Fire, Volume 6, Issue 1 (January 2023) – 35 articles

Appropriate estimates of ignition frequency derived from fire statistics are crucial for quantifying fire risks, given that ignition frequency underpins all probabilistic fire risk assessments for buildings. Rahikainen et al. (Fire Technol 2004; 40:335–53) utilized the generalized Barrois model to evaluate ignition frequencies for different buildings in Finland. The Barrois model provides a good prediction of the trend of the ignition frequency; however, it can underestimate the ignition frequency depending on the building type. In this study, an analysis of the Australian fire statistical data from 2012 to 2019 was performed and compared with studies from Finland. A new coefficient is proposed to improve the Barrois model for a better fit for buildings in Australia. Several categories, such as hotels and hospitals, which were absent in previous studies, have been included as separate categories in this study. Office and retail spaces in Finland have an ignition frequency one order of magnitude lower than in Australia. On the other hand, other buildings (retail and apartments in particular) are much more prone to fire ignition in Australia than in Finland. The improved generalized Barrois model based on the Australian fire statistical data will be useful for determining ignition frequency for risk quantification in the Australian context. Full article

Wildfires simplify ecosystems, modifying the ecological niches of the fauna living in the recently burned areas. Small mammals respond rapidly to changes in habitat structure and composition after fire, but the effects of fire can be ameliorated by some management strategies (e.g., salvage logging). Hence, it is necessary to explore whether alternative management strategies may be able to return the ecosystem to its initial state. We studied the small mammal community by live trapping on eight plots under different post-fire treatments in Sant Llorenç del Munt i l’Obac Natural Park (Barcelona province, NE Spain). At the community level, an increase in overall relative abundance and species density was observed in the burned areas. Apodemus sylvaticus, the most abundant mammal in study area, used woody debris piles as a shelter against predators. Mus spretus was more abundant in post-fire sites with large open areas interspersed with woody debris piles. Crocidura russula steadily increased its presence in later successional stages when ground cover became more complex. Our results suggest that combining different management strategies may be appropriate to improve the habitat suitability and biodiversity of small mammals and other key open-land species throughout the burned area. Full article

Scientific studies are increasing day by day with the development of technology. Today, more than 171 billion academic records are made available to researchers via the Web of Science database, which is frequently followed by the scientific community, and is where records of articles, proceedings, and books in many different fields are kept. More than 40 thousand studies are reached when a search is made for research on forest fires in the relevant database. It is unfeasible to examine and read so many publications and understand what topics are important in the relevant field, what is trending, or whether there is a difference between the subjects studied based on years and/or regions/countries. The most effective and scientific method of deriving information from such large and unstructured data is text mining. In this study, text mining is used to reveal where the research on forest fires in the Web of Science database concentrates, which study topics have emerged, how an issue’s level of importance changes over the years, and which topics different countries focus on. Therefore, the abstracts of approximately 32 thousand articles published in English were collected and analyzed based on the country of the authors and the published years. Over 600 words in the abstracts were indexed for each article and their importance was calculated according to inverse document frequency. A size reduction was made to determine the main concepts of the articles by using the singular value decomposition and a total of 29 different concepts were found. Among these, important concepts can be mentioned such as damage to vegetation and species affected, post-fire actions, fire management, and post-fire structural changes. Considering all the articles, studies on soil, fuel (biofuel), treatment, emissions, and species were found to be important. The results we have obtained in this study are by no means a summary of the research carried out in the field; they do, however, allow statistical due diligence concerning, for example, which subjects are important in the relevant field, the determination of increasing and decreasing trending topics, which countries attach importance to in the same research, and so on. Thus, it will function as be a guide in terms of the direction, timing, and budget allocation of research plans in a specific area in the future. Full article

In terms of researching fire-related structure loss, various factors can affect structure survival during a wildfire. This paper aims to assess which factors were determinants in house resistance in the specific context of a case study of an extreme wildfire in the Central Region of Portugal and therefore which factors should be taken into account in the definition of a municipal mitigation strategy to defend buildings against wildfires. In this context, it is possible to conclude that various factors presented a predominant influence, some in building destruction and others in building survival. The existence of overhanging vegetation and lack of defensible space constitute major factors for structure destruction. the inherent wildfire severity, the location in the forest area, and the structure’s isolation from major roads were equally important factors that induced house destruction. Building survival was determined by its increasing distance from the forest and by its location in a dense urban agglomeration. Thus, a strategy to enhance resilience should include the prohibition of roof overhanging vegetation and the restriction of building permits in forest areas, in isolated locations, and/or very far from major roads. These orientations can be extrapolated to municipalities with similar susceptibility and vulnerability to wildfires. Full article

