- Author
- Summer, S. M.
- Title
- Limiting Oxygen Concentration Required to Inert Jet Fuel Vapors Existing at Reduced Fuel Tank Pressures.
- Coporate
- Federal Aviation Administration, Atlantic City International Airport, NJ
- Sponsor
- Department of Transportation, Washington, DC
- Report
- DOT/FAA/AR-TN02/79, August 2003, 31 p.
- Distribution
- FOR MORE INFORMATION CONTACT: Federal Aviation Administration, William J. Hughes Technical Center's full-text technical reports page. Website: http://www.fire.tc.faa.gov/
- Keywords
- fuel tanks | oxygen concentration | jet fuels | fuel vapors | flammability | ignition | JP-1 jet fuel | JP-8 jet fuel | inerting | nitrogen | aircraft fuel tanks | pressure | experiments | aircraft fuels | validation
- Identifiers
- aviation fuel specification and characteristics; spark/arc energy calculation method and results; methane validation tests; long duration oil burner transformer tests; engine spark igniter tests; short duration oil burner transformer tests; hot surface vapor ignition tests; commercial and military aviation fuel specifications
- Abstract
- This report discusses experiments to determine the reduction in oxygen concentration required to prevent a fuel tank explosion. A simulated aircraft fuel tank containing JP-8 fuel of an amount equivalent to a mass loading of approximately 4.5 kg/m3 was used to determine the limiting oxygen concentration (LOC) at pressures corresponding to altitudes ranging from 0 to 38 kft. In addition, the peak pressure rise was measured at various altitudes (pressures) due to ignition occurring at O2 levels approximately 1% to 1.5% above the LOC. A wide range of ignition sources were used throughout the testing. An oil burner transformer connected to an analog timer provided a low power arc of both short (0.1 second) and long durations (1 second), a spark igniter taken from a J-57 engine provided a very short duration (175 seconds) high powered spark, and a heated metal block was used as a hot surface ignition source. These varied capabilities allowed for an evaluation of the variation in the LOC due to a specific type of ignition source. From these tests, it was determined that the LOC at sea level through 10 kft is approximately 12% O2, while exhibiting a linear increase from 12% at 10 kft to approximately 14.5% at 40 kft. Tests with various sparks/arcs as ignition sources at sea level showed little variation in results, with the LOC ranging from 12.0% to 12.8%. Also, a heated surface capable of igniting a fuel air mixture proved insufficient for ignition in a tank inerted to just 14%. Peak pressures resulting from ignition at oxygen concentrations 1% to 1.5% above LOC values decreased as the altitude was increased to 30 kft, while the duration to reach the peak pressure increased.