Technical Report Documentation Page 

1. Report No. 2. Government Accesston No. 

DOT/FAA-AM-8 6- 

4. Title and Subtitle 

INMLATION TOXICOLOGY: V. EVALUATION OF RELATIVE 

TOXICITY TO RATS OF THERMAL DECOMPOSITION PRODUCTS 

FROM TWO AIRCRAFT SEAT FIRE-BLOCKING MATERIALS 

7. Author's) Donald C. Sanders, Charles R. Crane, and 

Boyd R. Endecott 

FAA Civil Aeromedical Institute 

P.O. Box 25082 

Oklahoma City, OK 73125 

9. Performing Organization Name and Address 

12. Sponsorrng Agency Name and Address 

Office of Aviation Medicine 

Federal Aviation Administration 

800 Independence Ave., SW. 

Washington, D.C. 20591 

T 

t 

3. Reciplent's Catalog No. I 

5. Report Date 

NOVEMBER 1985 

6. Performlng Organjzation Code 

~~~ 

AAM-114 

8. Perforrnlng OrganIration Report NO. 

FAA-AM-85- 

10. Work Unlt No. (TRAIS) 

11. Contract or Grant No. 

13. Type of Report and Perlod Covered 

OAM Report, October 1983 

to September 1984 

-__ 

14. Sponsortng Agency Code 

Task AM-B-84-TOX-43 

15. Supplementary Notes 

L 

Ah&.& -t. G,b*k* - 17- + 4 

This work was performed under task AM-B-84-TOX-43. 

16. Abstract 

Two fire- blocking layer (FBL) materials, designed to delay the thermal decomposition 

of polyurethane foam seat cushions during an aircraft cabin fire, were evaluated for 

the relative toxicity of their gaseous combustion products. Each material was thermally decomposed under five distinct thermal environments: two contact temperatures 

(600 and 750 "C) in a horizontal hot tube furnace and three flux levels (2.5, 5.0, 

and 7.5 W/cm2) in a radiant heat furnace. The measured toxicological endpoint was 

time-to-incapacitation (ti) in the albino rat; this endpoint is believed to be the 

most relevant one for assessing smoke hazard in a fire environment. 

In three of the five test environments, Norfab, an aluminized synthetic fabric, 

produced shorter t

i

's--and was thus more toxic--than Vonar, a neoprene foam. 

However, at 2.5 W/cm2 in the radiant furnace system, the Norfab test specimen lost 

only 13 percent of the sample weight and did not incapacitate any of the test animals 

during the exposure period and, at 750 OC (flaming) in the combustion tube assembly, 

Norfab produced longer and more variable ti's than did Vonar. 

Hydrogen cyanide (HCN) was detected in the combustion products from Norfab under all 

test conditions except the 2.5 W/cm2 radiant flux level; no HCN was detected in the 

combustion products from any of the Vonar tests. Since Norfab routinely produced 

lower concentrations of carbon monoxide than did Vonar under all test conditions, 

the greater apparent toxicity (shorter ti's) of Norfab would appear to be caused 

by the cyanide production. - 

7. Key Words 

Enhalation toxicology; fire- blocking 

Layers; cabin fires; seat cushions; 

time- to- incapacitation; animal 

zxposure systems 

18. Distribution Statement 

Document is available to the public 

through the National Technical 

Information Service, Springfield, 

VA 22161. i 

9. Security Classif. (of this repart) 20. Security Classif. (of this page) 22. Price ' 21. No. of Pages 

Unclassified Unc3assif ied 1 13 

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form DOT F 1700.7 03-72) Reproduction of completed page authorized 

INHALATION TOXICOLOGY: V. EVALUATION OF RELATIVE 

TOXICITY TO RATS OF THERMAL DECOMPOSITION PRODUCTS 

FROM TWO AIRCRAFT SEAT FIRE-BLOCKING MATERIALS 

INTRODUCTION 

The ubiquitous flexible polyurethane foam has perhaps achieved wider 

acceptance by the transportation industry for upholstering seats in various 

mass transit vehicles than any other commercial cushioning polymer. Aircraft 

manufacturers, in particular, have been appreciative of polyurethane's light 

weight, excellent mechanical characteristics, and low cost. Indeed, the 

