Development of Fire Test for Aircraft Seat Cushions

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).



Example of Post-Crash Fire

DC10, JFK, 1976, bird strike



Example of a Post-Crash Fire

DC10, LAX, 1978, tire failure



Post-Crash Fire Simulation in Full Scale Indoor Fire Test Facility at FAA



Full Scale Cabin Mockup





Ignition Source by Fire Scenario



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



StandardNFR Seating



No Fire Blocker Fire Blocker

Effectiveness of Fire Blocking Layerat 2 minutes into test



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



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)



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



Development of a Laboratory Test for Aircraft Seat Cushions

Welded Steel Test Frame on Load Cell 2-min Exposure to Oil Burner



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



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.



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



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



Burner Alignment

Top View

Front View



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



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



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%



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.



*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



Recent Work at FAA to Standardize Oil Burner

Sonic Nozzle @ 2.0 gal/hour



NexGen Burner Design


FAA Oil Burner Test for Seat CushionsACO Seminar, April 2013

Comparison of Sonic Vs. Park BurnerSeat Burner Comparison

0.00%

1.00%

2.00%

3.00%

4.00%

5.00%

6.00%

7.00%

8.00%

9.00%

10.00%

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

Business

Development of Fire Test for Aircraft Seat Cushions