NIST Technical Note 1761 

Smoke Component Yields from Benchscale Fire Tests: 2. ISO 19700 

Controlled Equivalence Ratio Tube 

Furnace 

Nathan D. Marsh 

Richard G. Gann 

Marc R. Nyden 

http://dx.doi.org/10.6028/NIST.TN.1761 

 

NIST Technical Note 1761 

Smoke Component Yields from Benchscale Fire Tests: 2. ISO 19700 

Controlled Equivalence Ratio Tube 

Furnace 

Nathan D. Marsh 

Richard G. Gann 

Marc R. Nyden 

Fire Research Division 

Engineering Laboratory 

http://dx.doi.org/10.6028/NIST.TN. 1761 

December 2013 

U.S. Department of Commerce 

Penny Pritzker, Secretary 

National Institute of Standards and Technology 

Patrick D. Gallagher, Under Secretary of Commerce for Standards and Technology and Director 
Certain commercial entities, equipment, or materials may be identified in this 

 document in order to describe an experimental procedure or concept adequately. 

Such identification is not intended to imply recommendation or endorsement by the 

National Institute of Standards and Technology, nor is it intended to imply that the 

entities, materials, or equipment are necessarily the best available for the purpose. 

National Institute of Standards and Technology Technical Note 1761
 

Natl. Inst. Stand. Technol. Tech. Note 1761, 45 pages (December 2013) 

http://dx.doi.org/10.6028/NIST.TN. 1761 

CODEN: NTNOEF
 
ABSTRACT 

A standard procedure is needed for obtaining smoke toxic potency data for use in fire hazard and 

risk analyses. Room fire testing of finished products is impractical, directing attention to the use 

of apparatus that can obtain the needed data quickly and at affordable cost. This report presents 

examination of the second of a series bench-scale fire tests to produce data on the yields of toxic 

products in both pre-flashover and post-flashover flaming fires. The apparatus is the ISO/TS 

19700 controlled equivalence ratio tube furnace. This apparatus uses a mechanical feed 

mechanism to supply solid fuel into a tube furnace at a pre-determined rate, so that the global 

equivalence ratio can be adjusted. The test specimens were cut from finished products that were 

also burned in room-scale tests: a sofa made of upholstered cushions on a steel frame, 

particleboard bookcases with a laminated finish, and household electric cable. Initially, the 

standard test procedure was followed for two fire stages, well ventilated flaming and postflashover. Subsequent variation in the procedure included dicing the specimen, further 

decreasing the equivalence ratio (well ventilated flaming) or increasing it (post-flashover), 

increasing the mass loading while maintaining the equivalence ratio, and increasing the fuel feed 

rate while maintaining the equivalence ratio. 

The yields of CO2 CO, HCl, and HCN were determined. The yields of other toxicants (NO, 

NO2, formaldehyde, and acrolein) were below the detection limits, but volume fractions at the 

detection limits were shown to be of limited toxicological importance relative to the detected 

toxicants. In general, the largest effects were seen between the two fire stages. The other 

variations within the fire stage had minor effects on gas yields. Under post-flashover conditions, 

the sum of the CO2 and CO yields frequently accounted for half or less of the carbon originally 

in the specimen. As a result, the gaseous combustion products cannot be used to estimate the 

mass burning rate. Under post flashover conditions, the CO yield for the sofa approached the 

value of 0.2 found in real-scale postflashover fire tests. However, for the bookcase and cable it 

did not. Yields of HCl from the cables generally approached their notional yields under wellventilated conditions, and HCN was most readily detected from the sofa under post-flashover 

conditions at toxicologically significant concentrations. 

Keywords: fire, fire research, smoke, room fire tests, fire toxicity, smoke toxicity 

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TABLE OF CONTENTS
 

LIST OF FIGURES ....................................................................................................................................................... VI
 

LIST OF TABLES......................................................................................................................................................... VI
 

I. INTRODUCTION......................................................................................................................................... 1
 

A. CONTEXT OF THE RESEARCH ................................................................................................................................1
 

B. OBTAINING INPUT DATA ......................................................................................................................................2
 

C. PRIOR ROOM‐SCALE TESTS...................................................................................................................................3
 

1. Test Configuration........................................................................................................................................3
 

2. Combustibles................................................................................................................................................3
 

D. PHYSICAL FIRE MODELS........................................................................................................................................5
 

II. EXPERIMENTAL INFORMATION ................................................................................................................. 7
 

A. SUMMARY OF ISO 19700 APPARATUS ..............................................................................................................7
 

1. Hardware .....................................................................................................................................................7
 

2. Test Operation............................................................................................................................................10
 

3. Gas Sampling and Analysis Systems...........................................................................................................10
 

B. OPERATING PROCEDURES ..............................................................................................................................14
 

1. "Standard" Testing.....................................................................................................................................14
 

2. Test Specimens...........................................................................................................................................14
 

3. Test Procedure Variation............................................................................................................................14
 

C. DATA COLLECTION..........................................................................................................................................16
 

III. CALCULATION METHODS..........................................................................................................................17
 

A. MASS LOSS RATE .............................................................................................................................................17
 

B. NOTIONAL GAS YIELDS....................................................................................................................................17
 

C. CALCULATED GAS YIELDS ................................................................................................................................18
 

1. CO and CO2 .................................................................................................................................................18
 

2. HCl and HCN...............................................................................................................................................18
 

3. Other Gases................................................................................................................................................18
 

IV. RESULTS...................................................................................................................................................19
 

A. TESTS PERFORMED .........................................................................................................................................19
 

B. CALCULATIONS OF TOXIC GAS YIELDS WITH UNCERTAINTIES ....................................................................26
 

V. DISCUSSION.............................................................................................................................................31
 

A. OVERALL TEST VALUES....................................................................................................................................31
 

B. SPECIMEN PERFORMANCE AND TEST REPEATABILITY....................................................................................31
 

1. General observations .................................................................................................................................31
 

2. CO2 and CO....................................................................................................................................................32
 

3. HCl and HCN...............................................................................................................................................35
 

C. MEASURED VS. NOTIONAL VALUES ................................................................................................................35
 

D. SPECIES SAMPLING AND MEASUREMENT ......................................................................................................36
 

1. Species Measurement Using FTIR Spectroscopy ........................................................................................36
 

E. IMPORTANCE OF UNDETECTED GASES ...........................................................................................................36
 

VI. CONCLUSION ...........................................................................................................................................39
 

VII. ACKNOWLEDGMENTS .................................................................................................................................41
 

REFERENCES......................................................................................................................................................43
 

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LIST OF FIGURES 

FIGURE 1. SCHEMATIC OF THE ISO/TS 19700 TUBE FURNACE ...................................................................................................7
 

FIGURE 2. PHOTOGRAPH OF THE NIST ISO/TS 19700 TUBE FURNACE........................................................................................7
 

FIGURE 3. CLOSEUP OF THE SAMPLING AND DILUTION CHAMBER.................................................................................................8
 

FIGURE 4. FURNACE TEMPERATURE PROFILE AT A 650 oC SETPOINT ............................................................................................9
 

FIGURE 5. FURNACE TEMPERATURE PROFILE AT A 825 oC SETPOINT ............................................................................................9
 

FIGURE 6. FTIR SPECTRUM OF THE PRODUCTS OF BURNING ELECTRICAL CABLE............................................................................12
 

FIGURE 7. PHOTOGRAPHS OF TEST SPECIMENS IN THE SAMPLE BOAT .........................................................................................15
 

FIGURE 8. CLOSE‐UP OF THE SOFA SPECIMEN BURNING UPSTREAM OF THE FURNACE......................................................................32
 

FIGURE 9. MEASURED CO (DOTTED) AND CO2 (SOLID) VOLUME FRACTIONS IN THE DILUTION CHAMBER WHEN BURNING A PVC‐CLAD
 

ELECTRICAL CABLE. RECTANGLES INDICATE THE TIME PERIOD FROM WHICH THE AVERAGE VOLUME FRACTION IS DETERMINED......33
 

FIGURE 10. RAW DATA FROM BOOKCASE MATERIAL TEST B‐1‐825‐2‐40...................................................................................34
 

LIST OF TABLES 

TABLE 1. ELEMENTAL ANALYSIS OF FUEL COMPONENTS.............................................................................................................4
 

TABLE 2. SPECIES AND FREQUENCY WINDOWS FOR FTIR ANALYSIS............................................................................................13
 

TABLE 3. CALCULATED NOTIONAL YIELDS OF TOXIC PRODUCTS FROM THE TEST SPECIMENS. ..........................................................17
 

TABLE 4. DATA FROM BOOKCASE MATERIAL TESTS .................................................................................................................20
 

TABLE 5. DATA FROM SOFA MATERIAL TESTS ........................................................................................................................21
 

TABLE 6. DATA FROM CABLE MATERIAL TESTS .......................................................................................................................22
 

TABLE 7. GAS YIELDS FROM BOOKCASE MATERIAL TESTS .........................................................................................................23
 

TABLE 8. GAS YIELDS FROM SOFA MATERIAL TESTS.................................................................................................................24
 

TABLE 9. GAS YIELDS FROM CABLE MATERIAL TESTS ...............................................................................................................25
 

TABLE 10. YIELDS OF COMBUSTION PRODUCTS FROM TUBE FURNACE TESTS...............................................................................26
 

TABLE 11. FRACTIONS OF NOTIONAL YIELDS..........................................................................................................................28
 

TABLE 12. LIMITS OF IMPORTANCE OF UNDETECTED TOXICANTS................................................................................................37
 

TABLE 13. LIMITS OF IMPORTANCE OF UNDETECTED TOXICANTS WITH ADJUSTED ACROLEIN CONTRIBUTION......................................38
 

vi 
 

 

I. INTRODUCTION 

A. CONTEXT OF THE RESEARCH 

Estimation of the times that building occupants will have to escape, find a place of refuge, or 

survive in place in the event of a fire is a principal component in the fire hazard or risk 

assessment of a facility. An accurate assessment enables public officials and facility owners to 

provide a selected or mandated degree of fire safety with confidence. Without this confidence, 

regulators and/or designers tend to apply large safety factors to lengthen the tenable time. This 

can increase the cost in the form of additional fire protection measures and can eliminate the 

consideration of otherwise desirable facility designs and construction products. Error in the 

other direction is also risky, in that if the time estimates are incorrectly long, the consequences of 

a fire could be unexpectedly high. 

Such fire safety assessments now rely on some form of computation that takes into account 

multiple, diverse factors, including the facility design, the capabilities of the occupants, the 

potential growth rate of a design fire, the spread rates of the heat and smoke, and the impact of 

the fire effluent (toxic gases, aerosols, and heat) on people who are in or moving through the fire 

vicinity.1

 The toolkit for these assessments, while still evolving, has achieved some degree of 

maturity and quality. The kit includes such tools as: 

 Computer models of the movement and distribution of fire effluent throughout a facility. 

o	 Zone models, such as CFAST2, have been in use for over two decades. This 

model takes little computational time, a benefit achieved by simplifying the air 

space in each room into two zones. A number of laboratory programs, validation 

studies,3 and reconstructions of actual fires have given credence to the 

predictions.4 

o	 Computational fluid dynamics (CFD) models, such as the Fire Dynamics 

Simulator (FDS)5, have seen increased use over the past decade. FDS is more 

computationally intense than CFAST in order to provide three-dimensional 

temperature and species concentration profiles. There has been extensive 

verification and validation of FDS predictions.5 

These models calculate the temperatures and combustion product concentrations as the 

fire develops. These profiles can be used for estimating when a person would die or be 

incapacitated, i.e., is no longer able to effect his/her own escape. 

 Devices such as the cone calorimeter6 and larger scale apparatus7, which are routinely 

used to generate information on the rate of heat release as a commercial product burns. 

 A number of standards from ISO TC92 SC3 that provide support for the generation and 

use of fire effluent information in fire hazard and risk analyses.8 Of particular 

importance is ISO 13571, which provides consensus equations for estimating the human 

incapacitating exposures to the narcotic gases, irritant gases, heat, and smoke generated 

in fires.9 

More problematic are the sources of data for the production of the harmful products of 

combustion. Different materials can generate fire effluent with a wide range of toxic potencies. 

Most furnishing and interior finish products are composed of multiple materials assembled in a 

variety of geometries, and there is as of yet no methodology for predicting the evolved products 

1 
 

from these complex assemblies. Furthermore, the generation of carbon monoxide (CO), the most 

common toxicant, can vary by orders of magnitudes, depending on the fire conditions.10 

An analysis of the U.S. fire fatality data11 showed that post-flashover fires comprise the leading 

scenarios for life loss from smoke inhalation. Thus, it is most important to obtain data regarding 

the generation of harmful species under post-flashover (or otherwise underventilated) 

combustion conditions. Data for pre-flashover (well-ventilated) conditions have value for 

ascertaining the importance of prolonged exposure to "ordinary" fire effluent and to short 

exposures to effluent of high potency. 

