r OF COMMERCE

Standards

NBS Special Publication 749

Fire Hazard Comparison of

Fire-Retarded and

Non-Fire-Retarded Products

Vytenis Babrauskas, Richard H. Harris, Jr., Richard G. Gann, Barbara C. Levin,

Billy T. Lee, Richard D. Peacock, Maya Paabo, William Twilley,

Margaret F. Yoklavich, and Helene M. Clark

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m he National Bureau of Standards1 was established by an act of Congress on March 3, 1901. The

m Bureau's overall goal is to strengthen and advance the Nation's science and technology and facilitate their

effective application for public benefit. To this end, the Bureau conducts research to assure international competitiveness and leadership of U.S. industry, science and technology. NBS work involves development and transfer of

measurements, standards and related science and technology, in support of continually improving U.S. productivity,

product quality and reliability, innovation and underlying science and engineering. The Bureau's technical work is performed by the National Measurement Laboratory, the National Engineering Laboratory, the Institute for Computer Sciences and Technology, and the Institute for Materials Science and Engineering.

The National Measurement Laboratory

Provides the national system of physical and chemical measurement;

coordinates the system with measurement systems of other nations

and furnishes essential services leading to accurate and uniform

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research; develops, produces, and distributes Standard Reference

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2Some divisions within the center are located at Boulder, CO 80303.

3 Located at Boulder, CO, with some elements at Gaithersburg, MD.
RESEARCH INFORMATION CENTER

National Institute of

Standards and Technology

Ga i thersburg i MD 2089?

ttbSL

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4?

NBS Special Publication 749

Fire Hazard Comparison of

Fire-Retarded and

Non-Fire-Retarded Products

Vytenis Babrauskas, Richard H. Harris, Jr., Richard G. Gann, Barbara C. Levin, Billy T. Lee,

Richard D. Peacock, Maya Paabo, William Twilley, Margaret F. Yoklavich, and Helene M. Clark

Fire Measurement and Research Division

Center for Fire Research

National Bureau of Standards

Gaithersburg, MD 20899

Sponsored by:

Fire Retardant Chemicals Association

Lancaster, PA 17604

July 1988

U.S. Department of Commerce

C. William Verity, Secretary

National Bureau of Standards

Ernest Ambler, Director
Library of Congress

Catalog Card Number: 88-600560

National Bureau of Standards

Special Publication 749

Natl. Bur. Stand. (U.S.),

92 pages (July 1988)

CODEN: XNBSAV

U.S. Government Printing Office

Washington: 1988

For sale by the Superintendent

of Documents,

U.S. Government Printing Office,

Washington, DC 20402
Table of Contents

Acknowledgements and Sponsorship

List of Figures vii

List of Tables ix

Executive Summary xi

v

1 INTRODUCTION 1

£. MATERIALS 3

EXPERIMENTAL 7

3.1 Cone Calorimeter 7

3J.i Combustion Techniques 1

3.1.2 Gas Sampling Through Impingers 1

3.1.3 Test Conditions 8

3.1.4 Data Collected 8

5.7.5 Test Results 9

3.2 Furniture Calorimeter 10

3.2.1 Experimental Technique— General 10

3.2.2 Experimental Technique— Specific Details 11 3.2.3 Gas Sampling Through Impingers 11 3.2.4 Furniture Calorimeter Results 12

3.2.5 Direct Comparison to Cone Calorimeter Results 12

3.2.6 Use of Predictive Small-Scale/Large-Scale Correlations 13

3.3 Small-Scale Toxicity Tests 14

3.3.1 Animals 14

3.3.2 Small-Scale Toxicity Test System 14

3.3.3 Gas Analysis 15

3.3.4 N-Gas Model Prediction 15 3.3.5 Results and Discussion of the Small-Scale Toxicity Tests 16

1 MODEL SIMULATIONS OF THE LARGE-SCALE ROOM/CORRIDOR/ROOM FIRES 35

4.1 Product Arrangement A and Room Corridor Configuration A 35

4.1.1 NFR Products 35

4.1.2 FR Products with Auxiliary Burner 35

4.1.3 Model Predictions for Configuration A 36

4.2 Product Arrangement B and Room/Corridor Configuration B 36

iii
iv Table of Contents

4.3 Worst Case Scenario for Product Arrangement B and Room/Corridor Configuration B 36

4.3.1 NFR Products 36

4.3.2 FR Products 37

4.3.3 Model Predictions With Configuration B 37

4.4 Use of the Model Predictions in the Design of Large-Scale Tests 38

S. LARGE-SCALE TESTS

5.1 Experimental 49

5.1.1 Room/Corridor/Room Configuration 49

5.1.2 Room Fire Test Arrangement 49

5.1.3 Instrumentation 50

5.2 Test Procedure 51

5.3 Large-Scale Test Results 52

5.3.1 Data from Exhaust Stack Instruments 52

5.3.2 Data from Animal Chambers 52

5.3.3 Data from Other Observations 53

5.4 Comparison Between Small-Scale and Large-Scale Toxicity Findings 53

5.4.1 Species Yields 53

5.4.2 Fraction of Toxicity Accounted by CO 54

5.4.3 Combustion Products of Extreme Toxic Potency 55

5.4.4 Combustion Products of Unusual Toxic Potency 55

5.5 Comparison Between Computer Model Predictions and Actual Large-Scale Results 55

§. ASSESSMENT OF HAZARD

6.1 Times to Untenability 69

6.2 Amounts of Combustion Products 70

7. SUMMARY

7.1 Properties of Individual Products Tested 73

7.2 Results from Large-scale Evaluations of NFR- and FR-Furnished Rooms 74

7.3 Relations Between Measurements in Different Test Methods 75

8L CONCLUSION

Appendix A. Ion Chromatography Procedure 79

Appendix B. Gas Chromatography Procedure 81

Appendix C. Log of Large-Scale Test Observations 83

References 85
Acknowledgements and Sponsorship

J. Newton Breese, Phyllis Martin, and Carmen

Davis provided valuable assistance in the large-scale

aspects of the testing program.

The study was sponsored by the Fire Retardant

Chemicals Association, P.O. Box 3535, Lancaster, PA

17604. The work was under the auspices of FRCA's

Hazard Assessment Committee, comprised of the fol- lowing firms contributing financial and consultative

support:

Albright and Wilson Americas, Inc. ALCOA

Ameribrom, Inc.

Anzon, Inc. Asarco, Inc. BorgWarner Chemicals Inc. Chemical Industrial Association Ltd.

Dow Chemical USA

Ethyl Corporation

Ferro Corporation

Great Lakes Chemical Co.

Laurel Industries, Inc. M & T Chemicals Inc. McGean-Rohco Inc. Occidental Chemical Co.

Solem Industries, Inc.

v

List of Figures

Figure 1. TV cabinets used in the tests 4

Figure 2. Business machine housings used in the tests 4

Figure 3. Upholstered chair cushions used in the tests 5

Figure 4. Pieces of the cables used in the tests 5

Figure 5. Pieces of the circuit boards used in the tests 5

Figure 6. Conceptual view of the Cone Calorimeter 25

Figure 7. Smoke measurement system used on the Cone Calorimeter. 25

Figure 8. Impinger gas sampling in the Cone Calorimeter. 26

Figure 9. Furniture Calorimeter test of business machines and TV cabinets 26

Figure 10. Furniture Calorimeter test of chairs 26

Figure 11. Furniture Calorimeter test of cables (Z-configuration) 27

Figure 12. Furniture Calorimeter test of cables (vertical array) 27

Figure 13. Furniture Calorimeter test of circuit boards 28

Figure 14. Impinger gas sampling in the Furniture Calorimeter 28

Figure 15. Rate of heat release for TV cabinets measured in the Furniture Calorimeter. 29

Figure 16. Rate of heat release for business machine housings measured in the Furniture Calorimeter. 29

Figure 17. Rate of heat release for upholstered chairs measured in the Furniture Calorimeter. 30

Figure 18. Rate of heat release for cables measured in the Furniture Calorimeter 30

Figure 19. Rate of heat release for circuit boards measured in the Furniture Calorimeter. 31

Figure 20. Schematic of gas analysis system used in the small-scale toxicity test 31

Figure 21. Impinger gas sampling in the small-scale toxicity test 32

Figure 22. Comparison of materials by their EC50 , LCS0 (30 min.) and LC50 (30 min. + 14 days)

after flaming decomposition 32

Figure 23. Animal weight change following a 30 minute exposure to the flaming decomposition

products from a mass loading of 20 mg/1 of specimen K 33

Figure 24. Arrangement A of test items in the burn room 38

Figure 25. Plan view of large-scale test arrangement A 38

Figure 26. Mass loss rate for NFR furnishing arrangement A and room-corridor configuration A

without the auxiliary burner 39

Figure 27. Composite mass loss history for NFR furnishings 39

Figure 28. Mass loss rate for FR furnishing arrangement A and room-corridor configuration A

with the auxiliary burner .40

Figure 29. Plan view of large-scale test arrangement B 40

Figure 30. Arrangement B of test items in the burn room 41

Figure 31. Mass loss rate for NFR furnishing arrangement B and room-corridor configuration B

without auxiliary burner 41

Figure 32. Accelerated mass loss rate for NFR furnishing arrangement B and room-corridor

configuration B without the auxiliary burner 42

vii
viii List of Figures

Figure 33. Accelerated mass loss rate for NFR furnishing arrangement B and room-corridor

configuration B with the auxiliary burner 42

Figure 34. Mass loss rate for FR furnishing arrangement B and room-corridor configuration B

without the auxiliary burner. 43

Figure 35. Mass loss rate for FR furnishing arrangement B and room-corridor configuration B

with the auxiliary burner. 43

Figure 36. Model prediction and test result curves for the average upper layer temperature in the

burn room/corridor/target room for NFR furnishings without the auxiliary burner 44

Figure 37. Model prediction and test result curves for carbon monoxide in the burn room/corridor/

target room for NFR furnishings without the auxiliary burner. 44

Figure 38. Model prediction and test result curves for the average upper layer temperature in the

burn room/corridor/target room for NFR furnishings with the auxiliary burner 45

Figure 39. Model prediction and test result curves for carbon monoxide in the burn room/corridor/

target room for NFR furnishings with the auxiliary burner. 45

Figure 40. Model prediction and test result curves for average upper layer temperature in the

burn room/corridor/target room for FR furnishings without the auxiliary burner. 46

Figure 41. Model prediction and test result curves for carbon monoxide in the burn room/corridor/

target room for FR furnishings without the auxiliary burner 46

Figure 42. Model prediction and test result curves for the average upper layer temperature in the

burn room/corridor/target room for FR furnishings with the auxiliary burner 47

Figure 43. Model prediction and test result curves for carbon monoxide in the burn room/corridor/

target room for FR furnishings with the auxiliary burner 47

Figure 44. Impinger gas sampling in the large-scale burn room 64

Figure 45. Impinger gas sampling in the large-scale animal chamber 64

Figure 46. Heat release rates in the large-scale room/corridor/room tests without the auxiliary burner 65

Figure 47. Heat release rates in the large-scale room/corridor/room tests with the auxiliary burner 65

Figure 48. Mass flow rates of CO in the large-scale room/corridor/room tests without the

auxiliary burner 66

Figure 49. Mass flow rate of CO in the large-scale room/corridor/room tests with the auxiliary burner. ... .66

Figure 50. Mass flow rate of C02 in the large-scale room/corridor/room tests without the

auxiliary burner 67

Figure 51. Mass flow rate of C02 in the large-scale room/corridor/room tests with the auxiliary burner. . . .67

Figure 52. Smoke flow rates in the large-scale room/corridor/room tests without the auxiliary burner 68

Figure 53. Smoke flow rates in the large-scale room/corridor/room tests with the auxiliary burner. 68
List of Tables

Table 1 Cone Calorimeter Data Summary— 30 kW/m2 Irradiance Tests 18

Table 2 Cone Calorimeter Data Summary—Test Average Data at 30 kW/m2 Irradiance 19

Table 3 Cone Calorimeter Data Summary— 100 kW/m2 Irradiance Tests 19

Table 4 Cone Calorimeter Data Summary-Test Average Data at 100 kW/m2 Irradiance 20

Table 5 Irradiance Threshold Limit for Foam S with Nylon Fabric Cover 20

Table 6 Summary of Furniture Calorimeter Test Conditions 21

Table 7 Summary of Furniture Calorimeter Results 21

Table 8 Comparison of Cone Calorimeter Versus Furniture Calorimeter Data 22

Table 9 N-gas Model Toxicity Procedure 22

Table 10 Chemical and Toxicological Results from Materials Decomposed in the Flaming Mode 23

Table 11 Summary of LC50 Values and 4-Gas Model Prediction Values Determined in the

Small-Scale Toxicity Tests 24

Table 12 Dimensions of Room/Corridor/Room Large-Scale Test Facility 56

Table 13 Construction of Large-Scale Test Facility 56

Table 14 Location of Instrumentation 56

Table 15 Ratio of Gases in Animal Chambers to Target Room for Specified Times 57

Table 16 Animal Exposure Chamber Filling Times and Estimated CO When Closed 58

Table 17 Chemical and Toxicological Results in Animal Exposure Chambers Filled During

Large-Scale Room Burns 59

Table 18 Comparison of Peak Times and Concentration Areas for CO, HC1, HBr and HCN in

Large-Scale Tests (Burn Room) 59

Table 19 Specimen Mass Consumed in Large-Scale Tests 60

Table 20 Comparison Between Yields of Toxic Species in the Different Devices 60

Table 21 Fraction of Total Toxicity Accounted for by CO (NBS Combustion Toxicity Test) 61

Table 22 Fraction of Total Toxicity Accounted for by CO (Large-Scale) 61

Table 23 Times to Reach Untenable Conditions in Large-Scale Tests 62

Table 24 Comparison of Total Heat Release from Large-Scale Fires with Furniture Calorimeter

and Cone Calorimeter Calculated Values 62

Table 25 Comparison of Smoke from Large-Scale Fires with Furniture Calorimeter and Cone

Calorimeter Calculated Values 62

Table 26 Comparison of Average CO from Large-Scale Fires with Furniture Calorimeter, Cone

Calorimeter, and Toxicity Test Calculated Values 63

Table 27 Total Toxicity Results in Large-Scale Tests 63

ix

Executive Summary

BACKGROUND

Fire retardants (FR) are most frequently added to plastics in order to reduce their burning rate. Historically, this has meant increasing a material's resistance

to a variety of Bunsen burner type exposures. These

simple, visual tests have resulted in the modification of

many of the most obviously flammable materials, and

an accordant increase in fire safety.

In recent years, the public has perceived a broader

concept of product fire safety. This advanced view includes three contributions to fire hazard:

• Rate of fire growth. This is measured as the

rate of heat release from the burning material

and the resulting increased temperatures near and away from the fire. • Smoke obscuration. The time-variant yield of

soot and the nature of that soot affect both the

spread of alarm and the ability of alerted people to escape.

• Smoke toxicity. Inhalation of the fire products can result in a variety of ill effects ranging

from disorientation to death.

This new understanding has led to reconsideration

of the overall fire safety of commercial building and

furnishing materials. For fire-retardant products in

particular, the question has been raised as to (a)

whether the additives effect a trade-off between

decreased burning and increased emission of toxic gas

species (smoke) and (b) whether there is a net safety

benefit from the use of fire retardants.

During the past several years, the National Bureau

of Standards' Center for Fire Research (NBS-CFR)

has been developing the methodology to determine the

overall fire hazard of commercial products. This includes the use of advanced bench-scale measurement

methods, computer modeling of fires, and confirmatory large-scale tests.

The Fire Retardant Chemicals Association (FRCA)

therefore asked NBS-CFR to investigate the fire hazard of a wide array of fire-retardant (FR) containing products relative to non fire-retarded (NFR), but

otherwise substantially identical, products. The two

central issues to be explored were:

(1) For today's most commonly used FR/polymer

systems, is the overall fire hazard reduced, when

compared to similar non-fire retarded (NFR)

items?

(2) Since both the commercially popular FR chemicals and the base polymer formulations can be ex- pected to change in the future, can appropriate

bench-scale test methodologies be validated

which would allow future testing to be quick and

simple?

APPROACH

To answer these questions, a wide-ranging ex- perimental program was formulated. Five representatives of commonly used plastic products were especially manufactured (using commercial formulations)

for this program, each in an NFR and a FR version.

These were:

• polystyrene television cabinet

• polyphenylene oxide business machine housing

• polyurethane foam-padded upholstered chair

• electrical cable with polyethylene wire insulation and rubber jacketing

• polyester/glass electric circuit board

The test program involved bench-scale tests of the

individual products in the Cone Calorimeter, where

rate of heat release (the best quantitative measure of

burning rate), ignitability, rate of smoke production,

and the rates of production of various toxic combustion gases were determined. Bench-scale tests were

also conducted on each product using the NBS cup

xi
Executive Summary

furnace combustion toxicity apparatus. Entire articles were then tested in the Furniture Calorimeter, which

allows measurements similar to those taken in the

Cone Calorimeter, but at full-scale and burning in an open environment. The final proof testing took place

in a large-scale burn room/corridor/target room facility, where instead of examining the specimens singly, an arrangement which included either all the NFR or

all the FR products was used.

Before this final testing could be done, assurance was obtained that a useful fire scenario had been developed. For the first time, computer fire modeling was used to determine that the NFR room had enough

combustibles to assure a rapid, high intensity fire, and

that the concentration and flow of the combustion

gases were such that useful toxicological quantification by means of a bioassay (animal exposure) could

be done. It was also important to assure that, in the FR

case, the fire would not simply die out because the initial item ignited failed to spread flame. (Such an out- come would not provide assurance that, had the ignition source been just slightly bigger, the fire would

have spread and much more hazardous conditions

resulted.)

THE LARGE-SCALE RESULTS

The impact of FR materials on the survivability of

the building occupants was assessed in two ways: (1) Comparing the time to untenability in the burn room;

this is applicable to the occupants of the burn room.

(2) Comparing the total production of heat, toxic

gases, and smoke from the fire; this is applicable to occupants of the building remote from the room of fire origin.

The time to untenability is judged by the time that is available to the occupants before the earlier of (a)

room flashover, or (b) untenability due to toxic gas

production occurs. For the FR tests, the average

available escape time was more than 15-fold greater

than for the occupants of the NFR room. With regard

to the production of combustion products,

• The amount of material consumed in the fire for the FR tests was less than half the amount

lost in the NFR tests. • The FR tests indicated an amount of heat

released from the fire which was 1/4 that

released by the NFR .tests. • The total quantities of toxic gases produced in

the room fire tests, expressed in "CO equivalents," were 1/3 for the FR products, compared

to the NFR ones.

• The production of smoke was not significantly

different between the room fire tests using

NFR products and those with FR products.

Thus, in these tests, the fire retardant additives did

decrease the overall fire hazard of their host products.

The above conclusions are specifically pertinent

only to the materials actually examined. Thus, while it has been demonstrated that very significantly en- hanced fire performance can be obtained with fire- retarded products, such improvements are by no means to be automatically expected from all fire- retarded products. Instead, it will still be necessary to

test and evaluate proposed new systems individually.

However, these tests do show that the proper selection

of fire retardants can markedly improve the fire safety

of specific products.

THE RESULTS OF SMALLER-SCALE TESTS

Prediction of room fire behavior from smaller-scale

test data is a relatively recent area of fire research. A

full capability requires that both the burning rate (heat

release rate or mass loss rate) and the relevant yields

of combustion products could be predicted. Attempts

to calculate burning rates are a new area of endeavor;

and there are a number of physical phenomena which

cannot be adequately represented by the smaller-scale

test itself, but must be addressed using special data

analysis techniques or by empirical correction factors.

Without such detailed techniques in hand, it was

still desired to find out if the Cone Calorimeter rate of

heat release measurements of products could indicate

the level of real-scale improvement which the FR additives could effect. This was found to be true for 4 of

the 5 product categories tested. The Cone Calorimeter

results for the electric cables did not show adequate

correlation.

Small-scale toxicity tests were used by themselves to answer two questions:

• Do the combustion products from the specimens, when burned under flaming conditions,

show extreme toxicity? • Could the animal mortality be predicted from

the analyses of the concentrations of the principal toxic fire gases and knowledge of their

toxicological interactions? (That is, is there no

unusual toxicity?)

The results showed that none of the test specimens

produced smoke of extreme toxicity. The smoke from

both the FR and the NFR products was similar in potency and comparable to the potency of smoke produced by materials commonly found in buildings. For
Executive Summary

7 out of the 10 specimens studied, the results can be

predicted from the 4-gas model; the 3 exceptions are

the FR polystyrene TV cabinet, the FR ethylene vinyl

acetate wire insulation, and the FR polyester circuit

board. For those three cases, unidentified agents made

a small contribution to the specimen's toxicity. Identification of these agents was not pursued because they were minor.

The large-scale studies generally confirmed the

small-scale toxicity results. Although the uncertainties were larger and individual products were not isolated

in large-scale testing, the large-scale data do show that

neither extreme nor unusual toxicity was found.

It was further found that the fraction of total toxicity

accounted for by CO in the small-scale toxicity test and the fraction measured in the large-scale room/corridor/room tests were similar. This encourages the use

of the NBS combustion toxicity test to characterize the

gross toxicity of combustion gases.

The gas species yields at both scales were also compared directly. C02 and the acid gas (HC1, HBr,

HCN) yields showed agreement in all cases where

their concentrations were well above the background.

For CO, there was substantive disagreement, with the

NBS combustion toxicity apparatus and, especially,

the Cone Calorimeter giving some values which were

substantially lower than those observed in the Furniture Calorimeter. The values derived from large-scale

tests were, in turn, not very well predicted by the Furniture Calorimeter data, even though the scale was

similar.

In all cases, the ratios between the smoke yields for

the NFR and the FR products were close in the Cone

Calorimeter and in the Furniture Calorimeter. However, the ratio between the numerical values in the

Furniture Calorimeter and those in the Cone

Calorimeter was typically 1:2. The exception to this

enhanced smoke yield in the smaller-scale test came

from the polystyrene TV cabinets. There, both the

NFR and the FR versions showed greater smoke

yields in the Furniture Calorimeter than in the Cone

Calorimeter.

Thus, the answer to the second major question

Can bench-scale test methodologies suffice for evaluating future products?— is mixed. In some cases, the

smaller-scale tests provide indicative data; in others,

they do not. This finding is consistent with the current

development of predictive methods for the Cone

Calorimeter or the Furniture Calorimeter on a

product-class basis. It remains for the rapidlyprogressing fire hazard modeling to provide a more

universal relationship between bench-scale measure- ments of fire properties and the fire threats from commercial products.

1

Introduction

Fire retardants are most frequently added to plasics in order to reduce their burning rate. Historically, this has meant increasing a material's resistance

to a variety of Bunsen burner type exposures. These

simple, visual tests have resulted in the modification

of many of the most obviously flammable materials,

and an accordant increase in fire safety. In recent years, the public has perceived a broader

concept of product fire safety. This advanced view includes three contributions to fire hazard:

• Rate of fire growth. This is measured as the

rate of heat release from the burning material

and the resulting increased temperatures near and away from the fire. • Smoke obscuration. The time-variant yield of

soot and the nature of that soot affect both the

spread of alarm and the ability of alerted people to escape.

• Smoke toxicity. Inhalation of the fire products can result in a variety of ill effects ranging

from disorientation to death.

This new understanding has led to reconsideration

of the overall fire safety of commercial building and

furnishing materials. For fire-retardant products in

particular, the question has been raised as to (a)

whether the additives effect a trade-off between

decreased burning and increased emission of toxic gas

species (smoke) and (b) whether there is a net safety

benefit from the use of fire retardant.

During the past several years, the National Bureau

of Standards' Center for Fire Research (NBS-CFR)

has been developing the methodology to determine

the overall fire hazard of commercial products. [Fire

hazard refers to the level of threat presented by a fire to people and structures. For example, the fire hazard

to the sleeping occupants of a wooden shack from an

indoor usage of gasoline for heating purposes might

be high: no one would escape and the entire structure

would be destroyed. Fire risk, by contrast, weighs the

possible hazards by the likelihood they will occur. Thus, the risk from the fire above might be quite low

because such a situation is rare.] The assessment of

fire hazard involves the use of advanced bench-scale

measurement methods, computer modeling of fires

and their impact, and confirmatory large-scale tests. The Fire Retardant Chemicals Association (FRCA)

therefore asked NBS-CFR to investigate the fire hazard of a wide array of fire-retardant (FR) containing products relative to non fire-retarded (NFR), but

otherwise similar, products. The central question to be

explored was: Can these FR products be considered to provide a higher all-around degree of fire safety than

their NFR counterparts? This is the first time that such

a global test would be applied to such a wide range of

products.

Five types of products were selected, each chosen to represent the potential use of a different type of

polymer and a different FR formulation. In each case, an NFR control was prepared, similar to the FR product, but containing no FR agent. The commodities were to be studied using the following:

• Cone Calorimeter

• Furniture Calorimeter

• Small-Scale N-Gas Model Toxicity Procedure

• Fire hazard modeling (FAST)

• Multi-room large-scale fire tests

In the Cone Calorimeter [1],* bench-scale specimens cut from the test products were evaluated for

several fire properties: effective heat of combustion,

and rates of heat release, smoke, and several different

gas species production. In the Furniture Calorimeter

Numbers in brackets refer to literature references listed in Section

9 at the end of this report.

1
2 INTRODUCTION

[2], real-scale specimens were tested for the same

variables. In the Small-Scale N-Gas Model Toxicity Procedure

[3,4], the smoke from each burning product was evaluated for its toxic potency and any unusual toxic gas

generation using a modified animal-exposure methodology.

These small-scale data were then combined as needed and used as input to FAST, the fire growth and

smoke transport program in the prototype version of

HAZARD-I [5]. The resulting predictions of fire development were used to guide the design of the multiroom tests. Finally, in large-scale fire experiments, all of the

specimens (either NFR or FR) were grouped and

burned to determine heat release rate, smoke, toxic

gas production, and actual animal toxicity. These tests served as the ultimate demonstration of actual

differences between the fire hazard performance of the

NFR and the FR products.

Before proceeding to the detailed description of the

study, two items of clarification are in order. First,

when discussing products of combustion, we will distinguish between production and yield. Production is the total amount of a substance evolved during the

duration of a test; yield is that production normalized

by the mass of specimen lost (burned) during the

period. Results from disparate test devices are most

properly compared on a yield basis, while hazard

assessment usually requires knowledge of the production involved.

Second is the definition of similar or different

results. The individual test measurements to be presented typically have good repeatabilities, on the order

of 10% or better. Therefore, the assessment of similarity is simply a matter of comparing the differences in

values with the uncertainties in their measurements.

