RANKING FLAMMABILITY OF AIRCRAFT MATERIALS USING MICROSCALE COMBUSTION
CALORIMETRY
Richard E. Lyon and Richard N. Walters*
Fire Safety Branch AAR-440FAA W.J. Hughes Technical Center
Atlantic City International Airport, NJ 08405
*Galaxy Scientific Corporation, Egg Harbor Township, NJ
International Aircraft Materials Fire Test Working GroupTrump Taj Mahal Casino, Atlantic City, NJ
March 1-2, 2005
WEB: www.fire.tc.faa.gov E-MAIL: [email protected]
RANKING FLAMMABILITY USING SMALL SCALE TEST
OUTLINE OF TALK
Flammability
• Ignition Resistance (0, 90, 60,45 Bunsen burner)
• Fire Behavior (OSU, seat cushion test, radiant
panel)
Microscale Combustion Calorimetry
• Operation and Theory
• Comparison of Results for Hidden Materials
• Heat Release Rate (OSU)
• Bunsen Burner tests
• Smoke Density
• Radiant Panel
• 1/4-scale tests
FAA FLAMMABILITY TESTS
Seat CushionOil Burner Test
Radiant Panel Test
OSU HRR Test
Bunsen Burner Tests
SCALES OF FLAMMABILITY TESTING
SAMPLE SIZE
FlameTests
Fire Tests
Bench-Scale Component-Scale
MicroscaleCombustion Calorimetry
Kilogram Metric TonGramMilligram
STEADY BURNING: Nylon 6 data
500
1000
1500
2000
0 20 40 60 80 100 120
PA6
External Heat Flux, kW/m2
HRP
1421
Slopes = HRP
Intercepts = HRR0
HRR0
(kW/m2)
230148
Hea
t R
elea
se R
ate,
kW
/m2
Ignitability
Fire Response
HRR = HRP qnet
= HRR0 + HRP qext
.
.
-400 -200 0 200 400 600
V0
V1
V2
HB
UL
94
Rat
ing
HRR0, kW/m2 (in cone calorimeter)
Self-Propagating Self-Extinguishing
IGNITABILITY: UL 94 vs. HRR0
41 polymers,blends, andcomposites.
HEAT RELEASE RATE AND HEAT RELEAE CAPACITY
The Heat Release Capacity (HRC), is related to the heat release rate (HRR) in flaming combustion
0
500
1000
1500
2000
0 500 1000 1500 2000
Pea
k H
RR
, k
W/m
2
2
Heat Release Capacity, J/g-K
R = 0.93
PVC
PEIPPS
POM
PET
PVDF
PC
PMMA
ABSPA66
HIPS
PP
HDPE
50 kW/m2
FEP
HRR = () HRC
HRC
= Flaming combustionefficiency
= Density
= Pyrolysis depth
= Surface heating rate
HEAT RELEASE CAPACITY AND FLAMMABILITY
HRR0 HRR* = HRC*
HEAT RELEASE RATE
IGNITABILITY
HRR HRC*
Self extinguishing when:
For a particular heat flux (e.g., 3.5 W/cm2):
MEASURING HEAT RELEASE CAPACITY
Flaming Combustion Pyrolysis-Combustion
Flow Calorimetry (PCFC)
Exhaust
DAQO2
Pyrolysis
Combustion
Sample
GasScrubber
Gas Flow-meter
O2
Meter
N2
FLAMMABILITY TESTING OF MILLIGRAM SAMPLES
Stand Alone Device
FAA/Galaxy Invention
TGA CombustionAccessory
HEAT RELEASE CAPACITY FROM PCFC
260 W/g
= 1 K/s
€
ηc =260W/ g
1K /s
€
=260J
g−K
0
100
200
300
400
500
250 300 350 400 450 500 550
Hea
t R
elea
se R
ate
(W/g
)
