Fire | August 2024 - Browse Articles

20 pages, 6359 KiB

Open AccessReview

A Review of the Occurrence and Causes for Wildfires and Their Impacts on the Geoenvironment

by Arvin Farid, Md Khorshed Alam, Venkata Siva Naga Sai Goli, Idil Deniz Akin, Taiwo Akinleye, Xiaohui Chen, Qing Cheng, Peter Cleall, Sabatino Cuomo, Vito Foresta, Shangqi Ge, Luca Iervolino, Pierrette Iradukunda, Charles H. Luce, Eugeniusz Koda, Slobodan B. Mickovski, Brendan C. O’Kelly, Evan K. Paleologos, Dario Peduto, Evan John Ricketts, Mojtaba Sadegh, Theo S. Sarris, Devendra N. Singh, Prithvendra Singh, Chao-Sheng Tang, Guillermo Tardio, Magdalena Daria Vaverková, Max Veneris and Jan Winkler Show full author list Hide full author list

Fire 2024, 7(8), 295; https://doi.org/10.3390/fire7080295 - 22 Aug 2024

Cited by 10 | Viewed by 10614

Abstract

Wildfires have short- and long-term impacts on the geoenvironment, including the changes to biogeochemical and mechanical properties of soils, landfill stability, surface- and groundwater, air pollution, and vegetation. Climate change has increased the extent and severity of wildfires across the world. Simultaneously, anthropogenic [...] Read more.

Wildfires have short- and long-term impacts on the geoenvironment, including the changes to biogeochemical and mechanical properties of soils, landfill stability, surface- and groundwater, air pollution, and vegetation. Climate change has increased the extent and severity of wildfires across the world. Simultaneously, anthropogenic activities—through the expansion of urban areas into wildlands, abandonment of rural practices, and accidental or intentional fire-inception activities—are also responsible for a majority of fires. This paper provides an overall review and critical appraisal of existing knowledge about processes induced by wildfires and their impact on the geoenvironment. Burning of vegetation leads to loss of root reinforcement and changes in soil hydromechanical properties. Also, depending on the fire temperature, soil can be rendered hydrophobic or hydrophilic and compromise soil nutrition levels, hinder revegetation, and, in turn, increase post-fire erosion and the debris flow susceptibility of hillslopes. In addition to direct hazards, wildfires pollute air and soil with smoke and fire suppression agents releasing toxic, persistent, and relatively mobile contaminants into the geoenvironment. Nevertheless, the mitigation of wildfires’ geoenvironmental impacts does not fit within the scope of this paper. In the end, and in no exhaustive way, some of the areas requiring future research are highlighted. Full article

(This article belongs to the Collection Review Papers in Fire)

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17 pages, 5045 KiB

Open AccessArticle

The Impact of Corridor Directional Configuration on Wayfinding Behavior during Fire Evacuation in Underground Spaces: An Empirical Study Based on Virtual Reality

by Dachuan Wang, Ning Li, Silin Wu and Tiejun Zhou

Fire 2024, 7(8), 294; https://doi.org/10.3390/fire7080294 - 22 Aug 2024

Cited by 2 | Viewed by 1802

Abstract

This study employed Virtual Reality (VR) technology to investigate the influence of corridor directional configuration on evacuation wayfinding behavior in underground spaces. The study designed two virtual underground space fire evacuation scenarios with different forms of intersections, and recruited 115 volunteers to participate [...] Read more.

This study employed Virtual Reality (VR) technology to investigate the influence of corridor directional configuration on evacuation wayfinding behavior in underground spaces. The study designed two virtual underground space fire evacuation scenarios with different forms of intersections, and recruited 115 volunteers to participate in the experiment.The results indicated that corridor directional configuration significantly affected participants’ fire evacuation wayfinding behavior. At Y-shaped and T-shaped intersections with left and right turning options, participants showed a preference for choosing the right-side corridor. At ┡-shaped and ┩-shaped intersections with straight and turning options, participants tended to choose the straight path. Individual factors (such as gender, evacuation experience, and professional background) did not demonstrate significant effects on wayfinding choices in this study, though they may produce different evacuation outcomes in various scenarios. In practical evacuation design, corridor directional configuration should be organically integrated with other environmental factors to reinforce directional preferences and more effectively guide evacuation. The findings provide scientific evidence for underground space evacuation route design, which can be used to optimize evacuation signage and path configuration, thereby improving evacuation efficiency and safety. Future research could be conducted in more complex environments, considering additional variables to gain a more comprehensive understanding of evacuation behavior. Full article

(This article belongs to the Special Issue Fire Safety Management and Risk Assessment)

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18 pages, 9403 KiB

Open AccessArticle

Learning-Based Super-Resolution Imaging of Turbulent Flames in Both Time and 3D Space Using Double GAN Architectures

by Chenxu Zheng, Weiming Huang and Wenjiang Xu

Fire 2024, 7(8), 293; https://doi.org/10.3390/fire7080293 - 21 Aug 2024

Viewed by 1159

Abstract

This article presents a spatiotemporal super-resolution (SR) reconstruction model for two common flame types, a swirling and then a jet flame, using double generative adversarial network (GAN) architectures. The approach develops two sets of generator and discriminator networks to learn topographic and temporal [...] Read more.

This article presents a spatiotemporal super-resolution (SR) reconstruction model for two common flame types, a swirling and then a jet flame, using double generative adversarial network (GAN) architectures. The approach develops two sets of generator and discriminator networks to learn topographic and temporal features and infer high spatiotemporal resolution turbulent flame structure from supplied low-resolution counterparts at two time points. In this work, numerically simulated 3D turbulent swirling and jet flame structures were used as training data to update the model parameters of the GAN networks. The effectiveness of our model was then thoroughly evaluated in comparison to other traditional interpolation methods. An upscaling factor of 2 in space, which corresponded to an 8-fold increase in the total voxel number and a double time frame acceleration, was used to verify the model’s ability on a swirling flame. The results demonstrate that the assessment metrics, peak signal-to-noise ratio (PSNR), overall error (E_R), and structural similarity index (SSIM), with average values of 35.27 dB, 1.7%, and 0.985, respectively, in the spatiotemporal SR results, can reach acceptable accuracy. As a second verification to highlight the present model’s potential universal applicability to flame data of diverse types and shapes, we applied the model to a turbulent jet flame and had equal success. This work provides a different method for acquiring high-resolution 3D structure and further boosting repeat rate, demonstrating the potential of deep learning technology for combustion diagnosis. Full article

(This article belongs to the Special Issue Combustion Diagnostics)

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24 pages, 12280 KiB

Open AccessArticle

Wildland Firefighter Estimated Ground Evacuation Time Modeling to Support Risk-Informed Decision-Making

by Michael J. Campbell, Benjamin M. Gannon, Obaidur Rahman, Richard D. Stratton and Philip E. Dennison

Fire 2024, 7(8), 292; https://doi.org/10.3390/fire7080292 - 20 Aug 2024

Cited by 1 | Viewed by 2104

Abstract

Wildland firefighters often work in remote settings with multiple hazards that can cause life-threatening injuries. Prompt access to medical care is key to reducing injury consequences. For the last decade, a spatial model of wildland firefighter estimated ground evacuation time (GET) has been [...] Read more.

