A111DS fl fl 4 3 0

NBS

PUBLICATIONS

NBSIR 88-3764

Large-Scale Compartment Fire Toxicity

Study: Comparison With Small-Scale

Toxicity Test Results

Emil Braun, Barbara C. Levin,

Maya Paabo, Joshua L. Gumnan,

Helene M. Clark, Margaret F. Yoklavich

U.S. DEPARTMENT OF COMMERCE

National Bureau of Standards

National Engineering Laboratory

Center for Fire Research

Gaithersburg, MD 20899

July 1988

Supported in part by:

' Consumer Product Safety Commission

30 isda, MD 20207

56

3-3764

p

75 Years Stimulating America's Progress 1913-1988

RESEARCH INFORMATION CENTER

National Institute of

Standards and Technology

Gai thersburg i MD 20899

NBSIR 88-3764

AJ'&se

&CIOD

LARGE-SCALE COMPARTMENT FIRE TOXICITY

STUDY: COMPARISON WITH SMALL-SCALE

TOXICITY TEST RESULTS

Emil Braun, Barbara C. Levin,

Maya Paabo, Joshua L. Gurman,

Helene M. Clark, Margaret F. Yoklavich

U.S. DEPARTMENT OF COMMERCE

National Bureau of Standards

National Engineering Laboratory

Center for Fire Research

Gaithersburg, MD 20899

July 1988

Supported in part by:

U.S. Consumer Product Safety Commission

Bethesda, MD 20207

U.S. DEPARTMENT OF COMMERCE, C. William Verity, Secretary

NATIONAL BUREAU OF STANDARDS, Ernest Ambler, Director
LIST OF TABLES

Page

Table 1. Test Plan for Single Compartment Experiments 43

Table 2. Construction Materials of Large-Scale Single Compartment

Tests 44

Table 3. Location of Instrumentation 45

Table 4. Average Initial and Maximum Mass Loss Rates for FR and NFR

Polyurethane Foam and Cotton Fabric Cushion Assemblies

Exposed to a Smoldering Cigarette 46

Table 5. Extreme Gas Concentrations of CO, C02

, and 02 near the Burn

Room Ceiling During Smoldering Combustion 47

Table 6. Extreme Gas Concentrations of CO, C02

, HCN, and 02 near the

Burn Room Ceiling During Flaming Combustion of Cushion

Assemblies 48

Table 7. Average Mass Burning Rate for FR and NFR Cushion Assemblies

During Smoldering and Flaming Decomposition 49

Table 8. Comparison of the CO, C02

, and HCN Gas Yields for the

Large-Scale Fire Tests . . 50

Table 9. Summary of Results for Burn Room Animal Exposures During

Smoldering Combustion of NFR Foam Cushion Assemblies 51

Table 10. Summary of Results for Burn Room Animal Exposures During

Smoldering Combustion of FR Foam Cushion Assemblies 52

Table 11. Conditions in Animal Exposure Chambers and Animal Responses

During FR and NFR Smoldering Combustion Exposures 53

Table 12. Conditions in Animal Exposure Chambers and Animal Responses

During FR and NFR Flaming Combustion Exposures 54

Table 13. Comparison of C02 /C0 and HCN/CO Yield Ratios for Single

Compartment, and Multi -Compartment Large-Scale Tests with

the NBS Toxicity Protocol for Non-Fire Retardanat, NFR, and

Fire Retardant, FR, Foams 55

Table 14. Comparison of CO, C02 , and HCN Average Yield Values for

Single Compartment , and Multi -Compartment Large-Scale Tests

with the NBS Toxicity Protocol for Non-Fire Retardanat, NFR,

and Fire Retardant, FR, Foams 56

iv
LIST OF TABLES (continued)

Table 15. Comparison of N-Gas Model Calculations with Chemical and

Toxicological Results in Animal ExposureChambers for Single

Compartment Tests and Selected Multi -Compartment and NBS

Toxicity ProtocolTests for Non-Fire Retardant (NFR) Foam

alone and in Combination with Haitian Cotton Cover Fabric..

Table 16. Comparison of N-Gas Model Calculations with Chemical and

Toxicological Results in Animal ExposureChambers for Single

Compartment Tests and Selected Multi -Compartment and NBS

Toxicity ProtocolTests for Fire Retardant (FR) Foam

alone and in Combination with Haitian Cotton Cover Fabric .

Page

57

. 58

v
LIST OF FIGURES

Page

Figure 1. Configuration of Test Room Showing the Sampling Locations

for Burn Room Animal Exposures and Exposure Chamber Animal

Exposures 59

Figure 2. Schematic Floor Plan of Large-Scale Single Room Compartment

Test Facility Showing Instrument Locations 60

Figure 3. Schematic Representation of Burn Room Animal Restrainers

Mounted in Burn Room Wall 61

Figure 4. Mass Loss of NFR Cushion Assemblies During Smoldering

Decomposition 62

Figure 5. Mass Loss of FR Cushion Assemblies During Smoldering

Decomposition 63

Figure 6. Comparison of CO Generation During Smoldering Combustion of

FR and NFR Cushion Assemblies 64

Figure 7. Comparison of C02 Generation During Smoldering Combustion of

FR and NFR Cushion Assemblies 65

Figure 8. Typical Smoke Layer Development for FR and NFR Cushion

Assemblies Undergoing Smoldering Decomposition 66

Figure 9. Comparison of Mass Loss of FR and NFR Cushion Assemblies

During Flaming Combustion 67

Figure 10. Comparison of CO, C02 , 02

, and HCN Concentrations During

Flaming Combustion of FR and NFR Cushion Assemblies 68

Figure 11. Comparison of Smoke Layer Development During Flaming

Combustion of FR and NFR Cushion Assemblies 69

Figure 12. Comparison of Mass Loss for Replicate Tests of FR and NFR

Cushion Assemblies During Smoldering- to-Flaming Transition

Experiments 70

Figure 13. Comparison of CO, C02 , 02

, and HCN Concentrations During

Replicate Tests of NFR Cushion Assemblies 71

Figure 14. Comparison of CO, C02 , 02

, and HCN Concentrations During

Replicate Tests of FR Cushion Assemblies 72

Figure 15. Comparison of Smoke Development During Replicate Tests of

FR and NFR Cushion Assemblies 73

vi
LIST OF FIGURES (continued)

Page

Figure 16. Comparison of the Average Weight Gain for Six Caged Animals

and Two Burn Room Control Animals 74

Figure 17. Comparison of the Integrated Pure CO and CO plus 5% C02 LC50

Values and the Burn Room Integrated CO at Death 75

vii
.

.
LARGE-SCALE COMPARTMENT FIRE TOXICITY STUDY:

COMPARISON WITH SMALL-SCALE TOXICITY TEST RESULTS

Emil Braun, Barbara C. Levin, Maya Paabo,

Joshua L. Gurman, Helene M. Clark, Margaret F. Yoklavich

Abstract

Ten large-scale single compartment fire tests were performed using two

polyurethane foams and a cotton upholstery fabric. Animals were exposed to

the products of decomposition of cushion assemblies burned under three

different combustion modes: 1) smoldering combustion initiated by a cigarette;

2) flaming combustion initiated by a small natural gas diffusion burner; 3)

smoldering- to -flaming transition combustion initiated by a cigarette and

forced into flaming combustion after a prolonged period of smoldering by a small natural gas diffusion burner. Comparison of gas yields (CO, C02

, and

HCN) between these tests and prior large- and small-scale tests showed that the

CO and C02 yields agreed within a factor of 3, while the NBS Toxicity Protocol

produced 10 times more HCN in the flaming mode than the large-scale tests.

Qualitatively, animal deaths were limited to within- exposure plus 24 hrs for

the large-scale animal exposures, while small-scale animal deaths occurred

primarily post-exposure. Within the errors of the NBS Toxicity Protocol ( ± 5-

10 mg/i) , LC50 determinations in the large-scale tests were comparable to the

small-scale tests, except for the small-scale ramped two phase heating and

large-scale smoldering- to - flaming tests. The N-gas model for 30 minute

exposures was expanded to include 4 gases, CO, C02

, HCN and reduced 02

. Model

calculations showed that within- exposure plus 24 hours animal deaths in small

and large-scale tests correlated with model values greater than 0.7. Burn room

animal deaths could not be explained in terms of the four gases used in the Ngas model.

1
Keywords: Cotton; fire tests; large scale fire tests; polyurethane; small

scale fire tests; toxicity; upholstery.

1.0 INTRODUCTION

Few large-scale fire evaluations in which animals have been exposed to the

products of combustion have been reported in the literature. Even fewer

studies have directly compared toxicity data from small- and large-scale

tests. The work to date has previously been reviewed [1]. While the major

effort of these researchers has been based on correlating material loading

concentrations, little attention has been focused on quantifying and

correlating gas yields and the nature of animal deaths between test regimes or developing other alternative correlation models.

The current experiments were intended to futher investigate the relationship

between the small-scale results of the NBS Toxicity Protocol [2] and largescale results. While the initial experiments involved a complex three

compartment configuration with a simulated chair assembly, the present tests

used a simplified single closed compartntent and single cushion assembly. The

basis for comparison between the large- and small-scale tests, however,

remains the same. Comparisons are based on:

• The yields of CO, C02 , and HCN and their relative contributions to

lethality

;

• The nature of those deaths, whether within- or post-exposure;

2
• The similarity of LC 50 values;

and

• The predictability of test animal deaths using the N-gas model.

Comparison will be made between the current test series, referred to as single

compartment test, the prior large-scale tests, referred to as multicompartment tests, and the results from the NBS Toxicity Protocol.

A single closed compartment configuration was selected to reduce the volume of

the test space, as contrasted to previous tests [1], and, thereby, increase the

concentrations of the various products of combustion. Use of a single closed

room also made it possible to express directly the combustion product

concentration in units of mg/f and allowed for a simple comparison to be made

to the bench-scale data. By contrast, the earlier investigation involved a complex flow path and required significant approximations to be made in order

to deduce effective smoke concentrations. The previous effort employed a simulated chair assembly. While this added a touch of realism to the tests,

it increased the tendency of the assembly to ignite spontaneously. To reduce

the likelihood of this occurrence, single cushions were used in the current

s tudy

.

In the large-scale tests, rats were exposed for 30 minutes in a manner similar

to that used in the NBS Toxicity Protocol to the decomposition products from:

• smoldering combustion initiated by a burning cigarette;

• flaming combustion initiated by a small diffusion burner; and

• flaming combustion begun with a cigarette and, after a long

3
smoldering period, forced into flaming combustion with a small

diffusion burner.

During experiments having a smoldering combustion phase (i.e., smoldering only

and smoldering- to- flaming) , test animals were also exposed directly in the burn

room to the products of smoldering combustion. Because of the long term

exposure (greater than 2 hr.), the results of these animal exposures could not

be directly compared to 30 minute animal exposures used in the NBS Toxicity

Protocol. These animal exposures, however, provided an opportunity to evaluate

the effects of transporting decomposition products into the animal exposure

chambers in assessing toxic potency.

Since the test materials used in these experiments had already been

characterized in the small-scale tests in the preceding study, no additional

small-scale tests were run. However, previously unpublished data on the

polyurethane foam materials are presented showing the toxicity of the

combustion products following a two phase decomposition in the NBS Toxicity

Protocol apparatus (i.e., low temperature (300°C) to high temperature (800°C)

pyrolysis) . These results were compared to comparable large-scale tests

( i.e., smoldering- to -flaming transition tests).

