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Background. Climate change has increased the occurrence of fire-prone weather and extreme weather events in Europe. Improving resilience of forests to reduce fire hazard has become an imperative challenge to tackle. Aims. This study aims to incorporate extreme fire events from future climate projections in developing forest planning and land management scenarios, evaluating fire risk mitigation potential. Methods. Using the wildfire--atmosphere coupled modelling system WRF-SFIRE, land management scenarios for the Lombada Forest Intervention Region (ILMA) in northeast Portugal were assessed under a business-as-usual future climate scenario. The Fire Weather Index (FWI) was used as a predictor of fire danger to select two fire events. Results. Agricultural areas can function as barrier for wildfire conditions under cooler weather. Management of the existing pine forest yielded a reduction in fire spread speed and intensity, namely in lower wind speed regimes, significantly improving suppressive capabilities. Conclusions. Fuel treatment of maritime pine performed best in reducing fire spread rate, intensity and improving suppression capability. Replacing agricultural areas with oak-based land cover can promote higher fire intensity and spread rates in the younger stanges or if left unmanaged. Implications. This framework can be used to provide additional tools for forest management across different landscapes reducing fire hazard and vulnerability and improving forest resilience, under climate change. [ABSTRACT FROM AUTHOR]

In the Mediterranean basin, coniferous reforestation mainly comprises forest stands highly susceptible to fires. When silvicultural treatments have not been performed for decades after plantation, these stands often exhibit high vertical and horizontal tree density, along with a significant occurrence of lying and standing deadwood, thereby increasing the fuel load. On average, these pine forests are characterized by high values of above-ground biomass, ranging from 175 to 254 Mg ha−1 for the younger and the older ones, respectively. The theoretical heat energy produced per surface unit, in the case of the total combustion of the above-ground biomass, is also high, varying from 300 to 450 MJ ha−1 depending on the stage of stand development. In this study, we demonstrated the importance of silvicultural interventions in reducing the pyrological potential in pine reforested stands located in southern Italy, also giving attention to the water savings needed during extinction phases. In detail, we applied a preliminary mathematical reaction-diffusion model aimed at predicting the development of forest fires. The model was applied using data obtained through the estimation of the pyrological potential in terms of heat energy produced per surface unit (1 hectare) and the variation in the critical surface intensity. We verified that, when silvicultural interventions are applied, they induce a reduction of heat energy ranging between 17 and 21%, while the extinguishing water saved ranges between 600 and 1000 Mg ha−1. Moreover, when the silvicultural interventions are implemented, the probability of the transition from surface fire to crown fire can be reduced by up to 31%. The most effective results on fire risk mitigation are mainly obtained when thinning aimed at reducing canopy and tree density is carried out in the younger phases of the reforested pine stands. [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]

The object of this study is the process of fire propagation through the surface of external wall structures with facade thermal insulation. The paper examines the influence of facade parameters and the width of a fire-proof eaves on preventing the spread of fire by external vertical structures using the example of a residential building. With the use of FDS modeling, the relationships between the parameters of external enclosing structures and the fire-proof eaves on the processes of limiting the spread of fire were investigated. The influence of the minimum parameters of the height of the inter-floor windowsill in the absence of a fire-proof eaves on the spread of fire was determined. The dependence of temperature change near the surface of the facade on the width of the fire-proof eaves and the height of the window between floors was established. Based on a series of simulated experiments, it was established that with a height of 1.0 m between floors and the absence of a fire-proof eaves, the critical temperature value is 250 °C. This value corresponds to the destruction temperature of a standard metal-plastic window structure. For the case when the wall height is 1.0 m, and the width of the fire-proof eaves is 0.75 m, the temperature value is 180 °C. That is, the safety condition of 250 °C is met. Based on the research, a dependence was found on the criterion of not exceeding the critical temperature of 250 °C at the level of 1.4 m of the facade of the building floor located above the fire floor. The criterion holds when the width of a fire-proof eaves is at least 0.4 m and the height of the window partition is 1.0 m, as well as when the width of the eaves is 0.5 m, and the height of the window partition is 0.6 m. It was established that the height of a window interfloor partition has a smaller effect than the width of the fire-proof eaves that separates the floors that are located above. [ABSTRACT FROM AUTHOR]

Modeling and understanding of underground coal fire is of significance for green-and-safe mining of coal resources in China. Two issues remain unsolved in forward-propagation models of underground coal smoldering fires: one-step coal oxidation has been too simple so that endothermic reactions such as water evaporation and pyrolysis that have important influence on smoldering propagation of underground coal fires have been not considered; and models have not been validated via experimental data. In this work, a three-step chemical reaction scheme including water evaporation, coal pyrolysis, and char oxidation was employed and mathematic model in terms of forward propagation of underground coal smoldering fires was established. The theoretical model was numerically calculated using COMSOL Multiphysics finite element software. The theoretical model was numerically calculated using COMSOL Multiphysics finite element software, and the forward smoldering spread experiment of underground coal fire driven by thermal buoyancy under different ground crack permeability conditions was carried out. Comparison experiment and numerical calculation were carried out. Results show that the proposed model not only owns good capability to predict the peak temperature and velocity of smoldering propagation of underground coal fire, but also can inversely plot multiple step chemical reactions as well as spatiotemporal evolutions of oxygen and solid species mass fractions. In addition, the controlling mechanism of smoldering propagation of underground coal fires was further revealed.