By contrast, a single scenario will be developed for

large-scale testing, and the results will be compared in

the context of that scenario. The scenario chosen,

while well-grounded, can by no means be unique. In- deed, a different scenario choice could seriously influence the conclusions in a manner that can not be determined in this work.
Materials

Five different types of products were evaluated in

this study. Each was characterized with and

without appropriate fire retardants. Fire-retardant

product formulations were chosen to represent ones which are commercially available and in common

use, but which were also anticipated to represent high

quality performance. The items studied were as follows:

(1) TV Cabinet housing. The TV cabinets were

moldings of an external cabinet only; no internal

working parts were used. The average thickness of

the molded material was 3.0 mm. The assembled

cabinets are shown in Figure 1. Sample H (NFR)—high impact polystyrene base

formulation;

Sample G (FR)— the same base formulation

with decabromodiphenyl oxide (12% by weight)

and antimony oxide (4%)

(2) Business machine housing. The business machine

housings were also moldings of an external cabinet only and were of similar physical appearance

as the TV cabinet housings; again, no internal

working parts were used. The average thickness of

the molded material was 3.0 mm. The assembled

housings are shown in Figure 2.

Sample F (NF/?)— poly(2,6-dimethyl 1,4 phenylene) oxide; also includes polystyrene, polybutadiene, polyethylene, mineral oil, and stabilizer

additives.

Sample A (FR)— the same base formulation,

with a triaryl phosphate ester based flameretardant (to give 1% P by weight).

(3) Upholstered chairs. The upholstered chairs were

constructed of only two combustible materials:

flexible polyurethane padding foam, and a cover

fabric. Instead of a conventional frame, the chairs

used a steel mock-up frame. The assembled chairs are shown in Figure 3. Sample T (NFR)-The density of this foam was

25 kg/m3

. Sample S (FT?) —This foam contained an organic

chlorinated phosphate, and organic brominated

retardant and 35% alumina trihydrate. The loadings represented an elemental content of 4.75%

Br, 2.6% CI, 0.32% P, and 10.0% Al. The density

of this foam was 64 kg/m3. The same nylon fabric (250 kg/m2

) was used as a cover for both samples. Since the cover fabric was not varied, it was not evaluated in certain of

the bench-scale tests.

(4) Cable array. Each electric cable contained five

copper wires, each 14 AWG (1.63 mm dia.). The

outside diameter of each insulated wire was 3.30

mm. The overall, outside diameter of the complete jacketed cable was 12.7 mm. Pieces of the

cable approximately 250 mm long are shown in

Figure 4.

Sample D (NFR) —wire insulation made of

crosslinked ethylene vinyl acetate copolymer,

with clay (18.9 parts per 100 resin), antioxidant (2

parts), processing aid (1 part), and catalyst (1.5

parts). Covered with a black outside jacket made

of chlorosulfonated polyethylene containing

Sb203 . Elemental contents were 12.2% CI and

2% Sb.

Sample K (FR)— wire insulation made of

polyethylene cross-linked with ethylene vinyl acetate, with clay (28 parts), chlorinated

cycloaliphatic fire retardant (38 parts), Sb2 03 (18.9 parts), antioxidant (2 parts), processing aid

(1 part), and catalyst (1.5 parts). Outside jacket

identical to that for the NFR specimen.

The outer jackets, being the same in both in3
4 MATERIALS

stances, were not evaluated in detail in certain of

the bench-scale tests.

(5) Laminated circuit board This material was intended to be representative of glass/polyester electric circuit boards. It contained, however, no copper traces and no electrical components. The

thickness of the board was 6.4 mm, and it was

supplied in large sheets, which were cut up for use. Pieces of each circuit board are shown in

Figure 5.

Sample C (NFR)- polyester resin (38% by

weight), with CaC03 filler (44% by weight), and

fiberglass reinforcement (18%).

Sample L (FR) -polyester resin (39%), with

decabromodiphenyl oxide (10%), Sb203 (3%),

A1203 -3H2 0 (30%), and fiberglass reinforcement

(18%).

Figure 1. TV cabinets used in the tests.

?1S

Figure 2. Business machine housings used in the tests.
Figure 5. Pieces of the circuit boards used in the tests.

Experimental

3.1 CONE CALORIMETER

3.1.1 COMBUSTION TECHNIQUES

The Cone Calorimeter (Figure 6) was initially presented in 1982 as an improved technique for

measuring rate of heat release on bench-scale specimens [1]. Its operation involves an application of the

oxygen consumption principle. Earlier instruments

for measuring rates of heat release were based on

either a concept of a well-insulated box, which led to some very serious measurement errors, or on substitution type schemes, which were cumbersome and

difficult to operate.

The oxygen consumption principle [7] states that

for most combustibles there is a unique constant, 13.1

MJ/kg 02 , relating the amount of heat released during

a combustion reaction and the amount of oxygen con- sumed from the air. Thus, using this principle it is only necessary to measure the concentration of oxygen in the combustion stream, along with the flow

rate. In the Cone Calorimeter, specimens of a material or product to be tested are cut into a 100 mm by 100 mm

size. The thickness depends on the type of product

tested, and can range from 6 to 50 mm. The specimen

edges are protected from burning, and the specimen

can be oriented either horizontally or vertically. In the

FRCA program, all specimens were tested horizontally, face up.

The specimen is heated by an electric heater in the

shape of a truncated cone, hence, the name Cone

Calorimeter. The irradiance to the specimen can be

set to any desired value from zero to 110 kW/m2

. If

required, external ignition of the specimen is provided by an electric spark. Since a uniform, controlled irradiance is provided, the ignition times themselves, as measured, constitute a suitable test for

ignitability.

The specimen is mounted on a load cell and its mass, along with all other instrument data, is re- orded every 5 s. A few years ago, when shortcomings of existing

smoke measuring tests were becoming evident, a smoke measuring system (Figure 7) was evolved for

the Cone Calorimeter. This comprises a He-Ne laser

beam projected across the exhaust duct. The monochromatic light is monitored by a solid-state detector.

A second detector serves as a reference, to guard

against effects of drift and of laser power fluctuations.

The optical system is designed to be self-purging, and

does not use optical windows. Further details of the

smoke measuring system have been given in a recent

publication [8].

An overview of the design features, along with the

specifications and limitations of the Cone Calorimeter

has recently been published [9].

3.1.2 GAS SAMPLING THROUGH IMPINGERS

Since the Cone Calorimeter represents a wellcontrolled combustion environment to which specimens can be exposed, it became advantageous to also use it for the measurement of gaseous species yields.

Thus, fixed gas analyzers for 02 , CO, C02 , total hydrocarbons, and H2 0 vapor have been implemented. For the testing of FRCA materials, however,

it was also necessary to characterize the yields of certain acid gases -HC1, HBr, and HCN. For these,

commercial on-line gas analyzers were not available,

thus a batch sampling technique needed to be

employed.

A portion of the gaseous products and soot in the

main exhaust duct of the Cone Calorimeter was col7
8 EXPERIMENTAL

lected by replacing the soot collection filter with a gas

sampling apparatus. Figure 8 shows a diagram of the

gas sampling apparatus. The gaseous products were

collected in tared 250 ml glass impinger bottles containing approximately 125 ml of 5 mM KOH. To maximize the collection efficiency, two impingers were

used in series, separated by a 45 mm diameter PTFE

filter (0.45 fim nominal porosity) to collect the sample

from the exhaust stream. The second impinger served

to trap any gases that might break through the PTFE

filter. Because only a small amount of breakthrough was detected, the second impinger was not used later

in the program. The flow of gases through the impingers was controlled by the existing mass flow controller used for soot collection. The ratio of gases collected to gases exhausted was nominally 1:1000;

however, the exact value for each test was recorded

and used in computations. Sample collection started

when the specimen was placed on the load cell of the

calorimeter; the collection was stopped when the

specimen stopped burning and no more smoke was being evolved.

After the tests were completed, the impingers were

weighed and the contents transferred to plastic containers. Prior to analysis, the filter containing the soot was placed into the solution in the first impinger. The

pH of the unknown solutions was determined to make

sure that it did not drop below the optimum range for

the ion chromatographic analysis. The samples were

then analyzed for the expected anion(s) by the procedure described in Appendix A.

3.1.3 TEST CONDITIONS

The tests were conducted according to the ASTM

(American Society for Testing and Materials) method

P 190 [10]. In addition, besides specifying the specimen orientation (horizontal, face-up), and the use of

spark ignition, to describe fully the test conditions re- quires specifying the test irradiance and any special

specimen preparation techniques.

Three different irradiance values were used in the

test program:

• 10 kW/m2 (with spark ignition) • 30 kW/m2 (with spark ignition) • 100 kW/m2 (without spark ignition)

The lowest irradiance value, 10 kW/m2

, would not

be expected to cause ignition in most specimens; specimens which are unusually ignition-prone would,

however, be ignited. The intermediate value, 30

kW/m2

, represents a heating value that can readily be

imposed by one free-burning item on another. Many

bench-scale tests also impose heating levels in the

range of 30 kW/m2 on test specimens. The high value,

100 kW/m2

, was selected to monitor if any unusual

combustion phenomena become manifest at high irradiances, which are not evident during normal testing.

Such high irradiances are typical of the upper ranges

of heating values imposed on materials in a fully involved (flashed over) room fire. All specimens, as the final step of specimen preparation, were wrapped in aluminum foil on the bottom

and sides. Otherwise, the TV cabinet housings, the

business machine housings and the circuit board specimens were prepared by cutting 100 mm by 100 mm

coupons from the full-scale articles supplied, and

were not otherwise treated. The upholstered chair

specimens were prepared by cutting foam specimens

slightly smaller than 100 mm by 100 mm by 50 mm

thick. The cover fabric was cut into 200 mm by 200

mm samples, and from each corner a 50 mm by 50

mm square was removed. The foam was then covered

with the fabric over its top and 4 sides. The fabric was

stapled to the foam along the bottom edge of all sides.

Since the FR product, in this case, was an inner,

rather than outer, layer, the furniture foam samples were also tested alone, without the use of the cover

fabric. The test cables were prepared by cutting them

into 100 mm lengths and laying up a single row, sideby-side, in the aluminum foil. Two supplementary

configurations on the cables were also tested, where

(1) the outer rubber jacket was removed, and only the

individual wires (copper + wire insulation) were

tested, and (2) the outer rubber jacket alone was

tested.

The specimen thicknesses, as tested, were:

• TV cabinet housing— 3 mm

• Business machine housing— 3 mm

• Upholstered chair- 50 mm

• Cable array -13 mm

• Laminated circuit board -6 mm

The thicknesses of the TV cabinet and business

machine housings were thinner than the normal test thickness of 6 mm. For such cases, the test method

prescribes that the specimen should be tested in conjunction with its end-use substrate. Since, in the present test series, the exact arrangement of the electronic

equipment in the TV cabinet and business machine

housings could not be stated, a back face condition

comprising only the normal refractory fiber blanket was used.

3.1.4 DATA COLLECTED

The data to be derived from the bench-scale tests in

the Cone Calorimeter constitute a very large set, and
Cone Calorimeter 9

can be analyzed in a multitude of ways. The most important variables which are presented include the fol- lowing:

• peak rate of heat release (kW/m2

) • rates of heat release averaged over various time

periods, starting with the time of ignition

(kW/m2

) • effective heat of combustion (MJ/kg). This will

be less than the oxygen-bomb value of the heat

of combustion, since the combustion is incomplete.

• percent specimen mass lost (%)

• time to ignition (s) • average smoke obscuration (m2 /kg). Smoke

production from a material has the rational

units of m2

, representing the extinction cross- section of the smoke. This is normalized by

the amount of specimen mass lost (kg). • average yields of each of the measured gas

species (kg/kg)

The total number of replicate tests run varied between two and six, with the higher number generally

being run on specimens showing wider data scatter.

3.1.5 TEST RESULTS

The Cone Calorimeter results are summarized in

Tables 1 through 5. For the 10 kW/m2 irradiance, even though the spark ignitor was used, none of the test specimens ignited. Therefore, detailed data at 10

kW/m2 are not tabulated and will not be further discussed. Detailed data sets (Tables 1 to 4) were collected at 30 kW/m2 and at 100 kW/m2

. The values re- ported, unless otherwise noted, are the average of two

to six tests. Measures of data uncertainty are given in

Tables 1 and 2. The discussion below focuses mainly

on the 30 kW/m2 results; where the findings at 100

kW/m2 are substantively different, the 100 kW/m2 data

will also be discussed.

At this point, only the raw data from the bench-scale

Cone Calorimeter tests are first presented. Thus, the

reader is cautioned that differences in performance

noted among the specimens refer only to the benchscale performance. The comparison to large-scale

findings, and discussions of the general usefulness of

bench-scale methods for predicting large-scale fire results are topics taken up in the subsequent sections

of this report. (See Sections 7 and 8.)

3.1.5.1 TV cabinet housings

For the TV cabinet housings, specimens H and G

showed roughly similar fractions of mass burned. The

peak rate of heat release of the FR specimen G was

only 35 % of the value for the un-retarded specimen H.

This is a significant improvement. Specimen G only

released half as much total heat as did H, while its effective heat of combustion was some 2.5 times

smaller. The ignition time of the FR specimen, however, was somewhat shorter than for the NFR one. The

smoke yield per unit mass loss of specimen, however, was about twice for the FR specimen as for the NFR

one. The yield of CO was about 7-fold greater for the

FR specimen, compared to the NFR one, at 30 kW/m2

irradiance. However, since at 100 kW/m2 the yields of

CO became essentially the same, no special significance is attributed to the finding. The C02 yield for

the FR specimen was some 3 times less than for the

NFR one under either irradiance condition. Since the

amount of Br in specimen G was known, it was also

possible to compute the recovery of Br for this specimen, which was 71%.

3.1.5.2 Business Machine Housings

For the business machine housings, the FR specimen A showed a slightly longer time to ignition and a

slightly lower percent of mass burned. The peak rate of heat release was reduced by some 40% from the unretarded specimen F. The FR specimen also showed

total heat released of some 1/3 lower, with a 30%

decrease in the effective heat of combustion. In other

words, the mass loss rates for the two specimens were

similar, with the lower rate of heat release (RHR) of

specimen A being accounted mainly by the lowered

heat of combustion (Ahc ). The CO yield rate was

about 50% higher for the FR specimen, while the

smoke values were essentially identical. There were no qualitative differences in any measured variables

between the 30 and the 100 kW/m2 test conditions.

3.1.5.3 Upholstered Chairs

For the fully-composite specimens of the upholstered chairs, the FR specimen S took more than twice

as long to ignite as the NFR specimen T, and lost a smaller fraction of its mass. The peak rate of heat

release was decreased by some 40%, while the total heat released was unchanged and the heat of combustion decreased by about 35%. CO and HCN yields were more than doubled for the FR specimen, compared to the NFR one, while the smoke yield was essentially unchanged. C02 yields for the NFR specimens were about half of those for the FR ones. There were no significant differences between the results at the two test irradiances used.

When tested without the cover fabric, the heat and

mass loss values were roughly similar to those for the
10 EXPERIMENTAL

composite specimens, with the advantages of the FR

material seen a bit more clearly in some cases. The ignition time for the FR material was 12.5 times longer

than for the NFR material. Smoke production, however, was substantially lower for both T and S under

the conditions of no cover fabric, suggesting that the

fabric's performance here will dominate the results for

the composite. HCN yield was similar for the un- covered T as for the covered one, but the FR version,

specimen S, did not show the sizeable increase over

the NFR one, as was seen in the composites testing.

As already reported [11], this again suggests that small,

detailed changes of polyurethane fire exposure can make significant changes in the yields of HCN from

polyurethane foams.

Since the amount of CI in specimen S was known, it was possible to compute the recovery of CI, which was 84%.

For the subsequent large-scale fire tests, it was also

necessary to determine the minimum irradiance nec- essary to cause ignition of the FR polyurethane

foam/nylon fabric assembly. These data were obtained

in the Cone Calorimeter and are shown in Table 5. The

results show that 11 kW/m2 is the approximate

threshold of ignition for sample S.

3.1.5.4 Cable Arrays

For the cable arrays, when the fully composite specimens were tested, little difference was seen between

the specimens when tested at 30 kW/m2 irradiance. At

100 kW/m2 irradiance, however, the FR specimen

showed the same peak rate of heat release as it did at 30 kW/m2 irradiance (which is an unusual occurrence). The NFR specimen D behaved more typically

in that its rate of heat release at the higher flux was

substantially higher than at the lower flux.

Since the amounts of Br and CI in specimen D were known, recovery fractions could be computed; these were 27% for Br and 105% for CI. The CI result can be considered to be approximately 100% , to within ex- perimental uncertainty. The exact halogen content for

specimen K was not known.

When the wire specimens alone were tested, however, the FR specimen K showed only about 40% of

the heat release rate of the NFR specimen D. Ignition

times and mass burnecf remained essentially identical,

while the total heat released and the heat of combustion dropped to half. Smoke yields increased by some

40%, while the CO yield increased by some 4-1/2

times. The results at 100 kW/m2 irradiance were not

substantially different from the values at the lower

heating flux.

The jacketing materials, when tested alone, did not

show differences between D and K. This was as expected, since the formulation of the jacketing material was identical for both specimens.

3.1.5.5 Circuit Boards

For the circuit board materials, the FR specimen L

showed a peak rate of heat release that was less than

that for the NFR specimen C by a factor of 2.5. The

ignition time showed a 50% improvement, while the

total heat release and the effective Ahc were also both

decreased. Smoke production for the FR specimen was slightly less, while the CO production was

substantially higher. At the higher, 100 kW/m2 heating

flux, the main substantive difference was a near- doubling of the smoke production propensity shown

by the NFR specimen; by contrast, irradiance changes

did not affect smoke production for the FR specimen.

3.2 FURNITURE CALORIMETER

With the above bench-scale data in hand, it is tempting to make extrapolations to large-scale behavior.

The tools for doing so, for most products, are as yet

unavailable. Thus, it was necessary to also study the

same test articles in a large-scale configuration. These

large-scale data can then, validly, be used as input into

predicting the behavior of a room fire. In those few

cases where methods for predicting large-scale behavior based on bench-scale data are available, direct

comparisons between large-scale predictions, based on the bench-scale data and the actual, measured

large-scale Furniture Calorimeter data can be compared.

3.2.1 EXPERIMENTAL TECHNIQUE—GENERAL

The NBS Furniture Calorimeter has been developed

as a technique for easily measuring the rates of heat

release of free-standing combustibles, burning in

open-air conditions [2]. As with the Cone Calorimeter, the design of the apparatus is based on using oxygen consumption as the measuring principle. Since it

is intended to measure the burning of large objects

which can sustain their own burning, once suitably ignited, no external radiant heat is provided. (By contrast, in the Cone Calorimeter, where small-scale

specimens are measured, external radiation is necessary in order to represent the effects on the specimen

of adjacent items or portions of the item burning.)

Similar to the Cone Calorimeter, the Furniture

Calorimeter also contains a load cell, a laser photometer for measuring smoke, and gas analysis equipment. The Furniture Calorimeter currently exists at NBS in two versions, a low-capacity version (for fires not much over 1000 kW) and a high-capacity version
Furniture Calorimeter 11

(for up to about 7000 kW). The low-capacity version was used in this study. The ignition source, except as

specified otherwise, is typically a natural gas burner,

having a nominal 180 x 150 mm face and operated at the 50 kW level for 200 s. Those conditions approximate the fire behavior of a small, trash-filled plastic

wastebasket [12].

Demonstration tests have shown that under certain

conditions the open-air large-scale measurements

made in the Furniture Calorimeter can be directly

transferred to the room-fire situation [13]. The limits

of this relationship have not been fully tested, however. In the present program one of the objectives was

to be able to compare the success of this type of prediction.

A summary of the test specimens evaluated with the

NBS Furniture Calorimeter and their test conditions

are given in Table 6. A description of the test set-up

and procedure used for testing each item is given

below. Schematics of the test arrangements are given

in Figures 9-13. The test results are summarized in

Table 7.

3.2.2 EXPERIMENTAL TECHNIQUE—SPECIFIC

DETAILS

With the exception of the cable tests 19-21, each of

the test specimens was burned under the Furniture

Calorimeter using the standard burner described

above. Cable tests 19-21 used a 0.36 m long line

burner to administer the same flow of natural gas.

Each of the simulated business machine and television cabinets was made by assembling one from two

molded half-sections, forming a single closed cabinet

with an opening at one end. The overall size of the

cabinet was 0.36 X 0.33 x 0.25 m high, and the

opening was closed with a galvanized steel cover. No

internal working parts were used in the cabinets. In

each test, two cabinets, separated with a 25 mm spacing, were placed over the test platform with the burner

positioned 0.30 m directly under the spacing between

cabinets. Figure 9 shows the test arrangement. The

burner was left on for the first 200 s, and the tests were

run for 600 s. Each of the chairs was fabricated with a metal frame

and four upholstered cushions (0.61 X 0.61 X 0.1 m).

Thus, the chairs comprised only two combustible

components, the cushion padding and the previously

described upholstery fabric. They were tested with the

gas burner positioned along one side of the chair and

0.30 m above the test platform floor. Figure 10 shows

the test arrangement. The burner was left on for 200 s, and the fire was allowed to continue until all flames ex- tinguished on the chair. In cable tests No. 5 and 6, the cables were mounted

along a "Z"-shaped 0.46 m wide steel ladder. The upper and lower horizontal sections were 0.53 m long

each and the vertical section was 1.37 m long. Thirty

five cables were strung side by side across the width

on one side of the ladder with a half cable diameter

spacing away from each of the two edges of the ladder.

The cables filled the entire 2.44 m length of the ladder. The burner was placed 0.30 m directly under the

bottom of the vertical section. Figure 11 shows the test arrangement. The burner was left on for 200 s initially

and was reignited whenever self-extinguishment occurred. The duration of each re-ignition period was

chosen such that there was subsequent vigorous fire involvement of the cables before the burner was turned

off again.

Subsequent tests 19-21 of the cables were conducted

using a vertical ladder array of 25 cables, 2.18 m high

and placed side by side for a total width of 0.30 m.

Test 21 was only a test of the cable jackets. The inner

wires were removed and replaced with a solid copper

wire with a diameter of 0.08 m. The test arrays were

exposed for 1200 s to a 0.36 m wide line burner, which was chosen to provide greater flame coverage of the

cable array surface. The line burner was positioned 60

mm below the bottom of the cables with an offset of

about 13 mm towards the front of the cable array such

that the burner flames would initially contact the front

surface of the cables. Figure 12 shows the test arrangement. The fire was allowed to continue until all flames

extinguished on the cables.

In the circuit board tests, eight 0.91 m by 0.41 m by

6.4 mm thick specimen panels were placed in a vertical array with 25 mm spacing between panels. The gas

burner was located 0.30 m directly below the array. The cable array and the burner were housed in a

0.51 X 0.51 X 1.91 m high metal relay-rack type

cabinet, which had the top and lower 0.61 m of the

front open for ventilation. Figure 13 indicates the test arrangement. The burner was left on for the first 200

s and the test specimen panels were allowed to burn up

to 2500 s unless the fire extinguished sooner. For

materials which self-extinguished during the test, the

burner was re-ignited for various periods of time to further assess the materials under longer fire exposure

times.

3.2.3 GAS SAMPLING THROUGH IMPINGERS

Samples were collected from the exhaust gas stack on a platform above the Furniture Calorimeter hood.

A diagram of the gas sampling apparatus is shown in

Figure 14. A portion of the stack gases was drawn

through the impinger assembly with a sampling pump

controlled at nominally 1000 ml/min with an electronic mass flow controller. The flow rates through the
12 EXPERIMENTAL

impingers were verified with a laboratory dry-gas

meter. The ratio of gases collected to gases exhausted was approximately 1:100,000. Collection of sample

began when the specimen on the load platform was

ignited; collection was stopped when the flaming

stopped and no appreciable smoke was seen. The same PTFE filters and gas sampling impingers

previously mentioned were used. The solution in the

impingers was 5 mM KOH. The filters containing soot were placed into the solution from the first impinger.

The samples were then prepared and analyzed as described above.

3.2.4 FURNITURE CALORIMETER RESULTS

The Furniture Calorimeter results are summarized

in Table 7. The RHR curves for the tests are given in

Figures 15 to 19. In each case, the FR product was

notably better-behaved in its peak rate of heat release

characteristics. In some cases (the business machine

and TV housings, the circuit boards, and the cable ar- rays in the Z-arrangement) the FR product showed,

very roughly, half the RHR of the un-retarded one. In other cases (the chairs and the cable arrays in the vertical arrangement) the FR product showed no continued flame propagation at all, leading to RHR values

which are much less, but not strictly comparable to, those registered by the NFR product. Since it might

take just a little more external heating in order to show

complete and continued flame spread, the Furniture

Calorimeter test is not necessarily the final and

definitive test for those FR products which fail to show

continued flame spread when tested there. Instead, the

need is seen for ultimate validation with an appropriate room fire test. These will be discussed below.

3.2.5 DIRECT COMPARISON TO CONE

CALORIMETER RESULTS

Table 8 compares data obtained in the Cone

Calorimeter, and those gathered in the Furniture

Calorimeter. The simplest comparison is between the

bench-scale and the large-scale rates of heat release.

The quantities measured are, of course, not reported

in the same units, since in bench scale the value determined is the heat release per unit area (kW/m2 ), whereas in large scale, it is the heat release for the entire object (kW). Thus, only the relative magnitudes

must be compared, not the absolute numbers. For the

business machine housings, the television cabinets,

and the circuit boards, the comparison is consistent to within about 25 %

For the chairs and for the cables a good comparison

is not obtained. The analysis of the chair performance

is given in the following section. For the cables, the

bench-scale tests run on the composite specimens give

almost identical results for the FR product K and the

NFR product D. This is not surprising, since when

complete, composite specimens are tested, the behavior is dominated by the outer rubber jacket. This

jacket is the same for both specimens. In the Furniture

Calorimeter, however, the FR specimen K showed a

substantially better behavior than the NFR specimen

D. This may be explained the following way. The fire retardant agent in specimen K is only contained in the

wire insulation. In the large-scale test rig, the pyrolysis products of the burning section are swept up along

the not-yet-ignited upper portions of the specimen. In the case of specimen K, the FR agent is apparently active enough to stop flame spread from proceeding upwards. To examine the plausibility of this conjecture,

data from an additional Furniture Calorimeter test were obtained, where the wires had been removed

from the outer jacket, and only the jacket remained as a combustible. (The copper tube placed inside the

jacket served to preserve its dimensional stability.)