2.0 MATERIALS

The materials used in these experiments were the same as used in the previous

study and are described in that report [1]. These materials were two flexible

polyurethane foams and a cotton upholstery fabric. In order to simplify the

experimental design and ensure that the test samples would not undergo

4
spontaneous transition from smoldering to flaming combustion, cushion

assemblies were made by placing two blocks of foam together and completely

covering them with the cotton upholstery fabric. This resulted in a single

square cushion 203 mm thick and 610 mm on a side. Approximately 60-70 % of the

total mass of the cushion assembly was foam.

The two foams used in this study were based on similar formulations. One,

however, contained a chlorinated phosphate fire retardant that allowed it to

meet the State of California's requirements [3] for cigarette ignition

resistance and also for flame resistance of resilient cellular material used in

upholstered furniture. Both the treated (designated FR foam) and the non- treated (designated NFR foam) foam had a density of 22.3 kg/m3

. In the

previous report [1], these foams were labeled foam 32X, for the FR foam, and

foam 32, for the NFR foam.

The upholstery fabric was a Haitian cotton weighing 0.7 kg/m2

. It was selected to ensure that the entire assembly would smolder when exposed to a burning cigarette.

For smoldering experiments, the cushion assemblies were ignited by using

standard cigarettes prescribed by the State of California [3] and the

Upholstered Furniture Action Council [4]

.

They were 85 mm long and had a circumference of 25 mm. The cigarettes were made without filters from natural

tobacco with a density of 0.27 ± 0.02 g/cm3 and a total weight of 1.1 ± 0.1 g. Flaming experiments used a small diffusion burner described later in this

report

.

5
3.0 EXPERIMENTAL DESIGN

A total of ten experiments was conducted to evaluate the toxic potency of the

atmosphere in the test compartment during various phases of fire development.

Upholstered cushions, with an initial mass of approximately 2.5 kg, were

placed on a load platform in a burn room and ignited with a cigarette or a small burner. In each test, rats, exposed to the decomposition products, were

located either in the burn room or in the animal exposure chambers attached to

the burn room. Analytical data on gas temperatures, smoke obscuration, mass

loss, and concentrations of oxygen (02

)

,

carbon monoxide (CO), carbon dioxide

(C02 ), and hydrogen cyanide (HCN) were recorded. These measurements permitted

calculations to be made of the decomposition rate and material mass loading in

the burn room atmosphere based on mass consumed and an estimate of the gas

yields. Material mass loading defines the toxic insult applied to exposed

animals, while gas yields provide an indication of combustion conditions.

Three types of combustion conditions were investigated in this study;

smoldering combustion, flaming combustion, and smoldering- to - flaming

combustion. To initiate smoldering combustion, a smoldering cigarette (as

described in section 2.0) was centered on the top surface of the test cushion.

Flaming combustion was initiated by a small natural gas diffusion burner

equipped with a remotely actuated ignitor producing approximately a 120 mm long

flame from a gas flow of 1.7 i/min (1 kW)

.

The flame was directed at the upper

portion of one side of the test cushion. Smoldering- to - flaming tests employed

a cigarette to initiate smoldering as in the smoldering-only tests. At a

6
predetermined time after the start of smoldering, the burner was ignited and

used to force the transition to flaming combustion.

3.1 Test Plan

Table 1 summarizes the test plan for these experiments showing the number and

placement of animals as well as the decomposition conditions. There were four

smoldering experiments, two for each foam. These experiments represent

replicate tests differing only in the number and placement of animals in the

burn room and animal exposure chambers. In the second of each replicate,

animals were exposed in both the burn room and the animal exposure chambers

.

Two flaming experiments were conducted, one for each foam. No animals were

placed in the burn room for the flaming experiments because of the anticipated

high temperatures. Animal exposures during these tests were limited to three

animal exposure chambers

.

Two replicate tests, under conditions of smoldering- to -flaming combustion, were

also performed for each foam. Animals placed in the burn room were exposed to

the smoldering phase of combustion, while, during flaming combustion, animals

were exposed to the decomposition products in the animal exposure chambers.

During each experiment, the data that were collected continuously on the burn

room environment included temperature, smoke, mass loss, 02

, CO, and C02

. Each

animal chamber was also continously monitored for temperature, 02

, CO, and C02

.

In both the burn room and animal exposure chambers , evacuated bulbs were used

to obtain atmospheric "grab" samples for analysis of HCN.

7
3.2 Room Configuration

The experimental arrangement is shown in figure 1 and consisted of a single

compartment measuring 2.44 m wide by 2.44 m high by 4.57 m long and lined with

non -combustible materials. A doorway measuring 1.02 m wide by 2.03 m high

provided access to the compartment. The compartment was constructed using the

materials listed in table 2 (thermal property data can be found in [1]).

The doorway was closed for all of the tests. For the smoldering- only tests,

the doorway was closed with a sheet of 3.2 mm thick polycarbonate with a 10 mm

undercut. For all other tests, the doorway opening was closed with a sheet of

calcium silicate covering the upper two-thirds of the doorway (i.e., the top

1.35 m of the door opening). The remainder of the door opening was covered

with an aluminum foil covered lightweight wood frame. The aluminum foil

covering provided for pressure relief in the event of a sudden increase in

compartment pressure due to explosive combustion conditions. No such event

ever occurred.

3.3 Instrumentation

Table 3 lists all the instrumentation used in these experiments and the

location of the sampling points. Figure 2 shows the location of the

instruments within the test compartment. Vertical lines of ten thermocouples

each were located in the center of the compartment and in opposite corners.

These were used to determine the upper compartment temperature and the location

8
of the hot upper layer interface during flaming combustion. One vertical and

six horizontal smoke meters were used to determine smoke particulate

stratification within the compartment. Gas probes in the upper (centered, 0.3 m from the ceiling) and lower (room corner, 0.3 m from the floor, 0.6m from

each wall) portions of the compartment continuously monitored the CO, C02 , and

02 concentrations. HCN samples were periodically drawn from the burn room

through the same sampling line that connected the burn room to the animal

exposure chambers. In one test, toluene diisocyanate (TDI) measurements

replaced the HCN samples and were taken from the same location. Since trace

amounts of TDI had been detected in small-scale non-flaming tests, it was of

some interest to see if similar concentrations were detected in the large-scale

tests during smoldering combustion, that is, when HCN generation was very low.

Cushion assemblies were placed on a load cell located near the center and 0.3m

above the burn room floor. The load cell continuously monitored mass loss.

For those animals located in the burn room, additional thermocouples were used

to determine the thermal stress placed on the animals. These thermocouples

were located either within the animal holding tubes (i.e., in contact with the

animals) to monitor an approximation of the animals' body temperature or above

the animals' heads to monitor air temperatures in front of the animals. HCN

samples of the animal exposure chamber atmospheres were only taken while

animals were actually being exposed.

9
3.4 Animal Exposures

Two exposure protocols were used in this series of experiments. In each case,

Fischer 344 male rats weighing 200 to 300 g were exposed in the head- only

mode. One involved a duplication of the exposure conditions previously

employed [1], while the other involved direct animal exposure to burn room

conditions. Because of differences in exposure times, direct quantitative

comparisons could not be made between the two exposure protocols. However,

direct animal exposures were considered important, since qualitative

physiological comparisons were expected to reveal if any significant line

losses of species not monitored occurred during the transfer of combustion

products to the animal exposure chambers . Such an occurrence might account for

the lack of agreement between previous large-scale tests and the NBS Toxicity

Protocol with respect to post-exposure deaths of the animals. All surviving

animals were kept and weighed daily for at least 14 days.

3.4.1 Exposure Chamber Animals

Three NBS toxicity protocol animal exposure chambers (200 S. each) were

connected to the burn* room via a 2.1 m long, 55 mm diameter Pyrex sampling

line located directly above the cushion assembly and 0.3 m from the ceiling.

Each exposure chamber could be isolated from the burn room by its own intake

and exhaust shut-off ports. Throughout an experiment, even when animal

exposure chambers were not being filled, flow of the burn room gases was maintained in a by-pass line, thus providing a means for sampling of the

10
combustion gases for HCN or TDI analysis. An exhaust manifold allowed flow

through the chambers and the by-pass line to be controlled by one blower

motor. The exhaust gases were returned to the inside surface of the south

wall of the burn room at 0.3 m from the ceiling.

For smoldering tests, the animal exposure chambers were opened and connected

to the burn room. Room atmosphere was continuously drawn from the burn room

and passed through each exposure chamber. At predetermined concentrations of

CO, individual chambers were closed and six animals inserted for 30 minutes.

This procedure was followed until all three animal exposure chambers were

closed and animals inserted. In this way, three different smoke concentrations

could be presented to the animals

.

During those tests that involved flaming combustion (i.e., flaming and

smoldering- to -flaming) , animals were only exposed to the decomposition

products from the flaming mode. During these experiments, the animal exposure

chambers were initially disconnected from the burn room, while flow was maintained in the by-pass line. During active flaming, the animal exposure

chambers were opened to the burn room and allowed to fill for predetermined

amounts of time. This resulted in different material loadings each of the

three exposure chambers for use in determining concentration- lethality

relationships for the large-scale flaming tests. Six animals were inserted

into each exposure chamber for 30 minutes

.

11
3.4.2 Burn Room Animals

Smoldering tests afforded the opportunity of inserting animals in the burn

room during the non- flaming thermal decomposition of the cushion assembly

without undue thermal stress. (It was anticipated that upper compartment

temperatures would not, on the average, exceed 40°C.) Two or six animals were

inserted in animal holding tubes mounted on the north wall of the burn room

within 0.3 m of the ceiling. The animal tubes extended 0.3 m into the burn

room (figure 1). Animals were first placed in closed restraining tubes (figure

3), and connected to a respiration monitor via flexible tubing. The

restraining tubes were placed into the animal holding tubes so that the

animals were exposed in a head-only mode. This is similar to the exposure

mode used in the NBS Toxicity Protocol. Because only two transducers were

available for the monitoring of respiration, animals were monitored in groups

of two. For those experiments involving only two animals, continuous

monitoring was possible. When six animals were used, animals were monitored

in groups of two for approximately three minutes per group. For those

smoldering experiments that were forced into flaming combustion, all animals

were removed from the burn room animal holding tubes and the tube ends sealed

before initiation of flaming combustion.

12
4.0

RESULTS

4.1 Material Fire Characteristics

4.1.1 Smoldering Combustion Tests

Cushion assemblies were permitted to smolder in the closed burn room with a relatively quiescent atmosphere. Figures 4 and 5 show the mass loss data for

two replicate tests of the non- fire retarded (NFR) and fire retarded (FR)

polyurethane foam cushion assemblies, respectively, when exposed to a smoldering cigarette ignition source. The data show that the repeatability of

the FR foam assemblies was better than the NFR foam assemblies. While initial

average mass loss rates were the same for repeated tests of similar

assemblies, the average maximum mass loss rates of repeated tests differed for

the NFR assemblies (table 4) . Initial average mass loss rates of 29 mg/s and

36 mg/s were observed for the FR assemblies. This was almost half of the

initial average mass loss rates of the NFR assemblies, 56 mg/s and 53 mg/s.

The average maximum mass loss rate for the second smoldering test (Test 3) of

the NFR assembly was twice as high, 570 mg/s, than a similar assembly tested

in Test 1, 320 mg/s. This difference was probably due to small differences in

the construction of the cushions (i.e., fabric tension, presence of creases,

size of seams, irregularities in the foam, etc.). The FR assemblies had

similar average maximum smoldering rates of 120 mg/s and 130 mg/s, also less

than half of that of the NFR assemblies.

