward smoldering propagation, a stable flame of smoldering emissions could be piloted and sustained. The critical smoldering burning rate for maintaining a stable flame remains constant at 10–12 g/m2∙s. To reach such a minimum smoldering burning rate, the required opposed flow velocity increases from 6 to 24 mm/s, as the oxygen concentration decreases from 21 to 14%. A simplified heat transfer process is proposed to reveal the limiting conditions for the co-existence of flaming and smoldering. This work enriches strategies for the clean treatment of smoldering emissions and promotes an energy-efficient and environment-friendly method for biowaste removal. [ABSTRACT FROM AUTHOR]

The spill fires caused by liquid fuel leaks greatly threaten the safety of fuel transportation and storage. In this work, the effect of fuel temperature on the spread characteristics of flowing flames was investigated through n-butanol spilling fire experiments. The spill fire spread can be divided into three stages at different temperatures and leakage rates (I) full spread, (II) gradually extinguished spread, and (III) unable to spread. The oscillation of the flame is related to the fuel thickness and the discharge rate. As the discharge rate or temperature increases, the spread mode changes from pulsation to uniform. With an increase in temperature, the surface flow of the flame is reduced, leading to a decrease in both the preheating time and pulsation amplitude. However, the rate of liquid surface detachment from the flame increases with increasing temperature. The view factor of flame spread can be calculated by the solid flame model, and the flame influences the heat radiation spread state with stable phases or peaks. The research findings presented in this paper hold significant implications for the development of fire safety regulations pertaining to fuel leakage fires. [ABSTRACT FROM AUTHOR]

This paper presents the formulation of a novel fire spread model to allow the study of traveling fires in large open spaces. The fuel load for an office building, for example, is made up of clusters of workstations that are arranged in a realistic pattern on the floor plan. The fire begins with the assumed ignition of a single workstation. The fire dynamics are modeled using computational fluid dynamics (CFD) software, which allows the user to specify exact compartment parameters, such as the compartment size, wall lining, ventilation conditions, and fuel load distribution. To reduce computational expense, each object (e.g., workstation) is represented by a burner that has a heat release rate equivalent to a complete workstation, as determined by experimental tests. The fire is allowed to spread realistically from object to object through the use of an improved flux-time product ignition model. The improved flux-time product ignition model is derived to predict ignition under time-varying heat flux exposure and only requires well-documented material properties for implementation. The study validates the equivalent burner assumption and the flux-time product fire spread model for large compartments using experimental data from NIST (Hamins A (2005) Experiments and modeling of multiple workstations burning in a compartment. Nist Ncstar.). The proposed fire spread model for large compartments aims to provide more realistic fire behaviors for fire resistant design of structures while balancing accuracy with computational efficiency. [ABSTRACT FROM AUTHOR]

Wildfire spread models that couple physical transport and chemical kinetics sometimes simplify or neglect gas-phase pyrolysis product oxidation chemistry. However, empirical evidence suggests that oxygen (O2) is available for gas-phase and solid-phase combustion within the flaming reaction zone. This study addresses outstanding questions of O2 availability by directly measuring O2 concentrations near fuel surfaces within spreading fuel bed fires for the first time. Temporally and spatially resolved O2 concentrations within laboratory fires were investigated using uniform fuel beds of medium density fiberboard (MDF) and cardboard (CB) combs at various packing ratios (β) and angles. Minimum O2 concentration reached approximately 2–5 mol% for most fuel beds of higher β (> 0.010), while some fuel beds of low β (≤ 0.010) exhibited higher minimum O2 concentrations up to 8 mol%. Flame rate of spread, residence time, and minimum O2 were found to vary with β and were influenced by bed angle within a given β. Thermogravimetric analysis was used to assess O2 availability impacts on flaming and smoldering fuel consumption rates. Negligible impacts were observed for initially unburned fuels at ambient O2 concentrations of ≤ 10 mol%, but O2 availability had significant impacts on char oxidation rates at all tested concentrations. A one-dimensional diffusion model of O2 availability at char surfaces for near-particle O2 concentrations tested and measured in TGA and fuel bed experiments revealed a strong dependence of O2 availability on mass flux from the particle. The results of this work provide new insights regarding O2 availability and inert assumptions for fire spread models. [ABSTRACT FROM AUTHOR]

