Reference Publications A 11 10 4 0 517 5 2

NBSIR 82-2532

Further Development of A Test

Method for the Assessment of the

Acute Inhalation Toxicity of

Combustion Products

U S. DEPARTMENT OF COMMERCE

National Bureau of Standards

National Engineering Laboratory

Center for Fire Research

Washington, DC 20234

June 1 982

Report

5 DEPARTMENT OF COMMERCE

TIONAL BUREAU OF STANDARDS

NBSIR 82-2532

> 1

1 FURTHER DEVELOPMENT OF A TEST

METHOD FOR THE ASSESSMENT OF THE

ACUTE INHALATION TOXICITY OF

COMBUSTION PRODUCTS

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Barbara C. Levin, Andrew J. Fowell, Merritt M. Birky,

Maya Paabo, Alan Stolte, Dolores Malek

U S. DEPARTMENT OF COMMERCE

National Bureau of Standards

National Engineering Laboratory

Center for Fire Research

Washington, DC 20234

June 1 982

Report

U.S. DEPARTMENT OF COMMERCE, Malcolm Baldrige, Secretary

NATIONAL BUREAU OF STANDARDS, Ernest Ambler, Director
. .> y~?K XC-.
CONTENTS

Page

LIST OF FIGURES v

LIST OF TABLES viii

Abstract x

1.0 INTRODUCTION 1

2.0 A TEST METHOD FOR THE ASSESSMENT OF THE ACUTE INHALATION

TOXICITY OF COMBUSTION PRODUCTS 4

2.1 Scope 4

2.2 Significance and Use 5 2.3 Definitions 6

2.4 Applicable Documents 7 2.5 Summary of Test Method 8

2.6 Apparatus 8

2.7 Calibration 13

2.8 Animal Care 13

2.9 Test Specimen 13

2.10 Test Procedure 15

2.11 Reporting 19

2.12 Test Method Sensitivity and Limitations 21

2.13 Safety Considerations 22

3.0 COMBUSTION SYSTEM 23

3.1 Introduction 23

3.2 Static Versus Dynamic Combustion System 23

3.3 Radiant Versus Convective Heat 24

3.4 Preset Exposure Temperatures or Ramped Temperatures . . 26

3.5 One Temperature or Different Temperatures for all

Materials 27

3.6 Flaming and Non-Flaming Conditions 28

3.7 Sample Preparation 30

3.8 Pressure-Relief Panel 32

3.9 Summary of Combustion System 32

4.0 ANIMAL EXPOSURE SYSTEM 33

4.1 Criteria for an Exposure System 33

4.2 Whole Body Versus Head-Only Exposure of the Animals . . 33

4.3 Static Exposure Versus Dynamic Exposure 34

4.4 Exposure Chamber Design 37

4.5 Exposure Duration 39

4.6 Summary of Animal Exposure System 39

5.0 CHEMICAL MEASUREMENTS 40

iii
Page

5.1 Need 40

5.2 Instrumentation. ....... 41

5.3 NBS Results 44

5.4 Summary of Chemical Measurements 46

6.0 ANIMAL MEASUREMENTS ...... 47

6.1 Need for Animals 47

6.2 Test Animals 48

6.3 Biological Endpoints 50

6.4 Assessment of Materials that Release Toxicants Rapidly 60

6.5 Summary of Animal Measurements 62

7.0 BIOLOGICAL MEASUREMENTS 63

7.1 Blood Analysis 63

7.2 Correlation of COHb, CO, and Toxicity 65

8.0 SUMMARY OF CHANGES TO THE TEST METHOD 66

9.0 FUTURE WORK 68

10.0 ACKNOWLEDGMENTS 69

11.0 REFERENCES 70

xv
LIST OF FIGURES

Page

Figure 1. Exposure chamber. 74

Figure 2. Details of exposure chamber. 75

Figure 3. Pyrolysis/combustion furnace. 76

Figure 4. Schematic of animal restrainer. 77

Figure 5. Exposure chamber with separate furnace. 78

Figure 6. Radiant furnace cone. 79

Figure 7. Animal restrainer. 80

Figure 8. NBS exposure chamber temperatures at animal nose 81

levels. Top: maximum temperatures. Bottom:

average temperatures.

Figure 9. Chamber temperature at animal nose positions 82

during 30 minute exposure to flaming wool and

Douglas fir. (NBS data. Furnace temperature

for flaming wool was 675°C and for flaming

Douglas fir was 490°C.)

Figure 10. Schematic of NBS gas analysis system. 83

Figure 11. Carbon monoxide measurements averaged over the 84

30 minute f laming material decomposition plotted

against the mass loading/chamber volume. The

length of least squares linear regression line

denotes the range of mass loadings tested.

Figure 12. Carbon monoxide measurements averaged over the 85

30 minute non- flaming material decomposition plotted

against the mass loading/ chamber volume. The length

of the least squares linear regression line denotes

the range of mass loadings tested.

Figure 13. Hydrogen cyanide measurements averaged over the 86

30 minute flaming material decomposition plotted

against the mass loading/chamber volume. The length

of the least squares linear regression analysis line

denotes range of mass loadings tested.

Figure 14. Hydrogen cyanide measurements averaged over the 30 87

minute non- flaming material decomposition plotted

against the mass loading/chamber volume. The length

of the least squares linear regression analysis line

denotes range of mass loadings tested.

v
Page

Figure 15. Overloading of furnace capacity as seen with

non-flaming decomposition of Douglas fir in

the NBS large furnace. Small furnace had

similar results.

Figure 16. Overloading of furnace capacity as seen with

flaming decomposition of Douglas fir in the

NBS small furnace. Similar results were seen with large furnace.

Figure 17. Carbon monoxide generation from ILE materials

decomposed in the non-flaming mode at various

mass loadings (NBS results)

.

Figure 18. Hydrogen cyanide generation from ILE

nitrogen-containing materials decomposed in

the non-flaming mode at various mass loadings

(NBS results)

.

Figure 19. Hyperbola depicting asymptotes approaching

a threshold mass loading at 30 minutes and a threshold time-to-incapacitation.

Figure 20. Time- to-incapacitation vs mass loading/chamber

volume hyperbolas for Douglas fir in the non- flaming mode from six laboratories. (Symbols

refer to the mean and standard deviation of the

times-to-incapacitation of the 6 animals tested

at each mass loading.)

Figure 21. Concentration-response curves resulting from

animal incapacitation, death within exposure

(30 min) and death both within and postexposure (30 min + 14 days) from the thermal

decomposition of wool in the flaming mode.

Figure 22. Concentration- response curves depicting

importance of slope information, i.e., LC^

data are the same, but the effective

concentration range differs.

Figure 23. Comparison of materials by their EC 50 J LC 50

(30 min) and LC 50 (30 min + 14 days) after

f 1 aming decomposition (NBS data) . (Symbols

referring to the same material are connected

by lines for easier identification and not to

imply a mathematical functional relationship.)

88

89

90

91

92

93

94

95

96

vi
Page

Figure 24. Comparison of materials by their EC^q, LC^q 97

(30 min) and LC50 (30 min + 14 days) after

non-flaming decomposition (NBS data) . (Symbols

referring to the same material are connected by

lines for easier identification and not to imply

a mathematical functional relationship.)

Figure 25. Three dimensional representation of the 98

relationship between concentration, time, and

lethality. (Figure modified after Packham and

Hartzell [24].)

Figure 26. Within- and post-exposure changes in carboxy- 99

hemoglobin and oxyhemoglobin in live cannulated

rats after a 30 minute exposure to an average

concentration of 4100 ppm of carbon monoxide.

Figure 27. Effect of blood sampling before end of exposure 100

(cannulated animals) and after exposure (noncannulated animals) . Results from Douglas fir

in the non-flaming mode from seven laboratories.

Figure 28. Determination of percent carboxyhemoglobin at 101

EC 50 , LC50 (30 min) , and LC 50 (30 min + 14 days)

from blood values obtained at various mass

loadings. (NBS data from flaming red oak.)

Figure 29. Relationship between carboxyhemoglobin and carbon 102

monoxide at the LC^q (30 minutes + 14 days) for

eleven materials (NBS data)

.

vii
LIST OF TABLES

Page

Table 1 . Participants of the Ad Hoc Working Group. 103

Table 2. List of Materials. 105

Table 3. Interlaboratory Evaluation of Douglas Fir. 106

Table 4. Modification of the Experimental Procedure. 107

Table 5. Toxicity of Modacrylic at Different Temperatures. 108

Table 6 . Single Versus Multiple Pieces of Douglas Fir. 109

Table 7. Maximum Chamber Temperatures During Animal Exposures

.

110

Table 8. NBS Carbon Monoxide Production per

TT . Mass Loading

nl Chamber Volume'

111

Table 9. NBS Carbon Dioxide Production per

y

Mass Loading

Chamber Volume'

112

Table 10. NBS Hydrogen Cyanide Production per

. Mass Loading

nlt Chamber Volume'

113

Table 11. Minimum Average Oxygen Concentrations. 114

Table 12. Incapacitation Times After Exposure to NonFlaming PVC.

115

Table 13. Constants for Time-Concentration Hyperbolas

(Y = Q + R/X)

.

116

Table 14. EC^q Values in mg/£. 117

Table 15. Slopes of EC^g Concentration-Response Curves. 118

Table 16. LC^q (30 minutes) values in mg/£. 119

Table 17. LC^q (30 minutes + 14 days) in mg/£ (95%

Confidence Limits)

.

121

Table 18. Slopes of 30 Minutes (95% Confidence

Limits of Slope)

.

123

Table 19. Slopes of 30 Minutes + 14 Days (95%

Confidence Limits of Slope)

.

125

viil
Page

Table 20. Comparison of NBS EC^ and LC,_q Values. 127

Table 21. Comparison of the Normalized Flaming LC^q and

EC<.q Data from all Laboratories.

128

Table 22. Comparison of the Normalized Non-Flaming LC^

and EC^q Data from all Laboratories.

129

Table 23. Comparison of the Normalized LC^^ and EC,_q

Data at 440°C from all Laboratories.

130

Table 24. NBS 10 Minute Test @ 30 mg/£. 131

Table 25. Carboxyhemoglobin and Gas Concentration Values

at LC^q (30 min + 14 days) - Flaming Combustion.

132

Table 26. Carboxyhemoglobin and Gas Concentration Values

at ECj.q (30 min + 14 days) - Non-Flaming Combustion.

133
FURTHER DEVELOPMENT OF A TEST METHOD FOR THE ASSESSMENT OF

THE ACUTE INHALATION TOXICITY OF COMBUSTION PRODUCTS

Barbara C. Levin, Andrew J. Fowell, Merritt M. Birky*,

Maya Paabo, Alan Stolte, Dolores Malek**

Abstract

This report describes the development of a test method for the

assessment of acute inhalation toxicity of combustion products of

materials. The procedure is primarily intended for research and

screening purposes. It provides: 1) a method for determining, under

flaming and non-flaming conditions, an LC<.q (the concentration of

combustion products which causes 50% lethality in the test animals

(rats) exposed for 30 minutes and observed for 14 days following

exposure); 2) an optional procedure to examine materials which rapidly

produce combustion products which cause death of test animals within

a 10 minute exposure and a 14 day post-exposure observation period;

and 3) a description of analytical and physiological measurements

which can provide more detailed information on the nature of the

toxic effects of combustion products. Limitations of the test

method are identified and future work to address them is proposed.

The participation through the direct exchange of technical

information of organizations representing academia, industry, and

other agencies of the United States Government is acknowledged.

Key Words: combustion products; flaming combustion; inhalation;

materials; non-flaming combustion; test method; toxicity.

* Current address: The Foundation for Fire Safety, Suite 1508, 1700

North Moore Street, Rosslyn, VA 22209.

**Guest Worker: Physiology Dept., School of Medicine and Health Sciences,

The George Washington University, Washington, D.C. 20006.

Current address: Graduate School of Public Health, University of

Pittsburgh, Pittsburgh, PA 15261.

x
FURTHER DEVELOPMENT OF A TEST METHOD FOR THE ASSESSMENT OF

THE ACUTE INHALATION TOXICITY OF COMBUSTION PRODUCTS

1 . 0 INTRODUCTION

The United States and Canada have higher fire fatality rates than

any of the other industrialized countries from which comparable data are collected [1]\ In 1979, the U.S. had 7800 reported fatalities, 31,000

people injured and over 5 billion dollars in property damage due to

fires [2].

Most fire deaths occur in homes from either smoldering combustion

or a large, flaming room fire. Eighty percent of these deaths are due

to the inhalation of smoke or hot gases and are not a result of burns.

Carbon monoxide has been imputed to be the primary cause of these

fatalities. However, the production of other toxicants in addition to

carbon monoxide during the thermal decomposition of materials prompted

the National Bureau of Standards to develop a method of assessing

the toxicity of combustion products. Requests to develop a test method

came from model code officials who had provisions in their codes controlling production of fire gases but no test methods to assess the toxicity

of combustion products, and from industry which had no means of screening

their products.

Extensive state-of-the-art reviews of the hazards of smoke inhalation were sponsored by the National Aeronautics and Space Administration

in 1977 [3] and by the National Academy of Sciences in 1978 [4]. Also

in 1977, the National Academy of Sciences published a review of factors

to be considered when evaluating the toxicity of pyrolysis and combustion

products [5]. These reviews have been influential in the evolution

of this test method.

Numbers in brackets refer to the literature references listed at the

end of this report.

1
The early development of this test method was supported by the

Products Research Committee (PRC) which was formed in 1974 by the Federal

Trade Commission and twenty-five representatives from the cellular plastics industry [6]. The committee consisted of members with expertise in

the scientific, engineering, and commercial aspects of cellular plastics

and were selected from academia, industry, and government. The mission

of the PRC was to administer a research program through grants to investigate the behavior of cellular plastics in fire, especially in areas of

fundamental research, small and large scale testing, and toxicity of

combustion products. Under the. sponsorship of the PRC, a small-scale

test procedure consisting of a combustion system, a chemical analysis

system, and an animal exposure system was designed and tested. The

results of this early work have been published as a report of the

National Bureau of Standards [7].

An interagency governmental meeting was held by NBS in January 1976

to examine the concerns and programs of various agencies in the area of

combustion toxicology. The objective of this initial planning meeting

was to focus on the needs of the agencies and to avoid unnecessary

duplication of efforts within the government. Agencies represented at

this initial meeting were the Consumer Product Safety Commission (CPSC)

,

Department of Defense (DOD) , Department of Transportation (DOT)

,

Environmental Protection Agency (EPA) , Energy Research and Development

Administration (ERDA) , Federal Aviation Administration (FAA) , National

Aeronautics and Space Administration (NASA), National Bureau of Standards

(NBS), National Center for Toxicological Research (NCTR) , National

Institute of Environmental Health Services (NIEHS) , and the National

Institute for Occupational Safety and Health (NIOSH)

.

An ad hoc working group was formed by NBS in November 1977

consisting of members from approximately 20 academic, industrial, or government organizations engaged in work relevant to the subject area. The purpose of this group was to provide a forum for exchanging technical

information to assist the National Bureau of Standards in the development

2
of a small-scale laboratory test to assess the Inhalation toxicity of

combustion products. The organizations that participated and their representatives are listed in table 1. The National Bureau of Standards is

grateful for the helpful advice, time, and expense that the members of the

working group donated in their efforts towards the development of this

test method. The acknowledgment, however, of the participating organizations is not intended to imply endorsement of the test method by those

organizations

.

Seven members of the ad hoc working group participated in an interlaboratory evaluation (ILE) of the test method proposed originally. (The

original method, in Appendix A of reference [7], should be distinguished

from the method presented in section 2 of the present report. The earlier

method was evaluated in the ILE and resulted in the procedure of section

2. (See section 8 for a summary of the changes.) The objectives of the

ILE were to determine the operability of the procedure and to determine

the reproducibility of the test results from different laboratories.

Twelve materials (table 2) , representing a wide variety of products (both

natural and synthetic), were examined by the participants in the ILE.

The detailed description and results of the ILE will be presented in a report titled "The Interlaboratory Evaluation of the NBS Toxicity Test

Method" (NBS report, in preparation). Some of the ILE data are also

presented in this report for illustrative purposes.

Throughout the development of the test method, the experimental

results from the participants of the ILE were presented at the ad hoc

working group meetings to help solve technical issues pertaining to the

methodology of the test. In addition, other members of the ad hoc

working group who were using other experimental systems also tested

many of the 12 materials. The consequence of this continuous input of

data on the identical materials was that the proposed method being tested

by the ILE was not a static procedure, but rather an evolving one.

3
The resulting test method, which is presented in section 2 of this

document, provides a means of assessing the acute inhalation toxicity of

the combustion products of materials under specified laboratory conditions and is primarily intended for research and preliminary screening

purposes. Additional factors must be considered in evaluating the

potential toxic hazard posed by a material in a given situation. Some

of these factors are listed in the section of the test method pertaining

to significance and use. Therefore, the results of this test method must

be combined with other information when making decisions about the

suitability of materials for specified uses.

In what follows, the resultant test method is described in section

2 and the rationale for the key provisions is discussed in detail in the

following sections.

2.0

A TEST METHOD FOR THE ASSESSMENT OF THE ACUTE INHALATION

TOXICITY OF COMBUSTION PRODUCTS

2.1

SCOPE

2.1.1 This laboratory test method is designed to assess the acute

inhalation toxicity of products resulting from the combustion or other

thermal degradation of materials.

2.1.2 Measurements are made under conditions of flaming combustion

and non-flaming pyrolysis, which are two key degradation modes encountered

in fires.

2.1.3 The test procedure provides a method for determining an the amount of material which produces sufficient combustion products

to cause 50% lethality in the test animals (rats) during a 30 minute

exposure and a 14 day post-exposure observation period. The experimental

results include the concentration-response curve and its slope.

4
2.1.4 The test method also describes an optional means to examine

materials which at a 30 mg/£ mass loading /chamber volume produce concen- trations of combustion products that cause death within a 10 minute

exposure and a 14 day post-exposure observation period*

2.1.5 Additional analytical and physiological measurements are described which can provide more detailed information on the nature of

the toxic effect.

2.2

SIGNIFICANCE AND USE

2.2.1 The test method provides a means of assessing the acute

inhalation toxicity of the combustion products of materials under specified laboratory conditions and is primarily intended for research and

preliminary screening purposes.

2.2.2 Additional factors that must be considered in evaluating the

toxic hazard posed by a material in a given situation include, among

others: the quantity of material present, its configuration, the proximity of other combustibles, the volume of the compartments to which the

combustion products may spread, the ventilation conditions, the ignition

and combustion properties of the material (s) present, the presence of

ignition sources, the presence of fire protection systems, and the

building occupancy.

2.2.3 Therefore, the results of this test method must be combined

with other pieces of information if making decisions about the suitability of materials for specified uses.

2.2.4 The analytical and biological measurements can provide

improved understanding of the mechanisms of toxic action. Such information will be helpful in determining the need for further research on specific materials.

5
2.2.5 The test procedure provides a uniform method of reporting

combustion toxicity data developed under laboratory conditions. This

will facilitate communication between workers in the field, promote

progress in research, and aid in the establishment of a self-consistent

data base of combustion product toxicity information.

2.2.6 The thermal exposure conditions employed in the test represent severe fire situations but do not simulate all possible fire scenarios.

2.3

DEFINITIONS

Definitions specific for this test:

2.3.1 Acute Toxicity: harmful effects of a single short exposure

to combustion products generated by the thermal degradation of materials.

2.3.2 Toxic Hazard: material and environmental conditions which

increase the probability that a toxic atmosphere will occur and an injury

will result.

2.3.3 Mass Loading: amount of material loaded in furnace in grams.

2.3.4 Concentration: mass loading per unit of exposure chamber

volume, expressed in mg/£.

2.3.5 Concentration- response: concentration plotted against the

percentage of animals that die during the 30 minute exposure and 14 day

post-exposure period.

2.3.6 LC^: concentration that is determined statistically to

produce death in 50% of the test (animal) population exposed for 30

minutes and observed for a period of 14 days.

2.3.7 Auto-ignition Temperature: the lowest furnace temperature

at which a material sample introduced into the test furnace will spontaneously ignite within 30 minutes.

6
2.4

APPLICABLE DOCUMENTS

2.4.1 Birky, M.M. ; Paabo, M. ; Levin, B.C.; Womble, S.E.; Malek, D.

Development of a recommended test method for toxicological assessment of

inhaled combustion products. (U.S.) NBSIR 80-2077; 1980, Sept. 63p.

2.4.2 Good Laboratory Practices. Federal Register, 4J3: 59986;

1978, Dec. 22.

2.4.3 Irwin, S. Comprehensive observational assessment: IA. A

systematic, quantitative procedure for assessing the behavioral and

physiologic state of the mouse. Psychopharmacologia, 1J3: 222-257; 1968.

2.4.4 Litchfield, J.T.

,

Jr; Wilcoxon, F. A simplified method of

evaluating dose-effect experiments. J. Pharmacol, and Exp. Therapeut

,

96^: 99-113; 1949.

2.4.5 Lyons, J.W.

;

Fristrom, R.M.

;

Becker, W.E.; Clayton, J.W.

;

Emmons, H.W.

;

Glassman, I.; Graham, D.L.

;

Long, R. ; McDonald, D.W.;

Nadeau, H.G. Fire research on cellular plastics: The final report of

the Products Research Committee. Washington, D.C., 1980, 213p.

2.4.6 MacFarland, H.N. Respiratory toxicology, chapter 5 in Essays

in Toxicology, W. Hayes, ed. New York: Acad. Press; 1_ : 121-154; 1976.

2.4.7 Packham, S.C.; Frens, D.B.

;

McCandless, J.B.; Petajan, J.H.;

Birky, M.M. A chronic intra-arterial cannula and rapid microtechnique

for carboxyhemoglobin determination. J. Comb. Tox. _3: 471-478; 1976.

2.4.8 Potts, W.J.; Lederer, T.S. A method for comparative testing

of smoke toxicity. J. Comb. Tox. 4_: 114-162; 1977.

2.4.9 Standard guide for measurement of gases present or generated

during fires. ASTM Standard E 800-81; 1981.

7
2.4.10 Committee on Fire Toxicology. Fire toxicology: methods

for evaluation of toxicity of pyrolysis and combustion products. Report

No. 2, Nat. Acad. Sci., Washington, D.C., 1977 August, 34 p.

2.5 SUMMARY OF TEST METHOD

2.5.1 A small scale laboratory test method has been developed to

assess the acute toxicity resulting from the inhalation of the products

of materials combusted or thermally degraded under specified conditions.

2.5.2 The test apparatus consists of 3 major components: (1) a combustion system, (2) a chemical analytical system, and (3) an animal

exposure system. The toxicity of the combustion products is determined

after pyrolyzing or burning small samples of materials at two decomposition temperatures, one flaming mode and one non-flaming mode. The

temperature and the oxygen concentration in the chamber are monitored

and kept within specified limits in order to prevent an additional significant contribution to the toxicological insult. An additional test at a specified temperature under non-flaming conditions may be used.

