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Fire, Volume 4, Issue 4 (December 2021) – 19 articles

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Article
Georeferencing Oblique Aerial Wildfire Photographs: An Untapped Source of Fire Behaviour Data
Fire 2021, 4(4), 81; https://doi.org/10.3390/fire4040081 (registering DOI) - 22 Oct 2021
Viewed by 170
Abstract
In this study, we investigate a novel application of the photogrammetric monoplotting technique for assessing wildfires. We demonstrate the use of the software program WSL Monoplotting Tool (MPT) to georeference operational oblique aerial wildfire photographs taken during airtanker response in the early stages [...] Read more.
In this study, we investigate a novel application of the photogrammetric monoplotting technique for assessing wildfires. We demonstrate the use of the software program WSL Monoplotting Tool (MPT) to georeference operational oblique aerial wildfire photographs taken during airtanker response in the early stages of fire growth. We located the position of the fire front in georeferenced pairs of photos from five fires taken 31–118 min apart, and calculated the head fire spread distance and head fire rate of spread (HROS). Our example photos were taken 0.7 to 4.7 km from fire fronts, with camera angles of incidence from −19 to −50° to image centre. Using high quality images with detailed landscape features, it is possible to identify fire front positions with high precision; in our example data, the mean 3D error was 0.533 m and the maximum 3D error for individual fire runs was less than 3 m. This resulted in a maximum HROS error due to monoplotting of only ~0.5%. We then compared HROS estimates with predictions from the Canadian Fire Behavior Prediction System, with differences mainly attributed to model error or uncertainty in weather and fuel inputs. This method can be used to obtain observations to validate fire spread models or create new empirical relationships where databases of such wildfire photos exist. Our initial work suggests that monophotogrammetry can provide reproducible estimates of fire front position, spread distance and rate of spread with high accuracy, and could potentially be used to characterize other fire features such as flame and smoke plume dimensions and spotting. Full article
(This article belongs to the Section Fire Science Models, Remote Sensing, and Data)
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Article
Environmental Influences on Density and Height Growth of Natural Ponderosa Pine Regeneration following Wildfires
Fire 2021, 4(4), 80; https://doi.org/10.3390/fire4040080 - 21 Oct 2021
Viewed by 191
Abstract
Over the past century the size and severity of wildfires, as well as post-fire recovery processes (e.g., seedling establishment), have been altered from historical levels due to management policies and changing climate. Tree seedling establishment and growth drive future overstory tree dynamics after [...] Read more.
Over the past century the size and severity of wildfires, as well as post-fire recovery processes (e.g., seedling establishment), have been altered from historical levels due to management policies and changing climate. Tree seedling establishment and growth drive future overstory tree dynamics after wildfire. Post-fire tree regeneration can be highly variable depending on burn severity, pre-fire forest condition, tree regeneration strategies, and climate; however, few studies have examined how different abiotic and biotic factors impact seedling density and growth and the interactions among those factors. We measured seedling density and height growth in the period 2015–2016 on three wildfires that burned in ponderosa pine (Pinus ponderosa) forests in the period 2000–2007 across broad environmental and burn severity gradients. Using a non-parametric multiplicative regression model, we found that downed woody fuel load, duff depth, and fall precipitation best explained variation in seedling density, while the distance to nearest seed tree, a soil productivity index, duff depth, and spring precipitation as snow best explained seedling height growth. Overall, results highlight the importance of burn severity and post-fire climate in tree regeneration, although the primary factors influencing seedling density and height growth vary. Drier conditions and changes to precipitation seasonality have the potential to influence tree establishment, survival, and growth in post-fire environments, which could lead to significant impacts for long-term forest recovery. Full article
(This article belongs to the Special Issue Effects of Wildfire on Biodiversity)
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Article
Tree-Ring Based Reconstruction of Historical Fire in an Endangered Ecosystem in the Florida Keys
Fire 2021, 4(4), 79; https://doi.org/10.3390/fire4040079 - 21 Oct 2021
Viewed by 321
Abstract
Big Pine Key, Florida, is home to one of Earth’s largest swaths of the critically-endangered dry forests. Known as pine rocklands, this fire-adapted ecosystem must experience regular fire to persist and remain healthy. Pine rocklands are composed of a sole canopy species: the [...] Read more.