Wildland firefighters often work in remote settings with multiple hazards that can cause life-threatening injuries. Prompt access to medical care is key to reducing injury consequences. For the last decade, a spatial model of wildland firefighter estimated ground evacuation time (GET) has been used when developing operational response strategies in the contiguous United States (CONUS). This paper describes our updated and improved GET model and the resulting decision support spatial data representing the estimated time to evacuate to a hospital from anywhere within the CONUS using ground transportation only. The new GET model leverages updated input datasets and has improved off-road travel time estimation methods that incorporate the latest science on how terrain slope influences pedestrian travel rates. It also accounts for a novel set of landscape variables not previously considered, including minor roads and trails, streams, woody debris, cliffs, and an improved handling of shrub cover. When compared to a set of recent safety incidents, the reported evacuation times were correlated with the model predictions. The spatial patterns of GET from the new model are similar to the old product; however, we found that, on average, the new version of GET yields slightly faster evacuation times, but with regional variation in this trend. Full article

(This article belongs to the Section Mathematical Modelling and Numerical Simulation of Combustion and Fire)

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21 pages, 1533 KiB

Open AccessArticle

The Impact of Firefighters’ Emotional Labor on Job Performance: The Moderating Effects of Transactional and Transformational Leadership

by Hyeong-Su Park, Kuk-Kyoung Moon and Tae-Soo Ha

Fire 2024, 7(8), 291; https://doi.org/10.3390/fire7080291 - 20 Aug 2024

Cited by 1 | Viewed by 2761

Abstract

Our study leverages insights from the conservation of resources theory and job demands–resources theory to explore the relationship between two types of emotional labor—surface acting and deep acting—and job performance among firefighters. Furthermore, we assess the moderating roles of transactional and transformational leadership [...] Read more.

Our study leverages insights from the conservation of resources theory and job demands–resources theory to explore the relationship between two types of emotional labor—surface acting and deep acting—and job performance among firefighters. Furthermore, we assess the moderating roles of transactional and transformational leadership within this framework. Using hierarchical multiple regression models, we analyzed data from 1453 firefighters in Gyeonggi-do, South Korea’s most populous province. The findings reveal that surface acting adversely affects job performance, whereas deep acting exerts no significant impact. The relationships between these two types of emotional labor are contingent on transactional and transformational leadership. The policy implications of this study include the need to manage employees’ emotional labor by distinguishing between surface and deep acting as well as the need for efforts and alternatives to facilitate transactional and transformational leadership. Full article

(This article belongs to the Section Fire Social Science)

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16 pages, 6304 KiB

Open AccessArticle

Effect of Initial Temperature and Pressure on the Explosion Characteristics and Intermediate Reaction Products of Formic Acid Mixtures: A Theoretical Study

by Maria Mitu

Fire 2024, 7(8), 290; https://doi.org/10.3390/fire7080290 - 19 Aug 2024

Cited by 1 | Viewed by 1789

Abstract

Formic acid is a promising candidate fuel that can be produced by reacting renewable hydrogen with carbon dioxide. However, the burning safety characteristics of formic acid–air mixtures have not been fully studied. This paper presents an extensive theoretical study of the adiabatic explosion [...] Read more.

Formic acid is a promising candidate fuel that can be produced by reacting renewable hydrogen with carbon dioxide. However, the burning safety characteristics of formic acid–air mixtures have not been fully studied. This paper presents an extensive theoretical study of the adiabatic explosion pressure of formic acid–air premixed laminar flames at various initial conditions (composition of formic acid: 17–38% volume; initial pressure: 0.1–1.5 bar; initial temperature: 333–500 K), using the GASEQ software package. GASEQ software calculates chemical equilibria based on ideal gas behavior and is based on the hypothesis of adiabatic expansion inside a closed containment that allows ideal expansion. The influence of the initial conditions (pressure, temperature, and concentration) of formic acid–air mixtures on the adiabatic explosion pressures, maximum flame temperature, and peak concentrations of the main reaction intermediates is investigated and discussed. It is found that the adiabatic peak explosion pressure (calculated equilibrium pressure) of the studied concentrations decreases with increasing initial temperature and increases linearly with increasing initial pressure. Full article

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17 pages, 3656 KiB

Open AccessArticle

Numerical Investigation of the Combustion Characteristics of a Hydrogen-Fueled Engine with Water Injection

by Qinghe Yao, Hongbo Lu, Junyi Chen and Trevor Hocksun Kwan

Fire 2024, 7(8), 289; https://doi.org/10.3390/fire7080289 - 19 Aug 2024

Viewed by 1605

Abstract

The quest for clean, efficient engine technologies is imperative in reducing transportation’s environmental impact. Hydrogen, as a zero-emission fuel, offers significant potential for internal combustion engines but faces challenges such as optimizing engine performance and longevity. Water injection is proposed as a solution, [...] Read more.

The quest for clean, efficient engine technologies is imperative in reducing transportation’s environmental impact. Hydrogen, as a zero-emission fuel, offers significant potential for internal combustion engines but faces challenges such as optimizing engine performance and longevity. Water injection is proposed as a solution, yet its effects on engine performance require thorough investigation. This study bridges the knowledge gap by examining various water injection ratios (WIRs) and their impact on engine performance, focusing on the balance between power output and engine longevity. We identified the existence of an optimum WIR (e.g., 10% in this study), which provides peak performance with minimal adverse effects on engine performance and health. Computational simulations of a single-cylinder engine revealed how WIRs influence in-cylinder temperature, pressure, and IMEP, emphasizing the nuanced benefits of water injection. Additionally, our analysis of turbulence, through TKE and dissipation rate, deepens the understanding of combustion and fuel efficiency in hydrogen engines. This research provides valuable guidance for optimizing engine operations and paves the way for advanced water injection systems in hydrogen engines, marking a significant step towards cleaner engine technology. Full article

(This article belongs to the Special Issue Hydrogen Safety: Challenges and Opportunities)

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14 pages, 5355 KiB

Open AccessTechnical Note

Fire Resistance in Screwed and Hollow Core Wooden Elements Filled with Insulating Material

by Miguel Osório, Elza M. M. Fonseca and Domingos Pereira

Fire 2024, 7(8), 288; https://doi.org/10.3390/fire7080288 - 17 Aug 2024

Cited by 4 | Viewed by 1061

Abstract

This study looks at wall partition panels with hollow core wood elements and gypsum board as protection in fire conditions. In addition to our previous research, this study on wall partitions considers the effect of steel screws in the assembly of the elements, [...] Read more.