Heat and mass transfer are important processes associated with wildland fire. Both radiant and convective heat transfer are important processes with convection often being the dominant mechanism. Unlike radiation, there is no direct method of measuring convection. Since convective heat transfer is governed by the fluid flow, understanding the fluid flow provides good understanding on the convective heat transfer. In fluid mechanics, flow visualization is a common methodology used to understand flow characteristics. Schlieren imagery is a common flow visualization technique which captures changes in fluid density such as the ones occur around a fire. Background-Oriented Schlieren (BOS) is a flow visualization technique that uses a background image with various patterns to visualize the density gradient caused by density fluctuations in a fluid. We applied BOS to measure the flow associated with laboratory-scale line fires. The reproducible fires were spreading in pine needle fuel beds in a wind tunnel with and without imposed wind. This initial application of BOS in a fire environment successfully visualized the flow around the flame. The visualized flow underwent a secondary process to produce the velocity field of the flow. Results indicate that even in conditions where the fire is known to be dominated by radiation, wind carried the thermal plume ahead of the flame front and expanded the thermal plume. In contrast, in the no wind condition, the thermal plume remained vertical above the fire. Using the BOS imagery, a new model for estimation of convective heat transfer was introduced. In addition to estimation of the convective heat transfer ahead of the fire, this new model enables visualization of convective motion.

Background. Reliable wildfire prediction and efficient controlled burns require a comprehensive understanding of physical mechanisms controlling fire spread behaviour. Earlier studies explored the intermittent nature of free-burning fires, but the influence of flame intermittency on fire spread requires further attention. Aims. This research qualitatively explores dynamic fire behaviour and its influence on fire spread. Methods. Fire spread experiments were conducted under varying wind conditions inside a wind tunnel. Various cameras were used for qualitative analysis, verified against velocity and temperature measurements carried out inside the fuel bed. Key results. Dynamic fire behaviour was observed in the form of near-bed flame pulsations. These pulsations caused fluctuating contact between the flame and unburned fuel ahead of the fire front, leading to point ignitions. Under favourable heat transfer conditions, these point ignitions strengthened and merged with the existing fire front, leading to intermittent flame spread in the form of leaps. Conclusions. The transient nature of flame spread was observed during fire spread experiments conducted under steady external conditions. Implications. This research lays the foundation for critical flow and heat transfer analyses required to characterise intermittent flame spread. [ABSTRACT FROM AUTHOR]

Wildland fires are one of the most dangerous natural risks, causing significant economic damage and loss of lives worldwide. Every year, millions of hectares are lost, and experts warn that the frequency and severity of wildfires will increase in the coming years due to climate change. To mitigate these hazards, numerous deep learning models were developed to detect and map wildland fires, estimate their severity, and predict their spread. In this paper, we provide a comprehensive review of recent deep learning techniques for detecting, mapping, and predicting wildland fires using satellite remote sensing data. We begin by introducing remote sensing satellite systems and their use in wildfire monitoring. Next, we review the deep learning methods employed for these tasks, including fire detection and mapping, severity estimation, and spread prediction. We further present the popular datasets used in these studies. Finally, we address the challenges faced by these models to accurately predict wildfire behaviors, and suggest future directions for developing reliable and robust wildland fire models. [ABSTRACT FROM AUTHOR]

Property damage from wildfires occurs from spread into built‐up areas, the wildland–urban interface. Fire spread occurs as embers from one burning structure ignite neighboring ones—but mitigation reduces the chances that fire spreads. In this study, we use a simulation model with realistic parameters for a neighborhood in California to illustrate patterns of marginal benefit from mitigation. We extend existing models of fire spread in two novel ways. We show how to describe the no‐regulation equilibrium and social optimal levels of mitigation by incorporating data on a key factor, the distribution of house values in the community. We incorporate insurance in the model and show that it improves homeowner decision‐making and insurance premium regulation. The fire spread simulations show that under plausible parameter values, there is a pattern in which mitigation's marginal benefit is low at low levels of community mitigation, rises to a maximum, and then falls quickly to a low level. We argue that the maximum marginal benefit is a guide to achieving optimal mitigation in a community. Owner mitigation decisions will depend on the distribution of house values in the neighborhood and other factors. In an illustration, we use the distribution of house values in a California community to illustrate the mitigation owners will choose under independent (Nash) investment decisions, and the efficiency‐improving actions involving regulations or insurance premium subsidies that can lead to the social optimum. [ABSTRACT FROM AUTHOR]

Drones have been increasingly used in firefighting to improve the response speed and reduce the dangers to human firefighters. However, few studies simultaneously consider fire spread prediction, drone scheduling, and the configuration of supporting staff and supplies. This paper presents a mathematical model that estimates wildfire spread and economic losses simultaneously. The model can also help us to determine the minimum number of firefighting drones in preparation for wildfire in a given wild area. Next, given a limited number of firefighting drones, we propose a method for scheduling the drones in response to wildfire occurrence to minimize the expected loss using metaheuristic optimization. We demonstrate the performance advantages of water wave optimization over a set of other metaheuristic optimization algorithms on 72 test instances simulated on selected suburb areas of Hangzhou, China. Based on the optimization results, we can pre-define a comprehensive plan of scheduling firefighting drone and configuring support staff in response to a set of scenarios of wildfire occurrences, significantly improving the emergency response efficiency and reducing the potential losses.