These data are shown in Table 7. The peak q for specimen K was 75 kW, while the peak q for the jacket-only

test was 140 kW. Thus, rate of heat release for the

jacket alone is greater than for the actual assembly of

jacket + wire, supporting the hypothesis that the

pyrolyzed FR agent from the wire insulation actually

stops the flame spread and burning of the jacketing

material.

For other variables of interest, in those cases where

the large-scale specimens did show continued flame

spread and combustion in the Furniture Calorimeter,

the fraction of the combustible mass lost was similar

to that observed in the bench-scale (Table 8). For

specimens, such as the FR circuit board or the FR

chair, where continued flame spread over the specimen surface was not sustained, the fraction of mass

lost in the Furniture Calorimeter was very small and was not comparable to the fraction lost in the Cone

Calorimeter. The circuit board L presents an interesting case; the total mass lost and the total heat

recovered were very small, yet a peak value of around

100 kW rate of heat release was observed, which is not

insignificant.

Comparing gas yields, in most cases the yield of CO

was higher in the Furniture Calorimeter than in the

Cone Calorimeter. The FR products typically showed

higher CO yields in the Furniture Calorimeter, compared to the NFR controls, but the relative NFR vs FR

differences in the Furniture Calorimeter were much

smaller in most cases than in the Cone Calorimeter. It

is interesting to note that the range of fractional CO

yields per unit mass of fuel burned in the Furniture

Calorimeter was quite small, with most products, both

NFR and FR, being clustered at around 0.10 to 0.13.
Furniture Calorimeter 13

The yields of C02 in the Furniture Calorimeter were closely comparable to those in the Cone Calorimeter, with the exception of specimens H, F, and L.

Since two of these are NFR products, and one is FR,

no significant difference between the predictability of

C02 yields of NFR vs FR products is seen. The acid gas (HC1, HBr, HCN) measurements show

very close agreement in all cases where data from

both instruments were available. Specimen T, while

disagreeing by 50% between the tests, in fact shows

small HCN yields, comparable to the measurement

limit. Data on recovery fractions of halogens were

available in both the Cone Calorimeter and in the Furniture Calorimeter only for Br for specimen G. In that case, both sets of results indicated a 71% recovery.

For smoke yields, the FR products behaved either

very similar to the NFR ones (business machine

housings, cables, upholstered chairs), or better (circuit board). The one anomalous case is of the TV cabinet housing where smoke yields were about double

for the FR specimen G, as compared to the NFR specimen H. Since bench-scale tests also showed this 2:1

difference, the finding seems validated.

The relationship of NFR to FR smoke yields was

very similar in both the Cone Calorimeter and the

Furniture Calorimeter in most all cases. Only in the case of the FR circuit board specimen L was this prediction poorly held. This is very simply attributed to the fact that the amount of specimen L which burned

in the Furniture Calorimeter was very small, therefore, yields of all products are highly uncertain. Comparing now the numerical values of the average smoke

extinction area obtained in the Cone Calorimeter and

in the Furniture Calorimeter, the values were typically

less in the Furniture Calorimeter by a factor of 2 to 3. This scale effect has been already noted in connection

with earlier studies on upholstered furniture [8]. In

the simplest case, one might suppose that the largescale and the bench-scale values ought to be identical.

Some recent data, in fact, suggest that identity between bench-scale and large-scale smoke values can be achieved if the m" (mass loss rate, per unit area)

values of the specimens are matched to be identical for

both cases [14] . Such matching can generally be done

by varying the external irradiance in the bench-scale

test. In that study [14], however, the articles were primarily burning in a fully-flame-involved manner for

nearly the entire duration of test. In the present study

(and also in the earlier upholstered furniture study),

the period of flame spread over the surface tended to comprise a large fraction of the total burning time.

Thus, it is possible that the reason why neither of

these studies shows such 1:1 matching might be due to flame spread effects. The one exception to the above was for the TV cabinet housings, where both the FR

specimen and the NFR one showed a greater smoke

yield in the Furniture Calorimeter than in the Cone

Calorimeter.

3.2.6 USE OF PREDICTIVE

SMALL-SCALE/LARGE-SCALE CORRELATIONS

As stated above, in general correlations have not yet

been developed for most classes of products which

would permit the engineer to accurately estimate the

likely large-scale fire performance, based on benchscale data alone. In some cases, however, such inroads

have started to be made. A recent review [15] summarizes the state of the art for such predictions for the

rate of heat release (q) and the mass loss rate (rh). Of

the products included in the present test series, a predictive correlation is available for upholstered chairs.

This correlation was derived for residential type of

furniture constructions, whereas the test program involves materials used for office occupancies. Nonetheless, it becomes interesting to examine the possible applicability of this correlation. According to this

prediction [15] , the peak rate of heat release is estimated to be

q — 0.63 q'bS [mass factor] [frame factor] [style factor]

(1)

The qHs is the bench-scale rate of heat release

(kW/m2 ), averaged over a 180 s interval, starting at the

time of ignition, on the composite foam/fabric speci- mens. For this correlation, the prescribed irradiance is 25 kW/m2

. Although 25 kW/m2 irradiance tests were

not conducted under the present program, only a very

small error is expected if the data from the 30 kW/m2

irradiance tests are used, instead. The mass factor is equal to the total combustible mass of the large-scale

article (kg). For the steel frames used in the present

tests, the frame factor is 1.66. The style factor is 1.0 for

the rectilinear construction used.

The measured 180 s average qHs values at 30 kW/m2

irradiance were:

310 kW/m2 for specimen T

165 kW/m2 for specimen S

Thus, for the NFR chair specimen T, the predicted

peak value of large-scale rate of heat release is 0.63(310)(5.5)(1.66)(1.0) = 1800 kW. For the FR chair

specimen S, meanwhile, the predicted value is 0.63 (165) ( 11 . 9) (1 .66) (1 .0) = 2100 kW. By contrast, the

measured values were 1200 kW for chair T and 50 kW

for chair S. Thus, the agreement is not very good.

The lack of agreement deserves some analysis. The

tests in the present test series were run at an irradiance
14 EXPERIMENTAL

of 30 kW/m2

, instead of the 25 kW/m2 used for the

original correlation. The numerical effect of this is ex- pected to be small, in the range of 5 to 10% , yet specimen T is over-predicted by some 50%.

For specimen S, the concern is of a very different

sort. The predictive correlation above is based on the

premise that flame spread covers all of the specimen,

and that essentially the whole combustible mass is consumed. In fact, sustained flame spread was not

observed over specimen S, and only a negligibly small

fraction of it was consumed. Some earlier work has

already identified that there is a limiting value of qZs , below which continued flame spread is not expected,

and, therefore, Equation 1 is not expected to be applicable [16]. This limiting value has not been wellcharacterized; a value of around 75 kW/m2 was suggested in [16]. Quintiere suggests a value of around

100 kW/m2 [17] . Specimen S, however, showed no sus- tained flame spread while having a ql's value of 165

kW/m2

. This suggests either that (a) a significantly

higher no-spread criterion value may have to be considered; or, (b) that the no-spread condition was due to very localized burning peculiarities adjacent to the igniting burner, and that a different burner arrangement

might, in fact, have led to sustained spread. Without

doing additional testing, the proper cause could not be

established.

3.3 SMALL-SCALE TOXICITY TESTS

The objective of this series of tests was to determine

whether the results of the small-scale tests would predict the toxicity (based on lethality) of the large-scale

tests. The smoke toxicity in both the small-scale tests and large-scale tests is predicted by the current N-Gas

Model which is based on data from earlier NBS ex- periments on the combined toxicity of the major gases

produced in fires [3,18]. The N-Gas model is designed

to determine whether the lethality of the thermal

decomposition products of a material can be explained

by the toxicological interaction of these major gases or

if other toxic combustion products need to be considered. The N-Gas model also permits the prediction

of approximate LC50 values based on the measured

concentrations of the predetermined set of gases and

knowledge of their toxicological interactions. The

LCS0 value is defined as the concentration which is

lethal to 50% of the test animals for a specific exposure time. Animal exposure experiments are con- ducted at the predicted LC50 value and if the prediction is correct, some percentage (not including zero or 100%) of the animals will die and the approximate

LC50 value is assumed to be close to the actual LC50 . Death of all the animals indicates that other toxic

gases are contributing to the toxic atmospheres. Currently, four gases, CO, C02 , HCN, and low 02 , have

been examined both individually and in various mixtures and are included in the model. (For some estimates below, however, approximate expressions for

HC1 and HBr effects are included, based on data re- ported by others.)

The bioassay based on the N-Gas model, thus, provides information on the toxic potency of the combustion products from a material which can be used to answer two questions:

(1) Does the material show normal toxic potency?

That is, does it show a value of the LCS0 which is comparable to products ordinarily found in a built

environment? For this study we shall consider any

substances showing LCS0 > 2 mg/1 as having

normal toxic potency. Conversely, any product

showing LCS0 < 2 mg/1 would be considered as having extreme toxic potency.

(2) Does the material show unusual toxicity? That is,

is any significant fraction of the toxicity not ac- counted for by the gases being monitored (CO,

C02 , HCN, low 02 , HC1, and HBr).

In this phase of the work, toxicity experiments involving both bioassay and analytical gas measurements were conducted to test the predictive capabilities of the

N-Gas Model. The materials were examined under

flaming conditions using the NBS toxicity test apparatus (Figure 20) [19]

3.3.1 ANIMALS

Fischer 344 male rats, weighing 200-300 grams, were obtained from Taconic Farms (Germantown,

NY). They were allowed to acclimate to our laboratory conditions for at least 10 days prior to experimentation. Animal care and maintenance were performed

in accordance with the procedures oudined in the National Institutes of Health's Guide for the Care and Use

of Laboratory Animals. Rats were housed individually

in suspended stainless steel cages and provided with

food and water ad libitum. Twelve hours of fluorescent

lighting per day were provided using an automatic

timer. All animals (including the controls) were

weighed daily from the day of arrival until the end of

the post-exposure observation period.

3.3.2 SMALL-SCALE TOXICITY TEST SYSTEM

The acute inhalation toxicity of the combustion

products of the above materials was assessed using the

N-Gas Model Toxicity Procedure (Table 9) which uses

the combustion system, the chemical analysis system

and the animal exposure system that was designed for

the NBS Toxicity Test Method [19]. This test method
Small-Scale Toxicity Tests 15

provides for both flaming and non-flaming exposures.

Since the large-scale test scenarios envisaged for the

present program did not involve any non-flaming conditions, only flaming exposures were conducted. Analytical experiments without animals were first con- ducted in order to determine the autoignition

temperature and the concentrations of CO, C02 , and

HCN that are generated from different mass loadings

of each material. These gas concentrations were then

used to predict an LCS0 value based on the N-Gas

model. Where possible, the animals were then ex- posed to a mass of material which was equal to this

predicted value. In certain cases, however, the animals

could only be exposed to the highest concentration

permitted by the physical limitations of the combustion system.

The animal exposure system is a closed design in

which all the gases and smoke are kept in the 200 1 rectangular chamber for the duration of the experiment. The materials are decomposed in a cup furnace

located directly below the animal exposure chamber

such that all the combustion products from the test materials are evolved directly into the chamber. For

this study, the materials were tested under flaming

conditions, achieved by setting the furnace 25 °C

above each material's predetermined autoignition temperature. When needed, ethanol or an electric spark was used to ensure immediate flaming.

In the animal exposure experiments, six rats were

exposed in each experiment. Animals were placed in

restrainers which were then inserted into the six portholes located along the front of the exposure chamber

such that only the heads of the animals were exposed.

The animals were exposed to the test atmospheres for

30 minutes. This exposure comprised an initial period

(which usually was about 5 minutes) during which the

test specimen was actively decomposing, as well as the later steady-state condition. The toxicological endpoint was death which occurred either during the 30

minute exposures or the post-exposure observation

period. This period was usually 14 days, but if animals were losing weight, they were kept until they either

died or recovered, as indicated by three days of weight

gain.

3.3.3 GAS ANALYSIS

Carbon monoxide and carbon dioxide were measured continuously by non-dispersive infrared analyzers. Oxygen concentrations were measured continuously with a paramagnetic analyzer. The CO,

C02 , and 02 data were recorded by an on-line computer every 15 seconds. All combustion products and

gases that were removed for these analytical measure- ments were returned to the chamber. The HCN generated from the nitrogen-containing polymers was

sampled approximately every three minutes with a

gas-tight syringe and analyzed with a gas chromatograph equipped with a thermionic detector [20].

These gas concentrations are provided as the timeweighted average values which were calculated for the

exposure period.

The presence of HBr in the gaseous combustion

products was determined by bubbling a portion of the

gases generated in the animal box through 3 ml impingers. The apparatus is diagrammed in Figure 21. The PTFE filter (0.45 /im nominal porosity) in this

test was 25 mm in diameter. The flow was generated

with a sampling pump and regulated with a rotameter.

The flow was nominally 30 ml/min and verified prior

to each test with a soap bubble meter attached to the

tube that protruded into the box. The duration of the

test was 30 minutes. In this test, the impingers contained approximately 2 ml of 5 mM KOH. After the

test, the PTFE filter containing the soot was placed in

the first impinger and the contents of each impinger were brought to 5 ml. The samples were then analyzed

for bromide ion as previously described.

3.3.4 N-GAS MODEL PREDICTION

The current N-Gas model is based on studies of the

toxicological interactions of four gases [3,18]. The fol- lowing equation has been experimentally derived to predict when 50% of the animals should die either

within the 30 minute exposures or within a 24 hour

post-exposure period. The current model does not

predict post-exposure deaths occurring after 24 hours.

For CO, HCN, C02 and low 02 :

m[CO] [HCN] 21 - [Q2] [C02] - b

+

LC50 HCN 21 - 5.4 (

'

where brackets indicate the actual concentration of the

gases; the LCS0 value of CO is based on 30 min exposures and is 6600 ppm; the LCS0 value of HCN is 160

ppm for deaths occurring within the 30 min exposure

or 110 ppm for deaths occurring during the exposure

or in the subsequent 24 hour post-exposure observation period; and 5.4 is the percent 02 that causes 50%

of the animals to die in 30 minutes. The terms m and

b equal — 18 and 122,000 if the C02 concentrations

are 5% or less and 23 and —39,000, respectively, if the C02 concentrations are above 5%. The period

under consideration here is restricted to 24 h, since

delayed deaths due to HCN are usually not found after

the first 24 h.

Since the concentration-response curves for animal

deaths from combustion products are very steep, the
16 EXPERIMENTAL

assumption is made that if any percentage of the animals die (not including 0 or 100%), the concentration

should be close to the LCS0 value. Examination of a

series of pure gas experiments in which various

percentages of the animals died indicated that the

mean N-Gas value was 1.07 with a standard deviation

of 0.10. This means that the 95 % probability that some

animals will die as a result of exposure to these primary gases falls within the range of 0.87 to 1.27. Deaths below this range may then be attributed to the

additional toxicity contributed by other gases or factors. Above this range, all the animals would be ex- pected to die.

3.3.5 RESULTS AND DISCUSSION OF THE

SMALL-SCALE TOXICITY TESTS

All the bench-scale chemical and toxicological data

obtained for the test specimens in the N-Gas Model

Toxicity Procedure are presented in Table 10. With no

animals present, each material was first tested in the

flaming mode (25 °C above its predetermined autoignition temperature) at a mass loading of 40 mg/1 to obtain the necessary analytical gas data to calculate the

value of the 4-Gas Model prediction. In Table 10, the

analytical data for each material are given first, before

the experiments in which animals were exposed. For

ease in interpretation of the present test results, toxicity results for a number of common materials previously studied [19] are summarized in Figure 22.

When 40 mg/1 (mass loading or mass consumedchamber volume) of the NFR television cabinet (Specimen H) was decomposed in the flaming mode, the 4-

Gas Model prediction value ranged from 0.93 to 0.99

and one of the six exposed animals died during the ex- posure. When the mass loading and mass consumed

was reduced to 30 mg/1, no deaths were noted. Therefore, the estimated LC50 value is approximately 40

mg/1 and the toxicity of the combustion products of

this material would not be considered extremely toxic.

Since the 4-Gas Model prediction value is approximately 1.0 at the LCso, the toxicity of the measured

gases alone is considered responsible for the observed

deaths.

Similar to its NFR counterpart, the FR television

cabinet (Specimen G) decomposed in the flaming

mode was completely consumed during the 30 minute

exposure. Therefore, the mass loading/chamber

volume is equivalent to the mass consumed/chamber

volume. However, this FR specimen did not maintain

the flaming condition unless the ignition spark was left on continuously. Consequently, with the exception of

the first experiment, all the tests on this material were

conducted with the ignition spark on throughout the

exposure. At 40 mg/1, the 4-Gas Model prediction

value was higher (1.42-1.54) in the cases where the

sparker was left on compared to the test (0.65) in

which the sparker was turned off after the material ignited. At this 4-Gas Model prediction value, all the

animals died as expected. At 20 mg/1, the 4-Gas

Model prediction value was 0.56 and no animals died

either during or following the exposures. At 30 mg/1,

the 4-Gas Model prediction value was 0.79 and while no animals died during the exposure, two died within

the first 24 hours of the post-exposure period. These

results indicate that the estimated LC50 value is close

to 30 mg/1; therefore, the toxicity of the combustion

products of this material is not extremely potent.

However, since the 4-Gas Model prediction value at the estimated LCS0 is 0.79, which is below the lower

95 % confidence limits of the range where deaths are expected, another gas or gases may be contributing to the post-exposure deaths. The average 30-minute concentration of HBr in this experiment was 163 ppm. At

the present time, HBr is not one of the gases included

in the 4-Gas Model; however, if one considers the tox- icological contribution of this gas as an additional additive factor and assumes the 30-minute LC50 value as 3000 ppm [5], another 0.05 would be added to the 4-

Gas Model prediction value (i.e., 0.84). This value of

the 4-Gas Model is now fairly close to the lower 95 %

confidence limits and it is uncertain as to whether a

further gas is contributing to the toxicity of these combustion atmospheres.

At a 40 mg/1 loading, the value of the 4-Gas Model

prediction for the NFR business machine (Specimen

F) was determined as 1.47. Consequently, the loading

of material into the furnace was decreased such that

the value of the 4-Gas Model prediction was 1.08, a value at which deaths of some of the animals would be

expected. In actuality, no animals died either during

or post-exposure from this experiment. Therefore, the mass loading was increased such that the 4-Gas Model

prediction value was 1.36; at this loading, all of the

animals died within the exposure as expected. These

data indicate that the LCS0 value is between 32 and 35

mg/1 mass loaded (30 to 33 mg/1 mass consumed) or in

terms of the 4-Gas model prediction values, between

1.08 and 1.36. Therefore, the toxicity can be attributed

to the series of gases that were monitored. Thus, this

material is neither extremely toxic nor unusually toxic

(i.e., gases other than the major ones measured are not contributing to the toxicity)

The chemical and animal exposure results from the

FR business machine housing (Specimen A) indicated

that the estimated LCS0 value was about 25 mg/1 based on mass loaded (24 mg/1 based on mass consumed)

and that the FR specimen is slightly-but not toxicologically significantly— more toxic than the NFR specimen. Since 4 out of 6 animals died at an exposure in
Small-Scale Toxicity Tests 17

which the 4-Gas Model prediction value was 1.13, this

material is also not unusually toxic.

The NFR flexible polyurethane foam corresponding

to Specimen T, when decomposed in the flaming

mode at a mass loading/chamber volume of 40 mg/1

(35 mg/1 mass consumed/chamber volume), produced

4-Gas Model prediction values of 0.55 or 0.60 for

within- and post-exposure deaths, respectively (the

difference between these two numbers depends upon

the value of the LCS0 used for HCN). No deaths oc- curred from this exposure indicating that the LCS0 value of this material is >35 or >40 mg/1 depending

on whether the mass consumed or mass loadedchamber value is used for the calculation. Therefore,

the toxicity of the combustion products would not be

considered extremely potent. Since experiments could

not be conducted at loadings closer to the LC50 value,

it was not determined if the toxicity of lethal levels of

the combustion products can be explained by the combined measured gases or if other gases are needed.

However, the contribution of additional gases would

only be <30%.

The FR flexible polyurethane foam, corresponding

to Specimen S, did not burn in a consistent manner;

hence, there were a number (4) of analytical runs

(without animals) at a mass loaded/chamber volume

of 40 mg/1 (24-26 mg/1 mass consumed/chamber

volume). Since all but one of these tests were at 550°C, only the 550°C tests will be discussed. Even

at the same mass loading (40 mg/1), the 4-Gas Model

prediction value varied between 0.74 and 1.10

(calculated for within-exposure deaths) or 0.80 and

1.23 (calculated for post-exposure deaths). Two animal experiments were performed at mass loadings/

chamber volume of 30 and 35 mg/1 (20 and 23 mg/1

mass consumed/chamber volume, respectively). No

animals died during either of the exposures; however,

two animals died during the first 24 hours following

exposure to the combustion products from the experiment with the higher mass loading. The estimated

LC50 value is approximately 35 mg/1 or 23 mg/1 based on mass loaded or consumed/chamber volume, re- spectively. The toxicity of the combustion products

would not be considered extremely potent. Since only

two animals died post-exposure at a 4-Gas Model Prediction value of 1.23, the toxicity of these combustion

products can be attributed solely to those gases that were monitored.

The NFR wire insulation, corresponding to Specimen D, decomposed in the flaming mode at a mass

loading/chamber volume of 40 mg/1 (34 mg/1 mass

consumed/chamber volume) produced a 4-Gas Model

Prediction value of 0.66. Unless other gases were contributing to the toxicity, this value would not be ex- pected to cause any deaths and, in fact, no deaths were

noted in the corresponding experiment. When the

amount of material loaded (and consumed) was doubled, the 4-Gas Model prediction value was 1.47 and

as expected, all of the animals died during the exposure. The estimated LCS0 is between 40 and 80 mg/1

based on mass loaded/chamber volume or between 34

and 68 mg/1 based on mass consumed/chamber vol- ume. These LC50 values indicate that the toxicity of this

material is not extremely potent. Due to the screening

nature of this experimental series, it is unclear

whether additional gaseous agents need to be sought.

When 40 mg/1 (mass loaded/chamber volume or 32

mg/1 mass consumed/chamber volume) of the FR wire

insulation (from Specimen K) was decomposed in the

flaming mode, the 4-Gas Model prediction value was

0.71 when no animals were present and 0.81 when animals were exposed (the animals can contribute to the

C02 concentrations and reduce the 02). At this loading, one animal died during the exposure and all the

animals died within 24 hours following the exposure.

Although half of this loading produced a 4-Gas Model

prediction value of only 0.41, one animal died during

the post-exposure observation period on day 19

(Figure 23). Since the LC50 of this material is between

20 and 40 mg/1 based on mass loaded/chamber

volume or between 17 and 33 mg/1 based on mass con- sumed/chamber volume, the toxicity of the combustion products would not be considered extremely

toxic. However, since the 4-Gas Model prediction

value at the LCS0 is between 0.41 and 0.81, one or more

gases, other than those monitored, are contributing to the toxic combustion atmospheres. Procedures for including HC1 toxicity in the NBS Toxicity Test Method

have not yet been worked out. Since the main additional toxic agent expected would be HC1, it is possible to estimate its expected effect. The yield of HC1 in

the Cone Calorimeter for this specimen was 0.095

kg/kg (Table 2). If this same HC1 yield is also realized

in the NBS Toxicity Test Method, then HC1 concentration within the box would be 2500 ppm. Using 3700

ppm as the 30-minute ( + 14 day post-exposure) LC50 value for HC1 [5], the contribution of HC1 would be

2500/3700 = 0.68. If linear additivity holds for HC1

in conjunction with the other gases, this would change

the prediction value from being 0.41 to 0.81 to being

1.09 to 1.49. This range is within the area where animal deaths (primarily occurring post-exposure, due to HC1) are successfully accounted for. Additional

research, however, would be needed to confirm this

prediction.

The NFR circuit board (Specimen C), when decomposed at a mass loading/chamber volume of 41 mg/1

(12 mg/1 mass consumed), produced very low amounts

of the monitored gases. The 4-Gas Model prediction

values for the experiments without and with animals
18 EXPERIMENTAL

were only 0.18 and 0.21, respectively. This indicated

that only about 20% of the toxic gases had been produced by this loading of material. An increase in the

loading such that the 4-Gas Model prediction value was approximately unity (1.08) resulted in no deaths

during or following the exposure. However, an in- crease in the loading that produced a 4-Gas Model

prediction value of 1.38 caused all the animals to die

within the exposure period. From these data, a LCS0 value based on mass loaded/chamber volume can be

estimated as between 165 and 200 mg/1; if the LC50 value is based on mass consumed/chamber volume,

then the value is between 48 and 58 mg/1. Either way

the toxicity of this material would not be considered

extremely potent. Since the 4-Gas Model prediction

value at the LCS0 value is between 1.08 and 1.38, this

material is not unusually toxic.

The FR circuit board (Specimen L) when decomposed in the flaming mode at a mass loading/chamber

volume of 40 mg/1 (19 mg/1, mass consumed/chamber

volume) produced concentrations of CO, C02 , and 02 which resulted in a 4-Gas Model prediction value of

approximately 0.40. This 4-Gas value would not be ex- pected to produce deaths and no deaths occurred.