Big Pine Key, Florida, is home to one of Earth’s largest swaths of the critically-endangered dry forests. Known as pine rocklands, this fire-adapted ecosystem must experience regular fire to persist and remain healthy. Pine rocklands are composed of a sole canopy species: the South Florida slash pine (Pinus elliottii var. densa), along with a dense understory of various woody and herbaceous species, and minimal surface moisture and soil development. Slash pine record wildfire activity of the surrounding area via fire scars preserved within the annual tree rings formed by the species. Our study used dendrochronology to investigate the fire history of the pine rocklands on Big Pine Key, specifically within and around the National Key Deer Refuge (NKDR) because it is the largest segment of unfragmented pine rockland on the island. We combined the results found within the NKDR with those of a previous study completed in 2011, and incorporated historical documents and reports of prescribed and natural fires through November 2019 into our evaluation of fire history on Big Pine Key. We conclude that prescribed burning practices are vital to truly restore natural fire behavior, and repeated burning on these islands in the future must be prioritized. Full article
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Article
Mixed-Severity Wildfire as a Driver of Vegetation Change in an Arizona Madrean Sky Island System, USA
Fire 2021, 4(4), 78; https://doi.org/10.3390/fire4040078 (registering DOI) - 20 Oct 2021
Viewed by 215
Abstract
Fire is a powerful natural disturbance influencing vegetation patterns across landscapes. Recent transitions from mixed-species forests to post-fire shrublands after severe wildfire is an increasingly prevalent phenomenon in pine-oak and conifer forest ecosystems in southwestern North America. However, we know little about how [...] Read more.
Fire is a powerful natural disturbance influencing vegetation patterns across landscapes. Recent transitions from mixed-species forests to post-fire shrublands after severe wildfire is an increasingly prevalent phenomenon in pine-oak and conifer forest ecosystems in southwestern North America. However, we know little about how variation in fire severity influences other common forest types in the region. In this study, we evaluated fire-induced changes in woody plant community composition and forest structure in Chiricahua Mountains in southeastern Arizona in the United States that hosts a diverse set of vegetation types. Cluster analysis of the pre-fire vegetation data identified three dominant pre-fire vegetation types including juniper woodland, piñon forest, and pine-oak forest. All vegetation types experienced significant tree mortality across a wide range of size classes and species, from forests to shrublands. The magnitude of change within sample plots varied with fire severity, which was mediated by topography. Significant shifts in dominance away from coniferous obligate seeder trees to resprouting hardwoods and other shrubs occurred across all vegetation types in response to the fire. Regeneration from seed can be episodic, but projected increases in aridity and fire frequency may promote continued dominance by hardwoods and fire- and drought-resistant shrub communities, which is a regional forest management concern as wildfire size and severity continue to increase throughout the southwestern USA. Full article
(This article belongs to the Special Issue Effects of Wildfire on Biodiversity)
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Concept Paper
Increasing Pace and Scale of Prescribed Fire via Catastrophe Funds for Liability Relief
Fire 2021, 4(4), 77; https://doi.org/10.3390/fire4040077 - 19 Oct 2021
Viewed by 143
Abstract
Increased prescribed burning is needed to provide a diversity of public benefits, including wildfire hazard reduction, improved forest resilience, and biodiversity conservation. Though rare, escaped burns or significant smoke impacts may result in harm to individuals and property. Liability for potential damages reduces [...] Read more.
