Ignition of Mulch and Grasses by Firebrands in Wildland-Urban Interface Fires.
Ignition of Mulch and Grasses by Firebrands in
Wildland-Urban Interface Fires.
Manzello, S. L.; Cleary, T. G.; Shields, J. R.; Yang, J.
International Journal of Wildland Fire, Vol. 15, No. 3,
wildland/urban interface; ignition; firebrands; mulch;
grasses; fuel beds; wildland fires; urban fires;
Firebrands or embers are produced as trees and
structures burn in wildlandDSurban interface (WUI) fires.
It is believed that firebrand showers created in WUI
fires may ignite vegetation and mulch located near homes
and structures. This, in turn, may lead to ignition of
homes and structures due to burning vegetation and
mulch. Understanding the ignition events that are due to
firebrands is important to mitigate fire spread in
communities. To assess the ignition propensity of such
materials, simulated firebrands of uniform geometry, but
in two different sizes, were allowed to impinge on fuel
beds of shredded hardwood mulch, pine straw mulch, and
cut grass. The moisture content of these materials was
varied. Firebrands were suspended and ignited within the
test cell of the Fire Emulator/Detector Evaluator
(FE/DE) apparatus. The FE/DE was used to investigate the
influence of an air flow on the ignition propensity of a
fuel bed. Ignition regime maps were generated for each
material tested as a function of impacting firebrand
size, number of deposited firebrands, air flow, and
material moisture content.