Development of the Flooring

Radiant Panel Test as A

Standard Test Method

C. Howard Adams, Research Associate

The Society of the Plastics Industry

New York, New York

and

Sanford Davis

Center for Fire Research

National Engineering Laboratory

National Bureau of Standards

U.S. Department of Commerce

Washington, D.C. 20234

March 1980

Final Report

Sponsored in part by;

The Society of the Plastics Industry

355 Lexington Avenue

New York, New York 10017 —QC' , 100

.056

0.79-1954

1980

NBSIR 79-1954

DEVELOPMENT OF THE FLOORING

RADIANT PANEL TEST AS A

STANDARD TEST METHOD

C. Howard Adams, Research Associate

The Society of the Plastics Industry

New York, New York

and

Sanford Davis

NATIONAL BUREAU OF STANDARDS

LIBRARY JUN ^ 5 1980

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Center for Fire Research

National Engineering Laboratory

National Bureau of Standards

U S. Department of Commerce

Washington, D.C. 20234

March 1980

Final Report

Sponsored in part by;

The Society of the Plastics Industry

355 Lexington Avenue

New York, New York 10017

U S. DEPARTMENT OF COMMERCE, Philip M. Klutznick, Secretary

Luther H. Hodges. Jr., Deputy Secretary

Jordan J. Baruch, Assistant Secretary for Productivity. Technology, and Innovation

NATIONAL BUREAU OF STANDARDS, Ernest Ambler, Director
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TABLE OF CONTENTS

Page

LIST OF TABLES

LIST OF FIGURES

Abstract 1

1. INTRODUCTION 2

1.1 Problem Statement 2 1.2 Background 2 1.3 Approach to Standarization 4

2 . OBJECTIVE 4

3. THE TEST PROCEDURE 5

4. DEVELOPMENT OF THE TEST PROCEDURE 5

4.1 Selection of Test Conditions 5 4.2 Flooring System Concept 6

4 . 3 Tester Start Up 6 4.4 Flux Profile Determination 7 4.5 Preheat Study 8 4.6 Ignition Source Definition 8 4.7 Specimen Geometry Effect 9

5. APPARATUS DESIGN, ENGINEERING, AND DEVELOPMENT 10

5.1 Safety Precautions 10

5.2 Fuel Control and Monitoring 10

5.3 Radiant Panel 10

5.4 Radiant Energy Flux Profile Instrumentation 11

5.4.1 Requirements 11

5.4.2 Instrument Selection 11

5.4.3 Calibration 12

5.5 Chamber and Stack Thermocouples 13

5.6 Flaming Ignition Source - Pilot Burner 13

5.7 Specimen Mounting System 14

5.8 Chamber Details 14

6. NBS DATA ON FLOORING SYSTEMS 15

7. INTERLABORATORY PROGRAMS 15

7.1 Phase I NBS/MMFPA/CRI Interlaboratory Program 15

7.1.1 Sample Selection 16

7.1.2 Testing Phase 16

7.1.3 Statistical Analysis 17

7.2 Phase II NBS/MMFPA/CRI Interlaboratory Program 17

7.2.1 Sample Selection and Testing 17

7.2.2 Statistical Analysis 18

7.2.3 Optimum Number of Specimens 18

7.2.4 Contract Carpet Performance 19

7.3 Concluding Statement 19

8. CONCLUSIONS 19

9. ACKNOWLEDGEMENTS 19

iii
TABLE OF CONTENTS (continued)

