Fire

The analysis conducted herein has shown that the efficiency of smoke precipitation can be improved by additionally making smoke particles interact with ultrasonic (US) oscillations. Because the efficiency of US coagulation lowers when small particles assemble into agglomerates, the authors of this work have suggested studying how smoke particles interact with complex sound fields. The fields are formed by at least two US transducers which work at a similar frequency or on frequencies with small deviations. To form these fields, high-efficiency bending wave ultrasonic transducers have been developed and suggested. It has been shown that a complex ultrasonic field significantly enhances smoke precipitation. The field in question was constructed by simultaneously emitting 22 kHz US oscillations with a sound pressure level no lower than 140 dB at a distance of 1 m. The difference in US oscillations’ frequencies was no more than 300 Hz. Due to the effect of multi-frequency ultrasonic oscillations induced in the experimental smoke chamber, it was possible to provide a transmissivity value of 0.8 at a distance of 1 m from the transducers and 0.9 at a distance of 2 m. Thus, the uniform visibility improvement and complete suppression of incoming smoke was achieved. At the same time, the dual-frequency effect does not require an increase in ultrasonic energy for smoke due to the agglomeration of small particles under the influence of high-frequency ultrasonic vibrations and the further aggregation of the formed agglomerates by creating conditions for the additional rotational movement of the agglomerates due to low-frequency vibrations. Full article

In coal mines, the mixture of coal dust and gas is more ignitable than gas alone, posing a high explosion risk to workers. Using the explosion tube, this study examines the explosion propagation characteristics and flame temperature of low-concentration gas and coal dust mixtures with various particle sizes. The CPD model and Chemkin-Pro 19.2 simulate the reaction kinetics of these explosions. Findings show that when the gas concentration is below its explosive limit, coal dust addition lowers the gas’s explosive threshold, potentially causing an explosion. Coal particle size significantly affects explosion propagation dynamics, with smaller particles producing faster flame velocities and higher temperatures. Due to their larger surface area, smaller particles absorb heat faster and undergo thermal decomposition, releasing combustible gases that intensify the explosion flame. The predicted yield of light gases from both coal types exceeds 40 wt% daf, raising combustible gas concentrations in the system. When accumulated reaction heat elevates the gas concentration to its explosive limit, an explosion occurs. These results are crucial for preventing gas and coal dust explosion accidents in coal mines. Full article

Wildfires and post-fire restoration methods significantly impact soil physicochemical properties and microbial characteristics in forest ecosystems. Understanding post-fire soil recovery and the impacts of various post-fire restoration methods is essential for developing effective restoration strategies. This study aimed to investigate how fire and soil depth influence soil physicochemical properties, enzymatic activities, and the structure of microbial communities, as well as how these factors change under different post-fire management practices. We sampled 0–10 cm (topsoil) and 10–20 cm (subsoil) in unburned plots, naturally restored plots, and two afforestation plots in southern China. The results showed that fire reduced topsoil soil moisture, nutrient levels, and microbial biomass. The variations in soil physicochemical properties significantly influenced microbial processes. Soil bulk density, nitrate, ammonium, carbon-to-nitrogen ratio, and availability of nitrogen, phosphorus, and potassium availability influenced soil enzyme activities. Soil pH, ammonium nitrogen, and the availability of nitrogen, phosphorus, and potassium were key factors shaping microbial composition. Fire altered the soil microbial communities by reducing the availability of nitrogen. Soil depth alleviated the impact of fire on the soil to some degree. Although artificial interventions reduced soil organic carbon, total nitrogen, and phosphorus, planting nitrogen-fixing species, such as Acacia mangium, promoted microbial recovery. Full article

