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Статті в журналах з теми "Firebrand transport"

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Автор: Grafiati

Опубліковано: 10 грудня 2022

Оновлено: 28 січня 2023

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Wadhwani, R., D. Sutherland, A. Ooi, and K. Moinuddin. "<i>Corrigendum to</i>: Firebrand transport from a novel firebrand generator: numerical simulation of laboratory experiments." International Journal of Wildland Fire 31, no. 6 (June 24, 2022): 649. http://dx.doi.org/10.1071/wf21088_co.

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Firebrands (often called embers) increase the propagation rate of wildfires and often cause the ignition and destruction of houses. Predicting the motion of firebrands and the ignition of new fires is therefore of significant interest to fire authorities. Numerical models have the potential to accurately predict firebrand transport. The present study focuses on conducting a set of benchmark experiments using a novel firebrand generator, a device that produces controlled and repeatable sets of firebrands, and validating a numerical model for firebrand transport against this set of experiments. The validation is conducted for the transport of non-burning and burning cubiform firebrand particles at two flow speeds. Four generic drag sub-models used to estimate drag coefficients that are suited for a wide variety of firebrand shapes are verified for their applicability to firebrand transport modelling. The four sub-models are found to be good in various degrees at predicting the transport of firebrand particles.

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Koo, Eunmo, Patrick J. Pagni, David R. Weise, and John P. Woycheese. "Firebrands and spotting ignition in large-scale fires." International Journal of Wildland Fire 19, no. 7 (2010): 818. http://dx.doi.org/10.1071/wf07119.

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Spotting ignition by lofted firebrands is a significant mechanism of fire spread, as observed in many large-scale fires. The role of firebrands in fire propagation and the important parameters involved in spot fire development are studied. Historical large-scale fires, including wind-driven urban and wildland conflagrations and post-earthquake fires are given as examples. In addition, research on firebrand behaviour is reviewed. The phenomenon of spotting fires comprises three sequential mechanisms: generation, transport and ignition of recipient fuel. In order to understand these mechanisms, many experiments have been performed, such as measuring drag on firebrands, analysing the flow fields of flame and plume structures, collecting firebrands from burning materials, houses and wildfires, and observing firebrand burning characteristics in wind tunnels under the terminal velocity condition and ignition characteristics of fuel beds. The knowledge obtained from the experiments was used to develop firebrand models. Since Tarifa developed a firebrand model based on the terminal velocity approximation, many firebrand transport models have been developed to predict maximum spot fire distance. Combustion models of a firebrand were developed empirically and the maximum spot fire distance was found at the burnout limit. Recommendations for future research and development are provided.

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Koo, Eunmo, Rodman R. Linn, Patrick J. Pagni, and Carleton B. Edminster. "Modelling firebrand transport in wildfires using HIGRAD/FIRETEC." International Journal of Wildland Fire 21, no. 4 (2012): 396. http://dx.doi.org/10.1071/wf09146.

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Firebrand transport is studied for disc and cylindrical firebrands by modelling their trajectories with a coupled-physics fire model, HIGRAD/FIRETEC. Through HIGRAD/FIRETEC simulations, the size of possible firebrands and travelled distances are analysed to assess spot ignition hazard. Trajectories modelled with and without the assumption that the firebrands’ relative velocities always equal their terminal velocities are. Various models for the flight and combustion of disc- and cylindrical-shaped firebrands are evaluated. Eight simulations are performed with surface fuel fires and four simulations are performed with combined surface and canopy fuels. Firebrand trajectories without terminal velocity are larger than those from models with terminal velocity. Discs travel further than cylinders, as discs are aerodynamically more favourable. Thin discs burning on their faces and tall cylinders burning around their circumference have shorter lifetimes than thin discs burning from their circumference or longer cylinders burning from their ends. Firebrands from canopy fires, with larger size and potential to ignite recipient fuel, travel further than firebrands from surface fires. In the simulations, which included a line fire ignition in homogeneous fuels on flat terrain, the firebrand launching patterns are very heterogeneous, and the trajectories and landing patterns are dominated by the coupled fire–atmosphere behaviour.