13
Figures 6 and 7 show the CO and C02 gas concentrations in the burn room as a function of time for the four smoldering only tests. As expected from the

mass consumption data, test 3, a NFR cushion assembly, generated higher

concentrations of CO and C02 and earlier than the other tests. Table 5 summarizes the maximum CO and C02 and the minimum 02 concentrations at the time

of maximum CO concentration for each of the smoldering tests. The oxygen

concentration never went below 19%.

The maximum concentration of HCN was determined to be approximately 25 ppm for

Test 3 (NFR foam assembly) based on measurements made in one of the animal

exposure chambers and 6 ppm for Test 4 (FR foam) also based on measurements

made in one animal exposure chamber. The remaining tests showed less than 2 ppm of HCN in the burn room. During Test 3, burn room analysis for HCN was replaced by TDI measurements. Approximately 0.1 ppm of TDI was detected in the

burn room. Since this represented measurements made near the lower detection

limits of the analysis technique and because of the lower anticipated

smoldering rates of the FR assemblies, this analysis was not repeated for the

FR material nor any other large-scale tests.

Figure 8 shows typical smoke filling data for two foam cushion assemblies

undergoing smoldering decomposition (Tests 2 and 3) . Consistent with the mass

loss data, the NFR foam assembly began filling the burn room with detectable

smoke sooner than the FR foam assembly. In tests 2 and 4, FR foam assemblies,

filled the burn room with smoke to the level of the load platform in

approximately 3900 and 3600 seconds, respectively. In the NFR assembly, test 3,

the smoke layer reached the level of the load platform in approximately 2500

14
seconds. Because of a failure in the smoke obscuration meters, comparable data

were not available for test 1.

During these smoldering tests, the average upper compartment temperature never

exceeded 43°C. The maximum recorded temperature was 53°C during the end of

test 3.

4.1.2 Flaming Combustion Tests

Figure 9 shows the mass loss data for these two tests (Tests 5 and 6). Both

tests exhibited a pre-heat period where the mass loss rate was relatively low,

270 mg/s for the NFR foam assembly and 80 mg/s for the FR foam assembly. Once

active burning was established on the cushion assemblies, the average maximum

mass loss rate was approximately 1900 mg/s for both foam cushion assemblies.

Based on initial and final masses, approximately 90% of the NFR foam assembly

was consumed during the flaming tests, while approximately 60% of the FR foam

assembly was consumed. During the peak burning period, the upper layer gas

temperature was approximately 120° C for both tests.

Figure 10 shows the comparison of CO, C02

, 02, and HCN development in the burn

room during these flaming tests. Consistent with the mass loss data, the gas

data show that the NFR foam assembly generated higher concentrations of CO and

C02 than the FR foam assembly. HCN measurements during these tests showed that

the maximum measured HCN concentration in the burn room was higher for the FR

assembly, approximately 170 ppm, than for the NFR assembly, approximately 100

ppm. Also, based on the fact that nearly 1/3 more NFR assembly was consumed

15
than FR assembly, it was not surprising to find that the oxygen concentration

was lower for the NFR assembly than the FR assembly. These results are summarized in Table 6. Differences in the time to peak CO and C02 are indicative of non- flaming decomposition occurring in the cushion residue during

the post- flaming period. Differences in peak times between C02 and HCN can be

attributed to the HCN sampling interval and not necessarily to differences in

HCN generation rates

.

The development of the smoke layer in tests 5 and 6 can be seen in figure 11.

The time for the development of a smoke layer to 2.0 m, 0.3 m and floor level

are tabulated below. These times reflect differences in both ignition delay,

as

Time for the Smoke Laver to Reach Various Levels

Time (s)

Material Test # 2.0 m 0.3 m Floor

NFR 5 240 600 1020

FR 6 300 1020 1320

represented by the time to 2.0 m, and in rate of fire growth, as seen in the

time from 2.0 m to 0.3 m and from 0.3 m to the floor.

4.1.3 Smoldering- to-Flaming Combustion Tests

The mass burning rate curves for both the NFR and FR foam cushion assemblies

appear to exhibit three distinct burning phases (figure 12) . The mass burning

rate for each phase is summarized in table 7. The first two phases correspond

to smoldering decomposition. As noted previously, the initial mass burning

16
rate may be predominantly controlled by the decomposition of the cover fabric,

while the second and larger mass burning rate can be attributed to in-depth

smoldering of the foam cushion. While the former is a surface expansion of

the smoldering front, the later is a volumetric ( three-dimensional) expansion

of the smoldering front. These values are comparable to those from the

smoldering- only tests (section 4.1.1). Also, during flaming combustion, the

mass burning rate for these tests was comparable to the flaming- only

decomposition data (section 4.1.2) for the NFR foam cushion assembly, but about

70% to 90% greater than the previous FR foam cushion assembly tests. At the

time of the transition to flaming combustion approximately 51% and 35% of the

NFR and 17% and 23% of the FR cushion assemblies were consumed.

Figure 13 shows the comparison of CO, C02

, HCN, and 02 between replicate tests

of the NFR cushion assembly. The same data are presented in figure 14 for

replicate tests of the FR cushion assembly. The gas generation data were

consistent with the mass loss data. Ignoring the time delay to initiate

flaming combustion, which was controlled by the death and removal of the burn

room animals, the NFR cushion assemblies appear to have more reproducible

maximum CO, C02 and HCN and minimum 02 concentrations than the FR cushion

assemblies. The decrease in the concentration of gases beyond the time of the

maximum values was due to the leakage of outside air into the burn room caused

by the cooling of the burn room atmosphere.

Maximum CO . C0o , HCN. and Minimum 0„ Concentrations

NFR FR

Test 7 Test 9 Test 8 Test 10

CO , ppm 9800 10500 9500 5900

co2 ,% 5.2 4.9 7.3 5.4

HCN, ppm 140 90 450 370

o2 ,% 13.6 13.9 11.2 13.6

17
However, the FR cushion assemblies differed in initial weight by 0.22 kg (2.62

kg and 2.40 kg), while the NFR cushion assemblies differed by only 0.12 kg

(2.62 kg and 2.50 kg). At the conclusion of the tests, nearly 100% of the NFR

cushion assemblies and 75% of the FR cushion assemblies were consumed.

Figure 15 shows a comparison of the development of the smoke layer during

these four tests. Because of the higher mass loss rates during smoldering

combustion of the NFR cushion assemblies, the smoke layer reached the floor of

the burn room sooner than for the FR cushion assemblies. Both cushion

assembly types filled the burn room with smoke before the initiation of

flaming combustion.

Time for the Smoke Laver to Reach Various Levels

Material Test # 2.0 m Time (s)0.3 m Floor

NFR 7 200 2920 3270

NFR 9 500 2900 4365

FR 8 800 4000 5700

FR 10 1100 3900 6600

Gas yields for all ten tests were calculated for CO, C02

, and HCN. A

tabulation of these results, table 8, show that CO and C02 yields were

generally constant for a given decomposition mode. During smoldering

combustion, the average CO yields were 0.09 kg/kg for NFR foam assemblies and

0.11 kg/kg for FR foam assemblies. At the same time, C02 yields were 0.4

18
kg/kg and 0.6 kg/kg for the NFR and FR foam assemblies, respectively. During

smoldering combustion, HCN was not detected or detected only at very low

concentrations. Therefore, no determination was made of HCN yields. For

flaming combustion, the CO yields, 0.11 kg/kg for NFR and 0.12 kg/kg for FR

foam assemblies, were comparable to the smoldering combustion data, while the

C02 yields, 2.2 kg/kg for NFR and 1.9 kg/kg for FR foam assemblies, were 3 to

5 times greater than during smoldering combustion. While significant amounts

of HCN were produced during direct flaming combustion, 2 x 10“ 3 kg/kg for NFR

foam and 4 x 10“ 3 kg/kg for FR foam, lh times as much HCN was produced by

smoldering NFR foam prior to flaming combustion, 3 x 10“ 3 kg/kg and 3 x 10“ 3

kg/kg, and 2h times more for FR foam, 1 x 10“ 2 kg/kg and 1 x 10“ 2 kg/kg.

4.2 Animal Exposures During Smoldering Combustion

During the smoldering combustion phase of eight tests, long term animal

exposures to the decomposition products in the burn room were conducted. In

addition, 30 minute animal exposures were performed during two of the

smoldering- only tests using three animal exposure chambers connected to the

burn room. The purpose of the long term within- room exposures was to

determine the extent to which transporting decomposition products to the animal

exposure chambers would affect observed lethalities and the time of occurrence

of death. The exposure chamber animal response data were used to make

comparisons with small-scale test results.

19
4.2.1 Burn Room Animals

Since burn room animal exposures represented a new protocol, there was some

concern that restraining the animals in closed holders and inserting them into

extended exposure tubes would place undue stress on them, resulting in the

restraining system itself causing injury or death. In order to determine the

impact of the restraining system on animal survivability, a control test was conducted. Two animals were selected for long term exposure to test

conditions without the presence of combustion products. The animals were

placed in animal holders and inserted into the animal exposure tubes in a head- only mode. The animals were connected to the respiration monitor, and

the temperatures within the restrainers as well as the atmospheric temperature

at their noses was recorded for three hours. After this control run, the

animals were returned to holding cages and observed for 14 days.

The ambient temperature to which the animals were exposed was 24° C. The

temperature inside the animal holding tubes reached an average of 35 °C with a maximum of 37° C. Figure 16 shows the growth data for the two control test

animals and the average for a set of six control animals who were just kept in

their cages. Prior to the exposure all of the animals exhibited approximately

the same weight gain. Immediately after the exposure (i.e., within 24 hrs)

,

the two test animals showed slight drops in weight, 7 g and 12 g, compared to

the non- exposed control animals. However, normal growth rates were re- established within 48 hrs after the termination of the blank exposure. This

20
has been shown [5] to be the normal animal response to the tubing or restraining process.

Table 9 summarizes the results of burn room animal exposures for the NFR foam

cushion assemblies. Tests 1 and 9 involved the use of 6 animals per test;

however, for test 1, individual animals were progressively removed from the

burn room at increasing test times, for test 9, all animals were removed from

the burn room at the same time. The removal times for test 1 were based on

the CO concentration, while, for test 9, the removal time was based on the

initial detection of arrested respiration (this would be indicative of death)

of any of the animals. Tests 3 and 7 used only two animals per test. The

exposures were allowed to progress to the death of both animals. While the

time integrated average values for material loading based on mass consumed, CO,

and C02 were low, the exposure time was long. The shortest exposure time was

4380 s and the longest was 8200 s. During the early development of smoldering

in the cushion assembly, the concentrations of the lethal gases were near

ambient conditions. With two exceptions, the onset of death based on the

integrated CO value varied from 52,000 ppm-min to 83,000 ppm-min. One animal

died after only a 23,000 ppm-min integrated CO exposure and one died after

109,000 ppm-min. Endpoint (death or removal of animals) concentrations of CO,

C02 and 02

, appear not to be lethal at exposures up to one hour [6].

Since the burn room animals were exposed to a changing combustion atmosphere,

an average material loading was computed. This was estimated by averaging the

time dependent material loading from the start of the test until the

termination of the exposure. The material loading at a specific time, t

i

, was

21
determined by computing the ratio of the cushion assembly mass loss until t

i , as measured by the load cell, and the upper layer volume at t i , as measured by

the smoke meters. The material loading calculations did not take into account

any losses of smoke from the burn room or entrainment of air into the burn

room. However, the horizontal smoke meters were used to correct for combustion

product stratification in the burn room. Therefore, the average material

loading was an estimate of the concentration of material consumed at the level

of the burn room animals. The average material loading was found to vary from

3 mg/i to 15 mg/£.

