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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