Upward Flame Spread Along the Vertical Corner Walls. Final Report.
Upward Flame Spread Along the Vertical Corner Walls.
Qian, C.; Ishida, H.; Saito, K.
NIST GCR 94-648; 45 p. June 1994.
Sponsor:National Institute of Standards and Technology,
Available from: National Technical Information Service
Order number: PB94-206299
corners; flame spread; heat flux; polymethyl
methacrylate; pyrolysis temperature; walls
Flame spread behavior and the pyrolysis region spread
characteristics along vertical corner walls were studied
in detail with an automated infrared imaging temperature
measurement technique (IR technique). The technique was
recently developed for the measurement of transient
pyrolysis temperature on both charring and non-charring
materials. Temporal isotherms on PMMA samples were
successfully obtained, from which the progress rate of
the pyrolysis front was automatically deduced. It was
found that the pyrolysis front shape was always
M-shaped, i.e., no spread along the corner, and the
maximum spread is in a few centimeters away from the
corner. Understanding of the mechanism of the M-shape
formation is important in developing a prediction model
of the spread rate. Four possible mechanisms were
identified and flame displacement effects are found to
be the principal mechanism. Transient total heat flux
distributions above the M-shape pyrolysis peak for a
spreading fire were measured. Using these values, it
was shown that the upward spread rate is predictable
from a simple, one-dimensional, thermal model.