Table 10 presents analogous results for the FR foam cushion assembly. With

two exceptions, the onset of death based on the integrated CO concentration

occurred between 67,000 ppm-min and 99,000 ppra-min. One animal died at an

integrated CO concentration of 17,000 ppm-min. At the highest value of

143,000 ppm-min, 3 out of 6 animals survived the 14 day post-exposure

observation period. Average material loading varied from 1 mg/SL to 6 mg/i

.

Endpoint concentrations for CO, C02 , and 02 were low (i.e., when animals were

removed from the burn room) and the cause of death does not appear to be caused

by the presence of these gases alone.

4.2.2 Exposure Chamber Animals

Two tests involved the exposure of animals in the animal exposure chambers to

steady- state concentrations of decomposition products from the smoldering

phase of burning (Tests 3 and 4) . Following a previously established protocol

[1]

,

three groups of six animals were exposed to increasing concentrations of

22
decomposition products transported from the burn room to three animal exposure

chambers . The animal exposure chambers were filled for varying times to allow

for a variation in gas concentrations between each chamber. After the

chambers were sealed from the burn room, animals were inserted into the

chambers for 30 minute exposures. The calculated material loading and the

average CO, C02

, 02 , and HCN concentrations in each exposure chamber are listed in table 11 along with the animal response data. For the NFR foam

cushion assembly, animal deaths were observed at exposure chamber material

concentrations of 30 mg/i and 32 mg/i , based on mass consumed. The single

animal death at 30 mg/f was found during the second 24 hr period after the

termination of the exposure. No post-exposure deaths were observed beyond this

time in any other tests. At 32 mg/i , one animal died during the exposure and

one died within 24 hrs of the exposure. The maximum loading for the FR foam

cushion assembly was 24 mg/i. No animal deaths were recorded within- or postexposure from the FR assemblies. However, the concentrations of gases were

much lower than for the NFR assemblies.

4.3 Animal Exposures During Flaming Combustion

Six tests were conducted in which the animals were exposed to the products

from the flaming phase of combustion. Two tests (5 and 6) , one FR and one NFR,

were initiated by a small diffusion burner causing the cushion assemblies to

ignite into flaming combustion. The remaining four tests, two FR (7 and 9) and

two NFR (8 and 10) , were initiated by a smoldering cigarette and later forced

into flaming combustion by a small diffusion burner. Only animals in the

23
animal exposure chambers were exposed to the products of flaming decomposition.

Table 12 summarizes the results of the animal exposures during these tests.

During the flaming initiated tests, tests 5 and 6, the lowest material

loadings, at which deaths were observed to occur, were 25 mg/i and 33 mg/i for

the FR and NFR foam cushion assemblies, respectively. All but one animal

death occurred during the exposure period. With the exception of test 7 at 44

mg/i loading in which one animal died within 24 hours of the test, all of the

animals exposed to the decomposition products from the smoldering- to - flaming

transition experiments died during the exposure. The data show that it was difficult to obtain conditions that resulted in partial deaths among the

eighteen animals exposed in the animal exposure chambers per test. With the

majority of the data showing 0 out of 6 deaths or 6 out of 6 deaths, the

concentration-response curve for these materials must be very steep. The

effects of gases, individually and in combination will be discussed in section

5.4.

5.0 DISCUSSION

5.1 Gas Yields

Since gas yields are determined by two measured variables, each with an

independent measurement error, the yield calculations have a combined error

approximating the sum of the individual instrument errors. The primary cause

of uncertainty in the yield calculations during smoldering combustion is the

24
small sample weight loss. For flaming combustion, the greatest uncertainty is

in the determination of the smoke volume. Differences in yields of less than a factor of 3 and in yield ratios of less than a factor of 10 may not be

meaningful. A comparison of the yield ratios for C02 /C0 and HCN/CO are listed

in table 13 for the three testing environments. With the exception of the

C02 /C0 and HCN/CO ratio for NFR foam and the HCN/CO for FR both during flaming

combustion, the yield ratios differ by less than a factor of 3. The C02 /C0

yield ratio varied from 15 to 40 for FR foam and 20 to 80 for NFR foam

assemblies during flaming combustion and 5 to 8 for non- flaming or smoldering

combustion. During flaming combustion, the HCN/CO yield ratio varied from 0.01

to 0.11 for both foam assemblies. While little or no HCN was detected in the

current single compartment experiments during smoldering combustion and,

therefore, no determination was made of HCN yield, previous experiments [1]

showed that the HCN/CO was very small for smoldering combustion, less than

0.001 to approximately 0.01. For flaming combustion, the NBS Toxicity Protocol

had the highest HCN/CO ratio.

While gas yield ratios minimize random errors from sample weight or smoke

volume measurements, systematic errors in gas yield measurements from either

the small- or large-scale tests could result in comparable gas yield ratios.

Thus it is also necessary to examine the yield values themselves. Analysis of

the actual yield data, table 14, shows that the production of HCN, on a unit

mass basis, exhibited a similar trend between the three testing environments.

While very little HCN (less than 0.1 x 10” 3 kg/kg for NFR assemblies, and only

0.4 x 10” 3 kg/kg for FR assemblies) was produced in any of the smoldering tests

for both materials or non-flaming decomposition tests in the NBS Toxicity

25
Protocol, flaming combustion in each test environment produced comparable large

increases in HCN yields. For each material, the greatest HCN concentration

occurred during the smoldering- to- flaming tests. For the NFR foam, the

smoldering- to -flaming tests produced 2 to 18 times more HCN than the flamingonly tests. Three to 9 times more HCN was produced for FR foam during

smoldering- to -flaming transition experiments than during flaming-only tests.

It should also be noted that, since the HCN concentrations were not

continuously determined, the values presented may not represent peak

concentrations

.

In general, the decomposition environments developed in the three test

conditions for the three combustion regimes were performed under comparable

ventilation conditions as defined by the C02 /C0 ratio. In those cases where

HCN was measured at both scales, the NBS Toxicity Protocol results were similar

for HCN production to the large-scale single room tests in 3 out of 4 cases

(table 14) . The HCN yields from the multi-room tests were consistently an

order of magnitude lower than from the single room tests. No simple explanation

is available for this difference in HCN behavior between single and multi -room geometries. HCN production was greatest for smoldering- to -flaming combustion

and lowest for smoldering or non- flaming combustion. Flaming combustion

produced an intermediate amount of HCN.

5.2 Time of Mortality

The NBS Toxicity Protocol data and large-scale multi -compartment data[l] taken

from the previous study are, for convenience, shown on tables 15 and 16 along

26
with the data from the present study. The results of the NBS Toxicity Protocol

show that for FR and NFR foams in the non- flaming exposures caused almost

exclusively post-exposure deaths. Deaths, for the non-fire retardant foam,

occurred as late as 28 days post -exposure and, for the fire retardant foam, as late as 10 days post- exposure . The cotton fabric produced deaths 4 days postexposure .

During the multi -compartment large-scale smoldering exposures, no deaths were

observed for FR and NFR foam cushion assemblies within- or post- exposure in the

animal exposure chambers. During the current series of experiments, tests were

designed to increase the likelihood of animal deaths by increasing gas

concentrations in the animal exposure chambers. In this way, a better

determination might be made of the differences in within- and post-exposure

deaths between large- and small-scale tests.

In the smoldering mode, for the NFR foam cushion assembly, two within- exposure

deaths were observed (table 15). In one case, there was a post-exposure death

within 24 hours of the termination of the exposure. Fifteen animals survived

the initial exposure plus 24 hours. No additional deaths resulted during the

post-exposure observation period. The CO concentrations for single compartment

tests were comparable to or greater than those reported for the small-scale

tests and the C02 and 02 concentrations were very similar. For the FR foam

cushion assembly (table 16) decomposed in the smoldering mode, no deaths were

observed at CO concentrations two times greater than the small-scale FR foam

tests and comparable to the small-scale cotton fabric tests.

27
In 1982, Birky [7] reported on preliminary results of comparisons between the

smoldering combustion of flexible polyurethane foam slabs in large-scale single

closed compartment tests and in the NBS Toxicity Protocol. He similiarly

observed that, while post- exposure animal deaths were common for flexible

polyurethane foam under non- flaming conditions in the NBS Toxicity Protocol, no post-exposure animal deaths occurred following a comparable 30 minute exposure

to the decomposition products from smoldering the same foam in a large-scale

compartment

.

Flaming-only animal exposure tests were not performed during the multicompartment large-scale tests. However, single compartment flaming tests data

are available for comparison to small-scale flaming tests. Small-scale

flaming tests produced some within-exposure deaths, but also showed a large

fraction of post- exposure deaths for the FR foam. Under flaming conditions no deaths were observed for the NFR foam or cotton fabric in the small-scale tests

at the highest material concentration. The NFR foam cushion assembly under

direct flaming conditions produced 11 out of 18 animal deaths in the single

compartment test. The FR foam cushion assembly had 9 out of 18 animal deaths.

All of these deaths occurred within the 30 minute exposure period. The FR foam

tested in the small-scale test had both within- and post-exposure deaths.

Smoldering- to- flaming transition tests were carried out to assess the increase

in toxicity of pre- smoldering the foam cushion assemblies. Small-scale

toxicity assessment of this combustion condition was recently conducted [8]

for the NFR foam. In these small-scale tests, out of eighteen animals tested,

28
9 died within the 30 minute exposure and 5 died post- exposure . The last death

was 14 days from the termination of the exposure. The multi -compartment tests

showed that, at high concentrations, the resulting decomposition products were

lethal within exposure for both the NFR and FR foam cushion assemblies,

generally, killing all of the test animals. However, one post-exposure death

was observed in the multi -compartment chair assembly tests as well as one post-exposure death during single compartment cushion assembly tests. Both

post-exposure deaths were observed for the NFR foam assembly (i.e., within the

first 24 hrs) . While the single compartment tests were conducted at lower

material concentrations than the multi -compartment tests, the results were not

substantially different. In general, animal deaths occurred within exposure

and, as just noted, no surviving animals died after the first 24 hrs postexposure .

While every testing regime can develop combustion product concentrations

resulting in the death of exposed animals, qualitative differences exist in the

time of death between the large- and small-scale tests. Post-exposure (beyond

24 hrs) animal deaths are more likely in the NBS Toxicity Protocol than in the

large-scale tests.

5.3 Mortality

The lack of post- exposure animal deaths in the earlier multi -compartment

experiments prompted the decision to place animals into the burn room in a

head- only exposure during smoldering combustion. The exposure times were

greater than the 30 minutes used in the NBS Toxicity Protocol. Direct

29
comparisons between animal responses in the large-scale tests and the NBS

Toxicity Protocol could therefore not be made. Levin et al [9] have used rats

similiar to those used in this investigation to study the relationship between

exposure time and gas concentration for three simple gas mixtures - CO alone,

CO with 5% C02

, and CO plus 1/2 the LC 50 concentration of HCN. Their study

involved exposure times extending from 360 seconds to 3600 seconds. Their data

can be summarized for each gas mixture by computing the time integrated CO

concentration, CT, over the entire test period such that

n

CT = 2 [CO] •<ti -ti _ 1

) , (1)

i=l

where

[CO] = CO concentration (ppm) at time t i and

t i = the i th time interval (minutes)

.

Linear regression fits of their data are shown in figure 17. For illustrative

purposes only, their data have been extrapolated to 9000 seconds - dotted lines

in figure 17.

Equation (1) was applied to the burn room CO data for those tests involving

smoldering combustion and burn room animal exposures. The CT values for CO at

the time of burn room animal removal or death were computed. Burn room animal

deaths occurred between 4290 seconds and 9000 seconds. These values are shown

in figure 17 as individual data points for both NFR and FR assemblies.