2.5.3 Lethality is the principal biological end-point obtained

from these experiments, and results are expressed as: (1) the LC,_q

calculated from the percent lethality which occurs during a 30 minute

exposure and a 14 day post-exposure observation period and, optionally,

(2) the percent lethality which occurs during a 10 minute exposure and

14 day post-exposure period which results from a specific concentration

of combustion products of 30 mg/2..

2 . 6 APPARATUS

2.6.1 Animal Exposure Chamber.

2.6. 1.1 A nominal two hundred liter animal exposure chamber

including a small combustion furnace, as shown schematically in figure 1,

shall be used.

8
2. 6. 1.2 The exposure chamber shall be made of 1.2 cm (0.5 inch)

•'lear polymethylmethacrylate with inside dimensions of 122 x 36 x 46 cm

(48 x 14 x 18 inches). Six animal ports are positioned, as shown in

figure 1, and are constructed of polymethylmethacrylate tubing 6.3 cm

r 2.5 inch) I.D. having a 0.3 cm (1/8 inch) wall thickness.

2. 6. 1.3 A blow-out panel should be provided in the top of the

exposure chamber on the right side away from the furnace to provide

pressure relief in case of an explosion (fig. 1).

2.6.2 Cup Furnace (Note 1).

2. 6. 2.1 The furnace must be capable of operating up to 800°C and

be controlled to + 10°C. The furnace is connected to the bottom of the

exposure chamber under the stainless steel plate (fig. 2) which contains

a cooling coil through which cold water is continuously run throughout

all experiments. Details of the furnace are shown in figure 3 (Note 2).

2. 6. 2. 2 A quartz beaker, 9 cm I.D. by 15 cm high, is inserted into

the furnace after the furnace is connected to the exposure chamber.

2. 6. 2.

3

For flaming combustion an electrically heated wire or other

electrical ignition source is used to ignite the products as they exit

from the furnace. The ignition coil is only used to insure ignition of

Note 1: For composite materials and some end use products with layered

construction where exposed surface area is a major factor, a radiant heating system including a load cell to measure sample

weight loss may have a number of advantages over the cup furnace. Such a radiant heating system is currently being explored

as an alternative combustion module. See section 2. 9. 2. 2.

Note 2: A furnace and controller meeting this requirement are commer- cially available from Thermcrait , Inc. , Winston Salem, N.C.

,

375-A-1183.* as model no. * *Certain commercial equipment, instruments, or materials are identified

in this paper in order to adequately specify the experimental procedure.

In no case does such identif ic-_ion imply recommendation or endorsement

by the Natioial Bureau of Standards, nor does it imply that the equipment or material identified is necessarily the best available for the

purpose.

9
the sample during animal exposure and is not used to establish the autoignition temperature of the material. This ignition system is at the

top of the quartz beaker.

2.6.3 Analytical Apparatus.

2.6. 3.1 Continuous measurements for oxygen (0^) , carbon dioxide

(CC^) and carbon monoxide (CO) are to be made and recorded. (See section

2.4.9 for reference to applicable procedures.) A non-dispersive infrared

(IR) technique is suggested for CO and CO^. The CO and CO

2 measurement

instrumentation should be capable of measuring a range of 0-10,000 ppm

with an accuracy of 200 ppm and 0-50,000 ppm with an accuracy of 700 ppm,

respectively. Oxygen measurements are to be made with an instrument

operating on the magnetic susceptibility or the electrolytic cell principle; it should be capable of measuring a range of 0-25% and an accuracy

of + 0.1% 0^. Alternatively, a gas chromatographic sampling technique

may be used, in which case measurements of 0^, CO^, and CO are to be made

every two minutes. The average oxygen level in the chamber shall not

fall below 16% during the exposure. Oxygen is to be supplied to the

chamber as needed to maintain the concentration between 16-21%.

2. 6. 3.

2

The continuous monitoring of 0^, CO

2 and CO is accomplished

by the removal of some of the products from the chamber. A flow of

approximately 0.5 liters/mi n is required for each instrument for analysis

of CO

2

, CO, and 0 ^. During a 30 minute exposure, this amounts to 15

liters per analyzer that is removed, analyzed, and pumped back into the

chamber. Oxygen should be added as needed depending on the degree of O

2 depletion. One must correct the total volume for this addition when

calculating the mass loading of combustion products (chamber volume plus

added volume at room temperature)

.

2. 6. 3.

3

The gas sampling port shall be at the animal nose level in

the geometric center of the exposure chamber, as shown in figure 2. The

gases for the CO, CO

2

, and O

2 analyses are returned to the left side of

10
the chamber above the furnace. The return tubes should be disconnected

during calibration of analytical instruments to prevent the inadvertent

accumulation of calibration gases (CO, CO^, etc.) in the animal chamber.

2.6.4 Temperature Measurements.

The environmental temperature of the chamber should be recorded

continuously during the 30 minute exposure. The temperature sensor must

be placed in the air at the level of the animals and within 5.0 cm (2 in.)

of one animal's nose. (A chromel-alumel thermocouple is recommended for

this measurement)

.

2.6.5 Aninal Restrainers.

Animal 'estrainers designed to permit head only exposures shall be

used. A detailed description of one type of animal restrainers meeting

this requirement is given in figure 4.

2.6.6 biological Measurements.

2. 6. 6.1 During the 30 minute exposure period, observations of the

animal behavior should be noted and recorded. Any unusual behavioral

activity should be recorded along with the time.

2. 6. 6.

2

The percent carboxyhemoglobin (COHb) is to be measured in

two of the six exposed animals. If the animals are cannulated, the

blood should be taken before the exposure (0 time, control blood) and

just before the end of the exposure (approximately 29 minutes). Cannulati<

must be done 24 hours prior to exposure according to the procedure of

Packham et al . (see section 2.4.7 for reference). If non-cannulated

animals are used to measure COHb, the blood must be taken within 5 minutes of death or the end of the 30 minute exposure. The blood may be

obtained via cardiac puncture, intraorbital venous puncture or from the

dorsal aorta. Any animals used to obtain blood must be sacrificed

following th ' exposure and not kept for the 14 day post-exposure period.

11
2.6.6. 3 Lethality, which include deaths during the 14 day postexposure period, is evaluated as a function of the mass loading to con- struct a concentration-response curve from which the LC,_q and slope of

the concentration-response curve are calculated. The LC,_q with the 95%

confidence limits and the slope of the concentration-response curve should

be obtained via an appropriate published statistical method, such as that

of Litchfield and Wilcoxon (Note 3) [see section 2.4.4 for reference].

2. 6. 6. 4 For materials that have an LC,_g of 2 mg/2, or greater,

lethality resulting from a 10 minute exposure to the decomposition

products of materials at a mass loading/chamber volume of 30 mg/ 2, may be

measured. This optional 10 minute test is to identify materials which

rapidly produce concentrations of combustion products that cause death

within the 10 minute exposure and a 14 day post-exposure period.

Note 3: To calculate a statistically valid LC,_g, at least three con- centrations producing responses between 0% and 100% must be

tested. To determine these three concentrations may require

more than three experiments. For some materials, the investigator may be unable to determine three concentrations producing

effects between 0 and 100%, i.e., a 0.5 mg/2, difference in

concentration changes the percent response from 0 to 100%. In

this case, the LC,-g may be estimated from the linear graph of

the percent lethality for each concentration for a given thermal

condition versus the concentration of the combustion products.

All deaths that occur during the exposure and 14 day postexposure period must be included in this estimate. The results

should indicate the concentrations used to estimate the LC^g.

Post-exposure deaths which occur seven or more days following

the exposure may be due to a pulmonary infection. If this is

suspected, pathological examination of lung tissues should be

performed on both exposed and unexposed animals to ascertain

whether or not the post-exposure deaths are a result of an infection in the animal colony and not the toxicological insult.

12
2 .

7

CALIBRATION

2.7.1 Instrumentation for the measurement of CO, CO^ and 0^ is to

be calibrated before each test using standard gas mixtures of a combination of CO, C0

2 and 0

? in nitrogen.

2.7.2 Instruments used for measurement of carboxyhemoglobin should

be calibrated according to manufacturer directions and checked daily.

2.8

ANIMAL CARE

2.8.1 Adult male rats weighing 225-325 grams that are 3-4 months of

age shall be used (Note 4). In all cases, normal steps shall be taken to

assure that healthy animals are used in testing. It is recommended that

1 rat in 10 be used as a control. Weight change during the 10 day preexposure period and 1

'4 day post-exposure period should be measured and

recorded. At the end of the 14 day post-exposure period, it is recom- mended that the control animal be sacrificed and a pathological inspection

of the pulmonary system be conducted.

2.8.2 Animals shall be maintained on ad libitum food and water

schedules and treated in accordance with Good Laboratory Practices

published in the Federal Register (see section 2.4.2 for reference).

Animals received from a supplier shall be housed at the testing laboratory for a minimum of 10 days before being used in testing.

2.9

TEST SPECIMEN

2.9.1 Sample Conditioning.

2. 9. 1.1 Material samples to be evaluated for toxicity should be

conditioned i n a constant humidity chamber maintained at 50% + 10%

relative humidity at a room temperature of 22 + 3°C for a period of

Note 4: Fischer 344 rats or equivalent are suggested.

13
48 hours prior to testing. The sample specimen is to be tested in one piece if possible.

2.9.2

Sample Size and Configuration.

2. 9. 2.1 The size of the test specimen for the initial test will

vary depending on the expected toxicity of its combustion products, but

will normally be about 5 grams. For example, 5 grams of material thermally degraded leads to a concentration of combustion products of 25 mg/v.

.

Sample sizes for subsequent tests will be selected, based on the results

of the initial test, to provide a range of mortalities sufficient to

construct a concentration-response curve.

2. 9. 2.

2

Test specimens shall be representative of the materials

from which they are taken. Therefore, only pure materials or composite

materials of a uniform structure, such as filled materials, can be studied.

(Assemblages of non-uniform structure such as carpets or layered wall

structures where the response of the material will depend on orientation

and the direction of the fire exposure can not be evaluated by the

present test.) Whenever possible, the test specimen should be a single

piece of the same thickness as the material being tested.

2.9. 2.

3

Paints, adhesrves, etc. shall be applied to glass, allowed

to dry and scraped off the glass before weighing and testing.

2.9. 2.4 Fabrics, thin films, and flexible cellular materials shall

be lightly rolled up and, if necessary, bound with a thin stainless steel

wire to maintain a size appropriate for the furnace diameter and depth.

14
2 . 10 TEST PROCEDURE

2.10.1 All tests should be conducted In a room or enclosed space

having an ambient temperature of 22 °C + 3° and relative humidity of 50% +

10% at the time of test.

CAUTION : Provisions must be made for removing combustion products

from the exposure chamber without contaminating the work space of the

test operators. The exposure chamber should be housed in a chemical hood.

2.10.2 Inside chamber wall surfaces should be cleaned when changing

the test material, or temperature of decomposition, or following test runs where toxicological] y significant combustion products are suspected

of accumulating as particulates, or as visual inspection may indicate.

2.10.3 Combustion Conditions

2.10.3.1 The toxicity of combustion products from the test materia]

is to be determined separately for two conditions: (a) 25°C below autoignition (non-flaming) and (b) 25°C above auto-ignition (flaming). An

extra, optional test at 440°C (non-flaming) may be used if one desires

to compare materials at a single temperature. (The 440°C is 25°C below

the average auto-ignition temperature of Douglas fir.) The maximum

temperature at which the material is to be tested is 800°C regardless of

whether it is flaming or non-flaming.

2.10.3.2 Since the auto-ignition temperature may be dependent on sample size, it is recommended that the sample size used to determine the

auto-ignition temperature be the maximum that one anticipates using for

toxicity tests since a large size may ignite at a lower temperature.

CAUTION: One should not exceed an 8 gram sample to reduce the risk

of creating an explosive mixture.

15
To determine the auto-ignition temperature, the temperature of the

furnace is set at 500°C and when this temperature is attained, the material

is introduced into the furnace. If auto-ignition does not occur, the

process is repeated at 50°C intervals until the auto-ignition temperature

is located. The auto-ignition temperature should be finally determined

within 25°C. If auto-ignition does occur at 500®C, the furnace temperature should be decreased in increments until the auto-ignition temperature

is bracketed within 25°C. The ignition system mentioned in paragraph

2. 6. 2. 3 should not be used for finding the auto-ignition temperature.

When the auto-ignition temperature of the material has been established,

the furnace temperature is decreased by 25°C for testing the non-flaming

condition (Note 5)

.

2.10.4 Test Procedure - 30 Minute Exposure.

2.10.4.1 Prior to experiments involving animal exposures, the

system should be checked out to determine that the analytical and com- bustion systems are all operating correctly.

2.10.4.2 To check the entire system, a standard material should

be run. This standard should be Douglas fir for which the LC,.q data

from 7 laboratories for the 30 minute exposure and 14 day post-exposure

observation period is shown in table 3. If the LC,_q results for the

non-flaming and flaming conditions fall within the 95% confidence limits

of the mean of these laboratories, the performance of the system will be

considered acceptable.

2.10.4.3 Each new material to be tested for toxicity should be

used in the system before animals are exposed. This check-out procedure

is to determine:

Note 5: Douglas fir has an auto-ignition temperature, as found by the

above procedure, of approximately 465°C. As the determination

of the auto-ignition temperature depends upon the apparatus

and procedure, the auto-ignition temperatures determined by

this procedure may differ from those measured according to

ASTM D 1929.

16
(1) the degree of oxygen depletion during combustion of the sample,

(2) that the average chamber temperature over the 30 minute exposure

period measured at the nose position of the animal does not

exceed 40°C (Note 6)

,

(3) that the proper conditions have been established for carrying

out either non-flaming or flaming combustion exclusively, and

(4) the estimated mass loading required to produce any deaths

(Note 7).

For the flaming test exposure two drops of ethanol can be added to the

sample and an electrically heated wire or electric spark used to

insure early ignition of the test material. Once these conditions have

been established, an experiment involving animals can be initiated.

2.10.4.4 The instruments for and CO measurements are zeroed

and a base line established during the checkout procedure. Oxygen con- centration is also recorded prior to initiation of the exposure.

2.10.4.5 Sample mass loss may be determined by weighing the charged

quartz beaker before and after an experiment.

2.10.4.6

The furnace is brought up to the desired temperature and

the system allowed to reach equilibrium 10 minutes before the start of

the experiment. During this warm-up period and the recording of preexposure data, the door of the exposure chamber is left open.

Note 6: The limitation of an average 30 minute temperature not exceeding

40°C is based on results from 12 materials in the NBS chamber.

Brief excursions to higher temperatures may occur during periods

of active flaming of the sample. At this time, the synergistic

or additive effects of temperature and toxicants are not known

for animals exposed head only in this system,.

Note 7: A CO dose (average CO concentration times 30 minutes) of approximately 100,000 ppm-min is a reasonable rule of thumb to use in

estimating the mass loading of a material that leads to lethality.

If other toxicants play a significant role in lethality, such as HCN from a nitrogen containing polymer, a 100,000 ppm-min dose

will be too high.

17
2.10.4.7 After these conditions are established, the animals are placed in their positions. To initiate the experiment, the weighed

sample is placed in the furnace and the door of the chamber is immediately

closed. Placement of the sample into the furnace designates the starting

time of the exposure. The animals are then exposed for 30 minutes.

2.10.4.8 If preliminary experiments show that the average temperature in the exposure chamber will exceed the specification in 2.10.4.3,

the electrical power to the furnace may be cut off when the sample is

completely degraded. The length of time required to degrade a sample

which produces CO can be determined by monitoring the increase of CO

concentration. For those materials that do not produce CO, another

degradation product can be analytically monitored. When the concentration

reaches a steady state for 2 minutes, the heater should be shut off.

2.10.4.9 Blood samples are obtained from two animals as rapidly as possible (within 5 minutes) at the end of the exposure (Note 8). The

pathological examination of any animals that die during the exposure or are sacrificed immediately after the termination of the exposure is

optional. If conducted, it should focus on the condition of the respiratory tract with visual observations recorded of soot deposits, pulmonary

edema, and hemorrhagic lungs.

2.10.4.10 Clinical examination of live animals following exposure

is optional. While still in the restrainer, the animal's eyes may be

examined for reflexes, redness, tearing, corneal opacity; the animal's

nose and mouth can be examined for any discharge, and respiratory

difficulties (gasping, wheezing, rapid or slow breathing) should be

Note 8: COHb values are a good guide for assessing the significance of

CO as the primary toxic agent. Values of COHb _> 75% generally

lead to lethality in some fraction of the animal population.

When deaths occur below 75% COHb, the presence of an additional

toxicant (s) is indicated.

18
noted. After removal of the animal from the restrainer, the investigator

may examine the animal’s exploratory behavior (does the animal explore

his surroundings and try to escape) , righting reflex (animal is placed on his back and the ability to right himself is scored as rapid, slow or non-existent) , and posture (animal is lifted from table by his tail and

placed back on table noting irregularities such as limp hind legs)

.

2.10.4.11 The animals are to be kept for a period of 14 days postexposure. Any deaths during this time period should be included in the

LC^q calculations. In addition, note and record any unusual behavior

during these days and daily animal weights.

2.10.5 Test Procedure - 10 Minute Exposure

2.10.5.1 The objective of this additional optional test is to

determine if materials with a statistically calculated LC<_q (30 min and

14 days) of greater than 2 mg/Jl rapidly produce concentrations of combustion products that cause death within a 10 minute exposure and a 14 day

post-exposure period when decomposed at a concentration of 30 mg/

i

l. Materials with an LC^ < 2 mg/S, are quite toxic and as a safety precaution should not be tested at 30 mg/£.

2.10.5.2 The procedure in 2.10.4.3 to 2.10.4.6 is repeated.

2.10.5.3 Two separate 10 minute exposures of animals at 30 mg/£ are performed using whichever condition (flaming or nonflaming) that

gives the lowest LC^ concentration. After the 10 minute exposure, the

animals are removed from the restrainers and lethality within the exposure

or during a 14 day post-exposure observation period is noted. If 50% or more of the animals die during the 10 minutes or 14 days following exposure, this material is considered to produce toxic concentrations of

combustion products rapidly.

2 . 11 REPORTING

2.11.1 Sample:

19
2.11.1.1

Product description and generic components.

2.11.1.2 Weight before and after test.

2.11.1.3 Temperature and humidity at time of test.

2.11.1.4 2.11.2 Determination of auto-ignition temperature.

Exposure Chamber.

2.11.2.1 Temperature at nose of rats, prior to and during test at

two minute intervals.

2.11.2.2 Measurements of the chamber concentration of CO, CO

2

, and

0^ continuously or at two minute intervals.

2.11.3 Average temperature of furnace during test.

2.11.4 Animals.

2.11.4.1 Strain of rat and identity of the commercial supplier if one is used.

2.11.4.2 Weight of each animal when received, prior to test,

following test, and during post-exposure period (weight to be determined

daily)

.

2.11.5 Observations made during and after exposure, for example,

observations on animal posture, righting reflex, exploratory behavior,

respiratory function (gasping, wheezing), grooming, eye and nasal

discharge.

2.11.6 For the 10 minute exposure test (if conducted), note

percentage of animals who died during test or within 14 days.

20
2.11.7 Concentration-response curves and LC,_q for combustion modes

of paragraph 2.10.3.1. This includes a concentration-response curve from which a statistically determined LC,_q value, 95% confidence limits

on the the slope, and 95% confidence limits on the slope are calculated.

2.11.8 COHb, at end of each exposure.

2.12 TEST METHOD SENSITIVITY AND LIMITATIONS

2.12.1

The effectiveness of the test method to determine the acute

toxicity of combustion products will depend on the overall reproducibility

and repeatability of the test method. A limited interlaboratory study of

the operability and reproducibility of the test method has been carried

out.

2.12.2 Seven laboratories evaluated the toxicity of the combustion

products of Douglas fir in the flaming and non-flaming modes. The resulting values and their 95% confidence limits for each laboratory are recorded in table 3. The mean value and 95% confidence limits for all

the laboratories are also given. For Douglas fir in the non-flaming

mode, the mean LC^q and 95% confidence limits were 22.8 (13.4-32.2)

mg/£. In the flaming mode, the mean value was 36.0 (21.1-50.8) mg/ 2.. The Douglas fir results in table 3 should be used as a guide against

which laboratories can check the operability of their experimental

system.

2.12.3 If a laboratory's LC,.q results for non-flaming and flaming

Douglas fir fall within the 95% confidence limits of the mean values for

Douglas fir calculated for the seven laboratories (table 3) , the performance of their experimental system should be considered acceptable.

2.12.4 The use of rats to measure the acute inhalation toxicity of

combustion products does not imply that a correlation has been established

between rats and humans for all toxicants. In spite of this limitation,

21
which is a limitation in all areas of toxicity testing, an evaluation of

toxic effects using animals is the best method available at this time.

2.12.5 The limitations of the cup furnace are:

(1) the size of the quartz beaker which fits into the furnace limits the

quantity of low density materials that can be tested,

(2) no means is provided for continuously measuring the mass loss of

material during the experiment,

(3) the effect of sample orientation cannot be assessed,

(4) assemblages of non-uniform structure can not be evaluated, and

(5) the thermal exposure conditions employed do not represent all

possible fire conditions.

2.13 SAFETY CONSIDERATIONS

2.13.1 The test procedure involves the generation of a potentially

flammable mixture and toxic products. To prevent the generation of an explosive mixture, no more than 8 grams of material should be degraded by

heat in the 200 l chamber. In the case of materials which contain inert

fillers and leave non- combustible residues, the sample size may be

increased if necessary as long as the weight of combustible fraction

charged to the furnace does not exceed 8 grams.

2.13.2 A pressure-relief panel should be provided in the chamber

cover opposite the furnace.

2.13.3 The chamber should be operated in a chemical hood (or

equivalent) to prevent the contamination of the worker space. Exhausting

of the chamber after a test should be carried out in the hood and not by

venting into the laboratory environment.

22
3o 0 COMBUSTION SYSTEM

3.1 INTRODUCTION

Generation of combustion products from a wide variety of materials

requires a heat source which is controllable over a wide range of temperatures. Ideally, the heat source would simulate the type of thermal energy

and temperature exposure that a material would experience in a real fire

situation. During the course of a fire, a material may undergo a non- flaming pyrolysis, a self-propagating smoldering decomposition, and/or a flaming combustion. In addition it may be subjected to a varying heat

flux. As no single laboratory test could possibly duplicate the infinite

number of real fire variations, which are due to both changes in heat

flux and available oxygen, only the following alternatives and issues

were explored: (1) combustion within the animal exposure chamber (static

system) or in a separate chamber (dynamic system), (2) radiant or convective heat, (3) preset exposure temperatures or ramped temperatures,

increasing at some fixed rate, (4) a single temperature for every material

or various temperatures depending upon the material, (5) flaming and/or

non-flaming conditions, (6) the amount of heat generated in the animal

exposure chamber by the furnace and (7) the decrease in oxygen concentration during the exposure. As this test is designed only to assess the

toxicity of the material’s combustion products, issues 6 and 7 are important to insure that the exposed animals do not experience undue heat

stress or oxygen deprivation.