seat cushions,backs, and headrests of an average 200-seat commercial transport 

aircraft cabin contain about 640 f t3 (1 , 200 lb) of f ire-retarded polyurethane 

foam (6). Unfortunately, polyurethane is thermally quite sensitive and 

begins to decompose at temperatures as low as 250 Qc,producing relatively 

high yields of combustible and toxic gases and posing a potential threat to 

safety in fire situations aboard aircraft, in subway vehicles, or in any other 

closed environment. Fire retardants that can be incorporated into the foam 

itself are only marginally effective in suppressing combustible vapor formation when polyurethane foam is exposed to a sustained high heat flux, and the 

possible substitutes for polyurethane that can be made sufficiently fire 

resistant to inhibit flame propagation and flashover (phenolics, polyimides, and 

polybenzimidazoles) all suffer from prohibitive limitations of comfort, durability, and cost (6). 

With the options of fire retardants and substitute cushioning materials 

considered ineffective or impractical, safety considerations have led to the 

fire- blocking-layer (FBL) concept. This involves covering the thermally 

sensitive polyurethane foam cushions with a layer of a fire -resistant, highchar-yield polymer that would be slowly consumed but would delay the fire 

involvement of the polyurethane. Tests conducted by the Federal Aviation 

Administration (FAA) have shown that certain FBL materials are effective in 

containing (or delaying the release of) combustible molten and gaseous polyurethane products inside the cushion, thereby increasing passenger escape time 

and thus survival in a potential fire situation (1,5,6). The new flammability 

performance requirements for aircraft seat cushions are based on the performance 

attained by FBL construction (4). 

The purpose of this study was twofold: (i) to examine, under defined 

laboratory test conditions, the relative toxicity of the combustion products 

of two of these FBL materials and (ii) to make an initial evaluation of a 

new combustion/exposure assembly that decomposes test samples by radiant heat 

from one side only, a directional heat flux likely to be encountered by panels, 

seat cushions, and other flat surfaces during a cabin fire. 

Both the FBL materials examined had been found to provide similar thermal 

protection in both small-scale laboratory tests and large -scale (Cabin Fire 

Simulator) studies (1,6). One material, Vonar, is a high-char-yield neoprene 

foam that cools the heated zone by emission of water vapor as it decomposes. 

1 
This foam is relatively heavy, requiring about 4 lb to cover the polyurethane 

foam cushion and seat back in an aircraft seat. The second material, Norfab, 

is a composite fabric bonded to an aluminum foil layer that slows flame 

propagation by containing the molten polyurethane inside the seat cushions. 

It carries a lesser weight penalty than Vonar (6). The acceptable performance 

of these materials as fire- blocking layers made it desirable to determine 

whether any unusual toxic hazard was likely to arise from their use in 

transport aircraft. 

We have noted previously that marked variations in the composition and 

and toxicity of combustion gases can occur when polymeric materials are 

decomposed under different thermal conditions. The combustion/exposure system 

used at the Civil Aeromedical Institute for several years pyrolyzes sample 

material inside a quartz combustion tube encircled by a small furnace and has 

enabled us to test materials at different temperatures, as well as under flaming 

or nonflaming conditions (2,3). Radiant heat from this furnace impinges on 

the sample from the perimeter of.the combustion tube, and conductive heat is 

transferred to the sample through the quartz combustion boat, thereby causing 