If CO intoxication was the primary cause of death, the computed burn room CT

values at death would be expected to be close to the CO line shown in figure

17. It can be seen that the large-scale CT data lie well below the

30
extrapolated pure gas data. This indicates that other atmospheric agents were

present during these tests to increase the toxic potency of the decomposition

products beyond that accounted for by CO and CO in combination with C02

. As

previously noted, since little HCN is produced during smoldering combustion,

attempts were made to detect the presence of TDI , with negative results.

Three possibilities exist to account for this level of toxicity: the existence

of other direct toxicants; the existence of indirectly acting toxicants (i.e.,

a decomposition component that the body can metabolize to form a toxic

product) ; or the effects of smoke particulates on the respiratory system. A

more detailed analysis of the possible decomposition products may reveal other

possible agents, directly or indirectly acting. However, additional thought

must be directed to the effect of small- and large-scale tests on soot

particulates which could affect the inhalation toxicity of the decomposition

products

.

5.4 LC 50

The LC 50 values in the NBS Toxicity Protocol, based on mass consumed, for the

two foams and cotton fabric were previously found to be:

31
Combustion Mode Material LC 50 (30 min + 14 days)

(mg/l)

Non- Flaming NFR 33

FR 23

Cotton 25

Flaming NFR >40

FR 26

Cotton >50

Ramped NFR 22

During the multi -compartment tests, no LC 50 value could be determined for

either NFR or FR chair assemblies undergoing smoldering combustion. While no

LC 50 could be determined for the smoldering- to - flaming tests of the FR chair

assembly, the LC 50 value for this test was less than 64 mg/i . For the NFR

chair assembly smoldering- to-flaming tests the LC 50 was estimated to be between

44 mg/i and 55 mg/i

.

For the single compartment large-scale tests, estimated LC 50 values were:

Combustion Mode Material LC50 (30 min + 14 days)

(mg/1)

Smoldering NFR- cushion 34

FR- cushion >24

Flaming NFR- cushion 32

FR- cushion 20-28

Smoldering- NFR- cushion 46

Flaming FR- cushion 26

32
An uncertainty of 15-40% has generally been associated with the NBS Toxicity

Protocol determination of LC50 . This represents a 5 to 10 mg/i variation about

the reported LC50 value. These include the variabilities in the measurement

process and animal responses. The large-scale tests can not be expected to

have an error range better than the NBS Toxicity Protocol. Therefore,

differences of less than about 40% are unimportant. Applying the lower error

range to the results of both tests shows that for smoldering/non- flaming and

flaming conditions the LC50 of the foam cushion assembly has an equivalent

toxicity to the polyurethane foams in the NBS Toxicity Protocol. The

smoldering- to -flaming large-scale experiments had an LC50 for NFR of 46 mg/i

and for FR of 26 mg/i. Ramped two phase heating tests of the FR foam were not

performed in the NBS Toxicity Protocol. The ramped two phase heating of NFR

foam had an LC50 of 22 mg/i . While these results differ by more than the upper

error bound, it should be noted that the ramped two phase heating tests in the

NBS Toxicity Protocol do not represent flaming combustion of the substrate

residue and are, therefore, not comparable to the smoldering- to -flaming largescale tests.

5.5 The N-Gas Model

Recently, the National Bureau of Standards has developed the N-Gas Model [9,10]

which approximates the toxicity of combustion atmospheres based on the primary

toxic gases generated during the flaming and thermal decomposition of

materials. During the earlier multi-compartment experiments, the model used

was based on the interaction of 3 gases, CO, C02

, and HCN. It was empirically

33
determined that combining 30 minute within-exposure deaths with 24 hour postexposure deaths resulted in a model that related the three gas interaction by:

m[C0] [HCN]

[C02 ]-b LC 50 (HCN)

( 2 )

where m and b were the slope and y- intercept of the no death line of CO in the

presence of C02 and [CO], [C02 ], and [HCN] are average atmospheric exposure

concentrations during a 30 minute exposure period. Values for m and b have

been recomputed to represent the LC 50 line of CO in the presence of C02 and

were found to be -18 and 121788, respectively. The LC 50 (HCN) is 160 ppm, the

lethal concentration of HCN that will kill 50% of the exposed animals in 30

minutes. Values below 1 indicate that no animals are expected to die, while a value of 1 or more indicates that animals would be expected to die from the

exposure. Equation (1) has now been expanded to include the effects of

reduced oxygen [8] by an additional term:

m[C0]

[co

2

]-b

[HCN]

lc

5Q (hcn) + 21^10 j

21-LC^

q

(0

2

) > 1 , (3)

where LC 50 (O2 ), the lethal concentration that will kill 50% of the animals, is

5.4%.

Tables 15 and 16 apply equation (3), the 4-gas model, to the data from the

current set of experiments as well as to the multi -compartment experiments of

foam cotton assemblies and to the NBS Toxicity Protocol tests on the individual

components. The data are organized according to increasing N-gas model

predictions within a test series. As was noted in the previous work [1], the

34
N-gas model, with N=3 , did correctly predict animal survivability. In the

current experiments, the N-gas model, with N=4, shows that for the single

compartment tests there was sufficient CO, C02

, HCN, and reduced 02 to account

for the observed deaths for both the FR and NFR foam cushion assemblies under

all modes of decomposition. With the exception of one NFR exposure chamber

containing combustion products resulting from smoldering- to -flaming combustion

(i.e., 1.26), the largest 4-gas value associated with no animal deaths was

0.75. The FR foam cushion assembly tests exhibited a similar exception (i.e,

1.01), and the largest 4-gas value associated with no animal deaths was 0.95.

Applying the 4- gas model to the NBS Toxicity Protocol results showed that the

model correctly predicted no within- plus 24 hour post-exposure animal deaths,

but underestimated the observed toxicity for the non-flaming and flaming tests

by not including post-exposure deaths. For the ramped two phase non-flaming

experiments, the N-gas model produced values between 0.95 and 1.58. This

correctly predicts the within- exposure animal deaths. Again, post-exposure

animal deaths were observed and not predicted by the model.

The 4-gas model correctly predicts within- plus 24 hour post-exposure animal

deaths for model calculations resulting in values of 0.8 and greater for NFR

foam and of 0.7 and greater for FR foam in the large-scale tests and in the

NBS Toxicity Protocol.

6.0 SUMMARY

The large-scale experiments performed in this report represent a simplified

geometric configuration extending the techniques of previous experiments

35
conducted with the same materials. Using the same criteria developed for

comparison of large-scale multi-compartment tests and the NBS Toxicity

Protocol, the data from these experiments were compared to the previous

results. The basis for a detailed comparison was determined by:

• The nature (yield) of the decomposition products and their

contribution to the relative toxicity of the combustion

atmospheres

;

• The occurrence of death, whether within- or post - exposure

;

• The similarity of LC 50 values;

and

• The predictability of the N-gas model with N=4 (C02

, CO, HCN and

02 ).

In addition, long term (1 to 2h hr from the start of the experiment) burn room

exposures were conducted to determine the possible impact of line losses on

the observed toxicity of exposure chamber animals. The basis for evaluation

was a comparison of animal responses during long term (up to 1 hr) pure gas

(CO, C02 and HCN) exposures.

A comparison of gaseous yields between the large- and small-scale tests showed

that, for both the FR and the NFR foams, the CO and C02 yields did not vary by

more than a factor of 3, except for the NFR flaming CO yield following

prolonged smoldering combustion, which showed a factor of 4 difference between

the two large-scale tests. These differences, however, may not be significant

because of multiple measurement errors.

36
Under flaming-only combustion conditions, the HCN yields for both FR and NFR

were about the same for the small-scale and single compartment large-scale

tests. The multi -compartment large-scale tests were an order of magnitude

lower. During the flaming phase of the smoldering- to -flaming experiments, the

HCN yield was greatest for the NBS Toxicity Protocol followed by the single

compartment tests and the multi -compartment tests. Differences between the

three tests varied by an order of magnitude for the NFR foam. For the FR

foam, the NBS Toxicity Protocol and the single compartment tests were

comparable, while the multi -compartment tests differed by less than a factor of

three

.

Comparing the yield ratios of C02 /C0 and HCN/CO for all three test conditions

showed that good agreement was obtained for the FR foam with the exception of

HCN/CO yield ratio during flaming combustion in the NBS Toxicity Protocol.

Good agreement was also observed for 5 of the 8 groups of measurements for the

NFR foam. The exceptions were flaming combustion C02 /C0 yield ratios for the

multi -compartment and NBS Toxicity Protocol and for the HCN/CO yield ratio for

the NBS Toxicity Protocol.

As observed in the previous large-scale multi -compartment tests, no postexposure animal deaths were observed beyond the first 24 hours in the largescale single compartment tests. This is in sharp contrast to the large number

of post-exposure deaths beyond the first 24 hours observed in the NBS Toxicity

Protocol. The N-gas model did not predict these deaths, since it was developed to predict within- exposure plus 24 hour deaths. A qualitative

37
difference (the time at which animal deaths are observed) remains unexplained

between large-scale tests and the NBS Toxicity Protocol.

Under those conditions where an LC 50 value could be computed, the single

compartment results were in reasonable agreement with the NBS Toxicity

Protocol, assuming that the large-scale single compartment tests had a range

of uncertainty comparable to the NBS Toxicity Protocol.

With several exceptions, the N-gas model (with N=4) provided a reasonable

assessment of within- exposure deaths of all three test conditions. Only twice

out of 24 exposures during the single compartment experiments did the N-gas

model predict within- exposure animals deaths and none were observed.

Long term burn room animal exposures during smoldering decomposition showed

that toxic atmospheres could be developed. Although lethal concentrations of

CO and C02 were insufficient to account for the observed within- exposure

deaths (which is consistent with the NBS Toxicity Protocol results) , no postexposure deaths beyond the first 24 hours were recorded. No animal deaths were

observed during smoldering decomposition of FR foam assembly. This was due to

the apparent extinguishment of the assembly and not to the inherent reduced

toxicity of its decomposition products.

38
7.0 CONCLUSIONS

Ten large-scale single compartment fire tests were performed using two

polyurethane foams and a cotton upholstery fabric. The toxicological and

combustion results of these tests were compared to previous small- and largescale tests on the same materials. It was found that:

• Within an order-of -magnitude both the large-scale tests and the NBS

Toxicity Protocol yield similar LC 50 results. However, the

qualitative differences in time of animal deaths between small- and

large-scale tests indicate that significant differences exist.

• Based on HCN production, the decomposition mechanisms in the largeand small-scale tests are not the same.

• The N-gas model for 4 gases, CO, C02

, HCN and reduced 02, was able

to account for animal deaths within- exposure plus 24 hours during

the large-scale tests and the lack of within- exposure plus 24 hours

animal deaths during the small-scale tests.

• Burn room animal deaths, associated with smoldering fires, could

not be accounted for by the concentrations of the four gases used

in the N-gas model.

39
8.0 RECOMMENDATIONS

While the N-gas model has proven to be a useful predictive tool for withinexposure plus 24 hour deaths in both large- and small-scale tests, the current

lack of correlation with regard to post-exposure deaths beyond 24 hours

suggests further avenues of research. These are:

1.

Because of the varying relative importance of HCN and the currently

unknown toxicants, true smoldering combustion should be studied in

the NBS Toxicity Protocol. This can be accomplished with the

cotton fabric and foam assemblies studied in this report.