When this mass loading/chamber volume was doubled

(85 mg/1 loaded, 36 mg/1 consumed), the 4-Gas

Model prediction value increased to 0.76, which is still below the amount necessary to cause deaths if those

deaths are due to the gases being monitored. Again, no deaths occurred. At a mass loading of 100 mg/1 (45

mg/1 consumed), the 4-Gas Model prediction value was 1.13 and all the animals died. This indicates that

the estimated LCS0 value lies between 85 and 100 mg/1

based on mass loading or between 36 and 45 mg/1

based on mass consumed. In either case, the toxicity

of the flaming combustion products of this material

would not be considered extremely potent. Since all the animals died at a 4-Gas Model prediction value of

1.13 and none died at 0.76, it is unclear what the 4-gas

prediction value would be at the LCS0 , and, thus, it is not known whether other gases are contributing to the

toxicity in this case. The results of the small-scale toxicity tests are summarized in Table 11.

table 1 Cone Calorimeter Data Summary—30 kW/m2 Irradiance Tests.*

Ign. Peak Peak Tot. Eff. NFR Mass % Mass Time q" time q" Ahc Sample /FR (9) burned (s) (kW/m2

) (s) (MJ/m2) (MJ/kg)

TV Cabinet H NFR 34 99 107 970 190 87 30

TV Cabinet G FR 38 98 84 340 184 46 12

Bus. Machine F NFR 37 88 108 650 168 96 30

Bus. Machine A FR 39 81 134 380 370 65 21

Chair T

a NFR 23 89 14 470 113 54 27

Chair S

a FR 43 67 34 290 51 51 18

Chair T

b NFR 15 90 2 540 65 34 27

Chair S

b FR 36 61 25 180 32 15

Cable D NFR 166 35 383 360 505 156 28

Cable K FR 170 33 374 380 487 114 23

Cable D

c NFR 54 52 189 270 208 65 23

Cable K

c FR 53 54 169 280 185 68 23

Cable D

d NFR 103 22 137 740 280 91 39

Cable K

d FR 106 22 131 260 161 51 23

Circuit Bd. C NFR 123 28 199 250 220 73 21

Circuit Bd. L FR 117 36 315 100 368 55 13

'Estimates of uncertainty (median values), expressed as coefficients of variation, are: sample mass = 1 .9%

°/o mass burned = 1 .3%

ignition time = 8.7%

peak q " = 8.6%

peak time = 6.3%

total q" = 2.9%

eff. Ahc = 3.1%

a Foam and fabric cover combination

bFoam only, no cover

cCable jacket only

dWire alone; jacket stripped off
table 2 Cone Calorimeter Data Summary—Test Average Data at 30 kW/m2 Irradiance.*

NFR CO C02 HCI HBr HCN Smoke

Sample /FR kg/kg kg/kg kg/kg kg/kg kg/kg m

2/kg

TV Pahinot H NFR iNrn 9 9R4 mio i \i i \j TV Cabinet G FR 0.109 0.671 0.069 1880

DUo. IVIdUl 111 it; r NFR n n?7 9 911 1710

Bus. Machine A FR 0.055 1.604 1660

NFR 0.020 1.617 0.002 410

Chair S

a FR 0.051 0.964 0.022 0.005 480

Chair T

b NFR 0.016 1.711 0.002 270

Chair S

b FR 0.055 0.809 0.022 0.002 280

Cable D NFR 0.041 1.773 0.112 1010

Cable K FR 0.060 1.337 0.131 _ 880

Cable D

c NFR 0.029 2.190 690

Cable K

c FR 0.135 1.004 0.095 — — 1030

Cable D

d NFR 0.030 2.208 n 1 9fl 7in

Cable K

d FR 0.142 0.991 0.136 — 1000

Circuit Bd. C NFR 0.014 2.070 560

Circuit Bd. L FR 0.103 0.868 0.022 400

'Estimates of uncertainty (median values), expressed as coefficients of variation, are: CO = 7.3%

C02 = 7.9%

smoke = 8.4%

Due to limited amount of data, estimates are not derived for HCI, HBr, and HCN.

^oam and fabric cover combination foam only, no cover

°wire alone; jacket stripped off "cable jacket only

table 3 Cone Calorimeter Data Summary—-100 kW/m2 Irradiance Tests.*

Ign. Peak Peak Tot. Eff. NFR Mass % Mass Time q" time q" Ahc Sample /FR (g) burned (s) (kW/m2

) (s) (MJ/m2) (MJ/kg)

TV Cabinet H NFR 32 97 15 1400 68 9Q

TV Cabinet G FR 36 95 13 480 55 39 10

Bus. Machine F NFR 37 88 11 1100 46 9Q

Bus. Machine A FR 35 87 11 570 41 60 20

Chair T

a NFR 22 93 5 1460 52 JO 9R

Chair S

a FR 45 72 5 760 22 56 18

Chair T

bd NFR 14 88 <1 1580 35 o / 9Q

Chair S

bd FR 37 66 2 310 15 35 14

Cable D NFR 170 38 8 550 225 159 26

Cable K FR 173 35 10 380 32 119 21 Cable D

c NFR 102 23 16 1280 93 88 38

Cable K

cd FR 106 23 16 490 45 50 21

Circuit Bd. C NFR 127 29 32 250 160 71 18

Circuit Bd. L FR 116 43 49 147 128 74 14

•Estimates of uncertainty (median values), expressed as coefficients of variation, are: specimen mass = 2.7%

mass burned = 4.1%

ignition time = 10.7%

peak q" = 6.1%

peak time = 1 0.4%

total q" = 5.4%

eff. Ahc = 3.9%

a Foam and fabric cover combination

bFoam only, no cover fabric °Wire alone; jacket stripped off dOnly one test value

19
table 4 Cone Calorimeter Data Summary—Test

Average Data at 100 kW/m2 Irradiance.*

NFR CO C02 Smoke

Sample /FR (kg/kg) (kg/kg) (m2/kg)

TV Cabinet H NFR 0.063 2.121 1430

TV Cabinet G FR 0.074 0.564 2010

Bus. Machine F NFR 0.060 1.627 1530

Bus. Machine A FR 0.096 1.165 2120

Chair T

a NFR 0.021 1.828 340

Chair S

a FR 0.063 0.965 500

Chair Tbd NFR 0.018 1.889 450

Chair S

bd FR 0.052 0.895 420

Cable D NFR 0.007 1.566 1270

Cable K FR 0.025 1.245 1210

Cable D

cd NFR 0.035 2.148 760

Cable K

cd FR 0.101 0.910 1290

Circuit Bd. C NFR 0.012 1.697 780

Circuit Bd. L FR 0.012 1.221 410

"Estimates of uncertainty (median values), expressed as coefficients of vari- ation, are: CO = 14.3%

C022 = 4.4%

smoke = 5.6%

aFoam and fabric cover combination

bFoam only, no cover fabric °Wire alone; jacket stripped off dOnly one test value

table 5 Irradiance Threshold Limit for Foam S with Nylon Fabric Cover.

Ign. Peak Total Eff. Test Irrad. Mass Mass % time Peakq" time q" Ahc CO C02 Smoke Soot

Number (kW/m2

) (g) burned (s) (kW/m2) (s) (MJ/m2) (MJ/Kg) (kg/kg) (kg/kg) (m2/kg) (kg/kg)

2590 7 43 Nl 2592 10 43 14.3 541 180 580 9.6 15.7 0.035 1.558 350 0.056

2593 10 43 Nl 2594 11 44 20.5 341 190 370 13.1 14.6 0.035 0.677 380 0.052

2595 11 43 Nl 2596 11 42 16.9 527 50 815 5.6 7.8 0.053 0.558 590 0.103

2597 11 43 19.8 264 180 295 13.4 15.7 0.031 0.573 380 0.052

2591 15 43 41.2 173 280 210 22.0 12.5 0.036 0.888 420 0.039

20
table 6 Summary of Furniture Calorimeter Test Conditions.

Specimen Time Period Time

Specimen

NFR

/FR Test

Mass for Burner on

(kg) (s)

Duration

(s)

TV Cabinet H NrH oO 3.7 0-200 600

TV Cabinet G FR 4 3.7 0-200 600

TV Cabinet G FR 15 3.7 0-200 r\ 660

Bus. Machine F NFR 1 3.5 0-200 600

Bus. Machine A FR 2 3.5 0-200 600

Chair T NFR 16 5.5 0-200 600

Chair T NFR 18 5.3 0-200 600

Chair S FR 17 11.9 0-200 345

Cable D

a NFR 5 17.5 If 0-200 1400

\

I 240-600

0-200

Cable K

a rnFR 6 18.2

|

240-600 2000

[730-1380

Cable D

b NFR 19 11.4 0-1200 1200

Cable K

b FR 20 11.5 0-1200 1860

Cable K

c FR 21 12.0 0-1200 840

Circuit Bd. C NFR 10B 36.6 0-200 2400

f 0-200

Circuit Bd. L FR 11 34.8

|

255-495 1900

(626-1800

aZ-configuration

bVertical configuration

cJacketing only, with an 8 mm O.D. copper tubing insert replacing the contents

table 7 Summary of Furniture Calorimeter Results.

Bus. Cable (vertical Cable (Z

TV Machine Chair configuration) configuration) Circuit Board

Product NFR FR FR NFR FR NFR NFR FR NFR FR NFR FR NFR FR

Specimen Code H G G F A T T S D K Jacket D K C L

Test No. 3 4 15 1 2 16 18 17 19 20 21 5 6 10B 11

Total Mass kg 3.7 3.7 3.7 3.5 3.5 5.5 5.3 11.9 11.35 11.52 3.5 I7.5 18.2 Combustible Mass kg 3.7 3.7 3.7 3.5 3.5 5.5 5.3 11.9 6.24 6.45 3.5 9.6 10.2 36.6 34.8

Mass Loss kg 3.6 2.1 2.0 3.2 2.5 5.2 5.1

* * 4.6 1.60 2.0 3.5 2.2 13.4 1.9 Peak Heat Release Rate kW 515 180 175 560 380 1160 1205 50* 400 75* 140 245 130 205 100*

(Time of Occurrence) s 139 216 88 138 186 218 208 209 858 1208 265 839 1402 396 1863

Total Heat MJ 83 40 40 75 69 136 135 * 188 * 67 124 75 238 *

Average Heat of Combustion MJ/kg 23 20 20 24 28 26 27 * * * 41 34 35 34 18 *

Average CO kg/kg 0.12 0.48 0.26 0.13 0.29 0.01 0.01 0.12 0.10 0.13 0.25 0.30 0.10 0.10

Average C02 kg/kg 1.39 0.72 0.75 1.61 1.45 1.88 1.89 * * 1.61 1.04 1.48 1.89 0.70 1.71 1.36 Average HCI kg/kg 0.1

2

a 0.1

3

a Average HBr kg/kg 0.083 Average HCN kg/kg 0.001 a

Average Smoke Extinction Area m

2/kg 1320 2690 2910 1145 1280 210 165 180 280 235 560 375 545 285 115

'Not reliable. Specimen heat release rate accuracy of ± 25 kW

"Not reliable. Specimen weight loss comparable to noise level of instrumentation determined by ion chromatography

21
table 8 Comparison of Cone Calorimeter Versus Furniture Calorimeter Data.

NFR

Pk RHR (kW/m2

) 8 Ahc (MJ/kg) 0/n/O hi irnorl Avg. CO (kg/kg) Avg.C02(kg/kg)

Sample /FR Cone Furn." Cone Furn.b Cone Furn. b Cone Fum.b Cone Furn."

TV Pahinot W NFR in rn 970 520 30 23 QQ Q757/ 0.015 0.12 2.28 1.39 TV Cabinet G FR O A f\ 340 H OO loO 1 C. or* 20 98 57 0.109 0.37 0.67 0.74

Rue DUO. h/lar-hino Ivldl^l III IC P1 NFR INrn 650 560 30 24 53 1 0.037 0.13 2.21 1.61 Bus. Machine A FR OOU co 81 71 U.UOO 1 .DU A A (5

\ .40

Chair T NFR 11 1RD 1 ou Cm97I 97 89 96 \J.\JC-\J U.U I I .053 Chair S FR 290 50 18 c.d 67 d 0.051 d 0.96 d

Cable D NFR 360 400 28 41 35 41 0.041 0.12 1.77 1.61 Cable K

rh

rn 380 80 23 c 33 14 0.060 0.10 1.34 1.04

Circuit Bd. C NFR 250 210 21 18 28 37 0.014 0.10 2.07 1.71

Circuit Bd. L FR 100 100 13 C 36 5 0.103 0.10 0.87 1.36

NFR

HCI (kg/kg) HBr (kg/kg) HCN (kg/kg) Smoke (m2/kg)

Sample /FR Cone Furn. b Cone Fum.b Cone Furn. b Cone Furn. b

TV1 V flahinpt UdUII Id H11 NFR NM NM NM NM NM NM 1010 1320

TV Cabinet G FR NM NM 0.07 0.08 NM NM 1880 2800

NFR NM NM NM NM NM NM 1710 1150

Bus. Machine A FR NM NM NM NM NM NM 1660 1280

Chair T NFR NM NM NM NM 0.002 0.001 410 190

Chair <? vyl ICtll O FR111 0.02 NM TR NM 0.005 d 480 180

Cable D NFR 0.11 0.12 NM NM NM NM 1010 280

Cable K FR 0.13 0.13 NM NM NM NM 880 240

Circuit Bd. C NFR NM NM NM NM NM NM 560 290

Circuit Bd. L FR NM NM 0.02 d NM NM 400 120

NOTE: All Cone Calorimeter data refer to 30 kW/m2 irradiance tests. aValues for the Cone Calorimeter refer to peak qb's (kW/m2

); values for the Furniture Calorimeter refer to peak q (kW). 'Values obtained from the following Furniture Calorimeter tests: H: 3

G: 4,15

F: 1 A: 2

T: 16,18

S: 17

D: 19

K: 20

C: 10B

L: 11

c Not reliable. Specimen heat release rate accuracy of ± 25 kW

dNot reliable. Specimen weight loss comparable to noise level of instrumentation NM Not measured

TR Trace

table 9 N-gas Model Toxicity Procedure.

1 . Material is thermally decomposed.

2. Concentrations of major toxicants are measured.

3. LC50 is predicted based on experimental data of toxic interactions.

4. Rats are exposed to predicted LC5o5. If some percentage die, can attribute cause to major toxicants.

6. Death of all animals indicates other gases are contributing to

toxicity. A. Determine the LC50 value.

B. Low value means extremely toxic. C. Need to include other toxic gases means unusually toxic.

Advantages

1 . Rapid screening test

2. Economical

3. Minimizes the use of animals

4. More information than just toxic potency

22
table 10 Chemical and Toxicological Results from Materials Decomposed in the Flaming Mode.

Mass Gas Concentrations8 Deaths

Expt. N-Gas

NFR Temp. Load Cons. CO C02 HCN 02 HBr Prediction Within Within Latest Day

Specimen /FR Material (°C) (mg/l) (ppm) (ppm) (ppm) (%) (ppm) Within Post Exp. & Post of Death

TV Cabinet H NFR polystyrene 550b 40 40 2740 40600 NDT° 15.3 NDd 0.99 ou ^n OcJ^IUU oQonn I o.o U.Oo u/o u/o

40 40 2560 39800 ND 15.4 ND 0.93 1/6 1/6 0

TV Cabinet G FR polystyrene \JC\J 40 1Q 7 MDI N U n pis 40f 40 7400 20800 ND 17.9 ND 1.54 Z

'

,

20' 20 2740 12300 ND 19.4 ND 0.56 — 0/6 0/6 —

30' 30 3840 14000 ND 18.9 163 0.79 0/6 2/6 1

*fU ACi DO / U MnINU 17 O MnINU 1 AO O/O O/O u

Bus. Machine F NFR polyphenylene 600 40 38 5100 38600 ND 15.7 ND 1.47 oxide 32 30 3800 33600 ND 16.5 ND 1.08 0/6 0/6

35 33 4700 37800 ND 15.8 ND 1.36 6/6 6/6 0

Bus. Machine A FR polyphenylene •5 75 40 JO NDINI-' 1fi 1 u. 7/ NDI N U 11.71 Q1

oxide 25 24 5000 23400 ND 17.9 ND 1.13 z 4/6 4/6 0

Ohair roam I NFR polyurethane 4259 40 35 680 36800 16 16.2 ND 0.55 0.60 —

/in *fU OO oyu oy^uu 1 A 1 fi 1 U.OO nU.DUfin u/o u/o

Chair foam S FR polyurethane 525 40 26 2800 13900 38h 19.2 ND 0.83 0.94 — — —

550 40 26 2800 14100 24h 19.2 ND 0.74 0.82 — — ' -

OA O91I nnuu i oouu I / Mn u. / o U.OU 40 26 3600 20200 45h 18.4 ND 1.10 1.23 z

30 20 2700 18400 68h 18.7 ND 1.05 1.25 0/6 0/6

35 23 3000 19400 60h 18.7 ND 1.06 1.23 0/6 2/6 1

Cable D NFR EVA 1A I 04U OODUU MnINU I O.o Mn U.OO 40 34 1270 41600 ND 14.8 ND 0.69 0/6 0/6

80 68 4420 66600 ND 12.9 ND 1.47 6/6 6/6 0

Cable K FR EVA 450 40 32 3080 17200 ND 18.4 ND 0.71 — — —

20 17 1650 13500 ND 18.9 ND 0.41 0/6 1/6 19

40 33 3150 23500 ND 17.6 ND 0.81 1/6 6/6 1

Circuit Bd. C NFR polyester 550 41 12 600 12700 ND 19.7 ND 0.18

41 12 600 15600 ND 19.3 ND 0.21 0/6 0/6

165 48 3010 45700 ND 15.5 ND 1.08 0/6 0/6

200 58 3870 50600 ND 15.0 ND 1.38 6/6 6/6 0

Circuit Bd. L FR polyester 625 40 19 2030 10800 ND 19.7 ND 0.42

41 19 1850 9800 ND 19.7 ND 0.39 0/6 0/6

60 28 3000 18200 ND 18.4 45 0.70 0/6 0/6

85 36 3240 20200 ND 18.3 39 0.76 0/6 0/6

100 45 4820 25000 ND 17.6 57 1.13 6/6 6/6 0

"Average concentration over 30-minute exposure.

b

ln non-flaming mode, no deaths occurred.

qNDT = Not detected.

dN = Not determined.

eSparker turned off after first flicker. 'Sparker on until flaming stopped.

9

ln non-flaming mode at 40 mg/l, 3/6 animals died on days 7, 1 1 , and 14.

h HCN results were variable. N-Gas prediction based on equation:

m[CO] [HCN] 21 -[Q2] [C02]-b +

X +

21-5.4

where m = slope of LC50 line of CO in the presence of C02 and b = the y intercept of this line. Values used for m (-18.4 or 22.7 when C02

is below or above 5%, respectively) and b (122,000 or -39,000 when C02

is below or above 5%, respectively) were based on data obtained after 1/1986. X = LC50

value of HCN which is 160 ppm for deaths during the 30-min exposures and 110 ppm when deaths occur within 24 hours post-exposure. 5.4% is the 1986

30-min LC50 value for O

2

.

23
table 11 Summary of LC50 Values and 4-Gas Model Prediction Values Determined in the Small-Scale Toxicity Tests.

Estimated LC5o Estimated LC50

Mass Loading Mass Consumed N-Gas

(mg/l) (mg/l) Prediction Model

; Other Extreme

Specimen

NFR

/FR Material

Within

Exp.

Within &

Post-Exp.

Within

Exp.

Within &

Post-Exp.

Within

Exp.

Within &

Post-Exp.

Gases

Needed

Toxic

Potency

TV Cabinet H NFR polystyrene 40 40 40 40 1.0 1.0 No No

TV Cabinet G FR polystyrene 30-40 30 30-40 30 0.79-1.42 0.80 ? No

Bus. Machine F NFR polyphenylene 32-35 32-35 30-33 30-33 1 .08-1 .36 1.08-1.36 No No

oxide

Bus. Machine A FR polyphenylene 25 25 24 24 1.13 1.13 No No

oxide

Chair T (foam) NFR polyurethane >40 >40 >35 >35 >0.56 >0.60 ? No

Chair S (foam) FR polyurethane >35 = 35 >23 «23 >1.06 = 1.23 No No

Cable D NFR EVA 40-80 40-80 34-68 34-68 0.69-1.47 0.69-1.47 ? No

Cable K FR EVA >40 20-40 >33 17-33 >0.81 0.41-0.81 Yes No

Circuit Bd. C NFR polyester 165-200 165-200 48-58 48-58 1.08-1.38 1.08-1.38 No No

Circuit Bd. L FR polyester 85-100 85-100 36-45 36-45 0.76-1.13 0.76-1.13 ? No

24
r- Laser extinction beam including

temperature measuring

Vertical orientation

Figure 6. Conceptual view of the Cone Calorimeter.

25
Main exhaust duct

of Cone Calorimeter

250 mL impingers

0404 5 mm

Teflon filter

Existing mass

flow controller (used for soot sampling)

Figure 8. Impinger gas sampling in the Cone Calorimeter.

Two 0.36x0.36x0.25 m high cabinets with 25 mm spacing between cabinets

50 kW diffusion flame burner PLAN VIEW

front

Stack

1.7 m3/s

flame burner Marinite drip collector board 13 mm below burner

Figure 9. Furniture Calorimeter test of business machines and TV

cabinets.

Stack

50 kW diffusion flame burner, top surface 0.30 m above Marinite table

Figure 10. Furniture Calorimeter test of chairs.

26
Stack

Figure 12. Furniture Calorimeter test of cables (vertical array).

27
Stack

50 kW diffusion flame burner

Figure 13. Furniture Calorimeter test of circuit boards.

Furniture calorimeter 25 mL impingers Three way

Glass wool Teflon filter trap controller

soot trap

Figure 14. Impinger gas sampling in the Furniture Calorimeter.

28
1000

180 360 540 720 900 1080 1260 1440 1620 1800

TIME (s)

Figure 15. Rate of heat release for TV cabinets measured in the Furniture Calorimeter.

1000

ID<

tr

ID

in<

ID

_lID

<

IDI

180 360 540 720 900 1080

TIME (s)

1260 1440 1620 180(

Figure 16. Rate of heat release for business machine housings

measured in the Furniture Calorimeter.

29
0 180 360 540 720 900 1080 1260 1440 1620 1800

TIME (s)

Figure 17. Rate of heat release for upholstered chairs measured in the Furniture Calorimeter.

30
2 t/min.

COMBUSTI

ANIMAL

EXPOSURE

BOX

ONJ

HCN SAMPLING PORT

GASES

LIINU rUH r 7

ULTU^LJUir

ANIMAL EXPOSURE

PORTS

R - Rotameter

ANALYZED COMBUSTION GASES

Figure 20. Schematic of gas analysis system used in the small-scale

toxicity test.

31
200 L

animal box

3 mL impingers

/

Rotameter

25 mm

Teflon filter

25 mL

empty trap

Pump

r

To

atmosphere

Vent valve

Figure 21. Impinger gas sampling in the small-scale toxicity test.

-i—i—i i i 1

1

i i i i i i 1 1

~i i i i i i i T 1 1 I Mill

LC50

(30 min.)

LC50

(30 min. 1 14 days)

EC50

(30 mm.)

• ABS * DFIR- O DFIR - A FPU

MOD

PPS - PSTY

PTFE

O PVC

PVCZ

REDO

RPU

WOOL

I

i i i i I J I '

I

' '

I J I

i i i i i il J I '

10 10 10 10 MASS LOADING/CHAMBER VOLUME (mg/l)

Figure 22. Comparison of materials by their EC50 , LC50 (30 min.) and

LC50 (30 min. + 14 days) after flaming decomposition.

10

32
135 -

160 ' 1 1 1 1 1 1 1 1 1 1 -10 -5 0 5 10 15 20 25 30 35 40

TIME (daya)

Figure 23. Animal weight change following a 30 minute exposure to

the flaming decomposition products from a mass loading of 20 mg/1 of specimen K.

33

4

Model Simulations of the Large-Scale

Room/Corridor/Room fires

Due to the high cost of full-scale testing, considerable care must be taken in the design of appropriate test scenarios to be conducted. To determine

the suitability of any chosen large-scale test arrangements, fires involving combinations of the test products were simulated on the computer using the FAST

model to predict conditions in rooms arranged in

different configurations [21]. With the use of such a

predictive model, the number of large-scale tests can be reduced to a minimum by only conducting tests in

the appropriate configurations. As described below,

two different potential room/corridor/room configurations and three doorway opening sizes to the

outside were explored. These computer simulations

would not only be used to visualize the impact of the

FR additives on the fire development in the large

scale, but also proved essential in rejecting inadequate

test geometries.

4.1 PRODUCT ARRANGEMENT A AND ROOM

CORRIDOR CONFIGURATION A

Initially, the computer simulations were done for the

product arrangement A shown in Figure 24 with the

room-corridor configuration A indicated in Figure 25.

A 50 kW diffusion burner, using natural gas and positioned against one side of the chair, served as the fire

initiation source. An auxiliary burner in one back cor- ner of the burn room served as a possible fire source

prior to ignition of the products. A 2 m wide by 1 m

high doorway was chosen between the corridor and

the outside. The low height was intended to help trap

combustion gases in the corridor and to force these

gases into the side target room. The broad width was

used to ensure adequate fresh air for combustion.

4.1.1 NFR PRODUCTS

For the NFR items arranged as in Figure 24, data

from the Furniture Calorimeter predicted that chair T

would ignite upon exposure to the 50 kW burner

flames, and flame spread across the burning chair

would reach the cables D and circuit board C by 175

s. At about 200 s later (burn time of 375 s), the circuit

board and cables would ignite and flames would contact the adjacent television cabinets H. After 75 s, item H would ignite and become fully involved by

another 125 s (burn time of 575 s), by which time

flames would be contacting the business machine cabinets F. Item F would ignite in another 75 s (burn time

of 650 s). The FAST computer fire model [21] uses mass loss rates as the basic input data describing the

fire. For the NFR items arranged as in Figure 24, the

presumed mass loss rates for this case are shown in

Figure 26. A composite mass loss record is shown in

Figure 27. This consumption history was used in the

FAST model program [21] to predict the fire development in the room/corridor/room spaces.

4.1.2 FR PRODUCTS WITH AUXILIARY BURNER

With the FR products, the Furniture Calorimeter

tests showed that chair S would not support continued

flame spread under free-burn, ambient conditions.

Data from the Cone Calorimeter indicated that the

flame spread threshold for chair S was about 10

kW/m2

, and that only about 20% of chair S would be

consumed under that flux environment. For the model

simulation it was desired to set the heat release rate from the auxiliary burner such that flame spread

would be sustained in chair S. Such an auxiliary source of heat might be expected to occur in any

number of realistic scenarios. If such additional heating were not included, however, it is likely that the

large-scale results could show no sustained flame

propagation at all. A finding of this nature would not,

then, be taken as a conservative, useful scenario.

Based on earlier data on fire buildup in well35
36 MODEL SIMULATIONS OF THE LARGE-SCALE ROOM/CORRIDOR/ROOM FIRES

insulated rooms [22] and on the fact that the actual

burn room surfaces are not as well insulated, a total heat source of 300 to 350 kW in the room was estimated to be needed for achieving a 10 kW/m2 exposure

in the lower part of the room and for sustaining flame

spread over chair S. To verify this, a preliminary ex- periment was performed in the burn room with a gas

burner in one back corner operating at 300 kW, and

the 50 kW ignition source burning under one edge of

a single, horizontal chair S cushion. It was observed

that flame spread was sustained and took 240 s to tra- verse the top surface of the cushion.

In the computer simulation fire, a 250 kW rate was

used for the auxiliary burner, a 50 kW rate was used

for the ignition burner, and 20% (or 2.38 kg) of chair

S was assumed to be consumed based on data from the

Cone Calorimeter. It was assumed further that its burning history curve would have a similar shape as

that for the NFR chair T. As for the other FR products, cable K did not burn readily in the Furniture

Calorimeter and was expected to act as a fire barrier to the TV cabinets G and the business machine housings

A. The circuit board material L was not expected to contribute significantly to the fire. Mass loss rate curves corresponding to these set of assumptions are shown in Figure 28.