3.2 STATIC VERSUS DYNAMIC COMBUSTION SYSTEM

In a static combustion system, the furnace is located such that all

the combustion products are generated in the animal exposure chamber

where they remain for the duration of the experiment. In a dynamic

system, the furnace is located some distance away from the animal exposure chamber and the combustion products are transferred via a pump or a blower. A completely dynamic system allows the products to flow through

the chamber and to escape. Examples of dynamic systems are the DIN

apparatus which has been described by Kimmerle [8] and the system of

Alarie and Anderson [9], 23
The decision to utilize a static rather than a dynamic combustion

system was based on the disadvantages of the larger sample size required

by a dynamic system and possible loss of toxicants during transfer. The

location of the furnace is shown in figure 2. However, it is important

to note that even in the chosen static system at NBS, a continuous

sample of the combustion products is transferred from the exposure

chamber at a rate of 2 liters per minute through the analytical equipment

and returned to the chamber. Water (and possibly some toxicants) and

particulates are removed via an ice trap and glass wool filter before

the gases are analyzed and returned to the exposure chamber. The

animals experience all the combustion products prior to the transfer, but

some loss will be experienced during the transfer to and from the analytical

equipment (Note 9) . One participant in the ILE used a semi-dynamic com- bustion system, i.e., the furnace was separated from the exposure chamber

(fig. 5). Also, in a series of large scale (room-size) smoldering fire

tests performed at NBS for comparison with the small-scale toxicity tests,

a modification of the semi-dynamic system was used. In this case, when

the gas concentration in the room reached a particular predetermined

level, the smoke was transferred via a pump from the room of origin to

the animal exposure chamber where it was contained for the duration of

the exposure. The transfer tubes were kept as short as possible—124 cm long by 10 cm wide. The details of this comparison of the small scale

tests with the large smoldering fire tests are to be published soon

(Smith, et al. , NBS report, in preparation).

3.3 RADIANT VERSUS CONVECTIVE HEAT

Preliminary experiments on two radiant furnaces were conducted at

NBS before the start of the ILE. This early work tested a radiant panel

furnace consisting of quartz-iodide lamps placed on top of the exposure

chamber with the radiation directed through a quartz window at the

Note 9: In the worst case, where all toxicants are removed in the ice

trap, the average concentration over the 30 minutes in the

exposure chamber would be reduced by 14%.

24
sample located within the chamber. At the full wattage rating of the

2 lamps, a heat flux of 5 watts/cm was measured at a distance of 4.5 cm below the quartz window by a radiometer. A disadvantage of this system

was that the quartz window accumulated soot which reduced the transfer of

heat.

The second radiant furnace was based on the ISO ignitability cone [10].

The furnace consisted of a truncated pyrex cone coated with a reflective

silver-plated layer and contained a resistance coil wrapped around the

inside surface (fig. 6). The cone, which was located on the floor of the

chamber above the cup furnace, produced unacceptable temperature levels

within the chamber.

Because of the poor results from the preliminary experiments with

radiant energy furnaces (Note 10) , a convective heat furnace similar to

the one designed and described by Potts and Lederer [11] was selected.

In this system, a quartz beaker with a thermocouple well fits snugly

into a stainless steel cup surrounded by ceramic and wrapped with nichrome

wire. This cup furnace is surrounded by fire brick and encased in galvanized steel sheet (fig. 3). The quartz beaker in which the sample is

degraded is heated to a predetermined temperature which is monitored by

an automatic temperature controller.

In the interlaboratory evaluation of the proposed test method, the

convective cup furnace was used by all the laboratories. However,

different sizes of furnaces and quartz cups were used. They ranged from

Note 10: During the course of these studies, a radiant furnace which fits

below the exposure chamber was developed by the Weyerhaeuser

Company. Preliminary experiments with this furnace at NBS and

two other laboratories indicate that this furnace location may

prevent overheating of the chamber. The NBS work on this system

will be published as an NBSIR (Packham et^ al. , NBS report in

preparation)

.

25
79 m£ to 954 tn£ (table 4) . Most of the laboratories used a cup of approximately 300 m£ ; however, NBS also tested a cup furnace with a capacity

approximately three times greater (954 mil) . Good reproducibility of the

Douglas fir toxicological results across laboratories and the repeatability of these results by NBS using two different size furnaces (table 3)

indicates that the exact size of the cup furnace is not critical. The

larger size, however, is recommended as it can accommodate larger mass loadings of low density materials.

The decision on whether to replace the cup furnace with the radiant

furnace or some other combustion module will require additional study.

NBS plans to continue research on this issue, but in the present test

method recommends the cup furnace because of the greater amount of information and data already obtained on this system from the seven laboratories

that participated in the ILE.

3.4 PRESET EXPOSURE TEMPERATURES OR RAMPED TEMPERATURES

In a real fire situation, a material may experience slow or rapid

increases in temperature until it ignites in flames, or it may be exposed

to temperatures which cause a non-flaming pyrolytic decomposition. Both

of these conditions can be approximated in a small-scale test. A third

situation, self-propagating smoldering, is not easily simulated under

small-scale laboratory conditions. The first scenario can be simulated

by a ramped combustion system like that designed by Alarie and Anderson

[9] in which a temperature controller is programmed to increase the

temperature of the furnace at 20°C per minute and the material bursts into

flames at its auto-ignition point. Problems associated with a ramped

system are (1) the time necessary to reach the temperature needed to

decompose the materials and produce the toxicants, (2) a realistic rate

of temperature increase must be chosen, and (3) toxicants from both non- flaming and flaming combustion are combined.

Non-flaming pyrolysis can be approximated by the exposure of a material to a cup furnace heated to a predetermined temperature. The

test sample undergoes a very rapid rise of temperature until it

26
equilibrates with the furnace temperature. In other words, the material

experiences a very rapid ramped temperature, but, below the auto-ignition

point, stabilizes at the preset temperature, thus permitting the separate

investigation of non-flaming pyrolysis. Flaming combustion can be investigated in the same manner, but, in this case, the furnace is fixed at a temperature above that of the auto-ignition temperature of the material.

The advantage of this rapid temperature rise is that the combustion

products are produced rapidly and the animals are exposed to the highest

possible concentration of toxicants for a single loading for the greatest

length of time. As the total exposure is relatively short—30 minutes

maximum exposure to the toxicants during that time period becomes important.

Thus the decision was made to use preset rather than ramped exposure

temperatures.

3.5 ONE TEMPERATURE OR DIFFERENT TEMPERATURES FOR ALL MATERIALS

Good experimental practice prescribes keeping as many variables con- stant as possible. Therefore, the inclination is to examine all materials

at one temperature or perhaps at a set number of constant temperatures.

Toxicologists prefer to examine the effects of materials under the potentially most toxic conditions with the assumption that knowledge of the

worst case will prevent false negatives, i.e., a material or product that

appears safe, even though, under some untested conditions, it may be

extremely toxic.

In real fires, a material is subjected to a large number of exposure

conditions and the problem is which temperature (s) should be selected for

examination in the test method. Examination of all materials at one temperature or even a number of prescribed temperatures does not insure

the avoidance of false negatives. It is therefore imperative that the

temperature which produces the most toxic combustion products, both in

quantity and in intensity, be chosen for evaluation.

Prior research indicated that the higher the temperature the greater

the decomposition of the material, with the most decomposition in the

27
non-flaming mode occurring close to the auto-ignition temperature [11].

Above the auto-ignition temperature, the higher the temperature (under

good ventilation conditions), the more complete the combustion, where

complete combustion means total conversion to CO^ and H^O. Therefore,

the greatest quantity of, and most toxic, combustion products in the non- flaming mode are generated just below the auto-ignition temperature of a material. Research performed during the ILE supported this hypothesis.

One laboratory examined modacrylic at many temperatures (table 5), and

showed that as the temperature approached the auto-ignition point, the

combustion products became more toxic as defined by a lower LC,_q value

(for a discussion of LC,_q values, see section 6.3.3).

Likewise, the greatest quantity of, and most toxic, combustion products in the flaming mode should be generated just above the auto-ignition

temperature, since higher temperatures would lead to more complete combustion. However, the effect of furnace temperature is overshadowed by the

flame temperature and little difference has been seen in toxic effects.

Therefore, the test method requires the examination of materials

25°C above and below their auto-ignition temperature. If a material is

assessed under these temperature conditions and shown not to produce

highly or unusually toxic combustion products, it is assumed that other

thermal conditions will produce less toxic effects.

3.6 FLAMING AND NON-FLAMING CONDITIONS

3.6.1 Need for Both Flaming and Non-Flaming Conditions. The proposed test method examined by the ILE participants required the

evaluation of materials at one flaming temperature—25°C above the

auto-ignition temperature—and two non-flaming temperatures—25 °C below

the auto-ignition temperature and at 440°C, the temperature at which

Douglas fir (the reference material) is evaluated in the non-flaming

mode. 440°C was not required if the material's auto-ignition point was within 50°C of 440°C. The 440°C was required initially to satisfy those

who believe all materials should be evaluated at the same temperature.

The issue is whether all thiee exposure temperatures are necessary.

28
Results from the ILE showed that some materials were more toxic in the

flaming mode and others were more toxic in the non-flaming mode. All

laboratories found acrylonitrile butadiene styrene (ABS), modacrylic (MOD),

polystyrene (PSTY), poly (vinyl chloride) (PVC) and rigid polyurethane (RPU)

more toxic in the flaming mode. Most laboratories found Douglas fir

(DFIR), flexible polyurethane (FPU), polyphensylsulfone (PPS) , polytetraf luoroethylene (PTFE) , PVC with zinc ferrocyanide (PVCZ) , red oak

(REDO), and wool more toxic in the non-flaming mode (see section 6.3.3).

One disagreement was noted—one laboratory found Douglas fir more toxic

in the flaming mode. However, the flaming and non-flaming LC,_q (for a 30 minute exposure and 14 day post-exposure period) values were close

and fell within the 95% confidence limits of each other.

The above results demonstrate that it is necessary to test each

material under both flaming and non-flaming conditions as it will not be

clear at the outset which mode produces the more toxic conditions. In no case did the 440°C pyrolysis temperature cause a greater degree of

toxicity than the most toxic condition (see section 6. 3.2.2 and 6.3.3).

As examination of the concentration-response curves at 440°C does not

add toxicological information necessary to the assessment of any of the

ILE materials and since requirement of this additional temperature

significantly increases the expense and time required for the test, NBS

decided to make examination at the 440°C temperature optional.

3.6.2 Determination of Auto-Ignition Temperature. The test method

requires that the auto-ignition temperature of a given material be

determined experimentally before the material is evaluated toxicologically

.

One problem that became apparent during the determination of the autoignition point was the importance of sample size. Initially, a rather

small sample was used to find the temperature of auto-ignition. Later,

during the actual toxicological testing, larger samples were decomposed

and on some occasions, the larger samples underwent an exothermic reaction

generating enough heat that the furnace temperature rose above the set

29
temperature and eventually the material auto-ignited. When this occurred,

the auto-ignition and non-flaming temperatures were lowered. Therefore,

after determination of the auto-ignition temperature, it is advisable to

test a larger sample size (the size determined by the predicted amount

that will be decomposed during the tests) at the proposed non-flaming

temperature to insure that inadvertent flaming does not occur.

Composite materials pose additional problems with regard to determination of their auto-ignition temperatures which may reflect that

component with the lowest ignition point. The non-flaming temperature

may then be close to the most toxic condition for that portion of the

composite material but may be far enough away from the auto-ignition

temperatures of the other components of the composite that those portions

decompose less. Therefore, a limitation of this combustion system with

regard to composite materials is that the non-flaming toxicological

assessment may reflect to a greater degree the component of the composite

with the lowest temperature of ignition. The components should not be

tested separately as the separate constituents may not exhibit the

potential toxicological interaction of the totality, i.e., it is possible

that the component parts of the composite material will produce combustion

products that act in an additive, synergistic, or antagonistic manner. As was stated earlier, further work on the radiant combustion system may

provide a more suitable method for the evaluation of composite structures,

such as carpets or layered wall panels.

3.7 SAMPLE PREPARATION

3.7.1 Single or Multiple Pieces. The test method recommends that

the sample specimen be tested in one piece if possible (section 2. 9. 1.1).

Materials that were pellets, resins, or powders obviously were tested in

that form. NBS tested Douglas fir in one piece and in several pieces.

Results showed more CO was generated from two pieces than one piece at

the same mass loading of 20 mg/£; however, the toxicity results including

time-to-incapacitation were the same (table 6). Three pieces equaling

30
30 mg/£ produced the same amount of CO as one piece of the same weight.

Toxicological data was the same in both cases. Four pieces of Douglas

fir equal to 40 mg/£ produced about the same CO as the 30 mg/£. loading

and may be indicative of overloading the cup furnace. However, four

pieces produced more deaths during exposure and a slightly shorter mean

time to incapacitation. These results, although limited, indicated that

an increase in the number of pieces from one to four did not produce a significantly different picture either analytically or toxicologically

.

The decision to use a single piece, if possible, was again based on the

perception that materials should be examined in a condition as close as possible to that found in normal use.

3.7.2 Mass Loaded or Mass Consumed. Material of a known mass is

placed in the cup furnace. In many cases, a residue remains after the

experiment. Should the toxicological findings be based on the amount of

material initially placed in the cup furnace or the amount of material

that was actually thermally decomposed? Combustion products generated

during thermal degradation are diluted with the chamber atmosphere and

the amount inhaled by the animals depends upon their respiratory rate

and depth of breathing. This test method does not allow the calculation

of the actual concentration of combustion products which each animal

inhales. The concentration of combustion products in the exposure

chamber can be expressed as either the mass of material loaded into the

furnace (grams of material divided by the volume of the exposure chamber)

or the mass consumed during the exposure (grams of material consumed

divided by the volume of the exposure chamber)

.

When estimating the fire risk associated with the use of a material,

the total mass of the material present is usually considered. It seems appropriate to base the test results on the total mass of the sample

charged to the furnace. This simplifies the procedure and avoids ambiguities that might result since the weight loss from the sample may depend

on furnace temperature. Therefore, the test method specifies that the

concentration of material is defined as the amount of material placed

into the furnace (mass loaded) divided by the exposure chamber volume.

31
3.8 PRESSURE-RELIEF PANEL

The generation of combustion products in a static, air-tight system

produces an increase in pressure in the exposure chamber and has the

potential of causing an explosion. The members of the ILE did not

experience any explosions with any of the test materials. However, one member of the ad hoc working group with a different test system did

experience an explosion in his laboratory. As a safety precaution,

therefore, it is important to build a pressure-relief panel into the

exposure chamber. At NBS, this panel was a circle of 8.9 cm cut into

the right side of the chamber cover. There are many acceptable ways of

covering the opening so as to provide the necessary pressure relief.

3.9 SUMMARY OF COMBUSTION SYSTEM

3.9.1 Decisions. The combustion system in the test method described

in section 2 incorporates the results of many decisions based on both

experimental evidence and available information. It is not a perfect

system and will require future research to resolve some of the still

outstanding issues. Briefly, the following decisions were made in

arriving at the combustion system used in the current test method:

(1) the combustion system should be a static system rather than a dynamic

one,

(2) the heating system should be convective rather than radiant,

(3) exposure temperatures should be preset not ramped,

(4) the material should dictate the temperature chosen for decomposition,

(5) both flaming and non-flaming conditions, 25°C above and below autoignition temperature, respectively, are required,

(6) the heat and depletion of oxygen during the exposure should not cause additional stress to the animals (see sections 4.3 and 5.3),

(7) materials should be examined in a state as close to their normal use as possible, i.e., single pieces, and

(8) the assessment of materials should be based on the mass loaded into

the furnace, not the mass consumed.

32
3.9.2 Modifications. As a result of the ILE and subsequent tests

at NBS, the combustion system described in the test method has been

modified from that originally proposed [7, appendix A] in the following

ways: (1) a larger cup furnace, approximately 1000 mi instead of 300 m2,

is now recommended, (2) the examination of materials at 440°C is now

optional and (3) the chamber design has been modified to provide for

pressure relief.

3.9.3 Future Studies on the Combustion System. Additional studies

are needed to resolve the difficulties experienced in handling composite

materials. The radiant furnace may be more suitable for evaluating com- posites, but more research is required on the radiant furnace before a decision can be made as to whether it should replace the cup furnace or be considered an alternate combustion system.

4.0

ANIMAL EXPOSURE SYSTEM

4.1

CRITERIA FOR AN EXPOSURE SYSTEM

Many factors have to be considered in the design of an animal

exposure system. A review by MacFarland on respiratory toxicology

explored in detail the advantages and disadvantages of various exposure

systems [12], Many decisions made during the development of this test

method are based on MacFarland* s review. The options and issues examined

were (1) whole body exposure of the animals or head-only exposure, (2)

static exposure versus dynamic exposure, (3) size of chamber, (4) shape,

(5) construction material and (6) exposure duration.

4.2

WHOLE BODY VERSUS HEAD-ONLY EXPOSURE OF THE ANIMALS

Although \7hole body exposure is the more common approach in most

inhalation toxicological studies, it is considered less advantageous in

the study of combustion products for the following reasons: (1) considerable heat may be produced during the thermal decomposition of materials

and the potential for heat stress of the animal is far greater in whole

body exposure than in a head-only exposure mode, (2) smoke obscuration

33
of the animals contained within the chamber prevents visual observation

of biological endpoints such as incapacitation or death, (3) inaccessibility of the animals exposed via whole body prevents monitoring of

physiological parameters, such as incapacitation, respiratory rate, EKG,

EEG, body temperature, if examination of these functions is desired, (4)

blood samples may be taken during the exposure from cannulated animals in

the head-only mode or, if not cannulated, animals may be removed rather

easily for blood sampling at any time during the exposure with little

disturbance to the gaseous atmosphere of the chamber, (5) thermal decomposition of materials produces a large amount of soot and particulates

which may be deposited on the fur of the animals exposed via whole body

and could be a source of additional toxicants if subsequently ingested

during preening.

A disadvantage of the head-only exposure is the necessity of using

a restrainer to hold the animals (fig. 7). In addition to the stress

that the animals experience being placed into the restrainer, the normal

activity of the animals is also restricted. This restriction can affect

the animals' respiratory rate and thus the amount of toxic products that

the animals inhale, i.e., an animal that is free to exercise will have a greater respiratory rate than an animal prevented from movement.

4.3 STATIC EXPOSURE VERSUS DYNAMIC EXPOSURE

The description of both static and dynamic combustion systems and

the reasons for preferring a static system in the NBS toxicity test

method are explained in section 3.2 of this report. However, a static

system produces some additional constraints that must be considered in

the examination of combustion product toxicity in exposed animals. Both

the combustion process and the exposed animals consume 0^ and produce

CO^ (the latter is true for the combustion of most materials, although

not all) . Water vapor is also produced by both combustion and the

animals, and thus the relative humidity in the chamber may increase

during the static exposure. The amount of CO^ produced by six animals

exposed in a bead-only mode for 30 minutes under control static conditions

34
(no heat, no material decomposition) was 2900 ppm. It was not possible

to estimate the CO^ produced by the combustion of a material by subtracting the concentration of CC^ produced under control conditions because

some toxic atmospheres will change the respiratory rates of the animals.

Thus the rate of CO^ generation depends upon the material's

decomposition products and how these products affect the production of

CO^ by the animals. The same considerations are true for 0

^ depletion.

These changes in and CO^, which are related to the animals' respiratory

rates, cannot be separately analyzed and the total gaseous products have

to be analyzed when determining the toxic atmospheres. (Actual results

on CC>2 production and depletion are discussed in section 5.0 of this

report). However, by limiting the duration of the exposure to no more

than 30-60 minutes and by making the size of the exposure chamber as large as possible (see section 4.4.1), the animal contribution is minimized. For example, 8 grams of Douglas fir in the flaming mode produces

about 10 times the amount of CO^ produced by the 6 rats in 30 minutes.

The distribution of the decomposition products throughout the static

system was another factor that was investigated thoroughly. Both analytical measurements on CO, CO^, hydrogen chloride (HC£) , and hydrogen cyanide

(HCN) in various locations of the exposure chamber at different times and

a statistical analysis to determine if the order of incapacitation of the

animals was related to their location were examined to evaluate the mixing

characteristics of the exposure system. These results, which are published

in an NB3 report [7], demonstrated uniform distribution of the gaseous

combustion products.

A static exposure system also retards the dissipation of heat

generated by the furnace during the thermal decomposition of materials.

As the test method is des >gned to assess the "chemical" toxicity of

combustion products, the ;emperature of the chamber was monitored to

assure that the animals d d not have to contend with the additional

physiological problem of heat stress. Following a recommendation of the

35
NAS study [5], the originally proposed test method specified that the

chamber temperature should not exceed 35°C for any time period during

the 30 minute exposure [7, appendix A], NBS measured the temperature at

the center of the chamber and at animal positions 1, 3, and 6. Both

average temperatures over the 30 minute experiment and the maximum

temperatures were recorded. Temperatures measured close to the heads of

the animals were usually lower than that measured in the center of the

exposure chamber. NBS data on the maximum temperatures recorded at the

animal positions for each material regardless of mass loaded in the

furnace are shown in figure 8. In the flaming mode, these maximum

temperatures rose above 35°C for all materials. In the non-flaming

mode, the maximum temperature exceeded 35°C for Douglas fir (41°C)

,

modacrylic (38°C), polyphenylsulfone (39°C) , polystyrene (36°C), PVC with

zinc ferrocyanide (40°C) and wool (36°C). The only material decomposed

at 440°C at NBS that caused a chamber temperature greater than 35°C was wool and in this case, the maximum temperature recorded was 36°C.

The maximum chamber temperatures for all the laboratories participating in the ILE are shown in table 7. The variation in chamber temperatures between laboratories is a reflection of the flaming conditions, i.e.,

the flame temperature, the duration of flaming, the packing of the material

into the cup furnace, the available oxygen, and the mass of material loaded

into the furnace. This table shows the maximum temperature regardless

of the weight of material burned.

The material which produced the greatest increase in chamber temperature was wool decomposed in the flaming mode. NBS found a 41 mg/£

concentration caused an initial rise to 109°C during the first minute

(fig. 9). Five minutes after initiation of the test, flaming had subsided

and the chamber temperature had decreased to 38°C and reached 33°C by 30

minutes. Three animals died during this exposure. However, a 22 mg/£

concentration of wool also decomposed in the flaming mode showed a very

similar temperature profile reaching 100 °C in one minute and caused no deaths within the exposure (fig. 9). Although more study is needed to

determine the synergistic effects of temperature and combustion products,

36
it appears in this case that the resultant deaths are more likely due to

the increased loading and not the increased temperature. For comparison

purposes, the chamber temperature profile for Douglas fir decomposed in

the flaming mode at a concentration of 52.2 mg/£ is also shown in figure

9. In this case, an initial rise to 42°C occurred in 4 minutes and was followed by a gradual decrease to 32°C by the end of the experiment.

Based on the experimental results from NBS and the other laboratories,

the average chamber temperature for the 30 minute exposure at the nose

position of the animals is not to exceed 40°C. As only the heads and not

the whole body of the animals are exposed, it is not believed that these

temperatures add a significant thermal stress to the animals. However,

more experiments are necessary to determine the additive or synergistic

effects of increasing the heat in the chamber in combination with sublethal concentrations of toxic combustion products.