rapid and complete pyrolysis. These laboratory pyrolysis conditions may or 

may not be duplicated in a "real" cabin fire. In a large -scale fire, flat ' 

surfaces such as seat cushions and panels are more likely to be exposed 

initially to unidirectional radiant heat from some single source than to the 

omnidirectional radiant and conductive heating conditions found in the 

combustion tube. 

To duplicate, as closely as possible, these hypothetical "real" fire 

conditions and thus to assess more accurately the potential toxic hazard of 

the FBL materials, we designed and constructed a combustion/exposure assembly 

that pyrolyzes flat materials by radiant heat directed onto the upper surface 

of the sample only. The relative toxicity of the combustion gases was measured 

by determining time-to-incapacitation (ti) in the laboratory rat, the same 

endpoint that was used in the older (and smaller) combustion tube assembly. 

In this study, we tested equivalent samples of the same FBL materials 

in both systems to determine the effect of the two pyrolysis methods on 

relative toxicity. Sample equivalency for the two combustion/exposure 

systems, which differ over twentyfold in volume, was based on the ratio of 

sample surface area to chamber volume, instead of the more familiar weight-tovolume concept, a modification based on the end-use requirement for equal 

surface areas of each of the FBL materials. 

MATERIALS AND TEST SYSTEMS 

Animals. Albino rats of Sprague-Dawley origin were obtained from the 

Charles River Breeding Laboratories, Wilmington, MA. They were ordered in a 

weight range of 100 to 120 g and were held in isolation for 8 days prior 

to use. All were maintained for 4 days on drinking water containing 1.5 g/L 

of sulfathiazole, then normal tap water for the remaining 4 days of isolation. 

Rats were fasted overnight before testing to establish an equivalent 

metabolic state, and each animal was weighed and marked with an identifying 

color code just before use. 

2 
Test Materials. The two materials investigated were previously determined 

to be acceptable when tested as fire- blocking layers over polyurethane foam 

cushions (1,6). Material descriptions are as follows. 

Norfab llHT-26-A1: This material is a woven composite of 70 percent 

Kevlar (poly(p-phenyleneterephthalamide)), 25 percent Nomex (poly(imin0-1, 

3-p~~~y~~~eiminoc~~bonyl-1,3-phenylenecarb0nyl)), and 5 percent Kynol (novolak, 

a phenol-formaldehyde polymer). One side of the fabric is bonded to an 

aluminum foil layer; the finished material weight is 0.40 kg/m2. This composite 

is representative of the aluminized, char-forming, high-temperature-resistant, 

reradiation- cooling type of materials. The supplier was Amatex Corp., 

1032 Stonebridge St., Norristown, PA. 

Vonar-3: This material is a 3/16-inch-thick neoprene (polychloroprene) 

foam attached to a cotton fabric backing, with Al(OH)S added as a fire retardant. Vonar is representative of the transpirational and dissipative cooling 

class of materials. Finished weight is 0.91 kg/m2. The product was supplied 

by Chris-Craft Industries, 1980 E. State Street, Trenton, NJ. 

Combustion/Exposure Assemblies. Two animal exposure systems were used in 

this study, a 265-L and a 12.6-1, system. The larger, recently constructed 

system was equipped with a radiant heat furnace designed to deliver heat to 

only the upper surface of the sample. The older, smaller system utilized a 

combustion tube assembly enclosed by a cylindrical heating unit that provided 

omnidirectional radiant heat around the perimeter of the tube and conductive 

heat through the tube wall. 

265-L System: A diagram of this unidirectional radiant heat system is 

shown in Figure 1. The larger chamber, in which the animals were exposed, 