B. OBTAINING INPUT DATA 

The universal metric for the generation of a toxic species from a burning specimen is the yield of 

that gas, defined as the mass of the species generated divided by the consumed mass of the 

specimen.12 If both the mass of the test specimen and the mass of the evolved species are 

measured continuously during a test, then it is possible to obtain the yields of the evolved species 

as the burning process, and any chemical change within the specimen, proceeds. If continuous 

measurements are not possible, there is still value in obtaining a yield for each species integrated 

over the burning history of the test specimen. 

The concentrations of the gases (resulting from the yields and the prevalent dilution air) are 

combined using the equations in ISO 13571 for a base set of the most prevalent toxic species. 

Additional species may be needed to account for the toxic potency of the fire-generated 

environment. 

To obtain an indicator of whether the base list of toxic species needs to be enhanced, living 

organisms should also be exposed to the fire effluent. The effluent exposure that generates an 

effect on the organisms is compared to the effect of exposure to mixtures of the principal toxic 

gases. Disagreement between the effluent exposure and the mixed gas exposure is an indicator 

of effluent components not included in the mixed gas data or the existence of synergisms or 

antagonisms among the effluent components. This procedure has been standardized, based on 

data developed using laboratory rats.13,14 However, it is recognized that animal testing is not 

always possible. In these cases, it is important to identify, from the material degradation 

chemistry, a reasonable list of the degradation and combustion products that might be harmful to 

people. 

Typically, the overall effluent from a harmful fire is determined by the large combustibles, such 

as a bed or a row of auditorium seats. The ideal fire test specimen for obtaining the yields of 

effluent components is the complete combustible item, with the test being conducted in an 

enclosure of appropriate size. Unfortunately, reliance on real-scale testing of commercial 

products is impractical, both for its expense per test and for the vast number of commercial 

products used in buildings. Such testing is practical for forensic investigations in which there is 

knowledge of the specific items that combusted. 

A more feasible approach for obtaining toxic gas yields for facility design involves the use of a 

physical fire model – a small-scale combustor that captures the essence of the combustible and of 

the burning environment of interest. The test specimen is an appropriate cutting from the full 

combustible. To have confidence in the accuracy of the effluent yields from this physical fire 

model, it must be demonstrated: 

2 
	 How to obtain, from the full combustible, a representative cutting that can be 

accommodated and burned in the physical fire model; 

	 That the combustion conditions in the combustor (with the test specimen in place) are 

related to the combustion conditions in the fire of interest, generally pre-flashover 

flaming (well ventilated or underventilated), post-flashover flaming, pyrolysis, or 

smoldering; 

	 How well, for a diverse set of combustible items, the yields from the small-scale 

combustor relate to the yields from real-scale burning of the full combustible items; and 

	 How sensitive the effluent yields are to the combustor conditions and to the manner in 

which the test specimen was obtained from the actual combustible item. 

At some point, there will be sufficient data to imbue confidence that testing of further 

combustibles in a particular physical fire model will generate yields of effluent components with 

a consistent degree of accuracy. 

The National Institute of Standards and Technology (NIST) has completed a project to establish 

a technically sound protocol for assessing the accuracy of bench-scale device(s) for use in 

generating fire effluent yield data for fire hazard and risk evaluation. In this protocol, the yields 

of harmful effluent components are determined for the real-scale burning of complete finished 

products during both pre-flashover and post-flashover conditions. Specimens cut from these 

products are then burned in various types of bench-scale combustors using their standard test 

protocols. The test protocols are then varied within the range of the combustion conditions 

related to these fire stages to determine the sensitivity of the test results to the test conditions and 

to provide a basis for improving the degree of agreement with the yields from the room-scale 

tests. 

This report continues with a brief description of the previously conducted room fire tests. The 

full details can be found in Reference 15. Following this recap are the details of the tests using 

the second of four bench-scale apparatus to be examined. 

C. PRIOR ROOM-SCALE TESTS 

1. Test Configuration 

With additional support from the Fire Protection Research Foundation, NIST staff conducted a 

series of room-fire tests of three complex products.15 The burn room was 2.44 m wide, 2.44 m 

high, and 3.66 m long (8 ft x 8 ft x 12 ft). The attached corridor was a 9.75 m (32 ft) long 

extension of the burn room. A doorway 0.76 m (30 in.) wide and 2.0 m (80 in.) high was 

centered in the common wall. The downstream end of the corridor was fully open. 

2. Combustibles 

Four fuels were selected for diversity of physical form, combustion behavior, and the nature and 

yields of toxicants produced. Supplies of each of the test fuels were stored for future use in 

bench-scale test method assessment. 

	 “Sofas” made of up to 14 upholstered cushions supported by a steel frame. The cushions 

consisted of a zippered cotton-polyester fabric over a block of a flexible polyurethane 

(FPU) foam. The fire retardant in the cushion padding contains chlorine atoms. Thus, 

3 
this fuel would be a source of CO2, CO, HCN, HCl, and partially combusted organics. 

The ignition source was the California TB133 propane ignition burner16 faced downward, 

centered over the center of the row of seat cushions. In all but two of the tests, the sofa 

was centered along the rear wall of the burn room facing the doorway. In the other two 

tests, the sofa was placed in the middle of the room facing away from the doorway to 

compare the burning behavior under different air flow conditions. Two of the first group 

of sofa tests were conducted in a closed room to examine the effect of vitiation on fire 

effluent generation. In these, an electric “match” was used to initiate the fires. 

	 Particleboard (ground wood with a urea formaldehyde binder) bookcases with a 

laminated polyvinylchloride (PVC) finish. This fuel would be a source of CO2, CO, 

partially combusted organics, HCN, and HCl. To sustain burning, two bookcases were 

placed in a “V” formation, with the TB133 burner facing upward under the lower shelves. 

	 Household wiring cable, consisting of two 14 gauge copper conductors insulated with 

nylon, an uninsulated ground conductor, two paper filler strips, and an outer jacket of 

plasticized PVC. This fuel would be a source of CO2, CO, HCl, and partially combusted 

organics. Two cable racks containing 3 trays each supported approximately 30 kg of 

cable in each of the bottom two trays and approximately 17 kg in each of the middle and 

top trays. The cable trays were placed parallel to the rear of the burn room. Twin 

propane ignition burners were centered under the bottom tray of each rack. 

The elemental chemistry of each combustible was determined by an independent testing 

laboratory. More details regarding the elemental analysis can be found in NIST TN 176017 . The 

elemental composition of the component materials in the fuels is shown in 

Table 1. 

Table 1. Elemental Analysis of Fuel Components. 

Sample C H N Cl P O 

Bookcase 0.481  0.6 % 0.062  0.8 % 0.029  13 % 0.0030  4 % NA 0.426  1 % 

Sofa 0.545  1 % 0.080  1 % 0.100  1 % 0.0068  16 % 0.0015  17 % 0.267  4 % 

Cable 0.576  0.5 % 0.080  1.5 % 0.021  6 % 0.323  0.4 % NA NA 

The uncertainties are the standard deviation of three elemental analysis tests, combined with the 

uncertainty of the mass fraction of individual material components, i.e. fabric vs. foam for the 

sofa. 

4 
D. PHYSICAL FIRE MODELS 

Historically, there have been numerous bench-scale devices that were intended for measuring the 

components of the combustion effluent.18,19 The combustion conditions and test specimen 

configuration in the devices vary widely, and some devices have flexibility in setting those 

conditions. Currently, ISO TC92 SC3 (Fire Threat to People and the Environment) is proceeding 

toward standardization of one of these devices, a tube furnace (ISO/TS 1970020) and is 

considering standardization of another, the cone calorimeter (ISO 5660-121) with a controlled 

combustion environment. There are concurrent efforts in Europe and ISO to upgrade the 

chemical analytical capability for a closed box test (ISO 5659-222). Thus, before too long there 

may well be diverse (and perhaps conflicting) data on fire effluent component yields available 

for any given product. This situation does not support either assured fire safety or marketplace 

stability. 

Detailed characterizations of the ISO/TS 19700 tube furnace were first published by Blomqvist 

et al. 

23 and Stec et al. 24 At the same time a comparison was conducted between this apparatus 

and the ISO 9705 room scale tests.25 More recently, the tube furnace has been used to study the 

effect on smoke particle-size distribution26 and smoke and hydrocarbon yields27 of different fire 

retardant strategies. 

The apparatus used for this work was constructed according to the 2006 version of 

ISO/TS19700. That Technical Specification has since been updated. 

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6 
II. EXPERIMENTAL INFORMATION 

A. SUMMARY OF ISO 19700 APPARATUS 

1. Hardware 

The ISO/TS 19700 tube furnace consists of three main parts: (1) a quartz tube running through 

an electrically heated furnace; (2) a 30 L dilution and sampling chamber; and (3) a specimen boat 

and drive mechanism, which can advance the specimen into the furnace at a controlled rate. 

Aspects of this apparatus are depicted in Figure 1 through Figure 3. Air is supplied at both the 

upstream end of the quartz tube and in the dilution and sampling chamber. By controlling the 

upstream air flow rate and the specimen feed rate, the equivalence ratio in the tube furnace can 

be adjusted to model several fire stages. In this work, we focus on two stages—well ventilated 

flaming and postflashover fires, and set the temperature and equivalence ratio as specified in 

ISO/TS 19700. 

Figure 1. Schematic of the ISO/TS 19700 Tube Furnace 

Figure 2. Photograph of the NIST ISO/TS 19700 Tube Furnace 

7 
Figure 3. Closeup of the Sampling and Dilution Chamber 

The furnace temperature is controlled by a proportional–integral–derivative (PID) control 

module, which reads the temperature from a type-K thermocouple located 1 cm above the quartz 

tube in the center of the furnace. This means that the setpoint for the furnace will actually 

control the maximum heat flux imposed on the specimen—at the ends of the furnace the flux will 

be considerably lower. The Technical Specification calls for the points where the temperature 

falls 100 oC below the maximum temperature be located between 125 mm and 250 mm from the 

location of the maximum temperature. Temperature profiles of the NIST furnace are shown in 

Figure 4 and Figure 5. These profiles were recorded with gas flow rates consistent with those 

used during tests. However, it is important to note that thermocouples receive radiant energy 

from the heating elements, while heat transfer to the transparent gas is less effective; therefore 

the gas temperature in the tube furnace could be considerably lower. 

The issue is further complicated when a specimen is burning in the tube. Our furnace has an 

active control system which can compensate somewhat for the additional heat input, but this is 

not a requirement of the Technical Specification. In any event, the combustion effluent is hot, 

and the gas temperature will be higher when it is present. It may also be optically thick, in which 

case it can be heated radiatively by the heating elements. 

8 
0 

100 

200 

300 

400 

500 

600 

700 

0 200 400 600 800 1000 

Temperature (°C) 

Distance from Furnace Entrance (mm) 

Figure 4. Furnace Temperature Profile at a 650 oC Setpoint 

0 

100 

200 

300 

400 

500 

600 

700 

800 

900 

0 200 400 600 800 1000 

Temperature (°C) 

Distance from Furnace Entrance (mm) 

Figure 5. Furnace Temperature Profile at a 825 oC Setpoint 

9 
2. Test Operation 

Test specimens are placed in the sample boat, which is then placed in the (cool) upstream end of 

the quartz tube. Once the appropriate temperature and air flow rate are established, data 

collection begins and the drive mechanism is activated to advance the specimen into the furnace. 

At the same time, a portion of the exhaust from the dilution chamber is diverted to gas analysis 

instruments. Ideally, the combustion of the specimen reaches some kind of steady state, from 

which gas concentrations can be established and yields derived. In our experience, complex 

items like multi-conductor cables burn in a more fluctuating and periodic way than, for example, 

simple thermoplastics. However, it is still possible to identify ignition and extinction events, and 

to determine average yields from the period in between. 

The actual equivalence ratio, which can differ from the one intended if the fraction of 

combustible in the specimen varies, was calculated based on oxygen depletion: 

DO2 1330 O  Cm.loss 

mloss O     O 

where DO2 is the oxygen depletion in the mixing and measurement chamber, as a volume 

fraction; Cm.loss is the mass-loss concentration of the test specimen, in grams per cubic meter 

(g⋅m-3); mloss is the mass-loss rate of the test specimen, in milligrams per minute (mg⋅min-1); ΨO 

is the stoichiometric oxygen mass to fuel mass ratio; O is the oxygen supply rate, in milligrams 

per minute (mg⋅min-1), given by the following equation: 

O = P × 0.209 5 × 1 330, 

where P is the primary air flow rate, in liters per min (l⋅min-1); 1 330 is a factor to convert the 

volume of oxygen to mass of oxygen at 20 °C. 