This study looks at wall partition panels with hollow core wood elements and gypsum board as protection in fire conditions. In addition to our previous research, this study on wall partitions considers the effect of steel screws in the assembly of the elements, as well as the filling of the cavity with insulating material. The goal of this work is to calculate the fire resistance time and compare the results using different numerical models. The discussion of the results analyzes the effect of steel screws and the introduction of insulating material inside the cavities. The steel screws are verified with and without threads. The numerical models are based on the finite element method, using thermal and transient analysis with nonlinear materials. The thermal insulation criterion for measuring fire resistance is referenced by the EN 1363-1:2020 standard. The steel screws allow more heat to be concentrated and, therefore, distribute it throughout the wooden wall partition members. Based on the results obtained, the use of steel screws reduces fire resistance by 71.75 min, regardless of whether the wall partition is filled with or without insulating material. Full article

(This article belongs to the Section Fire Risk Assessment and Safety Management in Buildings and Urban Spaces)

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20 pages, 4743 KiB

Open AccessArticle

Hazardous Chemical Laboratory Fire Risk Assessment Based on ANP and 3D Risk Matrix

by Changmao Qi, Qifeng Zou, Yu Cao and Mingyuan Ma

Fire 2024, 7(8), 287; https://doi.org/10.3390/fire7080287 - 16 Aug 2024

Cited by 2 | Viewed by 1800

Abstract

The laboratory is a high-risk place for scientific research and learning, and there are many risk factors and great potential for harm. Hazardous chemicals are important to consider and are the key objects to monitor in a laboratory. In recent years, hazardous chemical [...] Read more.

The laboratory is a high-risk place for scientific research and learning, and there are many risk factors and great potential for harm. Hazardous chemicals are important to consider and are the key objects to monitor in a laboratory. In recent years, hazardous chemical fire accidents have occurred in laboratories in various industries, bringing painful lessons and making it urgent to strengthen the safety management of hazardous laboratory chemicals. In this study, a semi-quantitative comprehensive risk assessment model for hazardous chemical laboratory fires was constructed by combining the bowtie model, three-dimensional risk matrix, and analytic network process (ANP). This study applied this method to the management of hazardous chemicals at the TRT Research Institute; evaluated the probability, severity, and preventive components of the corresponding indicators by constructing different index systems; and calculated the evaluation results using the weight of each index. The evaluation results show that the comprehensive likelihood level is 2, the comprehensive severity level is 3, the comprehensive preventive level is 3, and the final calculated comprehensive risk level is tolerable (II). Based on the results of the risk assessment, the corresponding control measures that can reduce the fire risk of hazardous chemicals in the laboratory are proposed according to the actual situation at the TRT Research Institute. Full article

(This article belongs to the Special Issue Fire Safety Management and Risk Assessment)

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17 pages, 6274 KiB

Open AccessArticle

Enhanced Automatic Wildfire Detection System Using Big Data and EfficientNets

by Armando Fernandes, Andrei Utkin and Paulo Chaves

Fire 2024, 7(8), 286; https://doi.org/10.3390/fire7080286 - 16 Aug 2024

Cited by 3 | Viewed by 1871

Abstract

Previous works have shown the effectiveness of EfficientNet—a convolutional neural network built upon the concept of compound scaling—in automatically detecting smoke plumes at a distance of several kilometres in visible camera images. Building on these results, we have created enhanced EfficientNet models capable [...] Read more.

Previous works have shown the effectiveness of EfficientNet—a convolutional neural network built upon the concept of compound scaling—in automatically detecting smoke plumes at a distance of several kilometres in visible camera images. Building on these results, we have created enhanced EfficientNet models capable of precisely identifying the smoke location due to the introduction of a mosaic-like output and achieving extremely reduced false positive percentages due to using partial AUROC and applying class imbalance. Our EfficientNets beat InceptionV3 and MobileNetV2 in the same dataset and achieved a true detection percentage of 89.2% and a false positive percentage of only 0.306% across a test set with 17,023 images. The complete dataset used in this study contains 26,204 smoke and 51,075 non-smoke images. This makes it one of the largest, if not the most extensive, datasets reported in the scientific literature for smoke plume imagery. So, the achieved percentages are not only among the best reported for this application but are also among the most reliable due to the extent and representativeness of the dataset. Full article

(This article belongs to the Special Issue Intelligent Fire Protection)

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24 pages, 12986 KiB

Open AccessArticle

The Impact of Fuel Thinning on the Microclimate in Coastal Rainforest Stands of Southwestern British Columbia, Canada

by Rhonda L. Millikin, W. John Braun, Martin E. Alexander and Shabnam Fani

Fire 2024, 7(8), 285; https://doi.org/10.3390/fire7080285 - 14 Aug 2024

Cited by 1 | Viewed by 3377

Abstract

Prescriptions for fuel management are universally applied across the forest types in British Columbia, Canada, to reduce the fire behaviour potential in the wildland–urban interface. Fuel thinning treatments have been advocated as a means of minimizing the likelihood of crown fire development in [...] Read more.

Prescriptions for fuel management are universally applied across the forest types in British Columbia, Canada, to reduce the fire behaviour potential in the wildland–urban interface. Fuel thinning treatments have been advocated as a means of minimizing the likelihood of crown fire development in conifer forests. We hypothesized that these types of prescriptions are inappropriate for the coastal rainforests of the Whistler region of the province. Our study examined the impact of fuel thinning treatments in four stands located in the Whistler community forest. We measured several in-stand microclimatic variables beginning with snow melt in the spring up to the height of fire danger in late summer, at paired thinned and unthinned stand locations. We found that the thinning led to warmer, drier, and windier fire environments. The difference in mean soil moisture, ambient air temperature, and relative humidity between thinned and unthinned stands was significant in the spring with approximate p-values of 0.000217, 9.40 × 10⁻⁵, and 4.33 × 10⁻⁸, respectively, though there were no discernible differences in the late summer. The difference in mean solar radiation, average wind speed, and average cross wind between thinned and unthinned locations are significant in the spring and late summer (with approximate p-values for spring of 9.54 × 10⁻⁷, 0.02101, 1.92 × 10⁻⁹, and for late summer of 2.45 × 10⁻⁷, 4.08 × 10⁻⁶, and 2.45 × 10⁻⁵, respectively). Full article

(This article belongs to the Section Fire Research at the Science–Policy–Practitioner Interface)

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17 pages, 24883 KiB

Open AccessArticle

Synergistic Effects of Titanium-Based MOFs MIL-125 with Intumescent Flame Retardants in ABS Polymer Composites on Flame Retardancy Study

by Zhuoran Zhang, Yufeng Quan, Ruiqing Shen, Kun-Yu Wang, Hong-Cai Zhou and Qingsheng Wang

Fire 2024, 7(8), 284; https://doi.org/10.3390/fire7080284 - 14 Aug 2024

Viewed by 1968

Abstract

The intumescent flame retardant (IFR) technique is an alternative to halogen-based flame retardants for reducing fire hazards in polymers. However, IFR has drawbacks like unsatisfactory flame-retardant efficiency and high loading requirements. In this study, MIL-125 (Ti-based metal–organic framework) is added to ABS/IFR composites [...] Read more.