Page

10. REFERENCES 20

APPENDIX A. REPORT OF CALIBRATION DETECTOR RESPONSIVITY OF THREE

THERMAL DETECTORS A-1

APPENDIX B. NBS CENTER FOR FIRE RESEARCH TOTAL RADIANT FLUX METER,

REFERENCE CONVERSION FACTOR B-1

IV
LIST OF TABLES

Page

Table 1. Position of the flux meter 22

Table 2. Effect of the acetylene-air pilot flame on the radiant

energy flux profile 23

Table 3. Effect of 2- and 5-minute preheat times on seven wool

carpet samples 24

Table 4. Effect of preheat and ignition flame contact time on typical carpets 25

Table 5. Effect of pad type and preheat on tufted acrylic carpet . 26

Table 6. Test data on wood and resilient flooring products .... 27

Table 7 . Specimen geometry study

Small specimen - standard specimen equivalency 28

Table 8. Test data on carpets from actual corridor fire cases ... 29

Table 9. Flux meter calibration log 30

Table 10. Total flux meter calibration, Enqineering A| >pl i cat ionn

Branch, Goddard Space Flight Center 31

Table 11. Effect of cushion pad types on critical radiant flux

for a nylon 6,6 carpet 32

Table 12. Data on Carpet and Rug Institute, Man-Made Fiber

Producers Association samples, no preheat 33

Table 13. Phase I NBS/MMFPA/CRI Interlaboratory Program data,

no preheat 34

Table 14. Phase II Part A NBS/MMFPA/CRI Interlaboratory Program

data, two-minute preheat 35

Table 15. Phase II Part A NBS/MMFPA/CRI Interlaboratory Program,

Effect of number of specimens on repeatability and

reproducibility 36

Table 16. Phase II Part B NBS/MMFPA/CRI Interlaboratory Program

data, two-minute preheat 37

V
LIST OF FIGURES

Page

Figure 1. The Flooring Radiant Panel Test 39

Figure 2. Blackbody temperature distribution on non-uniform radiant

panel 40

Figure 3. Critical radiant flux map 41

Figure 4. Distribution of contract carpet products by critical

flux ranges 42

vi
DEVELOPMENT OF THE FLOORING RADIANT PANEL

TEST AS A STANDARD TEST METHOD

C. Howard Adams* and Sanford Davis

Abstract

This report deals with the standardization phase

of the Flooring Radiant Panel Test. It describes work

done to develop the test as a standard for measuring

one of the major factors contributing to the potential

fire hazard of floor covering systems used in corridors

and exitways.

The investigation involved major inter 1 aboratory

test programs and focused on: 1) establishing realistic

test conditions; 2) defining and minimizing variability;

3) drafting a complete and concise test procedure; and

4) demonstrating the soundness of the method.

Required flux profile instrumentation calibration

procedures were developed and proven. "Critical radiant

flux" data obtained on representative floor covering

systems showed the rank ordering of important products

such as man-made and natural fiber carpets, vinyl asbestos

tile, and hardwood flooring. Acceptable repeatabilities

of about 20 percent (within-laboratory variability) and

reproducibility of about 35 percent (between-laboratory

variability) were demonstrated in two major NBS/MMFPA/CRI

interlaboratory carpet system test programs. Fourteen

laboratories participated in these full factorial statistically designed experiments with each laboratory testing

eighteen carpet materials.

Key words; Critical radiant flux; fire safety; flame

spread; flammability; floor coverings; flooring radiant

panel test; test method.

This work was conducted while Mr. Adams was a research associate at the

National Bureau of Standards for The Society of the Plastics Industry.

1
1. INTRODUCTION

1.1 Problem Statement

The first U.S. national standard for the surface flammability of carpets

and rugs was DOC FF 1-70 (the pill test) . This test provides a mandatory

limit on the propagation of flame on a carpet sample exposed to a small timed

burning tajalet and is intended to assure that the carpet will not be: 1) the

first item ignited by a small flame, spark or ember, nor 2) the sole mechanism

by which a fire propagates. In January 1970, well before the standard became

mandatory in April 1971, a serious fire spread along a corridor in a Marietta,

Ohio nursing home claiming 31 lives. This fire, and others in which the

corridor floor covering was a major contributor to fire spread, confirmed the

need for another type of test, one which would measure how carpets burn when

involved in a larger fire. The problem restated was to develop a test which

would measure the degree to which the floor covering system presents a fire

propagation link in a corridor and/or exitway given a fire in an adjoining

room, i.e., the tendency for a floor covering system to produce sustained

flame spread after ignition, in the presence of a radiant energy load. This

is a historical document and deals with the standardization phase of the

Flooring Radiant Panel Test.

Reduced to its basics, the floor covering system fire question must

deal with these two issues:

1. The ease of ignition in a " f irst-to-ignite" situation, i.e., under

zero incident radiant energy flux.

2. The degree to which the floor covering system presents a fire

propagation link in a corridor and/or exitway given a fire in an adjoining room, i.e., the tendency of a floor covering system to

produce sustained flame spread after ignition, when exposed to

external radiant heat.