The oxygen depletion is also used to calculate the necessary primary air flow for an equivalence 

ratio of 2.0 using the formula P = DO2 × 1.193. This assumes that all of the material consumed 

in well-ventilated conditions will be consumed in underventilated conditions as well. 

Testing at each set of conditions was performed in triplicate. We report the concentrations 

measured in the dilution chamber, averaged over a period of time between 4 min and 12 min 

from the beginning of the experiment. (Although steady state burning, as defined in the current 

version of ISO/TS 19700 was not observed for our specimens, we were able to identify this time 

interval as falling between ignition- and extinction-related phenomena, and found that selecting 

data from different parts of this interval did not significantly alter the calculated average. 

However, given the characteristic mixing time of the dilution chamber of 60 s, at least 200 s of 

data should be used for calculating an average concentration.) The three time-averaged 

concentrations are then averaged. The reported uncertainty includes the standard deviation of 

this final average, which represents the run-to-run variation in the experiment. 

3. Gas Sampling and Analysis Systems 

In the room-scale tests (Section I.C), measurements were made of 12 gases. Water and methane 

were included because of their potential interference with the quantification of the toxic gases. 

Two of the toxic gases, HBr and HF, were not found in the combustion products because there 

10 
 

 

was no fluorine or bromine in the test specimens. The remaining eight toxic gases were acrolein 

(C3H4O), Carbon monoxide (CO), carbon dioxide (CO2), formaldehyde (CH2O), hydrogen 

chloride (HCl), hydrogen cyanide (HCN), nitric oxide (NO), and nitrogen dioxide (NO2). Some 

of these turned out to be generated at levels that would not have contributed significantly to the 

incapacitation of exposed people. Thus, it was deemed unlikely that animal tests would have 

added much tenability information. As a result, the same gases were monitored in the benchscale tests, and no animals were exposed. The basis for comparison between tests of the same 

combustibles at the two scales is the yields of the chemically diverse set of toxicants. 

CO and CO2 were quantified using a nondispersive infrared (NDIR) gas analyzer; oxygen was 

quantified by a paramagnetic analyzer in the same instrument. The precisions of the analyzers, 

as provided by the manufacturer, were: 

CO: 10 μL/L 

CO2: 0.02 L/L 

O2: 0.05 L/L 

For sampling from the dilution and sampling, gas was continuously drawn from through copper 

tubing of 6.35 mm outer diameter. The flow passed through a coiled tube immersed in a water 

ice bath; an impinger bottle immersed in dry ice, with its upper half filled with glass wool; and 

finally a glass fiber disk filter before reaching the pump and then finally the analyzer. The traps 

and filter removed particulates and condensable species, including water, that would otherwise 

interfere with and possibly harm the analyzer. While sampling, the flow was maintained at 1 

L/min for the CO and CO2 detectors and 0.2 L/min for the O2 detector. The analyzer itself was 

calibrated daily with zero and span gases (a mixture of 5000 μL/L CO and 0.08 L/L of CO2 in 

nitrogen, and ambient air (0.2095 L/L oxygen on a dry basis)). The span gas is certified to be 

accurate to within 2 % of the value. 

The concentrations of CO and the additional six toxic gases were measured using a Midac 

Fourier transform infrared (FTIR) spectrometer*

 equipped with an stainless steel flow cell (2 mm 

thick ZnSe windows and a 0.1 m optical pathlength), maintained at (170 ±5) °C. Samples were 

drawn through a heated 6.35 mm (1⁄4 in.) stainless steel tube from the dilution chamber. The 

sample was pulled through the sampling line and flow cell by a small pump located downstream 

from the flow cell. There were no traps or filters in this sampling line. The pump flow was 

measured at 4 L/min maximum, but was at times lower due to fouling of the sampling lines with 

smoke deposits. The instrument could collect data at 1 Hz and could also combine several scans 

per recorded spectrum. There did not appear to be any advantage to either approach, other than 

that recording fewer spectra required less storage. 

An example of a spectrum measured by FTIR spectroscopy during one such test is displayed in 

Figure 6. The series of peaks extending from about 3050 cm-1 to 2600 cm-1 are due to HCl. In 

this case, it is possible to resolve the individual frequencies corresponding to changes in the 

population of rotational states as the H-Cl bonds vibrate. This is usually only possible for small 

gas phase molecules. There are three spectral features due to CO2 that are evident in this 

*

 Certain commercial equipment, products, or materials are identified in this document in order to describe a 

procedure or concept adequately or to trace the history of the procedures and practices used. Such identification is 

not intended to imply recommendation, endorsement, or implication that the products , materials or equipment are 

necessarily the best available for the purpose. 

11 
spectrum. The most intense, centered at 2350 cm-1, corresponds to asymmetric stretching of the 

two C=O bonds. The symmetric stretch is not observed because there is no change in dipole 

moment when both O atoms move in phase. The second feature, seen as two distinct peaks 

centered at about 3650 cm-1, is an overtone band that derives from the simultaneous excitation of 

these bond-stretching modes. The third peak at about 650 cm-1 is due to the out of plane bending 

of the molecule. There are bands due to the C≡O stretching vibrations in carbon monoxide, 

centered at about 2150 cm-1. The remaining peaks in this spectrum are due to H2O. 

4500 4000 3500 3000 2500 2000 1500 1000 500

Wavenumber (cm‐1)

H2O H2O

CO

CO2

CO2

HCl

CO2

Figure 6. FTIR Spectrum of the Products of Burning Electrical Cable 

Using these spectra, gas concentrations were quantified using the Autoquant software. This is a 

software package for performing real time and off-line quantitative analyses of target 

compounds, and is based on the Classical Least Squares (CLS) algorithm as described by 

Haaland et al.28 In this method, the measured spectra are fit to linear combinations of reference 

spectra corresponding to the target compounds. 

Calibration spectra were obtained from a quantitative spectral library assembled by Midac29 and 

from a collection of spectra provided the Federal Aviation Administration who performed benchscale fire tests on similar materials.30 In this analysis, the least squares fits were restricted to 

characteristic frequency regions or windows for each compound that were selected in such a way 

as to maximize the discrimination of the compounds of interest from other components present in 

fire gases. All reference spectra were recorded at 170 °C and ambient pressure. 

The identities of the target compounds (as well as other compounds that absorb at the same 

frequencies and must, therefore, be included in the analyses), their corresponding concentrations 

12 
(expressed in units of μL/L for a mixture of the calibration gas and N2 in a 0.1 meter cell), and 

the characteristic spectral windows used in the quantitative analyses are listed in Table 2. 

Also listed in this Table are minimum detection limits (MDLs) for each of the target compounds. 

These values, which represent the lowest concentrations that can be measured with the 

instrumentation employed in these tests, were estimated as follows. The calibration spectra were 

added to test spectra (which, when possible, were selected in such a way that only the compound 

of interest was not present) with varying coefficients until the characteristic peaks of the target 

compounds were just discernible above the baseline noise. The value of signal averaging over 

ca. 100 spectra was included. The MDL values reported in Table 2 were obtained by 

multiplying these coefficients by the known concentrations of the target compound in the 

calibration mixtures. 

Water, methane and acetylene are included in the quantitative analyses because they have 

spectral features that interfere with the target compounds. The nitrogen oxides absorb in the 

middle of the water band that extends from about 1200 cm-1 to 2050 cm-1. Consequently, the real 

limits of detection for these two compounds are an order of magnitude higher than for any of the 

other target compounds. Thus, it is not surprising that their presence was not detected in any of 

the tests. 

Table 2. Species and Frequency Windows for FTIR Analysis. 

Compound 

Reference 

Volume Fraction 

(μL/L) 

Frequency 

Window (cm-1) 

Minimum 

Detection Limit 

(μL/L) 

CH4 483 2800 to 3215 20 

C3H4O 2250 850 to 1200 20 

CH2O 11300 2725 to 3000 40 

CO2 47,850 660 to 725, 2230 to 2300 800a 

CO 2410 2050 to 2225 20 

H2O 100,000 1225 to 2050, 3400 to 4000 130a 

HCl 9870 2600 to 3100 20 

HCN 507 710 to 722, 3200 to 3310 35 

NO 512 1870 to 1950 70 

NO2 70 1550 to 1620 40 a Present in the background. 

Delay times for gas flows from the sampling locations within the test structure to the gas 

analyzers were small compared to the duration of the specimen burning. The burn durations 

were near 20 min for all specimens. Combining the gas sample pumping rate and the volumes of 

the sampling lines, the delay times were about 5 s for both the fixed-gas and FTIR instruments. 

These delay times are enough to allow for a small degree of axial diffusion. However, since our 

analysis integrates the data over time, this did not adversely affect the quantification of total gas 

evolved. 

13 
B. OPERATING PROCEDURES 

1. "Standard" Testing 

The intent was to test specimens of each of the three types under condition simulating wellventilated and post-flashover conditions. The steps in the procedure are: 

 Calibrate the fixed-gas analyzer using zero and span gases, and for the oxygen span, 

ambient air. 

 Establish furnace temperature and gas flow rates for the chosen condition. 

 Weigh the specimen 

 Begin data acquisition from the gas analyzers. 

 Open the upstream end of the quartz tube. 

 Load the sample boat containing the specimen. 

 Close the quartz tube. 

 Activate the feed mechanism. 

 Observe the ignition and burning of the specimen 

 Once the feed mechanism has withdrawn the specimen, quench any residual combustion 

with nitrogen. 

 Weigh the sample boat containing any residue. 

2. Test Specimens 

Specimens were prepared by cutting a 450 mm length of one of the three specimen types, with a 

-1 cross section selected to give a combustible mass loading of approximately 25 mg⋅mm . This 

resulted in bookcase specimens that were nominally 7 mm square in cross section, sofa foam 

specimens that were nominally 25 mm square in cross section, and cable specimens that were 

single lengths cut from the spool. Each sofa specimen was covered with a strip of the upholstery 

fabric that was 25 mm by 450 mm. All specimens were kept in a conditioning room for at least 

24 hours before an experiment. Specimens were weighed before and after each experiment so 

that the total mass loss, and therefore the average mass loss rate, could be determined. 

3. Test Procedure Variation 

One of the purposes of this program was to obtain effluent composition data in tests with variants 

on the standard operating procedure. This would enable examination of the potential for an 

improved relationship with the yield data from the room-scale tests, as well as an indication of 

the sensitivity of the gas yields to the specified operating conditions. 

	 Variation in specimen conformation: specimens were tested as intact, i.e. as cut from a 

larger item and preserving the item’s structure as much as possible, and “diced”, i.e. cut 

up into 5 mm pieces and, in the case of the cable, separating the constituent layers. 

	 Changing the air flow rate, increasing by 30 % for the well ventilated condition and 

decreasing by 30% for the postflashover condition. 

14 
	 Doubling the mass loading by adding an additional length of specimen, but maintaining 

the equivalence ratio by increasing the primary air flow rate accordingly. 

	 Since the sofa specimens were already dimensionally as large as would fit in the tube 

furnace, they were cut in half instead, with the primary air flow altered to maintain the 

equivalence ratio. 

	 Increasing the feed rate by 50 %, but maintaining the equivalence ratio by increasing the 

primary air flow accordingly. 

Figure 7. Photographs of Test Specimens in the Sample Boat 

15 
C. DATA COLLECTION 

The data from the fixed gas analyzer were recorded on a personal computer using a custom-made 

data acquisition system based on National Instruments data acquisition hardware. Values were 

recorded at 1 s intervals. The FTIR spectra were recorded using the software package provided 

by the manufacturer. Spectra were recorded every 1 s to 6 s. 

16 
III. CALCULATION METHODS 

A. MASS LOSS RATE 

The specimen mass loss during a test was determined from the initial and final mass of the 

specimen in the sample boat, which has an uncertainty of 0.1 g. The mass loss rate is calculated 

from the linear fuel load and the linear feed rate. This assumes a steady state is quickly reached. 

Mass loss rates may actually be higher at the beginning and end of the experiment, implying a 

lower mass loss rate than calculated for the main portion of the experiment. This could result in 

underestimation of gas yields. 

B. NOTIONAL GAS YIELDS 

The notional, or maximum possible, gas yields (Table 3) were calculated as follows: 

 CO2: Assume all the carbon in the test specimen is converted to CO2. Multiply the 

mass fraction of C in the test specimen ( 

 Table 1) by the ratio of the molecular mass of CO2 to the atomic mass of carbon. 

 CO: Assume all the carbon in the test specimen is converted to CO. Multiply the mass 

fraction of C by the ratio of the molecular mass of CO to the atomic mass of carbon. 