Increased prescribed burning is needed to provide a diversity of public benefits, including wildfire hazard reduction, improved forest resilience, and biodiversity conservation. Though rare, escaped burns or significant smoke impacts may result in harm to individuals and property. Liability for potential damages reduces the willingness of fire managers to expand the practice, particularly where the wildland–urban interface creates the greatest risk. Across the United States of America, efforts have been made to reduce prescribed fire-related risks through statutory reform, training and certification requirements, and private insurance. An increasing number of states have adopted the liability standard of gross negligence to protect prescribed fire practitioners. When liability relief is tied to best practices or burn manager certification, risk to the public from potential prescribed fire impacts is reduced. Under this model, however, those harmed by prescribed fire may have little legal recourse for compensation from losses. Here, we explore the pairing of a mechanism to compensate losses while limiting liability for practitioners who use best management practices. Specifically, we assess the suitability of using a catastrophe fund in conjunction with adoption of gross negligence standards, modeled after other natural hazards examples. This model could ensure public support and sustain and expand prescribed fire in many fire-prone landscapes. Full article
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Article
Vegetation Recovery Patterns in Burned Areas Assessed with Landsat 8 OLI Imagery and Environmental Biophysical Data
Fire 2021, 4(4), 76; https://doi.org/10.3390/fire4040076 (registering DOI) - 18 Oct 2021
Viewed by 278
Abstract
Vegetation recovery after the large wildfires that occurred in central Portugal in 2017 is assessed in the present study. These wildfires had catastrophic consequences, among which were human losses and a vast extent of forest devastation. Landsat 8 OLI images were used to [...] Read more.
Vegetation recovery after the large wildfires that occurred in central Portugal in 2017 is assessed in the present study. These wildfires had catastrophic consequences, among which were human losses and a vast extent of forest devastation. Landsat 8 OLI images were used to obtain the land use and cover (LUC) classification and to determine the Normalized Burned Ratio index (NBR) for different times. NBR results were used to determine the difference between the NBR (dNBR) before the fire (pre-fire) and after the fire (post-fire), and the results obtained were cross-checked with the LUC. The dNBR results were cross-referenced with biophysical data to identify the characteristics of the most important burned areas in need of vegetative recovery. The results showed the spatial differentiation in vegetation recovery, highlighting different factors in this process, in particular the type of vegetation (the predominant species and bank of seeds available), the biophysical characteristics of burned areas (for example, the soil type in burned areas), the continentality gradient, and the climate conditions. The vegetation recovery was differentiated by time according to the species present in the burned areas pre-fire. In general, shrubland recovery was faster than that of tree species, and the recovery was more marked for species that were regenerated by the rhizomes after fire. The recovery process was also influenced by the season in the study area. It was more efficient in the spring and at the beginning of the summer, highlighting the importance of optimal conditions needed for vegetation regeneration, such as the temperature and precipitation (soil humidity and water availability for growing plants). The results of this research are important to forest planning: the definition of the strategies for the ecosystems’ recovery, the adoption of preventive measures to avoid the occurrence of large wildfires, the modification of anthropogenic practices, etc. Full article
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Article
A Deep Learning Based Object Identification System for Forest Fire Detection
Fire 2021, 4(4), 75; https://doi.org/10.3390/fire4040075 - 17 Oct 2021
Viewed by 346
Abstract
Forest fires are still a large concern in several countries due to the social, environmental and economic damages caused. This paper aims to show the design and validation of a proposed system for the classification of smoke columns with object detection and a [...] Read more.
Forest fires are still a large concern in several countries due to the social, environmental and economic damages caused. This paper aims to show the design and validation of a proposed system for the classification of smoke columns with object detection and a deep learning-based approach. This approach is able to detect smoke columns visible below or above the horizon. During the dataset labelling, the smoke object was divided into three different classes, depending on its distance to the horizon, a cloud object was also added, along with images without annotations. A comparison between the use of RetinaNet and Faster R-CNN was also performed. Using an independent test set, an F1-score around 80%, a G-mean around 80% and a detection rate around 90% were achieved by the two best models: both were trained with the dataset labelled with three different smoke classes and with augmentation; Faster R-CNNN was the model architecture, re-trained during the same iterations but following different learning rate schedules. Finally, these models were tested in 24 smoke sequences of the public HPWREN dataset, with 6.3 min as the average time elapsed from the start of the fire compared to the first detection of a smoke column. Full article
(This article belongs to the Section Fire Science Models, Remote Sensing, and Data)
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Article
Analysis of Trends in the FireCCI Global Long Term Burned Area Product (1982–2018)
Fire 2021, 4(4), 74; https://doi.org/10.3390/fire4040074 - 17 Oct 2021
Viewed by 168
Abstract
We present an analysis of the spatio-temporal trends derived from long-term burned area (BA) data series. Two global BA products were included in our analysis, the FireCCI51 (2001–2019) and the FireCCILT11 (1982–2018) datasets. The former was generated from Moderate Resolution Imaging Spectroradiometer (MODIS) [...] Read more.
