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: Richard.E.Lyon@faa.gov

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.