Globalization impacts directly pollution, and one of the side effects is the increasing number of forest fires and their fast propagation. To reduce this phenomenon, several studies have tried to model fire propagation and find an adequate method to predict (or follow) this spread to stop it. However, to the best of our knowledge, most of the developed works do not use an adaptive exploration strategy to follow the fire evolution. Instead, they are mainly focused on observing the evolution and trying to find an adequate spread model to predict fire behavior. Due to the lack of all the exact parameters to predict the fire spread, in this paper, we propose a new exploration strategy based on reinforcement learning using an Unmanned Aerial Vehicle (UAV). The learned exploration strategy is able to predict and follow the fire propagation. To follow the generated waypoints by the exploration strategy, we develop a new robust controller, which can be embedded in a UAV. All these modules are encapsulated and interact with each other using a synchronized architecture. To prove the efficiency of our proposal, we present the obtained results on several simulated forest fire scenarios and compare them with other approaches. Then, We validate our entire architecture and show its efficiency using software in the loop environment using the Robot Operating System (ROS). [ABSTRACT FROM AUTHOR]

Background. Wildfires are becoming more severe, so we need improved tools to predict them over a wide range of conditions and scales. One approach towards this goal entails the use of coupled fire/atmosphere modelling tools. Although significant progress has been made in advancing their physical fidelity, existing tools have not taken full advantage of emerging programming paradigms and computing architectures to enable high-resolution wildfire simulations. Aims. The aim of this study was to present a new framework that enables landscapescale wildfire simulations with physical representation of combustion at an affordable cost. Methods. We developed a coupled fire/atmosphere simulation framework using TensorFlow, which enables efficient and scalable computations on Tensor Processing Units. Key results. Simulation results for a prescribed fire were compared with experimental data. Predicted fire behavior and statistical analysis for fire spread rate, scar area, and intermittency showed overall reasonable agreement. Scalability analysis was performed, showing close to linear scaling. Conclusions. While mesh refinement was shown to have less impact on global quantities, such as fire scar area and spread rate, it benefits predictions of intermittent fire behavior, buoyancy-driven dynamics, and small-scale turbulent motion. Implications. This new simulation framework is efficient in capturing both global quantities and unsteady dynamics of wildfires at high spatial resolutions. [ABSTRACT FROM AUTHOR]

Forest fires are becoming a more significant problem in Central Europe, but their danger is not as high as that in Southern Europe. The exception, however, is forest fires occurring in disturbed areas (windthrow and bark beetle outbreak areas), which are comparable in severity and danger to the most serious forest fires. In this study, we describe the current situation in Central European countries in terms of fire protection for disturbed areas in managed forests and forest stands left to spontaneously develop (secondary succession). If a country has regulations and strategies in this area, they are often only published in the local language. In this review, we combine information from all Central European countries and summarize it in a unified international language, provide an opportunity for local authorities to express their own experiences, and integrate data from worldwide scientific research. Thus, this paper may be considered a universal guide for managing fire protection and preparedness in disturbed areas and can serve as a reference for the establishment of strict legislative rules at the state level. These laws must be obligatory for all stakeholders in individual countries. The motivation for this study was two large forest fires in an area left to spontaneously develop in the Bohemian Switzerland National Park in the Czech Republic and Harz Mountains in Germany in the summer of 2022. These incidents revealed that fire prevention legislation was inadequate or nonexistent in these areas. The strategy of the European Union is to increase the size of protected areas and spontaneous development areas. Therefore, we consider it necessary to provide governments with relevant information on this topic to create conditions for better management of these destructive events. [ABSTRACT FROM AUTHOR]

Copyright of Ciência Florestal (01039954) is the property of Ciencia Florestal 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.)

Fire safety is one of the major concerns in the public transport and thus passenger trains in the UK seek continuous improvement in passenger safety and comfort. In order to combat fire, there is a legal requirement in most countries across the global to install a fire suppression system within passenger railroad cars. In the event of fire, the thermal sensors trigger high pressure flow of hydrant through nozzles into the railroad car, thus supressing the fire. The efficient design of fire suppression system is highly dependent on the operational parameters of the system. The published literature, although abundant in investigating the flow characteristics through nozzles, severely lacks in conjugating this with fire suppression. Thus, in the present study, extensive parametric investigations have been carried out on the operational and design parameters of a conventional fire suppression system using an integrated approach i.e., hydrant flow and combustion. Advanced numerical techniques have been employed to evaluate the hydrodynamic characteristics of the fire suppression system based on the size of droplets of the hydrant from exiting the nozzles and the flow rate of the hydrant. The effects of these parameters on the temperature and the concentration of soot particles within the passenger railroad car have been evaluated. The results show that smaller sized hydrant droplets (250um) are more effective in supressing the fire in enclosures compared to larger droplets (750um), while higher flow rates tend to supress the fire more efficiently. It is envisaged that the results obtained in the present study will help in developing more efficient fire suppression systems for passenger railroad cars. [ABSTRACT FROM AUTHOR]