We present an analysis of the spatio-temporal trends derived from long-term burned area (BA) data series. Two global BA products were included in our analysis, the FireCCI51 (2001–2019) and the FireCCILT11 (1982–2018) datasets. The former was generated from Moderate Resolution Imaging Spectroradiometer (MODIS) 250 m reflectance data, guided by 1 km active fires. The FireCCILT11 dataset was generated from Land Long-Term Data Record data (0.05°), which provides a consistent time series for Advanced Very High Resolution Radiometer images, acquired from the NOAA satellite series. FireCCILT11 is the longest time series of a BA product currently available, making it possible to carry out temporal analysis of long-term trends. Both products were developed under the FireCCI project of the European Space Agency. The two datasets were pre-processed to correct for temporal autocorrelation. Unburnable areas were removed and the lack of the FireCCILT11 data in 1994 was examined to evaluate the impact of this gap on the BA trends. An analysis and comparison between the two BA products was performed using a contextual approach. Results of the contextual Mann-Kendall analysis identified significant trends in both datasets, with very different regional values. The long-term series presented larger clusters than the short-term ones. Africa displayed significant decreasing trends in the short-term, and increasing trends in the long-term data series, except in the east. In the long-term series, Eastern Africa, boreal regions, Central Asia and South Australia showed large BA decrease clusters, and Western and Central Africa, South America, USA and North Australia presented BA increase clusters. Full article
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Article
Nonlinear Analysis of a Steel Frame Structure Exposed to Post-Earthquake Fire
Fire 2021, 4(4), 73; https://doi.org/10.3390/fire4040073 - 15 Oct 2021
Viewed by 72
Abstract
The probability of extreme events such as an earthquake, fire or blast occurring during the lifetime of a structure is relatively low but these events can cause serious damage to the structure as well as to human life. Due to the significant consequences [...] Read more.
The probability of extreme events such as an earthquake, fire or blast occurring during the lifetime of a structure is relatively low but these events can cause serious damage to the structure as well as to human life. Due to the significant consequences for occupant and structural safety, an accurate analysis of the response of structures exposed to these events is required for their design. Some extreme events may occur as a consequence of another hazard, for example, a fire may occur due to the failure of the electrical system of a structure following an earthquake. In such circumstances, the structure is subjected to a multi-hazard loading scenario. A post-earthquake fire (PEF) is one of the major multi-hazard events that is reasonably likely to occur but has been the subject of relatively little research in the available literature. In most international design codes, structures exposed to multi-hazards scenarios such as earthquakes, which are then followed by fires are only analysed and designed for as separate events, even though structures subjected to an earthquake may experience partial damage resulting in a more severe response to a subsequent fire. Most available analysis procedures and design codes do not address the association of the two hazards. Thus, the design of structures based on existing standards may contribute to a significant risk of structural failure. Indeed, a suitable method of analysis is required to investigate the behaviour of structures when exposed to sequential hazards. In this paper, a multi-hazard analysis approach is developed, which considers the damage caused to structures during and after an earthquake through a subsequent thermal analysis. A methodology is developed and employed to study the nonlinear behaviour of a steel framed structure under post-earthquake fire conditions. A three-dimensional nonlinear finite element model of an unprotected steel frame is developed and outlined. Full article
(This article belongs to the Special Issue Performance-Based Design in Structural Fire Engineering)
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Article
Reconstruction of the Spring Hill Wildfire and Exploration of Alternate Management Scenarios Using QUIC-Fire
Fire 2021, 4(4), 72; https://doi.org/10.3390/fire4040072 - 15 Oct 2021
Viewed by 126
Abstract
New physics-based fire behavior models are poised to revolutionize wildland fire planning and training; however, model testing against field conditions remains limited. We tested the ability of QUIC-Fire, a fast-running and computationally inexpensive physics-based fire behavior model to numerically reconstruct a large wildfire [...] Read more.
