Transport and Oxidation of Compartment Fire Exhaust Gases in an Adjacent Corridor.
Transport and Oxidation of Compartment Fire Exhaust
Gases in an Adjacent Corridor.
(1307 K)
Lattimer, B. Y.; Ewens, D. S.; Vandsburger, U.; Roby, R.
J.
Journal of Fire Protection Engineering, Vol. 6, No. 4,
163-181, 1994.
Sponsor:
National Institute of Standards and Technology,
Gaithersburg, MD
Keywords:
corridors; compartment fires; exhaust gases; oxidation;
flame length; carbon monoxide; hydrocarbons; global
equivalence ratio; soffits
Abstract:
The oxidation of underventilated compartment fire
exhaust gases during their transport down a corridor
adjacent to the compartment was experimentally
investigated. External burning from a compartment has
been reported to decrease the toxic exhaust gas levels
downstream of the compartment. The focus of the
investigation was to identify the phenomena controlling
the oxidation of the combustion gases external of the
compartment as they traveled down a corridor during
external burning. Variables in the research included
the fire size, the hallway inlet and exit soffit
heights, and the vent area from which the exhaust gases
exit the compartment. Through gas sampling both in the
hallway and in the exhaust duct downstream of the
hallway, the oxidation of carbon monoxide (CO) and total
unburned hydrocarbons (UHC) was studied. The
concentrations of CO and UHC were reduced from the
entrance to the exit of the hallway by 65 percent and 98
percent, respectively, with no soffit at either end of
the hallway. The addition of a 20 cm soffit at the
hallway entrance dramatically improved the oxidation and
dilution of CO and UHC, resulting in a reduction of 80
percent and 94 percent in CO and UHC concentrations;
respectively, from the entrance to the exit of the
hallway. A soffit at the hallway exit was found to
inhibit the species oxidation and resulted in only a 51
percent and 94 percent reduction in CO and UHC
concentrations, respectively, from the exit to the
entrance of the hallway. Descriptions of the types of
external burning which occurred for different soffit
geometries are given and then related to how it affected
the oxidation of the exhaust gases within the hallway.
The global equivalence ratio (GER) in the compartment
could not predict the post-hallway species yields, so
correlations were developed to predict the CO and UHC
yields downstream of the hallway using dimensionless
groups derived from dimensional analysis.
Building and Fire Research Laboratory
National Institute of Standards and Technology
Gaithersburg, MD 20899