A stochastic model motivated by the Lagrangian transported probability density function method for turbulent reacting flows and the cellular automata approach for forest fires was put together to simulate propagation of fires in terrains with inhomogeneous composition. In contrast to the usual cellular automata models for fires where the probability of ignition is prescribed, here the ignition of cells is determined by a random walk that mimics turbulent convection and diffusion of the hot gases and firebrands from upwind and neighbouring fire fronts. Radiation is also included. The model is aimed at speed of computation while approximating the key physics through only a few terrain-related inputs and tunable parameters representing fire intensity, hot gas and ember decay timescales, cell ignition delay and local turbulence. These parameters were calibrated against controlled fire experiments and the model was then used to give reasonable predictions for fires of increasing complexity. The presented framework allows improvements for more accurate representation of the flammable material characteristics, fire-induced flow modifications, and most other phenomena present in fires, hence providing an extendable and simple yet physically-realistic novel modelling approach. [ABSTRACT FROM AUTHOR]

A large amount of storage may cause large-scale fire or explosion accidents due to the potential fire risk of lithium-ion batteries, which poses a great threat to the safety of personnel and property. In this study, the fire model of an individual cell is established according to the experimental data and the relevant parameters of thermal runaway simulation of large capacity battery are determined. The battery pack model is established according to the real setting of a warehouse. The fire characteristics of the battery pack spreading around in the warehouse environment are studied. The results show that the fire of lithium-ion batteries is preferentially diffused to the upper battery pack in the warehouse environment, and spread to the upper battery pack 19 s after the initial battery thermal runaway. The fire propagation of the horizontal battery pack is greatly affected by the distance. The farther the battery string is from the thermal runaway battery, the later the fire propagation battery string occurs. Furthermore, the role and effect of battery pack spacing, fire warning and automatic sprinkler system in fire are provided, so as to carry out better research on the storage safety of lithium-ion battery warehouses. [ABSTRACT FROM AUTHOR]

The interaction of wind and fire on a sloped terrain is always complex owing to the mechanisms of heat transfer and flame dynamics. Heating of unburned vegetation by attached flames may increase the rate of spread. The relative intensities of convective and radiative heat fluxes may change fire behaviour significantly. This paper presents a detailed analysis of flame dynamics, mode of fire propagation and surface radiative and convective heat fluxes on sloped terrain at various wind speeds using physics-based simulations. It was found that with increasing slope angles and wind velocity, the plume inclines more towards the ground and becomes elongated in upslope cases, whereas in downslope cases, the plume rises from the ground earlier. For higher wind velocities, the flame and near-surface flame dynamics appear to show rising, even though the plume is attached. The flame contour results indicate that the near-surface flame dynamics are difficult to characterise using Byram's number. A power-law correlation was observed between the simulated flame lengths and fireline intensities. The convective heat fluxes are more relevant for wind-driven fire propagation and greater upslopes, whereas both fluxes are equally significant for lower driving wind velocities compared with higher wind velocities. A physics-based study of grassfire behaviour over flat and sloped (upslope and downslope) terrain at field scale with varying wind velocities is presented. The flame dynamics, mode of fire propagation and surface radiative and convective heat fluxes are analysed. [ABSTRACT FROM AUTHOR]

Summary: The serious fire incident at Grenfell Tower in London, involving a combustible façade system that was installed as part of a major refurbishment of the building, has raised concerns regarding the fire risk that these systems pose. The fire spread over the façade of the Tower was previously numerically modelled and this model was validated by comparison with observational data. This model was used to determine the fire behavior of the façade and the fire's propagation into apartments through windows. In the present paper, impact models are used to evaluate tenability conditions inside the Tower, especially for the apartments in the first corner of the Tower that caught fire. The source of toxic effluents includes the components used in the refurbishment of the façade and the apartment furniture. Different hypotheses of gas yields are tested to assess variability and unknowns in the burning conditions. An extensive literature review was conducted to investigate the toxic yields to be considered in the simulations. Tenability conditions are assessed for each apartment during the fire spread over the façade. This leads to the quantification of the thermal and toxic environment inside the apartments. Two different models are tested for thermal and toxic threats, and the influence of the insulation material used in the façade is investigated. The results showed that the same conclusion can be made regardless of the input data for toxicity and the model used, within the limits of the studied dataset and conditions. Fires from the apartments quickly drive tenability conditions, independently of the dataset and model used, and even if mineral wool is used instead of poly‐isocyanurate as façade insulant. [ABSTRACT FROM AUTHOR]