The intumescent flame retardant (IFR) technique is an alternative to halogen-based flame retardants for reducing fire hazards in polymers. However, IFR has drawbacks like unsatisfactory flame-retardant efficiency and high loading requirements. In this study, MIL-125 (Ti-based metal–organic framework) is added to ABS/IFR composites to improve flame retardancy and reduce smoke emissions. Thermogravimetric analysis (TGA) results indicate that combining ammonium polyphosphate (APP) and expandable graphite (EG) increases charred residue and slows mass loss compared with the original ABS resin. The ABS/IFR/MIL-125 system stabilizes the char layer, serving as a protective shield against combustible gases during combustion. Additionally, MIL-125 enhances performance in microscale combustion calorimetry (MCC) flammability testing. In fire tests (UL-94, limiting oxygen index (LOI), and cone calorimeter), the ABS/IFR/MIL-125 system achieves a UL-94 V0 rating and the highest LOI value of 31.5% ± 0.1%. Peak heat lease rate (PHRR) values in the cone calorimeter are reduced by 72% with 20 wt.% of additives, and smoke production decreases by 53% compared with neat ABS. These results demonstrate the efficient synergistic effects of MIL-125 and IFR additives in improving the formation and stability of the intumescent char layer, thereby protecting ABS from intense burning. Full article

(This article belongs to the Special Issue Fire Hazard of Polymer Composites and Nanocomposites)

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15 pages, 2795 KiB

Open AccessArticle

Study on the Influence Mechanism of the Key Active Structure of Coal Molecules on Spontaneous Combustion Characteristics Based on Extraction Technology

by Jun Guo, Yunfei Wu, Yin Liu, Guobin Cai, Dailin Li and Yan Jin

Fire 2024, 7(8), 283; https://doi.org/10.3390/fire7080283 - 13 Aug 2024

Viewed by 1484

Abstract

The molecular structure of coal is complex, and the existing research methods are limited, so it is difficult to clarify its influence mechanism on the spontaneous-combustion characteristics of coal. In this paper, the previous extraction, FTIR, TPR, TG-DSC and other experimental results are [...] Read more.

The molecular structure of coal is complex, and the existing research methods are limited, so it is difficult to clarify its influence mechanism on the spontaneous-combustion characteristics of coal. In this paper, the previous extraction, FTIR, TPR, TG-DSC and other experimental results are combined to analyze the extraction weakening effect and the correlation analysis of the spontaneous-combustion characteristic parameters of raffinate coal. The results show that extraction can destroy the connection bond of coal molecules, change the content of dominant active groups in the coal spontaneous-combustion reaction, increase the lower limit of the key temperature nodes of coal spontaneous-combustion or extend the temperature range, resulting in an increase in the ignition-point temperature of coal and a decrease in coal quality. This paper will provide a theoretical basis for the study of the microscopic mechanism of coal spontaneous-combustion and then provide new ideas for the development of an active prevention and control technology for coal spontaneous-combustion. Full article

(This article belongs to the Special Issue Simulation, Experiment and Modeling of Coal Fires)

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12 pages, 4115 KiB

Open AccessArticle

Does Fire Influence the Greenness Index of Trees? Twelve Months to Decode the Answer in a Rarámuri Mixed Forest

by Marín Pompa-García, Felipa de Jesús Rodríguez-Flores, José A. Sigala and Dante Arturo Rodríguez-Trejo

Fire 2024, 7(8), 282; https://doi.org/10.3390/fire7080282 - 13 Aug 2024

Cited by 1 | Viewed by 1594

Abstract

Fire is one of the most significant agents of disturbance in forest ecosystems, with implications for their structure and composition. An understanding of its dynamics is essential for the delineation of forest management policies in the context of predicted climate scenarios. Based on [...] Read more.

Fire is one of the most significant agents of disturbance in forest ecosystems, with implications for their structure and composition. An understanding of its dynamics is essential for the delineation of forest management policies in the context of predicted climate scenarios. Based on the monthly monitoring of greenness index (NDVI) values recorded over one year at the individual crown level, this study aimed to analyze the dynamics of NDVI values for four different genera, growing in a Mexican mixed forest and subjected to a prescribed burn, relative to those of a control (unburned) treatment. The results demonstrated the general effect of burning over time on NDVI values among the genera, with Pinus showing the most significant effect, while the effect on Quercus was not significant. Tree height was related to NDVI values for Pinus and Juniperus in the burned area, where low-growing individuals responded negatively in terms of greenness index values. Further studies are still required, but we can conclude that fire plays a differential role in the dynamics of canopy activity and that tree size is an important variable. The results also contribute to our understanding of forest responses to fire disturbance, providing indicators with which to assess ecosystem stability under the threat of extreme climatic variations. Full article

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14 pages, 5084 KiB

Open AccessArticle

Impact of Jet Fires on Steel Structures: Application of Passive Fire Protection Materials

by Marina Gravit, Dmitry Korolchenko, Ekaterina Nedviga, Fedor Portnov and Semen Diachenko

Fire 2024, 7(8), 281; https://doi.org/10.3390/fire7080281 - 9 Aug 2024

Cited by 3 | Viewed by 1982

Abstract

Jet fires are the second most common fire scenario after spill fires. This type of fire is characteristic of gas and gas–oil fires occurring on oil platforms and gas production and processing plants. The consequences of such fires are characterized by high material [...] Read more.

Jet fires are the second most common fire scenario after spill fires. This type of fire is characteristic of gas and gas–oil fires occurring on oil platforms and gas production and processing plants. The consequences of such fires are characterized by high material damage; this is associated with extensive networks of technological communications, since there is a high density of technological facilities and installations in the territory where these fires occur. At such facilities, there is a large number of steel structures, which under the action of high temperature quickly lose their strength and deform. To protect steel structures in the oil and gas industry, fire protection is used, which consists of different types: boards in the form of flat plates, plasters, and epoxy paints. This paper compares three types of fire protection materials for steel structures under jet fire: board fireproofing, plaster composition, and epoxy coating. When comparing the efficiency in jet fire, cement boards were found to be the best. However, despite the better fire protection efficiency, their low application is expected due to their massiveness and the high cost of such protection and the difficulty of installation. Nevertheless, the development of fire depends on the place of its origin, the size of the initial fire zone, and the stability and massiveness of the metal elements of the vessel structure or the structure of the boards on which the equipment can be placed. Therefore, it is necessary to take these factors into account when selecting fire protection and to apply it depending on the required fire resistance limits of structures, which should be determined depending on the fire development scenarios. Full article

(This article belongs to the Special Issue Thermal–Mechanical Analysis Applied in Materials under Fire Conditions)

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15 pages, 4739 KiB

Open AccessArticle

Impacts of Fire Frequency on Net CO₂ Emissions in the Cerrado Savanna Vegetation

by Letícia Gomes, Jéssica Schüler, Camila Silva, Ane Alencar, Bárbara Zimbres, Vera Arruda, Wallace Vieira da Silva, Edriano Souza, Julia Shimbo, Beatriz Schwantes Marimon, Eddie Lenza, Christopher William Fagg, Sabrina Miranda, Paulo Sérgio Morandi, Ben Hur Marimon-Junior and Mercedes Bustamante

Fire 2024, 7(8), 280; https://doi.org/10.3390/fire7080280 - 9 Aug 2024

Cited by 3 | Viewed by 2746

Abstract

Savannas play a key role in estimating emissions. Climate change has impacted the Cerrado savanna carbon balance. We used the burned area product and long-term field inventories on post-fire vegetation regrowth to estimate the impact of the fire on greenhouse gas emissions and [...] Read more.

