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11-05-03IASFPWG – Atlantic City, NJ Limiting Oxygen Concentration (LOC) Work Update International Aircraft Systems Fire Protection Working Group Atlantic City, NJ November 5 - 6, 2003 Steve Summer Project Engineer Federal Aviation Administration Fire Safety Branch, AAR-440
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11-05-03IASFPWG – Atlantic City, NJ LOC Testing – Work Update Technical Note consisting of all data except 400 cycle short tests published and placed on website (AR-02/79) 400 cycle short spark energy has been measured and testing has been completed Final report currently being put together
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11-05-03IASFPWG – Atlantic City, NJ Facilities – Pressure Chamber
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11-05-03IASFPWG – Atlantic City, NJ Facilities – Pressure Chamber 353 ft 3 pressure vessel Working pressure of 650 psi. Attached vacuum pump used to evacuate chamber to reduced pressures seen at altitude. Not capable of simulating temperatures seen at altitude.
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11-05-03IASFPWG – Atlantic City, NJ Facilities - LOC Test Article 9 ft 3 simulated fuel tank placed inside of vessel equipped with: Bottom surface heaters. 12 thermocouples. 2 piezoresistive pressure transducers mounted behind sintered porous metal discs. Interchangeable pressure relief mechanism. ¼-in. aluminum plate. Foil diaphragm. Spark gap. 2 tungsten electrodes with controllable gap alignment and spacing
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11-05-03IASFPWG – Atlantic City, NJ Apparatus – LOC Testing
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11-05-03IASFPWG – Atlantic City, NJ Apparatus – LOC Testing
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11-05-03IASFPWG – Atlantic City, NJ Ullage Vapor Sampling
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11-05-03IASFPWG – Atlantic City, NJ LOC Testing Apparatus Ignition Sources 10 kV Oil burner transformer operating at ~30 mA provided both long (~1 second) and short (~0.1 second) arcs J-57 Engine spark igniter provided a very short (~175 second) spark 3" x 6" x 1" metal block heated by two cartridge heaters to temperature in excess of 1400°F 400 cycle, 120 V hard short to ground provided high energy/current, short duration spark Energy Measurements Voltage and current traces were taken using a HV and current probe at the spark gap connected to oscilloscope
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11-05-03IASFPWG – Atlantic City, NJ Test Program JP-8 LOC Tests Mass Loading ~ 4.5 kg/m 3 Ambient pressure corresponding to altitudes of 0, 10, 20, 30 and 38 kft Ullage oxygen concentrations ranging from 21% to below the determined LOC Tests conducted with two different pressure relief mechanisms ¼-in. aluminum plate – Ignition = movement of plate Foil diaphragm –Ignition = rupture of foil
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11-05-03IASFPWG – Atlantic City, NJ Test Program (cont.) Tests conducted initially at all altitudes with long duration oil burner transformer arc (~0.5 J, 1 s) Subsequent tests conducted with various ignition sources at sea level in effort to determine any variation of LOC with ignition source Short duration oil burner transformer arc (~0.08 J, 0.1 s) J-57 Engine igniter spark (~0.5 J, 175 s) Hot surface vapor ignition (HSVI) 400 cycle, 120 V hard short to ground
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11-05-03IASFPWG – Atlantic City, NJ
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11-05-03IASFPWG – Atlantic City, NJ 400 Cycle Hard Short Tests
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11-05-03IASFPWG – Atlantic City, NJ Spark Energy Measurements Energy ~ 2.2 J Duration ~.006 s Energy ~ 2.8 J Duration ~.01 s Energy ~ 1.75 J Duration ~.01 s
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11-05-03IASFPWG – Atlantic City, NJ 400 Cycle Short Test Results
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11-05-03IASFPWG – Atlantic City, NJ Summary ~2 J spark from 400 cycle short did not cause a change in the LOC at sea level Of all ignition sources used (oil burner arc, engine ignitor spark, hot surface, 400 cycle short), none have caused an ignition with ullage above 12% O 2 Testing is complete and final report will be published and available on website ASAP
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