Summary: The recent dramatic events at Grenfell Tower in London involving a combustible façade system have raised concerns regarding the fire risk that these systems pose. The spread of fire over the façade of the Tower was previously modelled numerically and the results of this modelling were validated by comparison with observations of the real fire. This model was used to determine the fire behaviour of the façade and the propagation of the façade fire into the apartments through windows. The modelling used an impact model according to ISO 13571 and included fire loads from the façade and, when relevant, from apartment contents. Tenability levels inside the apartments were quantified by an analysis of the toxic and thermal conditions due to the combustion of the façade materials and the apartment contents. In the present paper, the conditions inside the lobbies and stairs of the Tower are investigated, building on the previous analysis of the apartments. This allows an understanding of the evolution of toxic and thermal conditions whilst the fire spread, and their impact on egress during the fire event. [ABSTRACT FROM AUTHOR]

Forest fires are becoming a more significant problem in Central Europe, but their danger is not as high as that in Southern Europe. The exception, however, is forest fires occurring in disturbed areas (windthrow and bark beetle outbreak areas), which are comparable in severity and danger to the most serious forest fires. In this study, we describe the current situation in Central European countries in terms of fire protection for disturbed areas in managed forests and forest stands left to spontaneously develop (secondary succession). If a country has regulations and strategies in this area, they are often only published in the local language. In this review, we combine information from all Central European countries and summarize it in a unified international language, provide an opportunity for local authorities to express their own experiences, and integrate data from worldwide scientific research. Thus, this paper may be considered a universal guide for managing fire protection and preparedness in disturbed areas and can serve as a reference for the establishment of strict legislative rules at the state level. These laws must be obligatory for all stakeholders in individual countries. The motivation for this study was two large forest fires in an area left to spontaneously develop in the Bohemian Switzerland National Park in the Czech Republic and Harz Mountains in Germany in the summer of 2022. These incidents revealed that fire prevention legislation was inadequate or nonexistent in these areas. The strategy of the European Union is to increase the size of protected areas and spontaneous development areas. Therefore, we consider it necessary to provide governments with relevant information on this topic to create conditions for better management of these destructive events.

The suggestion has been made within the wildland fire community that the rate of spread in the upper portion of the fire danger spectrum is largely independent of the physical fuel characteristics in certain forest ecosystem types. Our review and analysis of the relevant scientific literature on the subject suggest that fuel characteristics have a gradual diminishing effect on the rate of fire spread in forest and shrubland fuel types with increasing fire danger, with the effect not being observable under extreme fire danger conditions. Empirical-based fire spread models with multiplicative fuel functions generally do not capture this effect adequately. The implications of this outcome on fire spread modelling and fuels management are discussed. [ABSTRACT FROM AUTHOR]

High complexity and growing interdependencies of chemical and process facilities have made them increasingly vulnerable to domino effects. Domino effects, particularly fire dominoes, are spatial-temporal phenomena where not only the location of involved units, but also their temporal entailment in the accident chain matter. Spatial-temporal dependencies and uncertainties prevailing during domino effects, arising mainly from possible synergistic effects and randomness of potential events, restrict the use of conventional risk assessment techniques such as fault tree and event tree. Bayesian networks—a type of probabilistic network for reasoning under uncertainty—have proven to be a reliable and robust technique for the modeling and risk assessment of domino effects. In the present study, applications of Bayesian networks to modeling and safety assessment of domino effects in petroleum tank terminals has been demonstrated via some examples. The tutorial starts by illustrating the inefficacy of event tree analysis in domino effect modeling and then discusses the capabilities of Bayesian network and its derivatives such as dynamic Bayesian network and influence diagram. It is also discussed how noisy OR can be used to significantly reduce the complexity and number of conditional probabilities required for model establishment.

• Determining the equations of wavefronts and wave rays by Randers geodesics. • Providing the model of wildfire propagation by Huygens' principle. • Determining the paths through them the fire reaches a special place. • Determining the paths through which the fire spreads faster. Here, by using the validity of the Huygens' envelope principle for wavefronts in Randers spaces, we present some models for wildfire propagation in a flat land under the presence of wind. The wind could be constant or space-dependent. In the models, the height of the propagation is considered, trajectories of fire particles are tracked, and the equations that give the wavefront at each time are provided. Furthermore, we determine the paths of great importance in the process of wildfire management, called strategic paths. These paths can be used to determine the locations of barriers that we make to block the fire and stop it from propagation toward some special area; or to determine the paths through which the fire surrounds, for instance, the transmission lines of the power system. Finally, we provide several interesting examples of spreading the wildfire with different conditions. We implement the examples in the MATLAB environment to solve and provide the models of fire propagations. [ABSTRACT FROM AUTHOR]

