feasibility of using nitrogen administration enriched air for fire … · 2007. 11. 7. ·...
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Federal AviationAdministrationFeasibility of Using Nitrogen
Enriched Air for Fire Protection in Inaccessible Areas in Aircraft
Presented to: The Fifth Triennial International Fire and Cabin Safety Research Conference
Atlantic City, NJ
Steven Summer
David Blake
FAA William J. Hughes Technical Center
October 31, 2007
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Feasibility of Using Nitrogen Enriched Air for Fire Protection in Inaccessible Areas in AircraftOctober 31, 2007
Background
• The FAA recently has released an NPRM requiring the reduction of flammability within heated fuel tanks (affecting over 3,200 in service aircraft)
• The most likely method of conformance is the utilization of an On Board Inert Gas Generating System (OBIGGS)
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Feasibility of Using Nitrogen Enriched Air for Fire Protection in Inaccessible Areas in AircraftOctober 31, 2007
CUMULATIVE PROBABILITY DISTRIBUTION OF TIME TO BECOME NON-SURVIVABLE
0.000.100.200.300.400.500.600.700.800.901.00
0 10 20 30 40 50 60TIME MINUTES 1705 Fina l R e por t a nd Da ta Ste p 2 . 2 T ime NS
CU
MU
LATI
VE P
RO
BA
BIL
ITY
Background• CAA Paper 2002/01 (FAA Reference DOT/FAA/AR-
02/50) determined that 90% of non-survivable hidden area fires could be prevented if extinguished within 8 minutes
• 90% of hidden fires could be accommodated if the hidden area was inerted within 8 minutes
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Feasibility of Using Nitrogen Enriched Air for Fire Protection in Inaccessible Areas in AircraftOctober 31, 2007
Background• With inerting systems now/soon to be on board, an integrated fire
protection system to provide protection for these hidden areas may be feasible
• Such a system would provide enhanced fire protection while utilizing a system already installed, thus saving on cost, weight and space on board the aircraft
PAX/CREWO2 SUPPLY
WATERSYSTEM
FUELTANKS
CARGOBAYSCABIN WHEEL
WELLSE/E BAYSINACCESSIBLEAREAS
OBIGGS/OBOGS
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Feasibility of Using Nitrogen Enriched Air for Fire Protection in Inaccessible Areas in AircraftOctober 31, 2007
OBJECTIVES
• Design and install an NEA distribution system for fire protection of the overhead area of the FAAs 747SP, 727 and 737 test articles
• Examine the effectiveness of OBIGGS to extinguish fires existing in overhead areas
• Examine the effect of various conditions on the ability of the OBIGGS to successfully protect the overhead area:
• Bleed air pressure• OBIGGS feed pressure• OBIGGS back pressure• Permeate pressure (altitude)• Ventilation• Etc.
• Future work may include expanding the OBIGGS system to other hidden areas aboard the aircraft (E/E bays, wheel wells, etc.)
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Feasibility of Using Nitrogen Enriched Air for Fire Protection in Inaccessible Areas in AircraftOctober 31, 2007
Material Limiting Oxygen Index Polyurethane Foam 16.5
Polyethylene 17.4 Epoxy resin 19.8
Phenolic resin 21 Nylon 25
Neoprene 40 Polycarbonate (Lexan) 27
Cardboard 24.7
Limiting Oxygen Index Data
Theoretical minimum oxygen concentrations to sustain combustion of solid fuels are in the range of 12.5% to 13.5%.
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Feasibility of Using Nitrogen Enriched Air for Fire Protection in Inaccessible Areas in AircraftOctober 31, 2007
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Feasibility of Using Nitrogen Enriched Air for Fire Protection in Inaccessible Areas in AircraftOctober 31, 2007
NEA Source
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Feasibility of Using Nitrogen Enriched Air for Fire Protection in Inaccessible Areas in AircraftOctober 31, 2007
NEA (blue) and vacuum (red) lines attached to 727 fuselage
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Feasibility of Using Nitrogen Enriched Air for Fire Protection in Inaccessible Areas in AircraftOctober 31, 2007
727 Interior cabin ceiling mockup
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Feasibility of Using Nitrogen Enriched Air for Fire Protection in Inaccessible Areas in AircraftOctober 31, 2007
727 Instrumentation in area of cabin ceiling mockup
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Feasibility of Using Nitrogen Enriched Air for Fire Protection in Inaccessible Areas in AircraftOctober 31, 2007
• 747SP equipped with OBIGGS installed in the empty pack bay utilizing up to 6 ASMs
• 737 aircraft in process of being equipped with a single ASM OBIGGS
• Instrumentation allowing for monitoring of oxygen at 12 locations in overhead area of each aircraft
• NEA flow and purity also measured as well as various system pressures
737 & 747SP TEST ARTICLES
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Feasibility of Using Nitrogen Enriched Air for Fire Protection in Inaccessible Areas in AircraftOctober 31, 2007
TEST CONFIGURATION – 747SP
Current Test Section (STA 1241)
From OBIGGS
Vacuum Source
From OBIGGS
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Feasibility of Using Nitrogen Enriched Air for Fire Protection in Inaccessible Areas in AircraftOctober 31, 2007
TEST SECTION – 747SP
• Located at approximately STA 1241
• Approximately 20 ft. wide, 5 ft. tall at center
• Cross-sectional area of approximately 42 ft2
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Feasibility of Using Nitrogen Enriched Air for Fire Protection in Inaccessible Areas in AircraftOctober 31, 2007
TEST CONFIGURATION – 737
Current Test Section
From OBIGGS
From OBIGGS`
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Feasibility of Using Nitrogen Enriched Air for Fire Protection in Inaccessible Areas in AircraftOctober 31, 2007
TEST SECTION – 737
• Approximately 9 ft. wide, 10 in. tall at center
• Cross-sectional area of approximately 3 ft2
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Feasibility of Using Nitrogen Enriched Air for Fire Protection in Inaccessible Areas in AircraftOctober 31, 2007
Planned Activities
•Determine flow rate and oxygen concentration of NEA needed to inert the attic space in a narrow body fuselage.
•Preliminary testing on 747SP with a single NEA deposit location has confirmed the need for a vacuum source (or other method) to control the spread of NEA
•OBIGGS and test instrumentation build up on 737 is underway