 HCN: Assume all the nitrogen in the test specimen is converted to HCN. Multiply the 

mass fraction of N by the ratio of the molecular mass of HCN to the atomic mass of 

nitrogen. 

 HCl: Assume all the chlorine in the test specimen is converted to HCl. Multiply the 

mass fraction of Cl by the ratio of the molecular mass of HCl to the atomic mass of 

chlorine. 

The notional yields from the bookcase and cable specimens were assumed to be the same as the 

yields from the intact combustibles.15 The sofa specimen had a mass ratio of fabric to foam that 

differed modestly from the intact sofas. 

Table 3. Calculated Notional Yields of Toxic Products from the Test Specimens. 

Notional Yields 

Gas Bookcase Cable Sofa 

CO2 1.72 ± 1 % 2.11 ± 1 % 1.95 ± 4 % 

CO 1.09 ± 1 % 1.33 ± 1 % 1.24 ± 4 % 

HCN 0.057 ± 13 % 0.040 ± 6 % 0.193 ± 4 % 

HCl 0.0026 ± 4 % 0.332 ± 1 % 0.0069 ± 19 % 

The uncertainty in the notional yield values is determined by the uncertainty in the prevalence of 

the central element (in the bullets just above) in the combustible. For the cuttings from the sofas, 

the uncertainty in the notional yields was increased by the small variability, (estimated at 

3 percent) in the relative masses of the fabric and padding materials in the test specimen. 

17 
C. CALCULATED GAS YIELDS 

1. CO and CO2 

Yields of CO and CO2 were calculated using gas concentrations from the NDIR instrument 

averaged over several minutes, the measured flow rates of primary and secondary air, the 

temperature in the dilution chamber, and mass loss rate. 

Y = (M/Vm) × (Fv /Cm.loss) × 10 

Where M is the molar mass of the gas (g mol-1) 

Vm is the molar volume at STP i.e. 24.055 mol L-1 

Fv is the volume fraction of the gas, in % 

Cm.loss is the mass-loss concentration in g m-3, given by: 

Cm.loss = mloss × feed rate / volume flow rate 

Where mloss is m / specimen length (mg mm-1), the feed rate is in mm min-1, and the volumetric 

flow rate is in L min-1, (corrected by the ideal gas law for increased temperature.) 

As we observed previously17, the CO2 absorption band in the FTIR is saturated at normal volume 

fractions and is therefore highly non-linear. As both the FTIR and NDIR measurements were 

taken from the same location, it was not necessary to measure the CO2 concentration by FTIR 

spectroscopy. 

2. HCl and HCN 

The only calculable HCN yields were from the sofa specimens. The only calculable HCl yields 

were from the cable specimens. The FTIR spectra from these experiments were analyzed as 

described in section II.A.2. This analysis normally includes an uncertainty of 10 % of the 

reported value. Volume fractions were converted into yields using the formula above. 

3. Other Gases 

The volume fractions of the other toxic gases were always below the detection limit. Thus, the 

upper limits of the yields of these gases were estimated using their limits of detection. 

18 
IV. RESULTS 

A. TESTS PERFORMED 

The following is the test numbering key, with format F-C-T-P-R-L-N, where 

F: Fuel [S = sofas; B = bookcases; C = cable] 

C: 1 for intact, 2 for diced 

T: Furnace temperature, 650 for well ventilated or 825 for post-flashover 

P Primary air flow rate (rounded to nearest L min-1) 

R: Sample boat feed rate in mm min-1 

L: Fuel load, 1 for normal, 2 for double, 5 for one-half 

N: Replicate test number for that set of combustible and conditions 

Run codes ending with a letter “a” or “b” indicate that the run was repeated because of an error. 

Table 4 through Table 9 present the test data and the calculated yields for the bookcase, sofa, and 

cable specimens, respectively. The equivalence ratio, Φ, is calculated from the mass loss rate, 

the stoichiometric oxygen to fuel mass ratio, and the oxygen supply rate from the primary air 

flow rate. (The stoichiometric oxygen to fuel mass ratio is calculated from the oxygen depletion, 

the mass loss rate, and the total air flow rate in the well-ventilated tests for a given specimen 

type.) 

The horizontal shaded bands highlight groups of replicate tests. 

19 
 

 

 

            

            

            

      

      

      

            

            

            

      

      

      

            

            

            

                             

      

      

      

  

  

  

      

      

      

  

  

  

      

      

      

Table 4. Data from Bookcase Material Tests 

Mass Primary NDIR FTIR 

Code Specimen 

Mass (g) 

Loss Rate 

(mg/min) 

Airflow 

(L/min) 

Φ FCO2 

(L/L) 

FCO 

(L/L) 

DO2 

(L/L) 

FCO 

(L/L) 

b‐1‐650‐10‐40‐1‐001 14.8 1320 11.6 0.43 0.0168 < 10 0.019 30

b‐1‐650‐10‐40‐1‐002 14.3 1220 11.6 0.42 0.0164 < 10 0.018 30

b‐1‐650‐10‐40‐1‐003 14.8 1260 11.6 0.44 0.0171 < 10 0.019 40

b‐2‐650‐10‐40‐1‐001 14.7 1310 11.6 0.43 0.0169 < 10 0.019 60

b‐2‐650‐10‐40‐1‐002 13.7 1150 11.6 0.41 0.0162 < 10 0.018 100

b‐2‐650‐10‐40‐1‐003 13.9 1160 11.6 0.35 0.0164 < 10 0.015 50

b‐1‐650‐13‐40‐1‐001a 14.6 1230 15.1 0.34 0.0184 < 10 0.019 70

b‐1‐650‐13‐40‐1‐002 14.2 1180 15.1 0.35 0.0181 < 10 0.020 70

b‐1‐650‐13‐40‐1‐003 14.9 1260 15.1 0.38 0.0194 < 10 0.021 40

b‐1‐650‐20‐40‐2‐001 28.1 2360 22.2 0.48 0.0359 < 10 0.039 30

b‐1‐650‐20‐40‐2‐002 29.5 2460 23.1 0.46 0.0364 < 10 0.040 50

b‐1‐650‐20‐40‐2‐003 31.4 2580 23.1 0.44 0.0347 < 10 0.038 < 20

b‐1‐650‐15‐60‐1‐001 16.1 1910 17.3 0.37 0.0152 < 10 0.024 20

b‐1‐650‐15‐60‐1‐002 14.3 1730 17.4 0.41 0.0114 < 10 0.026 30

b‐1‐650‐15‐60‐1‐003 15.8 1840 17.4 0.49 0.0149 < 10 0.032 20

b‐1‐825‐2‐40‐1‐001 15.5 1200 2.61 1.89 0.0057 1660 0.007 1420

b‐1‐825‐2‐40‐1‐002 14.8 1180 2.57 1.89 0.0030 830 0.002 790

b‐1‐825‐2‐40‐1‐003 15.8 1210 2.57 1.93 0.0032 780 0.004 920

b‐2‐825‐2‐40‐1‐001 15.1 1170 2.57 1.87 0.0032 560 0.004 690

b‐2‐825‐2‐40‐1‐002 13.5 1080 2.57 1.72 0.0030 620 0.004 < 20

b‐2‐825‐2‐40‐1‐003 15.5 1220 2.57 1.94 0.0033 880 0.004 700

b‐1‐825‐1‐40‐1‐001 15.6 1160 1.76 2.71 0.0026 1280 0.004 110

b‐1‐825‐1‐40‐1‐002 14.8 1150 1.77 2.67 0.0023 830 0.003 600

b‐1‐825‐1‐40‐1‐003 15.1 1200 1.77 2.77 0.0023 1210 0.003 1090

b‐1‐825‐4‐40‐2‐001 26.9 2130 5.00 1.75 0.0067 1540 0.008 1760

b‐1‐825‐4‐40‐2‐002 28.8 2230 5.00 1.83 0.0065 2180 0.007 1830

b‐1‐825‐4‐40‐2‐003 29.1 2260 5.00 1.85 0.0059 1750 0.007 1690

b‐1‐825‐3‐60‐1‐001 15.7 1830 3.53 2.12 0.0042 1380 0.005 1240

b‐1‐825‐3‐60‐1‐002 13.8 1630 3.39 1.97 0.0044 1240 0.006 1090

b‐1‐825‐3‐60‐1‐003 14.3 1630 3.38 1.97 0.0044 1060 0.005 1240

20 
 

 

   

   

   

   

   

   

                             

                 

   

   

   

   

   

           

Table 5. Data from Sofa Material Tests 

Mass Primary NDIR FTIR 

Code Specimen 

Mass (g) 

Loss Rate 

(mg/min) 

Air flow 

(L/min) 

Φ FCO2 

(L/L) 

FCO 

(L/L) 

DO2 

(L/L) 

FCO 

(L/L) 

FHCN 

(L/L) 

s‐1‐650‐10‐40‐1‐001 10.3 870 11.6 0.44 0.0152 300 0.019 510 < 35

s‐1‐650‐10‐40‐1‐002 10.5 920 11.6 0.36 0.0141 350 0.016 490 < 35

s‐1‐650‐10‐40‐1‐003 10.2 840 11.6 0.46 0.0154 340 0.020 490 < 35

s‐1‐650‐13‐40‐1‐001 10.5 890 15.0 0.18 0.0074 190 0.010 530 < 35

s‐1‐650‐13‐40‐1‐002 10.8 940 15.1 0.18 0.0075 290 0.010 570 40

s‐1‐560‐13‐40‐1‐003 10.7 940 15.1 0.20 0.0082 440 0.011 710 60

s‐1‐650‐5‐40‐5‐001 7.8 680 6.0 0.21 0.0043 120 0.005 340 < 35

s‐1‐650‐5‐40‐5‐002 7.5 640 5.8 0.28 0.0044 100 0.006 460 < 35

s‐1‐650‐5‐40‐5‐003 7.8 680 5.8 0.26 0.0040 80 0.006 340 < 35

s‐1‐650‐15‐60‐1‐001 10.4 1290 17.3 0.22 0.0106 110 0.014 420 < 35

s‐1‐650‐15‐60‐1‐002 10.4 1320 17.4 0.19 0.0093 50 0.013 590 < 35

s‐1‐650‐15‐60‐1‐003 10.7 1350 17.4 0.17 0.0084 < 10 0.011 420 < 35

s‐1‐825‐2‐40‐1‐001 10.5 870 2.92 1.25 0.0043 1810 0.007 1680 90

s‐1‐825‐2‐40‐1‐002 13.7 920 2.92

s‐1‐825‐2‐40‐1‐003 9.7 760 2.92 1.08 0.0042 1600 0.007 1460 80

s‐1‐825‐1‐40‐1‐001 10.4 910 2.01 1.89 0.0027 2320 0.005 2250 130

s‐1‐825‐1‐40‐1‐002 10.4 900 2.00 1.88 0.0030 2150 0.005 1880 120

s‐1‐825‐1‐40‐1‐003 10.2 850 2.18 1.64 0.0030 2050 0.005 1630 100

s‐1‐825‐1‐40‐5‐001a 7.4 600 1.18 2.14 0.0009 670 0.002 290 < 35

s‐1‐825‐1‐40‐5‐002a 7.0 520 1.18 1.83 0.0010 600 0.002 840 50

s‐1‐825‐1‐40‐5‐003a 6.1 510 1.65 1.29 0.0010 470 0.000 700 40

s‐1‐825‐2‐60‐1‐001 13.5 1200 1.88 2.67 0.0030 2610 0.005 2350 180

s‐1‐825‐2‐60‐1‐002b 11.0 1280 1.89 2.84 0.0036 2700 0.006 2260 190

s‐1‐825‐2‐60‐1‐003 10.4 1240 1.88 2.76 0.0035 2910 0.007

21 
 

 

   

   

   

   

   

   

   

   

   

                             

   

   

   

   

   

   

     

Table 6. Data from Cable Material Tests 

Mass Primary NDIR FTIR 

Code Specimen 

Mass (g) 

Loss Rate 

(mg/min) 

Air flow 

(L/min) 

Φ FCO2 

(L/L) 

FCO 

(L/L) 

DO2 

(L/L) 

FCO 

(L/L) 