An analysis of a dataset (n = 58) of high-intensity wildfire observations in cured grasslands from southern Australia revealed a simple relationship suitable for quickly obtaining a first approximation of a fire's spread rate under low dead fuel moisture contents and strong wind speeds. It was found that the forward rate of fire spread is approximately 20% of the average 10-m open wind speed. The data on rate of fire spread and 10 m open wind speed ranged from 1.6 to 17 and 20 to 62 km h−1, respectively. The validity of the resulting rule of thumb was examined across a spectrum of burning conditions and its performance was contrasted against that of established empirical-based fire spread models for three different grassland fuel conditions currently used operationally in Australia. The 20% rule of thumb for grassfires produced error statistics comparable to that of the fire spread rate model for grazed or cut grass fuel conditions as recommended for general use during the summer fire season in southern Australia. [ABSTRACT FROM AUTHOR]

Thirty-one bush fire experiments are used to assess the predictive capability of a bush fire spread model. This model has been optimized by a deterministic method of parameter calibration. The experiments used were carried out each year from 2014 to 2017 in a forest–savannah transition zone. The characteristics of the herbaceous stratum as well as the meteorological and topographical data are well documented. The characteristics of the fire have also been measured to understand the behaviour of the fire in a Guinean savannah. The predicted rate of fire spread and fire contours gave results in good accordance with those of the experiments.

In mathematics, forest fires are mainly described by the fire spread model. The model analyzes the tree-to-tree (T2T) spread of the fire, providing the optimal solution for rescuers. This paper aims to develop a forest fire rescue strategy based on variable extinguishing rate (VER). Firstly, a dynamic model was established for the T2T propagation of forest fire. Then, the classic forest fire rescue strategy was improved to adapt to the changing extinguishing rate of trees. Finally, the improved strategy was proved correct and rational through simulation. Our forest fire rescue strategy can adjust dynamically to the tree state and rescue rate. The best rescue rate of forest fire was obtained in the equilibrium state of fire propagation. The research results help to minimize the damage and rescue cost of forest fire.

To fight against forest fires, simple and improved models are more searched out due to the fact they are more easily understandable by the users. This actual model is part of the fire propagation models within a network. It is simple and easy to implement. However, it depends on several parameters that are difficult to measure or estimate precisely beforehand. The prediction by this model is therefore insufficient. A deterministic optimization method is introduced to calibrate its parameters. The optimized model was tested on several laboratory experiments and on two large-scale experimental fires. The comparison of the model results with those of the experiment shows a very significant improvement in its prediction with the optimal parameters.

Scholars and scientists have been making efforts to discover ways to control and lessen the resonance of concurrent fires such as forest fires, and various space fires; however, no potential solutions have been concluded from their studies so far. The origin of these types of fires concerns the unstable nature of the flames and the considerable unpredictability associated with them. This work led us to do proper experimentation for the effect of sound on the spreading of the flames. Sound energy as a wave is always accompanied by compression and rarefaction. As an external effect, sound in the immediate vicinity of spreading flame can affect the flame spread rates. Appreciable work had been carried out however; the effect of sound on flames in a purely natural convective environment is an aspect yet to be thoroughly understood. Flame spread rate is a direct indication of forwarding heat transfer from burning to non-burning region. Formation of localized pressure and velocity fields occurs around the pilot fuel by the presence of sound waves. Change in heat transfer may results in increment or decrement in spread rates, when compared with one without sound. The present work attempts physical insight into the effect of sound frequency of intermediate range (3500 Hz to 7500Hz) on the spreading of flames in different configurations coupled with external sources. Results advocate the noteworthy impact of acoustics on the fire propagation phenomenon in distinct modes. Experimentation have revealed that acoustics has a critical influence on fire propagation, reducing the spread rate by 100 percent in a unilateral configuration. [ABSTRACT FROM AUTHOR]

High temporal resolution information on burnt area is needed to improve fire behaviour and emissions models. We used the Moderate Resolution Imaging Spectroradiometer (MODIS) thermal anomaly and active fire product (MO(Y)D14) as input to a kriging interpolation to derive continuous maps of the timing of burnt area for 16 large wildland fires. For each fire, parameters for the kriging model were defined using variogram analysis. The optimal number of observations used to estimate a pixel's time of burning varied between four and six among the fires studied. The median standard error from kriging ranged between 0.80 and 3.56 days and the median standard error from geolocation uncertainty was between 0.34 and 2.72 days. For nine fires in the south-western US, the accuracy of the kriging model was assessed using high spatial resolution daily fire perimeter data available from the US Forest Service. For these nine fires, we also assessed the temporal reporting accuracy of the MODIS burnt area products (MCD45A1 and MCD64A1). Averaged over the nine fires, the kriging method correctly mapped 73% of the pixels within the accuracy of a single day, compared with 33% for MCD45A1 and 53% for MCD64A1. Systematic application of this algorithm to wildland fires in the future may lead to new information about vegetation, climate and topographic controls on fire behaviour. © IAWF 2014.