The 2019–2020 Black Summer bushfire in Australia is a good example of the frequent and severe bushfires (wildfires) observed around the world in recent years. Fire-enhanced winds and fire–wind interactions during those bushfire events have caused increased wind velocities in the vicinity of a bushfire front. This can lead to a premature failure of the building envelope, making it vulnerable to ember attack and direct flame contact. In Australia, crest-fixed cold-formed steel (CFS) claddings are commonly used for buildings in bushfire-prone areas because of their non-combustibility. Therefore, this study investigated the pull-through failure behaviour of corrugated CFS claddings under wind uplift/suction loading at elevated temperatures, simulating fire-enhanced winds during a bushfire by means of experimental and numerical studies. Experimental results showed a negligible influence of the thermal expansion of the cladding system on the pull-through failure behaviour, while a significant decrease in pull-through capacity was observed with increasing temperatures. Suitable finite element models were developed, validated and used in a detailed numerical parametric study. Based on the findings from these studies, a design equation was proposed for the pull-through capacity of the crest-fixed corrugated claddings at elevated temperatures. Full article

Chyulu Hills, Kenya, serves as one of the region’s water towers by supplying groundwater to surrounding streams and springs in southern Kenya. In a semiarid region, this water is crucial to the survival of local people, farms, and wildlife. The Chyulu Hills is also very prone to fires, and large areas of the range burn each year during the dry season. Currently, there are no detailed fire records or burn scar maps to track the burn history. Mapping burn scars using remote sensing is a cost-effective approach to monitor fire activity over time. However, it is not clear whether spectral burn indices developed elsewhere can be directly applied here when Chyulu Hills contains mostly grassland and bushland vegetation. Additionally, burn scars are usually no longer detectable after an intervening rainy season. In this study, we calculated the Differenced Normalized Burn Ratio (dNBR) and two versions of the Relative Differenced Normalized Burn Ratio (RdNBR) using Landsat Operational Land Imager (OLI) and Sentinel-2 MultiSpectral Instrument (MSI) data to determine which index, threshold values, instrument, and Sentinel near-infrared (NIR) band work best to map burn scars in Chyulu Hills, Kenya. The results indicate that the Relative Differenced Normalized Burn Ratio from Landsat OLI had the highest accuracy for mapping burn scars while also minimizing false positives (commission error). While mapping burn scars, it became clear that adjusting the threshold value for an index resulted in tradeoffs between false positives and false negatives. While none were perfect, this is an important consideration going forward. Given the length of the Landsat archive, there is potential to expand this work to additional years. Full article

Domestic electrical fires can occur for a variety of reasons, including faulty wiring and plugs, overloaded circuits, and malfunctioning electrical appliances. In this article, the circumstances of domestic electrical fire injuries between 2011 and 2022 in the county of Merseyside in Northwestern England were examined in order to inform fire prevention activities. Householder carelessness appeared to be less of a factor in electrical fire injury compared to other types of fire injury such as cooking or smoking fire injury. Faulty electricity supplies were the main cause of electrical fire injuries. Male residents were slightly more likely to sustain injury in an electrical fire in comparison to females (1.25 to 1). Those aged 75+ appeared to be more at risk of electrical fire injuries compared to other age groups. Full article

Wildfire risk increases following non-fire disturbance events, but this relationship is not always linear or cumulative, and previous studies are not consistent in differentiating between disturbance loops versus cascades. Previous research on disturbance interactions and their influence on forest fires has primarily focused on fire-prone regions, such as North America, Australia, and Southern Europe. In contrast, less is known about these dynamics in Central Europe, where wildfire risk and hazard are increasing. In recent years, forest disturbances, particularly windthrow, insect outbreaks, and drought, have become more frequent in Central Europe. At the same time, climate change is influencing fire weather conditions that further intensify forest fire dynamics. Here, we synthesize findings from the recent literature on disturbance interactions in Central Europe with the aim to identify disturbance-driven processes that influence the regional fire regime. We propose a conceptual framework of interacting disturbances that can be used in wildfire risk assessments and beyond. In addition, we identify knowledge gaps and make suggestions for future research regarding disturbance interactions and their implications for wildfire activity. Our findings indicate that fire risk in the temperate forests of Central Europe is increasing and that non-fire disturbances and their interactions modify fuel properties that subsequently influence wildfire dynamics in multiple ways. Full article