The test method described in the "Standard for the Surface Flammability

of Carpets and Rugs", DOC FF 1-70 (the pill test), is felt to be an appropriate

and valid measure of ignition ease and potential flame propagation under zero incident radiant energy conditions. Floor coverings which meet the requirements of the pill test would be expected to provide adequate " f irst-to-ignite"

protection in all occupancies.

2
The Flooring Radiant Panel Test is designed to deal with one aspect of; the fire propagation assessment of floor covering systems in corridors and

exitways at a time prior to the corridor's involvement in the fire. The

potential fire exposure spans the range from low to high heat flux levels

from a room fire source and the test therefore imposes a moderately high

radiant energy load on the flooring system combined with a flaming ignition.

The test measures a single fire property which by itself does not relate

directly to fire hazard. The test does not measure smoke or toxic combustion \

products which may be of overriding importance and it also does not measure

fire propagation potential of carpeting mounted on walls and ceilings.

1.2 Background

The need for fire risk assessment had been anticipated and acted on by

the U.S. Public Health Service as early as 1965 when a directive was issued

regulating the use of carpets in hospitals receiving financial aid under the

Hill-Burton Act [1]^. The directive established a tentative flame spread

limit of 75 (by the ASTM E 84 Tunnel Test) for carpeting and other floor

covering materials used in patient occupied areas. The tentative qualification is supported by a 1967 critique of E 84 in which it was concluded

"... use of the test method for this purpose can be justified only on the

basis that a suitable fire test for floor covering does not exist" [2].

in 1969, the Department of Health, Education, and Welfare (HEW) undertook

the development of a "suitable" test by sponsoring work at Underwriters

Laboratories (UL) which culminated in the development of the UL 992 Chamber

Test [3]

.

This test generates an index but it has not been shown that the

test environment relates to the potential hazard of fire growth in a full-scale

corridor. The NBS Model Corridor [4]

,

essentially an extension of the UL work,

lead to the concept of critical radiant flux, the basis for ranking of floor

covering systems in the Flooring Radiant Panel Test.

The Flooring Radiant Panel Test had its beginnings in the laboratories

of the Armstrong Cork Company in 1966. This was followed by the test development phase which was completed by an Armstrong NBS Research Associate during

the 1972-73 period [5]. The standardization work was done during 1974-75 and

is the subject of this report.

Numbers in brackets refer to the literature references listed at the end

of this report.

3
While these small-scale tests were being developed, full-scale corridor

studies designed to gain a better understanding of the mechanism controlling

the spread of fire along a carpeted corridor were being carried out at NBS,

IITRI, and NRC (Canada). This work provided important insights of value to

the Flooring Radiant Panel Program, one of which is summarized in the following

quotation

:

"... In a floor covering application, material acceptance may be

based on a critical radiant flux level anticipated in a building

corridor due to a given room fire exposure. Although this concept

ignores many factors, it does focus on the significant factor which

contributes to flame over." [5]

1.3 Approach to Standardization

The approach to standardizing the Flooring Radiant Panel Test was the

straightforward one of building on the work of previous investigators. Among

the important steps taken to achieve the desired result were these:

1. SolectioM and standardization of test conditions which are relevant

to a (irc‘ .situation, i.o., spread of fliiiiie on a c’orridoi flooi

given a fire in an adjoining room.

2. Identifying and minimizing causes of variability.

3. Drafting a complete and concise test procedure.

4. Promoting major interlaboratory test programs designed to determine

the utility of the test.

5. Development of guidelines, background, and data in support of proposed criteria for potential use of the method as a regulatory tool.

2 . OBJECTIVE

The objective of this project was to develop the Flooring Radiant Panel

Test as a relevant, reproducible, standard method for measuring one important

fire hazard characteristic of floor covering systems in corridors and exitways.

4
3. THE TEST PROCEDURE

The original procedure describing the "Standard Method of Test for

Critical Radiant Flux of Floor Covering Systems Using a Radiant Heat Energy

Source" has been published in an earlier report [7]

.

The reader is referred

to ASTM E 648-78 for the current test procedure and apparatus details [8]

.