Summary: Flame retardant cable coatings are applied to grouped electrical cables as a passive protection means to reduce the fire hazard. This work studied the flammability of cable coatings and developed a fire test method to evaluate the fire propagation propensity of grouped cables protected by cable coatings. Firstly, ignition tests of 12 cable coatings were conducted and showed that all cable coatings are ignitable. Secondly, three selected cable coatings and a cable bandage, as an alternative passive protection method, were evaluated along with two types of electrical cables in ASTM E‐2058/ISO 12136 by measuring the fire propagation index (FPI). The FPI values of coated cables do not demonstrate a monotonous change relative to the FPI of uncoated cables, and the FPI trend is cable dependent. Thirdly, two selected cable coatings and a cable bandage were further examined in the 2.4‐m parallel panel fire test (PPT) along with an electrical cable with an FPI value of 30 (m/s1/2)/(kW/m)2/3. The cables coated by both tested cable coatings showed fire propagation while the bandaged cables did not propagate. The consistent fire propagation propensities between the PPT and small‐scale fire tests support using the FPA tests to examine the flammability of cable coatings. [ABSTRACT FROM AUTHOR]

An analysis of a dataset (n = 58) of high-intensity wildfire observations in cured grasslands from southern Australia revealed a simple relationship suitable for quickly obtaining a first approximation of a fire’s spread rate under low dead fuel moisture contents and strong wind speeds. It was found that the forward rate of fire spread is approximately 20% of the average 10-m open wind speed. The data on rate of fire spread and 10 m open wind speed ranged from 1.6 to 17 and 20 to 62 km h−1, respectively. The validity of the resulting rule of thumb was examined across a spectrum of burning conditions and its performance was contrasted against that of established empirical-based fire spread models for three different grassland fuel conditions currently used operationally in Australia. The 20% rule of thumb for grassfires produced error statistics comparable to that of the fire spread rate model for grazed or cut grass fuel conditions as recommended for general use during the summer fire season in southern Australia.

In mathematics, forest fires are mainly described by the fire spread model. The model analyzes the tree-to-tree (T2T) spread of the fire, providing the optimal solution for rescuers. This paper aims to develop a forest fire rescue strategy based on variable extinguishing rate (VER). Firstly, a dynamic model was established for the T2T propagation of forest fire. Then, the classic forest fire rescue strategy was improved to adapt to the changing extinguishing rate of trees. Finally, the improved strategy was proved correct and rational through simulation. Our forest fire rescue strategy can adjust dynamically to the tree state and rescue rate. The best rescue rate of forest fire was obtained in the equilibrium state of fire propagation. The research results help to minimize the damage and rescue cost of forest fire. [ABSTRACT FROM AUTHOR]

Summary: The tragic events at Grenfell Tower in 2017, involving a combustible façade system, have raised concerns regarding the fire risk that these systems pose. In this series of articles, so far published, fire development inside the initial apartment has been investigated using an appropriate computational fluid dynamics (CFD) model. Several scenarios including different fire sources and ventilation conditions were addressed. Fire propagation through the window to the external façade and to higher apartments was modelled. This model was validated by comparing the numerical results with the visual observations reported in the Grenfell Inquiry. A CFD model of the complete east face of the Grenfell Tower was then created. This paper details CFD modelling of the complete Grenfell Tower façade during the late horizontal phase of fire spread. As the physics of lateral flame spread is different from that for upward flame spread, it is important to assess the validity of the model, thus far developed, for this configuration. Fire propagation over the whole façade is modelled and compared with observations from the real disaster. This provides a better understanding of its fire behaviour and of the contribution of architectural details and their impact on fire spread. [ABSTRACT FROM AUTHOR]

Copyright of Military Engineer / Hadmérnök is the property of National University of Public Service 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.)

Summary: The dramatic event of the Grenfell Tower in 2017 reminds the importance of addressing fire issues as a whole and clearly highlighted one of the major roles played by the façade as fire propagation vector. To understand and analyse this disaster, numerical simulation allows particular phenomena to be evaluated more easily. The numerical model addressed for the fire behaviour of the façade system was developed using a multiscale approach and validated at different scales. In this paper, the fire behaviour of the façade and of its window frames is addressed. A computational fluid dynamics (CFD) model is used to investigate the fire spread from the initial apartment to the overall façade with different scenarios for the fire source and ventilation. Fire propagation through windows to the façade and to upper apartments is addressed. General curves representing the re‐entry of flames into upper apartment are extracted from simulations. The numerical results are validated by comparison with observations from videos and pictures of the real fire. Numerical results show that whatever the initial fire location and ventilation conditions, even if the fire source is of hundreds kilowatts, it is enough to ignite the adjacent element early and to the appearance of external flames shortly after. [ABSTRACT FROM AUTHOR]

