Firebrand Generation From Burning Vegetation.
Firebrand Generation From Burning Vegetation.
(1143 K)
Manzello, S. L.; Maranghides, A.; Mell, W. E.
International Journal of Wildland Fire, Vol. 16, No. 4,
458-462, 2007.
Keywords:
vegetation; fire brands; size distribution; mass
distribution; forestry; experiments; moisture contnet;
water
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.