FHCl 

(L/L) 

c‐1‐650‐10‐40‐1‐001 39.2 950 11.6 0.36 0.0108 990 0.016 1120 2760

c‐1‐650‐10‐40‐1‐002 39.3 640 11.6 0.36 0.0108 900 0.016 1020 2720

c‐1‐650‐10‐40‐1‐003 39.1 960 11.6 0.34 0.0099 1310 0.015 1200 2660

c‐2‐650‐10‐40‐1‐001 39.2 960 11.5 0.40 0.0120 1160 0.017 1190 3320

c‐2‐650‐10‐40‐1‐002 39.6 890 11.6 0.38 0.0112 1280 0.017 1260 3050

c‐2‐650‐10‐40‐1‐003a 39.4 970 11.6 0.37 0.0110 1260 0.016 1070 2890

c‐1‐650‐13‐40‐1‐001 39.1 950 15.1 0.26 0.0099 880 0.015 910 2520

c‐1‐650‐13‐40‐1‐002 38.7 920 14.3 0.29 0.0103 1030 0.015 950 2480

c‐1‐650‐13‐40‐1‐003 39.2 940 15.1 0.26 0.0098 920 0.015 930 2690

c‐1‐650‐20‐40‐2‐001 77.7 1810 22.8 0.32 0.0197 1900 0.027 1310 3610

c‐1‐650‐20‐40‐2‐002 79.0 1940 23.1 0.32 0.0205 1740 0.028 1270 3850

c‐1‐650‐20‐40‐2‐003 77.3 1920 23.1 0.30 0.0188 2050 0.026 1960 4470

c‐1‐650‐15‐60‐1‐001 38.6 1330 17.4 0.32 0.0144 1270 0.021 1190 3580

c‐1‐650‐15‐60‐1‐002 38.8 1350 17.4 0.33 0.0151 1280 0.022 1120 3710

c‐1‐650‐15‐60‐1‐003 38.6 1350 17.4 0.32 0.0147 1240 0.021 1110 3500

c‐1‐650‐10‐20‐2‐001 76.4 930 10.0 0.50 0.0145 1420 0.021 1590 3380

c‐1‐650‐10‐20‐2‐002 75.4 920 10.0 0.47 0.0134 1340 0.020 1580 3380

c‐1‐650‐10‐20‐2‐003 76.5 930 10.0 0.48 0.0139 1350 0.020 1620 3480

c‐1‐825‐2‐40‐1‐001 39.6 950 2.23 1.71 0.0026 500 0.004 670 1680

c‐1‐825‐2‐40‐1‐002 39.8 940 2.23 1.70 0.0032 670 0.005 570 1510

c‐1‐825‐2‐40‐1‐003 40.0 950 2.23 1.71 0.0030 610 0.005 460 1140

c‐1‐825‐2‐40‐1‐001 39.1 940 2.26 1.68 0.0029 570 0.003 700 1380

c‐1‐825‐2‐40‐1‐002 38.6 940 2.23 1.69 0.0024 480 0.004 760 1530

c‐1‐825‐2‐40‐1‐003 39.5 950 2.23 1.71 0.0029 500 0.005 710 1670

c‐1‐825‐1‐40‐1‐001 40.7 940 1.55 2.45 0.0020 1650 0.004 1290 1620

c‐1‐825‐1‐40‐1‐002 40.2 930 1.53 2.44 0.0019 1360 0.004 1170 1490

c‐1‐825‐1‐40‐1‐003 40.4 950 1.54 2.49 0.0020 1110 0.004 1020 1550

c‐1‐825‐4‐40‐2‐001 80.4 1730 4.36 1.59 0.0070 1440 0.011 1160 2500

c‐1‐825‐4‐40‐2‐002 81.6 1930 4.56 1.70 0.0067 1290 0.010 1200 3150

c‐1‐825‐4‐40‐2‐003 79.8 1870 4.42 1.70 0.0071 1410 0.011 1130 3010

c‐1‐825‐2‐60‐1‐001 38.9 1370 2.74 2.01 0.0059 1680 0.010 1220 3360

c‐1‐825‐2‐60‐2‐002 38.4 1350 2.69 2.01 0.0060 1710 0.010 1200 3400

c‐1‐825‐2‐60‐1‐003 38.9 1360 2.69 2.03 0.0059 1720 0.010

22 
Table 7. Gas Yields from Bookcase Material Tests 

Primary 

Code Specimen 

Mass (g) 

Air flow 

(L/min) 

Φ yCO2 

(g/g) 

yCO 

(g/g) 

yHCN 

(g/g) 

yHCl 

(g/g) 

yNO 

(g/g) 

yNO2 

(g/g) 

b‐1‐650‐10‐40‐1‐001 14.8 11.6 0.43 1.38 < 0.0010 < 0.0018 < 0.0014 < 0.0039 < 0.0034 < 

b‐1‐650‐10‐40‐1‐002 14.3 11.6 0.42 1.45 < 0.0011 < 0.0019 < 0.0015 < 0.0042 < 0.0037 < 

b‐1‐650‐10‐40‐1‐003 14.8 11.6 0.44 1.46 < 0.0011 < 0.0018 < 0.0014 < 0.0041 < 0.0036 < 

b‐2‐650‐10‐40‐1‐001 14.7 11.6 0.43 1.40 < 0.0011 < 0.0018 < 0.0014 < 0.0039 < 0.0035 < 

b‐2‐650‐10‐40‐1‐002 13.7 11.6 0.41 1.53 < 0.0012 < 0.0020 < 0.0016 < 0.0045 < 0.0039 < 

b‐2‐650‐10‐40‐1‐003 13.9 11.6 0.35 1.53 < 0.0012 < 0.0020 < 0.0016 < 0.0045 < 0.0039 < 

b‐1‐650‐13‐40‐1‐001a 14.6 15.1 0.34 1.64 < 0.0011 < 0.0019 < 0.0015 < 0.0043 < 0.0037 < 

b‐1‐650‐13‐40‐1‐002 14.2 15.1 0.35 1.68 < 0.0012 < 0.0020 < 0.0015 < 0.0044 < 0.0039 < 

b‐1‐650‐13‐40‐1‐003 14.9 15.1 0.38 1.65 < 0.0011 < 0.0018 < 0.0014 < 0.0041 < 0.0036 < 

b‐1‐650‐20‐40‐2‐001 28.1 22.2 0.48 1.69 < 0.0006 < 0.0010 < 0.0008 < 0.0022 < 0.0020 < 

b‐1‐650‐20‐40‐2‐002 29.5 23.1 0.46 1.60 < 0.0006 < 0.0009 < 0.0007 < 0.0021 < 0.0018 < 

b‐1‐650‐20‐40‐2‐003 31.4 23.1 0.44 1.46 < 0.0005 < 0.0009 < 0.0007 < 0.0020 < 0.0018 < 

b‐1‐650‐15‐60‐1‐001 16.1 17.3 0.37 0.88 < 0.0007 < 0.0012 < 0.0010 < 0.0028 < 0.0024 < 

b‐1‐650‐15‐60‐1‐002 14.3 17.4 0.41 0.73 < 0.0008 < 0.0014 < 0.0011 < 0.0030 < 0.0027 < 

b‐1‐650‐15‐60‐1‐003 15.8 17.4 0.49 0.90 < 0.0008 < 0.0013 < 0.0010 < 0.0029 < 0.0025 < 

b‐1‐825‐2‐40‐1‐001 15.5 2.61 1.89 0.51 0.095 < 0.0019 < 0.0015 < 0.0042 < 0.0037 < 

b‐1‐825‐2‐40‐1‐002 14.8 2.57 1.89 0.28 0.048 < 0.0019 < 0.0015 < 0.0043 < 0.0038 < 

b‐1‐825‐2‐40‐1‐003 15.8 2.57 1.93 0.28 0.044 < 0.0019 < 0.0015 < 0.0042 < 0.0037 < 

b‐2‐825‐2‐40‐1‐001 15.1 2.57 1.87 0.29 0.032 < 0.0020 < 0.0015 < 0.0043 < 0.0038 < 

b‐2‐825‐2‐40‐1‐002 13.5 2.57 1.72 0.30 0.039 < 0.0021 < 0.0016 < 0.0047 < 0.0041 < 

b‐2‐825‐2‐40‐1‐003 15.5 2.57 1.94 0.29 0.049 < 0.0019 < 0.0015 < 0.0042 < 0.0037 < 

b‐1‐825‐1‐40‐1‐001 15.6 1.76 2.71 0.24 0.074 < 0.0020 < 0.0015 < 0.0043 < 0.0038 < 

b‐1‐825‐1‐40‐1‐002 14.8 1.77 2.67 0.21 0.049 < 0.0020 < 0.0015 < 0.0044 < 0.0039 < 

b‐1‐825‐1‐40‐1‐003 15.1 1.77 2.77 0.20 0.067 < 0.0019 < 0.0015 < 0.0042 < 0.0037 < 

b‐1‐825‐4‐40‐2‐001 26.9 5.00 1.75 0.34 0.050 < 0.0011 < 0.0008 < 0.0024 < 0.0021 < 

b‐1‐825‐4‐40‐2‐002 28.8 5.00 1.83 0.32 0.067 < 0.0010 < 0.0008 < 0.0023 < 0.0020 < 

b‐1‐825‐4‐40‐2‐003 29.1 5.00 1.85 0.28 0.053 < 0.0010 < 0.0008 < 0.0022 < 0.0020 < 

b‐1‐825‐3‐60‐1‐001 15.7 3.53 2.12 0.25 0.052 < 0.0013 < 0.0010 < 0.0028 < 0.0025 < 

b‐1‐825‐3‐60‐1‐002 13.8 3.39 1.97 0.29 0.052 < 0.0014 < 0.0011 < 0.0032 < 0.0028 < 

b‐1‐825‐3‐60‐1‐003 14.3 3.38 1.97 0.29 0.044 < 0.0014 < 0.0011 < 0.0032 < 0.0028 < 
Table 8. Gas Yields from Sofa Material Tests 

Primary 

Code Specimen 

Mass (g) 

Airflow (L/min) 

Φ yCO2 

(g/g) 

yCO 

(g/g) 

yHCN 

(g/g) 

yHCl 

(g/g) 

yNO 

(g/g) 

yNO2 

(g/g) 

y

s‐1‐650‐10‐40‐1‐001s‐1‐650‐10‐40‐1‐002s‐1‐650‐10‐40‐1‐003s‐1‐650‐13‐40‐1‐001s‐1‐650‐13‐40‐1‐002s‐1‐560‐13‐40‐1‐003s‐1‐650‐5‐40‐5‐001

s‐1‐650‐5‐40‐5‐003

s‐1‐650‐15‐60‐1‐001s‐1‐650‐15‐60‐1‐002s‐1‐650‐15‐60‐1‐003s‐1‐825‐2‐40‐1‐001

s‐1‐825‐2‐40‐1‐002

s‐1‐825‐2‐40‐1‐003

s‐1‐825‐1‐40‐1‐001

s‐1‐825‐1‐40‐1‐002

s‐1‐825‐1‐40‐1‐003

s‐1‐825‐1‐40‐5‐001a

s‐1‐825‐1‐40‐5‐002a

s‐1‐825‐1‐40‐5‐003a

s‐1‐825‐2‐60‐1‐001

s‐1‐825‐2‐60‐1‐002b

s‐1‐825‐2‐60‐1‐003

10.310.510.210.510.810.7

7.87.8

10.410.410.710.513.7

9.7

10.410.410.2

7.47.06.1

13.511.010.4

11.611.611.615.015.115.1

6.05.8

17.317.417.42.922.922.922.012.002.181.181.181.651.881.891.88

0.440.360.460.180.180.200.210.260.220.190.171.251.081.891.881.642.141.831.292.672.842.76

1.911.692.020.920.870.950.680.640.900.780.680.540.590.310.350.380.160.200.210.260.300.30

0.0240.0260.0280.0150.0220.0330.0120.0080.0060.002

< 0.0010

0.1420.1440.1730.1610.1650.0750.0780.0630.1470.1420.159

< 0.0027< 0.0026< 0.0028< 0.0027

0.00290.0039

< 0.0034< 0.0035< 0.0018< 0.0018< 0.0018

0.00670.01030.00740.00950.00880.0080

< 0.0037

0.00610.00540.00990.0096

< 0.0021< 0.0020< 0.0022< 0.0020< 0.0019< 0.0019

< 0.0026< 0.0027< 0.0014< 0.0014< 0.0014< 0.0020< 0.0019< 0.0024< 0.0019< 0.0020< 0.0021< 0.0029< 0.0034< 0.0034< 0.0015< 0.0014

< 0.0060< 0.0057< 0.0062< 0.0059< 0.0056< 0.0056

< 0.0076< 0.0077< 0.0041< 0.0040< 0.0039< 0.0059< 0.0056< 0.0068< 0.0056< 0.0056

< 0.006

< 0.0083< 0.0097< 0.0099< 0.0042

< 0.004

< 0.0053< 0.0050< 0.0055< 0.0052< 0.0049< 0.0049

< 0.0067< 0.0067< 0.0036< 0.0035< 0.0034< 0.0052< 0.0049< 0.0060

< 0.0049< 0.0049< 0.0053< 0.0073< 0.0085< 0.0087

< 0.0037< 0.0035

< < < < < < 

< < < < < < < < 

< < < < < < 

< < 

No FTIR data
Table 9. Gas Yields from Cable Material Tests 

Primary 

Code Specimen 

Mass (g) 