This latest version of the test procedure incorporates slight changes based

on comments and inputs from the many individuals who are currently operating

the test apparatus--approximately forty.

The basic elements of the test hardware are shown in figure 1. The

horizontally mounted 100-cm floor covering test specimen receives radiant

energy from an air-gas fueled radiant panel mounted above the specimen and

inclined at an angle of 30° to the horizontal. A pilot burner provides a source of open flame ignition of the specimen. The gas panel generates a flux

profile along the length of the specimen ranging from a maximum of 1.1 W/cm^

at the 10-cm location to 0.1 W/cm^ minimum at the 90-cm location.

As the first step in carrying out a test, the floor covering system

specimen is carefully mounted in the holding frame. With the chamber at

equilibrium conditions, the specimen is moved into the test position and the

chamber is closed. Following the 2-minute preheat of the specimen by the

radiant panel, the pilot burner flame is applied. The test continues until

the specimen flaming goes out (extinguishment) . The maximum distance burned

is converted to the corresponding radiant flux level from the calibrated flux

profile graph and the result is reported as a critical radiant flux, W/cm^

.

This value represents the minimum flux necessary to sustain flame propagation

on the flooring surface under the test conditions.

4. DEVELOPMENT OF THE TEST PROCEDURE

4.1 Selection of Test Conditions

Selection of test conditions was based on the 1972-73 flooring radiant

panel work of Hartzell and full-scale corridor investigations during the

period 1971-74 [9]. Hartzell studied four combinations of panel angle, panel

distance to specimen plane, and panel temperature. He concluded that a panel

angle of 30°, a panel to specimen distance of 14 cm, and a panel radiance

5
corresponding to that of a blackbody operating at a temperature of \'500‘’C

produced the best results. The radiant flux profile along the specimen,

ranging from "^^l W/cm^ to 'V'O.l W/cm^ , provided the differentiation needed,

i.e., spaced the critical flux values obtained on a common group of carpets

more broadly than the other three conditions. Further, this combination of

geometry and temperature gave a radiant energy flux distribution that more nearly approximated linearity than the others.

4.2 Flooring System Concept

The work of previous researchers in the floor covering field showed the

importance of system testing as opposed to single element testing. For

example, it was observed in the full-scale corridor studies, in the model

corridor program, and in the Flooring Radiant Panel Test development, that a carpet placed directly on a high density inorganic board substrate would

generally be more resistant to the spread of flame than the identical carpet

over a rubberized jute pad on the same inorganic board substrate. Other system

variables which may affect flame propagation are: choice of substrate, e.g.,

plywood or cement asbestos board, and method of attachment to the substrate,

e.g., edge clamped or adhesive bonded. The specimen mounting frame was designed to accommodate system assemblies up to 4.5 cm (1-3/4 in) in thickness.

The procedure presents system assembly and mounting guidelines.

4.3 Tester Start Up

The specifics of chamber start-up will be determined to a degree by the

type of safety devices installed on a particular unit. The description of

steps involved in putting the tester in operation must therefore be generalized. First, with the sliding specimen platform out of the chamber, the

fuel mixture flow settings are made and the gas/air mixture issuing from the

panel face is ignited. The bottom of the chamber is open during the equilibration which may require 1 hour. It will be helpful to read the panel

equivalent blackbody temperature about 30 minutes after ignition. If it has

reached the prescribed temperature, in accordance with the procedure, the

chamber is ready for use, i.e., testing or flux profile determination. The

procedure treats these steps in detail.

References to blackbody temperatures in this report are to radiant panel

operating conditions which yield a radiance at the panel surface equivalent

to that of a blackbody at the temperature referenced, as measured by the

radiation pyrometer.

6
4.4 Flux Profile Determination

The flux profile determination must be done with great care in view of

its importance as the base line for the critical radiant flux measurement.

