Size Distribution and Light Scattering Properties of Test Smokes.
Size Distribution and Light Scattering Properties of
Test Smokes.
(360 K)
Weinert, D. W.; Cleary, T. G.; Mulholland, G. W.
NIST SP 965; February 2001.
International Conference on Automatic Fire Detection
"AUBE '01", 12th. Proceedings. National Institute of
Standards and Technology. March 25-28, 2001,
Gaithersburg, MD, Beall, K.; Grosshandler, W. L.; Luck,
H., Editor(s)(s), 58-70 pp, 2001.
Keywords:
fire detection; fire detection systems; smoke detectors;
smoke generation; size distribution; sampling; light
scattering
Abstract:
Measurements of particles size distributions and optical
properties of smoke detector test smokes may yield a
better understanding of existing detector designs and
facilitate design improvements; NIST is making such
measurements now on smokes produced in the fire
emulator/detector evaluator (FE/DE). Results are
presented for the first time of the mass scattering
cross section (m2.g-1) of one flame generated
(propylene) and two non-flaming fire generated tests
smokes (cotton smolder, wood pyrolysis). Size
characterization shows that the smoke from pyrolysed
wood blocks is a unimodal distribution with a MMAD of
1.55 mm, while the smoldered cotton wick fuel has a
bimodal distribution with a MMAD of 0.31 mm for its
measurable mode. It was found that 48D% of the mass of
the cotton wick smoke was below 0.056 mm. The ratio of
polarization and the degree of linear polarization have
been demonstrated as a means of distinguishing between
soot from flaming fires and smoke particles from
non-flaming fires. The ratio of polarization is shown to
be more sensitive than the degree of polarization to
soots from different flaming fuels. Three flame
generated smokes (acetylene, ethylene and propylene) are
shown to have similar q-plots, which are easily
distinguished from the q- plots for the non-flaming
fuels smokes.
Building and Fire Research Laboratory
National Institute of Standards and Technology
Gaithersburg, MD 20899