- Author
-
Gottuk, D. T.
|
Roby, R. J.
|
Beyler, C. L.
- Title
- Study of Carbon Monoxide and Smoke Yields From Compartment Fires With External Burning.
- Coporate
- Virginia Polytechnic Institute and State Univ., Blacksburg
Hughes Associates, Inc., Columbia, MD
- Sponsor
- National Institute of Standards and Technology, Gaithersburg, MD
- Contract
- NIST-GRANT-60NANB8D0928
- Book or Conf
- Combustion Institute, Symposium (International) on Combustion, 24th. July 5-10, 1992,
Combustion Institute, Pittsburgh, PA,
Sydney, Australia,
1729-1735 p.,
1992
- Keywords
-
combustion
|
carbon monoxide
|
smoke yield
|
compartment fires
|
combustion
- Abstract
- Hexane fires were burned in a 2.2 m³ compartment with a window-style exhaust vent to study the effects of external burning on carbon monoxide and smoke yields downstream of a fire compartment. External burning was observed to occur in several modes: 1) intermittent flashes, 2) bursts that lasted for only a few seconds and 3) sustained external burning. Results showed that the flammability of the compartment fire effluent was a function of the equivalence ratio and that distinguishable equivalence ratios exist that determined which mode of external burning can be obtained for a given compartment fire. Results also showed that the reduction of carbon monoxide and smoke only occurred in the presence of sustained external burning. At plume equivalence ratios above 1.7, sustained external burning always occurred and the downstream carbon monoxide yield was reduced to 10 to 25 percent of the upper layer yield and the downstream smoke yield was reduced to approximately 0 to 50 percent of the level observed prior to sustained external burning. For fires with no sustained external burning, carbon monoxide yields downstream of the compartment fire were the same as upper layer yields even when flashes or short bursts of external burning occurred. Beyler's ignition criterion for layer burning was applied to the mixing of the hot fuel-rich, upper layer gases and ambient air outside of the fire compartment. The results suggest that the ignition index predicts the potential for external burning at equivalence ratios of 1.2 and grater. However, the occurrence of external burning is dependent on the presence of an ignition source which is dictated by the vent geometry and fire size.