Instrumentation and calibration issues are treated below in section 5.4. This

portion of the report covers the work done to define the operational parameters

that could impact on the character of the flux profile curve and the precision

of its determination. It is axiomatic that the measured flux profile should

reflect in high degree the actual radiant energy levels incident on the speciI men plane at or near the critical radiant flux point at the time of flameout

during an actual test. For this to be accomplished, the chamber with the

specimen plane closed with the dummy specimen in place must be at thermal

equilibrium. Consequently, studies were conducted to determine the rate at

which chamber stabilization occurred. The starting point was the bottom open

chamber radiant panel equilibrium condition. The bottom closed time to thermal

equilibrium investigation was started by mounting the dummy specimen in the

specimen frame and mounting the assembly on the specimen frame transport. It was then moved into the chamber and the lower door closed. Total radiant flux

readings at the 40-cm location on the specimen plane were taken after 5 minutes

and at 5-minute intervals thereafter until equilibrium conditions were established. Stack temperature measurements were made at the same times and the

data showed that thermal conditions were stabilized within the 30-minute

period called for in the procedure.

The flux profile determination was made with the dummy specimen in place

and the chamber at equilibrium as described above. The flux profile measurements begin with the 10-cm point. The flux meter is inserted in the opening

so that its detecting plane is 0.16-0.32 cm (1/16-1/8 in) above and parallel

to the plane of the dummy specimen to simulate the average projection of carpet

specimens above the plane of the dummy specimen. Its output is read after

30+5 seconds based on experimental evidence which showed flux meter reading

stabilization was achieved at 20 seconds. The effect of height of flux meter

detecting plane above the dummy specimen plane was studied and shown to be

insignificant from 0.96 cm (0.38 in) to 0.13 cm (0.05 in) which brackets the

above recoromendations (see table 1) . The 10-cm procedure was repeated for the

20-cm point and at 10-cm intervals thereafter, up to and including the 90-cm

location. The effect of the fdaming ignition source (pilot burner) at selected

distances along the specimen plane on the flux profile was investigated and

found to be beneath the level of detection (see table 2) . As indicated in the

procedure, the final step in the profile operation was to plot the radiant heat

energy flux data as a function of distance along the specimen plane on rectangular coordinate paper.

7
4 . 5 Preheat Study

The advantage of using a preheat period was demonstrated following analysis

of data scatter (poor repeatability) observed for a group of wool carpets.

Preheat time refers to the interval between moving the specimen into the

chamber test position (with the chamber then being closed) and the application

of the flaming ignition source to the specimen. The first column of table 3 lists the results with no preheat. The third column documents the improved

data repeatability obtained with the introduction of a 5-minute preheat step.

Another experiment, the effect of preheat and ignition flame contact time on

a representative group of carpets was studied (table 4) . The data confirmed

the need for a preheat with wool carpets but showed that the acrylic and polyester fiber carpets, in general, were affected only to a small degree, if at

all; also, the flame contact time was not a factor. Table 5 summarizes the

results of an experiment designed to evaluate the effect of preheat on a tufted

acrylic carpet as a function of four cushion pad types. The effect of preheat

is less pronounced than that resulting from the use of a pad; also, the type

of pad does not cause significant differences. The preheat effect on oaJc flooring and resilient flooring was investigated in a limited experiment

(table 6) . These data show that preheat times up to 5 minutes had no effect

on the critical radiant flux values obtained. The observation holds for the

resilient sheet flooring with a urethane wear surface. Of the three sheet

vinyl flooring products, one of the sample C specimens flashed during the 5-

minute preheat, presumably due to volatile plasticizer being ignited by the

pilot flame which during preheat is about 5 cm (2 in) above the specimen plane*.

This occurred following 4-minute exposure in the preheat cycle. The final

preheat time selected for the procedure was 2 minutes, an arbitrary choice

based on analysis of the data on wool carpets and consideration for the flashing

observed in the above resilient flooring product.

4.6 Ignition Source Definition

The flaming ignition source is described in section 5.6. In much of the

early wor)t at NBS, the acetylene-air pilot burner flame was left in contact

with the specimen throughout the run. While this had no Jcnown effect on the

results obtained, it did use fuel, and it did damage the specimen frame and

the substrate. It seemed advisable to limit flaming ignition contact time

either to 10 minutes or until the specimen flame goes out for times less than

10 minutes. This was an arbitrary decision supported in part by the data of

table 4 in which ignition times of 2 minutes and 5 minutes were studied. As

the data indicate, no effect was observed. Having defined propane as the

standard fuel for the pilot burner, limiting the ignition time to 10 minutes

8
and extinguishing the pilot burner will increase the number of tests that can

3 be run with one Bernz-O-Matic TX-101 fuel bottle to 75. The bottle is good

for 15 hours continuous burning. Assuming a conservative figure of 12 minutes

pilot burner time per test gives five tests per hour of fuel supply or 75

total from one TX-101 bottle. The standard flame for the tests is one having

a blue inner core length of 1.3 cm (1/2 in).