Wildfires have become a significant environmental and public health concern worldwide, particularly due to their increased frequency and intensity driven by climate change. Wildfire smoke, composed of a complex mixture of particulate matter, gases and chemicals, has been linked to numerous health issues, primarily affecting the respiratory and cardiovascular systems. However, emerging evidence suggests that wildfire smoke exposure also has profound effects on the immune system. This review aims to synthesize current knowledge on how wildfire smoke exposure affects the human immune system, including acute and chronic impacts, underlying mechanisms and potential long-term consequences. The review discusses the role of inflammation, oxidative stress and immune cell modulation in response to wildfire smoke, highlighting the need for further research to fully understand these effects. Full article

The unique structure of ancient buildings poses a significant risk of fire hazards, so the assessment of potential fire risk is of great significance to fire safety management. This paper examines the fire risk associated with the building complex of the Palace Museum. Firstly, a fire risk assessment indicator system was constructed based on three dimensions: hazard factors, sensitivity of hazard-bearing bodies, and loss control factors. Secondly, the weight values for each index were calculated based on the entropy weight method. Finally, the monthly fire risk assessment levels in the year 2019 were visualized by using a geographic information system. Based on the fire risk assessment results, this study quantitatively reveals the fire risk driving mechanism of ancient buildings in the Palace Museum from the perspective of spatial stratified heterogeneity by using the geodetector model. The results show that there are differences between the main factors that affect the weight of fire risk assessment and the main factors that cause the spatial heterogeneity of fire risk. Factors such as the safety protective grade and staff number contribute to a stronger explanation of the spatial stratified heterogeneity for fire risk within the museum. The results can help us to understand the driving factors affecting the distribution patterns of fire risk for the Palace Museum and could provide support for the formulation of fire prevention and safety management measures. Full article

(1) Background: Forest fires are widespread in Mediterranean-climate regions and are becoming very common in urban and peri-urban areas. (2) Methods: Wildfires in Attica since 1977 are mapped and types of vegetation burned are reported. (3) Results: Fires are becoming larger. During the period of study (1977–2024), 45% of the burned area was covered with Pinus halepensis forests, 1.4% with Abies cephalonica forests, and 18.5% with shrublands. A relatively high percentage of the burned area (BA) affected more than once consisted of pine forests (65%). Ten percent of the total BA lies within the boundaries of the Natura 2000 network, Europe’s most important network of protected areas, of which 38.9% was burned. At the interannual scale, the BA in Attica is negatively correlated with relative humidity, while reduced precipitation may contribute to the expansion of wildfires. (4) Conclusions: Fires are becoming larger over time, with low humidity increasing the higher fire risk. Since the changing climate is expected to create more severe and uncontrollable conditions, mitigation and adaptation measures should be planned and be introduced immediately. Full article

This study analyzes the forest flammability hazard in the south of Tyumen Oblast (Western Siberia, Russia) and identifies variation patterns in fire areas depending on weather and climate characteristics in 2008–2023. Using correlation analysis, we proved that the area of forest fires is primarily affected by maximum temperature, relative air humidity, and the amount of precipitation, as well as by global climate change associated with an increase in carbon dioxide in the atmosphere and the maximum height of snow cover. As a rule, a year before the period of severe forest fires in the south of Tyumen Oblast, the height of snow cover is insignificant, which leads to insufficient soil moisture in the following spring, less or no time for the vegetation to enter the vegetative phase, and the forest leaf floor remaining dry and easily flammable, which contributes to an increase in the fire area. According to the estimates of the CMIP6 project climate models under the SSP2-4.5 scenario, by the end of the 21st century, a gradual increase in the number of summer temperatures above 35 °C is expected, whereas the extreme SSP5-8.5 scenario forecasts the tripling in the number of such hot days. The forecast shows an increase of fire hazardous conditions in the south of Tyumen Oblast by the late 21st century, which should be taken into account in the territory’s economic development. Full article