Airflow (L/min) 

Φ yCO2 

(g/g) 

yCO 

(g/g) 

yHCN 

(g/g) 

yHCl 

(g/g) 

yNO 

(g/g) 

yNO2 

(g/g) 

y

c‐1‐650‐10‐40‐1‐001c‐1‐650‐10‐40‐1‐002c‐1‐650‐10‐40‐1‐003c‐2‐650‐10‐40‐1‐001c‐2‐650‐10‐40‐1‐002c‐2‐650‐10‐40‐1‐003ac‐1‐650‐13‐40‐1‐001c‐1‐650‐13‐40‐1‐002c‐1‐650‐13‐40‐1‐003c‐1‐650‐20‐40‐2‐001c‐1‐650‐20‐40‐2‐002c‐1‐650‐20‐40‐2‐003c‐1‐650‐15‐60‐1‐001c‐1‐650‐15‐60‐1‐002c‐1‐650‐15‐60‐1‐003c‐1‐650‐10‐20‐2‐001c‐1‐650‐10‐20‐2‐002c‐1‐650‐10‐20‐2‐003c‐1‐825‐2‐40‐1‐001

c‐1‐825‐2‐40‐1‐002

c‐1‐825‐2‐40‐1‐003

c‐1‐825‐2‐40‐1‐001

c‐1‐825‐2‐40‐1‐002

c‐1‐825‐2‐40‐1‐003

c‐1‐825‐1‐40‐1‐001

c‐1‐825‐1‐40‐1‐002

c‐1‐825‐1‐40‐1‐003

c‐1‐825‐4‐40‐2‐001

c‐1‐825‐4‐40‐2‐002

c‐1‐825‐4‐40‐2‐003

c‐1‐825‐2‐60‐1‐001

c‐1‐825‐2‐60‐2‐002

c‐1‐825‐2‐60‐1‐003

39.239.339.139.239.639.439.138.739.277.7

79

77.338.638.838.676.475.476.539.639.8

40

39.138.639.540.740.240.480.481.679.838.938.438.9

11.611.611.611.511.611.615.114.315.122.823.123.117.417.417.410.010.010.02.232.232.232.262.232.231.551.531.544.364.564.422.742.692.69

0.360.360.340.400.380.370.260.290.260.320.320.300.320.330.320.500.470.481.711.701.711.681.691.712.452.442.491.591.701.702.012.012.03

1.231.841.131.361.371.241.141.241.141.211.171.081.181.231.191.521.431.460.290.370.340.330.270.320.220.220.220.440.380.410.480.500.48

0.0710.0980.0950.0830.0990.0900.0650.0780.0680.0740.0630.0750.0660.0660.0640.0940.0910.0900.0360.0490.0440.0410.0340.0360.1180.0980.0780.0580.0460.0520.0880.0900.091

< 0.0024< 0.0037< 0.0024< 0.0024< 0.0026< 0.0024< 0.0025< 0.0026< 0.0025< 0.0013< 0.0012< 0.0012< 0.0018< 0.0017< 0.0017< 0.0023< 0.0023< 0.0023< 0.0024< 0.0025< 0.0024< 0.0024< 0.0024< 0.0024< 0.0024< 0.0024< 0.0024< 0.0014< 0.0012< 0.0012< 0.0018< 0.0018

0.260.380.250.310.310.270.240.250.260.180.180.210.240.250.230.290.300.300.160.140.110.130.140.150.150.140.140.130.150.140.230.23

< 0.0054< 0.0081< 0.0054< 0.0054< 0.0058< 0.0054< 0.0055< 0.0057< 0.0055< 0.0029< 0.0027< 0.0027< 0.0039< 0.0039< 0.0039< 0.0050< 0.0051< 0.0050< 0.0054< 0.0055< 0.0054< 0.0054< 0.0054< 0.0053< 0.0053< 0.0054< 0.0053< 0.0030< 0.0027< 0.0027< 0.0039< 0.0040

< 0.0048< 0.0071< 0.0048< 0.0047< 0.0051< 0.0047< 0.0048

< 0.005

< 0.0049< 0.0026< 0.0024< 0.0024< 0.0034< 0.0034< 0.0034< 0.0044< 0.0045< 0.0044< 0.0047< 0.0048< 0.0047

< 0.0048< 0.0047< 0.0047< 0.0047< 0.0047< 0.0046

< 0.0026< 0.0023< 0.0024< 0.0034< 0.0035

< 0< 0< 0< 0< 0< 0

< 0< 0< 0< 0< 0< 0

< 0< 0< 0< 0< 0< 0< 0< 0< 0

< 0< 0< 0< 0< 0< 0

< 0< 0< 0< 0< 0

No FTIR data
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

      

 

 

 

 

 

 

 

 

B. CALCULATIONS OF TOXIC GAS YIELDS WITH UNCERTAINTIES 

Table 10 contains the yields of the combustion products calculated using the data from Table 7 

Table 8, and Table 9. The estimated uncertainties reflect the repeatability of the volume 

fractions in replicate tests, uncertainties in the other terms in the yields calculations, and degree 

of proximity of the measured values to the background levels. The Fire Stage column refers to 

pre-flashover and post-flashover, which is a better description of the conditions in the full scale 

experiments. For this work we are considering the well-ventilated mode of the tube furnace to 

be equivalent to pre-flashover. 

Table 10. Yields of Combustion Products from Tube Furnace Tests. 

Gas 

CO2 

Fire 

Stage 

Pre 

Solid

Diced 

Air x1.3 

Mass x2 

Feed x1.5 

Bookcase

 1.43 ± 3.2 % 

1.49 ± 5.0 % 

1.66 ± 1.2 % 

1.58 ± 7.2 % 

0.83 ± 11 % 

1.87 

0.91

0.66 

0.79

 Sofa 

± 

X 

± 

± 

± 

8.9 % 

4.6 % 

4.5 % 

14 % 

Cable 

1.40 ± 27 % 

1.33 ± 5.5 % 

1.17 ± 4.8 % 

1.15 ± 5.5 % 

1.20 ± 2.1 % 

Post 

Solid 

Diced 

Air x0.7 

Mass x2 

Feed x1.5 

0.36 ± 38 % 

0.29 ± 1.9 % 

0.21 ± 8.8 % 

0.31 ± 10 % 

0.28 ± 8.2 % 

0.56

0.35

0.23 

0.28

 ± 

X 

± 

± 

± 

6.6 % 

9.6 % 

18 % 

7.1 % 

0.33 ± 12 % 

0.31 ± 11 % 

0.22 ± 0.1 % 

0.41 ± 8.2 % 

0.49 ± 1.7 % 

CO 

Pre 

Solid 

Diced 

Air x1.3 

Mass x2 

Feed x1.5 

< 0.0011 

< 0.0012 

< 0.0011 

< 0.0006 

< 0.0008 

0.026 

0.023 

0.010 

0.003 

± 

X 

± 

± 

± 

10.1 % 

38.1 % 

31.0 % 

88.2 % 

0.088 ± 16 % 

0.091 ± 8.8 % 

0.070 ± 10 % 

0.071 ± 9.3 % 

0.065 ± 1.6 % 

Post 

Solid 

Diced 

Air x0.7 

Mass x2 

Feed x1.5 

0.062 ± 45 % 

0.040 ± 21 % 

0.063 ± 21 % 

0.057 ± 16 % 

0.050 ± 8.9 % 

0.143 

0.166 

0.052 

0.143 

± 

X 

± 

± 

± 

1.4 % 

3.6 % 

65.1 % 

10.4 % 

0.043 ± 14 % 

0.037 ± 9.5 % 

0.098 ± 20 % 

0.052 ± 11 % 

0.090 ± 1.7 % 

HCN 

Pre 

Solid 

Diced 

Air x1.3 

Mass x2 

Feed x1.5 

< 0.0018 

< 0.0019 

< 0.0019 

< 0.0009 

< 0.0013 

0.0032 

< 

X 

± 

< 

< 

0.0027 

30 % 

0.0035 

0.0018 

< 0.0028 

< 0.0025 

< 0.0025 

< 0.0012 

< 0.0017 

Post 

Solid 

Diced 

Air x0.7 

Mass x2 

Feed x1.5 

< 0.0019 

< 0.0020 

< 0.0020 

< 0.0010 

< 0.0014 

0.0081 

0.0088 

0.0058 

0.0098 

± 

X 

± 

± 

± 

33 % 

19 % 

19 % 

12 % 

< 0.0024 

< 0.0024 

< 0.0024 

< 0.0013 

< 0.0018 

26 
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

    

    

    

    

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 Gas 

Fire 

Stage Bookcase Sofa Cable 

HCl 

Pre 

Solid 

Diced 

Air x1.3 

Mass x2 

Feed x1.5 

< 0.0014 

< 0.0015 

< 0.0015 

< 0.0007 

< 0.0010 

< 

X 

< 

< 

< 

0.0021 

0.0019 

0.0027 

0.0014 

0.30 ± 34 % 

0.30 ± 18 % 

0.25 ± 14 % 

0.19 ± 19 % 

0.24 ± 14 % 

Post 

Solid 

Diced 

Air x0.7 

Mass x2 

Feed x1.5 

< 0.0015 

< 0.0015 

< 0.0015 

< 0.0008 

< 0.0011 

< 

X 

< 

< 

< 

0.0021 

0.0020 

0.0033 

0.0015 

0.14 ± 29 % 

0.14 ± 19 % 

0.14 ± 14 % 

0.14 ± 16 % 

0.23 ± 12 % 

NO 

Pre 

Solid 

Diced 

Air x1.3 

Mass x2 

Feed x1.5 

< 0.0041 

< 0.0043 

< 0.0043 

< 0.0021 

< 0.0029 

< 

X 

< 

< 

< 

0.0060 

0.0057 

0.0077 

0.0040 

< 0.0063 

< 0.0055 

< 0.0056 

< 0.0028 

< 0.0039 

Post 

Solid 

Diced 

Air x0.7 

Mass x2 

Feed x1.5 

< 0.0042 

< 0.0044 

< 0.0043 

< 0.0023 

< 0.0031 

< 

X 

< 

< 

< 

0.0061 

0.0057 

0.0096 

0.0041 

< 0.0054 

< 0.0054 

< 0.0053 

< 0.0028 

< 0.0040 

NO2 

Pre 

Solid 

Diced 

Air x1.3 

Mass x2 

Feed x1.5 

< 0.0036 

< 0.0038 

< 0.0037 

< 0.0019 

< 0.0025 

< 

X 

< 

< 

< 

0.0053 

0.0050 

0.0067 

0.0035 

< 0.0056 

< 0.0048 

< 0.0049 

< 0.0025 

< 0.0034 

Post 

Solid 

Diced 

Air x0.7 

Mass x2 

Feed x1.5 

< 0.0037 

< 0.0039 

< 0.0038 

< 0.0020 

< 0.0027 

< 

X 

< 

< 

< 

0.0054 

0.0050 

0.0084 

0.0036 

< 0.0047 

< 0.0047 

< 0.0047 

< 0.0024 

< 0.0035 

Acrolein 

Pre 

Solid 

Diced 

Air x1.3 

Mass x2 

Feed x1.5 

< 0.0022 

< 0.0023 

< 0.0023 

< 0.0011 

< 0.0015 

< 

X 

< 

< 

< 

0.0032 

0.0031 

0.0041 

0.0021 

< 0.0034 

< 0.0030 

< 0.0030 

< 0.0015 

< 0.0021 

Post 

Solid 

Diced 

Air x0.7 

Mass x2 

Feed x1.5 

< 0.0023 

< 0.0023 

< 0.0023 

< 0.0012 

< 0.0016 

< 

X 

< 

< 

< 

0.0032 

0.0031 

0.0052 

0.0022 

< 0.0029 

< 0.0029 

< 0.0028 

< 0.0015 

< 0.0021 

27
 

 

    

    

    

    

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 Gas 

Fire 

Stage Bookcase Sofa Cable 

Formaldehyde 

Pre 

Solid 

Diced 

Air x1.3 

Mass x2 

Feed x1.5 

< 0.0023 

< 0.0025 

< 0.0024 

< 0.0012 

< 0.0016 

< 

X 

< 

< 

< 

0.0034 

0.0033 

0.0044 

0.0023 

< 0.0036 

< 0.0032 

< 0.0032 

< 0.0016 

< 0.0022 

Post 

Solid 

Diced 

Air x0.7 

Mass x2 

Feed x1.5 

< 0.0024 

< 0.0025 

< 0.0025 

< 0.0013 

< 0.0017 

< 

X 

< 

< 

< 

0.0035 

0.0033 

0.0055 

0.0024 

< 0.0031 

< 0.0031 

< 0.0030 

< 0.0016 

< 0.0023 

The values in Table 11 are the values from Table 10 divided by the notional yields from Table 3. 