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Wickramasinghe, Amila, Nazmul Khan, and Khalid Moinuddin. "Determining Firebrand Generation Rate Using Physics-Based Modelling from Experimental Studies through Inverse Analysis." Fire 5, no. 1 (January 8, 2022): 6. http://dx.doi.org/10.3390/fire5010006.

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Firebrand spotting is a potential threat to people and infrastructure, which is difficult to predict and becomes more significant when the size of a fire and intensity increases. To conduct realistic physics-based modeling with firebrand transport, the firebrand generation data such as numbers, size, and shape of the firebrands are needed. Broadly, the firebrand generation depends on atmospheric conditions, wind velocity and vegetation species. However, there is no experimental study that has considered all these factors although they are available separately in some experimental studies. Moreover, the experimental studies have firebrand collection data, not generation data. In this study, we have conducted a series of physics-based simulations on a trial-and-error basis to reproduce the experimental collection data, which is called an inverse analysis. Once the generation data was determined from the simulation, we applied the interpolation technique to calibrate the effects of wind velocity, relative humidity, and vegetation species. First, we simulated Douglas-fir (Pseudotsuga menziesii) tree-burning and quantified firebrand generation against the tree burning experiment conducted at the National Institute of Standards and Technology (NIST). Then, we applied the same technique to a prescribed forest fire experiment conducted in the Pinelands National Reserve (PNR) of New Jersey, the USA. The simulations were conducted with the experimental data of fuel load, humidity, temperature, and wind velocity to ensure that the field conditions are replicated in the experiments. The firebrand generation rate was found to be 3.22 pcs/MW/s (pcs-number of firebrands pieces) from the single tree burning and 4.18 pcs/MW/s in the forest fire model. This finding was complemented with the effects of wind, vegetation type, and fuel moisture content to quantify the firebrand generation rate.

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Thurston, William, Jeffrey D. Kepert, Kevin J. Tory, and Robert J. B. Fawcett. "The contribution of turbulent plume dynamics to long-range spotting." International Journal of Wildland Fire 26, no. 4 (2017): 317. http://dx.doi.org/10.1071/wf16142.

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Spotting can start fires up to tens of kilometres ahead of the primary fire front, causing rapid spread and placing immense pressure on suppression resources. Here, we investigate the dynamics of the buoyant plume generated by the fire and its ability to transport firebrands. We couple large-eddy simulations of bushfire plumes with a firebrand transport model to assess the effects of turbulent plume dynamics on firebrand trajectories. We show that plume dynamics have a marked effect on the maximum spotting distance and determine the amount of lateral and longitudinal spread in firebrand landing position. In-plume turbulence causes much of this spread and can increase the maximum spotting distance by a factor of more than 2 over that in a plume without turbulence in our experiments. The substantial impact of plume dynamics on the spotting process implies that fire spread models should include parametrisations of turbulent plume dynamics to improve their accuracy and physical realism.

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Zhou, Kuibin, Sayaka Suzuki, and Samuel L. Manzello. "Experimental Study of Firebrand Transport." Fire Technology 51, no. 4 (May 27, 2014): 785–99. http://dx.doi.org/10.1007/s10694-014-0411-8.

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Trucchia, Andrea, Vera Egorova, Anton Butenko, Inderpreet Kaur, and Gianni Pagnini. "RandomFront 2.3: a physical parameterisation of fire spotting for operational fire spread models – implementation in WRF-SFIRE and response analysis with LSFire+." Geoscientific Model Development 12, no. 1 (January 3, 2019): 69–87. http://dx.doi.org/10.5194/gmd-12-69-2019.