4.7 Specimen Geometry Effect

In developing guidelines for use of the Flooring Radiant Panel Test, the

need for tests of smaller-than-standard specimens became apparent at an early

stage. Critical radiant flux data on carpet remnants from three serious

corridor type fires were available in the Flammable Fabrics Accident Case and

Testing System file. These were clean, new condition samples but in two

instances insufficient material was available to test at the standard specimen

size, i.e., 20 x 100 cm. An exploratory study of the effect of specimen size was therefore initiated. As a first step, width and length effects were

investigated on carpets that were in good supply at NBS (table 7) . It was

found that a 5.1-cm (2-in) wide strip, pieced together in 30- to 39-cm

('^12- to 15-in) segments gave essentially the same results as the full size

specimen. With this relationship established, 5.1-cm (2-in) wide strip specimens from the Harmer House, Marietta, Ohio, and Baptist Towers, Atlanta,

Georgia, samples wore bonded to and along the center li.no of; 0.(t4-cm (l/4-ln)

cement asbestos board substrates and tested.

Sufficient material was available from the Pioneer Hotel, Tucson, Arizona,

sample so that full size specimens could be run. The carpet in this instance

was mounted over rubberized jute cushion pad so that the assembly was representative of the actual installation. All three carpets, i.e.. Marietta,

Atlanta, and Tucson, burned the full 100-cm test distance to give critical

radiant flux levels of less than 0.1 W/cm^ (table 8) . A radiant flux of

0.1 W/cm^ approximates the incident radiant energy from the sun at the surface

of the earth at noon on a clear summer day.

Certain commercial equipment, instruments, or materials are identified in

this paper in order to adequately specify the experimental procedure. In no case does such identification imply recommendation or endorsement by the

National Bureau of Standards, nor does it imply that the material or equipment identified is necessarily the best available for the purpose.

9
5. APPARATUS DESIGN, 5.1 ENGINEERING, AND DEVELOPMENT

Safety Precautions

The possibility of a gas explosion in the test chamber mandates that

suitable safeguards consistent with sound engineering practice be installed in

the panel fuel supply system. The initial NBS chamber handled this requirement

by providing a gas feed cut off activated by air supply failure. When this

3 3 failure occurs, a Honeywell Gas Pressure Sensing Switch shuts off a Maxon

Series 808-0 manual reset valve on the gas line. Other laboratories have used

fire sensors directed at the panel surface that stop fuel flow when the panel

flame goes out. The new NBS chamber uses a commercial gas water heater or gas-fueled furnace pilot burner control thermostatic shut off which is activated when the gas supply fails. This is a low cost reliable approach which

has been demonstrated to be effective. Undoubtedly, there are other devices

that will handle the need; however, note that manual reset is a requirement

of any safeguard system used.

In view of the potential hazard from products of combustion, the exhaust

system must be so designed and operated that the laboratory environment is

protected from smoke and gas. The exhaust capacity of the hood should be in

the 28.3 to 85 NTP m^ per min (1000 to 3000 CFM) range. Ceiling exhaust vents

are a recommended option. These will prevent combustion product buildup in

the laboratory. The operator should be instructed to minimize his exposure to

combustion products by following sound safety practice, e.g., ensure that the

exhaust system is working properly, wear a suitable mask, etc. A back-up

operator safety system is a breathable air apparatus (c.(j.. Mine Saroty

Appliance^ Cat. No. 10-46539, Demand Flow Air Lino Respirator wiUi "Cc^nir’a" Facepiece, or equivalent) located in the laboratory.

5.2

Fuel Control and Monitoring

Flow meters should be installed on the gas and air lines supplying the

radiant panel. Further, they should be calibrated to read volumetric flow

rate of each gas directly. The instruments used in the present NBS unit are

of the ball- tapered tube type and were obtained from Dwyer Industries, Inc.^,

Michigan City, Indiana.