was constructed of polymethylmethacrylate (PMMA) and had an internal volume 

of 203 L. The smaller 42-L plenum was positioned above the combustion assembly 

to allow cooling and dilution of the hot combustion gases before entry into 

the animal chamber. The plenum was constructed of polycarbonate (for heat 

resistance), and the chambers were connected by two 7-cm-diameter PMMA tubes. 

A flexible tube allowed the continuous circulation of air from the floor of 

the animal chamber to the combustion assembly, underneath and around the decomposing test sample, into the plenurn, and hack into the animal chamber. The 

experimental animals were contained inside the animal chamber in four individual 

20-cm rotating cages mounted on a motor-driven shaft. Perimeter velocity for 

the rotating cages was 6.4 cm/s. 

The combustion assembly was constructed of stainless steel with triangular end sections; full-length quartz windows allowed radiant heat from 

four 2,000-watt quartz lamps (two on each side) to impinge on the sample 

surface at approximately 45" angles. In use, the radiant heat flux reached 

its specified level within 30 seconds of initiation. This rapid equilibrium 

was attained by using a graduated heating schedule, with an initially high 

and gradually decreasing power setting that allowed the rapid development 

and maintenance (within t 0.2 W/cm2) of the selected heat flux level. All 

radiant heat measurements were made at the center of the sample position with 

the sample tray removed. The maximum sample size accepted by the combustion 

assembly was 7.6 by 22.9 cm (3 by 9 in) ; the assembled syscem had a total 

volume of 265 L. 

3 
12.6-L System: The smaller animal exposure system has been described 

in detail in previous publications (2,3).; a diagram of the specific configuration used in this study is shown in Figure 2. Briefly, it consisted 

of a PMMA box containing a motor-driven rotating cage with compartments 

for three rats; perimeter velocity for this cage was also 6.4 cm/s. A 

recirculating blower forced chamber air through the combustion tube and over 

the sample, then moved the combustion gases into the animal chamber. Two 

425-wattY semicylindrical heating units encircled the combustion tube, providing radiant (and conductive),heat for decomposition of the test sample. 

The total system volume was 12.6 L. 

Atmosphere Analysis and Control. Similar analytical protocols were used 

for both systems. Periodic samples of the chamber atmosphere were analyzed 

for hydrogen cyanide (HCN), carbon monoxide (CO), and oxygen (02) by gas 

chromatography (GC) during each test. Oxygen was resupplied manually to the 

animal chamber as required to maintain a concentration within 90 percent of the 

ambient level. Air temperatures were monitored with thermocouples mounted in 

the animal chambers, and power to the combustion units routinely was shut off 

after 10 minutes to prevent overheating the chamber air. 

Test sample size for both systems was based on the maximum size (7.6 by 

22.9 cm) accommodated by the sample tray in the radiant heat combustion 

assembly; this 174-cm2 sample, in the 265-L system, equated to a sample-areato-volume loading of 0.66 cm2/L. To obtain an equivalent area-to-volume ratio 

for the 12.6-L system, the surface area (174 cm’) of the larger sample was 

multiplied by the ratio of the relative system volumes: 

Equivalent area = 265 L 12.6 x 174 cm2 = 8.3 cm2 (or a square 2.9 cm on a side). 

Samples of each material with 2.9-cm-long sides were then cut to provide 

equivalent area-to-volume loadings for the 12.6-L system. 

EXPERIMENTAL PROCEDURE 

For tests in the 265-L chamber, fasted albino rats were weighed and 

placed in the individual rotating cages; the chamber cover was replaced and 