Thus the uncertainties are the combined uncertainties from those two tables. 

Table 11. Fractions of Notional Yields. 

Gas 

Fire 

Stage Bookcase Sofa Cable 

CO2 

Pre 

Solid

Diced 

Air x1.3 

Mass x2 

Feed x1.5 

 0.83 ± 5 % 

0.86 ± 6 % 

0.96 ± 3 % 

0.92 ± 9 % 

0.49 ± 12 % 

0.96 ± 

X 

0.47 ± 

0.34 ± 

0.40 ± 

13 % 

9 % 

9 % 

18 % 

0.66 ± 28 % 

0.63 ± 7 % 

0.56 ± 6 % 

0.55 ± 7 % 

0.57 ± 4 % 

Post 

Solid 

Diced 

Air x0.7 

Mass x2 

Feed x1.5 

0.21 ± 39 % 

0.17 ± 3 % 

0.12 ± 10 % 

0.18 ± 11 % 

0.16 ± 10 % 

0.29 ± 

X 

0.18 ± 

0.12 ± 

0.14 ± 

11 % 

14 % 

22 % 

11 % 

0.16 ± 13 % 

0.15 ± 12 % 

0.10 ± 2 % 

0.19 ± 10 % 

0.23 ± 3 % 

CO 

Pre 

Solid 

Diced 

Air x1.3 

Mass x2 

Feed x1.5 

< 0.0010 

< 0.0011 

< 0.0010 

< 0.0005 

< 0.0007 

0.021 ± 

X 

0.019 ± 

0.008 ± 

0.002 ± 

14 % 

42 % 

35 % 

92 % 

0.066 ± 17 % 

0.068 ± 10 % 

0.053 ± 11 % 

0.053 ± 10 % 

0.049 ± 3 % 

Post 

Solid 

Diced 

Air x0.7 

Mass x2 

Feed x1.5 

0.057 ± 46 % 

0.037 ± 22 % 

0.058 ± 22 % 

0.052 ± 17 % 

0.045 ± 10 % 

0.115 ± 

X 

0.134 ± 

0.042 ± 

0.115 ± 

6 % 

8 % 

69 % 

14 % 

0.032 ± 15 % 

0.028 ± 11 % 

0.074 ± 21 % 

0.039 ± 12 % 

0.067 ± 3 % 

28
 

 

 

      

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Gas 

Fire 

Stage Bookcase Sofa Cable 

HCN 

Pre 

Solid 

Diced 

Air x1.3 

Mass x2 

Feed x1.5 

< 0.032 

< 0.034 

< 0.033 

< 0.016 

< 0.023 

< 

X 

0.0164 ± 

< 

< 

0.014 

34 % 

0.018 

0.009 

< 0.071 

< 0.062 

< 0.063 

< 0.031 

< 0.043 

Post 

Solid 

Diced 

Air x0.7 

Mass x2 

Feed x1.5 

< 0.033 

< 0.035 

< 0.035 

< 0.018 

< 0.024 

0.0421 ± 

X 

0.0454 ± 

0.0298 ± 

0.0505 ± 

37 % 

23 % 

23 % 

17 % 

< 0.061 

< 0.060 

< 0.060 

< 0.032 

< 0.045 

HCl 

Pre 

Solid 

Diced 

Air x1.3 

Mass x2 

Feed x1.5 

< 0.55 

< 0.59 

< 0.56 

< 0.28 

< 0.40 

< 

X 

< 

< 

< 

0.30 

0.28 

0.38 

0.20 

0.90 ± 36 % 

0.90 ± 18 % 

0.75 ± 14 % 

0.58 ± 20 % 

0.73 ± 13 % 

Post 

Solid 

Diced 

Air x0.7 

Mass x2 

Feed x1.5 

< 0.58 

< 0.59 

< 0.58 

< 0.31 

< 0.41 

< 

X 

< 

< 

< 

0.30 

0.29 

0.48 

0.21 

0.41 ± 29 % 

0.43 ± 19 % 

0.43 ± 14 % 

0.42 ± 16 % 

0.70 ± 12 % 

29 
This page intentionally left blank 

30 
V. DISCUSSION 

A. OVERALL TEST VALUES 

The principal outcome of this series of tests is a well-documented set of combustion product 

yields. This includes the numerical values themselves, the apparatus conditions under which 

they were obtained, the uncertainty in their calculated values, and the repeatability of the tests. 

Next most important is a determination of the extent to which the toxic gas yields are affected by 

variations in the test protocol that are reasonable in light of possible variations in combustion 

conditions in fires involving the intact products. 

Third, it is important to evaluate the quality of the derived knowledge in the context of its 

intended use. The yield information would be used with a computational fire model (zone or 

CFD) to generate the time-dependent environment generated by a fire. Equations such as those 

in ISO 135719

 would then be used to assess whether the combination of occupancy design, 

contained combustibles, and occupant/responder characteristics lead to the desired level of life 

safety. 

The documentation of the yields has been provided in the earlier sections. The following 

examines the context and quality of the results. 

B. SPECIMEN PERFORMANCE AND TEST REPEATABILITY 

1. General observations 

The bookcase and cable specimens were relatively easy to handle, but the sofa material proved to 

be more challenging. First, the low density of the foam made diced pieces prone to blowing 

around to the degree that we were never successful in conducting a test of the diced material 

without some fraction of the specimen blowing out of the sample boat and into the hot part of the 

furnace. Therefore, we do not report any results for diced sofa material. Second, the low density 

resulted in a relatively large specimen, one that just fit the dimensions of the furnace. Therefore, 

it was not possible to double the mass loading; instead we examined the effect of halving the 

mass loading. The third challenge with the foam was that once ignited, its high flammability 

resulted in a flame spread rate that exceeded the feed rate into the furnace. Thus, the flaming and 

initial decomposition took place upstream of the furnace (Figure 8). When ignited, polyurethane 

foams are known to undergo decomposition into TDI, which burns off initially, and a polyol 

residue, which requires more thermal input before it ignites.31 Therefore, during the majority of 

the tests, there were actually two flame zones, one upstream of the furnace resulting from the 

combustion of the TDI, and one well within the furnace resulting from the combustion of the 

polyol. The products from the first flame pass through the second one, possibly undergoing 

further reaction, and then the products of both flames travelled together into the dilution and 

sampling chamber. 

31 
Figure 8. Close-up of the sofa specimen burning upstream of the furnace 

A similar two-stage reaction can be seen for the bookcase specimens. A moderate amount of 

residue is left behind after flaming combustion, and this material continues to be exposed to high 

temperatures downstream from the flame, potentially producing additional products in 

proportion to how much residue is present in the post-flame region. This contribution may rise 

as the experiment progresses due to the increasing length of the residue in the downstream 

section of the furnace, and due to the chemistry of the residue differing from that of the virgin 

specimen. 

2. CO2 and CO 

Figure 9 shows a typical record for a single experiment. Several important features can be 

observed. The relatively larger spike in CO at the start of the test is the result of an instantaneous 

or impulse release of CO as the specimen first ignites, broadened by the characteristic mixing 

time of the dilution chamber. (If modeled as a perfectly-stirred reactor, the chamber has a time 

constant of 15 s, resulting in a decay time of a little over 2 minutes to reach 1 % of the initial 

value.) Because the intent of this apparatus is to determine the “steady state” generation of toxic 

gases, this initial time period is therefore discarded from the analysis. A similar peak in gas 

concentration can often be found at the end of the experiment, which we attribute to a) the lack 

of additional unburnt material to conduct heat away from the fire, and b) the end face of the 

specimen becoming involved in the fire, increasing the surface area and fire size. Therefore the 

period of interest for determining the “steady state” production lies between these two peaks. 

(Note that the mass loss rate may or may not be higher during ignition and extinction; if it is then 

the yields are somewhat underestimated.) 

32 
However, as can be seen in Figure 9, the gas concentrations continue to vary between the 

ignition and extinction times, more so than allowed by the ISO/TS. We examined the influence 

of the data window selected for averaging on the reported value, and fond it to be considerably 

smaller than the repeatability-related uncertainty. Because of the mixing chamber broadening of 

instantaneous events, several hundred seconds of data were used. 

As intended, changing the temperature and equivalence ratio caused a dramatic decrease in CO2 

yields. In all comparable cases the yield decreased by a factor of 3 to 4, for example with the 

bookcase material from 1.4 to 0.3. At the same time, this caused a substantial increase in CO 

yields for the bookcase and sofa materials, but generally a decrease in CO yields for the cable 

material (about a factor of 2). For the bookcase material, the CO was below the detection limit 

under well ventilated conditions, but around 0.05 for post-flashover conditions, increasing by at 

least a factor of 50. For the sofa material, the CO yield increases by a factor of 5 under 

postflashover conditions, to about 0.14. 

The other variations we examined produced relatively minor changes to the CO and CO2 yields 

when compared to their corresponding well ventilated and postflashover conditions. The biggest 

changes in CO2 yields come when the sofa material is burned under well-ventilated conditions at 

half the mass loading, causing the yield to fall by 65 %. When the cable material was fed at the 

higher feed rate, its CO2 yield increased by 45 %. 

0 

0.2 

0.4 

0.6 

0.8 

1 

1.2 

1.4 

1.6 

Volume Fraction CO2 (%) 

0 

500 

1000 

1500 

2000 

2500 

3000 

Volume Fraction CO ( 

L/L) 

0 200 400 600 800 1000 1200 

Time (sec) 

Figure 9. Measured CO (dotted) and CO2 (solid) Volume Fractions in the Dilution

Chamber When Burning a PVC-clad Electrical Cable. Rectangles indicate the 

time period from which the average volume fraction is determined. 

The biggest changes in CO yield were for the sofa material burned under well ventilated 

conditions, where increasing the feed rate decreased the CO yield by 90 %, and for the cable 

33 
material under postflashover conditions, where a further increase in the equivalence ratio 

(decrease in air) resulted in the CO yield more than doubling. This effect was much lower for 

the other two specimen types. In looking at the effects of variations on the standard conditions 

no strong trends emerge—the degree and direction is specific to specimen type and fire stage. 

In terms of repeatability, most scenarios resulted in CO2 yields that were repeatable to under a 

10 % standard deviation. For those that had a higher variability, the cause was usually one of the 

three runs having substantially different gas yields, all other things being essentially equal. For 

example, for the bookcase material at standard post-flashover conditions (coded b-1-825-2-40-1 

in Table 4 and Table 7, the first run has considerably higher gas concentrations than the second 

and third, even though masses, flow rates, and equivalence ratios are all very close. Figure 10 

shows the raw data from these three experiments, and it is clear that one of them simply 

produced more CO2, (and CO), even though the mass loss and equivalence ratio were nearly 

identical to those in the other tests. 

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0 200 400 600 800 1000 1200 1400

CO2 Volume Fraction

%

Time (sec)

Figure 10. Raw data from Bookcase Material Test b-1-825-2-40. 

The other condition with high variability in CO2 yield was the cable material burned under 

standard well ventilated combustion. Again, the data in Table 6 reveals that, all other things 

being equal, the measured mass loss rate for the second experiment was considerably lower than 

in the other two, for the same gas concentrations, resulting in higher yields. 

The variability of CO yields was somewhat higher, averaging around 20 % for the bookcase, 

20 % to 40 % for the sofa (post- and pre-flashover respectively), and 10 % for the cable. If the 

highest variable yields from the sofa are omitted, then the average variability falls to 5 % and 

34 
26 % for postflashover and well ventilated respectively. The high variability in the sofa values 

comes mainly from two cases: well ventilated with the feed rate increased 50 %, and 

postflashover with the mass load halved. In the first case, the cause is very low CO yields, close 

to the limit of detection (below, in fact, for one of the triplicates). This is a case of “small 

differences between small numbers have large relative importance.” In the postflashover case, 

looking back to Table 5 and Table 8, we see that at the time of the experiments, the results were 

sufficiently variable that we conducted additional runs. 

3. HCl and HCN 

HCN was detected via FTIR and was only observed in the sofa tests. Under well ventilated 

conditions, it was only observed when the primary air flow was increased by 30 %. It was 

observed in only 2 of the 3 replicate experiments, and at concentrations only slightly over the 

minimum detection limit. HCN was consistently observed under postflashover conditions, 

resulting in yields that were 2 to 5 times greater than the minimum detection limit and nearly 3 

times the single yield measured from well ventilated combustion. The only other variation to 

have a significant effect was reducing the mass loading: as with the CO2 and CO, halving the 

mass of foam resulted in a considerable decrease in yield (30 % here). 

