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Louise C. SpeitelFire Safety Branch ATO-P, AJP-6320FAA W.J. Hughes Technical Center

Atlantic City International Airport, NJ 08405

Gas Analysis and Toxicity Assessment of Combustion Products of Aircraft Materials

Materials Working Group MeetingAtlantic City, NJ. March 20-21, 2006

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OUTLINE OF TALK

• FAA Gas Analysis Instrumentation

• Requirements for Toxicity Assessment of Combustion Gases

• The FAA Toxicity Model

• FTIR Method

• FTIR Results: Response Times, Gas Histories, Toxicity

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CHEMISTRY & MATERIAL SCIENCE LABORATORY

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TGA WITH EVOLVED GAS MONITORING

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TGA-DTA WITH EVOLVED GAS MONITORING

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GAS CHROMATOGRAPH WITH MASS SPECTOMETER(GC-MS) WITH PYROPROBE

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FOURIER TRANSFORM INFRARED SPECTROMETER(FTIR) WITH PYROPROBE

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ION CHROMATOGRAPH WITH ELECTROCHEMICAL& AMPEROMETRIC DETECTORS

GASES:

HCN

HF

HCl

HBr

HI

I2H2S

SOx

NOx

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PROCESS ANALYZERS:

GASES:

CO

CO2

O2

Halo-carbons

THC

Water

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FTIR PROCESS ANALYTICAL SYSTEM

GASES:

COCO2HCNNH3NO NO2SO2HFHClHBrCOF2H2S

… etc.

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REQUIREMENTS FOR TOXICITY ASSESSMENT OF COMBUSTION GASES

• Combustion conditions of test must match fire to be

modeled

• Quick time to full response for gas measurements

• Operational simplicity: fire test, gas analysis and toxicity

calculations

• Estimate of the reliability of each gas measurement as a

function of time

• Valid toxicity model

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FAA TOXICITY MODEL: FEDI & FEDL

For a constant concentration of a toxic gas:

The effect is predicted to occur when FEDEffect =1

Incapacitation& Lethality Models

If the concentration varies with time:

t effect

t = Ct effect

Ct = effect cause to dose Ct effectivet time at received dose = FEDeffect

∫=t

oEffect

Effect tdt FED

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FAA TOXICITY MODEL

HeatIGasesII FEDFEDFED +=

HeatIOLowINOiCOIAcroleinI

HBrIHFIHClIHCNICOI

FEDFEDFEDFEDFED

FEDFEDFEDFEDFED

++++

+++++=

222

8.6)9086.12496.0(exp

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+×= CO

COC

V where = % CO22COC

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FAA TOXICITY MODEL dtCV

. = COCO∫ × )(

425031

2

when 2COV × CCO > 0.01%

dtCV

+ HCNCO∫

−×

564)63(

2 when 2COV × CHCN > 63 ppm

∫ −××++ + )]300/()1036.3[(3

2

5HClCO CV

dt

when 2COV × CHCl > 300 ppm

∫ −××++ + )]136/()1053.1[(0.3

2

5HFCO CV

dt

when 2COV × CHF > 136 ppm

∫ −××++ + )]300/()1036.3[(3

2

5HBrCO CV

dt

when 2COV × CHBr > 300 ppm

∫ +××++ + )]500/()100.4[(50.1

2

4AcroleinCO CV

dt when 2COV × CAcrolein > 300 ppm

∫ +×

−×+ 41014.1

)290(22

dtCV NOCO when 2COV ×

2NOC > 290 ppm

∫ ×−+

)5189.01623.6(exp2COC

dt when 2COC > 7.0%

∫ ×−+

26.3118.2193 COC

dt

when 5.5 ≤ 2COC ≤ 7.0%

∫ −−+

)%9.20(511.055.8(exp 2Odt

when % O2 < 11%

dtT∫+×+ 61.3

8101.41

when T > 50°C

FEDI

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REFERENCE

L. Speitel ,“Toxicity Assessment of Combustion Gases and

Development of a Survival Model”, Federal Aviation

Administration, W.J.H. Technical Center, Report No.