Savannas play a key role in estimating emissions. Climate change has impacted the Cerrado savanna carbon balance. We used the burned area product and long-term field inventories on post-fire vegetation regrowth to estimate the impact of the fire on greenhouse gas emissions and net carbon dioxide (CO₂) emissions in the Cerrado savanna between 1985 and 2020. We estimated the immediate emissions from fires, CO₂ emissions by plant mortality, and CO₂ removal from vegetation regrowth. The burned area was 29,433 km²; savanna fires emitted approximately 2,227,964 Gg of CO₂, 85,057 Gg of CO, 3010 Gg of CH₄, 5,103 Gg of NO_x, and 275 Gg of N₂O. We simulated vegetation regrowth according to three fire regime scenarios: extreme (high fire frequency and short fire interval), intermediate (medium fire frequency and medium fire interval), and moderate (low fire frequency and long fire interval). Under the extreme and intermediate scenarios, the vegetation biomass decreased by 2.0 and 0.4% (ton/ha-year), while the biomass increased by 2.1% under a moderate scenario. We converted this biomass into CO₂ and showed that the vegetation regrowth removed 63.5% of the total CO₂ emitted (2,355,426 Gg), indicating that the Cerrado savanna has been a source of CO₂ to the atmosphere. Full article

(This article belongs to the Section Fire Science Models, Remote Sensing, and Data)

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27 pages, 1903 KiB

Open AccessArticle

Assessing the Effect of Community Preparedness on Property Damage Costs during Wildfires: A Case Study of Greece

by Stavros Kalogiannidis, Dimitrios Kalfas, Theoxaris Zagkas and Fotios Chatzitheodoridis

Fire 2024, 7(8), 279; https://doi.org/10.3390/fire7080279 - 8 Aug 2024

Cited by 2 | Viewed by 2277

Abstract

The current study attempts to assess the effect of community preparedness on property damage costs during wildfires. The focus is primarily on how various aspects of community preparedness, such as early warning systems, early risk assessment, emergency response plans, and fire-resistant landscaping, influence [...] Read more.

The current study attempts to assess the effect of community preparedness on property damage costs during wildfires. The focus is primarily on how various aspects of community preparedness, such as early warning systems, early risk assessment, emergency response plans, and fire-resistant landscaping, influence the extent of property damage costs during wildfires. For this purpose, data were collected from 384 Greek residents from different regions of the country using an online questionnaire. In this case, analysis was performed utilizing SPSS version 22.0. According to the findings, survey respondents replied that fire suppression was the most common property cost associated with wildfire. The study contributes to existing knowledge by providing insights into the specific factors that affect property damage expenditure during wildfires, specifically the intricate relationship between the expenses of property loss caused by wildfires and community preparation. The study’s findings can be utilized by policymakers and communities to improve preparedness plans and consequently decrease the impact of wildfires on property and people. Full article

(This article belongs to the Special Issue Forest Fuel Treatment and Fire Risk Assessment)

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24 pages, 4089 KiB

Open AccessArticle

Forest Fires: Silvicultural Prevention and Mathematical Models for Predicting Fire Propagation in Southern Italy

by Pasquale A. Marziliano, Fabio Lombardi, Maria F. Cataldo, Michele Mercuri, Salvatore F. Papandrea, Leonardo M. Manti, Silvio Bagnato, Giuseppe Alì, Pierpaolo Fusaro, Pietro S. Pantano and Carmelo Scuro

Fire 2024, 7(8), 278; https://doi.org/10.3390/fire7080278 - 7 Aug 2024

Cited by 5 | Viewed by 1860

Abstract

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 [...] Read more.

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. Full article

(This article belongs to the Special Issue Applications of Computational Statistics to Wildfire Science and Management)

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17 pages, 1946 KiB

Open AccessArticle

Data-Driven PM_2.5 Exposure Prediction in Wildfire-Prone Regions and Respiratory Disease Mortality Risk Assessment

by Sadegh Khanmohammadi, Mehrdad Arashpour, Milad Bazli and Parisa Farzanehfar

Fire 2024, 7(8), 277; https://doi.org/10.3390/fire7080277 - 7 Aug 2024

Viewed by 1762

Abstract

Wildfires generate substantial smoke containing fine particulate matter (PM_2.5) that adversely impacts health. This study develops machine learning models integrating pre-wildfire factors like weather and fuel conditions with post-wildfire health impacts to provide a holistic understanding of smoke exposure risks. Various [...] Read more.

Wildfires generate substantial smoke containing fine particulate matter (PM_2.5) that adversely impacts health. This study develops machine learning models integrating pre-wildfire factors like weather and fuel conditions with post-wildfire health impacts to provide a holistic understanding of smoke exposure risks. Various data-driven models including Support Vector Regression, Multi-layer Perceptron, and three tree-based ensemble algorithms (Random Forest, Extreme Gradient Boosting (XGBoost), and Natural Gradient Boosting (NGBoost)) are evaluated in this study. Ensemble models effectively predict PM_2.5 levels based on temperature, humidity, wind, and fuel moisture, revealing the significant roles of radiation, temperature, and moisture. Further modelling links smoke exposure to deaths from chronic obstructive pulmonary disease (COPD) and lung cancer using age, sex, and pollution type as inputs. Ambient pollution is the primary driver of COPD mortality, while age has a greater influence on lung cancer deaths. This research advances atmospheric and health impact understanding, aiding forest fire prevention and management. Full article

(This article belongs to the Special Issue Forest Fuel Treatment and Fire Risk Assessment)

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21 pages, 14182 KiB

Open AccessArticle

Transferability of Empirical Models Derived from Satellite Imagery for Live Fuel Moisture Content Estimation and Fire Risk Prediction

by Eva Marino, Lucía Yáñez, Mercedes Guijarro, Javier Madrigal, Francisco Senra, Sergio Rodríguez and José Luis Tomé

Fire 2024, 7(8), 276; https://doi.org/10.3390/fire7080276 - 6 Aug 2024

Cited by 1 | Viewed by 2085

Abstract

Estimating live fuel moisture content (LFMC) is critical for assessing vegetation flammability and predicting potential fire behaviour, thus providing relevant information for wildfire prevention and management. Previous research has demonstrated that empirical modelling based on spectral data derived from remote sensing is useful [...] Read more.