Summary: The dramatic event of the Grenfell Tower (June 2017), involving a combustible façade system, has raised concerns regarding the fire risk that these systems address. Indeed, as façades are complex systems, it is not straightforward to assess which part of the system is involved in the global fire behaviour. Understanding such façade fires is thus very complex as it depends on a combination of various products and system characteristics, including window frames or air gap or cavity barriers. Fire development inside the initial apartment was investigated using an appropriate CFD model with different scenarios for the fire source and ventilation conditions in a previous study. Fire propagation through the window to the external façade and to higher apartments was modelled and validated against visual observations. This paper describes CFD modelling of the complete Grenfell tower facade, and investigates vertical fire spread behaviour over the full height façade from the initial apartment. Contributions from the combustion of all the apartments' furniture, depending on window failure, and architectural details of the refurbished façade are considered in the numerical model. The modelling results are validated by comparison with photographic and video observations of the real fire. [ABSTRACT FROM AUTHOR]

Most recorded Libya house fire accidents are associated with the types of roofing materials used in the building of the traditional Libya houses, mainly from the date palm trees (DPT) parts. This research focuses on the fire characteristic properties of DPT building material based on four conducted laboratory experiments on the preprocessed known mass of leaves, trunk, and root samples collected across 40, 41, 80, and 81 years old trees, across different geographical location in Libya. The characterisation analyses result of calorific energy contribution of 4107.2 cal/gram from older DPT trunk samples, percentage weight loss reduction of -2.2 mg / ᵒC, at the highest temperature range of 727- 899 ᵒC from thermogravimetric test. The highest diffusivity rate of 0.138 mm2 /s also occurs at 99–100 ᵒC on the oldest trunk sample, and fire propagation index of 0.0463 was recorded with index performance of 32.3 ᵒC. These result analyses indicated high heat conductivity at a lower temperature, fast heat rate of propagation to support fire accident when in contact with fire flame, and high calorific load value for fire growth in traditional Libya houses. Useful information on rate of heat conductivity, fire propagation properties, and thermal behaviours of DPT for fire impact assessment analyses prediction in traditional Libya houses.

This work provides a detailed overview of existing investigations into the fire–wind interaction phenomena. Specifically, it considers: the fanning effect of wind, wind direction and slope angle, and the impact of wind on fire modelling, and the relevant analysis (numerical and experimental) techniques are evaluated. Recently, the impact of fire on buildings has been widely analysed. Most studies paid attention to fire damage evaluation of structures as well as structure fire safety engineering, while the disturbance interactions that influence structures have been neglected in prior studies and must be analysed in greater detail. In this review article, evidence regarding the fire–wind interaction is discussed. The effect of a fire transitioning from a wildfire to a wildland–urban interface (WUI) is also investigated, with a focus on the impact of the resulting fire–wind phenomenon on high- and low-rise buildings.

Summary: The recent fire events in buildings involving combustible cladding systems have raised concerns regarding the risk that these systems can pose. Understanding such facade fires is complex as they involve a combination of various products and system. Facade fire propagation tests at ISO 13785‐1 intermediate scale were performed on different combinations of aluminium composite material (ACM) claddings and insulants. Simulations were addressed to reproduce these tests and were validated in terms of thermal conditions in the system. This allowed additional investigation and understanding of fire propagation on the facade and more accurate determination of the fire behaviour of the overall system. In this paper, the scaling influence on the fire behaviour of ACM clad systems is investigated with simulations performed to reproduce fire tests at the BS8414‐1 larger scale on three different combinations of ACM and insulants. The contributions of the cladding and insulant were numerically investigated. The fire behaviour of each component and of the overall system is validated by comparison with experiments. Simulations and tests show that the ACM cladding is the most important element driving the global fire behaviour of the systems. In particular, ACM‐PE‐based cladding systems, whatever the insulant, show extensive fire propagation while its degradation affects the integrity of the cavity. [ABSTRACT FROM AUTHOR]

Summary: Increasing the energy performance of buildings is a crucial sustainable development objective. However, building features, products, mounting, and fixing of façade components have a large impact on fire safety. Authors in previous study performed façade fire propagation tests according to ISO13785‐1 on different combinations of ACM claddings and insulants. In this paper, simulations are performed to reproduce three of these tests. The model is validated with the aforementioned experimental results, including details in terms of thermal conditions in the system. This allows better understanding of the fire propagation on the overall system. Additional information, such as the relative contribution of the cladding and the insulant, are investigated numerically. The fire behaviour of each component of the overall system is thus validated. Simulations and tests performed show that the ACM cladding is the most important element driving the global fire behaviour of façade types considered. In particular, ACM‐PE–based cladding systems show large fire propagation whatever the insulant. This series of simulations is a part of a larger study including several steps of increasing complexity. Once the model for the fire behaviour of façade system is validated at intermediate scale, larger façade systems will be investigated numerically to evaluate the influence of scaling. [ABSTRACT FROM AUTHOR]