Temperature (°C)
PCFC DATA & FIRE TESTS
• OSU HRR• Bunsen Burner Ignition• Radiant Panel• Oil Burner Seat Test
• Oxygen Bomb Calorimeter
• Setchkins Furnace• Glow Wire Ignition
Relevant FAAFlammability Test
Burning Rate
Heat of Combustion
IgnitionTemperature
PMMA
Combustion Calorimetry Data
IGNITION RESISTANCE (UL 94) AND HRC
10 100 1000 10,000
HB
V2
V1
V0
Heat Release Capacity, J/g-K
UL 94Rating
Halogen containing F
lam
mab
ility
IGNITION RESISTANCE (LOI) AND HRC
0
20
40
60
80
100
10 100 1000
Lim
itin
g O
xyg
en I
nd
ex (
LO
I),
%O
2
Heat Release Capacity, J/g-K
10,000
Halogen containing
12 SECOND VERTICAL BURN TEST AND HRC
0
2
4
6
8
10
-2
0
2
4
6
8
10
0 100 200 300 400 500 600
Bu
rn L
eng
th (
cm)
Bu
rn T
ime (seco
nd
s)
HRC (J/g-K)
Hidden Materials
1
10
100
10 100 1000 104
Engineering PlasticsCommodity PlasticsHidden Area Components
HE
AT
RE
LE
AS
E P
AR
AM
ET
ER
HRC (J/g-K)
FIRE (HRP) AND MATERIAL (HRC) PROPERTIES
HRP = HRC
qnet
cp
Slope should be relativelyconstant for plastics forwell-ventilated burning
0
50
100
150
200
250
300
350
0 100 200 300 400 500 600 700
OS
U P
ea
k H
RR
, kW
/m2
Heat Release Capacity, J/g-K
R = 0.72
Engineering Thermoplastics(0.060 inch sheet)
HRR (OSU PEAK) AND HRC
0.01
0.1
1
10
100
1000
0 100 200 300 400 500 600
Sm
oke
Den
sity
, D s
HRC (J/g-K)
NBS SMOKE DENSITY AND HRC
Hidden Materials
0
5
10
15
20
25
0 100 200 300 400 500 600
BU
RN
TIM
E,
seco
nd
s
HRC (J/g-K)
RADIANT PANEL TEST AND HRC
Hidden Materials
TEMPERATURE RISE AND HRC OF INSULATION BAGS
PVF1 (120 J/g-K)
PUF block, Baseline
MPET (262 J/g-K)
PI-O (47 J/g-K)
PET1 (138 J/g-K)
PET3 (250 J/g-K)
PET00 (155 J/g-K)
INTERMEDIATE SCALE TEST AND HRC
0 50 100 150 200 250
Metalized Mylar Bag
Hook & Loop (married)
Cockpit Headliner
GRP Duct
Plastic Conduit
Ceiling Panel (back)
Flexside Duct
Ceiling Panel (face)
Silicone Rubber
Foam Core Duct
SwissAir 111 Database HRC (J/g-K)
HIDDEN MATERIALS: Accident Investigation
PassOSUHRR
PassBunsenBurner
FLAMMABLE
Fla
mm
abil
ity
(J/
g-K
)
PP PE
PS
PET
ABS
PMMA
Epoxy
POM
NYLON 66
PC
PPOPU
Polyarylate
PPSF
PPS
PES
PEI LCP's
PAI
PEKPEEK
0.1 1 10 100
Price of Plastic ($/lb)
Phenolic
(KAPTON) PI
1000
10
100
PVF (TEDLAR)
Specialty Plastics
PolysulfonePVC (rigid)
FAA Research Plastics
Common Plastics
Current Aircraft
FAA Goal
FLAMMABILITY (HRC) RANKING BY COST
Resin Plastic
Flammable
CONCLUSIONS
Heat release capacity HRC is a qualitative predictor of fire performance and flammability of aircraft materials
Swelling, dripping, and barrier formation influence flame/fire tests but do not effect HRC.