connected to the adjoining polycarbonate plenum. The test specimen of 

FBL material (previously conditioned overnight at 50 percent relative humidity) 

was weighed and placed in the sample tray. The system was sealed; the external 

oxygen resupply, the gas sampling, and the temperature monitoring equipment 

were connected; and the power control for the radiant heat assembly was set to 

supply the desired heat flux level. At zero time, the cage rotation motor, 

heater power supply, recirculating fans, and timer were activated simultaneously. The test specimen was observed for the first indication of thermal 

breakdown (melting/smoke) and for ignition. Samples of chamber atmosphere 

were removed manually by syringe and analyzed (by GC) for 02, COY and HCN; 

oxygen was resupplied manually as needed. Time-to-incapacitation (ti) was 

noted when each rat could no longer perfom the coordinated act of walking 

in the rotating cage; i.e., when sliding or tumbling began. When all rats 

were incapacitated, cage rotation was stopped; time-to-death (td) was recorded 

for each rat when visible signs of respiration ceased. 

4 
Tests in the small (12.6-L) chamber were carried out in the same manner 

except for the methods of sample insertion and chamber atmosphere sampling. 

Since the cylindrical heating unit required several minutes to reach a stable 

temperature, the unit was preheated to the desired temperature before 

inserting the sample. The weighed sample was placed in a quartz combustion 

boat and, at time zero, the boat was moved into the center of the heated area 

in the combustion tube. A fraction of the test atmosphere was constantly 

pumped through a closed loop from the animal chamber, through the sampling 

loops on the two GC's, and back into the chamber. Relays that controlled the 

pneumatic sampling valves on the GC were activated every 1.8 minutes for CO 

and 3.6 minutes for HCN; these sampling intervals were the minimum times 

required to elute the respective gas peaks from the GC columns. 

RESULTS AND DISCUSSION 

It should be noted again that the toxicity comparisons between Norfab and 

Vonar that follow are based on equal sample surface areas instead of the 

more common equal weights of materials. The rationale for this choice is that 

an equal area of each FBL material would be required to cover and protect any 

specific surface area of polyurethane foam seat cushions; we feel that this 

end use of the materials dictates equal surface area as the more logical unit 

for relative toxicity comparisons. The equivalent chamber loadings, expressed 

as the ratios of weights of test material loaded (milligrams) to system volume 

(liters), were 26 mg/L for Norfab and 60 mg/L for Vonar. 

The mean observed response times are presented in Table 1 for each material 

and test condition. Statistical precision for the data is indicated by the 

standard deviation (S.D.) and relative standard deviation (rsd) for each set 

of animal responses. Times-to-incapacitation observed for Norfab and Vonar 

ranged from 8.6 to 19.1 min in the 265-L (radiant heat) assembly and from 7.1 

to over 45 min in the 12.6-L (combustion tube) system. Deaths were noted during 

the test period for both materials under all conditions except Norfab at 2.5 

W/cm2 (265 L), a condition that produced incomplete (and minimal) pyrolysis of 

the test specimen. Norfab and Vonar both showed increasing toxicity (shorter ti's) 

with each increase in radiant heat flux when exposed to unidirectional heat in 

the 265-L system, but only Vonar produced a similar response to omnidirectional 

heat in the combustion tube (12.6-L) system. When Norfab was pyrolyzed at 

750 OC (flaming), ti's varied from 17.1 to 36.4 min with two of the six rats 

not incapacitated after 45 min. Norfab's variable behavior at 750 OC contrasted 