2. The search for the unknown toxicant(s) produced during smoldering

and non- flaming combustion of flexible polyurethane foam should

continue and be expanded to include a study of the effects of

particulates on the observed toxicity of smoke from polyurethane

foam and cotton fabric. Particulate characterization for

smoldering and non- flaming modes of decomposition should be

conducted and correlated to the observed animal responses.

3. While a relationship has been developed between the large-scale

tests and the NBS Toxicity Protocol, this has been limited to a detailed study of polyurethane foam and cotton fabric combustion.

More materials need to be investigated in large- and small-scale

studies to determine the universality of the existing work.

40
9.0 ACKNOWLEDGMENTS

The authors gratefully acknowledge the assistance of Sam Steel, Richard Zile,

Mel Womble, Roy McLane , Gary Roadarmel, and John Shields in conducting the

large-scale tests and Carmen Davis for her care and feeding of the test

animals. These tests were performed under a tight schedule made possible by

their dedication and thoughtfulness. We would like to also thank the Consumer

Product Safety Commission, and especially the project officer, Jane McCaulley,

for supporting in part this experimental program.

41
10.0 REFERENCES

1. Braun, E., Levin, B. C., Paabo, M. , Gurman, J., Holt, T. , Steel, J. S.,

Fire Toxicity Scaling, NBSIR 87-3510, U. S. Dept. Commerce, Nat'l. Bur.

Stand. (1987)

.

2. Levin, B. C., Fowell, A. J., Birky, M. M. , Paabo, M. , Stolte, A., and

Malek, D., Further Developemnt of a Test Method for the Assessment of

the Acute Inhalation Toxicit of Combustion Products, NBSIR 82-2532, U.

S. Dept. Commerce, Nat'l. Bur. Stand. (1982).

3. Flammability Information Package, State of California, Department of

Consumer Affairs, Bureau of Home Furnishings, North Highlands, CA

(1985).

4. Important Consumer Information from UFAC, Upholstered Furniture Action

Council, High Point, NC (1984).

5. Levin, B. C., Paabo, M. , Fultz, M. L. , Bailey, C., Yin, W. , and Harris,

S. E., An Acute Inhalation Toxicological Evaluation of Combustion

Products from Fire Retarded and Non- Fire Retarded Flexible Polyurethane

Foam and Polyester, NBSIR 83-2791, U. S. Dept. Commerce, Nat'l. Bur.

Stand. (1983)

.

6. Levin, B. C., Gurman, J. L. , Paabo, M. , Baier, L. , and Holt, T.,

Toxicological Effects of Different Time Exposures to the Fire Gases:

Carbon Monoxide or Hydrogen Cyanide or to Carbon Monoxide Combined with

Hydrogen Cyanide or Carbon Dioxide, Proceedings of U. S. - Japan Panel

on Fire Research and Safety, Norwood, MA (1987)

7. Birky, M. M. , Preliminary Comparison of Combustion Model in Toxicity

Test Method with a Large Scale Fire Scenario, Fire Research and Safety,

J. E. Chidester, Ed., NBS SP639, U. S. Dept. Commerce, Nat'l. Bur.

Stand. (1982).

8. Levin, B. C., personal communication.

9. Levin, B. C., Paabo, M. , Gurman, J. L. , and Harris, S. E., Effects of

Exposure to Single or Multiple Combinations of Predominant Toxic gases

and Low Oxygen Atmospheres Produced in Fires, Fund. Appl. Tox. 9:236-250,

(1987) .

10.

Babrauskas , V. , Levin, B. C., and Gann, R. G., A New Approach to Fire

Toxicity Data for Hazard Evaluation, ASTM Standardization News 14:28-33.

(1986) .

42
Table 1

Test Plan for Single Compartment Experiments

Test # Samel e Combustion Mode

Within Room External Chamber

Number of

Animals

Exposure

Condition

Number of

Animals

Exposure

Condition

1 NFRa Smoldering 6 Smd 0 _ __ 2 FRb Smoldering 6 Sm 0

3 NFR Smoldering 2 Sm 18 Sm

4 FR Smoldering 2 Sm 18 Sm

5 NFR Flaming 0 18 Fl e 6 FR Flaming 0 18 FI

7 NFR Smolder/Flame c 2 Sm 18 FI

8 FR Smolder/Flame 2 Sm 18 FI

9 NFR Smolder/Flame 6 Sm 18 FI

10 FR Smolder/Flame 6 Sm 18 FI

a) NFR: Non- Fire Retardant

b) FR: Fire Retardant

c) Smolder/Flame: Smoldering- to-Flaming Transition Tests

d) Sm: Animals Exposed to Products of Smoldering Decomposition

e) FI: Animals Exposed to Products of Flaming Decomposition

43
Table 2 Construction Materials of Large-Scale Single Compartment Tests

Location Material Thickness

(mm)

Density

(kg/m3

) Ceiling and Wall Gypsum Board 12.7 930

substrate

Ceiling and Wall Calcium Silicate 12.7 720

interior finish

Floor substrate Concrete 102 2280

Floor interior Gypsum Board 12.7 930

finish

44
Table 3 Location of Instrumentation

Burn Room

Load Cell

load platform 06.

m

by 0.6m, 0.3 m from floor (1.23 m from north

wall and 2 . 16 m from east wall).

Thermocouple Trees

Tree 1 - Southeast corner (0.6 m from the south and east walls)

10 thermocouples; 0.15, 0.66, 0.97, 1.12, 1.27, 1.42,

1.57,

1.88, 2.03, and 2.15 m from the floor.

Tree 2 - Center of room (1.23 m from the north wall and 1.85 m

from the east wall)

10 thermocouples; 0.15, 0.66, 0.97, 1.12, 1.27, 1.42,

1.57,

1.88, 2.03, and 2.15 m from the floor.

Tree 3 - Northwest corner (0.6 m from the north and west walls)

10 thermocouples; 0.15, 0.66, 0.97, 1.12, 1.27, 1.42,

1.57,

1.88, 2.03, and 2.15 m from the floor.

Thermo couple

North Wall - 4 thermocouples end of animal holding tubes (0.3 m

from north wall and 0.3 m from ceiling).

2 thermocouples in burn room animal restrainers.

Animal Exposure Chambers - 3 thermocouples, one for each exposure

chamber

.

Smoke Meters

Vertical - 1 smoke meter (1.23 m from north wall and 1.39 m from

east wall)

.

Horizontal - 6 smoke meters (1.39 m from east wall)

0.61, 0.91, 1.22, 1.52, 1.83, and 2.29 m from floor.

Gas Probes

Burn Room - CO , C02

, 02 Ceiling - 0.3 m from the ceiling (1.23 m from

the north wall and 2.15 m from the east wall).

Floor - 0.3 m from the floor (0.6 m from the

south wall and 0.6 m from the west wall).

HCN

taken from animal exposure chamber sampling line.

Animal Exposure Chambers - CO, C02

, and 02, port for HCN.

45
Table 4

Average Initial and Maximum Mass Loss Rates for FR and NFR

Polyurethane Foam and Cotton Fabric Cushion Assemblies Exposed

to a Smoldering Cigarette

Material Test #

Averase Mass

Initial

Loss Rate (me/s)

Maximum

Material0 Consumed (%)

NFRa 1 56 320 35

3 53 570 56

FRb 2 29 120 26

4 36 130 33

a) Non- Fire Retarded Foam

b) Fire Retarded Foam

c) mass consumed/initial mass

46
Table 5 Extreme Gas Concentrations of CO, C02

, and 02 Near the

Burn Room Ceiling During Smoldering Combustion

Material

Test

Number

Time3 (s)

Maximum

CO

(ppm) co2 (%)

Minimum

o2(%)

NFRb 1 7000 2300 0.6 19.8

3 6119 4800 0.9 19.1

FR° 2 7950 2100 0.6 20.1

4 9391 2900 0.8 19.9

a) Time of maximum CO concentration

b) Non-Fire Retarded Foam

c) Fire Retarded Foam

47
Table 6

Extreme Gas Concentrations of CO, C02

, HCN, and 02 Near the Burn

Room Ceiling During Flaming Combustion of Cushion Assemblies

Maximum Gas Concentration and Time Minimum

CO Time3 co2 Timeb HCN Time0 °2 Timed Material Test # (ppm) (s) 1%1 (s) (ppm) (s) (%) (s)

NFRe 5 5900 1800 7.1 1440 104 1440 11.4 1440

FRf 6 4600 2460 4.3 2160 168 1920 14.7 2160

Time to:

a) Maximum CO

b) Maximum C02 c) Maximum HCN

d) Minimum 02 e) Non-Fire Retarded Foam

f) Fire Retarded Foam

48
Table 7

Average Mass Burning Rate for FR and NFR Cushion Assemblies

During Smoldering and Flaming Decomposition

Mass Loss Rate (mg/s)

Smoldering Flaming

Material Test # Initial Maximum Maximum

NFRa 7 56 290 1820

9 48 220 2120

FRb 8 31 130 3400

10 32 120 2830

a) Non- Fire Retarded Foam

b) Fire Retarded Foam

49
Table 8

Material Test #

Comparison of the CO,

Yields for the Large

CO (kg/kg)

co2

, -Scale

CO,

and HCN Gas

Fire Tests

(kg/kg) HCN (kc/kc)

Smolder Flame Smolder Flame Flame

NFRa 1 0.08 0.4

3 0.11 — 0.3 — —

5 — 0.09 — 1.9 2 x 10" 3 7 0.08 0.11 0.4 2.6 3 x 10" 3 9 0.07 0.12 0.4 2.2 3 x 10' 3

FRb 2 0.11 — 0.5 —

4 0.08 — 0.5 — —

6 — 0.10 — 1.3 4 x 10' 3

* 8 0.14 0.15 0.7 CM CM 1 x 10' 2 10 0.11 0.11 0.6 2.1 1 x 10' 2

a) Non-Fire Retarded Foam

b) Fire Retarded Foam

50
o

§•

<D H

O cd wo wo co o

CO CO CO CO CO CO <N wo

'a- ^a- WO CD CO CO o

-aCO 00 00 00 O) 0)0)0)0 0) O CD O O

o o o o o o

o o o o o o o o o o o o

n wo r-* s r** o N CO CO CO CO CO

°-°o k

§ ° §

o o o o o o

o o o o o o o o o o o o

<N' O S' o >

o g| U p\

S w

m vo in m m

o o o o o o

eg eg eg CM CM CM

o o o o o o

O O O WO O wo o o wo o eg WO CD CD CD rv CO

o eg co co co wo

> > T3 T3 T3 T3

•H *H © (D CD CD

i—4 *—4 »H *h -h *h < < Q Q Q Q

O O O O O O

o rv o co

eg co h t-i eg o

(D CD N N N

ih cd wo co -a- eg

eg co rH tH o o

eg wo

w-> CD wo wo

co j) O T3 »

51
*H CO

CO CO

O

O

o a] u o

*8 I

ID N H H H

o o o o o o

eg eg eg eg cm <n

o o o o o o

o o o o o o

o o o o o o

co ^ m oo o) o)