Estimating live fuel moisture content (LFMC) is critical for assessing vegetation flammability and predicting potential fire behaviour, thus providing relevant information for wildfire prevention and management. Previous research has demonstrated that empirical modelling based on spectral data derived from remote sensing is useful for retrieving LFMC. However, these types of models are often very site-specific and generally considered difficult to extrapolate. In the present study, we analysed the performance of empirical models based on Sentinel-2 spectral data for estimating LFMC in fire-prone shrubland dominated by Cistus ladanifer. We used LFMC data collected in the field between June 2021 and September 2022 in 27 plots in the region of Andalusia (southern Spain). The specific objectives of the study included (i) to test previous existing models fitted for the same shrubland species in a different study area in the region of Madrid (central Spain); (ii) to calibrate empirical models with the field data from the region of Andalusia, comparing the model performance with that of existing models; and (iii) to test the capacity of the best empirical models to predict decreases in LFMC to critical threshold values in historical wildfire events. The results showed that the empirical models derived from Sentinel-2 data provided accurate LFMC monitoring, with a mean absolute error (MAE) of 15% in the estimation of LFMC variability throughout the year and with the MAE decreasing to 10% for the critical lower LFMC values (<100%). They also showed that previous models could be easily recalibrated for extrapolation to different geographical areas, yielding similar errors to the specific empirical models fitted in the study area in an independent validation. Finally, the results showed that decreases in LFMC in historical wildfire events were accurately predicted by the empirical models, with LFMC <80% in this fire-prone shrubland species. Full article

(This article belongs to the Special Issue Integrated Vulnerability of Forest Systems to Wildfire: Implications on Forest Management Tools. VIS4FIRE Project)

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11 pages, 13027 KiB

Open AccessArticle

Experimental Study on Explosion Characteristics of LPG/Air Mixtures Suppressed by CO₂ Synergistic Inert Powder

by Enlai Zhao, Zhentang Liu, Song Lin and Xiaomeng Chu

Fire 2024, 7(8), 275; https://doi.org/10.3390/fire7080275 - 6 Aug 2024

Cited by 1 | Viewed by 1566

Abstract

In order to study the explosion suppression characteristics of LPG/air mixture by CO₂ synergistic inert powder, explosion suppression experiments were conducted in a 20 L explosion device. The results show that the explosion suppression effect of NaHCO₃ powder is prior to [...] Read more.

In order to study the explosion suppression characteristics of LPG/air mixture by CO₂ synergistic inert powder, explosion suppression experiments were conducted in a 20 L explosion device. The results show that the explosion suppression effect of NaHCO₃ powder is prior to Al(OH)₃ powder under the condition of no CO₂ synergy. As the mass concentration of inert powder increases, the peak value of explosion pressure P_ex and the peak value of the pressure rise rate (dP/dt)_ex decrease, and the explosion suppression effect gradually enhances. Gas–solid two-phase inhibitors exhibit more significant inhibitory effects than single-phase inhibitors. Increasing the volume fraction of CO₂ or the mass concentration of inert powder can improve the explosion suppression effect. The explosion suppression effect of CO₂/NaHCO₃ is significantly better than that of CO₂/Al(OH)₃. The research results have certain significance for the prevention and control of LPG explosion accidents. Full article

(This article belongs to the Special Issue Investigation of Combustion Dynamics and Flame Properties of Fuel)

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15 pages, 7751 KiB

Open AccessArticle

Study on the Natural Smoke Exhaust Performance of Board-Coupled Vertical Shaft in High-Altitude Tunnel Fires

by Zihe Gao, Pengju Zhao, Zhaoguo Wu, Jiajun Cai and Linjie Li

Fire 2024, 7(8), 274; https://doi.org/10.3390/fire7080274 - 6 Aug 2024

Cited by 2 | Viewed by 1495

Abstract

Vertical shaft natural ventilation is a common smoke exhaust method in highway tunnel fires. This study investigated the vertical shaft natural smoke exhaust work in highway tunnel fires with the effect of multiple factors through numerical simulation. Using the analysis of the flow [...] Read more.

Vertical shaft natural ventilation is a common smoke exhaust method in highway tunnel fires. This study investigated the vertical shaft natural smoke exhaust work in highway tunnel fires with the effect of multiple factors through numerical simulation. Using the analysis of the flow field of smoke in nearby areas of the vertical shaft and the quantitative calculation of the gas exhausted through the vertical shaft, considering the impact of shaft division and board height, an optimal vertical shaft arrangement was proposed, and the working conditions of this arrangement in low-pressure environments were discussed. The results show that dividing a single large vertical shaft into multiple small vertical shafts and appropriately adjusting the board height can reduce the incidence of vertical shaft plug holes and significantly enhance the vertical shaft smoke exhaust performance. Meanwhile, the board-coupled shaft (BCS) has excellent working ability in low-pressure environments, and when pressure drops, smoke exhaust efficiency will improve. This research offers a foundation and reference value for improving the vertical shaft smoke exhaust system in highway tunnels. Full article

(This article belongs to the Special Issue Advances in Industrial Fire and Urban Fire Research)

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18 pages, 5604 KiB

Open AccessArticle

Study on the Fire Characteristics of Dual Fire Sources and the Difference in Power Temperature of Different Fire Sources in Tunnel

by Xiaokun Zhao, Minghao Ni, Wencai Wang, Hongwei Wang and Jianing Wang

Fire 2024, 7(8), 273; https://doi.org/10.3390/fire7080273 - 6 Aug 2024

Cited by 1 | Viewed by 1515

Abstract

To investigate the combustion characteristics of multiple fire sources in the tunnel caused by ‘jumping’ discontinuous fire spread, we utilized scaled model experiments, numerical simulation software, and theoretical research. Our study focused on analyzing the influence of different fire source powers on the [...] Read more.