4.1.3 MODEL PREDICTIONS FOR

CONFIGURATION A

The computer predictions for both NFR and FR

scenarios indicated that there might not be enough hot

combustion gases entering the side target room, for

adequate resolution of the toxicological differences in

the combustion gases between burn tests of the NFR

versus FR products.

4.2 PRODUCT ARRANGEMENT B AND

ROOM/CORRIDOR CONFIGURATION B

To create a scenario where a measurable flow of

combustion gases would go to the target room, an

alternative geometrical arrangement was devised.

This was room/corridor/room configuration B, shown

in plan view in Figure 29, in conjunction with the

product arrangement B, shown in Figure 30. Two possible doorway openings from the target room to the

outside were considered. One case used a typical

doorway 0.76 m wide and 2.03 m high. In the other

case, an undersized 1.0 m wide 1.07 m high doorway was used to trap more heat and combustion gases in

the target room.

Analysis of the Furniture Calorimeter free-burn

data for the NFR items indicated that the television

cabinets H would be burning at their peak rates at the

time when chair T would be entering a vigorous burning period, at about 150 s, leading to probable

flashover at about the same time if these items were

burning in a room. For calculational purposes, items

C, D, and F were assumed to be exposed to flames at 150 s, and behave like their performances in the Furniture Calorimeter. In the computer simulations with

this furniture arrangement, production of CO, C02 , and oxygen depletion, using the data from the Furniture Calorimeter were also included. For simplicity, an average value of 1.6 kg C02 per kg product con- sumed was used. A value of minus 2.1 kg 02 per kg

product consumed (based on the approximate value of

13.1 MJ for each kg 02 consumed in a fire, and an av- erage Ahc value of 28 MJ for each kg NFR product

burned) was also used. Production of C02 from the

gas burners was expressed in terms of the per-unit

mass of equivalent products burned by the burners

based on a heat of combustion of 28 MJ per kg of

products. The per-unit-mass generation of CO for

each item as measured in the Furniture Calorimeter was used as given in Table 7. In those cases where

Furniture Calorimeter data were not available, the

corresponding data from the Cone Calorimeter were

used. The mass loss and the production of CO for

each item were then used to generate composite

histories for mass loss and CO production for input to the computer model. Figure 31 shows the mass loss

rates presumed to occur for this scenario.

Computer predictions indicated that the undersized

target room doorway to the outside resulted in the fire being limited by lack of oxygen early in the run, with

predicted concentrations of CO as high as 6900 ppm

in the target room. With the larger doorway opening, an upper layer temperature of about 600 °C, a value indicative of room flashover, was achieved at about 150

s. Peak CO levels of 3500 ppm in the target room were

predicted. Based on the findings that flashover conditions in the burn room and that high concentrations of

CO in the target room were theoretically possible, it was decided by FRCA to use arrangement B with a

typical doorway in conducting the large-scale ex- perimental work.

4.3 WORST CASE SCENARIO FOR PRODUCT

ARRANGEMENT B AND ROOM/CORRIDOR

CONFIGURATION B

4.3.1 NFR PRODUCTS

In the predicted scenarios in the preceding section,

the burning rates for each individual item were taken

directly from the furniture calorimeter data. Under
Worst Case Scenario for Product Arrangement B and Room/Corridor Configuration B 37

such free-burn conditions, interactions between

materials or between materials and heated room sur- faces are assumed to be negligible. Using the early

time rate of heat release histories from the Furniture

Calorimeter tests for chair T and television cabinets

H, prior to fire involvement of the remaining products,

it can be shown that the summation of the rates from

the 50 kW burner, T, and H would be about 0.6 MW

at 100 s. This rate, when combustion enhancement

from the effect of the enclosure was considered, could

lead to flashover. As a worst case scenario and to ac- count for combustion enhancement, it was assumed

that flashover would occur and that all of the items

would be burning at their peak open burn rates by 100

s. These considerations along with the actual CO and

C02 production per item (rather than an approximate

average 1.6 kg C02 per kg product burned) were used

in the generation of the composite histories for mass

loss, CO and C02 for input to the computer model.

Figure 32 shows the mass loss rates assumed for this case, when no auxiliary burner is used. Figure 33

gives the estimated mass loss rate for the case of using

the auxiliary burner. Note that only the time sequence

is different, since the first 300 s comprise only the

heating from the auxiliary burner, without the ignition

burner being turned on. That is, the ignition burner is turned on at t = 0 in Figure 27, and at t = 300 s in

Figure 33. Since worst case burning rates were already

assumed for the case without the auxiliary burner, no

further rise in burning rates due to the heating of the

auxiliary burner was added to produce Figure 33.

4.3.2 FR PRODUCTS

4.3.2.1 Without Auxiliary Burner

With the FR items, the television cabinet G and

chair S would ignite upon exposure to the ignition

burner flames. However, chair S would not be ex- pected to sustain fire spread beyond the region of contact with the burner flames. Cables K and circuit

board L would not burn much, and the cables K would

act as a fire barrier to the business machine housings

A. Thus, for calculational purposes, only the 50 kW

burner and item G would be contributing to the fire buildup. Figure 34 shows the mass loss rates for this

case.

4.3.2.2 With Auxiliary Burner

The television cabinets G would ignite almost immediately upon flame contact with the 50 kW burner.

Data from the Furniture Calorimeter indicated that

these cabinets would produce up to 180 kW. Earlier

work indicated that a total of 300 to 350 kW would

result in a room thermal flux environment whereby

flame spread would be sustained in chair S. Thus, the

auxiliary burner need only generate 120 kW to achieve

this environment.

In the computer simulation, 120 kW would be

prescribed for the auxiliary burner 'and chair S would

be assumed to burn in the manner described earlier

under the influence of the auxiliary burner. Based on

results of the flame spread experiment with the single

chair S cushion discussed earlier, the flames would be

expected to traverse the chair surface and to contact

the cables K in about 240 s. The Furniture

Calorimeter data indicated that the cables K did not

burn significantly until after 200 s following flame

contact. Therefore, for calculational purposes, the

cables were assumed to contribute to the fire at 440 s. An examination of the Furniture Calorimeter mass

loss data and heats of combustion from the Cone

Calorimeter for the FR products together with the

probability that only items G and S would be significantly involved resulted in a composite mass loss

history with a heat of combustion of about 13.6 MJ per

kg of products burned. This resulted in a value of 0.72

kg C02 produced for each equivalent kg of products

burned by the gas burner and in minus 1.0 kg 02 for

each kg products consumed in the room fire. These

considerations along with the actual CO and C02 production per item, as determined with the Furniture

Calorimeter, were used as input to the computer

model. Figure 35 gives the mass loss rates presumed

for this case.

4.3.3 MODEL PREDICTIONS WITH

CONFIGURATION B

Model predictions of the average upper layer temperature and the CO concentration in the burn room

for the NFR products with and without the auxiliary

burner are given in Figures 36 to 39. When 120 kW

was prescribed for the auxiliary burner, the time for

the rate of heat release of the burning products to reach 0.6 MW under open burn conditions (a value

assumed, above, to lead to room flashover when the

products were burned in a room) shortened by only 10

s. Thus, the prediction curves for this case, indicated

in Figures 31 and 33 can be seen to shift by about the

same time interval (taking into due account the 300 s difference in the time axes).

Model predictions as above for the FR products,

with and without the auxiliary burner, are indicated in

Figures 40 to 43.
38 MODEL SIMULATIONS OF THE LARGE-SCALE ROOM/CORRIDOR/ROOM FIRES

4.4 USE OF THE MODEL PREDICTIONS IN THE

DESIGN OF LARGE-SCALE TESTS

The model simulations in this report are one of the

first use of predictive fire modeling in the design of

full-scale fire tests. They proved an invaluable tool in

selecting the best physical configuration for the test

facility used in the experimental program. Based on

these computer predictions for the NFR and FR products using arrangement B and the room-corridor configuration B with the larger doorway opening, FRCA

adopted the same arrangement and configuration for

the experimental program.

120 kW

auxiliary burner

Circuit board panel-

-50 kW burner

Chair^

CablesTelevision cabinets

Business

machine

cabinets

SCALE

1 m

2 ft

PLAN ELEVATION

Figure 24. Arrangement A of test items in the burn room.

Corridor Burn Room

Target

Room

SCALE

5 ft

Figure 25. Plan view of large-scale test arrangement A.
480 600 720

TIME (a)

960 1080 1200

Figure 26. Mass loss rate for NFR furnishing arrangement A and

room-corridor configuration A without the auxiliary burner.

25 r

Flame contact,

C and D

C and D ignite

Flame contact, H

,-Flame contact, F

rF Ignites

200 300 400 500 600 700

TIME FROM BURNER FLAME EXPOSURE (s)

800 900

Figure 27. Composite mass loss history for NFR furnishings.

39
J I I i_l 1 1 1 L 0 120 240 360 480 600 720 640 960 1080 1200

TIME (S)

Figure 28. Mass loss rate for FR furnishing arrangement A and roomcorridor configuration A with the auxiliary burner.

Burn Room

Corridor

Target Room

SCALE

.1m.

Gas Analytical

Measurements

Animal

Chambers

©Thermocouple tree ©Fluxmeter

[GjGas probe

©Pressure probe

Figure 29. Plan view of large-scale test arrangement B.

40
.050

.045

.040

„ .035

* .030

— BURNER — T — H - o - F - C

<r .025

inW

o

-J .020

in

(A* .015

.010

.005

.000

-i-

.j—

i

120 240 360 480 600 720

TIME (8)

840

I

' 960 1080 1200

Figure 31. Mass loss rate for NFR furnishing arrangement B and

room-corridor configuration B without auxiliary burner.

41
.050

.048

.040

~ .035

at - .030

<

a.

in

ino

inin<

.025

.020

.015

.010

.005

.000

- - ¥ * f

~—JL 1

— BURNER — T — H

.- d

-- F - C

120 240 360 480 600

TIME (8)

720 640 960 1080 1200

Figure 32. Accelerated mass loss rate for NFR furnishing arrange- ment B and room-corridor configuration B without the auxiliary burner

.050

.045

.040

- .035

* .030

a. .025

in

ino

•J .020

in

in* .015

.010

.005

.000

L

"1

— BURNER — T — H

- o

-- F - C - AUX BURNER

120 240 360 480 600 720

TIME (s)

640 960 1080 1200

Figure 33. Accelerated mass loss rate for NFR furnishing arrangement

B and room-corridor configuration B with the auxiliary burner.

42
.050

.045

.040

.035

.030

.025

.020

.015

.010

.005 K

.000

L

-I L. J_ _1_ 120 240 360 480 600 720

TIME (s)

JL

BURNER

6

640 960 1080 1200

Figure 34. Mass loss rate for FR furnishing arrangement B and roomcorridor configuration B without the auxiliary burner.

.050

.045

.040

.035

.030

.025

.020

.015

.010

.005

.000

r- i

r—f-| !

BURNER

6

H s

KAUX BURNER

_i_ 120 240 360 460 600 720

TIME (•)

840 960 1080 1200

Figure 35. Mass loss rate for FR furnishing arrangement B and roomcorridor configuration B with the auxiliary burner.

43
1500 i

1 1 1 1 1 1 —i r

0 180 360 540 720 900 1080 1260 1440 1620 1800

TIME (s)

Figure 36. Model prediction and test result curves for the average upper layer temperature in the burn room/corridor/target room for NFR

furnishings without the auxiliary burner.

180 360 540 720 900 1080 1260 1440 1620 1800

TIME (s)

Figure 37. Model prediction and test result curves for carbon monoxide in the burn room/corridor/target room for NFR furnishings without

the auxiliary burner.

44
oo

UJ

QC<

rr

111 O.5

ID

1500

1350

1200

1050

900

750

600

450

300

150

Ignition of first item

between 300 and 302 s roximate upper

(diffusion flame

temperature)

1 1 1

Test NX1 —^— Burn Room

Corridor

Target Room

Model

Burn Room

Corridor

Target Room

180 360 540 720 900 1080 1260 1440 1620 1800

TIME (S)

Figure 38. Model prediction and test result curves for the average up- per layer temperature in the burn room/corridor/target room for NFR

furnishings with the auxiliary burner.

5.0 I

1 1 1 i

1 1 1 i r

4.5 -

Test NX1

4.0 - Burn Room

Corridor

TIME (s)

Figure 39. Model prediction and test result curves for carbon monoxide in the burn room/corridor/target room for NFR furnishings with the

auxiliary burner.

45
1500

1350

1200

1050

6

~ 900

UJ

cc| 750

cc

111 I

600

LU 450

300

150

0

Test F1

Burn Room

Corridor

Target Room

Model

Burn Room

Corridor

Target Room

JL 180 360 540 720 900 1080 1260 1440 1620 1800

TIME (s)

Figure 40. Model prediction and test result curves for average upper

layer temperature in the burn room/corridor/target room for FR furnishings without the auxiliary burner.

5.0

4.5

4.0

<u 3.5

E

j3> 3.0

2 2.5

<

i-2

111 O

z

O

O

2.0

1.5

1.0

0.5

0

Test F1

Burn Room

Corridor

Target Room

Model

Burn Room

Corridor

Target Room

180 360 540 720 900 1080 1260 1440 1620 1800

TIME (s)

Figure 41. Model prediction and test result curves for carbon monoxide in the burn room/corridor/target room for FR furnishings without

the auxiliary burner.

46
oo

lil CC

CC

LU

CL

LU

1500

1350

1200

1050

900

750

600

450 -

300 -

150

—Test FX1a

Burn Room

Corridor —--- Target Room

Model

Burn Room

Corridor

Target Room

180 360 540 720 900 1080 1260 1440 1620 1800

TIME (S)

Figure 42. Model prediction and test result curves for the average up- per layer temperature in the burn room/corridor/target room for FR

furnishings with the auxiliary burner.

5.0

4.5

4.0

<d 3.5

E

2 3.0

2 2.5

<

cc

UJO

z

o

o

2.0

1.5

1.0

0.5

T T T T T T

Test FX1a

Burn Room

Corridor

Target Room

Model

Burn Room

Corridor

Target Room

180 360 540 720 900 1080 1260 1440 1620 1800

TIME (s)

Figure 43. Model prediction and test result curves for carbon monoxide in the burn room/corridor/target room for FR furnishings with the auxiliary burner.

47

Large-Scale Tests

The large-scale burn room/corridor/target room

were designed to be the ultimate validation of the

differences in hazard between the NFR and the FR

components. An actual use environment might be rare where all five of the products studied would show up

in one room. Nonetheless, it was felt that an arrangement where all the NFR or all the FR products are located in one test room would serve best to reveal the

fire hazards expected. In either case, the fire was ex- pected to be dominated by the more flammable products, with smaller, if any, contributions from the less

flammable ones. Thus, the scenario is a challenging

one, since it effectively exposes all the specimens to the fire conditions created by the most combustible

one.

5.1 EXPERIMENTAL

5.1.1 ROOM/CORRIDOR/ROOM CONFIGURATION

The experimental facility is shown in Figure 29 and

comprised a burn room connected to one end of a corridor and a target room at the opposite end of the corridor. A doorway from the target room led into a

large open space over which a3.7m X 4. 9m hood,

having an exhaust flow capacity of about 3 m3 /s, was

used to collect the exhaust from the fire tests. Table

12 summarizes the dimensions of the facility. The

ceilings and walls were constructed with gypsum

board sheathing with a covering of 13 mm calcium

silicate board to assure structural integrity during prolonged and repeated fire exposures. The concrete

floors were covered with 13 mm gypsum board to protect the concrete. The construction materials used

in this test series are given in Table 13 along with

their properties.

5.1.2 ROOM FIRE TEST ARRANGEMENT

The arrangement of test items in the burn room is given in Figure 30. Each set of test items consisted of

a chair, fabricated from four upholstered foam cushions; two television cabinets; two business machine

cabinets; an array of twenty five power cables strung

along a vertical steel ladder; and one circuit board

panel mounted behind the other furnishings. This

basic arrangement was the same for tests on both the

NFR items and the FR ones. A 120 kW auxiliary

natural gas burner in one back corner .of the room

simulated the combustion of additional furnishings in

the room. A 50 kW natural gas burner, positioned

under the television cabinets and in contact with one

side of the chair, served as the ignition source. Seven room fires were performed as follows, in the

given order:

Test Description

Fl FR items, with animals

FXO FR items, with auxiliary burner, no animals

FX1 FR items, with auxiliary burner, with

animals

Nl NFR items, with animals

FXla Repeat of FX1

NXO NFR items, with auxiliary burner, no

animals

NX1 NFR items, with auxiliary burner, with

animals

For the above test numbers F = fire-retarded,

N = non fire-retarded; X = with auxiliary burner,

absence of X = no auxiliary burner; 0 = no animals, and 1 = with animals.

49
50 LARGE-SCALE TESTS

5.1.3 INSTRUMENTATION

The location of all instrumentation used in the test series are summarized in Table 14 with some of the instrumentation also shown in Figure 24. Data were

recorded with an automatic data logging system at a

rate of 120 data channels every 12 seconds.

5.1.3.1 Thermocouples and Pressure Probes

Six thermocouple trees, shown in Figure 29, were

used in this study. These thermocouples were fabricated from 0.51 mm diameter Chromel and Alumel

wires. Differential static pressure measurements were made on the wall surfaces between rooms near the

floor. These pressure measurements between interconnecting rooms together with air temperatures

measured by the interior and doorway thermocouple

trees in the room with the outflow can be used to determine the neutral plane height and mass flow

through the doorway [23]. The thermocouple trees also measured the thermal stratification in the roomcorridor facility. In addition, a 0.51 mm ChromelAlumel thermocouple was used on the ceiling in the

burn room, directly over the test items, to further help

estimate heat transfer to the room boundaries. Two

0.05 mm Chromel-Alumel thermocouples were also

used in the NFR tests near the burn room ceiling to provide fast response temperature readings which

were relatively free of radiation errors for a closer determination of room flashover time (defined here as 600°C air temperature at 0.10 m below the ceiling).

5.1.3.2 Flux Meters

Water-cooled flux meters of the Gardon type were

used on the ceilings and floors of the burn room, corridor, and target room to help characterize the thermal

flux environment in these spaces. In addition, Gardon

type flux meters (pointing upward) were positioned at heights of 0.61 and 1.22 m above the floor in the burn

room to estimate the fluxes, emitted from the hot air

and heated surfaces in the upper portion of the room,

that were received by the test items in the room.

Combustion Gases

Stainless steel lines having a 7.8 mm inside diameter were used to transport 02 , CO, and C02 in the burn

room, corridor, and target room to gas analyzers for

continuous measurement. Oxygen concentrations were monitored with paramagnetic analyzers, and CO

and C02 were measured with infrared analyzers. In

addition, combustion gases from the target room were

routed through a 3.4 m long sampling line to three 200

1 animal chambers where animals were exposed to the

combustion gases and where analytical measurements

of CO, C02 , HC1, HCN, and HBr were taken. These

chambers were located in a closed room adjacent to one side of the corridor. Another 2.8 m long sampling

line to this room carried the combustion products

from the burn room at a rate of 2.9 1/s for analytical

measurements. The gases from both rooms were

returned to the respective rooms. Both sampling lines were initially constructed of glass and

polymethylmethacrylate tubing having a diameter of

51 mm. The first 2 m of the lines protruding into the

rooms were glass, except for the last NFR run which

required stainless steel tubing in the burn room to prevent melting. The animal chambers with their associated filling and exhaust lines and blower fan were

equipment used in a previous study [4]. The filling

times for these chambers in the initial three tests of the

present study were found to be lower than desired. If

it is assumed that a steady state flow of a combustion

gas from the target room entered the animal chamber

and was instantaneously mixed throughout the volume

of the chamber prior to exiting at the opposite end of

the chamber, then the chamber concentration of that

gas can be estimated as a function of its concentration

in the room and the filling rate and duration as fol- lows:

C = j- [I - exp(- Vj/Ve)] (5)

where:

C = combustion gas concentration (mg/1)

m = generation rate of combustion gas (mg/s)

t = chamber filling time (s)

V0 = volumetric airflow through chamber (1/s)

Vc = volume of chamber (1)

Inherent in the above equation is the assumption that

there is no material loss due to surface deposition in

the sampling line and chamber.

Calculated concentrations for a gas using the above

equation, expressed in percent of its concentration in

the target room, are given in Table 15 for filling times

of 60, 120, and 180 s. These estimates confirmed that

the filling rates for tests 1 to 3 were too low. Consequently, a higher capacity blower was used in the subsequent tests 4 to 6. Certain leaks in the chambers and

in the blower line were also found prior to test 7. Resealing of the leaks resulted in different percentage

fill in the chambers for test 7. Table 15 includes the es- timated percent of the room concentration attained in

the chambers for these tests at 60, 120, and 180 s.
Test Procedure 51

5.1.3.4 Smoke

Smoke meters were not used within the burn room;

instead, smoke performance was measured by determining the total amount of smoke collected through

the exhaust hood system; see below.

5.1.3.5 Exhaust Hood Measurements

Temperatures, velocities, oxygen, CO, and C02 concentrations and smoke in the exhaust collection

hood were monitored with the instrumentation listed

in Table 14. These measurements were used to determine the total rate of heat production and to quantify

the production of CO, C02 and smoke from combustion of the test items.

5.1.3.6 Gas Sampling Technique for Large-Scale

Tests (Burn Room)

The same equipment was used for the large-scale

tests as for the previously described Furniture

Calorimeter tests. However, a modification to the impinger assembly was done to provide for continuous

sampling during the burn. The apparatus is diagrammed in Figure 44. With the impingers connected

in parallel, the gases were bubbled through one arm

while the other arm was being replaced with a fresh

impinger. The mass flow through the impingers was

nominally 1 1/min and was verified prior to each test with a laboratory dry-gas meter. The ratio of gases

collected to gases recirculated was nominally 1:173. The impinger solution was 5 mM KOH for the first

test and 10 mM KOH for the remaining tests. Sampling was initiated when the 50 kW natural gas burner was started and stopped when the fire was determined

to be out. The samples were prepared and analyzed as previously described.

5.1.3.7 Gas Sampling Technique for Large-Scale Tests

(Animal Exposure Boxes)

Gas samples from the three exposure boxes were

collected at the nose levels of the animals. The apparatus is diagrammed in Figure 45. The flow was generated with a sampling pump and regulated with individual rotameters for each box. The flow rates (30-45

ml/min) were verified with a soap bubble meter before

each test. Samples were collected for the duration of

10 to 30 minutes during the animal exposures.

For the first test one 3 ml microimpinger with 5 mM

KOH was used. Because of a low pH value, the next

test used two 3 ml microimpingers in series with 10

mM KOH. The third test used two micro impingers in

series with 100 mM KOH. The remaining tests used

two, tared 30 ml impingers in series containing approximately 25 ml of 10 mM KOH. The microimpingers were separated by a 25 mm PTFE filter with a 0.45 nominal porosity. The 30 ml impingers were separated with the same diameter PTFE filter with the

same nominal porosity. At the end of the test the

microimpinger solutions were quantitatively trans- ferred and diluted to 5ml with 5ml KOH. The 30 ml

impinger solutions were transferred to plastic containers. The filter with the collected soot and aerosols was

added to the first impinger solution in all cases.

5.1.3.8 Animal Exposures

Three animal exposure chambers identical to those

used in the NBS Toxicity Test Method were placed one on top of the other in a room located outside the

room-corridor-room arrangement (Figure 29). A

glass sampling line (51 mm in diameter and 3.4 m

long) was located such that smoke was pulled from a position 0.34 m from the ceiling, 0.30 m from the east wall and 0.50 m from the south wall of the target room. The smoke was continuously transported

through all three animal chambers with no animals

present until the time designated for the animal exposures. Each chamber was equipped with gas analyzers

for CO, C02 , and 02 as well as a thermocouple and an

individual sampling port for HCN. A strip chart

recorder was set up to continuously monitor the CO in

one of the animal exposure chambers (the last to be

closed) and this recording was used to determine the

time that the sampling and return lines to each chamber were closed. The times that the chambers were

closed and the estimated CO concentration at that time

are given in Table 16. After the chamber was closed,

the animals were inserted such that only their heads were exposed to the steady-state concentration for 30

minutes. In each experiment, three sets of six rats were exposed sequentially to different fractions of

smoke drawn from the target room. The animals were

watched during the exposures to determine the time of

death and the survivors were examined following the

30-minute exposures for righting reflexes, eye reflexes, nose and mouth discharges, and respiratory effects. All surviving animals were kept and weighed daily for

at least 14 days.

5.2 TEST PROCEDURE

In all of the tests, a 50 kW natural gas diffusion

flame burner was used as the fire initiation source. A

dry test meter was used to meter in the natural gas flow

to the burner. The top side of the burner, which had a
52 LARGE-SCALE TESTS

porous ceramic surface with nominal dimensions of

180 X 250 mm, was positioned 13 cm above the floor,

against the side of the chair, and directly under the

television cabinets as shown in Figure 25. In five tests, a 120 kW auxiliary diffusion flame burner was used in

one back corner of the burn room. The top side of the

burner, which had a 0.30 x 0.30 m porous ceramic

surface, was placed 0.30 m above the floor. Both the

fire initiation source and auxiliary burner used small

pilot flames over their top surfaces for remote ignition.

Tests were performed with the data recording

system turned on for about 120 s prior to ignition of

the fire initiation source or of the auxiliary burner

when it was used. In all of the tests, the 50 kW fire ini- tiation source was left on for 200 s, and the fire was

allowed to run for 1800 s. The auxiliary burner, when

used, was turned on for 300 s prior to ignition of the

50 kW source and was left on for 2100 s.

5.3 LARGE-SCALE TEST RESULTS

5.3.1 DATA FROM EXHAUST STACK INSTRUMENTS

Figure 46 shows the basic rate of heat release data

from the two tests without the auxiliary burner, Nl

and Fl. Figure 47 gives the corresponding data for the

remaining tests, which all used the auxiliary burner.

The total mass flow rates of CO are given in Figures

48 and 49, while C02 flows are shown in Figures 50

and 51. Smoke production results are given in Figures

52 and 53.

5.3.2 DATA FROM ANIMAL CHAMBERS

In the total of seven large-scale tests, two (FXO and

NXO) were performed without any animals to monitor

the gas concentration and temperatures in the animal

exposure chambers. The first three tests were with FR

materials and the rates of the gas flow through the animal chambers were such that the highest levels of CO

reached were approximately 3200 ppm. After these

three tests, the pumps were changed so that the gas

flow rates were higher and the concentration of CO in

the animal chambers more closely resembled those in

the target room. The initial plan was to close the animal chambers

when the CO concentrations were approximately

2000, 4000, and 6000 ppm. Any deaths at 2000 and

4000 ppm of CO would indicate the presence of additional toxic gases. Table 16 indicates the filling times

and the CO levels estimated by the strip chart recorder

in each animal chamber when it was closed. Table 17

shows the actual concentrations of CO and the other

gases that were monitored.