Fire departments’ performance assessment (FDPA) is an important task for fire protection service (FPS) authorities to evaluate fire departments’ (FDs) efficiencies, identify the efficient FDs, and identify areas for improvement of the inefficient units. Therefore, many countries all around the world conducted FDPA research and published its results. Although Portugal is a country with many old cities and buildings, to the best of our knowledge, no FDPA study has been conducted. Hence, the objective of this paper is to conduct a FDPA on Portuguese (PT) FDs using the general FDPA framework and slack-based data envelopment analysis. The results of analyzing the 376 PT-FDs’ data in 2020 showed that only 22 out of 376 FDs were efficient; in addition, in most districts in Portugal, less than 10% of FDs were efficient, and a high percentage of FDs had less than 50% efficiency. Further details and findings are discussed, and some recommendations are provided throughout the paper. The paper’s findings could help the FPS decision maker have a better view of the FDs’ performances and take corrective actions to improve efficiencies. It can also help the FDPA evaluator to have a better understanding of how a FDPA can be conducted and discussed. Full article

The traditional route to achieving adequate structural performance in the event of fire is through ensuring that structural elements attain fire resistance ratings. The magnitude of these ratings typically varies in function of the building use, size, and height. In their genesis, fire resistance ratings were a proxy for the specification required of elements such that they had a reasonable likelihood of surviving the full duration of a fire, i.e., burn-out. As such, fire resistance periods were specified in the function of fire load, which, over time, progressively increased in consideration of the consequences of fire induced structural failure. This ratcheting of fire resistance periods was seemingly done so based on the collective experience of the profession, in response to observations from real fires and, where applicable, resulting disasters. That is, the safety levels associated with current fire resistance recommendations in most global codes and guidance documents are not determined. Therefore, this paper presents a review of reliability-based acceptance criteria for structures, ahead of their application, to determine fire resistance recommendations for buildings in England based on both codified reliability indices and the principle of relative (marginal) lifesaving costs. The study applies a novel form of probabilistic time equivalence, which is augmented by fire occurrence related statistics/parameters, to arrive at risk-informed fire resistance ratings that directly relate to the life safety consequences of fire induced structural failure (i.e., fatalities) to adequate fire resistance ratings. In determining these building fire resistance periods, it is observed that safety targets which implicitly include material damage and building reconstruction costs result in fire resistance recommendations that are well-aligned with National codes and standards. That is, to some extent, the ratcheting of fire resistance periods with time has resulted in some potential resilience to fire. Where safety targets are rationalised in consideration of life safety only, i.e., through the principle of relative (marginal) lifesaving costs, it is shown that fire resistance periods can be optimised, particularly in sprinkler protected buildings. However, this has the potential to introduce vulnerabilities to common mode failures. Full article

Hydrogen fuel cell vehicle (HFCV) technology poses great promise as an alternative to significantly reduce the environmental impact of the transport sector’s emissions. However, hydrogen fuel cell technology is relatively new, therefore, confirmation of the reliability and safety analysis is still required, particularly for fire scenarios within confined spaces such as tunnels. This study applied the computational fluid dynamics (CFD) simulations in conjunction with probabilistic calculation methods to determine the associated thermal risk of a hydrogen jet fire in a tunnel and its dependency on scenarios with different tunnel slopes, longitudinal and transverse ventilation velocities, and fire positions. A large-scale model of 102 m in which the effects of outlined parameter variations on the severity of the fire incident were analysed. It is found that both tunnel ventilation techniques and slope were critical for the effective ejection of accumulated heat. With ventilation playing a primary role in the ejection of heat and gas and slope ensuring the stability of the ejected heat, probabilities of thermal burns were found to be reduced by up to approximately 35% with a strong suggestion of critical combinations to further reduce the dangers of hydrogen tunnel fires. Full article