4.4 EXPOSURE CHAMBER DESIGN

4.4.1 Size of Chamber. In a real fire situation, the occupants

are not expected to remove a significant amount of toxicants or 0^ from

the atmosphere nor are they expected to contribute a significant amount

of CO^. In a static exposure system, the size of the chamber must be

sufficiently large for the animal contribution to or depletion from the

atmosphere to be also insignificant. According to the review by

MacFarland, if the animals do not occupy more than 5% of the chamber

volume their contribution is not significant [12]. A 300 gram rat

occupies approximately 0.3 liters, therefore, to hold 6 rats, the chamber

must have a minimum volume of 36 liters. However, the larger the chamber,

the less the possibility that the animals will significantly affect the

atmospheric concentrations of thermal decomposition products and modify

the normal 0^ and CO^ concentrations. Also a larger chamber reduces the

possibility of large increase in temperature. Therefore, a chamber size

of approximately 200 liters -/as proposed for the test method.

37
4.4.2 Shape of Chamber. Uniform distribution of the combustion

products depends upon the shape of the chamber. The NBS toxicity test

method exposure chamber is a rectangular box with inside dimensions of

119.4 cm long by 35.6 cm wide by 45,7 cm high (figs. 1 and 2). The cup

furnace is located below the left side and six portholes are positioned

across the front to hold the animals. This chamber provides good mixing

characteristics (see section 4.3). In addition, the chamber allows easy

access to the animals and fits in a chemical exhaust hood, a necessary

safety feature for testing toxic combustion products.

4.4.3 Construction Material. The chamber is constructed of 1.25 cm polymethylmethacrylate sheet. This material permits good visibility into

the chamber and is resistant to the variety of chemical combustion

products generated and the heat produced in this series of experiments.

The adsorption of hydrogen chloride by the polymethylmethacrylate was tested and presented no problems [7].

Periodic cleaning of the exposure chamber is required to prevent cross contamination of toxicants and to reduce carbonaceous material from

acting as a scavenger for various reactive chemical species. The chamber

was always cleaned between experiments on different materials as well as between different temperature modes. Ethanol applied with disposable

towels proved to be the best method for removing the various decomposition

products that had deposited on the inside surface of the chamber.

The only means of access to the NBS exposure chamber is to remove its top. This may not be the best design as it makes the chamber difficult to clean. A chamber designed with several removable sections would

facilitate cleaning. However, more removable sections increases the

possibility of leakage of the gaseous products of the chamber's atmosphere.

The quartz sample beaker which fits into the furnace was washed and

the remaining products removed by a propane torch after each experiment.

It is advantageous to have several quartz beakers on hand.

38
4.5 EXPOSURE DURATION

In most experiments, the animals are exposed to the combustion

atmosphere for 30 minutes. This time was chosen as representative of a reasonable time for an occupant to escape a burning building or to be

rescued. In addition, 30-60 minutes is about the maximum time that the

animals could remain in a static exposure system without significantly

influencing the atmosphere (depletion of 0^, increase of CO^) as described

in section 4.3 of this report.

Additional optional exposures of only 10 minutes in length are also

described. These shorter experiments in which the animals are exposed to

relatively high concentrations (30 mg/Ji) were designed to distinguish

materials that rapidly produce effective concentrations of toxicants.

After both the 10 minute tests and the 30 minute tests, the animals are kept for a 14 day post-exposure observation period. The rationale for

these tests will be further explained in section 6.4.

At NBS, the exposure began with the dropping of the sample into the

preheated cup furnace and closing the door of the chamber. The exposure

ended with very rapid exhausting of the chamber atmosphere.

4.6 SUMMARY OF ANIMAL EXPOSURE SYSTEM

The following decisions were made in arriving at the animal exposure

system used in the current test method:

(1) the animals should be exposed head only, not whole body,

(2) a static animal exposure system rather than a dynamic exposure

system should be used,

*(3) the average chamber temperature for the 30 minute exposure at the

nose position of the animals should not exceed 40°C,

* New procedures or procedures that have been modified from those proposed in the original test method [7, Appendix A].

39
(4) the exposure chamber should be a polymethylmethacrylate rectangular

box of approximately 200 liters,

(5) the animals are exposed for 30 minutes to the combustion atmosphere

in most experiments, and

*(6) in some cases, an optional animal exposure of only 10 minutes to a concentration of 30 mg/Ji may be used.

5.0 CHEMICAL MEASUREMENTS

5.1 NEED

Thermal degradation can produce hundreds of gaseous compounds,

including for example, car'jon monoxide, carbon dioxide, oxides of nitrogen

and sulfur, hydrogen cyanide, hydrogen chloride, simple hydrocarbons,

oxygenated organic product.; (aldehydes, ketones and acids) and nitrogencontaining organic product;; (amines and nitriles). A detailed analysis

of these products requires sophisticated analytical equipment, e.g., a gas chromatograph-mass spectrometer (GC-MS) in conjunction with an on-line

data reduction system. Such an analytical scheme is costly and impractical

for a routine test method. Therefore, the test method is limited to the

identification and quantification of selected gaseous products of recognized toxicological importance.

According to a review of toxicological and fire accident data [3],

the three most important combustion products are CO, CO

2

, and HCN. CO

and CO

2 are produced during most combustion processes, since all organic

compounds contain carbon. Materials that contain nitrogen are potential

producers of HCN.

CO is an important toxicant because of its ability to combine with

hemoglobin and displace oxygen in the blood. The main physiological

effect of CO

2

at concentrations generated in this study is to increase

* New procedures or procedures that have been modified from those proposed in the original test method [7, Appendix A],

40
respiration of the animals. Furthermore, production of CO^ is an indication of completeness of the combustion process and the relationship

between CC^/CO ratios and 0^ concentration can be used to illustrate

changes in the combustion process, if desired. HCN has a relatively

high toxicity as it acts by inhibiting cellular respiration. Even though

the increased use of polymeric materials containing nitrogen has focused

attention on the potential involvement of HCN in fire environments,

measurement of HCN during the proposed test method is optional. This is

mainly because of the lack of a suitable automated technique for measuring HCN in fire atmospheres and in biological samples. Three laboratories

in the ILE measured chamber concentrations of HCN when nitrogen-containing

materials were degraded. Recently, a guide for measuring various com- bustion products has been published which can serve as a useful reference

for the selection of appropriate measurement techniques for gaseous

toxicants, including inorganic halides, HCN, oxides of sulfur and

nitrogen, and aldehydes [13].

5 . 2 INSTRUMENTATION

5.2.1 Sampling System at NBS. The system used by NBS for sampling

combustion products from the exposure chamber was designed to obtain a representative sample, maximize recovery, and to avoid introduction of

errors due to sampling techniques.

Figure 10 is a schematic of the continuous sampling system chosen for

the determination of the time dependence of CO, CO^, and 0

^ concentrations.

At NBS, the gaseous products are pumped at a rate of 2S,/min through the

main sampling line. Approximately 0.5Jt/min pass through each instrument

and are returned to the chamber to avoid alteration of the combustion

product concentration in the exposure chamber. Any excess gaseous

products which do not pass through the instruments are returned to the

box via the pressure relief valve (PRV) in the pump (fig. 10). Sample

transfer flow rates were measured using rotameters.

41
To collect a representative sample, a sampling probe is introduced

through the top, between the third and fourth animal position, about 15 cm into the chamber. Pretreatment of the gas sample is done by a glass wool

filter and an ice trap for the removal of particulates and water vapor to

avoid their interference with analytical measurements. Invariably, the

removal of particulate matter was found to be necessary as the smoke

particles caused malfunctioning of the sampling pump and deposits in the

analytical apparatus.

The sample transfer lines are constructed of non-permeable polyethylene tubing. PTFE tubing is used in some interconnections of

instruments. These materials are usable with essentially all types of

combustion products. A small stainless steel diaphragm type compressor

pump is used.

To assure the retention of sample integrity by minimizing adsorption

and condensation on surface s, it is usually recommended that filters and

transfer lines be heated [13]. However, since an ice trap is inserted

into the sampling system to remove moisture, heating of sample lines is

not considered necessary. During a 30 minute exposure period a total of

605- (about one-third of the total volume) passes through the sampling

system at NBS. Some condensation of combustion products occurs in the

ice trap and cannot be avoided (see Note 9, page 24). Lowering of the

trap temperature, e.g., with dry ice, was found to decrease the overall

toxicity of the combustion atmosphere, presumably by more effective

condensation of combustion products, and is therefore not recommended.

On occasion, the investigator may wish to measure hydrogen cyanide

concentrations in the chamber atmosphere. For determination of time

dependence of HCN concentration in NBS tests, a batch sampling technique

is used for immediate analysis by gas chromatography. The combustion

atmosphere is sampled with a gas-tight syringe through a septum in the

front wall of the chamber at the level of animal noses. The sampling

frequency depends on the retention time of HCN and the chromatographic

profile of the nitrogen-containing products which are determined for

each material tested. Sami ling times are selected so that the eluting

42
HCN peak does not encounter any interference. The volume of gases

removed by the syringe sampling technique (100 each time) is insignificant when compared to the total volume.

5.2.2 Carbon Monoxide and Carbon Dioxide. Commercial nondispersive infrared analyzers based on the Luft cell principle are employed

for continuous monitoring of CO and CO^ in the combustion mixture. The

analyzers are specific for single gases and CO^ concentrations up to

200,000 ppm do not interfere with the CO measurements. In most cases,

the CO concentration is low in comparison to CO^ and its interference

with CO^ measurements need not be considered. The cold trap minimizes

any likely interference by water vapor.

To cover the concentration ranges encountered in the exposure over the loading ranges studied for all the materials, it is necessary to

outfit the analyzers with cells of several lengths. During the test

method development, the following ranges were needed:

CO

0-1000 ppm

0-5000

0- 10,000

0-50,000

0-5000 ppm

0-25,000

0-50,000

0- 200,000

To assure the accuracy of measurements, calibration of the infrared

instrumentation is carried out before each experiment using appropriate

certified gas mixtures (CO and CO^ in nitrogen) available commercially.

Since the exhaust from the analyzers is normally returned to the exposure

chamber, it is necessary that the line be disconnected from the chamber

during calibration, e.g., by using a 3-way valve, to avoid buildup of

calibration gases in the exposure chamber.

5.2.3 Oxygen. The continuous monitoring of 0^ in the exposure

chamber was carried out using an oxygen cell in which O

2 diffused through

a membrane into KCfi, electrolyte where an electrochemical reaction between

43
two electrodes took place. The strength of the current generated was directly related to the amount of 0^ introduced. The cell was calibrated

with ambient air assuming 20.9% 0^ content.

5.2.4 Hydrogen Cyanide. The analysis of HCN in the combustion

atmosphere was determined by a gas chromatographic method utilizing an alkali flame (or thermionic) detector in conjunction with Porapak Q

column at 110°C. The details of development of the technique have been

described by Paabo et al. [14]. Under the experimental conditions the

retention time for HCN was about 2 minutes, allowing HCN samples to be

taken every 2-5 minutes. The thermionic detector was tuned with m and

air (flow rates of 3 and 100 m£/min, respectively), so that no interference

by low molecular weight hydrocarbon compounds would be observed. Calibration of the gas chromatographic system was performed with certified

reference gas of HCN in nitrogen, available commercially. The concentration of HCN gas mixtures in new tanks was verified by titration with

standard AgNO^ solutions. Since the HCN reference gas is somewhat

unstable, the concentration of HCN gas mixtures in old tanks was checked

periodically by titration and gas chromatographic techniques. All

cylinders of HCN should be used and stored in a chemical hood as a safety

precaution.

5.3 NBS RESULTS

The following information is presented to illustrate how analytical

measurements can provide additional information on the nature of the

toxic effect. The test method requires that CO, CO^, and 0^ be measured

during animal exposures. During the development of the test method,

analyses were carried out for all materials except for polytetraf louroethylene (because of the possibility of fluorides damaging the instrumentation). For the six nitrogen-containing materials, ABS , flexible

polyurethane, modacrylic, poly (vinyl chloride) with zinc ferrocyanide

,

rigid polyurethane, and wool, HCN measurements also were made during

animal exposures.

44
The data obtained during animal exposures as well as data obtained

during analytical runs are included in the following summary. As noted

in section 3.3, NBS used two furnaces of different sizes designated as furnace a (small - 300 m2 cup) and furnace b (large - 954 m2 cup). The

auto-ignition temperatures found by NBS are listed in table 25.

CO, CO^, and HCN are reported as the mean and standard deviation of

the ratios of the concentrations (ppm) of the gas (averaged over the 30

minute exposure) to the mass loading/chamber volume (mg/2) for each test

of a material. These results are shown in tables 8, 9, and 10, respectively. Data for 0^ are reported as minimum average percentages (the

experiment that produced the lowest average oxygen concentration) in

table 11. The average concentrations of a species for an experiment was obtained by integrating the area under the instrument response curve and

dividing by the duration of the experiment, 30 minutes. Graphic representations and least squares linear regression analyses of the generation

of CO and HCN versus mass loading in the non-flaming and flaming modes

are shown in figures 11, 12, 13, and 14.

In the case of Douglas fir, the production of CO was found not to

be linearly proportional to mass loading over the total range of concen- trations studied. The upper limit of linearity was 30 mg /2 in the non- flaming mode and 50 mg/2, in the flaming mode. This apparent over- loading of the cup is illustrated graphically in figures 15 and 16. The

CO concentrations for Douglas fir above 30 mg/2, (non-flaming) and 50 mg/2

(flaming) were not included in the slope calculations. No overloading

of the cup was observed for the other materials examined in this study.

The CO^ concentrations recorded by the infrared analyzer include the

CO^ produced by material degradation and animal respiration, as well as the CO

2 content in the ambient air. In analytical runs without animals,

CO

2 generation was always found to be lower than that found in the

animal experiments; only the latter are shown in table 9.

45
According to the test method proposed at the start of the ILE, the

C>2 level should not fall below 18% during the exposure. Although both

the average and the minimum percent 0^ for the 30 minute exposure period

were recorded, only the average reading was used to meet the 18% qualification. The average 0^ concentration remained above 18% for all

materials in the non-flaming mode and at 440°C. In the flaming mode, the

average O

2 concentration fell below 18% for six materials. In five out

of six experiments in which O

2 deficiency was observed, the average O2 level remained above 16%. In the exception, the lowest average O

2 level

recorded was 14.2%. Recent studies reported by Matijak-Schaper and

Alarie [15] show that their animals (mice) were essentially unaffected by

a reduction of the oxygen level from 20.9% (normal atmospheric) to 10%.

Only slight decreases in the average respiratory rate were observed at 9%

oxygen. Based on this information, the criterion for the minimum average

O

2

level in the toxicity test method as described in section 2 was changed to 16%. The test method requires that O

2 be introduced into the

exposure box whenever the 0, concentration decreases below 16% during the

30 minute experiment.

Of the six nitrogen-containing ILE materials examined, modacrylic

produced the largest amount of HCN in both the flaming and the non- flaming modes. Flexible polyurethane generated the lowest amount of HCN.

Three materials, rigid polyurethane, PVC with zinc f errocyanide , and wool,

generated significantly more HCN in the non-flaming mode than in the

flaming mode. Time-dependence curves for CO and HCN (figs. 17 and 18)

illustrate the rate of release of the two gases.

5.4 SUMMARY OF CHEMICAL MEASUREMENTS

The following decisions were made in arriving at the current chemical

analysis system:

(1) measurements of CO, CO

2

, and O

2 should be continuous or every two

minutes

,

46
*(2) the average 0^ level during the 30 minute exposure should not fall

below 16%, and

(3) measurement of HCN is optional.

6.0 ANIMAL MEASUREMENTS

6.1 NEED FOR ANIMALS

In addition to atmospheric chemical measurements, animal exposures

are necessary to assess the toxicity of combustion products. Although

sampling and analytical methods have been developed for many of the

known toxicants produced in a combustion atmosphere, chemical analysis

of all the suspected toxicants would be a formidable task. Even if such

a task could be routinely accomplished, the possibility of missing an unknown or unsuspected toxicant always exists. In addition, the toxicological properties of many of the combustion products are not known and

knowledge of possible interactions is almost non-existent. An animal,

on the other hand, will respond to all the individual toxicants present

and also will respond to the additive, synergistic, or antagonistic

metabolic interactions that the various combinations of chemicals can produce within the body. At the present time, the assessment of the

toxicological effects of material decomposition products does not distinguish between the effects of individual toxicants and the combination

of effects that may occur when a multitude of toxicants is produced.

However, an animal will integrate the combination of effects and react

with a visible or measurable biological response. First, the animal's

reaction demonstrates that a material produces toxic products, then

atmospheric chemical analysis is used to identify the toxicants and to

determine if they are present in sufficient quantities to account for

the observed toxicity.

* New procedures or procedures that have been modified from those proposed in the original test method [7, Appendix A].

47
6.2 TEST ANIMALS

6.2.1 Animal Species. Experiments may be performed using one or more animal species. The use of a single inbred animal species is more

likely to produce better repeatability of quantitative results between

experiments and greater reproducibility between laboratories. The

observation of similar experimental effects in different animal species

increases the probability that the same effect will occur in humans as well. The decision to use one inbred animal species rather than multiple

species was based primarily on economics. Testing materials at three

different temperatures (flaming, non-flaming, and 440°C) and examining

both incapacitation and lethality would be costly enough without

compounding the expense by repeating all the experiments with more than one animal species.

The rat was chosen as the experimental animal because (1) a significant amount of the research in toxicology in general, and combustion

toxicology in particular, has used rodents, either rats or mice; (2) the

available literature constituted a considerable source of valuable

information; (3) the greater size and blood volume of the rat (compared

to the mouse) permitted arterial cannulation and blood samples for

quantitative analysis to be taken during and following the exposures; and

(4) other physiological parameters could be more easily monitored in the

larger animal. The choice o': rats does not imply that a correlation

exists between the effects in rats and humans.

6.2.2 Animal Sex, Weight, Age, and Strain. The use of adult male

rats weighing between 225 grams and 325 grams and 3-4 months of age is

designated in the test method (section 2). The decision to use males

rather than females was based on the desire to reduce all sources of

possible variability, as for example, the female estrus cycle. The

elimination of the female gender, however, introduces the possibility

that a toxic response peculiar to females may be overlooked.

48
The size of the rat was important for two reasons. First, the

animals should be in a growing stage as a weight profile can be used to

determine experimental effects on post-exposure health. Weight loss is

obvious, but subtle changes in rate of weight gain would only be noticeable

in animals whose controls are still gaining weight daily. Second, exces- sively small or excessively large animals presented problems of restrainer

fit. As a variety of strains are permitted by the test method, the age of

the rats (3-4 months) as well as the weight is specified.

Investigators may choose the rat strain. The test method recommends

Fischer 344 rats as they are easy to handle and grow at a slower rate

than other strains. A slower rate of growth permits a longer period of

time during which the animals can be kept before they outgrow the

capacity of the restrainer. Although Fischer 344, Sprague-Dawley , and

Long-Evans rats were used by different laboratories in the interlaboratory

evaluation of the test method, the differences in strains did not affect

the reproducibility of results (NBS report of ILE, in preparation) . It

is advisable, however, to consult the Catalogue of NIH Rodents [16] to

insure that the rat strain chosen does not have a particular susceptibility to disease or potential lung problem which would cause that strain

to be unsuitable for acute inhalation toxicity studies.

6.2.3 Animal Maintenance and Care. Animal care should be performed

according to the procedures in the "Guide for the Care and Use of

Laboratory Animals" [17], In addition, it is recommended that the animals

should be received and kept at least 10 days prior to experimentation

to allow acclimation to the laboratory conditions and to insure the

health of the animals. Normal growth, as determined by daily weighing,

is a good indication of proper care and health. Randomly selected

animals from each batch should be designated as controls, weighed daily,

and kept as long as any of the experimental animals of the same batch.

Animals should be housed individually in a temperature 22°C) and

humidity (% 50%) controlled room. Twelve hours of lighting per day

should be provided, preferably by an automatic timer. Food and water

should be supplied aui libitum . The six experimental animals for each

49
experiment should be chosen randomly from the same batch. If blood

samples are desired during the exposure, cannulation of two of the six

experimental animals should be performed 24 hours prior to the test [18].

On the day of the experiment, the animals should be weighed and then

placed into their restrainers, two of which are modified to provide access

to the cannulae. The animals should not be placed in the exposure chamber

until immediately before the start of the test, since once the animals are positioned in the chamber, due to respiration may increase in the

chamber. Any increase in CO^ prior to the test can"be prevented by

adequate aeration of the chamber. Blood sampling, and the biological

endpoints of incapacitation and lethality will be covered in sections 7 and 6.3, respectively. All animals not used for blood sampling which

survive the exposure are kept and weighed daily for a 14 day post-exposure

observation period. Animals which provide blood samples are sacrificed

following the exposure.

6.3 BIOLOGICAL ENDPOINTS

Toxicity tests measure the effects of a compound upon a living

organism. These effects occur at the molecular, cellular, organ, and/or

whole body level and depend upon the concentration of the compound, the

method of exposure, and the exposure duration. Although mechanism of

action is of interest, such information is not necessary for a first

level screening test designed to assess the relative toxicity of the

combustion products from various materials. Living organisms are necessary to absorb the toxicant, react in some fashion either to the toxicant

directly or to the secondary metabolic products of the toxicant, and

exhibit a biochemically determinable, measurable, or visible endpoint.

This endpoint, which has to be quantitative, repeatable, and reproducible,

is then used to compare the relative toxicity of one material to another

or to a reference material.

The NBS toxicity test method employs the rat as the living organism

for the reasons detailed in section 6.2.1. The biological endpoints

50
monitored during the development of this test method and its interlaboratory evaluation were incapacitation, lethality during the exposure, and

lethality during the exposure plus a 14 day post-exposure observation

period. In addition, changes in blood carboxyhemoglobin content were

monitored to assess whether the primary or sole toxic combustion product

was carbon monoxide (see section 7.0). Questions of the necessity of all

these endpoints and which endpoint provides sufficient information to

assess the relative toxicity of materials were experimentally investigated

by NBS and the other participants during the development of the test

procedure. Another issue that received much attention questioned whether

setting the exposure time and measuring the effect of varying concentrations was preferred experimentally over setting a concentration and

measuring the time-to-ef f ect . The results of an extensive evaluation of

these issues were (1) lethality within the 30 minute exposure time plus

the 14 day post-exposure observation period provided more information

with which to assess the relative toxicity of the combustion products of

materials than either incapacitation or lethality within the exposure

period only, and (2) data across laboratories were more reproducible if

the exposure time was set and the weight of material varied than if

time-to-ef feet was the endpoint. In addition, time-to-incapacitation did

not include the post-exposure effects and thereby failed to provide this

additional, necessary information. The following sections provide the

experimental justification for these decisions.

6.3.1 Incapacitation Models. One recommendation of the Committee

on Fire Toxicology working under the auspices of the National Research

Council [5] stated that animal incapacitation be considered the most

important experimental endpoint as it is directly related to escape

capability. They also recommended that the animals be observed for two

weeks following exposure and that the relative toxicity of materials be

determined by comparison of endpoints with those of reference materials.

They emphasized that simple reproducible techniques should be developed

for assessing incapacitation.

51
A number of animal incapacitation models, none of which are simple,

have been developed to study the toxicity of combustion products.