In test Fl, the chambers were closed at estimated

CO concentrations of 3000, 5000, and 7000 ppm.

However, the calibration of the CO strip chart re- corder was incorrect and the chambers actually were

closed with approximately half of the estimated CO

concentrations. As seen in Table 17, the N-Gas Model

prediction values based on the interaction of the concentration of monitored gases in the three sets of animal exposure chambers ranged from 0.15 to 0.66. If

these gases were the only ones contributing to the toxicity of the atmospheres, no animals would be ex- pected to die and, in fact, no lethalities were observed.

In test FXO, the strip chart CO recorder was cor- rected so that the animal chambers could be closed

when the concentrations of CO were closer to the

desired values. However, because of low animal chamber filling rates, the CO concentrations in the chambers leveled off before the maximum desired level

could be reached. The animal exposure chambers

were closed at such times that the measured average

CO values in the chambers were 1600 ppm, and 2770

ppm, which was the highest attainable. The third

chamber was then closed at a later time (almost 20

minutes following ignition) in order to try to obtain

combustion products from some of the materials that

would become involved later in the fire. Under these

filling conditions, the N-Gas Model prediction values

based on the monitored gases ranged from 0.51 to 0.78. Since this was a test without animals, the correctness

of the N-Gas Model prediction could not be checked.

Test FX1 was a repeat of FXO except that animals were included. The exposure chambers were closed at times which resulted in average chamber CO levels of

1750, 2530, and 1060 ppm (the last chamber was

closed at a much later time in the exposure to obtain

some of the combustion products from the materials

that became involved in the fire at that later time). The

N-Gas Model prediction values for these three chambers ranged from 0.41 to 0.82; no animals were ex- pected to die and none did.

Experiment FX1 was repeated and called FXla. In

this test, the pumps were changed so that the animal

exposure chamber atmospheres more closely resembled that of the target room. In this experiment it was

possible to close the animal exposure chambers at higher CO concentrations— average CO concentrations in the three animal exposure chambers were

2400, 4750, and 6000 ppm. The N-Gas Model prediction values were 0.70 with no deaths, 1.29 with 5/6

deaths, and 1.65 with 6/6 deaths. These results (deaths were observed only when the N-gas Model prediction

value was above 1.0) indicate that no gases other than

those monitored in these experiments were contribut-
Comparison Between Small-Scale and Large-Scale Toxicity Findings 53

ing to the toxic atmospheres (i.e., these atmospheres were not unusually toxic). The determination of ex- treme toxic potency (concentration of material decomposed which produces lethal conditions) was not possible under these experimental conditions since

multiple materials were being burned, mass loss was

not monitored, and knowledge of what materials were

involved in the fire at what times was not known.

All of the NFR material tests were conducted with

the higher gas flow rates. However in test Nl, the

pumps to the animal exposure chambers were not

turned on until almost 3 minutes after ignition, at which point the chambers filled very rapidly. The bottom chamber was closed at 3.5 minutes after ignition,

giving an average CO concentration of 7140 ppm. The

middle chamber was closed at 4 min, giving 8880

ppm, while the top chamber was closed at 6.5 min and

showed CO > 10,000 ppm. The average gas concentrations in the top chamber are not given in Table 17,

since the animal exposure chamber leaked. In the

middle chamber, the N-Gas Model prediction value

was 4.10 or approximately four times the lethal concentrations. An interesting observation which needs

more research to substantiate is that the animals died

in approximately 1/4 the 30-minute exposure time. In other words, if the N-Gas Model prediction value was

1.0, one would expect half of the animals to die in the

30-minute exposure period. Perhaps if the N-Gas

Model prediction value is 4.1, one could predict that

the animals would die in (1/4.1) x 30 min or 7.3 min.

In the middle chamber, the mean time to death was

6.5 ± 0.15 min. In the bottom chamber, the N-Gas

Model prediction value was 3.16 or three times the

lethal concentration of gases. As expected, all the animals died. If the time factor holds, the predicted time

of death would have been 9.5 minutes. In actuality, the

mean time to death was 10.2 ± 0.1 minutes. Since in

the middle chamber, the animals died slightly earlier

than expected and in the bottom chamber, they died

slightly later than expected, it appears as though the

gases generated in this exposure are probably responsible for the lethalities that occurred and there is no

need to presume other gases are involved.

In experiment NXO, no animals were exposed. The

bottom chamber was closed at 7 min 45 sec after ignition, giving an average CO concentration of 3400

ppm. The middle chamber was closed at 8:10, but was

later found to leak. The top chamber was closed at 8:30, giving a concentration of 9150 ppm. The N-Gas

Model prediction values for the bottom and top chambers were 3.11 and 3.62. These values would predict

that if animals had been exposed, they would have

died.

Experiment NX1 was the repeat of NXO with animals. In this experiment, the bottom and middle animal exposure chambers were closed at lower estimated CO values and the top chamber was not closed

until later in the experiment to try to include the combustion products from the materials that would be involved during this later period of time. The actual av- erage CO concentrations were 1820 ppm in the bottom

chamber, 4490 ppm in the middle chamber and 1160

ppm in the top chamber. Since no animals died in the

bottom chamber with an N-Gas Model prediction

value of 0.97, there is no need to presuppose the involvement of gases other than those monitored. In the

middle chamber, the N-Gas Model prediction value

was 2.82 and all the animals died, as expected. If the

above discussion on use of the N-Gas Model to predict

time to death is valid, then the animals should have

died 10.6 minutes into the exposure. The actual mean

time to death was 9.3 ± 0.6 minutes which indicates

that the deaths that occurred are probably attributable

to the gases that were examined. The top chamber,

although filled at the later time, did not produce any

deaths at the N-Gas Model prediction value of 0.62,

indicating that other gases could not be contributing to more than 38% of the toxicity. But since the bottom

chamber had no deaths at an N-Gas value of 0.97, the

likelihood of other gases being involved is low.

For all tests, a summary of the total integrated value

of the gas exposure is provided in Table 18. The results are expressed as ppm • min.

5.3.3 DATA FROM OTHER OBSERVATIONS

The amount of specimen mass consumed was determined by examining the test residue after the test. These data are given in Table 19. Test Fl, the FR test where the auxiliary burner was not used, resulted in

only a very small amount (6.0 kg) of combustibles being consumed. Thus, as was expected in the test formulation, it did not achieve the goal of providing for

substantial fire involvement to the furnishings. Consequently, the data from test Fl will not be used in

assessing the performance.

5.4 COMPARISON BETWEEN SMALL-SCALE AND

LARGE-SCALE TOXICITY FINDINGS

5.4.1 SPECIES YIELDS

Direct LC50 comparisons between the bench-scale

and the large-scale findings would be the simplest

basis for comparison. Unfortunately, due to the ex- pense involved, complete bioassay studies, leading to an exact LCS0 value, could be done in neither series of

tests. The main question, however— do the test conditions in the bench scale accurately predict the evolu-
54 LARGE-SCALE TESTS

tion of toxic gases in the large-scale environment?— can be answered by some available data.

Before this question is asked, it is appropriate to consider how well the less-than-room-scale measure- ments correlate amongst themselves. For this purpose,

one can compare the species yield data for CO, C02 , HC1, HBr, and HCN, as obtained in three devices:

• the Cone Calorimeter

• the Furniture Calorimeter

• the NBS combustion toxicity apparatus

Table 20 gives this comparison. Note that, in all cases, the measurements referred to are made after the

tip of the flame. Thus, they represent the toxic effects

of cooled combustion products and are not values in

the flame zone (which would not be relevant to the

study of toxic fire hazards).

The comparison for CO shows that, in those cases where the Cone Calorimeter data show very low

values, the values obtained from the NBS combustion

toxicity apparatus are typically higher and are closer

to the values obtained in the Furniture Calorimeter.

For the materials producing higher yields of CO, no

systematic differences between data from the three devices are evident, although scatter is, in some cases, high.

For C02 , the data from all three devices are generally in good agreement, with possibly a slightly better

agreement obtained between the Cone Calorimeter

and the NBS combustion toxicity apparatus than between the Furniture Calorimeter and the other two devices.

For the acid gases, the number of tests where such

measurements needed to be taken were small, thus statistically valid conclusions are difficult to make. For

HCN, based on three materials where data from more

than 1 system were available, there is scatter of approximately a factor of 3. Part of the explanation lies

in the small amount of HCN being produced. Another

reason for differences in these two measurements

could lie in the fact that different measurement techniques (gas chromatography and ion chromatography) were used. GC measurements will give only gaseous

HCN yields. With the ion chromatography technique,

however, a fraction of any HCN which is adsorbed

onto soot particulates could be desorbed and included

in the reported measurement.

For HC1, in the two cases where measurements

from different systems were available, the results

agreed very closely.

For HBr, the values recorded in the NBS combustion toxicity apparatus are substantially smaller than

those obtained from either the Cone Calorimeter or

the Furniture Calorimeter. Since there is no reason to presume that any greater losses would occur in the

NBS combustion toxicity apparatus than in the other

devices, the cause of this difference is not apparent.

The hydrogen halide values even though showing good

agreement for HC1 and poor agreement for HBr, are not significant in either case from a toxicological point

of view. That is, the contribution of these gases to the total toxicity was very slight for all the materials

studied.

5.4.2 FRACTION OF TOXICITY ACCOUNTED BY CO

Another measure of the similarity or dissimilarity of

the combustion environments associated with different

tests is whether the fraction of the total toxicity ac- counted by CO is similar. If such ratios are similar for

two tests, then it can be concluded that toxicity predictions based on data from one test are reasonably applicable to predicting the performance in the second

test. The [CO toxicity] /[total toxicity] ratios were determined separately for the bench-scale NBS combustion toxicity apparatus and for the large-scale roomcorridor-room tests, and are shown in Tables 21 and

22, respectively. Since both the bench-scale and the

large-scale measurements, indicate that once CO,

C02 , 02 , HCN, HC1, and HBr are accounted for, significant additional toxic agents do not need to be invoked, the total toxicity figure can be derived from the

measurements of these six gases. This is done on the

basis of the equation given with Table 17, and includes

the additional effect of C02 in potentiating CO action.

By contrast, "CO toxicity" values are defined simply

as: _ . . [CO] C0 t0X1Clty =

LC50 (CO)

For the NFR bench-scale tests, Table 21 shows that

CO accounts for 17 to 44% of the total. In comparison, Table 22 shows that the large-scale NFR tests produced a range of 27 to 33%. For the FR products,

the bench-scale range was 45 to 75 % , while the largescale range was 44 to 54%. The agreement is highly

encouraging, and suggests that the effects of differing

combustion conditions do not manifest themselves as

preferential evolution of the major toxic agents in the

different scale tests. Even though CO yields are substantially underestimated by the NBS Combustion Toxicity Test (Table

26), it is not contradictory to observe that the fraction

of toxicity accounted by CO is roughly similar. The

differences in the two situations can be largely attributed to differences in C02 and 02 levels not being the same. This happens since the dilution flows in the

large-scale test are governed by both the geometry and
Comparison Between Computer Model Predictions and Actual Large-Scale Results 55

the burning rates, and are not fixed as in a closed-box

toxicity test method.

5.4.3 COMBUSTION PRODUCTS OF EXTREME

TOXIC POTENCY

The presence, or absence, of extreme toxic potency was tested primarily using the NBS combustion toxicity test apparatus. None of the specimens, either

NFR or FR were considered to show extreme toxic potency. In the large-scale tests, a corresponding evaluation

of the toxicity of the combustion products in units of

mg/1 could not be done since the environment was not

a closed system. A reasonable, if somewhat indirect,

assessment for the question of extreme toxicity is determined as follows. The results in the section below

show that unusual toxic potency is not observed.

Therefore, if extreme toxic potency were to occur, it would have to be because of the excessive amount of

the known gases already being measured. The results

in Tables 18 and 27, however, show that, compared to the NFR products, the FR products produced lower,

not higher, quantities of the toxic gases monitored.

5.4.4 COMBUSTION PRODUCTS OF UNUSUAL

TOXIC POTENCY

The animal data presented in Table 17 suggest that

the 6-gas model is a reasonably complete representation of the toxic species encountered, and that unusual

species are not active, at least in any major way. The

data for NFR products show that at a 6-gas prediction

value = 0.97 no animal deaths were observed; a close

upper bound could not be obtained, but at 2.82 all animals died. For FR items, no mortalities were observed

at a 6-gas prediction value = 0.70, while 56 deaths were observed at 1.29.

5.5 COMPARISON BETWEEN COMPUTER

MODEL PREDICTIONS AND ACTUAL

LARGE-SCALE RESULTS

Some comparisons between the computer predictions and the experimental findings for the NFR and

FR products are also given in Figures 36 to 43. With

regard to the average upper layer temperature for the

FR furnishings without the auxiliary burner (Figure

40), the chosen model scenario predicts higher temperatures in the burn room than were actually

achieved in the large-scale tests. In this test (Fl) the

model predicted that the upper layer temperature

would reach almost 300 °C, but the actual temperature

reached was only about 170°C. In all of the large-scale

tests, with or without the auxiliary burner or using

NFR or FR furnishings, the same result is found. This

result is true not only for the burn room, but also for

the corridor and target room.

Like all of the current zone-based fire models, including the FAST model [21], the over prediction of

upper layer temperature is not surprising. Upper layer

temperatures are typically over-predicted by these

models. Too hot an upper layer may be caused either

by over-prediction of the heat entering the layer from

the fire plume, or by under-prediction of the heat lost

from the layer by radiation, conduction, or convection. In FAST, like other contemporary models, mixing occurs only at the vents between rooms and no

heat is lost by radiation to the lower layer. While the

temperature of the lower layer may be important when

considering the effect on occupants and equipment,

currently there cannot be a good prediction, due to the

assumption in the model of no radiative heating and no

mixing into this zone (except at the vents). Thus, the

lower layer temperature is correspondingly underpredicted by the model. As the models become more

sophisticated, these simplifying assumptions are being

removed. In a newer version of FAST, the lower layer can be heated via radiation and mixing. Improved

comparability of layer temperatures in another series

of tests was noted by Jones and Peacock [24]

In regard to the carbon monoxide content in the

rooms, the model scenario predicts less than is actually produced. For instance, the curves in Figure 41

for FR furnishings without the auxiliary burner indicate a predicted CO concentration in the burn room

of ca. 0.7 volume % whereas the actual CO content was ca. 1.1 volume % . In the case of the NFR furnishings, the actual CO values are more than twice as great as the model predicts, as can be seen in Figures

37 and 39. Since all the inputs to the model on burning

rates and CO production for the individual burning

items came from free burn data, the effects of vitiated

burning are not taken into account. Without sufficient

oxygen for complete burning, higher CO concentrations are expected.

As an overall assessment of the usefulness of the

model predictions, several key points are obvious.

First, the modeling exercise reported herein represents

one of the first uses of predictive fire modeling in the

design of large-scale tests. The choice of the final

design for the room/corridor/room test facility was

greatly simplified by the use of the model, eliminating

alternative design options without costly construction

and testing. Secondly, the choice of the input parameters for the model is critical in providing meaningful

model outputs. Significant care must be taken in the use of free burn data for multiple burning items to ac-
56 LARGE-SCALE TESTS

curately model the ignition and burning of more than tions underlying the design of the predictive model to one item in an enclosure. Finally, the model user must be able to assess the meaning of the outputs from the

understand the limitations and simplifying assump- model.

table 12 Dimensions of Room/Corridor/Room

Large-Scale Test Facility.

Location Dimensions (m)

Burn room 2.44 W X 3.69 L x 2.44 H

Burn room doorway 0.76 W X 2.01 H

Corridor 2.44 W X 3.69 L x 2.44 H

Corridor doorway 0.76 W X 2.02 H

Target room 2.44 W X 4.60 L x 2.44 H

Target room doorway 0.76 W X 2.03 H

table 13 Construction of Large-Scale Test Facility.

Location Material

Thickness

t (mm)

Density

e (kg/m3

)

Heat

Cap.

CP (kJ/kg-°C)

Thermal

Cond.

k

(W/m-°C)

Ceiling and

Walls

calcium

silicate board12.7 720 1.3 0.12

Floor gypsum

board

12.7 930 1.1 0.17

table 14 Location of Instrumentation.

I. Room-Corridor

A. Thermocouples

Tree 1 in bum room—ten 0.51 mm thermocouples at 0, 0.15, 0.60, 0.91, 1.23, 1.52, 1.83, 2.13, 2.30, and 2.44 m above floor

Tree 2 in burn room doorway—ten 0.51 mm thermocouples at 0.15, 0.30, 0.61 , 0.76, 0.91 , 1 .07, 1 .22, 1 .37, 1 .52, and 1 .83 m above

floor.

Tree 3 in corridor—twelve 0.51 mm thermocouples at 0, 0.15, 0.66, 0.97, 1.11, 1.23, 1.42, 1.57, 1.89, 2.03, 2.15, and 2.44 m above

floor.

Tree 4 in corridor doorway—ten 0.51 mm thermocouples at 0.1 5, 0.30, 0.61, 0.76, 0.91, 1.07, 1.22, 1.37, 1.52, and 1 .83 above floor.

Tree 5 in target room—eleven 0.51 mm thermocouples at 0, 0.15, 0.60, 0.91, 1.06, 1.23, 1.52, 1.83, 2.13, 2.30, and 2.44 m above

floor.

Tree 6 in target room doorway—eight shielded thermocouples at 0. 1 5, 0.61 , 0.91 , 1 .07, 1 .22, 1 .52, 1 .83, and 1 .93 m above floor. Two 0.05 mm thermocouples, near tree 1 and 0.10 m down from ceiling in burn room. One 0.51 mm thermocouple on middle of ceiling in burn room. One thermocouple in top animal chamber.

One thermocouple in middle animal chamber.

One thermocouple in bottom animal chamber.

B. Static pressure probes

Pressure probes were placed, 0.08 m above the floor, along the wall between the burn room and corridor, between the corridor and

target room, and between the target room and the outside.

(continued)
table 14 (continued).

C. Flux meters

Burn room—three flux meters, 0.61 m from back wall at 0, 0.61, and 1.22 m heights above floor. One flux meter, on floor, 0.61 m

from front wall. One flux meter at the center of the ceiling.

Corridor—one flux meter at center of floor. One flux meter at center of ceiling.

Target room—one flux meter at center of floor. One flux meter at center of ceiling.

D. Gas probes

Burn room—stainless steel probe (6.4 mm inside diameter) for CO, C02 , and 02 at 0.30 m from ceiling, 0.30 m from front wall and

0.48 m from side wall.

Burn room—glass line (51 mm inside diameter and 2.8 m long) for sampling of CO, C02 , HBr, HCI, HCN at 0.30 m from ceiling,

0.30 m from front wall and 0.38 m from side wall.

Corridor—stainless steel probe (6.4 mm diameter) for CO, C02 , and 02 at 0.30 m from ceiling, 0.28 m from back wall and 0.42 m

from side wall.

Target room—stainless steel probe (6.4 mm diameter) for CO, C02 , and 02 at 0.30 m from ceiling, 0.30 m from back wall and 0.29

m from side wall.

Target room—glass line (51 mm diameter and 3.4 m long) for sampling CO, C02 , HBr, HCI, HCN at 0.34 m from ceiling, 0.30 m

from back wall and 0.50 m from side wall.

II. Exhaust Hood

1 —smoke meter 1—probe for sampling CO, C02 , and 02 9—pitot-static probe

9—thermocouples

table 15 Ratio of Gases in Animal Chambers to Target

Room for Specified Times.

Test 1 to 3

cone, in box/ cone, in room (%)

Chamber V(l) V°(l/s) 60 s 120 s 180 s

Top 200 0.411 12 22 31 Middle 200 0.411 12 22 31

Bottom 200 0.411 12 22 31

Test 4 to 6

cone, in box/

cone, in room (%)

Chamber V(l) V°(l/S) 60 s 120 s 180 s

Top 200 1.19 30 51 66

Middle 200 3.91 69 90 97

Bottom 200 3.91 69 90 97

Test 7

cone, in box/

cone, in room (%)

Chamber V(l) V°(l/s) 60 s 120 s 180 s

Top 200 2.88 58 82 93

Middle 200 4.22 72 92 98

Bottom 200 2.88 58 82 93

57
table 16 Animal Exposure Chamber Filling Times and

Estimated CO When Closed.

Test

No.

Fire Retard.

Auxiliary Burner

Animal

Chamber

Filling

Times

(min:sec)

Estimated

COa

(ppm)

N1 Bottom

Middle

Top

2:50- 3:30

2:50- 4:00

2 50- 6 30

3600

6800 > 1 0000 *

NXO - + Bottom

Middle

Top

0- 7:45

0- 8:10

0- 8:30

1100

3400

6000

NX1 + Bottom

Middle

Top

0- 7:35

0- 7:55 0-15:00

1000

4000

1500

F1 + Top

Middle Bottom

0- 3:30

0- 4:45

0- 5:55

3000b 5000b 7000b

FXO + + Top

Middle Bottom

0- 5:00

0- 8:45

0-19:45

2500

3200*

2100

FX1 + Top

Middle

Bottom

0- 9:30

0-13:00

0-41 :00

2000

3200*

1500

FX1a + + Bottom

Middle

Top

0- 8:00

0- 9:05

0- 9:55

2000

4000

6500

concentrations on strip chart recorder used to determine time of ani- mal chamber closure.

b

Strip chart calibrated incorrectly such that CO concentration was actually

half of that estimated from strip chart. 'Maximum level of CO in animal chambers.

58
table 17 Chemical and Toxicological Results in Animal Exposure Chambers Filled During Large-Scale Room Burns.

Gas Concentrations3 Deaths

chamber 6-Gas

Test Fire Auxiliary Animals Animal Temp. CO C02 HCN 02 HBr HCI Within Within & Prediction No. Retard. Burner Present Chamber (°C) (ppm) (ppm) (ppm) (%) (ppm) (ppm) Exp. Post-Exp. Within Exp.

N 1 + Top do b b 7QC b INU O/O O/O + Middle 24 8880 55400 240 13.9 6/6 6/6 4.10 + Bottom 22 7140 39300 200 16.1 ND ND 6/6 6/6 3.16

MYn IN AU _l_ T i up MMIN IVI 1I Knou IN VJ 1I 7n/ u 1 fi9 Middle 23 b b b b b b

Bottom 22 5470 49900 185 14.0 ND 400 3.11

INAI

i +i T Top O I I I ou a a 1 nn \ A > \

-i >fi fi 1O.0 MnINU Mn rwfi U/O n/fi U/O n fio + Middle 23 4490 52700 200 13.9 ND ND 6/6 6/6 2.82

4-1 Rnttnm 20 1820 31600 50 16 6 ND 1

1

0/6 0/6 0 97

F1 + + Top NM 390 2200 8 20.5 24 Trace 0/6 0/6 0.15 + Middle NM 2260 9200 23 19.0 44 ND 0/6 0/6 0.66 + Bottom NM 2500 8350 22 19.6 31 ND 0/6 0/6 0.64

FXO + + Top 23 1610 13100 11 18.8 60 17 0.51 Middle 23 2770 17100 16 18.1 22 4 0.78

Bottom 22 1530 14700 18 18.6 18 15 0.54

FX1 + + + Top 23 1750 16200 11 18.3 27 ND 0/6 0/6 0.56 + Middle 23 2530 21000 18 17.2 18 2 0/6 0/6 0.82 + Bottom 23 1060 12600 15 19.0 4 20 0/6 0/6 0.41 FX1a + + + Top 23 6000 27800 30 16.7 43 ND 6/6 6/6 1.65 + Middle 23 4750 21600 24 17.0 46 ND 5/6 5/6 1.29 + Bottom 21 2400 16800 12 18.1 54 ND 0/6 0/6 0.70

aAverage concentration over 30-minute exposure.

bAnimal exposure chamber leaked. ND Not detected. NM Not measured. N-Gas prediction based on equation:

m[CO] [HCN] 21 -[Q2] [HBr] [HCI]

[C02]-b +

160 +

21 -5.4 +3000 +

3700

where m = slope of LC50 line of CO in the presence of C02 and b = the y intercept of this line. Values used for m (-18.4 or 22.7 when C02 is below or above 5%, respectively) and b (122,000 or -39,000 when C02 is below or above 5°/o, respectively) were based on data obtained after 1 1986. 160 ppm,

5.4%, 3000 ppm and 3700 ppm are the 30-minute LC50 values of HCN, 02l HBr, and HCI, respectively.

table 18 Comparison of Peak Times and Concentration Areas for CO, HCI, HBr and HCN

in Large-Scale Tests (Burn Room).

CO HCI HBr HCN

Peak3 Peak3 Peak3 Peak3

Test Time Area Time Area Time Area Time Area

Number (min) (ppnvmin) (min) (ppnrmin) (min) (ppm-min) (min) (ppm-min)

N1 2.8 146980 1.5 3700 1.5 2670

NX0 2.5 152220 3 5960 3 2920

NX1 2.7 114800 7 8930 3 2650

F1 4.5 74870 12.5 860 2.5 4160 2.5 800

FXO 3.3 118520 35 7230 4 4220 14 1170

FX1 2.8 109820 9 5820 9 4290 7.5 1200

FX1a 3.8 112200 26 14880 4 5710 4 2100

'Measured from time of ignition

59
table 19 Specimen Mass Consumed in Large-Scale Tests.

Mass loss (kg)

Test TV Bus. mach. Chair Cables Ckt. Bd. Total Avg.

No. (H/G) (F/A) (T/S) (OIK) (C/L) (kg) (kg)

N1 3.6 3.2 5.2 4.6 13.4 30.0)

NXO 3.6 3.2 5.2 4.6 13.4 30.0 > 30.0

NX1 3.6 3.2 5.2 4.6 13.4 30.0 j

F1 2.1 0 3.9a 0 0 6.0 FXO 2.1 0 9.5a 0 0 11.6)

FX1 2.1 0 9.5a 0 0 11.6

| 12.0 FX1a 2.1 0 10.8a 0 0 12.9)

"Estimated from observations of video at 1800 s for F1 and 2100 s for remaining tests

table 20 Comparison Between Yields of Toxic Species in the Different Devices.

CO C02 HCN HBr HCI

(kg/kg) (kg/kg) (kg/kg) (kg/kg) (kg/kg)

NFR Cone Furn. Tox. Cone Furn. Tox.d Cone Furn. Tox. Cone Furn. Tox. Cone Furn. Tox. Specimen /FR Cal. Cal. Test. Cal. Cal. Test. Cal. Cal. Test. Cal. Cal. Test. Cal. Cal. Test.