Managing protected areas requires knowing what factors control fire ignitions and how likely they are compared to non-protected ones. Here, we modelled fire ignition likelihood in west-central Spain as a function of biophysical and anthropogenic variables in 172 protected areas (PA) of the Natura 2000 network, their buffer zones (BZ, 1500 m area surrounding PA), and non-protected areas (NP). Ignition coordinates from fire statistics (2001–2015 period) were overlaid over maps of relevant biophysical and socioeconomic variables. Models were built for four different fire sizes, small (1–5 ha), medium (5–50 ha), large (50–500 ha), and very large (≥500 ha), using Maxent software. Additionally, PA were classified based on their land use and land cover types by cluster analysis. Mean ignition probabilities were compared between PA, BZ and NP, as well as among different types of PA, by generalized linear models. Maxent models’ accuracy increased as fires were of larger size. Ignitions of small fires were associated with anthropogenic variables, while those of larger fires were more associated with biophysical ones. Ignition likelihood for the small and medium fire sizes was highest in BZ, while being the lowest in PA. Conversely, the likelihood of large and, particularly, very large fires was highest in PA. Mean ignition likelihood varied among types of PA, being highest for very large fires in PA, dominated by pine and mixed forests. Our results support the hypothesis that PAs are at the highest risk of large fire ignition, but BZ were also at high risk for the rest of the fire sizes. This largely reflects the more hazardous nature of PA landscapes. This work provides the needed tools to identify critical fire ignition areas within and nearby protected areas, which should be considered in their conservation and management plans. Full article

Heat input and ash residues are main components of vegetation fire disturbances. Understanding the distinct impacts of heat and ash on soil microorganisms is crucial to comprehend and predict the induced changes in soil ecosystem composition and dynamics following different types of fire disturbances. This study’s main goal was to track the dynamic shifts in the community of soil nematode-trapping fungi (NTF) following the separate disturbances of heat and ash by means of a specifically designed experiment conducted in the field. Four simulated fire treatments, one treatment reproducing natural burning, and one control treatment were taken into account. Every ten days following the disturbance, soil samples from each treatment were collected, and soil NTF and physicochemical characteristics were measured. The results showed that: (1) Heat drastically decreased the number of strains and heavily altered the NTF community, but it also encouraged the emergence of new NTF species. Instead, no overt changes were observed in the treatment that just experienced the addition of ash on the soil. (2) When compared to treatments that received only heat input, the lower strain count of NTF recovered more quickly in the natural burning treatment which was affected by both heat and ash input. These findings suggest that the disruptive effect of fire heat on soil NTF biomass may be counterbalanced by the emergence of new species and the repairing capabilities of new nutrients introduced by ash residue. In the future, both conventional and cutting-edge techniques should be considered in research designs to better understand the ecological role of fire disturbances occurring at different intensities, as well as the mechanisms that make soil ecosystems resilient to fire, in particular the role of new species. Full article

Fire strongly impacts the composition and structure of ecosystems, with consequences yet to be understood. We used Moderate Resolution Imaging Spectroradiometer (MODIS) data to map fire frequency and fire intensity and investigate their effects on miombo woodlands (MW) of central Mozambique. Tree species diversity was evaluated and compared using rarefaction curves. Non-metric multidimensional scaling (NMDS) ordination was used to identify patterns of species composition occurrence. The indicator value index method was applied to verify the occurrence of fire indicator species. In general, tree communities responded differently to varied fire regimes. We found low tree density in Intermediate fire frequency and intensity (IfIi) (180 trees ha⁻¹) and High-frequency and Low intensity (HfLi) (316 trees ha⁻¹) areas. The IfIi fire regime had the lowest carbon stocks (9.1 Mg ha⁻¹), when compared to the rest of fire regimes. The species diversity decreased as fire intensity increased. IfIi areas had the maximum species diversity. The NMDS showed a varied species composition according to fire regime. We found a strong relationship between the species diversity and composition, and the pattern of fire occurrence in each fire regime. Our results are critical in supporting fire management policies and understanding fire regimes and their effects on miombo trees’ structure and composition. Full article

