Experimental Measurements of Upward Flame Spread on a Vertical Wall With External Radiation.
Experimental Measurements of Upward Flame Spread on a
Vertical Wall With External Radiation.
(1172 K)
Brehob, E. G.; Kulkarni, A. K.
Fire Safety Journal, Vol. 31, No. 3, 181-200, October
1998.
Sponsor:
National Institute of Standards and Technology,
Gaithersburg, MD
Keywords:
flame spread; walls; flame height; heating; thickness
Abstract:
The overall objective of the project is to gain an
understanding of the flame spread phenomenon under
simulated surrounding fire conditions. In this phase of
the project, emphasis is placed on obtaining
experimental data for upward flame spread with applied
external radiation on practical wall materials. A
second phase (not yet reported) is the development of a
numerical flame spread model and the experimental
results presented here will be used for comparison with
model predictions. Flame height, and in some cases
pyrolysis height, were recorded as functions of time for
120 cm x 30 cm samples; and these data were used to
quantitatively investigate the effect of external
radiation on several materials. Infrared heating panels
were used to supply radiant fluxes of up to 15 kW/m2 to
the sample. Many wood-based materials do not exhibit
flame spread to the top of the sample when ignited
without applied external flux. With moderate levels of
external radiation (5-10 kW/m2), many of these materials
sustained flame spread to the top of the sample. With
increasing external radiation levels, flame spread was
also more rapid. A comprehensive series of tests was
run on particle board to investigate the effect of
igniter strength, preheat of the sample, and sample
thickness. Igniter strength was not a significant
factor and did not cause the flame spread to be
sustained; the effect of preheat, even at moderate
levels of radiant flux, was important; and sample
thickness had a slight effect, with thicker samples
burning slower. Total heat feedback to the sample was
measured and the maximum values for various samples are
reported. Experimental data obtained in this project
will be used to aid in the development and validation of
a numerical flame spread model.
Building and Fire Research Laboratory
National Institute of Standards and Technology
Gaithersburg, MD 20899