Effect of particle orientation and of flow velocity on the combustibility of Pinus pinaster and Eucalyptus globulus firebrand materialMiguel Almeida A , Domingos Xavier Viegas A B D , Ana Isabel Miranda C and Valeria Reva A
A ADAI/LAETA, Associação para o Desenvolvimento da Aerodinâmica Industrial, Rua Pedro Hispano, 12, 3030-289 Coimbra, Portugal.
B Department of Mechanical Engineering, University of Coimbra, Rua Luís Reis dos Santos, 3030-788 Coimbra, Portugal.
C CESAM, Department of Environment and Planning, University of Aveiro, 3810-193 Aveiro, Portugal.
D Corresponding author. Email: email@example.com
International Journal of Wildland Fire 20(8) 946-962 https://doi.org/10.1071/WF09080
Submitted: 21 July 2009 Accepted: 21 April 2011 Published: 5 October 2011
Spotting is a very important mechanism of forest fire spread. Its negative effect increases in extreme fire danger conditions. In order to predict the maximum spotting distance, the duration of the combustion reaction of potential firebrands should be evaluated. This paper reports the results of an experimental laboratory study of the combustibility of firebrand material (pine cones and scales and pieces of bark of eucalypt) of two representative species in Portugal, Pinus pinaster Ait. and Eucalyptus globulus Labill. The main purpose was to assess the role on the burning conditions of the firebrand particle orientation angle θ in relation to the airflow and of the flow velocity (U) around the particle. Tests were made varying the angle of orientation of the main axis of the particle in relation to incident flow in the range of ±90°; flow velocities were tested from 0 to 6.5 m s–1. After ignition, particle mass loss owing to flaming or glowing combustion of the particle was continuously measured. Residual mass, duration of the flaming phase and the burnout times are reported for each case. Empirical models to estimate the trends of variation of some of these parameters with θ and U are proposed to illustrate their importance for the range of test conditions.
Additional keywords: embers, eucalypt bark, firebrands, forest fires, pine cone, pine scale, spot fires.
ReferencesAlbini FA (1979) Spot fire distance from burning trees – a predictive model. USDA Forest Service, Intermountain Forest and Range Experiment Station, General Technical Report GTR-INT-56. (Ogden, UT)
Albini FA (1981) Spot fire distance from isolated sources – extensions of a predictive model. USDA Forest Service, Intermountain Forest and Range Experiment Station, Research Note RN-INT-309. (Ogden, UT)
Albini FA (1983) Transport of firebrands by line thermals. Combustion Science and Technology 32, 277–288.
| Transport of firebrands by line thermals.CrossRef |
Albini FA (1983b) Potential spotting distance from wind – driven surface fires. USDA Forest Service, Intermountain Forest and Range Experiment Station, Research Paper RP-INT-309. (Ogden, UT)
Anthenien RA, Tse SD, Fernandez-Pello AC (2006) On the trajectories of embers initially elevated or lofted by small scale ground fire plumes in high winds. Fire Safety Journal 41, 349–363.
| On the trajectories of embers initially elevated or lofted by small scale ground fire plumes in high winds.CrossRef |
Butler B, Bartlette R, Bradshaw L, Cohen J, Andrews P, Putnam T, Mangan R (1998) Fire behavior associated with the 1994 South Canyon Fire on Storm King Mountain, Colorado. USDA Forest Service, Rocky Mountain Research Station, Research Paper RMRS-RP-9. (Ogden, UT)
Clements HB (1977) Lift-off of forest firebrands. USDA Forest Service, Southeastern Forest Experiment Station, Research Paper SE-159. (Asheville, NC)
Ellis PF (2000) The aerodynamic and combustion characteristics of eucalypt bark – a firebrand study. PhD dissertation. Australian National University, Canberra, ACT.
Fletcher TH, Picket BM, Smith SG, Spittle GS, Woodhouse MM, Haake E, Weise DR (2007) Effects of moisture on ignition behavior of moist California chaparral and Utah leaves. Combustion Science and Technology 179, 1183–1203.
| Effects of moisture on ignition behavior of moist California chaparral and Utah leaves.CrossRef | 1:CAS:528:DC%2BD2sXltF2ntLo%3D&md5=fc36a018ee36a2f843f393ce8f09e7e8CAS |
Fonda RW, Varner JM (2004) Burning characteristics of cones from eight pine species. Northwest Science 78, 322–333. .