Examples of behavioral models are: (1) the rotating activity wheel,

(2) the lever actuation conditioned avoidance response developed by

Annau, (3) the rotarod, (4) the greased pole, (5) Alarie’s respiratory

rate model, and (6) hind-leg flexion conditioned avoidance response.

The rotating activity wheel, a round mesh cage which is mechanically

rotated, forces the animal to walk or run continuously depending on the

speed of rotation [191. Experiments at NBS with this model indicated

many difficulties. The main disadvantage stems from the location of

the system within the exposure chamber where: (1) smoke will obscure

observation of the animals, (2) the animals are more likely to experience

heat stress due to whole body exposure, (3) blood samples or other

physiological monitoring during the exposure are extremely difficult, or impossible to obtain, and (4) the toxicants will be deposited on the fur

of the animals with the possibility of subsequent ingestion by the animals

while grooming.

Annau developed a conditioned response behavioral model in which

the animals learned to press a lever to avoid a shock [20]. As the

whole body of the animal was also exposed in this system, many of the

problems of the rotating activity wheel were also experienced with this

method. Visual observation of the animal was not necessary as a computer

registered all shocks received by the animals, an indication of failure

to perform. An additional disadvantage of this system is the long period

of time necessary for training.

In another behavioral model, the rotarod technique, an animal learns

to stay on a rotating rod in order to avoid falling onto an electric grid

and receiving a shock [21]. Training is accomplished in one hour per day

for two days prior to the experiments. Again, whole body exposure is

the main disadvantage of this model.

52
The "greased pole" model, developed by SRI International, involves

teaching rats to prevent an electrical shock by responding to auditory

and visual stimuli and seeking refuge on a pole suspended from the

ceiling of the cage [22]. The shocking mechanism is turned off by the

animal's weight on the pole which is greased to prevent the rat from

staying on it. This system measures both avoidance (the animal responds

to the sensory indicators and prevents the occurrence of the shock) and

escape (the animal responds to the shock by jumping on the pole) mechanisms. The disadvantages are those related to whole body exposure as described above for the rotating activity wheel and the long training

period (four days of intensive training is required).

Marie has developed a biological endpoint based on changes in body

movements (escape movements) and change in respiratory rate due to inhalation of irritants present in smoke [9]. In this model, only the heads

of the animals (mice) are exposed. Since both the escape movements and

respiratory measurements are measured by computerized outputs of pressure

changes in the plethysmograph where each animal is placed, the animals are inaccessible for blood measurements during the exposures. Furthermore,

in a recent report [15], Matijak-Schaper and Alarie concluded that measurement of escape movement was not significantly more sensitive than

measurement of asphyxiation or death in detecting the effect of asphyxiants

such as CO or HCN.

The behavioral model examined most extensively by NBS and the

participants in the interlaboratory evaluation is the hind-leg flexion

conditioned avoidance response developed by Packham [23]. In this model,

one of the rat's hind feet is attached to an electrode such that when the

foot touches a metal plate located below the restrainer, the animal

receives a small electrical shock. The animals learn quickly (approximately 15 minutes) to avoid the shock by keeping the instrumented limb

raised above the metal plate. During the experiments, the animals are considered incapacitated when they no longer respond to the shock. This

model was chosen by NBS as it exposes the rats in a head-only position

which permits blood and other physiological parameters to be monitored

53
as well as incapacitation. Heat stress is minimized since the whole

body is not exposed. A disadvantage of this behavioral system over whole body exposure is the stress the animals undergo when being placed

in the necessary restrainers. A criticism of this model is that no conscious effort is needed by the animal, i.e., the response to the

shock is merely a reflex action and the animal will be close to death

before this response will fail.

Since these models have not been examined under the same conditions

with the same materials, it is not possible to decide on the basis of

experimental evidence which is the best model to assess the incapacitating effect of materials. As each method has both advantages and

disadvantages, the choice of one over the other appears to be a matter

of personal preference. It is clear, however, that no single animal

incapacitation or behavioral model will be equally sensitive or responsive to the bread spectrum of compounds produced from polymer thermal

degradation. With the exception of the respiratory model of Alarie which

measures sensory and pulmonary irritants, all of the above models monitor

the loss of neuro-muscular functions. Ideally, the behavioral model

should measure the overall ability of an animal to escape and should be

a significantly more sensitive indication of toxic combustion products

than a lethality measurement.

6.3.2 Measurement of Incapacitation by the Hind-Leg Flexion

Behavior Model.

6. 3. 2.1 Time-to-Incapacitation. In the experiments performed at

NBS and the other laboratories in the interlaboratory evaluation of the

test procedure, time- to-incapacitat ion was measured for each animal and

a mean time with a standard deviation was calculated for the six animals

exposed in each experiment. In early experiments at NBS, the mass loading was kept constant and the times-to-incapacitation of all six

animals were measured. In this manner, the mean time-to-incapacitation

could be compared for the same mass loading of materials. This procedure

worked better for some materials than for others. Those materials whose

54
combustion products caused post-exposure effects rather than withinexposure effects produced extremely variable results when examined by

this method. Poly (vinyl chloride) is an example of such a material.

Upon thermal decomposition, PVC produces HC£, a potent toxicant and highly

irritating acid gas. The animals start reacting immediately by touching

the plate repeatedly and soon appear incapacitated (failure to respond to

the shock). If they appear incapacitated, the shocking mechanism is

turned off. However, when the animals are removed from the chamber at the

end of the 30 minute test, it is obvious that they are still fully capable

of moving and reacting. The irritating effects of the combustion products

from this material are so intense that the animals fail to react to the

shock. If, on the other hand, the shocking mechanism is not turned off

when the animals appear incapacitated, they soon start reacting again.

This seemingly incapacitated state will recur repeatedly during the exposure. Within the same experiment the actual time of incapacitation varied

widely (table 12) and some animals died before others were incapacitated.

Other materials, mainly those which produced within exposure effects,

showed good repeatable results with the method.

Time- to- incapacitation can be examined in another manner. The

exposure duration can be set (for example, at 30 minutes) and the mean and

standard deviation of the time-to-incapacitation for the exposed animals

can be calculated for different mass loadings of material. The lower

the mass loading, the more time needed to incapacitate the animals.

These points will be represented by a function which asymptotically

approaches a threshold time-to-incapacitation on one axis and a concen- tration of material needed to produce incapacitation in the specified

time limit on the other axis (fig. 19) [ 24 ] . It is important to note,

however, that built into this threshold time and concentration is the

time necessary for the decomposition of the material. Wood, for example,

takes longer to decompose than some thermoplastics.

In section 4.3 of this report, the reasons for not having the

exposure exceed 30 minutes are noted. With the exposure time set at

30 minutes, however, some concentrations of combustion products cause

55
incapacitation in less than the total six animals. Therefore, the mean

and standard deviation of the time-to- incapacitation of all six animals

can not be calculated. In these cases, where two to five animals are incapacitated, a statistical treatment called the Best Linear Unbiased

Estimate of Censored Data (BLUE) is used to estimate the mean and standard deviation [25]. Even this statistical treatment of the data,

however, can not provide many data points at the lower mass loadings

where the mean time-to-incapacitation is longer than 30 minutes.

The mean times-to-incapacitation that were obtained experimentally

or via the BLUE estimate for each material in each mode were used to

best fit a hyperbolic curve (Y = Q + R/X) . Six examples of these

hyperbolic curves for Douglas fir in the non- flaming mode are shown in

figure 20. The hyperbolic equations are shown on each graph. Similar

time-concentration hyperbolas were generated for all the materials in

both flaming and non-flaming modes from the NBS data and that supplied

to NBS by the other laboratories. The Q and R coefficients calculated

for each material in each mode from all the laboratories are presented

in table 13. Visual inspection and comparison of the coefficients

indicate the differences between the curves. The problems that arise

with the use of the hyperbolic curves for the analysis of relative toxicity of the combustion products of materials are: (1) differences in

time to incapacitation of 5-10 minutes are equivalent to 16-30% of the

total 30 minute time frame, i.e., experimental scatter is inevitable,

(2) the 30 minute exposure time limits the number of data points at lower

mass loadings, and (3) comparison of the various curves to determine

relative toxicity of materials is difficult.

6. 3.2.2 EC,_q. Another means of analyzing the incapacitation data

was to determine the ec ^q» the concentration (mass loading of material

divided by the exposure chamber volume) which was necessary to incapacitate 50% of the rats in the 30 minute exposure. The percent of

animals incapacitated at each mass loading tested was plotted on logarithmic probability paper to obtain a concentration-response curve. The

slopes of these curves, their 95% confidence limits, the EC^q’s, and

56
their 95% confidence limits were statistically determined by the method

of Litchfield and Wilcoxon [26]. For the statistical analysis of these

curves, three data points were needed between 0% effect and 100% effect,

e.g., 17% (1/6 incapacitated), 50% (3/6), 83% (5/6). In some cases,

however, a small change in concentration (e.g., 0.5 mg/£) would cause

the number of animals incapacited to change from 0% to 100%. In these

cases, the EC,_q was estimated from the linear plot of the data (fig. 21).

Whenever a value was estimated, the approximate sign ('v-) is placed before

that value and the extremes used to estimate that value are placed in

brackets. Table 14 shows the EC,-q values (those statistically determined

and those estimated) with their 95% confidence limits in parenthesis.

The slopes of the concentration-response curves and their 95% confidence

limits are shown in table 15.

The slope of the curves are important for the toxicological analysis of the materials. The EC,_q of two materials may be the same but one slope may be much steeper than the other (fig. 22). The steep slope

indicates that a threshold concentration is needed before any effect

occurs and that a small increase in concentration will cause all the

animals to react. A less steep slope indicates that the measurable

biological response will occur over a wider concentration range.

6.3.3 Lethality. The most common biological endpoint in toxicology

is the —the concentration which is necessary to cause 50% of the

animal population to die in a set period of time. The proposed test

method required that lethality be monitored during the 30 minute exposure

and a 14 day post-exposure observation period. The animals were to be

exposed to different concentrations in order to generate a concentrationresponse curve similar to that described for the EC^q in section 6. 3. 2.

2

(fig. 21).

The data on each material in each mode (flaming and non-flaming)

were used to calculate an LC^q for the 30 minute exposure and an LC^q

for the 30 minute exposure plus a 14 day post-exposure observation

period using the statistical method of Litchfield and Wilcoxon [26].

57
Tables 16 and 17 show the values and their 95% confidence limits for

the 30 minute data and the 30 minute plus 14 day data, respectively.

Tables 18 and 19 show the slopes and 95% confidence limits of the

concentration-response curves for the for the 30 minute exposure and

those for the LC^ for 30 minutes and 14 days, respectively. Those LC,_q

values that could not be determined statistically were estimated in the

same manner as described for the EC^ in section 6. 3. 2.2, where the

importance of the slope information is also discussed.

Some of the advantages of using lethality as an endpoint are: (1)

LC,_q calculations have been traditionally used in toxicology, (2) the

statistics for handling the data are well documented, (3) the determination of the endpoint is simple, (4) the results are repeatable within

a laboratory and reproducible across laboratories, (5) the concentrations

tested are only limited by furnace size and the explosion limit, and (6)

due to the wider range of concentrations which may be tested, relative

LC^q values of materials can be compared over several orders of magnitude.

6.3.4 Comparison of Incapacitation and Lethality Results. The

purpose of the toxicity test method and the interlaboratory evaluation

has been to develop a test which can be used to assess the toxicity of

combustion products. In the interlaboratory evaluation, both incapacitation and lethality data were collected, analyzed, and compared to determine

whether both types of measurements were necessary. Table 20 and figures

23 and 24 compare the NBS results on the EC,_q, LC<_q (30 minutes) and LC^

(30 minutes + 14 day) data in the flaming and non-flaming modes and at

440°C. An examination of that table and those figures show that most

of the materials produced combustion products with toxicity similar to

that of Douglas fir. The perceived toxicities of the combustion products

of most materials did not change their relative positions regardless of

whether incapacitation (EC^) , the within exposure lethality (LC<-q, 30

minutes) or the lethality for within exposure plus the 14 day postexposure period (LC..^, 30 minutes + 14 day) data were used for the

comparison. However, the combustion products of ABS (flaming mode)

,

FPU (non-flaming mode), PTFE (flaming and non-flaming modes), and PVC

58
(non-flaming mode) caused significant post-exposure mortality. The

within-exposure incapacitation and lethality determinations result in a less sensitive measurement of toxicity, i.e., the animals were not incapacitated or killed during the 30 minute exposure period until the con- centration was considerably larger than the concentration which produced

lethality during the post-exposure period. Therefore, the LC,_q results

for the 30 minute exposure plus the 14 day post-exposure period, which

provided information on the delayed effects, supplied a more complete

picture of the toxic effects of the combustion products of a material

than the within-exposure endpoints.

This conclusion was also reached in a comparison of EC^, LC,_q (30

minutes) and LC<_q (30 minutes + 14 day) data from all the participating

laboratories. To make this cross laboratory comparison, the value from

each laboratory for each material in each mode was normalized to its

Douglas fir data in that same mode. Then the mean of the normalized

values from all the laboratories for each mode was determined. The

results from NBS, which had two sets of Douglas fir data, were kept

internally consistent, i.e., the results of a material which had been

thermally decomposed in furnace "a" were normalized with the Douglas fir

data from furnace "a". In those few cases where data were used from both

NBS furnaces to calculate the or LC^ values, an average value of

the Douglas fir results from both furnaces was used for normalization.

All the normalized values for the LC,_q (30 minutes + 14 day) data were

then ordered from the least toxic to the most toxic. Tables 21, 22, and

23 show this ordering of materials for the flaming, non-flaming, and

440°C modes, respectively. The average normalized values for the LC,^

(30 minutes) and EC^ are all listed on these tables for comparison

purposes. The listing of materials in this manner was not to rank order

the materials but rather to compare methods of analysis (Note 11)

.

Note 11: It is important to note that the results shown in tables 21,

22, and 23 pertain to the particular samples tested during this

study. The materials used were selected to represent a wide

range of properties. No attempt was made to provide statistically valid samples of a given material. Therefore, the

results should not be used to judge any particular class of

material.

59
These results show that the various means of determining toxicity

[LC^q (30 minutes + 14 days), LC,_q (30 minutes), and EC^] provide the same relative ranking of materials (especially if the standard deviation

of those normalized values is considered) with the exception of PVC.

When compared with Douglas fir, PVC is less toxic if the EC,_q in the nonflaming and 440°C modes are considered; it is more toxic if the LC,.q

( 30 minutes + 14 day) data are considered. In other words, since most

animals die during the post-exposure period, PVC appears less toxic when

only the within exposure results are examined.

The above results show that, in most cases, the LC,_q (30 minutes),

and EC,-q provide the same degree of sensitivity in distinguishing the

toxicity of combustion products. However, the LC,_q values that include

the 30 minute exposure plus the 14 day post-exposure observation period

increase the sensitivity of the test to detect those materials that

produce toxic products which are primarily respiratory tract irritants

and cause post-exposure deaths.

In summary, two different methods of comparing the incapacitation

and lethality experimental results have been examined. In both cases,

the lethality results which include the post-exposure effects provide

more information with which to compare and assess the toxicity of the

combustion products of materials than the incapacitation data. It was on the basis of this experimental evidence that the decision was made

to eliminate incapacitation from the test method and to require the

determination of the LC,_q based on the 30 minute exposure plus 14 day

post-exposure observation period.

6.4 ASSESSMENT OF MATERIALS THAT RELEASE TOXICANTS RAPIDLY

The percent lethality due to a toxicant is dependent on both the

exposure time and concentration. The relationship between these factors

may be represented by a three dimensional concentration-time-lethality

figure (fig. 25) [24]. The percent lethality is represented on the

60
vertical axis (z) , concentration and time are represented on the horizontal axes, x and y. The surface can be determined by performing a series of tests at fixed times with varying concentrations or at fixed

concentrations with varying exposure times as suggested by the lines on

the surface in figure 25.

The maximum exposure time to which the animals should be subjected

was set at 30 minutes in this test method. This 30 minute exposure is

shown as a bold line in figure 25. The 50% lethality line drawn on the

surface represents the combinations of time and concentration at which

50% of the animals die. The LC,.q is the point of intersection of the 50%

lethality line and the 30 minute exposure line. For large values of time,

the distance between the lethality surface and the zero concentration

plane (x' ) asymptotically approaches the concentration threshold and is an indication of the toxicity of the combustion products for long exposure

times

.

If the shape of the response surfaces were the same for all

materials, then one could assume that the rank-order of materials would

not change in moving up or down from 30 minutes. In fact, the surfaces

are likely to be somewhat different and the rank-order may indeed change.

If there is a question about toxicity for a different time, the

should be redetermined for that time. If characterization of a large

portion of the response surface is desired, LC,^ data should be obtained

at several additional times. The cost of doing these experiments will

be higher than for just the 30 minute test; the increased assurance that

false negatives will not occur must be weighed against that increase

in cost.

As an optional procedure in this test method, a single 10 minute

exposure was chosen at the approximate maximum capacity of the furnace

for most materials (30 mg/2,). This 10 minute exposure was performed on PVC and PVC with zinc ferrocyanide to illustrate the capability of the

test to further differentiate between the combustion toxicity of materials

61
which had comparable LC^^’s for the 30 minute exposure and 14 day observation period. Table 24 shows the results of this test. PVC with zinc

ferrocyanide produced 100% incapacitation (measured by righting reflex of

the animals) in the 10 minutes at all three temperatures, flaming, non- flaming and 440°C. Although some deaths occurred during the 10 minute

exposures, 100% of the animals were dead by the end of the 14 days

following this 10 minute insult. In all cases, sufficient hydrogen

cyanide was produced to account for deaths in a 30 minute exposure, but

whether these concentrations of hydrogen cyanide were sufficient to cause the 10 minute deaths is not known.

The PVC tested in this study, on the other hand, caused no incapacitation or death during the exposure. Only one out of the 30 animals

tested died during the 14 day post-exposure period. This PVC did not

produce effective concentrations of toxicants as rapidly as the PVC with

zinc ferrocyanide.

On the basis of these experiments, the decision was made to add this

additional 10 minute experiment at a 30 mg/£ concentration as an optional

supplement to the test method to provide a qualitative indication of the

performance of materials that produce toxicants rapidly. This additional

test may be performed on materials except those with an LC,_g (30 minutes

and 14 days) of less than 2 mg /£. Because of the possible hazard to

laboratory personnel, these materials, which are toxic at very low con- centrations, should not be examined at the 30 mg/£ concentration. The 10

minute exposure test should be run at least twice at the temperature

condition (flaming or non-flaming) which proved to be most toxic in the

LCj-q determinations. If 50% or more of the animals from all the 10

minute exposure tests die, the material would be considered capable of

rapidly producing toxicants.

6.5 SUMMARY OF ANIMAL MEASUREMENTS

The following list summarizes the major decisions regarding the

animal measurements:

62
(1) one inbred animal species should be used,

*(2) adult male rats weighing between 225 and 325 grams and 3-4 months of

age are designated,

(3) the choice of rat strain is not specified, but Fischer 344 is recommended,

(4) animals should be kept 10 days before experiments and weighed daily

from day of arrival to the end of the 14 day post-exposure observation period,

*(5) animals used for blood measurements should not be kept for the 14

day post-exposure observation period,

*(6) the biological endpoint should be the LC,.q calculated for the 30

minute exposure and 14 day post-exposure observation period; the

biological endpoint should not be the EC,.q, which is based on percent

of animals incapacitated, nor the time-to-incapacitation, and

*(7) a 10 minute animal exposure to 30 mg/£ has been added to the test

procedure as an optional supplement to provide a qualitative indication of the performance of materials that produce effective

concentration of toxicants rapidly.

7 . 0 BIOLOGICAL MEASUREMENTS

7.1 BLOOD ANALYSIS

Carbon monoxide has been implicated as the primary toxicant res- ponsible for fire deaths [27, 6]. Our experimental results on animals

presented here show that levels of carboxyhemoglobin (COHb) found in the

blood in many smoke inhalation cases are not sufficient to account totally

for the resultant deaths. While CO is definitely a contributing agent in

many of these fire fatalities, other toxicants and/or factors, such as heat stress, oxygen deficiency, and prior health problems, also need to

be considered.

*New procedures or procedures that have been modified from those proposed in the original test method [7, Appendix A],

63
Hemoglobin, the oxygen-carrying protein of red blood cells, has a reversible affinity for CO which is approximately 200-250 times its

affinity for 0

^ [28], The binding of CO to hemoglobin results in the

rapid formation of COHb and the prevention of the formation of oxyhemoglobin (O^Hb) , the means whereby oxygen is normally transported to the

cells. In the presence of CO both the oxygen carrying capacity of the

blood and its oxygen releasing capacity are reduced, producing an oxygen

deficiency at the cellular level greater than that produced by an equivalent reduction in the concentration of atmospheric oxygen or concentration

of hemoglobin.

Each laboratory participating in the interlaboratory evaluation of

the test method analyzed the animal blood for COHb and ©

2^. These blood

values are influenced by the method and the time of sampling.

Various methods were used to obtain blood. If the animals were

cannulated, arterial blood was taken during the exposure without removing

the animals from the exposure chamber. If the animals were not cannulated, the method of sampling blood was left to the discretion of the

investigator. Post-exposure cardiac puncture, intraorbital venous puncture, or the dorsal aorta were used to obtain blood. The values of

C^Hb will depend on whether the blood sample is arterial, venous or a mixture. Also, anesthesia supplied to the animal before surgery to

obtain blood from the dorsal aorta or the heart causes a decrease in the

respiratory rate and a lower C^Hb value. Therefore, unless arterial

cannulation is required by the test method, the C^Hb will not be reproducible across laboratories. Consequently, the test method was modified

to require only COHb measurements which show only minor differences

between arterial and venous blood.

The time at which blood is taken also influences blood COHb and

02Hb values. Blood from live cannulated animals should be taken just

before the end of the exposure. Non-cannulated animals have to be

removed and some recovery can occur in live animals before the blood is

sampled. The animals recover rapidly from carbon monoxide exposure and

64
the levels of COHb reflect this recovery. Figure 26 shows the NBS

results on the formation of COHb and reduction of ©

2

^

during a 30 minute

exposure to an average concentration of 4100 ppm of pure CO. The very

rapid recovery rate following the exposure is also shown and emphasizes

the need for rapid blood sampling procedures. Figure 27 shows the percent COHb determined at the end of each exposure to non-flaming Douglas

fir plotted against the average concentration of CO integrated over the

30 minute exposure for cannulated and non-cannulated animals from seven

laboratories. The solid and dashed lines represent the least squares

linear regression analyses of all the points from cannulated and non- cannulated animals, respectively, until the loading where COHb levels

off. The animals did not load more than 86% COHb. For cannulated

animals, COHb values are higher because these animals experience no recovery period. COHb values are generally lower for non-cannulated

animals because the animals must be removed from the chamber before

blood is taken, allowing some recovery to occur.

The test method, therefore, provides that when blood is taken from

non-cannulated animals, it must be obtained within five minutes of the

end of the exposure. Regardless of cannulation, all animals that are used for blood sampling are not to be kept for the 14 day observation

period as both the process of cannulation and the removal of blood have

added to the toxicological insult.