Fires will become an increasingly frequent perturbation even under the conditions of the mild climate zone and will interfere with the agricultural landscape. Fire is a natural phenomenon, and depending on ecosystems, vegetation may develop and contribute to the occurrence and spread of fire. Vegetation of the sour cherry orchard located in the climatically dry conditions of the South Moravian Region, Czech Republic (CR), was evaluated. Vegetation assessment was performed using phytocenological relevé. In each variant, 10 relevé were recorded. Coverage of the found species was estimated directly in percentages. Moreover, the maximum height in the stand was measured for each type of plant. Biomass of individual plant species was calculated, using the biomass index (IB) equation. The IB values of individual plant species in the treatments were processed by employing a multidimensional analysis of the ecological data. Different vegetation management practices in an orchard change the species diversity of the vegetation and thus the fire hazards in the orchard conditions. Grassy interrow has the most grass biomass during the entire vegetation season, and therefore represents the greatest hazard and spread of fire. The most important grasses include Arrhenatherum elatius, Dactylis glomerata, Festuca pratensis, Lolium perenne, and Poa pratensis. On the contrary, bare soil conditions in the interrow are most suitable for annual species, and this is the place with the highest changes in the number of species during the growing season. Biomass of the orchard vegetation combined with dry and warm weather increases the fire hazard. Annual and perennial grasses have very good potential for the production of biomass, which increases the hazard of fire. The nature of the vegetation in the orchards has the potential for the actual start of a fire and its subsequent spread, however, under other environmental conditions. During hot and dry weather, dead biomass may accumulate resulting in increasing the hazard of large wildfires. Varied orchard management practices lead to a higher diversity of vegetation and make orchards, islands of biodiversity in the agricultural landscape. Full article

Understanding the conditions when litter beds will ignite from firebrands is critical for predicting spot fire occurrence. Such research is either field- or laboratory-based, with limited analysis to compare the approaches. We examined the ability of a laboratory method to represent field-scale ignitability. The laboratory method involved collecting litter-bed samples concurrently with the field experiments and then reconstructing and burning the litter-bed samples in the laboratory. We measured the number of successful and sustained ignitions in the laboratory (n = 5) and field (n = 30 attempts). The laboratory and field results were more similar for successful (bias = 0.05) than sustained ignitions (bias = 0.08). Wind, fuel structure (in the field) and near-surface fuel moisture influenced the differences between the methods. Our study highlights the value in conducting simultaneous laboratory and field experiments to understand the scalability of laboratory studies. For our ignitability method, our results suggest that small-scale laboratory experiments could be an effective substitute for field experiments in forests where litter beds are the dominant fuel layer and where the cover of the near-surface fuel is low. Full article

Although it is hard to predict wildfires, risky areas can be systematically assessed and managed. Some of the factors for decision-making are hazard, vulnerability, and risk maps, which are the end product of wildfire mapping. This study deals with wildfire risk analysis in Queensland, Australia. A review of the previous studies focusing on each aspect has been done and used with wildfire records from 2011 to 2019 in Queensland, Australia, to compile the required input models to detect risky wildfire regions. Machine learning (ML) methods of Decision Tree (DT) and Support Vector Machine (SVM) were used to perform hazard assessment. The reason was to select the most accurate outcomes for the rest of the analysis. Among accuracy assessment techniques, the Area Under Curvature (AUC) method was used to evaluate the hazard maps. Prediction rates of 89.21% and 83.78% were obtained for DT and SVM, respectively. The DT prediction value showed that the DT-hazard map was more accurate than the SVM-hazard map. Vulnerability analysis was implemented by assigning weights to each factor according to the literature. Lastly, in order to create the wildfire risk map, the hazard and vulnerability indices were combined. The risk map showed that particularly dense urbanization regions are under future wildfire risk. To perform preliminary land use planning, this output can be used by local governmental authorities. Full article

The aim of the present work is to account for polydisperse effects in a two-phase flow with a simple and fast method. Polydisperse two-phase flows arise in numerous applications. Fire sprinkler systems are relevant examples as they release clouds of polydisperse droplets. Another relevant example is the polydisperse two-phase flow created by the detonation of an explosive charge surrounded by a liquid layer. In such a situation, material interfaces are initially present and the created two-phase flow consists of a carrier gas phase and a liquid phase involving many droplets of various sizes. Spherical particles or droplets are usually assumed in two-phase flow computations. When dealing with explosion situations involving both dense and dilute flow regimes, multiple particle diameters can be addressed but at the price of introducing as many additional equations that describe mass, momentum and energy balance of the various particle classes. Consequently, the computation time needed to address numerical resolution increases tremendously. Under explosion situations involving many particle diameters, the method becomes intractable and is usually reduced to a single diameter, which is often insufficient. A simplified approach is developed in the present work to account for a substantial number of particles of different sizes with few extra computational cost. The approach is said to be simplified as a single velocity and a single temperature are considered for all the spherical particles, regardless of their diameters. This type of modeling seems apt for the target explosion situations. The focus is placed on the interfacial area, which is the main parameter involved in the coupling of the two phases. In the present work, Gamma-like continuous probability distributions are considered to address the various sizes of particles. The effects of the size distribution are only summarized in the specific interfacial area, yielding consequently few code modifications while taking into account the polydisperse aspect of the two-phase flow. Full article