Many firefighters have inadequate levels of physical fitness which can impair firefighting performance. Understanding the factors that influence exercise and fitness behaviors could help identify those less likely to stay physically fit. Methods: A sample (N = 45) of male recruit firefighters were assessed during weeks 1 and 7 of a state firefighter academy. Measures included cardiovascular fitness, muscular fitness, performance on firefighter ability tasks, exercise intensity preference/tolerance, and extraversion. Results: Exercise intensity preference was directly related to physical fitness, which in turn was directly related to firefighter ability. Regression analyses showed that exercise intensity preference predicted variance in firefighter ability, and this relationship was statistically mediated by physical fitness levels. Firefighters with higher exercise intensity preference tended to have better physical fitness, which was associated with superior performance on firefighter tasks. Conclusions: These findings suggest that firefighters’ exercise intensity preferences play a key role in their physical fitness and, ultimately, their firefighting abilities. Assessing recruits’ exercise intensity preferences could help identify those who may struggle to maintain fitness, allowing for targeted interventions. Improving firefighters’ exercise intensity preference may be an effective strategy for enhancing their physical capabilities and job performance. Full article

This study focuses on the safe evacuation strategy and evacuation process in the subway train under the fires. The subway station evacuation mode should be adopted if the power system of a subway train is normal on fire. While, the tunnel evacuation mode should be adopted if the power system of the train fails because of the effects of fire. Under the tunnel evacuation mode, the direction of tunnel smoke should be opposite to that of most passengers, and passengers should be evacuated toward the fresh wind. By using the numerical simulation software Pathfinder and PyroSim, the passenger evacuation time under different conditions is calculated, and the safety of the evacuation process is evaluated. The results show that the evacuation time of the station evacuation mode is obviously shorter than that of the tunnel evacuation mode. With the same conditions, the evacuation time of the tunnel evacuation mode is 2193 s, which is about four times as much as the evacuation time of the station evacuation mode (526 s). The total evacuation time increases with the total number of passengers and the proportion of older people and children. Under an oil pool fire, which is an extreme fire condition, the fire environment inside the train may reach a level threatening the passengers’ safety before the evacuation is complete, even before the door opens; therefore, special attention should be paid to the safety issues in stage from the fire begins to the evacuation complete. Full article

Compliance with fire safety standards for wood is crucial for its application in the internal applications of buildings. This article focuses on monitoring the quality of protective coatings for wood under thermal loading conditions. The examined samples of spruce (Picea abies L. Karst.) and beech wood (Fagus sylvatica L.) were treated with selected fungicidal coatings based on dimethylbenzyl ammonium chloride. Following this, they were soaked in a ferric phosphate-based flame-retardant solution. Additionally, a portion of the samples was treated solely with the flame retardant. The effectiveness of the protective coatings was assessed through experimental thermal loading of the prepared samples. The testing method adhered to according to selected standards, which evaluate the ignitability of building materials when subjected to a small flame source. The experimental results, including the mass loss, mass loss rate, and time–temperature curves of the thermally loaded samples, demonstrated a significant influence of the selected coatings on thermal degradation. Notably, the fungicidal coating exhibited protective properties. Samples treated only with the flame retardant showed higher mass losses compared to those treated first with the fungicidal coating followed by the retardant. Additionally, differences were observed between the wood types, with beech samples exhibiting greater mass losses and higher mass loss rates than spruce. Full article

To investigate public perceptions regarding tunnel fire disasters and optimize the tunnel fire disaster prevention framework, this study takes the emerging social media platform Douyin as a case study, conducting an in-depth analysis of 2133 short videos related to tunnel fires on the platform. A computational communication method was used for analysis, Latent Dirichlet Allocation was used to cluster the discussion topics of these tunnel fire short videos, and a spatiotemporal evolution analysis of the number of videos posted, user comments, and emotional inclinations across different topics was performed. The findings reveal that there is a noticeable divergence in public opinion regarding emergency decision making in tunnel fires, related to the complexity of tunnel fire incidents, ethical dilemmas in tunnel fire escape scenarios, and insufficient knowledge popularization of fire safety practices. The study elucidates the public’s actual needs during tunnel fire incidents, and a dynamic disaster prevention framework for tunnel fires based on social media and artificial intelligence is proposed on this basis to enhance emergency response capabilities. Utilizing short videos on social media, the study constructs a critical target dataset under real tunnel fire scenarios. It proposes a computer vision-based model for identifying critical targets in tunnel fires. This model can accurately and in real-time identify key targets such as fires, smoke, vehicles, emergency exits, and people in real tunnel fire environments, achieving an average detection precision of 77.3%. This research bridges the cognitive differences between the general public and professionally knowledgeable tunnel engineers regarding tunnel fire evacuation, guiding tunnel fire emergency responses and personnel evacuation. Full article

