Firebrand generation from burning vegetation1
Samuel L. Manzello A B , Alexander Maranghides A and William E. Mell AA Building and Fire Research Laboratory (BFRL), National Institute of Standards and Technology (NIST), Gaithersburg, MD 20899-8662, USA.
B Corresponding author. Email: samuelm@nist.gov
International Journal of Wildland Fire 16(4) 458-462 https://doi.org/10.1071/WF06079
Submitted: 16 May 2006 Accepted: 20 February 2007 Published: 20 August 2007
Abstract
A series of real-scale fire experiments were performed to determine the size and mass distribution of firebrands generated from Douglas-fir (Pseudotsuga menziesii) trees. The experiments were performed in the Large Fire Laboratory at the National Institute of Standards and Technology. The Douglas-fir trees used for the experiments ranged in total height from 2.6 to 5.2 m and the tree moisture content was varied. An array of pans filled with water was used to collect the firebrands that were generated from the burning trees. This ensured that firebrands would be quenched as soon as they made contact with the pans. The firebrands were subsequently dried and the sizes were measured using callipers and the dry mass was determined using a precision balance. For all experiments performed, the firebrands were cylindrical in shape. The average firebrand size measured from the 2.6-m Douglas-fir trees was 3 mm in diameter, 40 mm in length. The average firebrand size measured for the 5.2-m Douglas-fir trees was 4 mm in diameter with a length of 53 mm. The mass distribution of firebrands produced from two different tree sizes under similar tree moisture levels was similar. The only noticeable difference occurred in the largest mass class. Firebrands with masses up to 3.5 g to 3.7 g were observed for the larger tree height used (5.2 m). The surface area of the firebrands scaled with firebrand weight.
Additional keywords: firebrand collection, size and mass distribution, tree burns.
Acknowledgements
The assistance of LFL staff at NIST is much appreciated. In particular, the assistance of Mr. Laurean DeLauater, Mr. Edward Hnetovsky, and Mr. Jack Lee is acknowledged. Mr. Marco G. Fernandez and Mr. J. Shields were also helpful in performing these experiments. Dr Ronald Rehm of BFRL-NIST is acknowledged for helpful discussions. The reviewers are acknowledged for providing detailed comments to strengthen the quality of the manuscript.
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1 Official contribution of the National Institute of Standards and Technology; not subject to copyright in the United States of America.
2 Certain commercial equipment are identified to accurately describe the methods used; this in no way implies endorsement from NIST.
