Citation

Haussmann GJ, Matta LM. J. Appl. Fire Sci. 2002; 11(4): 335-348.

Affiliation

Exponent Failure Analysis Associates, Houston, TX 77099, United States

Copyright

(Copyright © 2002, Baywood Publishing)

DOI

unavailable

PMID

unavailable

Abstract

Gasoline spills during the refueling of a hot engine creates a fire hazard. A unique hot surface ignition mechanism has been discovered involving exhaust systems on hot, shut down engines. The present research involves small engines up to 45 hp that operate at relatively high tailpipe temperatures. Although exhaust temperatures in excess of 700 deg C were common, external surfaces were found to be incapable of causing ignition for the conditions studied. After engine shutdown, however, a buoyancy-driven flow pattern was discovered in which gases enter the exhaust pipe. Heating of flammable vapors drawn into the exhaust pipe resulted in ignition, even though ignition was not possible on external surfaces. This ignition mechanism exists when the tailpipe discharges upward or horizontally, but was not observed in downward facing configurations. For ignition to occur by this mechanism, an exhaust diameter of 3.8 cm or greater and a temperature of 550 deg C were required.

Language: en