Post on 15-May-2015
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Consumer Product Safety Commission Meeting
Rockville, MD, April 25, 2013
Federal AviationAdministration
Richard E. Lyon
Manager, FAA Fire Research
William J. Hughes Technical Center
Atlantic City International Airport, NJ
Development of a Fire Test for Aircraft Seat
Cushions
2Federal AviationAdministration
Development of FAA Fire Test for Seat CushionsCPSC Meeting, April 25, 2013
Development of a Fire Test for Aircraft Seat Cushions
• Result of fatal post-crash fires.
• Work performed in early 1980s at new full scale test facility at FAA Tech Center.
• Rule implemented 1984-1987 required retrofit of 650,000 aircraft seats with fire blocking layers.
• First fire regulation that went beyond a simple Bunsen burner test (i.e., FR foam).
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Development of FAA Fire Test for Seat CushionsCPSC Meeting, April 25, 2013
Example of Post-Crash Fire
DC10, JFK, 1976, bird strike
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Development of FAA Fire Test for Seat CushionsCPSC Meeting, April 25, 2013
Example of a Post-Crash Fire
DC10, LAX, 1978, tire failure
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Development of FAA Fire Test for Seat CushionsCPSC Meeting, April 25, 2013
Post-Crash Fire Simulation in Full Scale Indoor Fire Test Facility at FAA
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Development of FAA Fire Test for Seat CushionsCPSC Meeting, April 25, 2013
Full Scale Cabin Mockup
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Development of FAA Fire Test for Seat CushionsCPSC Meeting, April 25, 2013
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Development of FAA Fire Test for Seat CushionsCPSC Meeting, April 25, 2013
Ignition Source by Fire Scenario
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Development of FAA Fire Test for Seat CushionsCPSC Meeting, April 25, 2013
For Small Ignition Source > Cigarette,FR Foam Alone was Ineffective
No Blocker
FR Foam
Foam Fire Blocker Fabric Fire Blocker
Seat Cushion Construction
FR Foam PU Foam PU FoamFR Foam
For Fire Blocked Seats FR Foam was Unnecessary
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Development of FAA Fire Test for Seat CushionsCPSC Meeting, April 25, 2013
StandardNFR Seating
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Development of FAA Fire Test for Seat CushionsCPSC Meeting, April 25, 2013
No Fire Blocker Fire Blocker
Effectiveness of Fire Blocking Layerat 2 minutes into test
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Development of FAA Fire Test for Seat CushionsCPSC Meeting, April 25, 2013
Q(W ) dH
dt q A(t) q L2(t) q (L0 v t)2
Heat releaserate (W/m2)
Burning Area, A = L2
Flame spread velocity
Release rate of energy and combustion
products
Cumulative Fire Hazard
H q (L0 v)2d0
t
t exp t 2
Q0 = Initial combustion rate
(v0/L0)2 = (Initial flame spread rate)2
Initial heated length, L0
Regulation addresses these 2 fire response
parameters
Simple Compartment Fire Growth Model
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Development of FAA Fire Test for Seat CushionsCPSC Meeting, April 25, 2013
Fire-blocking Foams or Fabrics Provide an Additional Minute of Escape Time in a Post Crash Fire
0
0.2
0.4
0.6
0.8
1
0 50 100 150 200 250
Unprotected Cushion
Fabric Fire Blocking Layer
Foam Fire Blocking Layer
Noncombustible FoamF
ract
iona
l Eff
ectiv
e D
ose
Elapsed Time, Seconds
+ 1 minuteOriginal Escape Time
Full scale test data
Fire growth model(best fit)
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Development of FAA Fire Test for Seat CushionsCPSC Meeting, April 25, 2013
10-5
10-4
10-3
160 180 200 220 240 260Bes
t F
it C
abin
Fir
e M
od
el P
aram
eter
s
Cabin Escape Time, seconds
Combustion (mass loss) rate parameter,
Surface flame spread parameter,
Escape Time in a Post Crash Fire is Very Sensitive to Combustion (Mass Loss) Rate Parameter
…. Because cover fabric is similar for all tests
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Development of FAA Fire Test for Seat CushionsCPSC Meeting, April 25, 2013
Development of a Laboratory Test for Aircraft Seat Cushions
Welded Steel Test Frame on Load Cell 2-min Exposure to Oil Burner
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Development of FAA Fire Test for Seat CushionsCPSC Meeting, April 25, 2013
Examples of Residential Oil
Burners
The FAA used modified
home heating oil burners
to simulate the effects of a
post-crash fire on aircraft
seating in a laboratory
(controlled) test
Lennox OB-32
Carlin 200 CRD
Park DPL 3400
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Development of FAA Fire Test for Seat CushionsCPSC Meeting, April 25, 2013
Test Specimens• A sample set consists of
– one seat bottom (horizontal)• 18” x 20” x 4”
– one seat back (vertical)• 18” x 25” x 2”
• A minimum of 3 sample sets will be tested• Each specimen will be constructed of the
principal components and assembly of the production seat cushion
– Foam core– Flotation material– Fire block material– Dress covering– Seams
• Weakest point of cushion will be exposed directly to burner flame
• Specimens will be conditioned for a minimum of 24 hours before testing.