New physics-based fire behavior models are poised to revolutionize wildland fire planning and training; however, model testing against field conditions remains limited. We tested the ability of QUIC-Fire, a fast-running and computationally inexpensive physics-based fire behavior model to numerically reconstruct a large wildfire that burned in a fire-excluded area within the New York–Philadelphia metropolitan area in 2019. We then used QUIC-Fire as a tool to explore how alternate hypothetical management scenarios, such as prescribed burning, could have affected fire behavior. The results of our reconstruction provide a strong demonstration of how QUIC-Fire can be used to simulate actual wildfire scenarios with the integration of local weather and fuel information, as well as to efficiently explore how fire management can influence fire behavior in specific burn units. Our results illustrate how both reductions of fuel load and specific modification of fuel structure associated with frequent prescribed fire are critical to reducing fire intensity and size. We discuss how simulations such as this can be important in planning and training tools for wildland firefighters, and for avenues of future research and fuel monitoring that can accelerate the incorporation of models like QUIC-Fire into fire management strategies. Full article
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Review
Probability Analysis and Prevention of Offshore Oil and Gas Accidents: Fire as a Cause and a Consequence
Fire 2021, 4(4), 71; https://doi.org/10.3390/fire4040071 - 14 Oct 2021
Viewed by 158
Abstract
Failures during the drilling and exploitation of hydrocarbons that result in catastrophic offshore oil and gas accidents are relatively rare but if they occur the consequences can be catastrophic in terms of loss of life and environmental damage. Therefore, to gain insight into [...] Read more.
Failures during the drilling and exploitation of hydrocarbons that result in catastrophic offshore oil and gas accidents are relatively rare but if they occur the consequences can be catastrophic in terms of loss of life and environmental damage. Therefore, to gain insight into their prevention, the largest major offshore oil and gas accidents, those with more than 10 fatalities or with a large environmental impact, are analyzed in this article. Special attention is placed on fire as a cause and a consequence. Relevant technological and legislative changes and updates regarding safety that have followed such accidents and that can prevent potential future similar misfortunes are evaluated. Two main approaches to safety are compared: (1) the American prescriptive vs. (2) the European goal-oriented approach. The main causes of accidents are tested statistically in respect of failure probability, where the exact confidence limits for the estimated probabilities are computed. The results of the statistical test based on exact confidence intervals show that there is no significant difference between the analysed factors, which describe the main causes of offshore oil and gas accidents. Based on the small but carefully chosen group of 24 of the largest accidents, it can be concluded that there is no evidence of a difference between the categories of the main causes of accidents. Full article
(This article belongs to the Special Issue Advances in Fire and Combustion Safety)
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Article
Numerical Analysis of Seismic Performances of Post-Fire Scoria Aggregate Concrete Beam-Column Joints
Fire 2021, 4(4), 70; https://doi.org/10.3390/fire4040070 - 14 Oct 2021
Viewed by 168
Abstract
In order to analyze the post-fire seismic performances of scoria aggregate concrete (SAC) beam-column joints precisely and effectively, one finite element model (FEM) was developed to simulate the seismic behavior of SAC beam-column joints. The FEM consists of two sequential parts: firstly, the [...] Read more.
In order to analyze the post-fire seismic performances of scoria aggregate concrete (SAC) beam-column joints precisely and effectively, one finite element model (FEM) was developed to simulate the seismic behavior of SAC beam-column joints. The FEM consists of two sequential parts: firstly, the heat transfer analysis of the beam-column joints, and then the seismic analysis of the SAC joints by combining the temperature field distribution obtained from the heat transfer analysis with the mechanical properties of the SAC after fire, both of which were implemented in ABAQUS. In order to make the simulation results more accurate, spring elements were applied to simulate the bond–slip behavior with material degradation due to fire damage in the simulation of seismic analysis. Moreover, in order to validate the FEM, the seismic behavior of the natural aggregate concrete (NAC) beam-column joints after fire was simulated with the established FEM, and the simulation results were compared with the available test data. It is proved that the FEM we built was accurate and effective and provided efficient solutions for evaluating the seismic performance of post-fire beam-column joints so that the effects of various parameters, namely, fire time, longitudinal reinforcement ratio, and axial compression ratio on the seismic performance of SAC beam-column joints after fire were investigated in depth, which indicated the increase of axial compression ratio can improve the strength, initial stiffness, and energy dissipation capacity of SAC joints, while the increase of longitudinal reinforcement ratio can increase the strength and stiffness of SAC joints to a small extent, but too high reinforcement ratio will significantly weaken the energy dissipation capacity of SAC joints. Full article
(This article belongs to the Collection Technical Forum for Fire Science Laboratory and Field Methods)
Article
Fine-Scale Fire Spread in Pine Straw
Fire 2021, 4(4), 69; https://doi.org/10.3390/fire4040069 - 10 Oct 2021
Viewed by 322
Abstract
Most wildland and prescribed fire spread occurs through ground fuels, and the rate of spread (RoS) in such environments is often summarized with empirical models that assume uniform environmental conditions and produce a unique RoS. On the other hand, representing the effects of [...] Read more.