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Abstract. Fire spotting is often responsible for dangerous flare-ups in wildfires and causes secondary ignitions isolated from the primary fire zone, which lead to perilous situations. The main aim of the present research is to provide a versatile probabilistic model for fire spotting that is suitable for implementation as a post-processing scheme at each time step in any of the existing operational large-scale wildfire propagation models, without calling for any major changes in the original framework. In particular, a complete physical parameterisation of fire spotting is presented and the corresponding updated model RandomFront 2.3 is implemented in a coupled fire–atmosphere model: WRF-SFIRE. A test case is simulated and discussed. Moreover, the results from different simulations with a simple model based on the level set method, namely LSFire+, highlight the response of the parameterisation to varying fire intensities, wind conditions and different firebrand radii. The contribution of the firebrands to increasing the fire perimeter varies according to different concurrent conditions, and the simulations show results in agreement with the physical processes. Among the many rigorous approaches available in the literature to model firebrand transport and distribution, the approach presented here proves to be simple yet versatile for application to operational large-scale fire spread models.

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Pokswinski, Scott, Michael R. Gallagher, Nicholas S. Skowronski, E. Louise Loudermilk, Joseph J. O’Brien, and J. Kevin Hiers. "Diurnal Pine Bark Structure Dynamics Affect Properties Relevant to Firebrand Generation." Fire 3, no. 4 (September 25, 2020): 55. http://dx.doi.org/10.3390/fire3040055.

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Firebrands are an important agent of wildfire spread and structure fire ignitions at the wildland urban interface. Bark flake morphology has been highlighted as an important yet poorly characterized factor in firebrand generation, transport, deposition, and ignition of unburned material. Using pine species where bark flakes are the documented source of embers, we conducted experiments to investigate how bark structure changes in response to diurnal drying. Over a three-day period in a longleaf pine (Pinus palustris Mill.) stand in Florida, we recorded changes in temperature, moisture content, and structure of bark across different facing aspects of mature pine trees to examine the effects of varying solar exposure on bark moisture. We further compared results to bark drying in a pitch pine (Pinus rigida Mill.) plantation in New Jersey. Under all conditions, bark peeled and lifted away from the tree trunk over the study periods. Tree bole aspect and the time of day interacted to significantly affect bark peeling. General temperature increases and moisture content decreases were significantly different between east and west aspects in pitch pine, and with time of day and aspect in longleaf pine. These results illustrate that bark moisture and flakiness is highly dynamic on short time scales, driven largely by solar exposure. These diurnal changes likely influence the probability of firebrand production during fire events via controls on moisture (ignition) and peeling (lofting).

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Dal-Ri dos Santos, Iago, and Neda Yaghoobian. "Effects of urban boundary layer turbulence on firebrand transport." Fire Safety Journal 135 (February 2023): 103726. http://dx.doi.org/10.1016/j.firesaf.2022.103726.

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Tohidi, Ali, and Nigel Berkeley Kaye. "Aerodynamic characterization of rod-like debris with application to firebrand transport." Journal of Wind Engineering and Industrial Aerodynamics 168 (September 2017): 297–311. http://dx.doi.org/10.1016/j.jweia.2017.06.019.

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Wadhwani, Rahul, Duncan Sutherland, Andrew Ooi, Khalid Moinuddin, and Graham Thorpe. "Verification of a Lagrangian particle model for short-range firebrand transport." Fire Safety Journal 91 (July 2017): 776–83. http://dx.doi.org/10.1016/j.firesaf.2017.03.019.

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Tohidi, Ali, and Nigel Berkeley Kaye. "Comprehensive wind tunnel experiments of lofting and downwind transport of non-combusting rod-like model firebrands during firebrand shower scenarios." Fire Safety Journal 90 (June 2017): 95–111. http://dx.doi.org/10.1016/j.firesaf.2017.04.032.

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Himoto, Keisuke, and Tatsuya Iwami. "Generalization framework for varying characteristics of the firebrand generation and transport from structural fire source." Fire Safety Journal 125 (October 2021): 103418. http://dx.doi.org/10.1016/j.firesaf.2021.103418.

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Consalvi, J. L., P. Mindykowski, J. P. Vantelon, and B. Porterie. "Scaling the transport of firebrands by wind-blown plumes." Fire Safety Journal 46, no. 1-2 (January 2011): 48–55. http://dx.doi.org/10.1016/j.firesaf.2010.07.005.