Firebrands are the primary source of ignition for large wildfires and urban wildfires (WUIs). China is a country with a high incidence of forest fires, and there are great differences in the terrain, climate, and other natural conditions in different regions; the frequency of forest fire will lead to greater regional differences. In the process of fighting forest fire, the fire commander should make an accurate analysis and judgment according to the various signs of the fire, which are the key to ensure the safety of the participants and to realize a quick decision. Existing studies of firebrands formation have been performed using limited quantities of wildland fuels with limited MC fuel levels and environmental conditions and lacking comprehensive data analysis including typical wildland timbers basic fuel, pyrolysis and flammability properties, and forest fire dynamic knowledge (including forest fire development period analysis and the harm of heat flux to the human body) to guide the firefighting strategy. To better understand the characteristics of firebrand formation in different Chinese regional places, a systematic study to quantify wildland fuels ignition formation by testing different fuels under different conditions is needed. The objective of this study was to determine the basic pyrolysis and flammability of wildland fuels with high fire intensity in typical areas of China to provide relevant property data, offering insight into how wildland fuels arrangement can determine the movement of wildfires for firefighting strategy. Thermogravimetric analysis (TGA) was used to determine the pyrolysis performance of selected wild fuels under different heating rates and different fuel MC values. The flammability of selected wildland fuels at different heat fluxes and at different moisture contents was determined using a cone calorimeter. This study measured the pyrolysis and flammability of some selected wildland fuels and found that some controlling factors (MC levels, heating conditions) influenced the outcome variables, especially the flammability of wildland timber. Fire behavior refers to the intensity at which a fire burns and how it moves. This research results point out the following: (1) Forest fire barriers or fuel breaks should be separated among Eucalyptus robusta Smith and Pinus massoniana before or in the fire due to high risk for ignition and strong flammability, and it is suggested to remove, control, and replace high-risk flammable timbers with low-risk flammable timbers as a part of long-term wildland fire management strategies. (2) Fire commanders could utilize some research to test conclusions and make an accurate analysis and judgment: The TTI time for each material indicates the ideal time for firefighters to put out fire, the peak of heat-release time indicates a fully developed fire to suggest firefighters finish work before the forest fire spirals out of control, and the flameout time represents the moment of low risk of fuel ignition, so firefighters could allow the fuel to burn out and change the extinguishing target to other regions of developing forest firebrands. Full article

Understanding the ecological role of fire in forests is essential for proper management and conservation programs. The objectives of this study were: (1) to reconstruct the history of fires in a temperate forest in Sierra Madre Occidental; and (2) to interpret the impacts of fire and climate on forest structure. Sixty tree cross-sections with fire scars were analyzed, and descriptive statistics of fire history were generated. Additionally, growth cores were analyzed, and the ages of trees of different diameter categories were calculated. The synchrony between fire history and tree establishment was determined, and precipitation and Palmer Drought Severity Index (PDSI) values were correlated with the number of trees established per year. The presence of 137 fire scars was determined, which allowed the reconstruction of 41 fire events over the period 1855–2019; however, only the period 1940–2015 was used to compare tree recruitment, as tree establishment was detected in this period. The mean fire interval (MFI) was 2.28 years in general, and 12.17 years for extensive fires. As regards vegetation, a continuous recruitment pattern was observed, typical of a frequent low-intensity fire regime, although peak regeneration occurred after extensive fires. The correlation analysis showed that the number of trees established per year was influenced by the wet conditions that occurred in December of the previous year and the dry conditions in September and October of the previous year. This finding demonstrates the historical influence of fire and climate on the structure of the current stand in the study area. Therefore, the present study highlights the importance of including fire in forest management programs, considering the natural fire regime to which the species in this ecosystem are already adapted. Full article

In the last 21 years, Bolivia has recorded a series of thousands of wildfires that impacted an area of 24 million hectares, mainly in the departments of Beni and Santa Cruz. In this sense, identifying trends in the increase of natural vegetation after wildfires is a fundamental step in implementing strategies and public policies to ensure ecosystem recovery. The main objective of this study was to evaluate the spatial trends of the increase and decrease in vegetation affected by wildfires for the whole of Bolivia, for the period 2001–2021, using non-parametric tests, through the analysis of Normalized Difference Vegetation Index (NDVI) remote sensing products. The results indicated that 53.6% of the area showed an increasing trend (p < 0.05) and 15.9% of the area showed a decreasing trend (p < 0.05). In terms of land cover type, forests were proportionally represented by 18.1% of the areas that showed an increasing trend (p < 0.05) and 3.0% of the forests showed a decreasing trend (p < 0.05). In contrast, non-forested areas showed an increasing trend of 35.5% and 12.9% showed a decreasing trend (p < 0.05). It can be concluded that there is a continuous regeneration process throughout the country. Full article