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Development of FAA Fire Test for Seat CushionsCPSC Meeting, April 25, 2013
Specimen Frame
• Frame constructed of 1”x1”x1/8” angle steel
• Back and bottom support straps constructed of 1”x1/8” steel flat stock
• Frame is welded together
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Development of FAA Fire Test for Seat CushionsCPSC Meeting, April 25, 2013
Test Procedure• Record weight of each component (back and bottom
cushion) to the nearest 0.02 pound.
• Align seat frame with cushion according to Chapter 7
• Position seat away from burner flame, fire burner for 2 minutes to warm up
• Position the seat in front of burner flame at 2 minutes and expose for an additional 2 minutes, then turn off the burner
• The test is over when the seat cushion has self extinguished OR after 5 minutes from burner shut-off
• Record the final weight at test termination and extinguish gently if necessary
• Measure burn lengths on top, bottom, back and front of each component
• A sample set of 3 tests will be run for each cushion configuration
• A wire may be used to restrain the back cushion to the frame as long as the wire does not impede or redirect the flame
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Development of FAA Fire Test for Seat CushionsCPSC Meeting, April 25, 2013
Burner Alignment
Top View
Front View
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Development of FAA Fire Test for Seat CushionsCPSC Meeting, April 25, 2013
Test Criteria
The average burn length may not exceed 17 inches in any direction, and 2 out of the 3
samples tested must not exceed 17 inches
minitial mfinal minitial
100 < 10%
Burn Length < 17 inches
• The mass loss is measured for each test.
• The average mass loss of the 3 tests run can not exceed 10% of the starting weight.
• 2/3 of tests < 10% BurnerBurner
Limit Combustibles
Limit Flame Spread
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Development of FAA Fire Test for Seat CushionsCPSC Meeting, April 25, 2013
Current Methods of Meeting FAA Flammability Requirement
• Expandable graphite• Melamine• Polychloroprene• Etc.
Non-woven felts w/ scrim• Aramid fiber• PBI fiber• Panox fiber• Phenolic fiber
Combustion Modified FoamFR Foam w/ Fire Blocking
Layer
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Development of FAA Fire Test for Seat CushionsCPSC Meeting, April 25, 2013
Inter-laboratory Study (6 labs x 3 seats)
CriterionBurn Length(flame spread)
Mass Loss(Combustibles)
Repeatability(Average within-lab variation)
Reproducibility(Average between-lab variation)
14% 13%
8% 7%
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Development of FAA Fire Test for Seat CushionsCPSC Meeting, April 25, 2013
Advisory Material: Seat Cushion Test
• AC 25.853-1 - Flammability Requirements for Aircraft Seat Cushions
• Gives advice on test conduct, sample preparation, burner calibration, etc.
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Development of FAA Fire Test for Seat CushionsCPSC Meeting, April 25, 2013
*Fire Test Handbook, DOT/FAA/AR-00/12April 2000
• This test method evaluates the burn resistance and weight loss characteristics of aircraft seat cushions when exposed to a high-intensity open flame to show compliance to the requirements of FAR 25.853.
• Test Parameters:– Burn Length– % Mass Loss
*companion document to FAR 25.853, Appendix F
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Development of FAA Fire Test for Seat CushionsCPSC Meeting, April 25, 2013
Recent Work at FAA to Standardize Oil Burner
Sonic Nozzle @ 2.0 gal/hour
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Development of FAA Fire Test for Seat CushionsCPSC Meeting, April 25, 2013
NexGen Burner Design
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FAA Oil Burner Test for Seat CushionsACO Seminar, April 2013
Comparison of Sonic Vs. Park BurnerSeat Burner Comparison
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A irFlex Fireblock Dax
Cushion Type
We
igh
t L
os
s P
erc
en
tag
e
Park
Sonic 0¡ Trial 1
Sonic 0¡ Trial 2
3 of each cushion type tested per trial
Combustion ModifiedFoam A
Combustion ModifiedFoam B
Fire Blocking Fabric