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SARDOY, N., J. CONSALVI, B. PORTERIE, and A. FERNANDEZPELLO. "Modeling transport and combustion of firebrands from burning trees." Combustion and Flame 150, no. 3 (August 2007): 151–69. http://dx.doi.org/10.1016/j.combustflame.2007.04.008.

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Himoto, Keisuke, and Takeyoshi Tanaka. "Transport Of Disk-shaped Firebrands In A Turbulent Boundary Layer." Fire Safety Science 8 (2005): 433–44. http://dx.doi.org/10.3801/iafss.fss.8-433.

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Song, Jiayun, Xinyan Huang, Naian Liu, Han Li, and Linhe Zhang. "The Wind Effect on the Transport and Burning of Firebrands." Fire Technology 53, no. 4 (February 4, 2017): 1555–68. http://dx.doi.org/10.1007/s10694-017-0647-1.

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Kortas, S., P. Mindykowski, J. L. Consalvi, H. Mhiri, and B. Porterie. "Experimental validation of a numerical model for the transport of firebrands." Fire Safety Journal 44, no. 8 (November 2009): 1095–102. http://dx.doi.org/10.1016/j.firesaf.2009.08.001.

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Hall, James, Peter F. Ellis, Geoffrey J. Cary, Glenys Bishop, and Andrew L. Sullivan. "Long-distance spotting potential of bark strips of a ribbon gum (Eucalyptus viminalis)." International Journal of Wildland Fire 24, no. 8 (2015): 1109. http://dx.doi.org/10.1071/wf15031.

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Firebrands of ribbon bark eucalypt are notorious for igniting spotfires many kilometres ahead of a bushfire. However, no research to date has demonstrated that this bark type can sustain combustion at its terminal velocity for the travel time required. Fifty samples of shed bark of Eucalyptus viminalis of three distinct morphologies were ignited at one end and burned tethered in a vertical wind tunnel at air velocities approximating their terminal velocity. Mean terminal velocity and burnout time for ‘flat plates’, ‘simple cylinders’ and ‘internally convoluted cylinders’ were 5.4 m s–1 and 251 s; 5.2 m s–1 and 122 s; and 5.8 m s–1 and 429 s. The corresponding maximum burnout times were 785 s, 353 s and 1304 s. One internally convoluted cylinder flamed continuously and consumed its length of 368 mm in 271 s. The maximum burnout time for the internally convoluted cylinders is commensurate with a potential spotting distance exceeding 20 km given a mean wind speed during transport of 60 km h–1. This is the first study in which combustion times exceeding a few minutes have been recorded for this bark morphology, and thus provides some corroboration of the notoriety for long-distance spotting.

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Clark, Kenneth L., Warren E. Heilman, Nicholas S. Skowronski, Michael R. Gallagher, Eric Mueller, Rory M. Hadden, and Albert Simeoni. "Fire Behavior, Fuel Consumption, and Turbulence and Energy Exchange during Prescribed Fires in Pitch Pine Forests." Atmosphere 11, no. 3 (February 29, 2020): 242. http://dx.doi.org/10.3390/atmos11030242.