7.2 CORRELATION OF COHb, CO, AND TOXICITY

Pure gas experiments using the NBS equipment (except the furnace)

have shown that an average concentration of 5000 ppm of CO is necessary

to kill 50 percent of the rats in 30 minutes. This CO concentration

results in an average COHb level of 89 percent in the blood immediately

prior to the end of the 30 minute exposure (cannulated animals). The

COHb level immediately prior to the end of the 30 minute exposure at the

LC

50 mass loading should then be an indicator of the extent to which CO

contributes to the overall combustion product toxicity of a material.

Figure 28 illustrates how this COHb level can be determined. The COHb

65
levels that are obtained at the end of each exposure are plotted against

the mass loading/chamber volume. Then the (30 minutes + 14 day)

value is superimposed on the graph and the percent COHb at that mass loading is determined. The COHb values for the EC^q and LC,.q (30 minute)

values can be obtained from this curve in a similar manner.

Tables 25 and 26 show the COHb levels obtained in this way using the

NBS test results and corresponding average CO, average HCN, and LC^q (30

minutes + 14 days) for flaming and non-flaming combustion for eleven of

the materials used in the ILE. The NBS pure CO study showed no postexposure deaths. When post-exposure deaths are observed, there are almost certainly other contributing factors.

Within-exposure deaths occurring at the LC,_q (30 minutes + 14 days)

together with COHb levels below 89 percent and CO concentrations less

than 5000 ppm also indicate that factors in addition to CO must be con- sidered when one is evaluating the toxicity of combustion products.

Figure 29 shows, for NBS measurements, the relationships between

COHb and average CO concentration at the LC,.q (30 minutes + 14 day) values

of the eleven materials under both flaming and non-flaming conditions.

The results for materials which produce HCN or HC£ are identified in

figure 29. This further illustrates that the COHb measurement required

in the test method can be a useful indicator of the likely presence of

other toxic gases, although it should not be used to rule out the

presence of other gases.

8.0 SUMMARY OF CHANGES TO THE TEST METHOD

The results of early work, sponsored by the Products Research

Committee, on the design of a test procedure were published as a report

of the National Bureau of Standards [7]. Subsequent work at NBS and

technical information provided by an ad hoc working group representing

academia, industry, and government resulted in the following changes to

the earlier procedure:

66
examination of materials at 440“C is now optional,

°the recommended size of the cup furnace has been increased

from 300 m£ to 1000 mi-,

°the average chamber temperature in the vicinity of the noses of

the animals for the 30 minute exposure must be below 40°C,

°the minimum average oxygen level permitted in the chamber is 16%,

°the weight range of the rats has been increased from 200-300

grams to 225 to 325 grams and an age restriction to between 3

and 4 months has been introduced,

°for the 30 minute exposures, the only biological endpoint now

required is an LC,.q (the concentration which causes lethality

in 50% of the animals in the 30 minute exposure including a 14 day

post-exposure observation period). The incapacitation endpoint has

been eliminated,

°an optional animal exposure at a concentration of 30 mg/S, for 10

minutes followed by a 14 day post-exposure observation period has

been added for some situations,

“blood from non-cannulated animals must be taken in the first

5 minutes after the end of the exposure,

“oxyhemoglobin and total hemoglobin measurements are no longer

required, and

“pathological examination of the animals that die during exposure

or are sacrificed is now optional.

67
9.0 FUTURE WORK

The test method presented in this report can be used to assess the

toxicity of combustion products of materials under specified laboratory

conditions and is just a first step towards predicting the toxic hazard

that a material would pose in an actual fire. To evaluate the toxic

hazard, a technique must be developed to combine information on the

quantity of material, its configuration, the proximity of other combustibles, the volume of the compartment to which the combustion products

may spread, the ventilation conditions, the ignition and combustion

properties of the material, the presence of ignition sources, the

presence of fire protection systems, the occupancy of the building, and

other pertinent factors.

The test method itself has certain limitations resulting from the

use of the cup furnace. These limitations relate to the testing of low

density materials, many composite materials, and some products with

layered construction. A radiant heating system as an alternate combustion module may be better able to address these problems and will be

studied further at NBS.

In assessing the overall toxic hazard posed by a material or combination of materials the rate of release of toxicants is an important

factor in the determination of the time available for egress from a burning structure. A system to measure the continuous weight loss of a sample during a test would provide some additional information on this

subject. NBS plans to study this system as a part of its work on a radiant furnace.

The temperature of the gases in the exposure chamber can influence

the effect on the animals. Improved control of this temperature would

enable the test method to be used to determine temperature effects alone

and in conjunction with toxicants.

68
A base of information on the toxic effects of known concentrations

of pure gases and combinations of gases at different atmospheric temperatures in this system is needed as background for the evaluation of total

toxic hazard.

Additional study of the 10 minute test or other means for assessing

the rapid evolution of effective concentrations of toxic combustion

products is necessary.

In the evaluation of total toxic hazard generated by a fire situation, an incapacitation model should provide additional information

necessary to the prediction of safe egress. At the present time, the

behavioral incapacitation models that have been studied are not significantly more sensitive than the measurement of lethality. Additional

research in the area of incapacitation models is needed.

10.0 ACKNOWLEDGMENTS

We gratefully acknowledge the help of Mr. Emil Braun and Mr. Richard

Peacock for designing and writing the many computer programs which

improved the efficiency of data collection and analysis. We also

acknowledge Dr. James J. Filliben for the many helpful discussions and

guidance with regard to statistics in general and the BLUE technique in

particular. In addition, we thank Ms. Mary Diephaus and Ms. Alison

Durham for their expert use of computer graphics in preparing many of

the figures.

69
11 . 0 REFERENCES

1. Highlights of fire in the United States, 2nd Edition. Federal

Emergency Management Agency, U.S. Fire Administration; 1981 April

26 p

.

2. Preview, Residential Fires in the United States, Federal Emergency

Management Agency, U.S. Fire Administration, 1979.

3. Birky, M. M. Hazard characteristics of combustion products in

fires: the state-of-the-art review. Nat. Bur. Stand. (U.S.)

NBSIR 77-1234; 1977 May. 48 p.

4. Committee on Fire Safety Aspects of Polymeric Materials. Smoke and

toxicity (combustion toxicology of polymers). Vol. 3, Publication

NMAB 318-3, Nat. Acad. Sci., Westport, CT: Technomic Publishing

Co . ; 1978. 55 p.

5. Committee on Fire Toxicology. Fire Toxicology: methods for

evaluation of toxicity of pyrolysis and combustion products.

Report No. 2, Nat. Acad. Sci., Washington, D.C. 1977 August. 34 p.

6. Lyons, J. W. ; Fristrom, R. M. ; Becker, W. E. ; Clayton, J. W.

;

Emmons, H. W. ; Glassman, I.; Graham, D. L. ; Long, R. ; McDonald,

D. W. ; Nadeau, H. G. ; Products Research Committee. Fire research

on cellular plastics: the final report of the Products Research

Committee. [Washington, D.C.], 1980, 213 p.

7. Birky, M. M. ; Paabo, M. ; Levin, B. C. ; Womble, S. E. ; Malek, D.

Development of recommended test method for toxicological assess- ment of inhaled combustion products. Nat. Bur. Stand. (U.S.)

NBSIR 80-2077; 1980 September. 63 p.

70
8. Kimmerle, M.G., Aspects and methodology for the evaluation of

toxicological parameters during fire exposure. J. Comb. Tox. 1:

4-51; 1974.

9.

Alarie, Y. C. ; Anderson, R. C. Toxicologic and acute lethal

hazard evaluation of thermal decomposition products of synthetic

and natural polymers. Tox. Appl. Pharm. 5JL: 341-362; 1979.

10. Fire tests - reaction to fire - ignitability of building products.

Draft Technical Report DTR 5657, ISO/TC 92 SC 1 N36, 1981 June.

11. Potts, W. J. ; Lederer, T.S. A method for comparative testing of

smoke toxicity. J. Comb. Tox. 4^ 114-162; 1977.

12. MacFarland, H. N. Respiratory toxicology, chapter 5 in Essays

in Toxicology, W. Hayes, ed. New York: Acad. Press; 121-154;

1976.

13. Standard guide for measurement of gases present or generated during

fires. ASTM Standard E 800-81; 1981.

14. Paabo, M. ; Birky, M. M. ; Womble, S. E. Analysis of hydrogen

cyanide in fire environments. J. Comb. tox. b} 99-108; 1979.

15. Matijak-Schaper , M. ; Alarie, Y. A. Toxicity of carbon monoxide,

hydrogen cyanide and low oxygen. J. Comb. Tox. 9^: 21-61; 1982.

16. Hansen, C. T. ; Potkay, S.; Watson, W. T. ; Whitney, R. A. NIH

rodents, 1980 catalogue. Dept. Health and Human Services, Public

Health Service, NIH Publication No. 81-606. 1981 April. 253 p.

17. Committee on Care and Use of Laboratory Animals; Guide for the care and use of laboratory animals. DHEW publication No. (NIH) 78-23.

U.S. Dept, of HEW, Public Health Service, National Institutes

of Health. 1978.

71
18. Packham, S. C.; Frens, D. B. ; McCandless, J. B. ; Petajan, J. H.

;

Birky, M. M. A chronic intra-arterial cannula and rapid technique

for carboxyhemoglobin determination. J. Comb. Tox. 3^: 471-478; 1976.

19. Smith, P. W. ; Crane, C. R. ; Sanders, D. C. ; Abbott, J. K. ; Endecott,

B. Effects of exposure to carbon monoxide and hydrogen cyanide.

Proceedings of symposium on Physiological and Toxicological Aspects

of Combustion Products; 1974 March 18-20; Salt Lake City, Utah.

Nat. Acad. Sci. Washington, D.C., 1976, pp. 75-88.

20. Annau, Z. Behavioral toxicity of cellular plastics. Final report

to Products Research Committee, Nat. Bur. Stand. 1979 June. 23 p.

21. Hartung, R. ; Ball, G. L. ; Boettner, E. A.; Rosenbaum, R.

;

Hollingsworth, Z. R. The performance of rats on a rotarod during

exposure to combustion products of rigid polyurethane foams and wood.

J. Comb. Tox. 4: 506-522; 1977.

22. Pryor, G. T. ; Dilley, J. V.; McKee, R. G. ; Martin, S. B. Behavioral

techniques in fire toxicology. Proceedings of First California

Conference on fire toxicity, 1979 August 21-22, San Francisco,

California, pp. 1-27.

23. Packham, S. C. ; Jeppsen, R. B. ; McCandless, J. B. ; Blank, T. L.

;

Petajan, J. H. The toxicological contribution of carbon monoxide

as a component of wood smoke. J. Comb. Tox. _5: 11-24; 1978.

24. Packham, S. C. ; Hartzell, G. E. Fundamentals of combustion toxicology

in fire hazard assessment. J. Test. & Eval. 9^ 341-347; 1981.

25. Sarhan, A. E. ; Greenberg, B. G. Contributions to order statistics.

New York, London: John Wiley & Sons, Inc.; 1962.

72
26 . Litchfield, J.T., Jr.; Wilcoxon, F. A simplified method of

evaluating dose-effect experiments. J. Pharmacol, and Exp.

Therapeut. £6: 99-113; 1949.

27. Birky, M.M. ; Halpin, B.M. ; Caplan, Y.H. ; Fisher, R.S.;

McAllister, J.M. ; Dixon, A.M. Fire fatality study. Fire

and Materials 3: 211-217; 1979.

28. Ginsberg, M.D. Carbon monoxide. Chapter 26 in Experimental and

Clinical Neurotoxicology . P.S. Spencer and H.H. Schaumburg, eds.

Baltimore, London: Williams & Wilkins; 1980. pp. 374-394.

29. Products Research Committee. Materials bank compendium of fire

property data. Nat. Bur. Stand. (U.S.), [Washington, D.C.] 1980

February.

73
'• '

-
GAS

SAMPLING

PORT

v

X“

PRESSURE

RELIEF

PANEL

74

Figure

1.

Exposure

chamber.

CHAMBER

CONSTRUCTION

MATERIAL:

75

Figure

2.

Details

of

exposure

chamber.

1000

ml

QUARTZ

BEAKER

92

mm

0.0.

15

cm

high

76

Figure

3.

Pyrolysis/combustion

furnace.

77

Figure

4.

Schematic

of

animal

restrainer.

o

78

Figure

5.

Exposure

chamber

with

separate

furnace.

79

Figure

6.

Radiant

furnace

cone.

80

Figure

7.

Animal

restrainer.

AVERAGE

TEMPERATURE

(°C|

MAXIMUM

TEMPERATURE

(°C)

120 r

100

FLAMING (a)

U FLAMING (b)

H NON-FLAMING (a)

NON-FLAMING (b)

FI/

/

/

(a) Small furnace

(b) Large furnace

/

/

/

/

60

40

20

0

ABS DFIR FPU MOD PPS PSTY PVC PVCZ REDO RPU WOOL

40 C C

Figure 8. NBS exposure chamber temperatures at animal nose levels.

Top: Maximum temperatures.

Bottom: Average temperatures.

81

COo) 3HniVa3dW31 3S0N

82

TIME

Cm

i

nu t

es)

Figure

9.

Chamber

temperature

at

animal

nose

positions

during

30

minute

exposure

to

flaming

wool

and

Douglas

fir.

(NSS

data.

Furnace

temperature

for

flaming

wool

was

675 C

and

for

flaming

Douglas

fir

was

490°C.]
:
0.5^/min.

cc

t

83

Figure

10.

Schematic

of

NBS

gas

analysis

system.

84

MASS

LOADING

,

/£]

CHAMBER

VOLUME

1

U

J

Figure

11.

Carbon

monoxide

measurements

averaged

over

the

30

minute

flaming

material

decomposition

plotted

against

the

mass

loading/chamber

volume.

The

length

of

least

squares

linear

regression

line

denotes

the

range

of

mass

loadings

tested.

AVERAGE

CO

(ppm]

0 10 20 30 40 50

MASS LOADING , /£]

CHAMBER VOLUME

1 8/

Figure 12. Carbon monoxide measurements averaged over the 30 minute non-flaming

material decomposition plotted against the mass loading/chamber volume.

The length of the least squares linear regression line denotes the range

of mass loadings tested.

85

ID

CM

O

CO 1

(uidd) N3H 30VH3AV

86

§

MASS

LOADING

.

.

CHAMBER

VOLUME

1

J

Figure

13.

Hydrogen

cyanide

measurements

averaged

over

the

30

minute

flamin

g

material

decomposition

plotted

against

the

mass

ioaning/chamber

volume.

The

length

ot

the

least

squares

linear

regression

analysis

line

denotes

range

of

mass

tested.

in

CM

[uidd) N3H 39VU3AV

87

CHAMBER

VOLUME

Figure

14.

Hydrogen

cyanide

measurements

averaged

over

the

30

minute

non-flamin

g

material

decomposition

plotted

against

the

mass

loading/chamber

volume.

The

length

of

the

least

squares

linear

regression

analysis

line

denotes

range

of

mass

loadings

tested.

4000

(ludd) 00 30VH3AV

88

MASS

LOADING/CHAMBER

VOLUME

(mg/I)

Figure

15.

Overloading

of

furnace

capacity

as

seen

with

non-flaming

decomposition

of

Douglas

fir

in

the

NBS

large

furnace.

Small

furnace

had

similar

results.

5000 o o o o o o o O o

o o o o o o o o o

LO o If) o in o LO o LO

cO CO OJ OJ

(uudd) 00 30VH3AV

MASS

LOADING/CHAMBER

VOLUME

(mg/!)

Figure

16.

Overloading

of

furnace

capacity

as

seen

with

flaming

decomposition

of

Douglas

fir

in

the

NBS

small

furna

Similar

results

were

seen

with

large

furnace.

0009

a® o» ® o. D o o aa p EEEEEEEEEEE

mK^OcpfpSSpg

Sfe&S&SSlglg&I

+0 0 < *

o o o o o o o o o o o

o o o o o o o o o o o

LO o in o in o in o in o in

in in nL CO CO OJ OJ vH

o

CO

in

OJ

o

OJ

m^rH

LO

O

(uudd) 00

90

TIME

(minutes)

Figure

17.

Carbon

monoxide

generation

from

ILE

materials

decomposed

in

the

non-flaming

mode

at

various

mass

loadings

(NBS

results).

CO

LO

<\J

<S

<\J

LO

LO

s>


 s> £> <s <s <s 
 
 L0 S> LO s> LO

CO C\J 0J

——

<o

cuE

03

a>

C/3 oo

(U T3

<A

COa> ^ co W E ^

gp

d =

»-C +»• w

•— e c o c o w £

a> Lu o

z: is H =

(/) ^ % E M

H- 03 O GO

*£3 00

SO z

03i

03

C/3 b£

CO

CO

C ujdd 5 noh

91

C u !“0 N0IlVlI0VdV3NI-01“3WIl

92

TIME-TO-INCAPACIT

ATION

(min]

Figure 20. Time-to-incapacitation vs mass loading/chamber volume hyperbolas for Douglas fir in the

non-flaming mode from six laboratories. (Symbols refer to the mean and standard deviation

of the times-to-incapacitation of the 6 animals tested at each mass loading.)

93

MASS LOADING , n mg/I

CHAMBER VOLUME

1 6 1

Figure 21. Concentration-response curves resulting from animal incapacitation, death within

exposure (30 min ) and death both within and post-exposure (30 min + 14 days)

from the thermal decomposition of wool in the flaming mode.

94

PERCENT

EFFECT

MASS LOADING , ,« CHAMBER VOLUME

S

Figure 22. Concentration-response curves depicting importance of slope information, i.e., LC50

data are the same, but the effective concentration range differs.

95

o

96

Figure

23

.

Comparison

of

materials

by

their

EC

50

,

LC50

(30

min )

and

LC50

(30

min

+

14

days)

after

flamin g

decomposition

(NBS

data).

(Symbols

referring

to

the

same

material

are

connected

by

lines

for

easier

identification

and

not

to

imply

a

mathematical

functional

relationship.)

o

if

1°oo o

<d *= T3

tofl Ere

re

reo

03 03

re — aj

</> •—

>» <2

re re X3 03

CO

a>

^-o oS

LO

O o a>

re ou

03re E .2

sioEo 2 _i Ere

<—> oo LO a>

03 «-* 5 b£

CO 4-> •r; re

re -o E

“"oo

00

CM

03bA

97

a

mathematical

functional

relationship.)

ZERO

CONCENTRATION

PLANE

X

98

CONCENTRATION

—

(mg/I)

Figure

25.

Three

dimensional

representation

of

the

relationship

between

concentration,

time,

and

lethality.

(Figure

modified

after

Packham

and

Hartzell

(24).

99

TIME

(min)

Figure

26.

Withinand

post-exposure

changes

in

carboxyhemoglobin

and

oxyhemoglobin

in

live

cannulated

rats

afiei

a

30

minute

exposure

to

an

average

concentration

of

4100

ppm

of

carbon

monoxide.

3

O C3 CD O CD

co in

^ co cm

QHOO %

o

100

0

1000

2000

3000

4000

5000

6000

AVERAGE

CO

(ppm)

Figure

27.

Effect

of

blood

sampling

before

end

of

exposure

(cannulated

animals]

and

after

exposure

(non-cannulated

animals).

Results

from

Douglas

fir

in

the

non-flaming

mode

from

seven

laboratories.

DETERMINATION

OF

COHb

AT

ECS0

AND

LC50

qHoo %

101

001 £

Q.awOH

h-<

CLH

LUUO

LUaHXooo

CD

CL<O

LU

CD<

CL

IU>< C JO Nia0190W3 HAX0adV0

a>>

0303

00>»

ra

00 £Eocoso

03 4-» *-> ra03oE

rau

ra

bx> oE

raxo

~E

rau

03 75' ra +3 % ra £ » £ CO

00

00 00 .11

ra *—< « ~

os E

05

CM

ra

bfl

102

TABLE 1

Participants of the Ad Hoc Working Group

Organization

Armstrong World Industries, Inc.

BETR Sciences Incorporated

The B. F. Goodrich Co.

Carnegie-Mellon University

Representatives

H . J . Roux

S . Packham

M. M. O’Mara

S . Gad

J. Dorko

Consumer Product Safety Commission

(U.S. Government)

J. McLaughlin

R. Orzel

S . Womble

Dow Chemical Co.

E.I. duPont de Nemours & Co.

Federal Aviation Administration

(U.S. Government)

W. Potts

B. Burgess

R. W. Hartgrove, Jr.

C. Lapin

C. Reinhardt

S. Williams

C. Crane

D. Sanders

E. Podolak

Harvard University D. Dressier

R. Sprenger

The Johns Hopkins University Z . Annau

P. McGuire

Johnson Space Center H. Kaplan

(U.S. Government)

Monsanto Co. W. Fitzgerald

National Aeronautics and Space Administration T. Halstead

(U.S. Government)

National Bureau of Standards

(U.S. Government)

M. Birky

A. Fowell

B. Levin

M. Paabo

103
Table 1 (continued)

Organization Representatives

Owens-Corning Fiberglas Corporation J. Hadley

J. Prusaczyk

D. Thomson

Southwest Research Institute G. Hartzell

Weyerhaeuser Co. R. R. McNeil

H. Stacy

University of Arizona J. W. Clayton

University of Michigan R. Hartung

University of Pittsburgh Y. Alarie

R. Anderson

University of Utah D. Farrar

104
TABLE 2

List of Materials

Material Description Abbreviations

Acrylonitrile butadiene styrene pellets ABS

Douglas fir slabs 10" x 10" x 1" DFIR

n ^ Flexible polyurethane^* flexible foam FPU

Modacrylic knit fabric MOD

Polyphenylsulfone pellets PPS

Polystyrene^’^ rigid foam PSTY

Polytetrafluorethylene resin PTFE

Poly(vinyl chloride) pellets PVC

Poly (vinyl chloride) with

zinc ferrocyanide

pellets PVCZ

Red oak flooring boards REDO

P c Rigid polyurethane rigid foam RPU

Wool unbleached unwoven fibers WOOL

p: PRC material was obtained from the Products Research Committee, Office of

Standard Reference Materials, National Bureau of Standards, Washington, D.C.

20234 [29]. a: GM-21; b: GM-51; c: GM-30.

It is important to note that the results shown in tables 21, 22, and

23 pertain to the particular samples tested during this study. The

materials used were selected to represent a wide range of properties.

No attempt was made to provide statistically valid samples of a given

material. Therefore the results should not be used to judge any

particular class of material.

