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Summary
Forty percent of
the passengers who survive the impact of an aircraft accident
subsequently die in a postcrash fire. Unless this percentage
is reduced or the accident rate decreases, the number of fire
fatalities will increase by four percent each year with the expected
growth in passenger air traffic. Compounding the upward trend
in aircraft fire fatalities is the additional fire load associated
with the one percent annual growth in the use of lightweight,
combustible polymers and composites for aircraft interiors and
structures. Current aircraft utilize several tons of combustible
plastics for cabin interior components - a fire load comparable
to the equivalent weight of aviation fuel. The cabin fire load
will approximately double in the very large (800 passenger) airplanes
under development by airframe manufacturers unless ultra fire-resistant
materials become available.
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The use of
materials with improved fire resistance (relative to commodity
plastics) was mandated by the FAA in 1987 with requirements for
the burning rate and flame spread of seat cushions, and in 1990
with the establishment of regulations limiting the heat release
rate of large area cabin interior components. These regulations
provide an additional 2-4 minutes of cabin escape time in the
event of an aircraft accident involving a post crash fuel fire
outside the cabin. Further improvement in cabin material fire-safety
is unlikely without government-sponsored research because the
market is limited to passenger aircraft cabins and does not justify
the research investment by private industry. In response to this
situation the FAA has initiated a proactive, long range research
effort in Fire Resistant Materials to identify and develop the
enabling materials technology for a cost-effective, fireproof
passenger aircraft cabin. In combination with other fire-safety
system improvements, ultra-fire-resistant materials will eliminate
catastrophic inflight fuselage fires and provide a minimum of
10 minutes of passenger escape time in a postcrash fire.
The objective of
the Fire Resistant Materials program is to eliminate burning
cabin materials as a cause of death in aircraft accidents. Research
is basic in nature and focuses on the synthesis, modeling, processing,
and characterization of new materials and materials combinations.
In accord with the recommendations of the National Research Council¹s
Materials Advisory Board in their report ³Fire- and Smoke-Resistant
Interior Materials for Commercial Transport Aircraft,² (NMAB-477-1,
National Academy Press, 1995) near term technical approaches
include modification of specialty and commodity polymers using
additives and processing routes. Databasing of materials fire
performance in micro-, bench-, and full-scale testing supports
science-based studies of polymer combustion and identifies critical
fire performance properties to guide development. Long term activities
include the synthesis of new, thermally stable, low fuel value
organic/inorganic polymer systems. The synthesis effort is supported
by fundamental research to understand polymer combustion and
fire resistance mechanisms using numerical and analytic modeling
and the development of new characterization techniques.
The output of this
research will be an order-of-magnitude reduction in cabin fire
hazard relative to current cabin materials at comparable cost
and functionality. Since the heat release rate of burning materials
is the primary fire hazard indicator, the technical objective
is to develop low-cost, lightweight, serviceable polymers and
composite materials with zero heat release rate as measured by
FAR 25.853(a-1), "Heat Release Rate Test for Cabin Materials."
Materials with a zero heat release rate will provide sufficient
passenger escape time in a post crash fuel fire to ensure survivability.
With respect to the 1996 baseline for new aircraft, individual
fire-resistant materials will demonstrate a 50% reduction in
heat release rate by the year 2002. Prototype cabin components
fabricated from combinations of fire-resistant materials will
demonstrate zero heat release rate by the year 2010. The potentially
higher initial cost of fire-resistant cabin materials will be
offset by user financial incentives which include shorter process
cycles, better durability, and lower heat release rate.
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The fire-resistant
materials program is executed from an in-house technology base
at the W.J. Hughes Technical Center, Atlantic City Airport, NJ,
through FAA-industry partnerships and university-based research
consortia. Direct funding by several Fortune 100 aircraft and
chemical companies to FAA-university-industry consortia covers
about 30% of research costs for fire safe materials. During the
first two years of the program (1995-1996) we have made significant
progress in achieving our interim goal of a 50% reduction in
the heat release rate of cabin materials by 2002 and zero heat
release rate cabin materials by 2010. The progress to date in
this program reflects the commitment of the Congress, the FAA,
and the materials and aircraft industries to improving the safety
of air transportation. This collaboration has resulted in the
outstanding technical work which is sumarized in this report.
The FAA is grateful to all of the participating researchers in
government, industry, and academia whose ideas and hard work
are creating the enabling technology for a fireproof passenger
aircraft cabin.
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