Most wildland and prescribed fire spread occurs through ground fuels, and the rate of spread (RoS) in such environments is often summarized with empirical models that assume uniform environmental conditions and produce a unique RoS. On the other hand, representing the effects of local, small-scale variations of fuel and wind experienced in the field is challenging and, for landscape-scale models, impractical. Moreover, the level of uncertainty associated with characterizing RoS and flame dynamics in the presence of turbulent flow demonstrates the need for further understanding of fire dynamics at small scales in realistic settings. This work describes adapted computer vision techniques used to form fine-scale measurements of the spatially and temporally varying RoS in a natural setting. These algorithms are applied to infrared and visible images of a small-scale prescribed burn of a quasi-homogeneous pine needle bed under stationary wind conditions. A large number of distinct fire front displacements are then used statistically to analyze the fire spread. We find that the fine-scale forward RoS is characterized by an exponential distribution, suggesting a model for fire spread as a random process at this scale. Full article
Article
Evaluating the Persistence of Post-Wildfire Ash: A Multi-Platform Spatiotemporal Analysis
Fire 2021, 4(4), 68; https://doi.org/10.3390/fire4040068 - 09 Oct 2021
Viewed by 287
Abstract
As wildland fires amplify in size in many regions in the western USA, land and water managers are increasingly concerned about the deleterious effects on drinking water supplies. Consequences of severe wildfires include disturbed soils and areas of thick ash cover, which raises [...] Read more.
As wildland fires amplify in size in many regions in the western USA, land and water managers are increasingly concerned about the deleterious effects on drinking water supplies. Consequences of severe wildfires include disturbed soils and areas of thick ash cover, which raises the concern of the risk of water contamination via ash. The persistence of ash cover and depth were monitored for up to 90 days post-fire at nearly 100 plots distributed between two wildfires in Idaho and Washington, USA. Our goal was to determine the most ‘cost’ effective, operational method of mapping post-wildfire ash cover in terms of financial, data volume, time, and processing costs. Field measurements were coupled with multi-platform satellite and aerial imagery collected during the same time span. The image types spanned the spatial resolution of 30 m to sub-meter (Landsat-8, Sentinel-2, WorldView-2, and a drone), while the spectral resolution spanned visible through SWIR (short-wave infrared) bands, and they were all collected at various time scales. We that found several common vegetation and post-fire spectral indices were correlated with ash cover (r = 0.6–0.85); however, the blue normalized difference vegetation index (BNDVI) with monthly Sentinel-2 imagery was especially well-suited for monitoring the change in ash cover during its ephemeral period. A map of the ash cover can be used to estimate the ash load, which can then be used as an input into a hydrologic model predicting ash transport and fate, helping to ultimately improve our ability to predict impacts on downstream water resources. Full article
(This article belongs to the Special Issue Advances in the Assessment of Fire Impacts on Hydrology)
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Article
BIM-Based Co-Simulation of Fire and Occupants’ Behavior for Safe Construction Rehabilitation Planning
Fire 2021, 4(4), 67; https://doi.org/10.3390/fire4040067 - 04 Oct 2021
Viewed by 291
Abstract
Construction renovation projects increase the risk of structural fire, mostly due to the accumulation of combustible construction materials and waste. In particular, when the building remains operational during such projects, the redistribution of occupants and interruptions with access corridors/exit egress can exponentially increase [...] Read more.
