Material Flammability Test Assessment for Space Station Freedom.
Material Flammability Test Assessment for Space Station
Freedom.
(2501 K)
Ohlemiller, T. J.; Villa, K. M.
NISTIR 4591; NASA CR-187115; 78 p. June 1991.
Sponsor:
National Aeronautics and Space Administration, Lewis
Research Center, Cleveland, OH
Available from:
National Technical Information Service
Order number: PB91-216606
Keywords:
flame spread; flammability; ignition; microgravity; heat
release rate; test methods; spacecraft; small scale fire
tests; lexan (trademark)
Abstract:
The NASA Upward Flame Propagation test, which measures
response to a well-defined laminar flame at the bottom
of a test sample, is currently used to screen for
flammability all materials intended for use in the
interior of manned spacecraft. The response of a series
of materials was compared in this test and in the
standard NIST Flammability Tests (Cone Calorimeter for
rate of heat release and LIFT tests for ignitability and
lateral flame spread). The goal was to see if these
differing flammability assessment approaches provide
comparable information on the potential hazards of a
material. In the first phase of this study only one of
the samples exhibited appreciable flame spread in the
NASA test, yielding very limited data for comparisons
with the NIST test results. The NIST tests, which
employ a variable external radiant flux as an additional
test parameter, revealed a widely varying response to
this flux. In the second phase of the study, the NASA
test was modified to include radiative pre-heating of
the samples before they were exposed to the standard
NASA ignitier in the standard manner. The response of
the materials, as measured by the minimum pre-heat flux
(or temperature) to yield upward spread, varied widely;
for example, Nomex required very little pre-heating to
yield full-length spread whereas Lexan 9034 was
resistant. Rate of heat release behavior or lateral
flame spread behavior alone did not appear to be
predictive of behavior in the modified NASA test. A
simplified upward flame spread model, which utilizes
inputs derived from the NIST test, was employed in an
attempt to predict the behavior in the modified NASA
tests. The model greatly under-predicted the necessary
pre-heat flux for some materials while doing the
opposite for other materials. Thus, at the present, a
firm relation between the behavior in the NASA test and
in the NIST tests has not been established.
Building and Fire Research Laboratory
National Institute of Standards and Technology
Gaithersburg, MD 20899