In order to study the mechanical and damage behavior of concrete shield tunnel segments under a high temperature, two self-compacting concrete and three mixed-fiber (steel and polypropylene fiber) self-compacting concrete test blocks were designed. The influence of several key factors, including fire duration, pre-loading, and concrete type, on the fire behavior of concrete shield tunnel segments were studied. The results show that the type of fiber and pre-loading have an important influence on crack development in concrete shield tunnel segments. Compared with undoped segments, cracks in segments with steel fibers and polypropylene fibers appeared later, and the average crack spacing decreased. The pre-loading has an important effect on the vertical deformation before and after the temperature rise. As the load level increases, so does the deformation after the temperature rise. The influence of the initial load level should be considered when designing the fire resistance of the segment. Full article

The smoke layer height in the ship engine room under forced ventilation has been experimental and theoretical investigated in this work. A series of test were carried out in a scaled engine cabin experimental platform to obtain the influence of air supply volume and air inlet height on the burning parameters, including the mass loss rate, smoke temperature, etc. The research results show that under the experimental conditions, the fire source mass loss rate increases exponentially, and smoke layer height also increases gradually with the increase in the air supply volume. The empirical formula of smoke layer height under different air supply conditions was given. Then, a prediction model of smoke layer height under different forced ventilation conditions was constructed through theoretical analysis based on conservation equations. Within the range of experimental air volume and air inlet height, the relative error between theoretical prediction results and experimental results was less than 11%, which could effectively predict the smoke layer height in the ship cabin fire. Full article

In instrumented prescribed fires, the ignition procedure requires much attention. In this paper, we investigate the effects of two ignition procedures on the fire head using a 3D numerical model. The first procedure is to ignite the fire from the edges of the fire line towards the centre of the line. The second procedure consists of igniting the fire from the centre of the fire line to the edges of the line. The 3D numerical model used is based on the modelling of the fuel layer from Lagrangian particles, and the fire propagation is based on a two-phase model. The model was tested on an experimental fire in a wheat field in southern Australia. The model predicted the experimental fire front well. Analysis of the impact of the ignition procedure on the fire head showed that the quasi-steady-state rate of fire spread was the same for both procedures. However, before the quasi-stationary state, the front of the first procedure spread faster than that of the second procedure. The fire front in the first procedure was wider than in the second procedure. It was also found that the length of the head fire in the first procedure remained the same as that of the ignition line. In the second procedure, the length of the head fire was one-third of that of the ignition line. Full article

It remains a challenge to prepare flame-retardant composites via the addition of a low content of flame retardant. In this work, a novel DOPO-functionalized reduced graphene oxide hybrid (DOPO-M-rGO) flame-retardant system was synthesized for epoxy resin (EP). The phosphorus-nitrogen-reduced graphene oxide ternary synergistic effect provided DOPO-M-rGO with high flame-resistance efficiency in EP; thus, the EP-based composite exhibited superior fire-resistant performance at extremely low DOPO-M-rGO loading. The limiting oxygen index (LOI) of the EP-based composite was increased from 25% to 32% with only 1.5 wt% DOPO-M-rGO addition, and the peak heat release rate (pHRR), total heat release (THR), and total smoke production (TSP) were significantly decreased by 55%, 30%, and 20%, respectively. In addition, as a halogen-free flame-retardant system, DOPO-M-rGO presents great application potential as an eco-friendly additive for the flame-resistance improvement of thermosetting polymer materials. Full article

Utilizing ultrasonic excitation as an active method for studying the rate of heat transfer has gained considerable attention recently. The present study investigated the effects of ultrasonic excitation on the heat transfer rate in a fin-and-flat tube heat exchanger experimentally. The performance of the heat exchanger was investigated with and without the presence of ultrasonic excitation. A comprehensive parameter study was attempted, so several parameters, including ambient temperature, flow rate, air passing velocity, Reynolds number, and Nusselt number, were studied in a relatively wide range. An adequate uncertainty test, as well as a validation assessment, is provided to certify the credibility of the obtained results and the hired facility. The results revealed that reducing the flow rate, ambient temperature, and air passing velocity on the heat exchanger increased the ultrasonic excitation’s effects. The highest heat transfer enhancement in the present experiment was 70.11%, measured at the lowest air passing velocity and ambient temperature with a Reynolds number 2166. The data presented in this paper will be useful for the optimal design of ultrasonic vibrating fin-and-tube heat exchangers. Full article

