Reduced-Scale Ventilation-Limited Enclosure Fires: Heat and Combustion Product Measurements.
Reduced-Scale Ventilation-Limited Enclosure Fires: Heat
and Combustion Product Measurements.
(1372 K)
Johnsson, E. L.; Bundy, M. F.; Hamins, A.
Volume 1;
Interflam 2007. (Interflam '07). International
Interflam Conference, 11th Proceedings. Volume 1.
September 3-5, 2007, London, England, 415-426 pp, 2007.
Keywords:
test methods; compartment fires; ventilation; combustion
products; reduced scale; heat release rate; experiments;
temperature measurements; fire tests; soot; heat flux;
steady state; carbon monoxide; hydrocarbons; test
methods; field models
Abstract:
The National Institute of Standards and Technology
(NIST) recently conducted a series of reduced-scale
compartment fire experiments with the purpose of
generating a database of comprehensive and accurate
measurements that can be utilized both for a better
understanding of and improved modeling for compartment
fires, especially in the ventilation-limited regime. The
series of 17 experiments was conducted in a
Reduced-Scale Enclosure (RSE) with dimensions 95 cm wide
x 98 cm tall x 142 cm deep and a doorway 81 cm tall x 48
cm wide. This compartment was an approximately 2/5-scale
model of the ISO 9705 room. Single, centered burners
were used, and the fuels investigated were: natural gas,
heptane, toluene, methanol, ethanol, and polystyrene.
The liquid fuels were delivered in both pool burner and
spray burner configurations. A few half-width doorway
experiments were conducted with natural gas and heptane.
Two types of wall material were included. Four to six
target heat release rates up to 400 kW were explored
with the goal of reaching underventilated conditions.
Within the 17 experiments, 56 different combinations of
fuel, heat-release rate, and doorway width were attained
to produce steady state or generally steady periods for
which the data were statistically analyzed.The heat
release rate (HRR) was measured through oxygen-depletion
calorimetry in the exhaust hood, and the fuel flows were
also metered. Measurements of soot and gas species
(through extraction) were made at two interior locations
near the ceiling and in the exhaust hood. The gas
species measured were CO, CO2, O2, and total
hydrocarbons. Total hydrocarbons were measured with
flameionization detectors, and hydrocarbon species were
measured using gas chromatography. Gas temperatures were
measured in several interior and doorway locations with
both bare-bead and aspirated thermocouples. Doorway
velocities were estimated with an array of
bi-directional probes and pressure transducers. Heat
flux gauges and surface thermocouples on the enclosure
floor provided estimates of the thermal radiation
environment. Results obtained from these experiments,
including analysis of measurement uncertainty, are
presented and discussed. Particular attention is given
to distinctions between fires with different fuels,
including some very high temperatures (>1200DGC), heat
fluxes (>150 kW/m2), and CO concentrations (>8%).
Insights into the composition of the measured
hydrocarbons are detailed, and differences regarding
half-width and full-width doorway experiments are
described.
