Experimental Investigation of Firebrands: Generation and Ignition of Fuel Beds.
Experimental Investigation of Firebrands: Generation
and Ignition of Fuel Beds.
(354 K)
Manzello, S. L.; Cleary, T. G.; Shields, J. R.;
Maranghides, A.; Mell, W. E.; Yang, J. C.
Fire Safety Journal, Vol. 43, No. 3, 226-233, March
2008.
Keywords:
fire brands; fuel beds; ignition; experiments; heat
release rate; moisture content; wildland urban
interface; computational fluid dynamics
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 results of the
real scale fire experiments were used to determine
firebrand sizes to perform reduced
scale ignition studies of fuel beds in contact with
burning firebrands. The firebrand ignition apparatus
allowed for the ignition and
deposition of both single and multiple firebrands onto
the target fuel bed. The moisture content of the fuel
beds used was varied and the
fuels considered were pine needle beds, shredded paper
beds, and shredded hardwood mulch. Firebrands were
constructed by machining
wood (Douglas Fir) into small cylinders of uniform
geometry and the size of the cylinders was varied. The
firebrand ignition apparatus
was installed into the Fire Emulator/Detector Evaluator
(FE/DE) to investigate the influence of an air flow on
the ignition propensity of
fuel beds. Results of this study are presented and
compared to relevant studies in the literature.
Building and Fire Research Laboratory
National Institute of Standards and Technology
Gaithersburg, MD 20899