Construction renovation projects increase the risk of structural fire, mostly due to the accumulation of combustible construction materials and waste. In particular, when the building remains operational during such projects, the redistribution of occupants and interruptions with access corridors/exit egress can exponentially increase the risk for the occupants. Most construction projects are, however, planned and scheduled merely based on the time and budget criteria. While safety is considered paramount and is meant to be applied as a hard constraint in the scheduling stage, in practice, safe evacuation considerations are reduced to rules of thumb and general code guidelines. In this paper, we propose simulation as a tool to introduce safety under structural fire, as a decision criterion, to be mixed with time and budget for selecting the best construction schedule alternative. We have used the BIM (building information model) to extract the building’s spatial and physical properties; and have applied co-simulation of fire, through computational fluid dynamics (CFD), and occupants’ evacuation behavior, through agent-based modeling (ABM) to estimate the average and maximum required safe egress time for various construction sequencing alternatives. This parameter is then used as a third decision criterion, combined with the project’s cost and duration, to evaluate construction schedule alternatives. We applied our method to a three-floor fire zone in a high-rise educational building in Montreal, and our results show that considering the fire safety criterion can make a difference in the final construction schedule. Our proposed method suggests an additional metric for evaluating renovation projects’ construction plans, particularly in congested buildings which need to remain fully or partially operational during the renovation. Thus, this method can be employed by safety officers and facility managers, as well as construction project planners to guide accounting for fire incidents while planning for these types of projects. Full article
Article
Spatial–Temporal Attention Two-Stream Convolution Neural Network for Smoke Region Detection
Fire 2021, 4(4), 66; https://doi.org/10.3390/fire4040066 - 03 Oct 2021
Viewed by 358
Abstract
Smoke detection is of great significance for fire location and fire behavior analysis in a fire video surveillance system. Smoke image classification methods based on a deep convolution network have achieved high accuracy. However, the combustion of different types of fuel can produce [...] Read more.
Smoke detection is of great significance for fire location and fire behavior analysis in a fire video surveillance system. Smoke image classification methods based on a deep convolution network have achieved high accuracy. However, the combustion of different types of fuel can produce smoke with different colors, such as black smoke, grey smoke, and white smoke. Additionally, the diffusion characteristic of smoke can lead to transparent smoke regions accompanied by colors and textures of background objects. Therefore, compared with smoke image classification, smoke region detection is a challenging task. This paper proposes a two-stream convolutional neural network based on spatio-temporal attention mechanism for smoke region segmentation (STCNNsmoke). The spatial stream extracts spatial features of foreground objects using the semi-supervised ranking model. The temporal stream uses optical flow characteristics to represent the dynamic characteristics of smoke such as diffusion and flutter features. Specifically, the spatio-temporal attention mechanism is presented to fuse the spatial and temporal characteristics of smoke and pay more attention to the moving regions with smoke colors and textures by predicting attention weights of channels. Furthermore, the spatio-temporal attention model improves the channel response of smoke-moving regions for the segmentation of complete smoke regions. The proposed method is evaluated and analyzed from multiple perspectives such as region detection accuracy and anti-interference. The experimental results showed that the proposed method significantly improved the ability of segmenting thin smoke and small smoke. Full article
(This article belongs to the Section Fire Science Models, Remote Sensing, and Data)
Article
Estimation of Byram’s Fire Intensity and Rate of Spread from Spaceborne Remote Sensing Data in a Savanna Landscape
Fire 2021, 4(4), 65; https://doi.org/10.3390/fire4040065 - 29 Sep 2021
Viewed by 383
Abstract
Fire behavior is well described by a fire’s direction, rate of spread, and its energy release rate. Fire intensity as defined by Byram (1959) is the most commonly used term describing fire behavior in the wildfire community. It is, however, difficult to observe [...] Read more.