Thermal runaway (TR) and the resulting fire propagation are still critical issues puzzling the application of lithium-ion batteries in energy storage system (ESS). A fire propagation model including accurate TR propagating process assists in understanding the battery failure mechanism and determining the safety-optimal design of ESS, while its development is hindered by the complexity of simulating large-scale spatial system and interactions between TR and fire. In this work, a coupled semi reduced-order model (SROM) toward real-scale ESS is developed to capture battery TR and fire propagation behavior. Wherein, meshless methods are implemented for battery cluster by constructing thermal resistance network to simulate heat generation and transfer, which simultaneously couples a mass flowing network to address gas generation and subsequent jet. Full-order CFD model is adopted to simulate burning behavior in external fluid with higher precision. This model can accurately capture cross-scale parameters, including temperature evolution at cell-level and heat release rates (HRR) at system-level, as confirmed by experiments. Simulation results elucidate the failure propagation mode and mechanism from cell-to-cell to module-to-module levels. The significant impact of triggering position on fire behavior is also revealed that TR originating from the cluster center causes rapider fire growth and larger peak HRR during fire propagation. The SROM covers entire phenomena chain from cell-level to system-level, which can serve as new guidelines for designing and running safer ESS. • A semi reduced-order model for fire propagation of lithium-ion battery is proposed. • Model balances fidelity and efficiency of battery simulation at large-scale system. • Model covers entire event chain of thermal runaway from cell-level to system-level. [ABSTRACT FROM AUTHOR]

Live Fuel Moisture Content (LFMC) contributes to fire danger and behavior, as it affects fire ignition and propagation. This paper presents a two layered Landsat LFMC product based on topographically corrected relative Spectral Indices (SI) over a 2000–2011 time series, which can be integrated into fire behavior simulation models. Nine chaparral sampling sites across three Landsat-5 Thematic Mapper (TM) scenes were used to validate the product over the Western USA. The relations between field-measured LFMC and Landsat-derived SIs were strong for each individual site but worsened when pooled together. The Enhanced Vegetation Index (EVI) presented the strongest correlations (r) and the least Root Mean Square Error (RMSE), followed by the Normalized Difference Infrared Index (NDII), Normalized Difference Vegetation Index (NDVI) and Visible Atmospherically Resistant Index (VARI). The relations between LFMC and the SIs for all sites improved after using their relative values and relative LFMC, increasing r from 0.44 up to 0.69 for relative EVI (relEVI), the best predictive variable. This relEVI served to estimate the herbaceous and woody LFMC based on minimum and maximum seasonal LFMC values. The understory herbaceous LFMC on the woody pixels was extrapolated from the surrounding pixels where the herbaceous vegetation is the top layer. Running simulations on the Wildfire Analyst (WFA) fire behavior model demonstrated that this LFMC product alone impacts significantly the fire spatial distribution in terms of burned probability, with average burned area differences over 21% after 8 h burning since ignition, compared to commonly carried out simulations based on constant values for each fuel model. The method could be applied to Landsat-7 and -8 and Sentinel-2A and -2B after proper sensor inter-calibration and topographic correction.

Inspired by a serious fire accident on the cable-stayed bridge, the characteristics of this type of cable fire were investigated pertinently with experiment. And some important parameters, such as temperature distribution and flame height, were measured. The behaviors of fire growth and fire propagation were analyzed; furthermore, fire spread rate was obtained. Additionally, the effectiveness of fire extinguishing methods used in such cable fires was also examined. The results show that the special cables layout and material composition seriously influenced fire behaviors. When internal steel strands were ignited, the polyethylene material on its surface would melt and drop at high temperature, causing that external burning drops penetrated into the interior, which could gradually ignite the unburned part and flaring up the fire. The HDPE sheath originally as a protected component, once ignited, would generate a large amount of burning molten drops, dramatically promoting the fire development to the underneath cable. As observed in fire extinguishing experiments, dry powder, one method recommended by NFPA, showed a re-ignition phenomenon. By comparison, water, one method deprecated in standard, contrarily brought about good effects in fire extinguishing due to an effective cooling effects for inner steel. [ABSTRACT FROM AUTHOR]

The prediction of fire propagation across landscapes is necessary for safe and effective fire management. We analyzed the predictive accuracy of models currently used operationally in Australia for predicting fire spread rates in five different fuel types (grasslands, temperate and semi-arid shrublands, dry eucalypt and conifer forests) compared to their previous counterparts. We calculated error statistics and contrasted model predictions against observed spread rates of field observations of wildfires and prescribed fires. We then compared the changes in error metrics of older models to newer ones. Evaluation results show newer models to have improved prediction accuracy. Mean absolute errors were reduced by 56%, 68% and 70% in dry eucalypt forests, grasslands and crown fires in conifer forests, respectively. The most significant improvement was the reversion of under-prediction bias achieved with newer models. This study has highlighted the value of continuous improvement when it comes to developing operational wildland fire spread models. [ABSTRACT FROM AUTHOR]