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Prescribed fires are conducted extensively in pine-dominated forests throughout the Eastern USA to reduce the risk of wildfires and maintain fire-adapted ecosystems. We asked how fire behavior and fuel consumption during prescribed fires are associated with turbulence and energy fluxes, which affect the dispersion of smoke and transport of firebrands, potentially impacting local communities and transportation corridors. We estimated fuel consumption and measured above-canopy turbulence and energy fluxes using eddy covariance during eight prescribed fires ranging in behavior from low-intensity backing fires to high-intensity head fires in pine-dominated forests of the New Jersey Pinelands, USA. Consumption was greatest for fine litter, intermediate for understory vegetation, and least for 1 + 10 hour wood, and was significantly correlated with pre-burn loading for all fuel types. Crown torching and canopy fuel consumption occurred only during high-intensity fires. Above-canopy air temperature, vertical wind velocity, and turbulent kinetic energy (TKE) in buoyant plumes above fires were enhanced up to 20.0, 3.9 and 4.1 times, respectively, compared to values measured simultaneously on control towers in unburned areas. When all prescribed fires were considered together, differences between above-canopy measurements in burn and control areas (Δ values) for maximum Δ air temperatures were significantly correlated with maximum Δ vertical wind velocities at all (10 Hz to 1 minute) integration times, and with Δ TKE. Maximum 10 minute averaged sensible heat fluxes measured above canopy were lower during low-intensity backing fires than for high-intensity head fires, averaging 1.8 MJ m−2 vs. 10.6 MJ m−2, respectively. Summed Δ sensible heat values averaged 70 ± 17%, and 112 ± 42% of convective heat flux estimated from fuel consumption for low-intensity and high-intensity fires, respectively. Surprisingly, there were only weak relationships between the consumption of surface and understory fuels and Δ air temperature, Δ wind velocities, or Δ TKE values in buoyant plumes. Overall, low-intensity fires were effective at reducing fuels on the forest floor, but less effective at consuming understory vegetation and ladder fuels, while high-intensity head fires resulted in greater consumption of ladder and canopy fuels but were also associated with large increases in turbulence and heat flux above the canopy. Our research quantifies some of the tradeoffs involved between fire behavior and turbulent transfer of smoke and firebrands during effective fuel reduction treatments and can assist wildland fire managers when planning and conducting prescribed fires.

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Himoto, Keisuke, and Yoshihiko Hayashi. "Hierarchical Bayesian approach to developing probabilistic models for generation and transport of firebrands in large outdoor fires under limited data availability." Fire Safety Journal 134 (December 2022): 103679. http://dx.doi.org/10.1016/j.firesaf.2022.103679.

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Pagnini, G., and A. Mentrelli. "Modelling wildland fire propagation by tracking random fronts." Natural Hazards and Earth System Sciences Discussions 1, no. 6 (November 19, 2013): 6521–57. http://dx.doi.org/10.5194/nhessd-1-6521-2013.

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Abstract. Wildland fire propagation is studied in literature by two alternative approaches, namely the reaction-diffusion equation and the level-set method. These two approaches are considered alternative each other because the solution of the reaction-diffusion equation is generally a continuous smooth function that has an exponential decay and an infinite support, while the level-set method, which is a front tracking technique, generates a sharp function with a finite support. However, these two approaches can indeed be considered complementary and reconciled. Turbulent hot-air transport and fire spotting are phenomena with a random character that are extremely important in wildland fire propagation. As a consequence the fire front gets a random character, too. Hence a tracking method for random fronts is needed. In particular, the level-set contourn is here randomized accordingly to the probability density function of the interface particle displacement. Actually, when the level-set method is developed for tracking a front interface with a random motion, the resulting averaged process emerges to be governed by an evolution equation of the reaction-diffusion type. In this reconciled approach, the rate of spread of the fire keeps the same key and characterizing role proper to the level-set approach. The resulting model emerges to be suitable to simulate effects due to turbulent convection as fire flank and backing fire, the faster fire spread because of the actions by hot air pre-heating and by ember landing, and also the fire overcoming a firebreak zone that is a case not resolved by models based on the level-set method. Moreover, from the proposed formulation it follows a correction for the rate of spread formula due to the mean jump-length of firebrands in the downwind direction for the leeward sector of the fireline contour.

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Pagnini, G., and A. Mentrelli. "Modelling wildland fire propagation by tracking random fronts." Natural Hazards and Earth System Sciences 14, no. 8 (August 28, 2014): 2249–63. http://dx.doi.org/10.5194/nhess-14-2249-2014.