105
Interlaboratory

Evaluation

of

Douglas

Fir „ s # , CT> CO oo cn »— • • • • • • • —«* CM CO ,

o 1

r^- CO

UO CO LO CO • cr o e i 1 1 1 1 1 1 D •r— | E lo o CM o CM cn r—

(O • • • • • • • • >

l 00 CTi CM LO CO 00 CO r—

in Li_ CM CO CM CO CO CO CM CM P -o - V s«/ ' <* to CO CO o CO o 00 00 O

"D • lo LO 00 O0 00 1

cn cn o

CO CM CM co <3- CO CM CO

cn

01

+-> neocooLO o

>ll o

+-> rC

s_o

jD

rO oI— C\J CO Lf> rOtoCD

JD

ID

CD 00

cr ^ 

„ ^ 

^ N . V *

-N E CO CO O ID CO 00 00 CM

•r— • E cn CO CO cn CO LO in cn CM

<T3 CO CO CM CO CM CM CO

4- 1 1 1 1 1 1 i i 1 E LO cn CO cn o CM CO O • • • Z CM r— cn o LO o r-^ CO

r— CM CM l CM r—- CM r— r— V ^ ^ -- * *"—X* »». ^ ** r". CO 00 o cn 00 LO CO CO CO LO o CM 00 ^M 1 CM CM CM CM CM CM CM

</! 4-> E -o

•r- 0) r— oo

01 r— u o E r-_ 01 Ol 01 •r— u a -o

ro 03 (/) 01 E E 4- +j m J- i- E 01

4->

OO

O CO

•r— 4- 4-

U E 03

•r* r— 01 S-S "O 4-1 LO r— p— Ol LO 01 03 cn fC t- cn +-> *u

ai E to -— ro + 1 o CO r- E 4-> E r— *r— E E O) oo (D 4-> cn

ro TD CO co 01

m •r—

CL) •r— z: Z E O) 01 S 4-EOu ro J3 UU O)

106

*In

this

table

and

subsequent

tables,

the

numbers

quoted

are

as

calculated

from

the

data

provided

by

various

laboratories.

The

95%

confidence

limits

reflect

only

statistical

variations.
Modifications

of

the

Experimental

Procedure

107
TABLE 5

Toxicity of Modacrylic at Different Temperatures

Mode

LC,

Q

, 30 minutes + 14 days a Temperature(°C) mg/T (95% confidence limits)

Flaming 760 - 775 7. 1(6. 4 - 7.9)

Non-Flaming

710 - 720 7. 8(6. 3 - 9.7)

445 - 460 10.0(6.9 - 14.4)

390 - 400 13.6(10.7 - 17.3)

295 - 305 21.8(18.4 - 25.8)

250 - 200260 ~23.8[17.0 - 28.

3

1

>22.

6

1

a: data from laboratory 4.

b: for explanation of superscripts, see legend to table 16 .

108
TABLE 6

Single Versus Multiple Pieces of Douglas Fira

Mass Loaded Number CO Incapacitation Lethality

Chamber Vol. Pieces (ppm-min) 30 min 30 min 30 min + 14

(mg/ i) (%) (%) days (%)

20.25 1 50100 60 0 50

20.05 2 68300 60 0 50

30.35 1 70400 100 16.7 100

30.15 3 71800 100 16.7 80

41.41 1 - 100 50 100

40.20 4 71100 100 83.3 100

NBS data from non- flaming mode. 440°C.

Mean time (min:sec) + standard deviation

Time to

^ Incapacitation

29:23 + 4:27

29:45 + 1:38

25:16 + 2:57

23:09 + 4:08

25:55 + 1:01

20:26 + 4:10

109
1ABLE 7

Maximum Chamber Temperatures During Animal Exposures*

Material Laboratory Flaming Non-flaming 440

# (°C) (°C)

ABS 5 33 29 26

6b 40 32

DFIR 2 40

3 32

4 41 35

6a 42 31

6b 37 41

FPU 6a 47 30

6b 64 33

MOD 2 37

4 40 38 34

5 40 36 31

6a 37 38 28

6b 33

PPS 2 43 39 30

4 49 34

5 31 32 24

6b 53 39

PSTY 2 45 30

6a 65 33

6b 56 36

PTFE 4 38

PVC 6b 37 35 35

PVCZ 2 43 40 30

6b 37 40 33

REDO 5 34 30

6a 37 29

6b 46

RPU 4 29

6b 40 31

WOOL 2 50 34 31

6a 109 36

6b 36

*Temperatures were taken at the level of the animals' noses •

a: NBS small furnace

b: NBS large furnace

c: For abbreviations of materials, see table 2.

110
TABLE 8

NBS Carbon Monoxide Production Per Unit Mass Loading*

Chamber Volume

Material Flaming

Mean Std. Dev.

PITM

mg/1

Non-Flaming

Mean Std. Dev.

mg/l

440°C

Mean Std. Dev.

2pm_

mg/l

ABS (b) 75 16 22 2.5 -

DFIR (a) 76 6.7 110 19 _

(b) 83 7.2 118 21 -

FPU (a) 19 1.8 39 18 _

(b) 26 1.5 30 19 -

MOD (a) 77 34 82 2.4 35 1.8

(b) - - 27 10

PPS (b) 183 17 470 26 -

PSTY (b) 34 3.6 1.8 0.3 -

PVC (b) 54 19 32 5.2 14 3.7

PVCZ (b) 146 12 101 10 35 6.0

REDO (a) 57 9.4 83 7.5

(b) 37 2.4 - -

RPU (b) 127 12 45 8.8 -

WOOL (a) 25 4.1 39 7.8

(b) 25 4.3 12 1.9

*Mean of Average gas concentration (ppm) for each 30 minute exposure

Mass loading/chamber volume (mg/l)

(a) small furnace

(b) large furnace

111
TABLE 9

NBS Carbon Dioxide Production Per Unit Mass Loading*

Chamber Volume

Material Flaming Non-Flaming 440 °C

Mean Std

ppm

mg/1

. Dev. Mean Std. Dev.

PPM

mg/1

Mean Std

PPmmg/1

. Dev

ABS (b) 550 58 170 15 -

DFIR (a) 690 83 260 88 —

(b) 930 71 300 70 -

FPU (a) — 115 53 —

(b) 1200 17 130 27 -

MOD (a) 900 400 1000 240 450 160

(b) - - 490 78

PPS (b) 1100 59 540 120 -

PSTY (b)' 500 84 52 5.8 -

PVC (b) 320 98 230 87 130 21

PVCZ (b) 650 79 470 20 370 30

REDO (a) 650 62 240 43

(b) 780 11 - -

RPU (b) 900 82 230 60 -

WOOL (a) — 280 90 —

(b) - - 160 19

*Mean of Average gas concentration (ppm) for each 30 minute exposure

Mass loading/chamber volume (mg/1)

(a) small furnace

(b) large furnace

112
TABLE 10

NBS Hydrogen Cyanide Production Per Unit Mass Loading*

Chamber Volume

Material Flaming Non-Flaming 440°C

Mean Std. Dev. Mean Std. Dev. Mean Std. Dev.

ppm_ PP-g, PPg

mg/1 mg/1 mg/1

ABS (b) 6.4 2.6 5.3 0.5 -

FPU (a+b) 0.6 0.2 0.4 0.2 -

MOD (a)

(b)

41 5.3 47 4.8

27 4.8

PVCZ (b) 7.6 1.0 13 2.2 13 0.8

RPU (b) 9.5 1.8 1.2 1.0 -

WOOL (a)

(b)

4.1 1.4 12 4.7

7.3

*Mean of Average gas concentration (ppm) for each 30 minute exposure

Mass loading/chamber volume (mg/1)

(a) small furnace

(b) large furnace

113
TABLE 11

Minimum Average Oxygen Concentrations

Material Percent Oxygen

Flaming Non-:flaming 440°C

a b a b a b

ABS 18.9 20.1

DFIR 17.8 16.3 19.9 19.2

FPU 17.4 14.2 19.3 19.9

MOD 18.7 18.5 20.3 19.9

PPS 17.7 19.7

PSTY 18.8 17.9 20.7 20.2

PVC 19.2 19.3 19.7

PVCZ 19.3 19.9 19.5

REDO 17.2 16.8 19.6

RPU 18.8 19.7

WOOL 16.2 17.5 19.3 19.8

a: NBS small furnace

b: NBS large furnace

114
Incapacitation

Times

After

Exposure

to

Non-Flaming

PVC co co

4-> 03

-(->

CJ

03Q.

03Uc

03>

<V Q . "O

s-03 -o o

O)VI

03 E

4-> CO+ 1 c:

03

a>

coCM

CO+ 1 03

UT>

*3-

CM+ 1 03

CO

CO

CO

r—

a

03 O)

=3 CO

4-> U

C

<C -r-E

LO LO o LOO o 1 LO CM

03 03 , CM , CO 1 CM CO i"- 00

lo o o o o I— LD CO «3- CM CO O CM — CO «3"

I— s_ 03 a> E 4=1 •r* E C 3 < ^

CM CO *3" LO CO CM CO <3- LO CO

CO

+J -I- c

CO 4-> *i

—O 0) 0! E 03 I— J- —* o

cn oCO oE• r~ T3

03O

S- 03

<u E

-Q

—«•

03 _E

C_3

03OCO

CO

si"

115

46:00
TABLE 13

Constants for Time-Concentration Hyperbolas (Y " Q + R/x)

Material Laboratory

Q

Flaming

R

Non-flaming

Q R Q

440 8 C R

ABS 1 3.2 188.0 -6.1 738.0 -13.8 1011.5

5 12.6 56.7 0.7 492.5 d

DFIR 1 13.3 231.4 12.8 226.9 H

2 5.0 389.2 17.7 99.0 H

3 7.2 265.8 7.5 107.0 H

6a 13.2 317.3 16.6 230.6 H

6b 13.8 246.2 18.5 98.7 H

8 9.3 230.3 10.3 242.7 H

FPU 6a , b -42.9 2739.0 G H

MOD 2 N.D. -7.7 161.3 N.D.

5 -2.3 79.8 -0.5 62.9 4.5 78.4

6 -2.8a 82.

9

a -18.

6

a 149.

9

a -3.4a ,b 157.4a,b

PPS 2 10.5 259.8 7.4 212.0 C

4 e 17.11 205.9 C

5 12.1 92.5 9.2 99.8 N.D.

PSTY 2 -25.3 1689.4 G H

6b -6.4 649.2 d H

PTFE i 6.5 27.0 4.9 16.7 d

PVC 3 e 2.8 161.4 C

PVCZ 1 -3.8 347.9 2.1 78.6 6.5 130.0

2 15.0 1.9 -51.7 888.9 d

REDO 5 9.2 441.5 16.8 172.5 H

6 12.

0

a ',b 385.

3

a,b <0

00 m 480.

0

a H

8 5.0 856.6 12.0 299.2 H

RPU 8 4.5 139.3 -3.9 940.6 G

WOOL 2 2.2 586.0 4.4 272.6 d

3 -10.9 517.0 e e

6 5.7

a 409.

9

a -12.

0

a 867.

9

a 11.2

b 332.

3

b

8 11.0 497.1 -9.5 891.1 -61.9 2595.9

a: NBS small furnace

b: NBS large furnace

C: No data points

d: One data point

e: Two data points

G: No incapacitation

N.D. Not determined

H: Non-flaming temperature within 50 8 C of 440°C

116
Material

ABS

DFIR

FPU

MOD

PPS

PSTY

PTFE

PVC

PVCZ

REDO

RPU

WOOL

*For

TABLE 14

EC 50Values ^ 9 in mg/£

La bora tory Flaming Non-flaming 440°C

1 10.6(7.4 - 1 5. 2)

c * ^21.0[15.1 1 - 25.2

12

] d ~20.2[15.1 1 - 25.

2

13

] 3 6.0(4. 1 - 8.9) 5. 8(2 .

8

- 8.4) 9. 0(4. 7 - 17.3)

5 ~17.0[15.07

- 20.

0

13

] —23 . 0[ 1 8 .

5

1 - 27.

5

13

] 07 /-l 3

< 37.6

1 20.0(16.4 - 24.3) 15.0(12.3 - 18.2) H

2 18.4(14.0 - 24.1) 10.1(7.2 - 14.2) H

3 ~14.5[10.01 - 19.

1

13

] 5.6(3. 1 - 9.9) H

4 N.D. 22.0(13.2 - 36.7) H

5 14.0(10.5 - 18.6) 19.2(14.3 - 25.8) H

6a 21.8(15.5 - 30. 7) 17 18.3(14.5 - 23.0) H

6 b ~23.5[23.01 - 24.

0

13

] 13.5(12.9 - 14.2) H 8 ~ 20.93,13 14.7(13.3 - 16.2) H

3 9. 6(4.1 - 22.1) 7. 0(3 .

6

- 13.6) H

4 ~49. 5 10 ’ 15 20.2(8.6 - 47.3) H

6a ,b 37.5(35.8 - 39.3) 53.0(40.1 - 69.9) H

2 N.D. 2. 7(2.1 - 3.4) N.D.

5 ~2.8[2.0] - 3.0

9+

] '-3.0[2.01 - 4.013] 5. 0[4.

0

1 - 6.013

] 6 3. 1(2. 2 - 4.3 ) a ’ 17

3. 2(2 .

8

- 3.7)

a 6 . 4(5 .

8

- 7.0) a,b

2 <15128 . 8 ( 6.

8

- 11 . 2 ) > 19.91

4 21.8(12.9 - 36.7) 19.0(10.2 - 35.3) N.D.

5 < 10

13

< 7.0

13

> 40.

O

1

2 ~ 30.

0

10

> 50.

O

1 H

6 b ~28.7[27.51 - 30.

4

13

] > 40.

O

1 H

1 ~0.80[0.063 - 1.514 13

] 0.68(0.31 - 1.49) —15. 2C1 5.

1

1 - 25.

2

13

] 6a > 0.25 1 > 5.03

1 N.D.

3 6 . 0(4.0 - 8.9) ~ 9 .4 10 ’ 16 13.5(4.9 - 36.8)

6 b —1 8 . 5[ 1 7 .

5

5

- 19.

8

13

] > 30.

O

5 > 30.

0

5

1 1 1 .8[1 0.1 8

- 15.

I

13

] ~ 5-4C5. 1

1 - 10 .

I

13

] 7.6(4. 5 - 12.7)

2 13.2(11.3 - 15.4) 11.7(10.3 - 13.2) <v 12 . 4^0*^

5 < 40.

6

13 1 3

< 25. 0

J H 6 34.8(31.1 - 39.0) a,b ’ *-, 23.0[22.

5

1 - 24.2

13

] 3 H 8 51.0(46.1 - 56.5) ^—24 .

1

3 * 1

3

H

8 8. 9(5.1 - 15.6) ~29.36 [29.3

] - 35.

1

13

] > 35.

2

1

2 23.8(16.0 - 35.3) ~17.0[15.05

- 20.

0

13

] > 27.

O

7

3 ^17.2[9.78

- 19.

0

13

] 6.8(4. 2 - 11.1) —23.3[19.34

- 30.

I

13

] 6 ~22.3[22.1 ] - 22.6

13

] a 19.7(16.2 - 24. 0)

a 24.5(23.0 - 26. 1

)

b

8 45.

0

13 24.0(20.3 - 28.3) ~ 29.3 6 [29.3

] - 35.

2

1

3

explanation of superscript letters and numbers, see legend to table 16.

117
TABLE 15

19 20 Slopes of EC &0 Concentration-Response Curves

Material Laboratory Flaming Non-flaming 440°C

ABS 1

3

5

DFIR 1

2

3

4

56a6b

8

FPU 346a, b

MOD 2

4

5

6

PPS 24

5

PSTY 26b

PTFE 16a

PVC 36b

PVCZ 1

2

REDO 56a ,b

8

RPU 8

WOOL 2

3

68

1.34(1.09 - 1.64)

1.63(1.02 - 2.59)

E

1.35(1.08 - 1.70)

1 .50(0.89 - 2.52)

EN.D. 1.43(1.07 - 1.91)

1.13(0.86 - 1 .48)

1

7

E

E

4.40(0.71 - 27.1)

E 1.07(1.04 - 1.11)

N.D. N.D.

E 1.25(0.69 - 2.28)

D 2.22(1.00 - 4.94)

D

E

E

E

C

1.65(1.24 - 2.20)

E

E 1.35(1.08 - 1.68)

D 1.30(1.11 - 1.52)

1 .10(0.94 - 1 .27)

2.18(0.28 - 17.21)

1.41(0.33 - 5.93)

E 2.00(1.15 - 3.47)

E

1 .58(1 .26 - 1.98)

1.41(1.16 - 2.29)

2.80(1 .09 - 7.18)

2.09(0.41 - 10.78)

1.68(1.12 - 2.52)

1.45(1.11 - 1.89)

1.09(1.01 - 1.17)

1.09(0.98 - 1.21)

2.76(1.26 - 6.03)

7.32(0.94 - 56.8)

1.73(1.07 - 2.79)

1.40(1.11 - 1.77)

N.D.

E 1.28(1.08 - 1.51)

1 .37(1 .03 - 1 .82)

2.59(1 .58 - 4.23)

D

C

C

3.31(0.59 - 18.71)

C

EC

E 1.28(1.01 - 1.61)

D

E

E

E

E 2.13(0.96 - 4.74)

1.35(1.08 - 1.69)

1.23(0.91 - 1.66)

E 2.71(0.78 - 9.38)

D

H

H

HH

H

H

H

H

H

H

H

N.D. N.D.

E 1.20(1.03 - 1.41)

CN.D.

C

H

H

EN.D.

5.90(0.29 - 120.59)

C

2.49(0.60 - 10.46)

E

H

H

H

C

C

E 1.10(1.05 - 1.16)

E

E

E

D

*For explanation of superscript numbers and letters, see legend to table 18.

118
TABLE 16

Material

ABS

DFIR

FPU

MOD

PPS

PSTY

PTFE

Laboratory

LC50 (30 minutes)

Flaming

19 Values in mg/

A

Non-flaming 440°C

1 17. 4(13. 9-21. 9)

C 22.0(17.6-27.5) 30.3(26.5-34.7)

3 15.6(13.2-18.4) >38.

0

1

>37.

9

1

5 20.8(18.9-22.9) 33.0(22.8-47.8) >37. 6

4

6b 22.1(20.0-24.4) >32.

5

1

N.D.

1 35.0(29.0-42.2) 21.7(19.7-23.9) H

2 50.1(43.1-58.3) 42.9(38.9-47.3) H

3 ^24.9[19.11-28.813

] d 37.3(26.7-51.9) H

4 30.6(28.4-33.0) 24.9(19.4-31.9) H

5 38.4(33.2-44.4) >46.

5

1

H

6a 45.0(38.5-52.6) 34.8(29.1-41.7) H

6b 39.8(38.2-41.4) 29.0(23.4-36.0) H

8 30.0(20.4-44.0) 20.5(15.8-26.6) H

3 >38.

0

1

>37.

9

1

H

4 >49.

5

1

>50.

9

1

H

6a, b >40.

0

5

>47.

7

5

H

2 N.D. 5. 2(4. 9-5.5) N.D.

4 7. 3(6. 6-8.1) 8.9(6.5-12.3) 10.4(7.1-15.3)

5 5. 0(3. 5-7.0) ^7.5[4.81 -10.

0

13

] ~5.6[4.01-6.0 9

] 6 5.0(4.2-5.9)

a 5.2(4.4-6.2) a 7.8(6. 9-8. 8 ) a,b

2 50.0(30.2-82.9) 18.7(15.7-22.3) >19.

9

1

4 ^39.6[24.91 -39.610

] 32.2(27.6-37.6) >9.9

1

5 15.2(13.4-17.2) 11.0(8.4-14.3) >40.

0

1

6b 20.0(16.8-23.8) 9.7(9.2-10.2) N.D.

2 53.5(41.8-68.5) >50.

0

1

H

4 33.0(30.9-35.2) >46.

2

1

N.D.

6b 38.9(37.9-39.9) >40.

0

1

H

1 1.01(0.33-3.13) 0.90(0.46-1.75) ^21. 9[5.1

1 -25.

2

9

] 4 2.60(1.15-5.89) >0.991

vL7.3[9.95-28.4 L3

6a >0.251 1 >5.025 1 N.D.

119
TAL,,,i, 16 (Continued)

Material Laboratory Flaming Non-flaming 440°C

PVC 3

• <• 6b

PVCZ 1

26b

REDO 5

6

8

RPU 46b

8

WOOL 2

3

6

8

>38.

I

1

>30.

0

1

13.4(10.9-16.5)

15.4(13.4-17.6)

15. 2(13. 5-17. I)

17

45.3(38.6-53.1)

59.0(54.5-63.9)

^65.0[60.33-72.3 13

]

>38.

4

1

14.3(13.4-15.3)

14.4(11.7-17.8)

>50.

0

1

^23.8[19.01 -28.613

] 40. 9(38. 1-43. 8) a

58.3(50.7-67.0)

>28.

5

1

>25.

0

5

9.6(7.3-12.7)

15.3(13.8-17.0)

>14.

0

8

40.0(35.8-44.7)

>45.

0

1

35.2(29.9-41.4)

>33.

9

1

>39.

6

1

45.1(37.9-53.6)

15.8(13.4-18.6)

29. 5(27. 8-31. 3) a

29.1(22.4-37.7)

>38.

2

1

>30.

0

1

'vl3.0[10.11-15.112

] >12.

4

1

13.9(13.2-14.6)

H

H

H

>39.

6

1

N.D.

>35.

2

1

>27.

1

~27.4 [19.3

1-30.111

] 35. 0(29. 0-42. 2)

b

%35.2[29.31 -35.2

2

]

a: NBS small furnace

b: NBS large furnace

c: (95% confidence limits)

d: Estimated EC or LC^q (values used to determine estimate)

H: 440°C is equal to or within 50°C of non-flaming temperatures

N.D. Not determined

1 0% affected

Superscripts 2-12 refer to number of animals af fected/number of animals tested

2 1/2

3 1/3

4 1/5

5 1/6

6 2/3

7 2/5

8 2/6

9 3/5

9+ 4/5

10 3/6

11 4/6

12 5/6

13 100% affected

14 No data points between 0% effect and 100% effect

15 One data point only

16 One data point between 0% effect and 100% effect

17 Significantly heterogeneous data

18 Late post-exposure deaths not counted

19 Litchfield, J.T. and Wilcoxon, F., reference 26.

120
TABLE 17

19

LC50 (30 minutes + 14 days) in mg/Jt (95% confidence limits)

Material Laboratory Flaming Non-flaming 440°C

ABS 1 15.0(12.3-18.3) 19.3(13.9-26.9) 30.0(26.5-34.0)

3 15.6(13.2-18.4) >38.

4

5

>38.

0

8

5 20.8(15.9-27.2) 33.3(23.1-47.9) >37. 6

4

6b 19.3(16.7-22.3) 30.9(21.2-45.0) N.D.

DFIR 1 35.8(28.6-44. 9)

18

16.7(14.5-19.3) H

2 45.3(39.0-52.7) 27.6(22.9-33.3) H

3 '\'24[19.0

i -29.0i2

] ib

26.8(21.3-33.7) H

4 29.6(22.7-38.6) 24.0(19.9-29.0) H

5 38.4(35.2-41.9) 25.9(20.0-33.5) H

6a 41.0(33.0-50.9) 20.4(16.4-25.3) H

6b 39.8(38.2-41.4) 22.8(20.2-25.8) H

8 29.8(23.9-37.1) 18.5(17.3-19.8) H

FPU 3 >38.

0

1

27.8(16.9-45.8) H

4 >49.

5

1

40.0(31.2-51.3) H

6a&b >40.

0

5

26. 6(15. 3-46. 2)

17

H

MOD 2 N.D. 5. 2(4. 9-5. 5) N.D.

