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Analysis on Downwind Distribution of Firebrands Sourced from a Wildland Fire

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Abstract

Generation of firebrands from a wildland fire and their distribution downwind are studied using an analytical approach. The processes considered include emission of firebrands, wind-driven transport and the associated spot ignition. Emission of the firebrands from a fire front is treated as a stochastic process reflecting the interaction between gas flow plume and the burning fuel debris formed, with the emission rate being dominated by the rate of fuel consumption, emission factor and a function of firebrand sizes. Analogous to the random distribution of non-burning windborne particles, the transient distribution of firebrands downwind is described by a statistical pattern of Rayleigh form. Number and mass of firebrands landed downwind within the maximum travel distance are then determined by integration over the entire impact period during fire spread and burning-out processes. Application of the model to the bushfire occurred in Canberra, Australia in 2003 indicates that this model provides reasonable prediction in the distribution of firebrands downwind, and quantitatively exhibits the role of ember attack in massive destruction of houses at urban interface.

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Abbreviations

A s :

Maximum cross-section area of a firebrand (m2)

C d :

Drag coefficient of a firebrand in flowing air (0.45)

F e :

Firebrand emission factor for specific wildland fuels (kg−1)

g :

Acceleration of gravity (m s−2)

G(r i ):

Rate of firebrands emitted from a fire source (m−2 s−1)

H c :

Heat of combustion of wildland fuels (18,620 kJ kg−1) [1]

hmax(r i ):

Height travelled by a firebrand with radius r i (m)

I b :

Fireline intensity (kW m−1)

L f :

Flame length (m)

M(x i  − x0):

Mass of firebrands distributed downwind at a location of x i  − x 0 (kg m−2)

m cr :

Critical mass of firebrands leading to successful ignition of the objects contacted (6.0 g)

\( \dot{m}_{f} \) :

Fuel consumption rate in combustion zone determined by I b /H c (kg m−1 s−1)

N(x i  − x0):

Number of firebrands distributed downwind at a location of x i  − x 0 (m−2)

p(r i , x):

Distribution function of firebrands with radius between r i and r i  + dr i (m−1)

P f :

Ignition probability of houses downwind

r :

Radius (m)

r 0 :

Brand radius with the highest frequency of appearance (0.012 m)

r i :

Brand radius (m)

r max :

Maximum loftable brand radius (m)

r min :

Minimum radius of lofted brands that play a role in igniting the objects contacted (m)

t :

Time (s)

t b :

Entire impact period of fire spread and the subsequent fire burning out (s)

t c :

Burning duration of a firebrand (s)

t r :

Flame residence time (s)

t s :

Duration of fire spread (s)

U g :

Up-draught gas velocity (m s−1)

U t :

Terminal velocity of a firebrand at fall in still air (m s−1)

U w :

Environmental wind speed (m s−1)

v f :

Rate of fire spread (m s−1)

V s :

Volume of a firebrand (m3)

x 0 :

Distance between the initial firefront and the edge of the vegetations or the targeted area (m)

x i :

Distance between a fire front and a target considered (m)

β :

A correction factor (0.7)

δ(r i ):

A parameter in association with the function p(r i , x) (m)

η :

A coefficient determined based upon experimental results of Tarifa et al. [2] (0.435 mm2 s−1)

θ f :

Angle of flame surface to the vertical

λ :

A constant determined based upon an experimental curve reported by Tarifa et al. [2] (2.86×10−4 s−2)

ρ a :

Density of ambient air (1.2 kg m−3)

ρ s :

Density of wildland fuels (542 kg m−3)

σ :

A constant evaluated as 0.37

χ :

A hardness factor for alive pine trees to liberate firebrands (0.15)

References

  1. Pyne SJ, Andrews PL, Laven RD (1996) Introduction to Wildland Fire (2nd ed.). John Wiley & Sons, New York.

    Google Scholar 

  2. Tarifa CS, Del Notario PP, Moreno FG (1965) On the flight paths and lifetimes of burning particles of wood. In: Proc. of Tenth Symp (Inter) on Combust, The Combustion Institute, Pittsburgh, PA, pp 1021–1037

  3. Muraszew A (1974) Firebrand phenomena. Aerospace Report No. ATR-74(8165-01)-1. The Aerospace Corp., El Segundo, CA

  4. Albini FA (1979) Spot fire distance from burning trees—a predictive model. USDA Forest Service General Technical Report INT-56. Intermountain Forest and Range Experiment Station, Ogden, UT

  5. Woycheese JP, Pagni PJ, Liepman D (1997) Brand lofting above large-scale fires. In: Proc 2nd Inter Conf on Fire Res and Eng, Society of Fire Protection Engineers, Boston, MA, pp 137–150

  6. Woycheese JP, Pagni PJ, Liepmann D (1999) Brand propagation from large-scale fires. J Fire Prot Eng 10(2):32–44.

    Article  Google Scholar 

  7. Ellis PF (2000) The aerodynamic and combustion characteristics of Eucalypt bark—a firebrand study. PhD thesis, Australian National University, Canberra, ACT, Australia

  8. Sardoy N, Consalvi JL, Kaiss A, Fernandez-Pello AC, Porterie B (2008) Numerical study of ground-level distribution of firebrands generated by line fires. Combust Flame 154(3):478–488.

    Article  Google Scholar 

  9. Dowling VP (1994) Ignition of timber bridges in bushfires. Fire Safety J 22:145–168.

    Article  Google Scholar 

  10. Manzello SL, Cleary TG, Shields JR, Yang JC (2006) On the ignition of fuel beds by firebrands. Fire Mater 30(1):77–87.