DOT/FAA/AR-95-5, July 1995

See http:/www.fire.tc.faa.gov

L. Speitel, “Fractional Effective Dose Model for Post-crash

Aircraft Survivability”, Toxicology, Volume 115, pp.167-

177, 1996, Copyright 1996 by Elsevier Science Ireland Ltd.

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FAA FTIR SYSTEM AND METHOD

• Extractive FTIR analytical system to analyze rapidly

changing moist fire gas concentrations as a function of time

for 20 gases

• Short system response times

• Quantitative evaluation over wide dynamic range

• Estimate of reliability of each gas measurement over time

• 20+ gas method with low residuals

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0 30 60 90 180120 150 210 270

Time (seconds)

Con

cent

ratio

n Et

hyle

ne (

ppm

)

70

60

50

40

30

20

10

0

DYNAMIC FTIR SYSTEM RESPONSE WITH GAS INTRODUCED AT HEATED SAMPLE LINE INLET

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FTIR CALIBRATION SPECTRA OF SIXTEEN GASES AT 170 DEGREES C: FULL-SCALE

H20, 3%Phosgene

SO2

COF2

NOHF

HCNHClHBrNO2

C2H2

COCH4

C2H6

C2H4

CO2

5001000150020002500300035004000Wavenumbers (cm-1)

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FTIR SPECTRA OF MIXED PLASTIC SPECIMENS

Nonflaming

0.0

0.4

0.8

1.2

Abs

orba

nce

Flaming

0.0

0.4

0.8

1.2

Abs

orba

nce

1000 20003000 4000

Wavenumbers(cm-1)

1500 25003500 4500

H2OHCl

+Unknown

gases

CO2

CO

H2O

C2H4

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FIRE GAS HISTORIES FOR DUPLICATE NONFLAMING TESTS OF MIXED PLASTIC SPECIMEN

240 300 360 420

Time (seconds)

Con

cent

ratio

n H

Cl,

CO

2(p

pm)

-10

0

10

20

30

40

50

60

70

80

90

100C

oncentration All O

ther Gases (ppm

)

CO2

HCL

CO

HCN

methane

-100

0

100

200

300

400

500

600

700

800

900

1000

0 60 120 180

ethylene

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FIRE GAS HISTORIES FOR DUPLICATE FLAMING TESTS OF MIXED PLASTIC SPECIMEN

0

2

4

6

8

10

12

14

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0 60 120 180 240 300 360 420 480 540 600Time (seconds)

Con

cent

ratio

n H

20, C

O2,

HC

l, C

O(p

arts

per

thou

sand

)

0

20

40

60

80

100

120

140

160

Concentration A

ll Other G

ases(parts per m

illion)

CO

CO2

HCl

waterAcetylene

HCN

NO

Ethylene

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TOXICITY ASSESSMENT OF MATERIALS IN FIRE

OBJECTIVES

• Develop software that calculates toxicity histories and

mass balance histories for a cone calorimeter-FTIR test.

• The FAA models for incapacitation and lethality form

the basis for the calculations. (FAA Report

DOT/FAA/AR-95-5).

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TOXICITY HISTORIES OF FLAMING MIXED PLASTIC SPECIMEN

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TOXICITY HISTORIES OF NONFLAMING MIXED PLASTIC SPECIMEN

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MASS BALANCE (KG) OF FLAMING MIXED PLASTIC SPECIMEN

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MASS BALANCE (KG) OF NONFLAMING MIXED PLASTIC SPECIMEN

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FEDI OF FLAMING MIXED PLASTIC SPECIMEN

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FEDTOTAL OF FLAMING AND NONFLAMING MIXED PLASTIC SPECIMEN

NONFLAMING

FLAMING