N ^ (D O) O)

e

°-°o k

l ug

C/3

o o o o o o

o o o o o o

o o o o o o

E o a u a

•H T3 3 §

> a)S w

CO ID ID in o o o o o o N N N CM N N

00 CD o o

(N CSJ

o o o o o o

o o o o o o

cm cd >r m cd id

T3

a) <d <v a) > > > > T3 TJ

•H iH >H «H 0) 0) i—I r-H »—I *tH tI < < < < Q Q

o o m m m m

(D < CM H 0) O)

co m cm co cm cm

>T CD N N CO CO

H CO m CM CD -sf

T3 T3 (D a) •H *H Q Qo T5 0 0

•H fH Q Q

c

03 -H -H M CCD H 03 03 CD

03 O TJ (1)

<4-1

52
Conditions

in

Animal

Exposure

Chambers

and

Animal

Responses

During

FR

and

NFR

Smoldering

Combustion

Exposures

T3P

P i

• co P P

P co * H o w

CL, O

z

T3P c

•rl •H • Q d3 P P X

O •P Ed Z &

o\wo o

o o o

\w^ VO vD O 1—1 CM

vO VO vO o o o

vO vO VO \o

wo o

Z E

o p

33 P

COC

o

•rH p

cOP

P

e <N &> p o

o

c

oo

CO

cO o O <#> U v— p

bC l cOP

P

><

o

o

E

P

P

co o m

CM i—l

vo in i—i

oo <t i—

i

O i—l i—

i

O o o

o o o

CO CO 00 H co co

vo in

CO VO O'

Cv 0"v Cv

i—I i—I i—l

co in vo o o o

o o o

o o o

co o CM

1—1 CM CM

COC

O bO O C

•P

CO w

CO cO E

cO O v • S hJ

in o cm

i—l CO CO

co o 1—1 CM CM

co

•rHp

p

4J

CO S

o3 Epz

rQod

Ed

Itp

copH

CO <}

p

C

cO d)P

cO P

P

04PP

*rHc

O

z

p

e

CO -dp

CO P

P

OJP

P

•rH

CO rO

53
Conditions

in

Animal

Exposure

Chambers

and

Animal

Responses

During

FR

and

NFR

Flaming

Combustion

Exposures

TO

CD P i • V) P P

<D W X H O fa fa O

z

TO

(D G

•rH •rH • Q X P P X

O •H W

Z &

z e o Pi X P

cn] df> O

vO vO vO \\\ o o o

vOw\vO vO o m vo

W\VO vD VO

<-l o o

vo VO vO \1—I VOwVO

vo vo vO \o

W

o o

\wvo vo vO O O vo

in cm

CM VO VO

LO r— t—

I

vo CO vO

O rP ON

-cj- r~— r~~-

cm cm m

r- m oo

CM H CM

cn in

cm o O

ov rv oo

On

Dd

fa

1

z

w\vO vO vO o o o

w\vO vO vO o m

vo vo vo \o Wo o

vO\wvO vo

VO vo vo

vo vO vo \\\ o o o

vo vo vo O vo vo

ON CM CO

vo co rv

O 1-1 o

CO vo CO

o o o

r". o o I—I CM CM

in co cm

vo ^ CO

CM ON ON O i—( VO

i—l CM t—

I

vO O i-l on rCfl eg,— co CM O on in O r". in co m 1 f". CO rH r'-* e> o <*> • • • 1 • • • • u — CO in VO CO rH co CO CM CO <f CO 1 m rH CO CO

CDu 1 cfl i-i CD><

s O o O o o o o o o O o o o o o o o o

O P o o o o o o o o o o o o o o o o o o

O P <1- rH rH co CM CO m m CO ON O r- CM o rH

rH

1

CM CM vO rH CO vO rH iP CO CO <! vO rH CO

10C 0) o b0 P CN] CJ C ^ T3 TJ TJ TJ C O

*H \ On CO On in CM ON o rH ON m co o in co o CO CM CD

CO TO bJi l CM CO CO m vo rH rH CM CO m m CM CO E 4-1 CO cfl E •H O

cfl o ^ i-l Z fa o <d e

E E E E fa O

cfl cfl cfl cfl X -H tp b0 r-l rH bO rH rH fa P

O P C fa fa P fa fa •rH E •H \ \ •rH \ \ bD Ti

CD O e TO TO E TO TO C TO TO O Cfl rH rH cfl rH rH •iH O CD rH o o rH o o P E

S Q fa E E fa E E c Cfl CD co co co co cfl rH r£l TO fa p

VO

fa

i-l P

cfl c P cfl a) TO

fa i-l co

0) 4-> U 0) •H fa fa

i a) c u

O *r-l Z fa

0 i-l P o

1 Cp

b£) C TO

a) p

o

<du

u

o

u

<1) TO

i—

l

O

£

co o

cfl X O T)

54

e)

Instrument

failure
Table 13

Comparison of C02 /C0 and HCN/CO Yield Ratios for Single Compartment,

and Multi -Compartment Large-Scale Tests with the NBS Toxicity Protocol

for Non-Fire Retardant (NFR) and Fire Retardant (FR) Foams

Combustion

Mode

Test

Environment

Cotton

Cover

Material

NFR FR

co2 /CO HCN/CO co2 /CO HCN/CO

NFa NBS Tox Prob _h 7 0.01 8 0.01

S

c Multi -Comp +

1 _ d - - - S Single Comp + 5 ND® 6 ND

F

f NBS Tox Pro - 80 0.10 30 0.12

F Multi -Comp + 70 0.01 40 0.01

F Single Comp + 20 0.02 15 0.03

S/Fg NF NBS Tox Pro - ND ND ND ND

S Multi -Comp + 7 <0.01 5 <0.001

S Single Comp + 5 ND 5 ND

S/F Rj NBS Tox Pro _ ND ND ND ND

F Multi -Comp + 30 0.04 20 0.03

F Single Comp + 20 0.03 20 0.08

a) Non-Flaming (i.e., pyrolytic combustion)

b) NBS Toxicity Protocol

c) Smoldering Combustion

d) Test Not Performed

e) Not Determined

f) Flaming Combustion

g) Smoldering- to -Flaming Combustion results

reported individually

as smoldering phase and flaming phase

h) cotton cover fabric not present

i) cotton cover fabric present

j ) Ramped heating from NF state

55
Table 14

Comparison of CO, CO2

, and HCN Average Yield Values for Single Compartment,

and Multi -Compartment Large-Scale Tests with the NBS Toxicity Protocol

for Non-Fire Retardant (NFR) and Fire Retardant (FR) Foams

Combustion

Mode

Test EnvironmentCotton

Cover Material

NFR FR CO CO

2 HCNk CO C°2 HCN^

(kg/kg) fog/kg? (kg/kg) (kg /kg) (kg/kg) Cka/kg?

NFa NBS Tox Prob _h 0.03 0.2 4 x lO

-4 0.04 0.3 3 x 10~

S

c Multi-Comp +

1 _d - - - - - S Single Comp + 0.09 0.4 - 0.11 0.6 -

F

f NBS Tox Pro - 0.02 1.6 2 x

10" 3 0.05 1.6 6 x 10“ F Multi-Comp + 0.04 2.9 2 x 10 4 0.06 2.2 4 x 10 F Single Comp + 0.11 2.2 2 x 10 3 0.12 1.9 4 x 10

S/Fg NF NBS Tox Pro - ND ND ND ND ND ND

S Multi-Comp + 0.15 1.0 <1 x 10

4 0.17 0.7 <1 x 10 S Single Comp + 0.08 0.4 - 0.13 0.7 -

S/F R

j NBS Tox Pro - ND ND 1 x

10~2 ND ND 1 x 10" F Multi-Comp + 0.09 2.8 2 x 10 4 0.12 2.7 4 x 10 F Single Comp + 0.40 2.4 3 x 10 3 0.13 2.2 1 x 10

a) Non-Flaming (i.e., pyrolytic combustion)

b) NBS Toxicity Protocol

c ) Smoldering Combustion

d) Test Not Performed

e) Not Determined

f) Flaming Combustion

g) Smoldering-to-Flaming Combustion results

reported individually

as smoldering phase and flaming phase

h) cotton cover fabric not present

i) cotton cover fabric present

j ) Ramped heating from NF state

k) Values taken from previous report [1] have been

rounded-off to more accurately reflect measurement

accuracies

.

56
Table 15

Comparison of N-Gas Model Calculations with Chemical and Toxicological Results in Animal Exposure

Chambers for Single Compartment Tests and Selected Multi-Compartment and NBS Toxicity Protocol

Tests for Non-Fire Retardant (NFR) Foam alone and in Combination with Haitian Cotton Cover Fabric

Prediction

Average Gas Concentration No. Died/No. Tested Latest N-Gas Model

Mode of CO co2 °2 HCN Within Post Day of WithinDecomposition Source (ppm) (%) m (ppm) Exp Exp Death Exp+2A hrs

Smoldering Chair3 150 0.3 20.6 NDf 0/6 0/6 0.02

700 0.5 20.3 2 0/6 0/6 — 0.11

1050 0.8 20.2 ND 0/6 0/6 — 0.17

Smoldering Cushion*3 1300 0.8 19.6 3 0/6 . 0/6 — 0.31

3800 1.1 19.1 20 0/6 1/6 1 0.83 3300 1 . A 18.5 15 2/6 0/6 — 0.8A

Non-Flaming Foam0 710 0.5 20. A 10 0/6 1/6 28 0.35

1160 0.3 20. A 11 0/6 2/6 2 0.35

1A00 0 . A 20.2 — 0/6 3/6 8 0 . A0

Non-Flaming Cotton0 2050 1.1 20.1 — 0/6 A/6 3 0.A8

2570 1.2 19.7 — 0/6 5/6 1 0.61

3200 1.5 19.6 ““ 0/6 A/6 2 0.77

Flaming Chair3 ,d — — — — — — — —

Flaming Cushion*3 1A00 3.8 16.5 25 0/6 0/6 ___ 0.75 2100 5.2 13.7 62 5/6 0/6 — 1 . A0 A100 6. A 16.1 67 6/6 0/6 — 2.01

Flaming Foam0 320 2.3 18. A 8 0/6 0/6 ___ 0.08

A20 2.7 17.7 — 0/6 0/6 — 0.11

670 3.1 17.2 — 0/6 0/6 — 0.73

Flaming Cotton0 900 e 18.9 <1 0/6 0/6 ___

1070 2.9 18.1 — 0/6 0/6 — 0.30

1A80 3.1 17.5 2 0/6 0/6 — 0 . A3

Smoldering/ Chair3 2050 A.

5

15.6 20 3/6 1/6 1 0.95 Flaming 1810 7.5 13.0 119 6/6 0/6 — 1.95

Smoldering/ Cushion*3 1500 1.5 19.2 32 0/6 0/6 — 0.56 Flaming 2800 3.0 17.2 A0 1/6 1/6 1 1.0A 3500 3.0 17.0 51 0/6 0/6 — 1.26

A200 A.