4 7. 1(6. 4-7. 9) 7.8(6. 3-9.7) 10.0(6.9-14.4)

5 4. 7(3. 2-6. 9) 7. 0(5. 0-9. 7) ^5.7[4i-69

] ib

6 4.4(3.9-5.0)

a 5.3(4.0-7.1) a 7.3(6.3-8.5)

a *

PPS 2 25.3(22.0-29.2) 18.7(15.2-23.0) >19.

9

1

4 %36[24.91-39.611

] 16

32.2(27.7-37.5) >9.89 1

5 11.7(9.1-15.0) 10.7(8.4-13.6) >40.

0

1

6b 19.8(14.8-26.5) 9.5(9.1-10.1) N.D.

PSTY 2 53.5(41.4-69.1) >50.

0

1

H

4 32.6(30.5-34.8) >46.

2

1

N.D.

6 b 38.9(37.9-39.9) >40.

0

1

H

121
TABLE 17 (Continued)

Material Laboratory Flaming Non- flaming 440°C

PTFE 1 0.164(0.073-0.367) 0.125(0.083-0.188) ^15[5.01 -25.013

] 14

4 0.400(0.02-6.81) 0.235(0.05-1.20) N.D.

6a 0.045(0.039-0.054) 0.045(0.017-0.120) N.D.

PVC 3 ^[io1-^12

] 16 M.6[14

8 -1913

] 16 20.7(14.0-30.7)

6b 17.3(14.8-20.2) 20.0(14.7-27.2) 25.0(20.2-31.0)

PVCZ 1 9.4(7.2-12.3) 7.6(5.5-10.5) 8.5(6.1-11.9)

2 14.3(12.5-16.3) 13.3(11.5-15.4) >12.

4

4

6b '^15[15.0

1 -15.513

] 11.3(8.5-14.9) 12.8(12.1-13.6)

REDO 5 45.0(39. 9-50.8) 25.0(18.7-35.5) H

6 56. 8(51. 6-62. 5)

a,b

30. 3(26. 0-35. 4) a H

8 60.0(56.6-63.6) 35.0(24.5-50.1) H

RPU 4 >38.

4

1 >34.

0

1

>39.

6

1

6b 13.3(12.2-14.5) >39.

6

1

N.D.

8 11.3(7.6-16.8) >35.

I

2

>35.

2

1

WOOL 2 42.8(36.6-50.1) 25.2(18.4-34.6) >27.

2

1

3 ^[lg1 -24 13

] 14 15.8(13.5-18.6) ^[W1 -3011

] 16

6 28. 2(23. 0-34. 5) a25. 1(22. 3-28. 3) a

32. 1(30. 2-34. l)

b

8 60.0(46.6-77.3) 28.5(23.5-34.6) 32.6(28.7-37.0)

*For explanation of superscript numbers and letters, see legend to Table 16.

122
TABLE 18

Slopes of LC

sn , 30 Minutes,

19 20

(95% confidence limits of slope) *

Material Laboratory Flaming Non-flaming 440°C

ABS 1 1.63(1.36 - 1.96) 1.41(1.12 - 1.77) 1.18(1.05 -

3 1.23(1.08 - 1.39) C C

5 1.14(1.11 - 1.18) 2.08(0.85 - 5.10) C

6b 1.24(1.11 - 1.37) C N.D.

DFIR 1 1.39(1.08 - 1.79) 1.17(1.08 - 1.26) H

2 1.25(1.01 - 1.55) 1.17(1.06 - 1.30) H

3 E 1.66(0.76 - 3.61) H

4 1.16(1.08 - 1.25) 2.01(1.19 - 3.40) H

5 1.29(1.11 - 1.50) C H

6a 1.48(0.99 - 2.21) 1.43(1.06 - 1.93) H

' 6b 1.05(1.02 - 1.08) 1.39(0.71 - 2.72) H

8 1.83(0.19 - 17.54) 1.54(0.74 - 3.19) H

FPU 3 C C H

4 C C H

6a,

b

C C • H

MOD 2 N.D. 1.11(1.01 - 1.21) N.D.

4 1.18(1.00 - 1.38) 1.62(1.13 - 2.33) 1.80(1.01 -

5 1.76(1.24 - 2.51) E E

6 1.49(0.99 - 2. 25) a 1.25(1.09 - 1.44)

a 1.23(1.01 - PPS 2 2.58(0.39 - 16.97) 1.30(1.05 - 1.61) C

4 E 1.21(0.97 - 1.51) C

5 1.19(1.09 - 1.30) 1.45(1.06 - 1.97) C

6b 1.24(0.88 - 1.75) 1.09(1.04 - 1.14) N.D.

PSTY 2 1.41(0.84 - 2.38) C H

4 1.12(1.06 - 1.19) C N.D.

6b 1.03(1.00 - 1.07) C H

PTFE 1 14.10(1.61 - 123.62) 4.76(2.17 - 10.42) E

4 2.06(1.25 - 3.40) C E

6a C G N.D.

1.33)

3.21)

1.51) a,b

123
TABLE 18. (Continued)

C

C

E

C

1.08(1.02 - 1.14)

H

H

H

C

N.D.

C

C

E

1.40(0.82 - 2.3'.)

E

a:

b:

C:

D:

E:

H:

N.D.

17:

19:

20:

NBS small furnace

NBS large furnace

No slope as EC,-q or LC^q > highest concentration tested

No slope as EC-,. or LC^ < lowest concentration tested

3U jU

EC^q or LC,-q estimated

440°C is equal to or within 50°C of non-flaming temperature

Not determined

Significantly heterogeneous data

Litchfield and Wilcoxon - reference 26.

Units are

% effect (incapacitation or lethality)

PVC 3 C C

6b C C

PVCZ 1 1.51(1.31 - 1.72) 1.51(1.08 - 2.12)

2 1.29(1.09 - 1.53) 1.14(0.99 - 1.30)

6b 1.10(0.91 - 1.35) C

REDO 5 1.41(0.99 - 2.01) 1.22(1.08 - 1.39)

6 1.17(1.08 - 1.27) C

8 E 1.33(0.98 - 1.80)

RPU 4 C C

6b 1.11(1.06 - 1.16) C

8 1.38(0.97 - 1.97) C

WOOL 2 C 1.19(1.02 - 1.40)

3 E 1.23(1.10 - 1.37)

6 1.13(0.98 - 1.30) 1.09(1.04 - 1.15)

8 1.33(1.09 - 1.63) 1.66(0.46 - 6.00)

124
TABLE 19

Material

Slopes of LC^q

Laboratory

, 30 min. + 14 days

Flaming

(95% confidence limits

Non-flaming

of slope)"^

440°C

ABS 1 1.58(1.34-1.85) 1.80(1.02-3.16) 1.20(1.07-1.36)

3 1.23(1.08-1.40) C C

5 1.46(1.13-1.89) 2.06(0.86-4.92) C

6b 1.37(1.09-1.72) 1.23(0.99-1.54) N.D.

DFIR 1 1.41(1.06-1.89) 1.38(1.05-1.81) H

2 1.30(1.00-1.69) 1.26(1.04-1.53) H

3 E 1.64(0.0-3.85) H

4 1.69(0.66-4.30) 1.69(1.29-2.22) H

5 1.14(1.01-1.28) 1.73(1.25-2.41) H

6a 1.66(0.81-3.39) 1.43(1.09-1.88) H

- 6b 1.05(1.02-1.08) 1.25(1.10-1.42) H

8 1.51(0.61-3.73) 1.08(1.04-1.12) H

FPU 3 C 1.87(1.19-2.94) H

4 C 2.37(1.46-3.84) H

6a&6b C 2. 37 (0.93-6. 01)

17

H

MOD 2 N.D. 1.11(1.02-1.21) N.D.

4 1.14(1.00-1.30) 1.40(1.18-1.66) 1.91(1.04-3.52)

5 1.88(1.22-2.89) 1.70(1.23-2.36) E

6 1.30(1. 10-1. 53) a 1.67(0. 99-2. 81) a 1.35(1.09-1.68)

PPS 2 1.23(1.09-1.38) 1.35(1.02-1.78) C

4 E 1.21(0.98-1.49) C

5 1.41(1.00-2.00) 1.31(1.07-1.61) C

6b 1.50(0.50-4.47) 1.07(1.04-1.11) N.D.

PSTY 2 1.51(0.71-3.20) C H

4 1.14(1.07-1.23) C N.D.

6b 1.03(1.00-1.07) C H

125
TABLE 19 (Continued)

Material Laboratory Flaming

PTFE 1 4.15(1.67-10.28)

4 5. 10(1. 80-14. 43)

17

6a 1.33(0.98-1.81)

PVC 3 E

6b 1.22(1.12-1.34)

PVCZ 1 1.51(1.19-1.91)

2 1.24(1.08-1.43)

6b E

REDO 5 1.30(1.00-1.70)

6a 1.15(1.07-1.24)

8 1.07(1.03-1.11)

RPU 4 C

6b 1.10(0.95-1.28)

8 1.83(0.15-21.68)

WOOL 2 1.39(0.97-1.99)

3 E

6 1.60(0. 91-2. 83)

a

8 1.86(0.83-4.14)

Non-flaming 440°C

2.07(1.29-3.31) E

5. 27(0. 79-35. 17)

17

N.D.

7.94(1.28-49.31) N.D.

E 1.63(1.18-2.26)

1.47(1.03-2.09) 1.36(0.90-2.06)

1.88(1.04-3.41) 1.52(1.19-1.93)

1.30(1.07-1.58) C

1.42(0.65-3.1) 1.09(1.01-1.17)

1.78(0.69-4.62) H

1.32(1.06-1.65) H

2.29(0.49-10.69) H

C C

C N.D.

C C

1.62(0.89-2.95) C

1.22(1.10-1.36) E

1.17(1. 06-1. 29)

a 1.39(0. 82-2. 36)

b

1.47(0.89-2.41) 1.15(0.87-1.52)

For explanation of superscript numbers and letters, see legend to table 18.
TABLE 20

Comparison of NBS ECg

0

and LC

5Q

Values

Material Mode

EC

50

30 min.

(mg/i

)

LC

50

30 min. + 14 days

(mg/1)

LC

50

30 min.

(mg/1)

ABS F ND 19.3(16.7 - 22.3) 31 .5(24.7 - 40.2)

NF ND 30.9(21.2 - 45.0) >32.

5

1

DFIR-a F 21.8(15.5 - 30. 7)

17 41.0(33.0 - 50.9) 45.0(38.5 - 52.6)

NF 18.3(14.5 - 23.0) 20.4(16.4 - 25.3) 34.8(29.1 - 41.7)

DFIR-b F ~23.5[23.0 1 -24.013

] 39.8(38.2 - 41.4) 39.8(38.2 - 41.4)

NF 13.5(12.9 - 14.2) 22.8(20.2 - 25.8) 29.0(23.4 - 36.0)

FPU F 37.5(35.8 - 39.3) >405 >405

NF 53.0(40.1 - 69.9) 26.6(15.3 - 46. 2)

17 >47.

7

5

MOD F 3. 1(2. 2 - 4.3)

17

4. 4(3. 9 - 5.0) 5. 0(4. 2 - 5.9) NF 3. 2(2. 8 - 3.7) 5. 3(4.0 - 7.1) 5. 2(4. 4 - 6.2)

440 6. 4(5. 8 - 7.0) 7. 3(6. 3 - 8.5) 7. 8(6. 9 - 8.8)

PPS F ND 19.8(14.8 - 26.5) 20.0(16.8 - 23.8)

NF ND 9. 5(9.1 - 10.1) 9. 7(9. 2 - 10.2)

PSTY F ~28.7[27.5] -30.413

] 38.9(37.9 - 39.9) 38.9(37.9 - 39.9)

NF >40] >40] >40]

PTFE F > 0 . 251

1 0.045(0.039 - 0.054) >0.251 1

NF >5.025] 0.045(0.017 - 0.120) >5.025]

PVC F ~18.5[17.5 5 -19.8 13

] 17.3(14.8 - 20.2) >30.

0

1

NF >30.

O

5 20.0(14.7 - 27.2) >25.

O

5

440 >30.

O

5 25.0(20.2 - 31.0) >30.

0

1

PVCZ F ND ^15.0[15.01 -15.513

3 15.2(13.5 - 17.1)

NF ND 11.3(8.5 - 14.9) >14.

0

8

440 ND 12.8(12.1 - 13.6) 13.9(13.2 - 14.6)

REDO F 34.8(31.1 - 39.0) 56.8(51.6 - 62.5) 59.0(54.5 - 63.9)

NF ~23.0[22.5 1 -24.2 13

] 30.3(26.0 - 35.4) >45 ]

RPU F ND 13.3(12.2 - 14.5) 14.3(13.4 - 15.3) NF ND >39.

6

1 >39.

6

1

WOOL F ~22.3[22.1 - 22.

6

13

] 28.2(23.0 - 34.5) 40.9(38.1 - 43.8)

NF 19.7(16.2 - 24.0) 25.1(22.3 - 28.3) 29.5(27.8 - 31.3)

440 24.5(23.0 - 26.1) 32.1(30.2 - 34.1) 35.0(29.0 - 42.2)

*For explanation of superscript numbers and letters, see legend to table 16.

17

127
TABLE 21

Comparison of the Normalized Flaming LC,-q and EC,-q Data from all Laboratories

Material LCj-q Material LC^q Material EC^q Material

LC

50

DFIR LC

50

DFIR EC

50

DFIR

(30 min. + 14 days) (30 min.

)

(30 min.)

REDO 1.53 + 0.43

a

(3)

b

1.58 + 0.52(3) 1.99 + 0.64(2)

FPU - - 1.16 + 0.70(2)

WOOL 1.15 + 0.59(4) 1.27 + 0.58(3) 1.17 + 0.14(3)

PSTY 1.09 + 0.10(3) 1.04 + 0.06(3) 1.43 + 0.29(2)

DFIR 1.00(8) 1.00(8) 1.00(7)

PPS 0.64 + 0.40(4) 0.79 + 0.42(4) -

PVC 0.53 + 0.13(2) - 0.60 + 0.26(2)

ABS 0.53 + 0.10(4) 0.56 + 0.05(4) 0.72 + 0.43(3)

RPU 0.36 + 0.03(2) 0.42 + 0.09(2) 0.43(1)

PVCZ 0.32 + 0.06(3) 0.36 + 0.04(3) 0.65 + 0.09(2)

MOD 0.16 + 0.07(3) 0.16 + 0.07(3) 0.17 + 0.04(2)

PTFE 0.006 + 0.006(3) 0.057 + 0.040(2) 0.04(1)

a: Mean + standard deviation calculated from values that

were normalized to Douglas fir.

b: Number of data sets used to calculate mean.

It is important to note that the results shown in tables 21, 22, and

23 pertain to the particular samples tested during this study. The

materials used were selected to represent a wide range of properties.

No attempt was made to provide statistically valid samples of a given

material. Therefore the results should not be used to judge any

particular class of material.

128
TABLE 22

Comparison of the Normalized Non-flaming LC^q and EC^q Data from all Laboratories

Material LC^q Material LC cn Material

5U EC^q Material

LC cn DFIR

50

LC

50

DFIR EC

50

DFIR

(30 min. + 14 days) (30 min.) (30 min.)

RPU - - 1.99(1)

REDO 1.45 + 0.46a

(3)

b

1.72(1) 1.45 + 0.27(2)

FPU 1.31 + 0.32(3) - 1.83 + 1.31(3)

ABS 1.27 + 0.10(3) 1.01(1) 1.21 + 0.18(3)

WOOL 1.07 + 0.41(4) 0.94 + 0.42(4) 1.40 + 0.30(4)

DFIR 1.00(8) 1.00(7) 1.00(8)

PVC 0.74 + 0.20(2) - 1.68(1)

PPS 0.71 + 0.44(4) 0.69 + 0.53(3) 0.87 + 0.01(2)

PVCZ 0.48 + 0.02(3) 0.40 + 0.06(2) 0.76 + 0.56(2)

MOD 0.26 + 0.06(4) 0.21 + 0.13(3) 0.20 + 0.06(3)

PTFE 0.006 + 0.004(3) 0.04(1) 0.045(1)

a: Mean + standard deviation calculated from values that were

normalized to Douglas fir.

b: Number of data sets used to calculate mean.

It is important to note that the results shown in tables 21, 22, and

23 pertain to the particular samples tested during this study. The

materials used were selected to represent a wide range of properties.

No attempt was made to provide statistically valid samples of a given

material. Therefore the results should not be used to judge any

particular class of material.

129
TABLE 23

Comparison of the Normalized LC^ and EC<.q Data at 440°C from All Laboratories

Material LC^q Material LCj-q Material EC,-q Material

LC

50

DFIR

(30 min. + 14 days)

LC

50

DFIR

(30 min.

)

EC

50

DFIR

(30 min.)

ABS 1.80

a

(l)

b

1.40(1) 1.48 + 0.18(2)

REDO 1.45 + 0.46(3) 1.72(1) 1.45 + 0.27(2)

WOOL 1.37 + 0.42(3) 1.22 + 0.49(3) 2.66 + 1.31(3)

DFIR 1.00(8) 1.00(7) 1.00(8)

PVC 0.93 + 0.23(2) - 2.41(1)

PTFE 0.90(1) 0.85 + 0.22(2) 1.01(1)

PVCZ 0.54 + 0.04(2) 0.54 + 0.08(2) 0.87 + 0.51(2)

MOD 0.32 + 0.10(3) 0.33 + 0.12(2) 0.33 + 0.10(2)

a: Mean + standard deviation calculated from values that were normalized

to Douglas fir.

b: Number of data sets used to calculate mean.

It is important to note that the results shown in tables 21, 22, and

23 pertain to the particular samples tested during this study. The

materials used were selected to represent a wide range of properties.

No attempt was made to provide statistically valid samples of a given

material. Therefore the results should not be used to judge any

particular class of material.

130
Percent

Death

«3-

C\J

C

Q

<=t

oo

<1>

CD

4-> 3

OO

CO

E Q- 3 CL in E VO O CO cr> CO

i— * CO in o 0"i X z «3 C_> CO 00 1 CO

s; =c

l/> CO ,

CT> in 00

-Q CD • • • • • • in -c: i vo <3* CM CM O Crt O -r- 3Z

CM CM

oo

• >> C flD •<- X)

E <=3- o i—

• CL C X

•r- O) 0 +J

1

00o

d.

E

o

c:o

fO

-»-> +-> C -i- a) u O fD

S- CL

a> «

Q_ U

Q-^—

E o

<D O

CD -Oo

oo o o o oo

oCM

I"- COl"- coI"- CD

CO oLO CO

o

o oo o o oo

o oinco o

*3-

LD

CM

CO

in

r«* in

ocd

5-

CD

ro

rvj

I o o>CL

131
TABLE 25

NBS Carboxyhemoglobin and Gas Concentration Values at

LCj-q (30 min + 14 days) - Flaming Combustion

Material Deaths

Auto

Ignition

Temp(°C)

LC

50

+

(mg/£)

COHb

(%)

CO

(ppm)

HCN

(ppm)

PPS W,P 650 19.8 82 3500 —

DFIR b W 465 39.8 83 3400 -

DFIR a w 465 41.0 84 3000 -

REDO w 480 56.8 83 2800 -

PVCZ W,P 675 VL5.0 a.68 ^2200 VL10

RPU w 550 13.3 61 1700 130

ABS w 575 19.3 42 1500 130

PSTY w 490 38.9 78 1300 -

PVC p 600 17.3 49 1100 -

FPU w 370 >40 >65 >960 >22

WOOL W,P 650 28.2 43 700 130

MOD W,P 725 4.4 22 400 180

a: NBS small furnace

b: NBS large furnace

W: Within exposure

P: Post-exposure

t: For 95% confidence limits, see Table 17, laboratory 6

132
TABLE 26

NBS Carboxyhemoglobin and Gas Concentration Values at

(30 min + 14 days) -Non-Flaming Combustion

Material Deaths

Auto

Ignition

Temp (°C)

LC

50

+

(mg/ i,) COHb

(%)

CO

(ppm)

HCN

(PPP*)

PPS W 650 9.5 84 4400 -

DFIR b W,P 465 22.8 81 2700 -

REDO P 480 30.3 80 2400 -

DFIR a P 465 20.4 80 2100 -

RPU * 550 >39.6 >47 >1700 >44

PVCZ P 675 11.3 36 1200 150

WOOL W,P 650 25.1 41 920 240

FPU P 370 26.6 54 820 10

ABS P 575 30.9 27 670 160

PVC P 600 20.0 27 590 -

MOD w 725 5.3 16 430 250

PSTY * 490 >40.0 >6 >72

*No deaths in range studied.

a: NBS small furnace

b: NBS large furnace

W: Within exposure

P: Post-exposure

t: For 95% confidence limits, see Table 17, laboratory 6

133
NBS-114A (REV. 9-78)

U.S. DEPT. OF COMM.

BIBLIOGRAPHIC DATA

SHEET

1. PUBLICATION OR R

nORT NO.

NBSIR 82-2532

%. RzciQteniH Ace^sslon No,

4. TITLE AND SUBTITLE

Further Development of a Test Method for the Assessment

of the Acute Inhalation Toxicity of Combustion Products

5. Publication Date June 1982

L'' V" ' v

t :-.-S v 7. AUTHOR(S)

Barbara C. Levin, Andrew J. Fowell, Merritt M. Birky,

Maya Paabo, Alan Stolte, Dolores Malek

8. Performing Organ. Report No.

9. PERFORMING ORGANIZATION NAME AND ADDRESS

NATIONAL BUREAU OF STANDARDS

DEPARTMENT OF COMMERCE

WASHINGTON, DC 20234

11. Contract/Grant No.

12. SPONSORING ORGANIZATION NAME AND COMPLETE ADDRESS (Street, city. State, ZIP) 13. Type of Report & Period Covered

15. SUPPLEMENTARY NOTES

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

16. ABSTRACT (A 200-word or less factual summary of most s i gni ficant information. If document includes a si gnificant bibliography or

literature survey, mention it here.) This report describes the development of a test method for the assessment of

acute inhalation toxicity of combustion products of materials. The procedure is

primarily intended for research and screening purposes. It provides: 1) a method

for determining, under flaming and non-flaming conditions, the LC^q (the

concentration of combustion products which causes 50% lethality in the test

animals (rats) exposed for 30 minutes and observed for 14 days following

exposure) ; 2) an optional procedure to examine materials which rapidly produce

combustion products which cause death of test animals within a 10 minute

exposure and a 14 day post-exposure observation period; and 3) a description

of analytical and physiological measurements which can provide more detailed

information on the nature of the toxic effects of combustion products.

Limitations of the test method are identified and future work to address them

is proposed.

The participation through the direct exchange of technical information of

organizations representing academia, industry, and other agencies of the United

States Government is acknowledged.

17. KEY WORDS (six to twelve entries; alphabetical order; capi tahze only the first letter of the first key word unless a proper name

separa ted by semicolons)

combustion products; flaming combustion; inhalation; materials; non-flaming

combustion; test method; toxicity.

18. AVAILABILITY f xJ Unlimited 19. SECURITY CLASS

(THIS REPORT)

21. NO. OF

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20. SECURITY CLASS

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22. Price

Order From National Technical Information Service (NTIS), Springfield, V A. 22161 UNCLASSIFIED

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