Brand Propagation From Large-Scale Fires.
Brand Propagation From Large-Scale Fires.
(1115 K)
Woycheese, J. P.; Pagni, P. J.; Liepmann, D.
Journal of Fire Protection Engineering, Vol. 10, No. 2,
32-44, 1999.
Sponsor:
National Institute of Standards and Technology,
Gaithersburg, MD
Keywords:
large scale fire tests; equations; propagation;
velocity; conservation
Abstract:
This paper is one of a series on brand lofting and
propagation. Here, spherical brand propagation in a
constant ambient wind is addressed. Maximum propagation
distances are calculated for wooden brands with
diameters up to 0.18 m, which are lofted above
axisymmetric pool fires with heat release rates, Qo,
between 1 MW and 3 GW. Winds of 1.8 m/s < 92 m/s are
considered. A maximum propagation distance equation is
developed as a function of Qo, Uw and wood type, or
beta. Cedar brands (beta = l), lofted by fires with Qo
= 1 MW, 50 MW and 1 GW, travel a maximum of 49 m, 290 m
and 1100 m, respectively, in 10 m/s winds before landing
at burn out. Brands between a "collapse" diameter and a
maximum loftable diameter propagate the same maximum
distance, since the larger brands move slower and
therefore have more time to combust. Hence, only brands
with 0 < d < dcol need be studied for given Qo, Uw and
beta.
Building and Fire Research Laboratory
National Institute of Standards and Technology
Gaithersburg, MD 20899