Use of Cellulose Sample for Material's Flammability and Pyrolysis Tests.
Use of Cellulose Sample for Material's Flammability and
Pyrolysis Tests.
(642 K)
Daikoku, M.; Venkatesh, S.; Saito, K.
Journal of Fire Sciences, Vol. 12, No. 5, 424-441,
September/October 1994.
Sponsor:
National Institute of Standards and Technology,
Gaithersburg, MD
Keywords:
pyrolysis; cellulose; flammability tests; polymethyl
methacrylate; thermal conductivity; cone calorimeters;
radiation absorption
Abstract:
During transient pyrolysis tests of charring and
non-charring materials, we noticed that sample
preparation is crucial to obtain reliable data, on which
theoretical models are based. Different researchers use
different sample preparation techniques which some time
causes disagreement in the results and create ambiguity
when test results are compared. In this paper, we
propose a bench mark sample preparation technique to
clarify the experimental ambiguity and establish a
reliable/common data base. Pyrolysis tests were
performed by exposing PMMA, douglas-fir particle board
(DFPB), and cellulose samples to external radiant heat
using quartz and cone heaters. The cellulose sample is
suggested for its homogeneity and combustion
characteristics similar to natural wood in order to
eliminate a variety of experimental uncertainties due to
inhomogeneity of particle board and wood samples for use
in pyrolysis tests. Temperatures were measured at the
front and back surfaces and at other intermediate
locations using fine thermocouples. Thermal
conductivity of DFPB and cellulose was then approximated
from the measured temperature distributions as the sum
of a linear temperature dependent term and a radiation
penetration effect into the porous structure in the
pre-pyrolysis zone. Effect of in-depth radiation
absorption through the surface of the PMMA samples was
estimated for various external radiant heat flux values;
and it was found that in-depth radiation is an important
factor in controlling the rate of heat transfer into the
sample.
Building and Fire Research Laboratory
National Institute of Standards and Technology
Gaithersburg, MD 20899