TV Cabinet H NFR 0.015 0.12 0.084 2.28 1.39 2.09

TV Cabinet G FR 0.109 0.37 0.18 0.67 0.74 0.78 0.069 0.082 0.017 -

Bus. Machine F NFR 0.037 0.13 0.17 2.21 1.61 1.98

Bus. Machine A FR 0.055 0.29 0.30 1.60 1.45 1.53

Chair T NFR 0.020 0.01 1.62 1.89 - 0.002 0.001 Chair S FR 0.051 a 0.964 a 0.005 - - 0.023

Chair T

b NFR 0.016 0.025 1.71 — 2.05 0.002 - 0.0007

Chair S

b FR 0.055 0.15 0.81 — 1.19 0.0023 - 0.0032 — 0.022

Cable D NFR 0.041 0.12 1.77 1.61 — 0.112 0.121 Cable K FR 0.060 0.10 1.34 1.04 — 0.131 0.133

Cable D

c NFR 0.029 0.0506 2.19 — 2.38 - ND

Cable K

c FR 0.135 0.13 1.00 - 1.26 - 0.093

Circuit Bd. C NFR 0.014 0.10 0.075" 2.07 1.71 2.13

Circuit Bd. L FR 0.103 0.10 0.15 0.87 1.36 1.24 0.022 — 0.0043

"Could not be determined reliably. bFoam only, no cover fabric. °Wire insulation only. determined only from those tests where animals were not used. "Excludes data from the highest mass loading tested, since presumed unrepresentative.

—Not run ND Not detected

60
table 21 Fraction of Total Toxicity Accounted for by

CO (NBS Combustion Toxicity Test).

Sample FR CO toxicity/total toxicity

TV Cabinet H NFR 0.42

TV Cabinet G FR 0.75

Bus. Machine F NFR 0.53

Bus. Machine A FR 0.66

Chair T (foam) NFR 0.17

Chair S (foam) FR 0.45

Cable D (wire ins.) NFR 0.35

Cable K (wire ins.) FR 0.62

Circuit Bd. C NFR 0.44

Circuit Bd. L FR 0.68

All data represent averages of all replicates conducted in bench scale.

table 22 Fraction of Total Toxicity Accounted for by CO

(Large-Scale).

Test Animal chamber CO toxicity/total toxicity

N1 top 0.27

middle 0.33

bottom 0.34

avg. = 0.31 NXO top 0.38

middle N.A. bottom 0.27

avg. = 0.33

NX1 top 0.28

middle 0.24

bottom 0.28

avg. = 0.27

F1 top 0.39

middle 0.52

bottom 0.59

avg. = 0.50

FXO top 0.48

middle 0.54

bottom 0.43

avg. = 0.48

FX1 top 0.47

middle 0.47

bottom 0.39

avg. = 0.44

FX1a top 0.55

middle 0.56

bottom 0.52

avg. - 0.54

61
table 23 Times to Reach Untenable Conditions

in Large-Scale Tests.

Burn room Target room

Test Flashover3 CO FED CO FED

Number (s) (s) (s)

N1 110 164 200

NXO 112 167 215

NX1 116 168 226

F1 oo (185)

c oo (0.41 )d oo (0.33)

d

FXO oo (273)c 1939 oo (0.40)

d

FX1 oo (285)

c 2288 oo (0.29)

d FX1a oo (334)

c 1140 1013

aTime when temperature reached 600°C

bAuxiliary burner output exceeds this flux °Maximum burn room temperature (°C)

dMaximum CO FED attained FED Fractional Effective Exposure-dose

table 24 Comparison of Total Heat Release from

Large-Scale Fires with Furniture Calorimeter and

Cone Calorimeter Calculated Values.

Total Heat Release (MJ)

Large-Scale3 Test Number Individual Average Furn. Cone

N1 639)

NXO 479 > 542 730 752

NX1 507 j

F1 69 —b 94°

FXO 141' FX1 116 121 —b 199°

FX1a 105,

Corrected for auxiliary burner (252 MJ) and igniting torch (10 MJ)

bTV cabinet and chair only two items involved in fire; since Ahc for chair could not be determined from Furniture Calorimeter tests, the

result is indeterminate.

cComputed from TV cabinet and portion of chair consumed at 1800 s for F1 and 21 00 s for FXO, FX1 , and FX1 a.

table 25 Comparison of Smoke from Large-Scale Fires

with Furniture Calorimeter and Cone Calorimeter

Calculated Values.

Large-scale

Test

Smoke

prod.

(m2

) Avg.

N1 10540

NXO 8795 9900

NX1 10360,

F1 7148

FXO 12630'

FX1 12800 - 12400

FX1a 11890,

Smoke

yield

(m2/kg) Avg.

Furn. Cone

Cal. Cal. Smoke Smoke

yield yield

(mz/kg) (m2/kg)

330

1038

486

1097

638

780

970

725

62
table 26 Comparison of Average CO from Large-Scale Fires with Furniture Calorimeter, Cone Calorimeter, and

Toxicity Test Calculated Values.

Large-scale

Furn. Cal. Cone Cal. Tox. Test CO CO CO CO CO

Test prod. yield yield yield yield

Number (kg) Avg. (kg/kg) Avg. (kg/kg) (kg/kg) (kg/kg)

N1 6.6 0.22

'

NXO 5.5 5.5 0.18 > 0.18 0.09a 0.02 0.074

NX1 4.3 , 0.14 , F1 1.3 0.22 b 0.07 0.046

FXO 2.6 0.23

'

FX1 2.7 2.8 0.23 0.23 b 0.06 0.155

FX1a 3.0 , 0.23 ,

aBased on high values from Furniture Calorimeter which cannot be explained.

bTV cabinet and chair only two items involved in fire; since CO for chair could not be determined from Furniture Calorimeter tests, the result is indeterminate.

table 27 Total Toxicity Results in Large-Scale Tests.

avg. Test CO prod. total toxicity tot. tox. No. (kg) CO toxicity/total toxicity (CO-equiv. kg) (CO-equiv. kg)

N1 6.6 0.31 21

'

NXO 5.5 0.33 17 18

NX1 4.3 0.27 16,

F1 1.3 0.50 2.6 FXO 2.6 0.48 5.5' FX1 2.7 0.44 6.1 5.7 FX1a 3.0 0.54 5.6,

63
Sampling line from burn room

45 mm Teflon filters

Return line to burn room

Three way

valve

/

To

atmosphere

Cold trap

Teflon valves

I

i Filter Mass flow

controller

Pump

Figure 44. Impinger gas sampling in the large-scale burn room.

Rotameter (10 SCFHK

25 ml_ impingers

Top box

On/off valve

Middle

box

Bottom

box

25 mm

Teflon filter

CO

Rotameter

(96 mL/min)

MXJ=

1=00

Pump

To

atmosphere

Figure 45. Impinger gas sampling in the large-scale animal chamber.

64
NFR (Nl)

FR (Fl)

180 360 540 — 50 kW burner on720 900 10S0

TIME (S)

1260 1440 1620 1800

Figure 46. Heat release rates in the large-scale room/corridor/room

tests without the auxiliary burner.

180 360 540

50 kW burner on

720 900 1080 1260 1440 1620 1800

TIME (S)

120 kW burner on

NFR

FR

Figure 47. Heat release rates in the large-scale room/corridor/room

tests with the auxiliary burner.

65
20.0

18.0 -

in

too

u

o

<

a:

V)<

NFR (Nl) FR (Fl)

Figure 48. Mass flow rates of CO in the large-scale room/corridor/room tests without the auxiliary burner.

NFR (NXO)

NFR (NXi)

FR (FXO)

FR (FX1)

FR (FX la)

180 360 540 720 900 1080 1260 1440 1620 1800

TIME (S)

Figure 49. Mass flow rate of CO in the large-scale room/corridor/room tests with the auxiliary burner.

66
en

en

CMo

u

u.o

<

o

Ucn<

200

180 -

160 -

140 -

120 -

100 -

NFR (Nl)

FR (Fl)

180 360 540 720 900 1080

TIME (S)

1260 1440 1620 1800

Figure 50. Mass flow rate of C02 in the large-scale room/corridor/room tests without the auxiliary burner.

67
50.0

0.0

180 360 540 720 900 1080 1260 1440 1620 1800

TIME (s)

Figure 52. Smoke flow rates in the large-scale room/corridor/room

tests without the auxiliary burner.

50.0

45.0

40.0

s 35.0

cr j»x

30.0

o

_j

u.< 25.0 -

ID

(E<

z 20.0 h

oM

\ 15.0

M

t-2 10.0

5.0 H

0.0

— FX0 — FX1 — FXla — NX0 - NX1

180 360 540 720 900 1080

TIME (s)

1260 1440 1620 1800

Figure 53. Smoke flow rates in the large-scale room/corridor/room

tests with the auxiliary burner.

68
Assessment of Hazard

THE analysis of the fire hazard can be considered

two ways. Within the room of fire origin (or

within a nearby room), the time available from the

start of the fire until the time that untenable conditions

are reached is the crucial issue. On the other hand, if the fire is occurring in a large building, where significant distribution of the products of combustion is likely to occur via flows through ventilating systems,

stairwells, etc., then the exact time of incapacitation

cannot be derived for a far-removed occupant except

by doing detailed flow calculations. In such a case, however, it is possible to postulate that the hazard will

be proportional to the total amount of the products of

combustion (heat, smoke, toxic gases) that is released

from the fire. For completeness, both analyses will be

made.

6.1 TIMES TO UNTENABILITY

6.1.1 FLASHOVER

The ultimate event defining when a room becomes

totally untenable for the occupants is the occurrence

of flashover. Flashover is essentially the point at which the room becomes filled with flames. Quantitatively, it can be defined in various ways. For the purpose of evaluating the present large-scale results, it will be taken as the time when 600 °C is reached in the

upper gas layer of the room. The temperature values

will refer to two 0.05 mm thermocouples located near thermocouple tree 1 and 0.10 m down from the ceiling in the burn room. These values are listed in Table

23 for the burn room (no flashover events occurred in

the target room in any of the tests). The difference between the performance of the NFR and the FR series

is clear— in the NFR tests flashover occurred at just

under two minutes, at 113 s, on the average. For the

FR tests, meanwhile, flashover never occurred. For

those FR tests, the highest temperature reached was

334 °C, which is substantially less than the 600°C for

flashover.

6.1.2 HEAT FLUX

If the heat flux is excessive during a room fire, occupants may be receiving such painful heating that

viable escape options are not open. A heat flux value

of 2.5 kW/m2 is normally used as the criterion, determining when untenability due to excessive heat flux

will occur [5] . For those tests where the 120 kW auxiliary burner was used, the criterion value was ex- ceeded from the burner heating alone. Thus, those

tests could not be evaluated under this criterion. For

the remaining two tests, for the NFR products (test

Nl), the heat flux limit was exceeded in 41 s. For the

corresponding FR test (test Fl), the limit was exceeded

at 73 s, which is a significant improvement. These

results should not be used as the sole comparison of

the relative hazard, however, since the test without the

auxiliary burner does not represent a suitably high

challenge to the FR products.

6.1.3 FRACTIONAL EFFECTIVE EXPOSURE-DOSE

Another variable which can have a strong effect on

tenability is the toxicity of the combustion gases.

Since the gas concentrations in the large-scale tests (as

opposed to the NBS Combustion Toxicity Test) are not

constant over time, the time factor has to be explicitly

accounted for. This is most appropriately expressed as a "fractional effective exposure-dose" (FED). When

all the toxic gas components are being determined at each time step, it is possible to use simple summation

expressions to evaluate the FED at each time step [5]

.

69
7© ASSESSMENT OF HAZARD

For the present test series, the measurement of certain

gases (HCN, HC1, HBr) could not be done on a timeresolved basis; those gas data are available only as

over-all values for the entire test period. Thus, an

analysis approach was developed which is based on

the [CO toxicity/total toxicity] fractions computed

above. By this approach, if [CO toxicity/total toxicity]

is equal to, for example, 0.3, then the FED contribution for CO alone is summed at the appropriate location-burn room or target room- until FED = 0.3 is reached. At that instant of time, toxicologically

untenable conditions are presumed to occur. The CO

contribution to the FED was computed according to the method given in [5]:

J] (CO, - 1700)At, =

80,000

(6)

Using the CO toxicity ratios given in Table 22, toxic

hazard data based on the FED of CO are also presented in Table 23.

Excluding the results from test Fl, the results show

that for the NFR tests the critical CO FED was

reached in an average of 166 s in the burn room and

214 s in the target room. By contrast, the FR tests showed that it took an average of 1789 s to reach the

untenable value in the burn room. In the target room,

the untenable value was never reached, except for test FXla, where it was reached in 1013 s. Thus, the escape

time from the burn room, evaluated on a toxicity

basis, was increased by over 10-fold for the FR configuration, as compared to the NFR control.

6.1.4 SMOKE

In some large-scale fire testing a third criterion,

time to reach a prescribed vision obscuration due to smoke, is included. Since in the present test series no

instrumentation was included in the burn room for

measuring smoke, therefore, this criterion is not applied. Note, however, that smoke production data

(below) are available and are important in evaluating

the product performance.

6.1.5 OVERALL UNTENABILITY

As stated above, the data from the heat flux meter

should not be used in rating the actual performance.

This leaves two main criteria—flashover and the CO

FED. The earlier of the two governs the amount of es- cape time available for occupants. Thus, for the NFR

tests, this is the 113 s until the reaching of flashover in

the burn room. For the FR tests, the time of untenability occurs at 1789 s, when the critical CO FED is first reached. Thus, the occupants of the burn room would

have more than 15 -fold the escape time available for

the FR case than for the NFR.

The comparative results in the target room were

very similar (Table 23). However, since no flashover was achieved there for any of the tests, and for most

FR tests the CO FED critical value was never reached,

a quantitative evaluation is not made.

6.2 AMOUNTS OF COMBUSTION PRODUCTS

6.2.1 MASS CONSUMED

One beneficial effect of a fire retardant system is typically to reduce the amount of specimen mass burned.

Table 19 presents the data on specimen mass lost during the large-scale tests. In the case of the NFR tests,

it was assumed that all consumable weight loss oc- curred during the 30 or 35 minute test. Thus, these

specimen masses refer to the mass loss as recorded for

each item tested in the Furniture Calorimeter (Table

7). For the FR tests the only two items involved in the

fire were the television cabinet and the chair. The cabinet was visually observed to be consumed during the

30 or 35 minute tests; thus, it was taken to be 100%

consumed in computations. The amount of chair con- sumed after 30 or 35 minutes was estimated by observing the video tapes of the fire tests and these are the mass loss values recorded in Table 19. Certain

large-scale results can be averaged for this comparison. The presence or absence of animals certainly

does not affect specimen combustion. For the NFR

case, it can be concluded that the presence or absence

of the auxiliary burner had negligible effect; thus, the

N and the NX tests can be averaged together also. Excluding test Fl, then, the average mass lost for the FR

tests was 12 kg, compared to 30 kg for the NFR case. This more than two-fold improvement is significant.

6.2.2 HEAT RELEASED

While the Cone Calorimeter, Furniture Calorimeter, and bench-scale toxicity protocol tests help in

identifying the behavior of materials, the final evaluation has to rest with the large-scale result. One simple

comparison that can readily be made is the total heat

release measured from the large scale tests. Table 24

presents these data. The total heat release values for

the individual large-scale tests were taken from the

computer output at 100 s after the completion of the 30

or 35 minute tests. The tests where NFR materials were used showed an average of 542 MJ released,
Amounts of Combustion Products 71

while the corresponding FR tests showed only 121 MJ.

However, as can be seen from Figure 42, the fires have an extended smolder period after active burning is over. The rates of heat release occurring after the peak

burning is passed were small, on the order of 100 kW.

Since it can be assumed that there is an uncertainty of

approximately ± 50 kW associated with the measurement, it can readily be seen that when the heat release

rate curve is integrated, a substantial error can occur

if a significant amount of burning occurred during the

smoldering period. Thus, it is appropriate to also consider the data from the Furniture Calorimeter and the

Cone Calorimeter in attempting to arrive at the best

estimate of the actual heat released. The values re- ported in Table 24 have been derived by using the

specimen mass losses recorded in Table 19 and the

values of Ahc given in Table 8. For the NFR products,

the Furniture Calorimeter and the Cone Calorimeter

data agree very closely, indicating approximately 750

MJ. For the FR products, the heat of combustion for

one of the main fire-involved items, the chair, could

not be determined in the Furniture Calorimeter, due to the lack of flame spread in that test. Since the data for

the two devices agree so closely for the NFR case, however, it is appropriate to consider that the value of

200 MJ derived from Cone Calorimeter measure- ments for the FR case is the correct one. The "true" heats released are, then, taken as 750 MJ

for the NFR case and 200 MJ for the FR case, with an improvement of 3.5 to 4-fold over the NFR case. Using the data on the specimen mass burned above,

effective heats of combustion can also be computed for

the large-scale tests. These are:

25.0 MJ/kg for the NFR case

16.7 MJ/kg for the FR case.

Thus, it is seen that the improvement in the heat

released for the FR case is a combined effect, due in

part to the decreased specimen mass consumed and, in

part, due to the lowered heats of combustion.

6.2.3 PRODUCTION OF SMOKE

Table 25 gives the total production of smoke,

measured for the duration of the entire test. This was

determined by integrating the values recorded by the

smoke photometer located in the exhaust collection

system. The NFR tests showed an average of

9900 ± 1000 m2

, while the FR tests showed

12400 ± 500 m2. These are not statistically significantly different values at 2a.

Table 25 also lists the yields (per-mass-burned

values) of smoke in the large-scale tests, and compares

the yields that would have been predicted on the basis

of Furniture Calorimeter and Cone Calorimeter data.

Both these latter tests over-predict the yield for the

NFR tests and under-predict it for the FR ones. From the Furniture Calorimeter data in Table 8, it was concluded that the smoke yields were very similar

for NFR as for FR products, with the sole exception of

the polystyrene TV cabinets. The large-scale findings,

however, indicate a similar amount of smoke emitted, even though the amount of product burned in the FR

case was only about 1/3 of that for the NFR case. Part

of the explanation for this lies in the significant role of

the polystyrene TV cabinets. The TV cabinets, both

NFR and FR, are the smokiest product in the test

series, and are about 10 times as smoky as the chairs.

For the FR tests, even though the consumed mass

from the TV cabinet amounts to only 18% of the total,

according to the Furniture Calorimeter data (Table 8),

the cabinet contributes

2800 x 2.1(2800 x 2.1 + 180 x 9.9) = 77%

of the total smoke production. Thus, since the FR TV

cabinet is smokier than the NFR one, it is unsurprising that the total smoke production is not diminished

for the case of the FR tests.

6.2.4 PRODUCTION OF CO

Table 26 gives data on the production of CO. The

total yield of CO (kg) was determined from the gas

analysis measurements made in the exhaust collection

system. Averaging the tests in groups, as before, the

average large-scale production of CO is, then, equal to 5.45 kg for the NFR case and 2.77 kg for the FR case. The hazard associated with CO production, therefore,

is decreased by a factor of 2 for the FR case. Also listed in Table 26 are the yields, computed on

a basis of kg CO/kg fuel mass lost. There is no significant difference between the 0.18 kg/kg for the NFR

case, versus 0.23 kg/kg for the FR tests. Comparing

now these large-scale results to the data from the Furniture Calorimeter and the Cone Calorimeter, it can be seen that the predictability is generally poor. The

CO yield in the Furniture Calorimeter, as discussed

above, is substantially higher than in the Cone

Calorimeter. In turn, the CO yield in the actual largescale fire is twice again what was predicted from the

Furniture Calorimeter data.

6.2.5 TOTAL PRODUCTION OF TOXIC GAS SPECIES

Measuring capability for HCN, HC1, and HBr was

not available in the exhaust collection system. It is still possible to draw conclusions on the total toxic effluent

which was collected by making use of supplementary
72 ASSESSMENT OF HAZARD

bench-scale data. This evaluation can be accomplished in the following way. In the section above, the

quantities of CO produced were itemized. To arrive at an assessment of the total toxicity, these values must

be divided by a factor which represents [CO toxicity] /[total toxicity]. This is done very similarly as was

done above in determining the time to reach the criti- cal FED. Table 27 presents these results. These indicate an average value of 17.9 for the NFR products,

compared to 5.7 for the FR ones. Therefore, the contribution to toxic hazard from the FR products is decreased 3-fold, compared to the NFR ones.
1

Summary

7.1 PROPERTIES OF INDIVIDUAL

PRODUCTS TESTED

7.1.1 CONE CALORIMETER: IGNITABILITY

IGNITABILITY measurements in the Cone Calorimeter showed the following. None of the specimens,

NFR or FR, was especially susceptible to ignitability,

which is taken as showing ignition at an irradiance of

10 kW/m2 or less. At an irradiance of 30 kW/m2

, specimen S showed an ignition time which was about

double that of the NFR control, while specimen L

showed an improvement of 50%. For the remaining

specimens, the FR agent made essentially no

difference. At the high irradiance of 100 kW/m2

, the

FR agent did not change ignitability significantly for

any of the specimens.

7.1.2 CONE CALORIMETER: PEAK RATE OF

HEAT RELEASE

In almost all cases, the FR product showed a 2- to 3-fold improvement over the NFR one. The one ex- ception was the electrical cable, when tested at 30

kW/m2

, where no difference was seen.

7.1.3 CONE CALORIMETER: SMOKE YIELD

Smoke yield, per-kg-of-specimen-mass-loss, was

generally the same for the FR specimens as for the

NFR ones. The one exception was the polystyrene TV

cabinets, where the FR specimen showed about twice

the smoke yield as did the NFR one. The hazard

assessment, however, is not just based on this yield

data, since it comes from total production values, not

simply on the value for the smoke yield. This requires

knowing what the actual mass loss rates will be for the

large-scale test article, and cannot be obtained from

Cone Calorimeter data alone, unless a predictive relationship has already been determined.

7.1.4 CONE CALORIMETER: CO YIELD

The yields of CO from the FR products were typically higher than from the NFR ones. This does not

necessarily translate into higher production of CO for

the FR cases, since the amount burned has to be also

considered to determine that. The amount of specimen burned in the large-scale cannot as yet, in most

cases, be predicted from bench-scale measurements.

Thus, it is more appropriate to consider the actual

product toxicity hazards in the context of the largescale findings.

Here, we just note, further, that for some NFR specimens the CO yields obtained in the Cone Calorimeter

are low, in the range of 0.01 to 0.05. By contrast, measurements in the large-scale tests (and in the Furniture

Calorimeter) suggest that values in the vicinity of 0.1 are to be expected.

7.1.5 FURNITURE CALORIMETER FINDINGS

In all cases, the FR product was notably betterbehaved in its rate of heat release characteristics, compared to the NFR one. In some cases (the TV cabinets,

the business machine housings, the Z-arrangement

cable arrays, and the circuit boards) the FR product

showed, very roughly, half the RHR of the un-retarded

one. In other cases (the chairs and the cable arrays in

the vertical arrangement) the FR product showed no

continued flame propagation at all, leading to RHR

values which are much less, but not strictly comparable to, those registered by the NFR product. The

yields of CO and smoke, on a per-kg-of-specimenburned bases, were not greatly different, except for the

TV cabinets (CO and smoke) and the business

machine housings (CO). In those cases, the production from the FR specimens was 2 to 3 times that from

the NFR ones. However, since the burning rate was

also reduced by 13 to 23, the net hazard associated

73
74 SUMMARY

with the CO or smoke production was not significantly

increased over the NFR case. Caution must be exercised in interpreting and using

Furniture Calorimeter data when a no-continuedflame-spread result is reported. In the Furniture

Calorimeter tests, neither the FR cables nor the FR

chair showed sustained spread. As a result, for each

the rate of heat release of the FR specimen was

several-fold lower than for the NFR one. In the largescale tests, however, the FR cables still showed no fire involvement, but the FR chair was consumed. The

difference is attributed to different ignition sources. In

the large-scale tests, a scenario was specified where

the igniting burner was supplemented by the auxiliary

burner. There was also more than one item in the

room and, thus, there were interactions among burning items. The general caution, then, is that the results

for the FR item should not be stated as being "x many

times better" than for the NFR one if the FR one showed low heat release due to failure to spread flame

over its entire surface.

7.1.6 SMALL-SCALE TOXICITY TESTS

A modified NBS Toxicity Test protocol was used,

whereby a full LCS0 determination was not made, but,

rather, animal death results were compared against gas

analysis predictions at a few specimen mass loadings.

In no case was extreme toxic potency, identified as LCS0 < 2 mg/1, observed. The biological results

could be predicted on the basis of chemical analysis

for CO, COz , low 02 , HCN, HC1, and HBr for all specimens except the FR polystyrene TV cabinet

(specimen G), the FR cable wire insulation (specimen

K), and the FR polyester circuit board (specimen L).

For these three materials, additional agents may be

needed to account for 20-40% of the observed toxicity. For the NFR chair (specimen T), this question

could not be answered due to the experimental

difficulties in quantifying very low toxicity foam specimens. NFR wire insulation (specimen D) may also

need additional gases to account for no more than

20% of the toxicity.

7.2 RESULTS FROM LARGE-SCALE EVALUATIONS

OF NFR- AND FR-FURNISHED ROOMS

7.2.1 IMPACT OF FR MATERIALS ON THE

SURVIVABILITY OF OCCUPANTS OF ROOM OF

FIRE ORIGIN

This is judged by the time that is available to the oc- cupants before the earlier of (1) room flashover, or (2)

untenability due to toxic gas production occurs. For

the NFR tests, the average available escape time was

113 s. By contrast, for the FR tests, the time of untenability did not occur until 1789 s. Thus, the occupants

of the burn room would have more than 15-fold the es- cape time available for the FR case than for the NFR.

7.2.2 AMOUNT OF MATERIAL CONSUMED IN FIRE

The FR tests showed less than half the amount of

specimen mass lost as was lost in the NFR tests. Since mass loss is necessary before any hazardous combustion products can be generated, it can be concluded

that there is an effective hazard control at the very

outset.

7.2.3 AMOUNT OF HEAT RELEASED FROM

THE FIRE

The FR tests indicated an amount of heat released

from the fire which was 3.5 to 4 times less than that

released by the NFR tests.

7.2.4 TOTAL PRODUCTION OF TOXIC GASES

The total quantities of toxic gases produced in the

room fire tests, expressed in "CO equivalents," were

reduced 3-fold by the use of the FR products, compared to the NFR ones.