    Article  Google Scholar 

  11. Manzello SL, Maranghides A, Shields JR, Mell WE, Cleary TG, Yang JC (2006) Firebrand production from burning vegetation. In: Proc. 5th Inter Conf on Forest Fire Research, Luso, Coimbra, Portugal

  12. Manzello SL, Maranghides A, Shields JR, Mell WE, Hayashi Y, Nii D (2007) Measurement of firebrand production and heat release rate (HRR) from burning Korean pine trees. In: Proc. 7th Asia-Oceania Symp on Fire Sci & Tech, Hong Kong Polytechnic University, Hong Kong

  13. CFFP (2001) Project Vesta: Spotfire project, Bushfire behaviour and management, CSIRO Forestry and Forest Products, Kingston, ACT, Australia. http://www.ffp.csiro.au/nfm/fbm/vesta/spotfire.html. Accessed 2006

  14. Hage KD (1961) On the dispersion of large particles from a 15-m source in the atmosphere. J Meteor 18:534–539.

    Google Scholar 

  15. Pasquill F (1974) Atmospheric diffusion. The dispersion of windborne material from industrial and other sources (2nd ed.), Ellis Horwood Limited, Chichester, England.

    Google Scholar 

  16. Hashem A, Parkin CS (1991) A simplified heavy particle random-walk model for the prediction of drift from agricultural sprays. Atmos Environ 25A(8):1609–1614.

    Google Scholar 

  17. Himoto K, Tanaka T (2005) Transport of disk-shaped firebrands in a turbulent boundary layer. In: Proc. of 8th Symp on Fire Safety Sci, IAFSS, Beijing, China, pp 433–444

  18. Clements HB (1977) Lift-off of forest firebrands. USDA Forest Service Research Paper SE-159. Southeastern Forest Experiment Station, Asheville, NC

  19. Raupach MR (1990) Similarity analysis of the interaction of bushfire plumes with ambient winds. Math Comput Modelling 12(12):113–121.

    Article  Google Scholar 

  20. Boman C, Pettersson E, Nordin A, Westerholm R, Boström D (2006) Gaseous and particulate emissions from residential wood log and pellet stoves—experimental characterization and quantification. To be published

  21. Thomas PH (1971) Rates of spread of some wind-driven fires. Forestry 44:155–175.

    Article  Google Scholar 

  22. Pagni PJ, Peterson TG (1974) Flame spread through porous fuels. In: Proc. 14th Symp (Inter) on Combustion, The Combustion Institute, Pittsburgh, PA, pp 1099–1107

  23. Wang H-H (2006) Ember attack: its role in the destruction of houses during ACT Bushfire in 2003. In: Proc Bushfire Conf 2006—Life in a Fire-prone Environment: Translating Science into Practice, Griffith University, Brisbane, Queensland, Australia

  24. Alexander ME (1982) Calculating and interpreting forest fire intensities. Can J Bot 60:349–357.

    Article  Google Scholar 

  25. Vodvarka F (1969) Firebrand field studies. IIT Research Institute Final technical report, Project J6148, Chicago, IL

  26. Alexandrian D (2002) A probabilistic model for forecasting spot fires. In: Proc. 4th Inter Conf on Forest Fire Res and 2002 Wildland Fire Safety Summit, Luso, Coimbra, Portugal

  27. Moran R (2003) Canberra firestorm: 18th January 2003. Channel 9 News Bureau, Canberra, ACT, Australia.

    Google Scholar 

  28. Blanchi R, Leonard JE (2005) Investigation of bushfire attack mechanisms resulting in house loss in the ACT bushfire 2003. Report for Bushfire CRC, CSIRO Manufacturing and Infrastructure Technology, Highett, VIC, Australia

  29. Chen K, McAneney J (2004) Quantifying bushfire penetration into urban areas in Australia. Geophys Res Lett 31:L12212.

    Article  Google Scholar 

  30. Doogan M (2006) The Canberra firestorm: Inquests and inquiry into four deaths and four fires between 8 and 18 January 2003. ACT Coroners Court, ACT, Australia.

    Google Scholar 

  31. McRae RHD (2004) The breath of dragon—Observations of the January 2003 ACT Bushfires. Emergency Services Bureau, ACT, Australia.

    Google Scholar 

  32. Livbom A (2005) Fire phenomena at wildland/urban interface: an analysis based on post fire survey of Canberra Fire 2003. Industrial placement report for final-year university study in Sweden, CSIRO Manufacturing and Materials Technology, Highett, VIC, Australia

  33. Waterman TE (1969) Experimental study of firebrand generation. IIT Research Institute Final technical report, Project J6130, Chicago, IL

  34. Wang H-H, Zhang L-H, Liu N-A (2006) Impact of wind on the geometries and temperature profiles of fire plumes formed in bushfires. A Scientific Visit funded by Australian Academy of Science and China Academy of Sciences, State Key Lab of Fire Science, Univ of Sci & Tech of China, Hefei, Anhui, China

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  1. Urban Systems Program, CSIRO Sustainable Ecosystems, P.O. Box 310, North Ryde, NSW, 1670, Australia

    Hai-Hui Wang

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Wang, HH. Analysis on Downwind Distribution of Firebrands Sourced from a Wildland Fire. Fire Technol 47, 321–340 (2011). https://doi.org/10.1007/s10694-009-0134-4

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