HCl was detected via FTIR and was only observed in the cable tests. Under well ventilated 

conditions, it was observed at yields between 0.2 and 0.3, which are close to the notional yields. 

The highest yield of HCl is obtained when the specimen is diced, while the lowest occurs when 

the fuel load is doubled. Under postflashover conditions, the yield is reduced by 40 %. The only 

operational variation that has an effect is to increase the feed rate by 50 %, which restores the 

yield to the well-ventilated value. 

C. MEASURED VS. NOTIONAL VALUES 

During sustained and complete combustion, the yield of CO2 should approach its notional values, 

since CO2 is a marker for combusted carbon. Under well ventilated conditions, the sofa material 

most closely approaches complete combustion with a yield of CO2 that is 96 % of the notional 

yield. Under the same conditions, the yield of CO2 from the bookcase material reaches 83 % of 

the notional yield, but this rises to 96 % when the flow of air is increased by 30 %. By this 

measure, the cable material experiences the least complete combustion, its yield of CO2 reaching 

a maximum of 66 % of the notional yield under well ventilated conditions. Under postflashover 

conditions, the CO2 yields for all specimens and conditions range from 10 % to 29 % of the 

notional yields. 

The yields of CO from all the specimens ranged from 0.003 to 0.166. These values are 

consistent with combustion ranging from fuel-lean to fuel-rich32 and are in some cases approach 

the 0.2 value expected of postflashover fires.14 

The yields of HCl from the cable specimens approach their notional values. The deficit may 

reflect scavenging by the calcium carbonate filler in the cable jacket or wall losses. The 

detection limited yields of HCl from the sofa specimens was around 30 % of the notional yield 

under all conditions. The detection limited yield of HCl from the bookcase was around half the 

notional yield. 

Yields of HCN from the sofa are between 2 % and 5 % of their notional values. The highest 

relative yield is found at postflashover conditions with the feed rate increased by 50 %. 

35 
D. SPECIES SAMPLING AND MEASUREMENT 

1. Species Measurement Using FTIR Spectroscopy 

FTIR spectroscopic analysis of combustion products has become fairly common in fire research 

laboratories. However, that does not mean that its use is straightforward. The data from a recent 

round robin involving FTIR measurement of toxic combustion products from a standardized 

apparatus showed interlaboratory variations of up to an order of magnitude. There are 

documents under development in ISO TC92 SC1 and SC3 to standardize the implementation. 

We were able to obtain usable information using this technique. There are a number of lessons 

emerging from this test series that can provide useful input to these efforts, such as the 

following: 

	 The application of FTIR spectroscopy to fire testing requires the constant attention of an 

experienced professional at a level well beyond the demands of the more traditional fire 

test instrumentation. 

	 To maximize the opportunity for obtaining time resolved concentration data, we selected 

a small volume cell of short optical path length and operated without a soot filter. While 

some cleaning was necessary, it was not a major impediment. However, the short path 

length did limit the sensitivity, and moderated our ability to determine toxicologically 

important levels of the major gases. 

	 For future work, a longer path length should be considered. Ideally the test method 

achieves steady state in which case the response and residence time of the cell is 

unimportant. In reality, when real specimens are burned there are fluctuations on the 

order of seconds. This is ameliorated by the well-mixed nature of the dilution and 

sampling chamber, which has a characteristic time on the order of 60 sec. 

	 A heated sample line (as recommended in the SAFIR report33 and ISO 1970234) enabled 

quantitative collection of HCl, a compound that is generally regarded as difficult to 

determine. 

E. IMPORTANCE OF UNDETECTED GASES 

The equations in ISO 13571 include provision for additional gases to be included in estimating 

the time available for escape or refuge from a fire: HBr, HF, SO2, NO2, acrolein (C3H4O) and 

formaldehyde (H2CO). There was no Br, F, or S in any of the products examined in this project, 

so the first three of these gases were not expected. The presence of the latter three was not 

detected, thus establishing the upper limits of their presence at the volume fractions listed in 

Table 2. 

To put the potential contributions of the sensory irritant gases (HCl, NO2, acrolein, and 

formaldehyde) in context, we use the equations in ISO 13571 for calculating the Fractional 

Effective Dose (FED) for the narcotic gases, CO2 and CO, and the Fractional Effective 

Concentration (FEC) for the four sensory irritant gases. 

36 
 

 

 

 

 

 

 

The FED equation is: 

 CO  2 exp   , t 2 t 2 2.36  5      CO HCN FED    t  6 t t1 35000 t1 1.2 10  

where Δt is the exposure interval in minutes. 

The FEC of the four irritant gases were estimated from their volume fractions and the 

incapacitating levels in ISO 13571 (FHCl, etc.). The results are compiled in Table 12. 

The FEC equation in ISO 13571 is: 

    HCl  HBr  HF SO2 NO 2  acrolein formaldehyde  irritant FEC = 

F F F F F F F HCl HBr HF SO 

       F 2 NO 2 acrolein formaldehyde Ci 

Table 12. Limits of Importance of Undetected Toxicants 

Volume fraction (μL/L) Fractional FEC Contribution 

HCl NO2 C3H4O H2CO HCl NO2 C3H4O H2CO 

Incapacitating 

Level 1000 250 30 250 

Bookcase < 20 < 40 < 20 < 40 < 0.02 < 0.16 < 0.66 < 0.16 

Sofa < 20 < 40 < 20 < 40 < 0.02 < 0.16 < 0.66 < 0.16 

Cable 4470 < 40 < 20 < 40 0.82 < 0.03 < 0.12 < 0.03 

to 1140 < 40 < 20 < 40 0.54 < 0.08 < 0.31 < 0.08 

It stands out that the FEC contribution from acrolein is as much as two-thirds of an 

incapacitating level. This is because (a) the limit of detection is close to the listed incapacitating 

level and (b) the incapacitating level is very low. While there is agreement among experts that 

this value of 30 μL/L is reasonable, there are data that suggest strongly that this is unnecessarily 

conservative. Kaplan and co-workers exposed individual baboons to various concentrations of 

acrolein in air.35 At the end of 5 min, each baboon was given a signal and could perform an 

action that led to escape from the test chamber. The baboons exposed at up to 500 μL/L escaped 

and survived. Those exposed to higher levels escaped, but died later. These data suggest that 

people should be able to accommodate a nearly instantaneous exposure to, e.g., at least 300 μL/L 

without becoming incapacitated. If we increase the incapacitating level of acrolein to 250 μL/L, 

the relative contribution to FEC become those in Table 13. In this case the relative importance 

of acrolein falls below 0.05 when other irritants are detected. 

37 
 

 

 

 

 

 

 

Table 13. Limits of Importance of Undetected Toxicants with Adjusted Acrolein 

Contribution 

Volume fraction (μL/L) Fractional FEC Contribution 

HCl NO2 C3H4O H2CO HCl NO2 C3H4O H2CO 

Incapacitating 

Level 1000 250 250 250 

Bookcase < 20 < 40 < 20 < 40 < 0.05 < 0.38 < 0.19 < 0.38 

Sofa < 20 < 40 < 20 < 40 < 0.05 < 0.38 < 0.19 < 0.38 

Cable 4470 < 40 < 20 < 40 0.92 < 0.03 < 0.02 < 0.03 

1140 < 40 < 20 < 40 0.74 < 0.10 < 0.05 < 0.10 

Where specimens like the bookcase and sofa produce narcotic gases, CO and HCN, and irritants 

are below the limits of detection, the narcotic gases are the primary contributors to 

incapacitation. Assuming that the irritant gases are present in just under the limits of detection, 

in order for them to reach an incapacitating concentration, the relative concentration of CO 

would be incapacitating in a few minutes; the relative concentration of HCN would be 

incapacitating in under a minute. 

38 
VI. CONCLUSION 

This paper reports toxic gas yield data for specimens cut from three complex combustibles: a 

bookcase, a sofa, and residential electrical power cable. The physical fire model used was the 

ISO/TS 19700 tube furnace. This apparatus is intended primarily for thermoplastics, but has 

some limited ability to test more complex assemblies. By design the equivalence ratio can be 

varied from fuel-lean to fuel-rich in order to simulate both well ventilated and postflashover fire 

stages. In addition to performing the tests under the standard conditions, this work examined the 

effect of varying the air flow rate, fuel feed rate, fuel load, and the effect of dicing the test 

specimens, to estimate the effects of the test variables and the conformation of the test specimen. 

The findings were as follows: 

	 For the specimen types we investigated, the gas concentrations did not reach a steady 

state as defined in the technical specification. Therefore, we had to verify that our 

selection of time interval did not bias the result. 

	 The selection of data from the middle of the run, and the assumption of steady state may 

result in underestimation of the gas yields, as the burning rate appears higher at the 

beginning and end of the runs. In the absence of real time mass loss data, it might be 

more reliable to integrate the gas concentrations and convert to the mass of gas evolved. 

	 The combustion environment varies along the length of the furnace. At the peak 

temperature (925 K), the radiant flux is over 50 kW/m2

, with sharp fall-offs upstream and 

downstream. For specimens that burn in multiple stages (e.g. polyurethane), the less 

flammable component may proceed downstream of the initial reaction zone, and 

experience a higher equivalence ratio and temperature. 

	 Test specimens with high linear burning rates overtake the feed mechanism, therefore 

having a higher mass loss rate than intended. This is not addressed in the Technical 

Specification. 

	 The CO2 yields were fairly repeatable and under well ventilated conditions represented 

much of the carbon in the specimens. The cable had the lowest fraction of carbon 

converted to CO2 and a relatively higher yield of CO, indicating incomplete combustion 

even under well ventilated conditions. Under postflashover conditions, the CO2 yields 

decreased considerably, with only 10 % to 30 % of the carbon in the fuel converted to 

CO2. 

	 The CO yields are less repeatable, and there is no direct correlation between the 

repeatability of the CO2 and CO yields. Between well ventilated and postflashover 

conditions, CO yields increased by a factor of 5 for the bookcase and sofa materials, but 

decreased by a factor of 2 for the cable materials. Only in the case of the sofa material 

under postflashover conditions do the CO yields approach the value of 0.2 found in realscale post-flashover fires. 

	 The sum of the CO2 and CO yields frequently accounted for half or less of the carbon 

originally in the specimen. Presumably, the post-test residue is enriched in carbon. As a 

result, the gaseous combustion products cannot be used to estimate the mass burning rate. 

39 
	 The HCN yields were below the limits of detection for the bookcase and cable 

specimens. Even for the sofa materials, only one of the four well ventilated test 

conditions (increased air flow) resulted in sufficient HCN for detection. Under 

postflashover conditions HCN was detected at yields around 4 times the detection-limited 

yield. This represented 3 % to 5 % of the available nitrogen in the polyurethane foam. 

	 The HCl volume fractions were below the limit of detection for the bookcase and sofa 

specimens. For the cable specimens, they were fairly repeatable and the yields 

approached 90 % of the notional yield under well ventilated conditions. Under 

postflashover conditions, the yields of HCl from the cable specimens were under half the 

notional yield, indicating that the chlorine was either trapped in the residue or deposited / 

scavenged somewhere else in the apparatus upstream of the FTIR. Preserving the residue 

for post-test elemental analysis would have helped address the fate of the unaccountedfor HCl. 

	 The yields of NO, NO2, acrolein, and formaldehyde were all below their respective limits 

of detection. 

	 Small changes in operating conditions such as air flow, feed rate, and fuel loading did not 

consistently affect the yields of the measured gases, comparing effects on a single gas 

between specimen types or between gases for a single specimen type. 

	 Dicing the specimens had no significant effect, other than allowing low-density materials 

to be displaced from the specimen boat. 

	 The sensitivity of the short optical path FTIR cell limited the precision of this 

examination. However, there was sufficient information to assess the toxicological 

significance of the variations in the test procedure. 

	 Calculation of the contributions of the gases to incapacitation of people who might be 

exposed to these environments showed: 

o	 For the bookcase material, incapacitation would result from inhalation of CO and 

CO2. 

o	 For the sofa material, incapacitation would result from inhalation of CO and 

HCN. 

o	 For the cable material, incapacitation would result from exposure to HCl. 

If the CO yield were at the expected postflashover value of 0.2, 

o	 For the bookcase material, incapacitation would result from inhalation of CO and 

CO2. 

o	 For the sofa material, incapacitation would result from inhalation of CO and 

HCN. 

o	 For the cable material, incapacitation would result initially from HCl, and then 

from CO after a time on the order of 10 minutes, depending on the quantity of 

material burned. 

40 
VII. ACKNOWLEDGMENTS 

The authors express their appreciation to Mike Selepak, Kyle Geder, Jonathan Levin, and Adam 

Schwartz for their assistance in performing the tests and to Jason Averill for the apparatus 

assembly. 

41 
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42 
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