Koo E, Pagni P, Weise D, Woicheese J (2010) Firebrands and spotting ignition in large-scale fires. International Journal of Wildland Fire 19, 818–843.
| Firebrands and spotting ignition in large-scale fires.CrossRef |
Manzello S, Cleary T, Shields J, Yang J (2006) Ignition of mulch and grasses by firebrands in wildland–urban interface fires. International Journal of Wildland Fire 15, 427–431.
| Ignition of mulch and grasses by firebrands in wildland–urban interface fires.CrossRef |
Manzello S, Maranghides A, Mell EM (2007) Firebrand generation from burning vegetation. International Journal of Wildland Fire 16, 458–462.
| Firebrand generation from burning vegetation.CrossRef |
Muraszew A, Fedele JB, Kuby WC (1975) Firebrand investigation. The Aerospace Corporation, Aerospace Report ATR-75 (7470)–1. (El Segundo, CA)
Pagni PJ, Woicheese JP (2000) Fire spread by brand spotting. In ‘15th Meeting of the UJNR Panel on Fire Research and Safety’, 1–7 March 2000, San Antonio, TX. (Ed. SL Bryner) Vol. 2. NISTIR 6588, pp. 373–380. (National Institute of Standards and Technology) Available at http://fire.nist.gov/bfrlpubs/fire00/PDF/f00131.pdf [Verified 27 September 2011]
Pereira da Silva W, Diniz da Silva CM (2009) LAB fit curve fitting software (nonlinear regression and treatment of data program) Ver. 7.2.46. Available at www.labfit.net [Verified 15 August 2011]
Pickett B, Isackson C, Wunder R, Fletcher T, Butler B, Weise D (2009) Flame interactions and burning characteristics of two live leaf samples. International Journal of Wildland Fire 18, 865–874.
| Flame interactions and burning characteristics of two live leaf samples.CrossRef | 1:CAS:528:DC%2BD1MXhtlWht7fN&md5=26a5ca9c5fcbaa1e7f0375f2ffb07d05CAS |
Pickett B, Isackson C, Wunder R, Fletcher T, Butler B, Weise D (2010) Experimental measurements during combustion of moist individual foliage samples. International Journal of Wildland Fire 19, 153–162.
| Experimental measurements during combustion of moist individual foliage samples.CrossRef | 1:CAS:528:DC%2BC3cXjvF2msLw%3D&md5=96dc2c8caba02377c458f2679631f8feCAS |
Pita LP, Viegas DX, Gaspar S, Schuman J (2010) Fuel beds ignition by Eucalyptus bark. In ‘6th International Conference on Forest Fire Research’, 15–18 November 2010, Coimbra, Portugal. (Ed. DX Viegas) (CD-ROM) (Associação para o Desenvolvimento da Aerodinâmica Industrial (ADAI): Coimbra, Portugal)
Rothermel R (1993) Mann Gulch fire: a race that couldn’t be won. USDA Forest Service, Intermountain Research Station, General Technical Report INT-299. (Ogden, UT)
Sardoy N, Consalvi J, Porterie B, Fernandez-Pello A (2007) Modelling transport and combustion of firebrands from burning trees. Combustion and Flame 150, 151–169.
| Modelling transport and combustion of firebrands from burning trees.CrossRef | 1:CAS:528:DC%2BD2sXnsVSrtrY%3D&md5=28c02f72cfb4ba7d699a39bb7de64b9bCAS |
Tarifa CS, Del Notario PP, Moreno FG, Villa AR (1967) Transport and combustion of firebrands. USDA Forest Service, Reports of Grants FG-SP-114 and FG-SP-146.
Viegas DX, Ribeiro LM, Viegas MT, Pita LP, Rossa C (2009) Impacts of fire on society: extreme fire propagation issues. In ‘Earth Observation of Wildland Fires in Mediterranean Ecosystems’. (Ed. E Chuvieco) pp. 97–110. (Springer-Verlag: New York)
Weber RO, De Mestre NJ (1990) Flame spread measurements on single ponderosa pine needles: effect of sample orientation and concurrent external flow, Combustion Science and Technology 70, 17–32.
| Flame spread measurements on single ponderosa pine needles: effect of sample orientation and concurrent external flow,CrossRef |