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Brand Propagation From Large-Scale Fires.

pdf icon 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.


National Institute of Standards and Technology, Gaithersburg, MD


large scale fire tests; equations; propagation; velocity; conservation


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.