7

15.2 71 6/6 0/6 — 1.83 6800 3.7 18.0 72 6/6 0/6 — 2.09

6300 A.

9

18.5 72 6/6 0/6 — 2.21

Ramped-2 Phase Foam0 2160 0 . A 20.2 91 3/6 3/6 A 0.95 Heating 21A0 0.5 20.0 90 0/6 2/6 1A 0.96

3380 0.6 19.8 156 6/6 0/6 0 1.58

a) Burn Room, Multi -Compartment Test

b) Bum Room, Single Compartment Test

c) NBS Toxicity Protocol

d) Not Tested with Animals

e) Instrument Failure

f) Not Detected

g) HCN not measured during animal

tests, but analytical results showed HCN less than A A ppm

57
Table 16

Comparison of N-Gas Model Calculations with Chemical and Toxicological Results in Animal Exposure

Chambers for Single Compartment Tests and Selected Multi-Compartment and NBS Toxicity Protocol

Tests for Fire Retardant (FR) Foam alone and in Combination with Haitian Cotton Cover Fabric

Prediction

Average Gas Concentration No. Died /No. Tested Latest N-Gas Model

Mode of CO co2 °2 HCN Within Post Day of WithinDecomposition Source (ppm) (%) (%) (Plan) Exp Exp Death Exp+24 hrs

Smoldering Chair3 420 0.3 20.6 <1 0/6 0/6 0.06

700 0.4 20.3 2 0/6 0/6 — 0.11

1100 0.7 20.4 ND 0/6 0/6 — 0.17

Smoldering Cushion*5 1300 0.3 19.8 4 0/6 0/6 — 0.27 2000 0.5 19.6 6 0/6 0/6 — 0.40 2200 0.6 19.9 5 0/6 0/6 — 0.41

Non-Flaming Foam0 700 0.3 20.5 1 0/6 2/6 2 0.15

860 0.4 20.4 5 1/6 5/6 10 0.19

880 0.3 • 20.4 2 0/6 4/6 5 0.19

Non-Flaming Cotton0 2050 1.1 20.1 — 0/6 4/6 3 0.48 2570 1.2 19.7 — 0/6 5/6 1 0.61 3200 1.5 19.6 — 0/6 4/6 2 0.77

Flaming Chair3 ’ d — — — — — — — —

Flaming Cushion*5 1700 2.7 18.0 69 0/6 0/6 — 0.95

1900 3.5 16.1 82 4/6 4/6 — 1.22 3000 4.3 18.0 73 5/6 5/6 — 1.33

Flaming Foam0 1000 2.0 18.5 80 1/6 1/6 13 0.76

1090 2.1 18.2 70 1/6 3/6 11 0.72

1280 2.8 17.6 140 2/6 3/6 1 1.23

Flaming Cotton0 900 e 18.9 <1 0/6 0/6 —

1070 2.9 18.1 — 0/6 0/6 — 0.30 1480 3.1 17.5 2 0/6 0/6 — 0.43

Smoldering/ Chair 3 2900 1.0 16.0 145 6/6 0/6 — 1.70 Flaming 2600 4.7 15.2 123 6/6 0/6 1.77

Smoldering/ Cushion*5 1700 1.3 19.6 102 0/6 0/6 1.01 Flaming 3700 3.5 16.5 170 6/6 0/6 — 2.12

4100 3.7 17.1 169 6/6 0/6 — 2.14 3000 3.1 17.0 219 6/6 0/6 — 2.22

4200 e 14.3 200 6/6 0/6 —

6400 5.7 18.2 200 6/6 0/6 — 3.21

a) Bum Room, Multi -Compartment Test e) Instrument Failure

b) Bum Room, Single Compartment Test f) Not Detected

c) NBS Toxicity Protocol

d) Not Tested with Animals

58
59

Figure

1.

Configuration

of

Test

Room

Showing

the

Sampling

Locations

for

Burn

Room

Animal

Exposures

and

Exposure

Chamber

Animal
2.44 m

AxV

CO00o&0coN

\—oXAx

COV 0k_ 0

k_D0) D O W CL O X

CL LU X

LU 76

76 E E c< c< E

4-^ o o

CM o

CM Oooo0c 0 0 CD c c c (/>

c?0

_q

Q-E F 0

Q_E0

CO

tn

U5Oo0o © © © o

Figure

2.

Schematic

Floor

Plan

of

Large-Scale

Single

Room

Compartment

Test

Facility

Showing

Instrument

Locations.
(a) ANIMAL RESTRAINING TUBE

(b) ANIMAL RESTRAINING TUBE PLACED IN ANIMAL HOLDING TUBE

Figure 3. Schematic Representation of Burn Room Animal Restrainers

Mounted in Burn Room Wall.

61
1400

o

C\J

OCD

OO

GO

cn

o

o Ljj CO

o

o

CM

(9) SS01 SSVW

Figure

4.

Mass

Loss

of

NFR

Cushion

Assemblies

During

Smoldering

Decomposition.
1200

63

Figure

5.

Mass

Loss

of

FR

Cushion

Assemblies

During

Smoldering

Decomposition

.
5000 (Wdd) N0LLVHIN3DN03 SYO

H

sM

Eh

<4-4 o

fjo

C/) 3

-2ou

bOc

a)

r—

4

o

c/5bOC

3Q

C

o

•r^ 4J

CO

5-i cuC

a) o

o

o

(4-4 o

c

o

M

54 T3

CO C

a co o cc

CJ Ct,

<D543

bO

Pt*

64

NFR

Cushion

Assemblies.
10000 (Wdd) N0LLVHIN3DN00 SVD

<po

o

•rH

4JW

3

rOo

CJbO3

•rHp

CD T3

r—

I

oS£

b£) 3

•rHP

3Q

3

O

•rH p

03P

<u£

0) CJ

CM O

CJtpo3

o

w

•rHp

cda

£

o

CJ

03P

3

b£l

•rH

t*4

65

FR

and

NFR

Cushion

Assemblies.
66

Figure

8.

Typical

Smoke

Layer

Development

for

FR

and

NFR

Cushion

Assemblies

Undergoing

Smoldering

Decomposition.
2500

G£

oo

cu (2) SSOl SSVPf

67

Figure

9.

Comparison

of

Mass

Loss

of

FR

and

NFR

Cushion

Assemblies

During

Flaming

Combustion.
7000

t

10

t

o

o

o

CO o

m

o

''t o

fO o o

CM (ujdd) NOIiVaiN33NOO SVO (2) N0liVdiN30N00 SVO

68

Figure

10.

Comparison

of

CO,

C02

, 0

2

,

and

HCN

Concentrations

During

Flaming

Combustion

of

FR

and

NFR

Cushion

Assemblies.
2.5 ooomoo

in

'tooooom

K)ooo

K)

69

Figure

11.

Comparison

of

Smoke

Layer

Development

During

Flaming

Combustion

of

FR

and

NFR

Cushion

Assemblies.
3000-r

3000t ootOCN o o O o o o o O o o

in o m o in

cs C>4

I— qs of4 z 4-> i j -a CA r*

CO

5-4 2 H

ao

M-l r* O •r4

(A CO

4-1 i—1

ca Ct, cu 1 H o

4-1 cu 1 4J ao

coa •n4

•rH 5-i <u a T3

<u r—

02 og

5-1 to o

4-1 aoC

(A •iH COo 3 J a

(A CA

to a>

co •rH s f-H X 44 g O 5

CA CA £3 CA 4J O < c

CA a) •H g

5-i O •rH CO •rH 5-4 a x CU E CA Cu O 3 X o CJ w

csi

<u

5-i 0

ao

•rH Uu

70
12000

o o

o o

(50 NOIlVaiN30NOO SVO (uidd) N0llVaiN30N03 SVO

(ujdd) N0llVaiN30N00 SVO (2) N0llVdlN30N00 SVO

71

Figure

13.

Comparison

of

CO,

C02

, 0

2

,

and

HCN

Concentrations

During

Replicate

Tests

of

NFR

Cushion

Assemblies.
12000

o

o

in

(Z) N0llVaiN33N03 SV3

O

o

T O

CN

O

o

o

1 1 1 1

1- o

o o o o o

o o o o

K) CN wdd) N0llVaiN33N03 SVO

o

o

O

O) CD K)

(uidd) N0llvaiN33N03 SVO (2) N0liVaiN33N03 SVO

72

Figure

14.

Comparison

of

CO,

C02

, 0

2

,

and

HCN

Concentrations

During

Replicate

Tests

of

FR

Cushion

Assemblies.
o

o

o

CN

o

o

o

cn

Ul

o

o

O LJ

CO —

o

o

o

fO

CN (w) 1H9I3H (UJ) 1H9I3H

73

Figure

15.

Comparison

of

Smoke

Development

During

Replicate

Tests

of

FR

and

NFR

Cushion

Assemblies.
Figure

16

.

Comparison

of

the

Average

Weight

Cain

for

Six

Caged

Animals

and

Two

Burn

Room

Control

Animals.
oot

o

o

CN

CE

l_L_ CE

O X O

CO

*

* * o

o O

o O

CM (000 i x U[LU-Ludd)

O

o

10

mO

CM o

CJ

oY> LO

75

Figure

17.

Comparison

of

the

Integrated

Pure

CO

and

CO

plus

Values

and

the

Burn

Room

Integrated

CO

at

Death.
FORM NBS-1 14A (REV. II -84) U.S. DEPT. OF COMM.

BIBLIOGRAPHIC DATA

SHEET (See instructions)

1. PUBLICATION OR

REPORT NO.

NBSIR-88/3764

2. Performing Organ. Report No. 3. Publ ication Date July 1988

4. TITLE AND SUBTITLE

LARGE-SCALE COMPARTMENT FIRE TOXICITY STUDY:

COMPARISON WITH SMALL-SCALE TOXICITY TEST RESULTS

5. author(S)

gm;Q Braun, Barbara C. Levin, Maya Paabo, Joshua L. Gurman , Helene M. Clark

Margaret F. Yoklavich

6. PERFORMING ORGANIZATION (If joint or other than N BS. see in struction s)

NATIONAL BUREAU OF STANDARDS

U.S. DEPARTMENT OF COMMERCE

GAITHERSBURG, MD 20899

7. Contract/Grant No.

8. Type of Report & Period Covered

9. SPONSORING ORGANIZATION NAME AND COMPLETE ADDRESS (Street. City. State. ZIP)

Consumer Product Safety Commission

Bethesda, Maryland 20207

10. SUPPLEMENTARY NOTES

T^YXXXgyxyxxyyxyYygXyxXX«^3rKX«XXXXXXXXXXgXKXX^XXXX^XXXXX«XXXXXXXgXXiXXXp[Xj(KX^XKXXgjC

| j Document describes a computer program; SF-185, FIPS Software Summary, is attached.

11. ABSTRACT (A 200-word or less factual summary of most significant information. If document includes a significant

bi bl i o graphy or literature survey, mention it here)

Ten large-scale single compartment fire tests were performed using two polyurethane foaus

and a cotton upholstery fabric. Animals were exposed to the products of decomposition

of cushion assemblies burned under three different combustion modes: 1 ) smoldering

combustion initiated by a cigarette; 2 ) flaming combustion initiated by a small natural

gas diffusion burner; 3 ) smoldering-to-flaming transition combustion initiated by a cigarette and forced into flaming combustion after a prolonged period of smoldering by a small natural gas diffusion burner. Comparison of gas yields (CO, CO 2 , and HCN) betweer

these tests and prior large- and small-scale tests showed that the CO and CO 2 yields

agreed within a factor of 3, while the NBS Toxicity Protocol produced 10 times more HCN

in the flaming mode and ramped heating mode .than the large-scale tests. Qualitatively,

animal deaths were limited to within-exposure plus 24 hrs for the large-scale tests,

while small-scale animal deaths occurred primarily post-exposure. Within the errors of

the NBS Toxicity Protocol (+ 5-10 mg/1), LC50 determinations in the large-scale tests

were comparable to the small-scale tests, exeept for the small-scale ramped two phase

heating and large-scale smoldering-to-f laming NFR tests. The N-gas model for 30 minutes

exposures was expanded to include 4 gases, CO, CO 2 , HCN and Reduced 02 * Model calculat

showed that within-exposure animal deaths in small- and large-scale tests correlated

with model values greater than 0.7. Burn room animal deaths could not be explained in

terms of the four gases used in the N-gas model.

] on

12. KEY WORDS (Six to twelve entries; alphabetical order; capitalize only proper names; and separate key words by semicolon s) Cotton; fire tests; large scale fire tests; polyurethane; small scale fire tests;

toxicity; upholstery.

13. availability

'~Xj Uni i m i ted _

For Official Distribution. Do Not Release to NTIS ~ Order From Superintendent of Documents, U.S. Government Printing Office, Washington, DC

20402.

“X Order From National Technical Information Service (NTIS), Springfield, VA 22161

14. NO. OF

PRINTED PAGES

83

15. Price

$13.95