with the 600 OC tests, where it produced a mean ti of 7.1 min'with only a 

4-percent rsd. 

The loss in weight of FBL materials pyrolyzed in the 12.6-L system was 

60 to 64 percent of the sample weight .at both 600 and 750 OC, indicating that 

the observed differences in response times between the two conditions were 

more likely due to differences in the composition, not quantity, of the 

combustion products, or to differences in the rates of gas evolution. The 

original design of the radiant heat assembly (265 L) did not permit quantita - 

tive recovery of the sample residues, so comparisons of weight losses between 

the two systems could not be made. At the lowest flux level (2.5 W/cm2), 

however, Norfab samples were only partly decomposed, and were recovered 

essentially intact; the weight loss was only 13 percent of Norfab's preburn 

weight. 

5 
Peak values for CO concentrations are listed in Table 2. Except for 

the 2.5-W/cm2 tests (265 L), the peak CO concentrations differed only slightly 

in magnitude. The rate at which these peak values were attained, however, 

varied with increasing radiant heat flux or temperature. At the higher 

temperatures, sample decomposition was more rapid and peak CO concentrations 

were reached earlier, thereby exposing the rats to high CO levels for a 

greater fraction of the observation period. 

Hydrogen cyanide was detected in the Norfab tests at both temperatures 

in the 12.6-L system. Peak values were 250 ppm at 600 OC, but only 70 ppm at 

750 OC (flaming). Norfab also produced detectable levels of HCN in the 265-L 

system at 5.0 and 7.5 W/cm2, but not at 2.5 W/cm2. Detection of HCN in the 

265-L system was qualitative only. For this initial evaluation of the system, 

chamber air samples were removed manually, by syringe, and injected into the 

GC sample loop. Quantitation of the detected HCN was not possible because 

of the tendency for HCN to dissolve in any condensed moisture on the syringe 

walls and therefore to not be introduced quantitatively into the GC. Vonar 

did not produce detectable quantities of HCN, in either system, under any 

of the test conditions. Analytical values for HCN are shown in Table 3. 

SUMMARY AND CONCLUSIONS 

We have described the testing of two fire- blocking-layer materials, 

Norfab and Vonar, for the relative toxicities of their combustion products, 

in two different laboratory-scale systems. We have studied the characteristics 

of a new 265-L system, in which flat material samples are thermally decomposed 

by radiant heat incident on the top surface only, and .compared the results with 

those from an older 12.6-L system, in which materials are pyrolyzed inside 

a preheated combustion tube assembly. Time-to-incapacitation in the laboratory 

rat was the measured response used to compare the relative toxicity of the 

combustion gases produced from the two materials. 

Because of the intended end use of the fire- blocking materials, we have 

based the relative toxicity for each test system on the animal response times 

obtained when equal surface areas of each material were pyrolyzed. For comparisons between the two combustion systems, we selected sample surface areas 

proportional to the respective system volumes. 

In summary, Vonar proved less toxic (longer ti's) than Norfab in three 

of the five test conditions. The mean ti's for Norfab and Vonar were significantly different at the P.05 level by Student's t-test (7) in the 265-L system 

(at 5.0 and 7.5 W/cm2>, and in the 12.6-L system at 600 OC. In one exception 

(265-L system, 2.5 W/cm'), Norfab lost only 13 percent by weight (21 percent 

of its combustible components) and did not produce an animal response within 

the test period. In the other exception, Norfab produced an unusually wide 