This work presents experimental and numerical research on the pyrolysis and combustion characteristics of flame-retardant polycarbonate under low ambient pressure. A novel experimental low-pressure combustion platform was constructed to determine the heat release rate, a key combustion parameter of polycarbonate. The ignition process of polycarbonate under external radiation was analyzed, and an ignition time prediction model was developed. In addition, theoretical calculations of the main gas components and concentrations during the pyrolysis stage of polycarbonate and estimations of the calorific values of the combustible gas components produced during pyrolysis were carried out, providing a new explanation for the phenomenon of advancing ignition time in low-pressure environments. Full article

Fire accidents in electric vehicles are mainly caused by battery fires, and one of the most effective fire suppression methods is to spray water from the bottom of a vehicle in an upward direction. In this study, analyses and experiments were conducted to improve the spray angle of a fluidic oscillator used for attaching an upward spray device. Through these analyses, the factors resulting in the maximum spray angle were derived from the four design variables of the fluidic oscillator, which were reconstructed for further analysis. The model that combined the radius of the mixing chamber curvature, inlet wedge width, and outlet wedge width exhibited the largest spray angle (84°) among the combination models that included the outlet wedge width variable. To evaluate the fire suppression performance of the fluidic oscillator nozzle, a cooling-rate comparison experiment was conducted with a recently used orifice nozzle. The results showed that the fluidic oscillator nozzle leads to a faster overall cooling rate than the orifice nozzle, rendering it more suitable for suppressing battery fires. After the production of the upward spray device, practical tests showed that it could spray a large area under a vehicle, thereby suggesting its applicability in actual fire scenes. Full article

Background: Escape routes are important measures for firefighters to ensure their own safety, providing predetermined paths to safe areas. Their establishment needs to consider numerous factors, such as the timeliness and safety of the routes. Aims: Optimize the path planning method previously studied by our team to ensure the dynamic nature, timeliness, and safety of the routes. Methods: (1) Propose a comprehensive safety index that encompasses both spatial and temporal safety indices, providing a more holistic approach to route safety. (2) Introduce spatial adaptive factors and spatial safety windows corresponding to the spatial safety index within the comprehensive safety index. (3) Present a new concept, the “observation cycle”, as a standard for the frequency of updating wildfire spread information, thereby addressing the issue of a lack of real-time input information. Based on this, we propose a reliable dynamic update rule for its updating. Results: Compared to the unoptimized model, the final optimized model’s planned escape routes offer impressive dynamic performance, effectively guarding against sudden changes in wildfire conditions, enhancing route safety, and ensuring timeliness. Conclusions: This research ensures that firefighters can effectively guard against the threats posed by sudden changes in wildfire conditions when escaping in wildfire environments, while also guaranteeing timeliness and safety. Full article

This paper reports on research undertaken for the Building Resilience for Bushfire-Affected Communities in Noosa Shire project, funded by the Australian Government. Being evacuated from a home in the path of a bushfire can be traumatic. Therefore, it is important for evacuees to have safe places to stay, both physically and psychologically. Using a qualitative approach, we aimed to (a) understand the experiences of people who were displaced from their homes and sheltered at evacuation centres during the Noosa Shire bushfires and (b) understand what support is needed during disasters, such as bushfires, to help create positive experiences for future evacuees. Twelve participants displaced by bushfires in Noosa, Australia, in 2019 recalled their experiences in semi-structured interviews (conducted in 2022–2023). Inductive thematic analysis using NVivo 13 identified three themes that can inform government and public disaster preparation and response: planning, support, and communication. Findings from this study centred around building community resilience and offer valuable insights for organising disaster evacuation processes and evacuation centres on a broader scale. For individuals, it involves planning optimal evacuation routes, gathering necessary personal items, feeling safe and calm in evacuation centres, and receiving regular and accurate communication from authorities during disaster events. Full article