Wildfires are complex phenomena, both in time and space, in ecosystems. The ability to understand wildfire dynamics and to predict the behaviour of the propagating fire is essential and at the same time a challenging practice. A common approach to investigate and predict such phenomena is making the most of power of numerical models and simulators. Improved and more accurate methods for simulating fire dynamics are indispensable to managing suppression plans and controlled burns, decreasing the fuel load and having a better assessment of wildfire risk mitigation methodologies. This paper is focused on the investigation of existing simulator models applicable in predicting wildfire spread and wind fire interaction. The available software packages are outlined with their broad range of applications in fire dynamic modeling. Significance of each work and associated shortcomings are critically reviewed. Finally, advanced simulations and designs, accurate assumptions, and considerations for improving the numerical simulations, existing knowledge gaps in scientific research and suggestions to achieve more efficient developments in this area are revisited. Full article

This research establishes a “detect-decide-action” agent-based evacuation model based on the social force model, introducing an active steering force into the basis of the dynamic equation with the combination of the behavioral decision model and the probability model. In the AEM, the detection algorithm is used to identify pedestrians or obstacles within the detection radius to provide the next walking direction and apply the active steering force. The obstacle avoidance algorithm is the core of the “action” link. This research focuses on the establishment of the following and bypassing algorithm when moving in the same direction, and the algorithm of a detour when moving in the opposite direction, applying C++ programming language to achieve the basic evacuation behavior simulation of avoiding pedestrians and obstacles in the actual scene. The results show that compared with the grid model and the general social force model, the agent model (AEM) solves the problem of the distortion of evacuation behavior to some extent, and the pedestrian is more flexible in the choice of evacuation path. Full article

More cautious fire safety evacuation assessment and escape route assistance are required when people with disabilities encounter a fire hazard in a historical museum. This study uses the old Chiayi City Hall, which is mainly used for an exhibition space, as the example. The core of this study is the problem of fire evacuation that emerged after the historic building opened and was reused as a museum; it uses Pathfinder evacuation simulation software, discussing the difference between traditional and segregated evacuation and assuming the original evacuation, elevator emergency evacuation, and external ramp evaluation. There are three evacuation scenarios, and the number of accommodated people is set to 730, pursuant to the applicable law. Comparing the conditions of people with disabilities and ordinary members of the public during evacuation through the foregoing three scenarios, the overall evacuation time and survival rate of the original evacuation scenario are 440 s and 49.8%, respectively; and the overall evacuation time and survival rate of the barrier-free elevator emergency evacuation scenario are 332 s and 65.4%, respectively; the overall evacuation time and survival rate of the external ramp evaluation scenario are 320 s and 65.6%, respectively. The computer data analysis shows that the use of the external ramp evaluation gives people with disabilities the best evacuation time and survival rate because the architectural form of cultural heritage buildings is more fragile, specific, and fast-burning than that of ordinary buildings. As the global awareness of cultural asset preservation and revitalization is increasing, the evacuation of people with disabilities in the building in the case of fire is very important. The results of this study can be used as an emergency evacuation design recommendation for people with disabilities in the cultural assets through evacuation simulation analysis. Full article

Forestry woodchip and spent mushroom compost have commercial potential as sustainable residues in biological and chemical processes for energy production. This study focuses on the evaluation of agri-food industry waste energy valorization, with the aim to reduce the valuable biomass utilization for energy production without decreasing the process quality, thereby pursuing economic and environmental advantages. Burning trials were conducted in a fluidized bed biomass plant provided with emission abatement systems. The biomass mixture used for combustion was composed of pine and oak woodchip and spent mushroom compost. The biomass used was first characterized through compositional and energetic analysis, and subsequently, during the burning tests, a monitoring sampling campaign was carried out to analyze the gas and particles emission. Optimal combustion conditions were observed during combustion, with good oxidation of the organic material, relatively high CO₂ production, and low CO concentration in flue gas. Nevertheless, SO₂ concentrations in the combustion flue gas are greater than those found in the combustion of the most commonly used biomasses. In fact, the mixture compositional characterization revealed a non-negligible concentration of sulfur, which explains the high values of SO₂ detected in emission. The obtained results confirm that controlled combustion, together with suitable biomasses utilization, preliminary characterization, and emission monitoring, are essential practices for the realization of a sustainable process, both from an energy and environmental point of view. Full article