range of response times in the 12.6-L system at 750 OC (flaming). One explanation could be the low concentration of CO produced by this combustion condition. 

We have noted that CO concentrations of 3,000 ppm and below tend to produce not 

only longer ti's, but also increased variation in individual rat response times. 

Also, the low HCN concentration (70 ppm) was present for only the first 

4 to 5 min and probably produced a minimal additional toxic insult. 

6 
The lowest heat flux (2.5 W/cm2) selected for radiant heat pyrolysis 

proved inadequate to decompose Norfab to the extent necessary to produce 

an animal response, at least at the 26-mg/L weight loading. Vonar produced 

incapacitation at the same flux level, but at a weight loading of 60 mg/L, 

a loading that we have considered optimum for testing aircraft cabin materials 

in the older 12.6-L combustion tube system (3). Both FBL materials produced 

reasonable and reproducible ti's, however, at the higher 5.0- and 7. 5-W/cm2 

flux levels. 

At present, we believe the maximum sample size accepted by the radiant 

heat chamber to be adequate, although some extremely lightweight materials may 

prove inadequate with a 7.6- by 22.9-cm sample. To increase the size of the 

combustion chamber to accommodate a larger sample surface area would also 

increase the problems of uniform sample heating, increase the cumulative 

temperature in the animal chamber, and increase the probability of producing 

a flammable gas concentration with subsequent ignition. For most panels, 

floorings, and other flat-surfaced materials, the present sample-size-to-volume 

ratio appears to be an acceptable compromise between versatility and practicality. 

The preliminary evaluation of the two combustion systems has indicated 

certain modifications in equipment and procedures for future studies. We 

have modified the radiant heat combustion assembly to allow the quantitative 

recovery of sample residues; this will enable us to determine the extent of 

sample pyrolysis at different flux levels. We have installed a constant-flow, 

closed-loop air sampling assembly on the 265-L system, which will permit 

automatic, direct sampling at preset intervals and will allow the quantitative 

GC determination of HCN. 

7 
Table 1. Animal Response Times to Combustion Products of Norfab 

and Vonar at 0. 66-cm2/L System Loading Level 

265-L System - Top Radiant Heating Only 

Material Heat Flux 

t . (min) 1 

td (min) 

N Mean S.D. rsd(%) N Mean S.D. rsd(%) - -- --- - 

Norfab 11HT-26-A1 2.5 8 NR* -- --- 8 NR* -- --- 

5.0 16 9.0 1.16 12.9 16 15.4 2.42 15.7 

7.5 20 8.6 1.49 17.4 20 16.8 3.99 23.8 

Vonar-3 2.5 12 19.1 2.93 15.3 12 27.2 5.37 19.8 

5.0 12 12.1 1.39 11.4 12 17.6 3.18 18.0 

7.5 20 10.4 1.02 9.8 20 16.0 3.10 19.3, 

12.6-L System - Combustion Tube Pyrolysis 

Material Furnace 

T ("C> 

t . (min) 1 td (min) 

--- N Mean S.D. rsd(%) --- N Mean S.D. rsd(%) 

Norfab 11HT-26-A1 600 6 7.1 0.29 4.0 6 17.0 2.36 14.0 

750 (Fl) 6** (range 17.1 to 45+) 6 (range 40 to survival) 

Vonar- 3 600 6 11.5 2.04 17.8 6 27.9 10.13 36.2 

750 (Fl) 6 8.9 1.16 13.2 6 18.5 4.59 24.8 

N = Number of rats tested; Mean = mean response time in minutes; 

S.D. = standard deviation; rsd(%) = relative standard deviation in percent, 

i.e., rsd = (S.D./Mean) x 100; F1 = flaming combustion. 

* NR = No response within test period. 

**At 750 OC, in the 12.6-L system, Norfab produced ti's at 17.1, 25.4, 

32.3 and 36.4 min with 2 rats not incapacitated after 45 min; 2 deaths 

at 40 and 120 min were noted and the remaining 4 rats were alive after 

24 h. 

8 
Table 2. Peak Carbon Monoxide Concentrations 

Attained in Chamber Atmospheres 

265-L System (Top Radiant Heating Only) 

Test Material Test Condition 

2.5 W/cm2 5.0 W/cm2 7.5 W/cm2 

Norfab llHT-26-A1 500 ppm at 15 min 4,000 ppm at 8 min 3,500 ppm at 4 min 