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Abstract. Wildland fire propagation is studied in the literature by two alternative approaches, namely the reaction–diffusion equation and the level-set method. These two approaches are considered alternatives to each other because the solution of the reaction–diffusion equation is generally a continuous smooth function that has an exponential decay, and it is not zero in an infinite domain, while the level-set method, which is a front tracking technique, generates a sharp function that is not zero inside a compact domain. However, these two approaches can indeed be considered complementary and reconciled. Turbulent hot-air transport and fire spotting are phenomena with a random nature and they are extremely important in wildland fire propagation. Consequently, the fire front gets a random character, too; hence, a tracking method for random fronts is needed. In particular, the level-set contour is randomised here according to the probability density function of the interface particle displacement. Actually, when the level-set method is developed for tracking a front interface with a random motion, the resulting averaged process emerges to be governed by an evolution equation of the reaction–diffusion type. In this reconciled approach, the rate of spread of the fire keeps the same key and characterising role that is typical of the level-set approach. The resulting model emerges to be suitable for simulating effects due to turbulent convection, such as fire flank and backing fire, the faster fire spread being because of the actions by hot-air pre-heating and by ember landing, and also due to the fire overcoming a fire-break zone, which is a case not resolved by models based on the level-set method. Moreover, from the proposed formulation, a correction follows for the formula of the rate of spread which is due to the mean jump length of firebrands in the downwind direction for the leeward sector of the fireline contour. The presented study constitutes a proof of concept, and it needs to be subjected to a future validation.

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Thomas, Jan C., Eric V. Mueller, Michael R. Gallagher, Kenneth L. Clark, Nicholas Skowronski, Albert Simeoni, and Rory M. Hadden. "Coupled Assessment of Fire Behavior and Firebrand Dynamics." Frontiers in Mechanical Engineering 7 (December 16, 2021). http://dx.doi.org/10.3389/fmech.2021.650580.

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The hazards associated with firebrands have been well documented. However, there exist few studies that allow for the hazard from a given fire to be quantified. To develop predictive tools to evaluate this hazard, it is necessary to understand the conditions that govern firebrand generation and those that affect firebrand deposition. A method is presented that allows for time-resolved measurements of fire behavior to be related to the dynamics of firebrand deposition. Firebrand dynamics were recorded in three fires undertaken in two different ecosystems. Fire intensity is shown to drive firebrand generation and firebrand deposition—higher global fire intensities resulting in the deposition of more, larger firebrands at a given distance from the fire front. Local firebrand dynamics are also shown to dominate the temporal firebrand deposition with periods of high fire intensity within a fire resulting in firebrand shower at deposition sites at times commensurate with firebrand transport. For the range of conditions studied, firebrand deposition can be expected up to 200 m ahead of the fire line based on extrapolation from the measurements.

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Thompson, Dan K., Daniel A. Yip, Eunmo Koo, Rod Linn, Ginny Marshall, Razim Refai, and Dave Schroeder. "Quantifying Firebrand Production and Transport Using the Acoustic Analysis of In-Fire Cameras." Fire Technology, February 2, 2022. http://dx.doi.org/10.1007/s10694-021-01194-y.

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AbstractFirebrand travel and ignition of spot fires is a major concern in the Wildland-Urban Interface and in wildfire operations overall. Firebrands allow for the efficient breaching across fuel-free barriers such as roads, rivers and constructed fuel breaks. Existing observation-based knowledge on medium-distance firebrand travel is often based on single tree experiments that do not replicate the intensity and convective updraft of a continuous crown fire. Recent advances in acoustic analysis, specifically pattern detection, has enabled the quantification of the rate at which firebrands are observed in the audio recordings of in-fire cameras housed within fire-proof steel boxes that have been deployed on experimental fires. The audio pattern being detected is the sound created by a flying firebrand hitting the steel box of the camera. This technique allows for the number of firebrands per second to be quantified and can be related to the fire's location at that same time interval (using a detailed rate of spread reconstruction) in order to determine the firebrand travel distance. A proof of concept is given for an experimental crown fire that shows the viability of this technique. When related to the fire's location, key areas of medium-distance spotting are observed that correspond to regions of peak fire intensity. Trends on the number of firebrands landing per square metre as the fire approaches are readily quantified using low-cost instrumentation.