To investigate the combustion characteristics of multiple fire sources in the tunnel caused by ‘jumping’ discontinuous fire spread, we utilized scaled model experiments, numerical simulation software, and theoretical research. Our study focused on analyzing the influence of different fire source powers on the temperature characteristics of double fire sources in the tunnel. We examined the temperature characteristics, critical wind speed, and change rule under various wind speeds, fire source spacing, and fire source powers. Additionally, we explored the temperature characteristics, critical wind speed, and change rule of different fire source powers under varying wind speed conditions. The mathematical model for roof temperature decay and the temperature decay coefficients of dual source fires were established through the analysis of scale-down model experiments and numerical simulations. In comparison to single-source fires, the temperature variations in the tunnel of dual source fires exhibit a more intricate pattern, with higher average temperature and temperature peak values. These values are influenced by factors such as fire source spacing and power. Numerical simulation software was utilized to investigate the impact of fire source spacing at 10 m, 15 m, and 20 m, as well as the effect of varying fire source power on the temperature distribution within a tunnel under consistent fire source position and growth coefficient. The study revealed that, with consistent double fire source position and ventilation conditions in the tunnel, the upstream fire source exhibited greater power than the downstream fire source, resulting in the lowest average and peak temperatures in the tunnel. This observation could potentially enhance escape and rescue operations within the tunnel. Similarly, the lowest average and peak temperatures in the tunnel were also identified, offering potential benefits for optimizing escape and rescue strategies in tunnel scenarios. Full article

(This article belongs to the Special Issue Fire Numerical Simulation)

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25 pages, 5377 KiB

Open AccessArticle

Investigating FWI Moisture Codes in Relation to Satellite-Derived Soil Moisture Data across Varied Resolutions

by Hatice Atalay, Ayse Filiz Sunar and Adalet Dervisoglu

Fire 2024, 7(8), 272; https://doi.org/10.3390/fire7080272 - 5 Aug 2024

Cited by 1 | Viewed by 1484

Abstract

In the Mediterranean region, particularly in Antalya, southern Türkiye, rising forest fire risks due to climate change threaten ecosystems, property, and lives. Reduced soil moisture during the growing season is a key factor increasing fire risk by stressing plants and lowering fuel moisture [...] Read more.

In the Mediterranean region, particularly in Antalya, southern Türkiye, rising forest fire risks due to climate change threaten ecosystems, property, and lives. Reduced soil moisture during the growing season is a key factor increasing fire risk by stressing plants and lowering fuel moisture content. This study assessed soil moisture and fuel moisture content (FMC) in ten fires (2019–2021) affecting over 50 hectares. The Fire Weather Index (FWI) and its components (FFMC, DMC, DC) were calculated using data from the General Directorate of Meteorology, EFFIS (8 km), and ERA5 (≈28 km) satellite sources. Relationships between FMCs, satellite-based soil moisture datasets (SMAP, SMOS), and land surface temperature (LST) data (MODIS, Landsat 8) were analyzed. Strong correlations were found between FWI codes and satellite soil moisture, particularly with SMAP. Positive correlations were observed between LST and FWIs, while negative correlations were evident with soil moisture. Statistical models integrating in situ soil moisture and EFFIS FWI (R: −0.86, −0.84, −0.83 for FFMC, DMC, DC) predicted soil moisture levels during extended fire events effectively, with model accuracy assessed through RMSE (0.60–3.64%). The SMAP surface (0–5 cm) dataset yielded a lower RMSE of 0.60–2.08%, aligning with its higher correlation. This study underlines the critical role of soil moisture in comprehensive fire risk assessments and highlights the necessity of incorporating modeled soil moisture data in fire management strategies, particularly in regions lacking comprehensive in situ monitoring. Full article

(This article belongs to the Special Issue Machine Learning (ML) and Deep Learning (DL) Applications in Wildfire Science: Principles, Progress and Prospects)

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16 pages, 1224 KiB

Open AccessArticle

Characteristics of Pyrolysis Products of California Chaparral and Their Potential Effect on Wildland Fires

by Mahsa Alizadeh, David R. Weise and Thomas H. Fletcher

Fire 2024, 7(8), 271; https://doi.org/10.3390/fire7080271 - 5 Aug 2024

Viewed by 1111

Abstract

The aim of this study was to investigate the pyrolysis of selected California foliage and estimate the energy content of the released volatiles to show the significance of the pyrolysis of foliage and its role during wildland fires. While the majority of the [...] Read more.

The aim of this study was to investigate the pyrolysis of selected California foliage and estimate the energy content of the released volatiles to show the significance of the pyrolysis of foliage and its role during wildland fires. While the majority of the volatiles released during the pyrolysis of foliage later combust and promote fire propagation, studies on the energy released from combustion of these compounds are scarce. Samples of chamise (Adenostoma fasciculatum), Eastwood’s manzanita (Arctostaphylos glandulosa), scrub oak (Quercus berberidifolia), hoaryleaf ceanothus (Ceanothus crassifolius), all native to southern California, and sparkleberry (Vaccinium arboreum), native to the southern U.S., were pyrolyzed at 725 °C with a heating rate of approximately 180 °C/s to mimic the conditions of wildland fires. Tar and light gases were collected and analyzed. Tar from chamise, scrub oak, ceanothus and sparkleberry was abundant in aromatics, especially phenol, while tar from manzanita was mainly composed of cycloalkenes. The four major components of light gases were CO, CO₂, CH₄ and H₂. Estimated values for the high heating values (HHVs) of volatiles ranged between 18.9 and 23.2 (MJ/kg of biomass) with tar contributing to over 80% of the HHVs of the volatiles. Therefore, fire studies should consider the heat released from volatiles present in both tar and light gases during pyrolysis. Full article

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19 pages, 10282 KiB

Open AccessArticle

The Influence of the Fire Point on the Thermal Dynamic Disaster in the Goaf

by Xiaokun Chen, Chao Song and Zhipeng Zhang

Fire 2024, 7(8), 270; https://doi.org/10.3390/fire7080270 - 4 Aug 2024

Viewed by 1146

Abstract

A thermal dynamic disaster in the goaf is one of the most serious coal mine disasters formed by coal spontaneous combustion and gas interweaving. However, the influence of the high-temperature hidden fire source formed in the goaf on the evolution law of thermal [...] Read more.

A thermal dynamic disaster in the goaf is one of the most serious coal mine disasters formed by coal spontaneous combustion and gas interweaving. However, the influence of the high-temperature hidden fire source formed in the goaf on the evolution law of thermal dynamic disasters is not clear, and effective prevention and control measures cannot be taken. Therefore, this paper uses the experimental platform of thermal dynamic disaster in the goaf to study the influence of different fire point positions on the development of thermal dynamic disaster in the goaf through a similar simulation experiment of thermal dynamic disaster evolution in the goaf and analyzes the corresponding relationship between temperature and CO concentration in the upper corner. The results show that under different locations of heat source, the high-temperature heat source of coal spontaneous combustion migrates to the air leakage side with sufficient oxygen supply, and an oxygen-poor circle is formed near the ignition point. Under the action of air leakage flow, CH₄ accumulates in the deep part of the goaf on the return air side. Due to the increase in coal, part of CH₄ is produced, which leads to the increase in concentration of CH₄ at the ignition point. Under the action of different heat sources, the changing trend of concentration of CO and temperature in the return air corner is the same, but the temperature change in the return air corner shows a lag compared with the change in the concentration of CO, so concentration monitoring of CO can reflect the evolution process of the fire field in the goaf more quickly than temperature monitoring. Full article

(This article belongs to the Special Issue Prevention and Control of Mine Fire)

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22 pages, 6692 KiB

Open AccessArticle

Thermal Characteristics of Multiple Blockages with Various Sizes in Longitudinal Ventilated Tunnel Fire

by Herui Zhang, Fengqiang Dai, Bin Miao, Zhengfei Wu and Jianchun Ou

Fire 2024, 7(8), 269; https://doi.org/10.3390/fire7080269 - 2 Aug 2024

Viewed by 1098

Abstract

In longitudinal ventilation tunnel fires, the thermal characteristics become more intricate due to the presence of blockages. This phenomenon becomes more complex when multiple blockages occur, which results in a unique interaction between the fire and longitudinal ventilation through gaps between the blockages. [...] Read more.