Vonar-3 4,600 ppm at 10 min 5,200 ppm at 8 min 6,000 ppm at 6 min 

~_____~~~~~~~~ ~ ~ ~ ~ ~ ~ ~ ~ 

12.6-L System (Combustion Tube Pyrolysis) 

Norfab llHT-26-A1 

Vonar- 3 

Test Condition 

600 OC 750 OC (Flaming) 

4,400 ppm at 5 min 3,000 ppm at 3 min 

5,300 ppm at 5 min 5,300 ppm at 5 min 

9 
Table 3. Hydrogen Cyanide Concentrations 

Attained in Chamber Atmospheres 

265-L System (Top Radiant Heating Only)* 

Test Material Test Condition 

2.5 W/cm2 5.0 W/cm2 7.5 W/cm2 

Norfab llHT-26-A1 Not Detected Detected Detected 

at 4 min at 4 min at 3 min 

Vonar- 3 Not Detected Not Detected Not Detected 

at 7 min at 5 min at 5 min 

~ ~~~~~~~ 

12.6-L System (Combustion Tube Pyrolysis) 

** 

Test Material Test Condition 

600 OC 750 OC (Flaming) 

250 ppm at 4.6 min 70 ppm at 4.6 min 

None Detected None Detected 

Norfab llHT-26-A1 

Vonar-3 

*One sample only was removed by syringe for qualitative analysis; sampling times 

correspond t.0 the times of maximum (visual) smoke concentration in the chamber. 

See text, page 6. 

**HCN analyses for the 12.6-L system were quantitative and the values shown are 

the peak concentrations determined during the tests. Initial samples were taken 

at 1 min and succeeding samples were at 3.6-min intervals. 

10 
2 3 4 56 

1. 

2. 

3. 

4. 

5. 

6. 

7. 

8. 

9. 

10. 

11. 

12. 

13. 

14. 

15. 

16. 

Figure 1. Combustion/Exposure Assembly (265 L) 

Animal exposure chamber 

Gas sampling inlet 

Oxygen inlet 

Thermocouple (air temperature) 

Muffin fan (recirculation assembly), Rotron Mfg. Go., Woodstock, NY 

Chamber connecting tubes 

Mixing/cooling plenum 

Gas deflector 

Heat lamp reflector with two 2000-watt General Electric quartz 

lamps (GE QH2M/T3/CE/HT 240 V) 

Sample combustion chamber 

Sample combustion tray (stainless steel, for 7.6- by 22.9-cm sample) 

Combustion chamber air plenum 

Flexible tube, 10-cm diameter (to recirculate chamber air through 

the sample combustion chamber) 

Muffin fan (for mixing chamber air) 

Cage motor drive shaft and axle support 

Individual rotating cage 

11 
1. 

2. 

3. 

4. 

5. 

6. 

7. 

8. 

9. 

10. 

Figure 2. Combustion/Exposure Assembly (12.6 L) 

Gearmotor, Model 3M126, 6 rpm, 1/20 hp; Dayton Iianufacturing 

Company, Chicago, IL 

Animal Exposure Chamber 

Heating unit, Model NV2X6, 425 watts at 57.5 volts, semicylindrical; 

Watlow Electric Manufacturing Company, 12001 Lackland Road, 

St. Louis, MO 

Same as No. 3 

Thermocouple, chromel-alumel; Omega Engineering Inc., 

Stamford , CT 

Hot wire igniter 

Combustion tube 

Combustion boat 

Spring clamp 

Smoke detector 

12 
REFERENCES 

1. Brown LJ, Johnson RM. Correlation of Laboratory-Scale Fire Test . 

Methods for Seat Blocking Layer Materials with Large-Scale Test Results. 

Report No. DOT/FAA/CT-83/29. Washington, D.C.: U.S. Department of 

Trksportation , Federal Aviation Administration, 1983. - 

2. Crane CR, Sanders DC, Endecott BR, Abott JK. Inhalation Toxicolow: 

111. Evaluation of Thermal Degradation Products from Aircraft and 

Autmbile Engine Oils, Aircraft Hydraulic Fluid, and Mineral Oil. 

Report No. FAA-AM-83-12. Washington, D.C.: Federal Aviation Administration, Office of Aviation Medicine, 1983. 

3. Crane CR, Sanders DC, Endecott BR, Abbott JK, Snith PW. Inhalation 

Toxicology: I. Desiqn of a Stdl-Animal Test System; 11. Determination 

of the Relative Toxic Hazards of 75 Aircraft Cabin Materials. Report 

No. FAA-AM-77-9. Washington, D.C.: Federal Aviation Administration, 

Off ice of Aviation Medicine, 1977. 

4. Federal Aviation Regulations 14 CFR, Part 25.853(~), November 26, 1984. 

5. Hall JR, Stiefel SW. Decision Analysis Model for Passenger-Aircraft 

Fire Safety With Application to Fire-Blockinq Seats. Report No. 

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