While the Mediterranean basin is foreseen to be highly affected by climate change (CC) and severe forest fires are expected to be more frequent, international efforts to fight against CC do not consider forest fires’ greenhouse gas (GHG) emissions risk and the possibility of its mitigation. This is partly due to a lack of a methodology for GHG risk spatial assessment and consideration of the high value of carbon stocks in forest ecosystems and their intrinsic risk. To revert this, an innovative GHG emission risk model has been developed and implemented in a pilot forest area. This model considers geospatial variables to build up emission vulnerability based on potential fire severity and resistance of a landscape, value at risk and the hazard of a fire occurrence. The results classify low, moderate and high emission risks in the analysed areas. This identification of hotspots allows the prioritisation of fire prevention measures in a region to maximise the reduction of GHG emissions in the case of a fire event. This constitutes the first step in a holistic and consistent CC mitigation that not only considers anthropic GHG sources but also possible GHG emissions by forest fires that can be actively prevented, managed and reduced. Full article

The coal-seam fire is one of the most significant disasters in the coal mining industry in China, affecting the safety of coal production in China. The working-position risk in coal mining has an important impact on the risk of fire occurrence, and thus it would be worthwhile to analyze working-position risks so as to effectively prevent and control coal-seam fires. Based on the kernel density estimation (KDE), this research puts forward an innovative calculation-model and assessment method of the superposition risk of the working position on coal-seam fire accidents. This research aims to evaluate the priority of risk management of working positions in coal-seam fire accidents. In order to achieve this research aim and objectives, this research carried out a statistical analysis of 100 classic cases of coal-seam fire accidents from 2000 to 2022, using the accident-tree-structure importance analysis method. This research contributed to the evaluation of the frequency and severity of various risk factors leading to fire accidents, and the development of the value at risk (VaR) of various risk factors in the coal-seam fire accidents. Integrating all the risk factors involved in each position and their risk values, and building a position-risk calculation model was carried out. In addition, in accordance with the kernel density estimation (KDE), a post-superposition risk model was established. Moreover, ArcGIS software was used to obtain the superimposed risk of posts and build a risk-distribution map. Based on the possibility of post-risk occurrence and the severity of the consequences, a risk-assessment matrix was developed, a post-risk grading standard was established, and risk levels of the working position were divided up in this research. Results indicated that (1) before risk superposition, working-position risks and risk levels are densely distributed, and nearly 80% of risk levels of the working position are focused on Level II and III, without Level I. (2) After risk superposition, the post-risk is affected by the surrounding post-risk, and the risk- and level-distribution is more hierarchical; the number of Level I risks in working positions increased to 12, which were mainly distributed among the comprehensive mining team, comprehensive excavation team and ventilation team, which accords more with the objective and actual production-conditions. The risk-distribution map directly showed that the post-fire risk at the mining face and shaft is higher, a result which will take on a significant guiding role in the effective control and prevention of risk in coal-seam fires in the future. Full article

Response time is an important factor in fire operations. A continuous assessment of response time is crucial in order to monitor firefighters’ performance level. An initial assessment of fire response time was conducted for fire stations in categories A-D throughout Malaysia from 2018 to 2020. The categories were determined based on risk profiling scores. In this study, the mean response time and distance travelled for the selected fire stations were calculated. To measure the fire station’s performance, a 10 min standard response time was used as a benchmark. One-way analysis of variance (ANOVA) was also applied to statistically determine any significant differences between mean response time and mean distance travelled. Among the four categories, category C and D fire stations recorded high values for mean distance travelled and mean response time. Category C fire stations recorded the mean response time, at 15.1 min, and distance travelled, 20.1 km. The areas where category D fire stations are located have low population density, resulting in greater coverage for the stations. Most of the fire stations in this category had approximately 13.8 km travel distance with a mean response time of 17.9 min. Category C and D fire stations require a substantial amount of time to reach incident locations due to the low-quality road network and the local topography. A new profiling method for minimizing fire risk based on constant development in these areas might be necessary for future improvement. Additionally, new category C and D fire stations would meet the demands of expanding communities. It is important to note that establishing a demand zone in Malaysia with specific response time could give a better indication of firefighters’ performance in the future. Full article