In longitudinal ventilation tunnel fires, the thermal characteristics become more intricate due to the presence of blockages. This phenomenon becomes more complex when multiple blockages occur, which results in a unique interaction between the fire and longitudinal ventilation through gaps between the blockages. Most of the previous studies have only considered single obstacles or have only performed qualitative analyses and have not obtained predictive models. To fill this research gap, we conducted numerical simulations using the Fire Dynamic Simulator (FDS) to study the effects of vehicular blockages in three lanes and two fire locations. Our study highlights the differences in the flame behavior, maximum temperature rise, and smoke back-layering length in the presence of multiple blockages and reveals that as the ventilation velocity increases, the flame bifurcation angle increases and the smoke back-layering length decreases. Additionally, when the fire is in the side lane, the flame tilts towards the sidewall, leading to higher maximum temperatures compared to those in the middle lane. Based on these findings, we have developed modified formulas that predict the maximum temperature rise, smoke back-layering length, and maximum temperature ratio at different fire locations and blockage rates, which are linearly related. Full article

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29 pages, 10907 KiB

Open AccessReview

The Progress of Autoignition of High-Pressure Hydrogen Gas Leakage: A Comprehensive Review

by Gan Cui, Yixuan Li, Di Wu, Hongwei Li, Huan Liu, Xiao Xing and Jianguo Liu

Fire 2024, 7(8), 268; https://doi.org/10.3390/fire7080268 - 2 Aug 2024

Cited by 4 | Viewed by 3557

Abstract

As a paradigm of clean energy, hydrogen is gradually attracting global attention. However, its unique characteristics of leakage and autoignition pose significant challenges to the development of high-pressure hydrogen storage technologies. In recent years, numerous scholars have made significant progress in the field [...] Read more.

As a paradigm of clean energy, hydrogen is gradually attracting global attention. However, its unique characteristics of leakage and autoignition pose significant challenges to the development of high-pressure hydrogen storage technologies. In recent years, numerous scholars have made significant progress in the field of high-pressure hydrogen leakage autoignition. This paper, based on diffusion ignition theory, thoroughly explores the mechanism of high-pressure hydrogen leakage autoignition. It reviews the effects of various factors such as gas properties, burst disc rupture conditions, tube geometric structure, obstacles, etc., on shock wave growth patterns and autoignition characteristics. Additionally, the development of internal flames and propagation characteristics of external flames after ignition kernels generation are summarized. Finally, to promote future development in the field of high-pressure hydrogen energy storage and transportation, this paper identifies deficiencies in the current research and proposes key directions for future research. Full article

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15 pages, 8032 KiB

Open AccessArticle

Impacts and Drivers of Summer Wildfires in the Cape Peninsula: A Remote Sensing Approach

by Kanya Xongo, Nasiphi Ngcoliso and Lerato Shikwambana

Fire 2024, 7(8), 267; https://doi.org/10.3390/fire7080267 - 1 Aug 2024

Viewed by 1881

Abstract

Over the years, the Cape Peninsula has seen a rise in the number of fires that occur seasonally. This study aimed to investigate the extent of fire spread and associated damages during the 2023/2024 Cape Peninsula fire events. Remote sensing datasets from Sentinel-5P, [...] Read more.

Over the years, the Cape Peninsula has seen a rise in the number of fires that occur seasonally. This study aimed to investigate the extent of fire spread and associated damages during the 2023/2024 Cape Peninsula fire events. Remote sensing datasets from Sentinel-5P, Sentinel-2, Moderate Resolution Imaging Spectroradiometer (MODIS), and Modern-Era Retrospective analysis for Research and Applications, Version 2 (MERRA-2) were used. Most of the fires on the northern side of the Cape Peninsula had a short burning span of between 6 and 12 h, but fires with a duration of 12–24 h were minimal. The northern area is composed of low forests and thickets as well as fynbos species, which were the primary fuel sources. Excessive amounts of carbon monoxide (CO) and black carbon (BC) emissions were observed. High speeds were observed during the period of the fires. This is one of the factors that led to the spread of the fire. Relative humidity at 60% was observed, indicating slightly dry conditions. Additionally, the Leaf Water Content Index (LWCI) indicated drier vegetation, enhancing fire susceptibility. High temperatures, low moisture and strong winds were the main drivers of the fire. The Normalized Burn Ratio (NBR) values for the targeted fires showed values close to −1, which signifies presence of a fire scar. The study can be of use to those in the fire management agencies and biodiversity conservation in the region. Full article

(This article belongs to the Special Issue Biomass-Burning)

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18 pages, 2698 KiB

Open AccessReview

Current Status and Prospects of Plant Flammability Measurements

by Minting Jian, Yi Jian, Hong Zeng, Dongyu Cao and Xinglei Cui

Fire 2024, 7(8), 266; https://doi.org/10.3390/fire7080266 - 1 Aug 2024

Cited by 2 | Viewed by 2225

Abstract

In recent years, the frequency of wildfires worldwide has been gradually increasing, posing significant threats to global ecosystems and human society. Given that plants serve as the primary fuel in natural environments, accurately assessing the flammability of plants is crucial for wildfire management [...] Read more.

In recent years, the frequency of wildfires worldwide has been gradually increasing, posing significant threats to global ecosystems and human society. Given that plants serve as the primary fuel in natural environments, accurately assessing the flammability of plants is crucial for wildfire management and fire ecology studies. Plant flammability is a multifaceted trait influenced by various physiological, physical, and chemical characteristics of plants. Currently, there is no universally accepted standard for quantifying plant flammability. By analyzing published research over the past few decades, this study found that 17.27% of studies assessed plant flammability by measuring flammability-related characteristics, such as moisture content, leaf size, bark thickness, oil content, and terpene content; a total of 34.55% of studies assessed plant flammability through burning experiments by measuring burning parameters, such as ignition time, duration of combustion, and flame spread rate. The remaining studies, approximately 50%, used a combination of burning experiments and flammability-related characteristic measurement to assess plant flammability. This study outlined the current status of plant flammability measurements, discussed the merits of each measurement method, and proposed suggestions for enhancing the assessment of plant flammability, with the aim of contributing to the standardization of plant flammability measurements. Full article

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Fire, Volume 7, Issue 8 (August 2024) – 34 articles

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