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INTERNATIONAL AIRCRAFT SYSTEMS FIRE PROTECTION WORKING GROUP MEETING. AN INTEGRATED FIRE PROTECTION SYSTEM. AN INTEGRATED FIRE PROTECTION SYSTEM. BACKGROUND The concept of an Integrated Fire Protection System has been proposed by the FAA Transport Canada have commissioned a research study to:
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INTERNATIONAL AIRCRAFT SYSTEMS FIRE PROTECTION WORKING GROUP MEETING AN INTEGRATED FIRE PROTECTION SYSTEM
AN INTEGRATED FIRE PROTECTION SYSTEM BACKGROUND • The concept of an Integrated Fire Protection System has been proposed by the FAA • Transport Canada have commissioned a research study to: Identify the feasibility, practicality, and issues that are likely to result from the implementation of such a system prior to the concept being considered a cost-beneficial safety enhancement.
AN INTEGRATED FIRE PROTECTION SYSTEM WATER SYSTEM OBIGGS/ OBOGS PAX/CREW O2 SUPPLY CABIN CARGO BAYS FUEL TANKS COCKPIT/CABIN HIDDEN AREAS E/E BAYS WHEEL WELLS
AN INTEGRATED FIRE PROTECTION SYSTEM Primary areas addressed by the Study to date: • Benefit Assessment • Initial feasibility assessment of cargo compartment water mist/nitrogen system and preliminary weight assessment. • Identification of Cargo Bay Inerting system issues. • Initial feasibility assessment of a hidden areas on-demand inerting system.
INTEGRATED FIRE PROTECTIONSYSTEM BENEFIT ASSESSMENT
BENEFIT ASSESSMENT • The assessed benefit of an Integrated Fire Protection System is assessed to be in the region of: • 45 lives saved per year
INTEGRATED FIRE PROTECTIONSYSTEM CARGO COMPARTMENT INERTING SYSTEM
Cargo Compartment Inerting System • Water Mist Systems alone have not as yet been shown to meet the MPS for Cargo Bays. • However FAA testing has shown that a Water Mist system supplemented by Nitrogen can have the capability to meet the MPS
Cargo Compartment Inerting System CARGO BAY HALON REPLACEMENT WATER MIST WITH NITROGEN ENRICHED AIR
Cargo Compartment Inerting System • Using the number of Air Separation Modules (ASMs) likely to be needed for Center Fuel Tank Inerting, Cargo Bay inerting times are likely to be unacceptably long (based on NEA Flow Rate of 9.6 ft3/min and 5% Oxygen concentration). This is likely to result in excessive quantities of water being required to meet the MPS. • Hence consideration has been given to the feasibility of using additional Air Separation Modules to provide greater flow rates of Nitrogen Enriched Air.
Number of ASMs required against Centre Fuel Tank Volume (source: FAA) Cargo Compartment Inerting System • The number of Air Separation Modules needed to inert a Center Fuel Tank is almost directly related to Tank Volume Can the industry confirm the required number of ASMs for Fuel Tank Inerting for their airplanes?
Cargo Compartment Inerting System The Water Mist System used by FAA that met the MPS on the TC10 Cargo Bay was based on inerting the compartment to 10% within circa 15 minutes. The ASMs required, for a variety of aircraft, to achieve this inerting level were derived from a simplistic model developed during this study. The volumes of water required to meet the MPS were also derived from the FAA TC10 testing.
WATER MIST WITH PURE NITROGEN SUPPORTED BY NITROGEN ENRICHED AIR Cargo Compartment Inerting System WATER MIST WITH NITROGEN ENRICHED AIR CARGO BAY HALON REPLACEMENT
Cargo Compartment Inerting System Water Weight based on FAA TC10 test and scaling – was based on inerting to 10% within circa 15 minutes (although 12% inerting would probably have been sufficient) Assessment of fluid weights based on simplistic model developed as part of this study
Cargo Compartment Inerting System Note: These weights do not take into account container weights which could be high for the Nitrogen container. Data is required on the relationship between current technology container weights and gas pressure/mass.
WATER MIST WITH NITROGEN ENRICHED AIR INCREASE NO. OF ASMs, OPTIMISE ASM PERFORMANCE CARGO BAY HALON REPLACEMENT OPTIMIZATION REQUIRED FOR NITROGEN CONTAINER WEIGHT AND EFFICIENCY OF WATER MIST SYSTEM WATER MIST WITH PURE NITROGEN SUPPORTED BY NITROGEN ENRICHED AIR Cargo Compartment Inerting System
Cargo Compartment Inerting System -Issues ISSUES: • Is 12% oxygen the correct inerting level? • Flow Control in Cargo Bay to ensure that there is no flow to the cabin and no structural issues within the Cargo Bay • Model development to take account of variation in leakage rates, pressure control and NEA/Nitrogen Flow Rates
Cargo Compartment Inerting System -Issues ISSUES: • ASM performance needs to be understood better • Can Water Mist system performance be improved? - optimized nozzles, number and pitch of nozzles, dual fluid nozzles, system controlled to minimise water weight, etc • Optimisation of Water/Pure Nitrogen (or other extinguishing agent) concentrations
Cargo Compartment Inerting System -Issues ISSUES: • Depletion of oxygen due to the fire and absorption by the water needs to be better understood • Water Additives for improved fire suppression, anti-freeze, etc taking into consideration the potential side effects especially when used for the Cabin Water Mist system.
INTEGRATED FIRE PROTECTIONSYSTEM HIDDEN AREA FIRE SUPPRESSION
HIDDEN AREA FIRE SUPPRESSION • Feasibility of OBIGGS generated NEA to inert hidden areas in the overhead area
90% of hidden fires could be accommodated if the hidden area was inerted within 8 minutes HIDDEN AREA FIRE SUPPRESSION • The time for a hidden fire to become non-survivable
HIDDEN AREA FIRE SUPPRESSION • Based on the aircraft studied to date it would appear that a significant proportion of the hidden areas could be inerted within 8 minutes to oxygen concentrations of 12% using only the Air Separation Modules needed for Center Fuel Tank Inerting.
HIDDEN AREA FIRE SUPPRESSION • Only the volume of the hidden area in close proximity to the fire requires inerting • Use the number of ASMs currently fitted to aircraft for CWT inerting to inert portions of the hidden areas to 12% O2 within 8 minutes
HIDDEN AREA FIRE SUPPRESSION • It is theoretically feasible to use the ASMs currently installed on aircraft for CWT inerting for hidden area inerting