Fire behavior is well described by a fire’s direction, rate of spread, and its energy release rate. Fire intensity as defined by Byram (1959) is the most commonly used term describing fire behavior in the wildfire community. It is, however, difficult to observe from space. Here, we assess fire spread and fire radiative power using infrared sensors with different spatial, spectral and temporal resolutions. The sensors used offer either high spatial resolution (Sentinel-2) for fire detection, but a low temporal resolution, moderate spatial resolution and daily observations (VIIRS), and high temporal resolution with low spatial resolution and fire radiative power retrievals (Meteosat SEVIRI). We extracted fire fronts from Sentinel-2 (using the shortwave infrared bands) and use the available fire products for S-NPP VIIRS and Meteosat SEVIRI. Rate of spread was analyzed by measuring the displacement of fire fronts between the mid-morning Sentinel-2 overpasses and the early afternoon VIIRS overpasses. We retrieved FRP from 15-min Meteosat SEVIRI observations and estimated total fire radiative energy release over the observed fire fronts. This was then converted to total fuel consumption, and, by making use of Sentinel-2-derived burned area, to fuel consumption per unit area. Using rate of spread and fuel consumption per unit area, Byram’s fire intensity could be derived. We tested this approach on a small number of fires in a frequently burning West African savanna landscape. Comparison to field experiments in the area showed similar numbers between field observations and remote-sensing-derived estimates. To the authors’ knowledge, this is the first direct estimate of Byram’s fire intensity from spaceborne remote sensing data. Shortcomings of the presented approach, foundations of an error budget, and potential further development, also considering upcoming sensor systems, are discussed. Full article
(This article belongs to the Special Issue Fire in Savanna Landscapes)
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Technical Note
Loss and Recovery of Carbon in Repeatedly Burned Degraded Peatlands of Kalimantan, Indonesia
Fire 2021, 4(4), 64; https://doi.org/10.3390/fire4040064 - 28 Sep 2021
Viewed by 343
Abstract
Although accurate estimates of biomass loss during peat fires, and recovery over time, are critical in understanding net peat ecosystem carbon balance, empirical data to inform carbon models are scarce. During the 2019 dry season, fires burned through 133,631 ha of degraded peatlands [...] Read more.
Although accurate estimates of biomass loss during peat fires, and recovery over time, are critical in understanding net peat ecosystem carbon balance, empirical data to inform carbon models are scarce. During the 2019 dry season, fires burned through 133,631 ha of degraded peatlands of Central Kalimantan. This study reports carbon loss from surface fuels and the top peat layer of 18.5 Mg C ha−1 (3.5 from surface fuels and 15.0 from root/peat layer), releasing an average of 2.5 Gg (range 1.8–3.1 Gg) carbon in these fires. Peat surface change measurements over one month, as the fires continued to smolder, indicated that about 20 cm of the surface was lost to combustion of peat and fern rhizomes, roots and recently incorporated organic residues that we sampled as the top peat layer. Time series analysis of live green vegetation (NDVI trend), combined with field observations of vegetation recovery two years after the fires, indicated that vegetation recovery equivalent to fire-released carbon is likely to occur around 3 years after fires. Full article
Article
Quantifying the Prevalence and Practice of Suppression Firing with Operational Data from Large Fires in Victoria, Australia
Fire 2021, 4(4), 63; https://doi.org/10.3390/fire4040063 - 27 Sep 2021
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Abstract
Fire management agencies around the world use suppression firing for fire control. Yet, we know little about the extent of its use (e.g., prevalence and spatial coverage) and its impact on containment. We examine the prevalence and practice of suppression firing in Victoria, [...] Read more.
Fire management agencies around the world use suppression firing for fire control. Yet, we know little about the extent of its use (e.g., prevalence and spatial coverage) and its impact on containment. We examine the prevalence and practice of suppression firing in Victoria, Australia. We used operational data from five years (2010–2015) to identify and map the incidence of suppression firing on 74 large fires (500+ ha). Suppression firing occurred on half (34) of these fires, 26 of which had data to map firing locations. The area burnt by suppression firing ranged from <1 ha to ~20,000 ha on separate fires. Archetypal suppression firing occurred during intervals of low fire spread and resulted in modest fire behaviour. Ground crews generally conducted the perimeter suppression firing. Aerial ignition was more common on large internal firing operations. For the 26 fires where we mapped the firing locations, firing occurred along 77% of the perimeter-aligned road. Suppression firing was a prominent containment tool used along one-fifth of the total external perimeter of these 74 large fires. Quantification of this practice is a first step towards establishing ignition thresholds, production rates, and integration with containment probability models. Full article
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