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Atwood, Loren, and Natalie Wagenbrenner. "A numerical investigation exploring the potential role of porous fencing in reducing firebrand impingement on homes." Frontiers in Mechanical Engineering 8 (December 15, 2022). http://dx.doi.org/10.3389/fmech.2022.1059018.

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Firebrand impingement is a leading cause of home ignitions from wildland fire. The use of porous fencing has recently been proposed as a potential method for mitigating firebrand impingement on homes. A porous fence can act as a windbreak to alter the near-surface flow and induce particle deposition, as demonstrated in other applications, such as the use of snow fences to protect roadways from drifting snow. Conservation advocates have proposed the use of fire-resistant vegetation to act as a fence upwind of homes or subdivisions. Porous fences could also be constructed from fire-resistant materials such as metal, rock, or composites. This numerical investigation of the effectiveness of porous fencing to reduce firebrand impingement on homes conducted a series of experiments to explore the effect of porous fencing on the near-surface flow field and firebrand transport downwind of the fence. We also evaluated the sensitivity of the results to various fence, flow, and firebrand properties, including fence height, fence porosity, wind speed, firebrand source location, and firebrand size. To our knowledge, this is the first study to investigate the concept of using a fence to induce firebrand deposition upwind of homes. Our results showed that porous fencing can reduce firebrand impingement on homes by up to 35% under certain conditions; however, fencing can also increase impingement on homes. The mitigation effectiveness depended on the proximity of the firebrand source, distance between the fence and home as a function of fence height, wind speed, and firebrand size. A series of key findings and recommendations are provided.

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Wadhwani, R., D. Sutherland, A. Ooi, and K. Moinuddin. "Firebrand transport from a novel firebrand generator: numerical simulation of laboratory experiments." International Journal of Wildland Fire, 2022. http://dx.doi.org/10.1071/wf21088.

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Wadhwani, Rahul, Catherine Sullivan, Amila Wickramasinghe, Matthew Kyng, Nazmul Khan, and Khalid Moinuddin. "A review of firebrand studies on generation and transport." Fire Safety Journal, September 2022, 103674. http://dx.doi.org/10.1016/j.firesaf.2022.103674.

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Bean, Derek, and David L. Blunck. "Sensitivities of Porous Beds and Plates to Ignition by Firebrands." Frontiers in Mechanical Engineering 7 (August 5, 2021). http://dx.doi.org/10.3389/fmech.2021.653810.

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The increasing occurrence of severe wildfires, coupled with the expansion of the wildland urban interface has increased the number of structures in danger of being destroyed by wildfires. Ignition by firebrands is a significant avenue for fire spread and structure loss; thus, understanding processes and parameters that control the ignition of fuel beds by firebrands is important for reducing these losses. In this study the effect of fuel bed characteristics (i.e., particle size and porous or solid fuel bed) on ignition behavior was considered. Modelling and analysis was conducted to better understand parameters that are dominant in controlling ignition. The fuel beds, made from Douglas-fir shavings, Douglas-fir plates, or cardboard plates, were heated with a cartridge heater (i.e., surrogate firebrand) to observe ignition. Smaller particles were observed to ignite more readily in porous beds than larger particles when heat transfer from the heater is primarily through conduction. This occurs in large part due to differences in contact area between the fuel bed and the heater coupled with thermal properties of the fuel bed. As particle sizes increased, ignition was more likely to occur at extended times (>100 s) due to the increased importance of radiation heat transfer. Douglas-fir plates were primarily observed to ignite at times where conduction was the dominant mode of heat transfer (<10 s). Heat flux delivered to the fuel bed was observed to be a more accurate predictor of ignition likelihood and ignition time than heater temperatures. The characteristic ratio of transport and chemical timescales can be used, in conjunction with the measured heat flux and thermal diffusivity of the fuel beds, as a first approximation to predict ignition for the porous fuel beds. This suggests that future work focusing on these parameters may produce a general characterization of fuel bed ignition probability across fuel beds materials and morphologies.

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