New Smoke Concentration Meter. ABSTRACT ONLY.
New Smoke Concentration Meter. ABSTRACT ONLY.
(84 K)
Mulholland, G. W.; Johnsson, E. L.
International Conference on Fire Research and
Engineering (ICFRE3), Third (3rd). Proceedings. Program
and Abstracts. Society of Fire Protection Engineers
(SFPE), National Institute of Standards and Technology
(NIST) and International Association of Fire Safety
Science (IAFSS). October 4-8, 1999, Chicago, IL,
Society of Fire Protection Engineers, Boston, MA, 1-1
pp, 1999.
Keywords:
fire research; fire protection engineering; smoke meters
Abstract:
All fires produce smoke, and that smoke can be
beneficial (as in triggering a smoke detector) or
harmful (as in impeding escape). Therefore, it is
critical that one knows how much smoke a burning object
produces and where that smoke is moving relative to
people or fire sensors. A new smoke meter is designed
to measure the smoke production on a mass basis by an
optical method rather than requiring tedious filter
collection and weighing of the smoke produced. The key
to this new instrument is the discovery that the
specific extinction coefficient is nearly universal for
overventilated flaming combustion with a value of 8.7
m2/g + 1.1 m2/g with only a modest dependence on fire
size, fuel, and flame condition. This finding enables
the measurement of the mass concentration of smoke from
the transmission of light through the smoke via the
formula [see report] where L is the path length through
the smoke and Io, and I refer to the incident and
transmitted light intensity for a monochromatic light
source. This finding will obviate the more cumbersome
mass extraction methods and offer the potential for both
time- and space-resolved determinations. The key design
features of the new smoke meter will be presented. The
detailed design, which is almost entirely based on
commercially available components, is available from a
NIST report. An extensive series of tests involving
propane tires at 50 kW, 200 kW, and 450 kW and heptane
and toluene pool fires at about 250 kW were carried out
to assess the uncertainty in the measurement method.
The results of the uncertainty assessment will be
discussed along with the range of application of the new
smoke meter. A specific example will be presented
illustrating how the mass concentration of smoke, the
rate of smoke production, and the yield of smoke are
determined using the new instrument.