7.2.5 PRODUCTION OF SMOKE

The production of smoke was not significantly

different between the room fire tests using NFR products and those with FR products. The smoke production in the FR tests was dominated by smoke from the

polystyrene TV cabinets. This is consistent with the

smaller-scale tests, which showed smoke yield improvements for all FR products except for the TV cabinet. For the remaining four product categories, the

production of smoke from the FR products was

substantially smaller than from the NFR ones.

7.2.6 EFFECT OF AUXILIARY BURNER

The presence or absence of the auxiliary burner

made no effect on any test results for NFR materials.

For the FR tests, by contrast, the burner was clearly

proven necessary to obtain non-trivial fire involvement. In the one FR test run without the auxiliary

burner, the test chair was only partly consumed and

the specimen mass loss was less than half that for tests where the auxiliary burner was used.

7.2.7 COMPARISON TO PREVIOUS STUDIES

The results of the present large-scale study contrast
Relations Between Measurements in Different Test Methods 75

sharply to some earlier studies on fire-retarded products [e.g., 2]. In that earlier study the FR products ex- amined had a minimum retardant level, consistent

with lowest possible cost and the need to pass only the

simple California Bulletin 117 test [26]. Thus, not

unexpectedly, the FR products in that study did not

show measurably improved behavior. When FR formulations were chosen, as was done in the present

study, to represent high-quality, rather than minimum

cost systems, an entirely different, much more

favorable result is seen.

7.3 RELATIONS BETWEEN MEASUREMENTS IN

DIFFERENT TEST METHODS

7.3.1 PREDICTING HEAT RELEASE RESULTS FROM

CONE CALORIMETER DATA

Can the Cone Calorimeter rate of heat release measurements of fire-retarded products indicate the level

of improvement which the FR additive can affect in

the large scale? In answering this question, for three of

the five products tested, the bench-scale Cone Calorimeter measurements were seen to reflect very well

the large-scale Furniture Calorimeter results. The FR

products' improvement in performance was correctly

predicted and to a roughly similar quantitative magnitude. In the remaining two cases, such was not the

case. These were the electrical cables and the

upholstered chairs.

The electrical cables presented a new issue in

bench-scale testing. In almost all studies of heat

release rate prior to this work, it had been found that

when bench-scale specimens were prepared as composite, through-the-thickness samples cut out of the

large-scale article, an adequate representation of the

burning characteristics was obtained. During the course of this work, one of the first instances has been

identified where bench-scale samples prepared in this

way were not indicative of large-scale behavior. The

electric cable samples, when tested as such composites, did not accurately reflect the contribution of the

fire retardants located in the inner layers. The reason

for this was seen to be that the gasified FR agents from

the inner layers have an effect quite far away from the

immediate area of combustion. They not only

diminish burning in the vicinity of the pyrolysis re- gion, but also prevent flame spread further up the

cable array. This problem deserves further study, in

order to derive suitable predictive capabilities.

The upholstered chair data from the Cone

Calorimeter did not agree with the measurements

taken in the Furniture Calorimeter. In the Furniture

Calorimeter, the FR specimen performed well enough

so that progressive flame spread did not occur, and

only very little of the specimen was burned. The

bench-scale data, while showing clearly the

superiority of the FR formulation, did not indicate the

possibility of such no-spread behavior. It is more important to note, however, that the data from the Cone

Calorimeter did agree with the actual large-scale test

results, where the upholstered chair did spread flame

and burn nearly to completion. It cannot be overemphasized that while there may be wrong fire tests, in

the sense of ones based on such faulty physics as to never be useful, there are not, in general, right fire

tests — there can only be tests which are suited to a

specific scenario, application, product category, etc.

7.3.2 SCALE EFFECT ON TOXIC AGENTS

PRODUCED

7.3.2.1 Fraction of Total Toxicity Accounted for by CO

A comparison was made between the fraction of

total toxicity accounted for by CO in the bench-scale

NBS combustion toxicity test and the fraction

measured in the large-scale room/corridor/room tests. For both NFR and FR materials, the large-scale

results fell in the range circumscribed by the benchscale data. This suggests that neither the differences in

scale nor in the type of exposures involved in these

two devices preferentially change the degree of toxicity produced by CO. The NBS combustion toxicity

test is, thus, a reasonable device with which to characterize the CO.

7.3.2.2 Yields of the Toxic Gases

If the yields are similar for all species of interest in

two different test devices, then it may be concluded

that, at least for hazard assessment purposes, the essential aspects of combustion chemistry are preserved. In the present test series, C02 and HC1 measurements showed very close agreement. Because of

few measurements and high scatter, no firm conclusions for HBr or HCN yields are made.

For CO, there was substantive disagreement, with

the NBS combustion toxicity apparatus and, especially, the Cone Calorimeter giving some values

which were substantially lower than those observed in

the Furniture Calorimeter.

The large-scale results showed that there was no

difference in CO yield between the NFR and the FR

cases. In other words, the CO production for NFR

versus FR was in the same 2:1 ratio as were the re- spective mass losses. The predictability of these CO

yields was generally poor. The CO yields in the Furniture Calorimeter were only half of what was noted in
76 SUMMARY

the large-scale tests. In turn, the CO yields in the

Cone Calorimeter were several-fold lower yet than

what was observed in the Furniture Calorimeter. This

lack of scaling did not especially depend on whether

the products were NFR or FR. The reasons for this

lack of agreement can be manifold, however, it can be

surmised that both flame residence time and turbulent

mixing scale or intensity are governing chemical factors which are inseparably associated with scale. In- deed, the CO data from the Furniture Calorimeter

showed little variation amongst the specimens, both

NFR and FR.

The CO yields in the NBS Combustion Toxicity

Test were lower than in the corresponding large-scale

tests, while the yields of the remaining species being

measured were generally much more similar across all

test methods. Thus, for the question of whether

unusual toxic species are present, since these benchscale results are biased in favor of the non-CO species,

they are expected to yield false positives but not false

negatives. Such a conservative bound to the true

results is acceptable for a screening test. For resolving

the question of extreme toxicity, it is necessary to consider the behavior in the large-scale tests. The approximately 0.2 yield seen in the large-scale results, in

fact, is near the upper limit to CO yields, as seen in

other studies [27] . Thus, it is clear that extreme toxicity in large scale could not result by the increase of

CO yields by a necessary order of magnitude or more.

Instead, if any products show extreme toxicity in large

scale, it has to be by the increased quantities of the

other species. The NBS Combustion Toxicity test, however, as demonstrated above, is biased in favor of

the non-CO species. Thus, also for indicating extreme

toxicity it can be presumed to be a method where false

positives, but not false negatives, can be expected, and

is, therefore, conservative.

For accurate fire modeling to be achievable, it will

be necessary to predict correctly the CO in large-scale

fires. The data gathered in the present study reinforce

the growing evidence that the production of CO in

large-scale fire tests (and, thus, presumably in real

fires) is only somewhat influenced by the chemical

properties of the substance being burned. The CO

production is much more influenced by the availability

of oxygen in the large scale fire. This, in turn, is affected by variables such as geometry, ventilation

configuration, turbulence, and mixing. If this view is correct, the usage of any less-than-room-sized tests for

making CO predictions has to be deferred until these

oxygen supply variables are sorted out. Thus, in the

near future, emphasis has to be placed on the development of predictive algorithms which take into account

fluid mechanics, gas phase reactions, multiple-item

interactions, and other full-scale phenomena.

7.3.3 PREDICTING SMOKE YIELD RESULTS FROM

CONE CALORIMETER DATA

In all cases, the ratio between the smoke yields for

the NFR and the FR product were similar in the Cone

Calorimeter and in the Furniture Calorimeter.

The relationship between the numerical values in

the Furniture Calorimeter, versus those in the Cone

Calorimeter was typically 1:2. The exception to this

diminished smoke production in the larger-scale test came from the polystyrene TV cabinets. For the

polystyrene specimens, both the NFR and the FR ver- sions showed a greater smoke yield in the Furniture

Calorimeter than in the Cone Calorimeter.

7.3.4 USE OF LESS-THAN-ROOM-SCALE TESTS TO

PREDICT ROOM FIRE BEHAVIOR

Prediction of room fire behavior from smaller-scale

test data is a relatively recent area of fire research. A

basic prediction would require that both the burning

rate (heat release rate or mass loss rate) and the relevant yields of products could be predicted. The yields

have already been discussed. Attempts to predict the

burning rates are a new, yet important, area of endeavor. There are, generally, a number of physical

phenomena which cannot be adequately represented

by the smaller-scale test itself, and must be accounted

for by special data analysis techniques or by empirical

correction factors. Nonetheless, since there is a huge

economic incentive to utilize small-scale test wherever

possible, further advances need to be made. The techniques to predict the rate of heat release will be highly

dependent on the type of commodity being considered. Of the products being evaluated by FRCA,

only for upholstered furniture has work already been

done on relationships to predict the large-scale rate of

heat release from Cone Calorimeter data. For design

purposes, the predictability for NFR items is probably

satisfactory, however, further work would still need to be done on FR items, to determine, e.g. , the threshold

value from the Cone Calorimeter below which continued flame spread is to not be expected. For the re- maining classes of commodities, pursuit of such predictive relationships is still work for the future.
(q)

Conclusion

The fire performance of fire-retarded and non-fireretarded versions of several product types have

been studied using state-of-the-art fire science. It has

been demonstrated for representative fire-retarded

products that significantly enhanced fire performance

can be obtained, in that:

• The average available escape time was more

than 15-fold greater for the FR products in the

room burn tests. • The amount of material consumed in tests of

the FR products was less than half the loss in

the NFR tests. • FR products, on the average, gave 1/4 the

heat release of NFR products.

• The total quantities of toxic gas, expressed as CO-equivalents, released by the FR products

was 1/3 of that for the NFR products.

• The production of smoke was not significantly

different in room fire tests between FR and

NFR products.

The study shows, then, that the proper selection of

fire retardants can improve fire and life safety.

The conclusions developed in this study are pertinent only to the materials actually examined. Such

improvements are not to be automatically expected

from all fire-retarded products. Instead, it will still be

necessary to test and evaluate proposed new systems

individually. The research program provides a methodology to do that. The new instruments and analyses used to predict

the performance of these materials show promise.

The main current limitation is the inability to predict

accurately the production of CO from less-than-roomsized tests. Specific research efforts will have to be

addressed to solve this issue. Also, long-term efforts are needed to develop specific methods for predicting

the detailed burning rate characteristics of different

classes of commodities.

77

Ion Chromatography Procedure

APPARATUS

A commercially available ion chromatograph (Waters

Model ILC-1 IonLiquid Chromatograph) equipped

with a Waters 430 Total Conductivity Detector and a Waters

460 Electrochemical Detector was used to analyze for Br,

CI", and CN". The electrochemical detector was used with an Ag working electrode and a saturated KC1 reference electrode. An anion column (ICPAK-A) preceded by an Anion

Guard-Pak Precolumn Module, both commercially avail- able from Waters, was used. Chromatograms were recorded on a Spectra-Physics Model SP 4270 Integrator.

REAGENTS

All chemicals used in this work were of reagent grade

quality. The water used was conditioned to 18.3 Mfi-cm

and passed through a 0.45 urn nominal porosity filter. The

eluent for the ion chromatograph was 5 mM KOH. Stock

solutions of Br", CI", and CN", nominally 1000 ppm, were

prepared by dissolving 0. 1489 g of KBr, 0.2100 g of KC1,

and 0.2502 g of KCN, respectively, in 100 mL of the eluent

described above. Calibration solutions of 1.0 to 5.0 ppm

for Br" and CI" and 0.01 to 0.03 ppm for CN" were pre- pared by serial dilution of the stock solutions with the

eluent.

CHROMATOGRAPHIC PROCEDURE

The eluent flow rate through the system was 1.0 to 1.2 ml/min. The sample loop had a volume of 100 fA. Unknowns were diluted 1:10 for Br" and CI" and 1:100 for CN" with eluent. (There were a few unknowns that required a 1 : 1000 or 1 :500 dilution for CN".) Samples and standards were loaded into the loop using a syringe and a 0.45 /tm

syringe filter. The sample loop was rinsed with ca. 1 ml of

the analyte solution before the sample was injected onto the

column. The procedure, as evolved and described above, was successful in minimizing any mutual interferences

among the three anions of interest.

79

Gas Chromatography Procedure

The analytical procedure for the HCN determination was based on a gas chromatographic (GC) technique

utilizing an alkali flame (or thermionic) detector. The

details of this technique have been published [20]

A commercially available gas Chromatograph (Hewlett

Packard 5880) was used. Briefly, the analysis was carried out on a 1.8 m x 0.32 cm OD (6 ft. x 1/8 in. OD) stainless steel column packed with Porapak Q, 80/100 mesh. Column temperature was maintained at 110 C, injection port at

200 C, and the detector at 300 C. Helium was used as the

carrier gas at 30 ml/min. Air at 120 ml/min. and hydrogen

at 3 ml/min. were used as the detector gases. The combustion products were injected with a gas-tight syringe. Quantitation was based on integrated peak areas. Calibration of the alkali flame detector was performed

with commercially supplied mixtures of HCN in nitrogen.

The concentration of HCN gas mixtures was verified by

titration with standard silver nitrate solution [25].

81

Log of Large-Scale Test Observations

Test F1

Time (s) Comment

60 side of couch flaming

120 top side aflame very heavy smoke

200 burner off

230 still flame above TV

283 flames almost gone

315 flames out 420 target room peak CO in bot. chamber, 3800

ppm burn room peak temp 220 °C

660 inside of chair flaming (next to TV)

1140 flames out 1800 test over; auxiliary burner off

Post-fire analysis:

T.V. cabinet— consumed

left cushion— consumed

back cushion— 1/2 consumed

seat cushion — 1/4 consumed

right cushion— no damage

Test FXO

Time (s) Comment

0 120 kW auxiliary burner on

300 50 kW burner on

325 cabinet burning

330 couch

390 1/3 TV cabinet gone

top left arm couch aflame

500 50 kW burner off 510 temp in burn room same as before

810 flames covering almost entire top of seat cushion

900 circuit board on left burning

960 right side of cushion aflame

1770 back cushion fell on seat 2010 top of right cushion arm aflame

2100 test over; auxiliary burner off 2700 data logger off

first 6 inches backside cables intact next 20 inches badly charred white, yellowish ash, copper

strands exposed

next 42 inches covering split on most of cables exposing in- sulation

business machine cabinets were warped and shrunken

1/4 " circuit board charred to depth of 1/16 to 1/8 " only in regions behind T.V. cabinets & chair "S"

Test FX1

Time (s) Comment

0 120 kW auxiliary burner on (AP = 0.84)

0 + flames on ceiling

300 50 kW ignition turned on

330 flame collapsing back of TV cab

360 back TV consumed, only 1/5 TV frame con- sumed

390 all back TV and 1/2 front TV gone

420 both almost gone, arm of chair aflame, heavy

dense smoke from corridor

500 50 kW off burner

540 melt from TV burning on floor

780 seat cushion aflame for about 6 in. from left arm. 900 lower 6 in. height of back cushion aflame and

18 in. of flames across seat cushion

960 flames reached across only to right arm

(which has not ignited) flames about 18 in.

tall on seat cushion also burning on top of

left arm of chair

1170 inside right arm aflame along entire height

1320 top of right arm burning vigorously

1410 fire penetration of right arm cushion only

near top

1729 back cushion fell on seat and burning vigorously

83
84 APPENDIX C

2100 auxiliary, burner turned off 2280 right cushion penetrated, cables may be in- volved

2400 impinger sampling completed

2520 test data over

Test N1

Time (s) Comment

nu

Till 1/"\X/ Ki i r'n Ar /~\ f% dv kw Durncr on

30 pnohinn L Uol 11L/11 iriQiHp 11 lo I invnlvpH 111 VUl v cu

120 flashnvpr liwollL/VCJi rfiOO°P» X UL/L/ V_- ) 170 pan Idll tnlAJ Hoypq UUAtS tnrnpH IU1 litLi onL/l A 200 hiirn^r UUlilCi nflF Ull M11UKC ClCdilllg Up, Cllall gUUCU, C11CUH UUalU

niirtimn UU1 Ullig Vint UUl intuit* llilaLl, ^qVi1*=*c LaUlCb gUHC nnnp

660 only business machine burning

840 only remnants of business machine left and

burning; circuit board intact 1020 only 2 flamelets left on business machine

1920 test over

Test FX1a

Time (s) Comment

o 1"20 iz~\j V\Af ivv v anauAiiiai viliarvy hnrnpr uuinwi onvjiv ju kw igniiion source on

JLD i v pencil allOIl Oil UOHOIII OLD COUCH IgllllCU

390 hpavv HC'dV V cmnlfp' Ml IL/lLC , ton IKJiJ 1CJ.L Ipft arm CLl 111 pnnph LvVJUVll flaminc* Hull 1

son •JVJ SO IrW KW hnrnpr UU1I1CI nflF Ull

OH-U insiQc cusnions oi criair ydii *+) diiarnc

mo hapV niQninn fpll on spat

2085 only flamelets left on right side of chair

2100 test over; aux. burner off; only remnants of

cushion left on seat and lower right side

3000 data logger off

Test NX0

Time (s) Comment

0 120 kW auxiliary burner on

300 50 kW ignition source on

315 TV ignited

320 couch ignited

360 smoke 1/2 way down doorway

dense smoke

390 seat involvement

405 flashover chair

420 room flashover (~600°C)

500 50 kW burner off 720 fire clears; cables consumed

840 only business machine burning

2100 test over

Test NX1

Time (s) Comment

u 120 kW auxiliary burner on

inn 50 kW burner on TV ignites; chair ignites

lie. JJJ top right arm of chair ignites

ion flames half way to top of chair

4ZU nasnover (ouu

/IOC 435 smoke obscured fire completely

JUU ignition burner off 697 fire clearing up; fire spread beyond chair

Tin pump malfunctioned (maybe corridor room)

780 just business machine burning; cables completely burned up

1080 just flamelets left from business machine; circuit board folded up, partially burned

2100 test over 2970 data logger off
References

1 Babrauskas, V., "Development of the Cone

Calorimeter-A Bench-Scale Heat Release Rate Apparatus Based on Oxygen Consumption" (NBSIR 82-2611).

[U.S.] Nat. Bur. Stand. (1982).

2 Babrauskas, V., J. R. Lawson, W. D. Walton and W. H.

Twilley, "Upholstered Furniture Heat Release Rates Measured with a Furniture Calorimeter" (NBSIR 82-

2604) Nat. Bur. Stand. (1982).

3 Babrauskas, V., B. C. Levin, and R. G. Gann, "A New

Approach to Fire Toxicity Data for Hazard Evaluation."

ASTM Standardization News. 14, 28-33 (1986).

4 Braun, E., B. C. Levin, M. Paabo, J. Gurman, T. Holt

and J. S. Steel, "Fire Toxicity Scaling" (NBSIR 87-3510).

[U.S.] Nat. Bur. Stand. (1987)

5 Bukowski, R. W., W. W. Jones, B. M. Levin, C. L. Forney, S. W. Stiefel, V. Babrauskas, E. Braun, and A. J. Fowell, Hazard I. Volume I: Fire Hazard Assessment

Method (NBSIR 87-3602). [U.S.] Nat Bur. Stand. (1987).

6 Levin, B. C, M. Paabo, M. L. Fultz, C. Bailey, W. Yin

and S. E. Harris, "An Acute Inhalation Toxicological Evaluation of Combustion Products from Fire Retarded and

Non-Fire Retarded Flexible Polyurethane Foam and

Polyester" (NBSIR 83-2791). [U.S.] Nat. Bur. Stand.

(1983).

7 Huggett, C, "Estimation of Rate of Heat Release by

Means of Oxygen Consumption Measurements," Fire and

Materials, 4, 61-65 (1980).

8 Babrauskas, V., and G. Mulholland, "Smoke and Soot

Data Determinations in the Cone Calorimeter," pp. 83-104 in Mathematical Modeling of Fires (ASTM STP

983), American Society for Testing and Materials, Philadelphia (1987)

9 Babrauskas, V., "The Cone Calorimeter-A Versatile Bench-Scale Tool for the Evaluation of Fire Properties,"

pp. 78-87 in New Technology to Reduce Fire Losses &

Costs, S.J. Grayson and DA. Smith, eds., Elsevier Applied Science Publishers, London (1986).

10 Proposed Test Method for Heat and Visible Smoke

Release Rates for Materials and Products using an Oxygen

Consumption Calorimeter (P 190). Annual Book ofASTM

Standards, Vol. 04.07, American Society for Testing and

Materials (1986).

11 Levin, B. C, M. Paabo, M. L. Fultz and C. S. Bailey,

"Generation of Hydrogen Cyanide from Flexible

Polyurethane Foam Decomposed under Different Combustion Conditions," Fire and Materials 9, 125-134

(1985).

12 Babrauskas, V. , "Will the Second Item Ignite?" Fire Safety

J. 4, 281-292 (1981/82).

13 Babrauskas, V, "Upholstered Furniture Room Fires

Measurements, Comparison with Furniture Calorimeter

Data, and Flashover Predictions," J. of Fire Sciences, 2

5-19 (1984).

14 Mulholland, G. M., V. Henzel Babrauskas, V, "The

Effect of Scale on Smoke Emission," paper to be presented

at Fire Safety Science, Second International Symposium

(1988).

15 Babrauskas, V, "Free Burning Fires," Fire Safety J., 11, 33-51 (1986).

16 Babrauskas, V. and W. D. Walton, "A Simplified Characterization for Upholstered Furniture Heat Release Rates," Fire Safety J., 11, 181-192 (1986).

17 Quintiere, J. G, paper presented at the ASTM E-5

Research Review, Bal Harbour, FL (December 1987).

18 Levin, B. C, M. Paabo, J. L. Gurman and S. E. Harris,

"Effects of Exposure to Single or Multiple Combinations

of the Predominant Toxic Gases and Low Oxygen At- mospheres Produced in Fires," Fund. Appl. Tox., 9, 236-250 (1987).

19 Levin, B. C, A. J. Fowell, M. M. Birky, M. Paabo, A.

Stolte and D. Malek, "Further Development of a Test Method for the Assessment of the Acute Inhalation Toxicity of Combustion Products (NBSIR 82-2532)," [U.S.] Nat. Bur. Stand. (1982).

20 Paabo, M., M. M. Birky and S. E. Womble, "Analysis of

Hydrogen Cyanide in Fire Environments," J. Comb. Tox,

,

6, 99-108 (1979). 21 Jones, W. W. , "Future Directions for Modeling the Spread

of Fire, Smoke, and Toxic Gases," Fire Safety: Science and

Engineering, ASTM STP 882, T. Z. Harmathy, Ed.,

American Society for Testing and Materials, Philadelphia, pp. 70-96 (1985).

22 Lee, B. T, "Quarter-Scale Modeling of Room Fire Tests of Interior Finish (NBSIR 81-2453)," [U.S.] Nat. Bur. Stand. (1982).

23 Steckler, K. D, J. G. Quintiere and W. J. Rinkinen, "Flow

85
86 References

Induced by Fire in a Compartment (NBSIR 82-2520)"

[U.S.] Nat. Bur. Stand. (1982).

24 Jones, W. W. , and R. D. Peacock, "Experimental Verifica- tion of a Model for Fire Growth and Smoke Transport,"

paper to be presented at the Second Annual Symposium

on Fire Safety Science, Tokyo, Japan (June 1988).

25 Kolthoff, I. M. and E. B. Sandell, Textbook of Quantitative Organic Analysis, 2nd Ed., p. 546. The MacMillan

Co., New York, (1953).

26 Flammability Information Package (Contains Technical

Bulletins 116, 117, 121, and 133). Bureau of Home Furnishings, Dept. of Consumer Affairs, State of California,

North Highlands (1985).

27 Mulholland, G. W., private communication (1988).
FORM NBS-1 I4A (REV. 11 -84)

U.S. DEPT. OF COMM.

BIBLIOGRAPHIC DATA

SHEET (See instructions)

1. PUBLICATION OR

REPORT NO.

NBS/SP-749

2. Performing Organ. Report No. 3. Publication Date

July 1988

4. TITLE AND SUBTITLE

FIRE HAZARD COMPARISON OF FIRE-RETARDED AND NON-FIRE-RETARDED PRODUCTS

5. author(S) Vytenis Babrauskas , Richard H. Harris, Jr., Richard G. Gann, Barbara C.

Levin, Billy T. Lee, Richard D. Peacock, Maya Paabo, William Twilley,

Margaret F. Yoklavich, Hclcnc M. Clark

6. PERFORMING ORG/AN I ZATION (If joint or other than NBS, see instructions)

NATIONAL BUREAU OF STANDARDS

U.S. DEPARTMENT OF COMMERCE

GAITHERSBURG, MD 20899

7. Contract/Grant No.

8. Type of Report & Period Covered

Final

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

Fire Retardant Chemicals Association

Lancaster, PA 17604

10. SUPPLEMENTARY notes

Library of Congress Catalog Card Number: 88-600560

[ J Document describes a computer program; SF-185, FlPS Software Summary, is attached.

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

bibliography or literature survey, mention it here)

A test program was conducted for the Fire Retardant Chemicals Association to

quantify the effects of fire retardant chemicals on total fire hazard. Five

different types of products, each made from a different type of plastic were

used. The products were made up in analogous fire -retardant (FR) and nonretarded variants (NFR) . Cone Calorimeter, Furniture Calorimeter, and NBS

combustion toxicity tests were run on the individual products. The ultimate

evaluation was made through the use of a large-scale burn room/corridor/target

room facility. The test results showed very substantial improvements for the

FR products in the areas of increased occupant escape time and decreased

production of heat and toxic gas species. The production of smoke was

unchanged with the FR products, compared to the NFR ones. It was specifically

demonstrated that the overall hazard was reduced, and that reduced burning

rates were not obtained at the expense of increasing the hazard due to

combustion toxicity. Most of the combustion product effects could be accounted

for by the normal gases monitored, and it was also shown that none of the

products, either FR or NFR, constituted hazards due to extreme toxic potency.

12. KEY WORDS (Six to twelve entries; alphabetical order; capitalize only proper names; and separate key words by semicolons)

Cone Calorimeter; fire gas toxicity; fire retardant chemicals; Furniture

Calorimeter; ion chromatography; plastics; rate of heat release; room fire

tests; smoke production.

13. AVAILABILITY

KH Unlimited

For Official Distribution. Do Not Release to NTIS

C£~~| Order From Superintendent of Documents, U.S. Government Printing Office, Washington, DC

20402.

Order From National Technical Information Service (NTIS), Springfield, VA 22161

14. NO. OF

PRINTED PAGES

92

15. Price

USCOMM DC 85-6004



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75 Years Stimulating America s Progress 1913-1988