5.3

Radiant Panel

The gas-air fueled radiant panel used in the test apparatus was obtained

from Radiant Heating Limited^, Foleshill Road, Coventry, England. The panel

is described as a No. 1 type radiant burner in cast iron container with a

10
heating surface of 30.5 cm x 45.7 cm (12 in x 18 in), pattern no. 2458. This

type is used in all testers built to date.

The blackbody temperature of the panel is determined with a calibrated

3 Honeywell Miniature Radiation Pyrometer, Model RL 2. The pyrometer is

positioned to sight on a line originating from the center point and normal to

the plane of the panel. It should be located at a distance from the panel

that will give a 25-cm (10-in) diameter target viewing area. This is about

1.37 m (54 in) for the NBS tester. The location and size of the pyrometer

target can be checJced by gridding the unheated panel surface with chalk marks

and running a signal trace using a small radiant energy source.

For one panel, the distribution of blackbody temperatures appeared to

the eye to be non-uniform. This was confirmed by measuring temperatures at 12

uniformly spaced locations on the panel surface (figure 2) . A cone was mounted

on the pyrometer to limit the field of view to a target diameter of 2.5 cm

(1 in) at a distance of about 20.3 cm (8 in) from the pyrometer to the panel.

One third of the lower segment of the panel was about 35 °C higher in blackbody

temperature than the mean temperature of the panel. The effect of this non- uniformity on the flux profile along the specimen plane was measured and found

to be insignificant. Profiles were run on the specimen center line and 6.3 cm

(2-1/2 in) on either side of the center line. The differences appeared to be

related primarily to chamber design, i.e., a slightly lower flux toward the

front of the chamber where the viewing window is located.

5.4 Radiant Energy Flux Profile Instrumentation

5.4.1 Requirements

Precise definition of the incident radiant flux profile generated by the

flooring radiant panel tester is the prime determinant of data quality. To

achieve this goal radiant energy flux instrumentation must: 1) be carefully

calibrated against a standard of known accuracy and precision, 2) respond to

the total incident energy spectrum, 3) maintain calibration for an extended

period of at least 12 months, and 4) have an uncertainty less than 5 percent.

5.4.2 Instrument Selection

The copper disc calorimeter used by Hartzell did not appear to meet

requirement 4) for low flux levels and was therefore ruled out. The SchmidtUoelter type total flux meter was selected for use in the flux profile

11
determination. The actual instrument used was Model No. 64-2-20 manufactured by

Med therm Corporation^, Huntsville, Alabama.

5.4.3 Calibration

The' calibration issue was investigated at an early stage and identified

as a problem in need of study and resolution. The calibration supplied by the

manufacturer was shown to vary from one transducer to another leading one to

postulate that the accuracy specification of + 3 percent in the manufacturer's

literature might be suspect. It was at this juncture that the NBS Optical

Radiation Group was called upon to calibrate two total flux meters and one radiometer with a CaFj window.

Good to excellent agreement between the NBS and Medtherm calibrations was achieved with the total flux meters; the radiometer calibrations differed by

12 percent. Appendix A is the NBS Optical Radiation Group report describing

the calibration procedure and summarizing the results. Note that this calibration is based on a single point radiant energy source that is very carefully

controlled and stabilized to within +0.6 percent of the true value. The source generates a flux of 0.150 W/cm^ (one solar constant). Transducer

linearity was assumed. This was subsequently confirmed in work that will be

discussed later in this section.

Following the completion of the initial NBS calibration work, each of the

laboratories with an operational flooring radiant panel apparatus was visited

to field calibrate its flux transducer (s) . The NBS total flux meter (serial

number 124421) served as the working standard for these calibrations. This

work was done during the Phase I NBS/MMFPA/CRI Interlaboratory Program and was a necessary step in the attainment of acceptable repeatability and reproducibility levels. This type of calibration, i.e., against a verified working

standard in a test chamber, has been continued by NBS for new flux meters

enroute to laboratories operating the flooring radiant panel apparatus. The

technique used is highlighted in appendix B which is the calibration report

sent to each laboratory. A digital voltmeter was used to measure flux meter

output. The range setting was 0 to 10 mv, reading to 0.01 mv. Table 9 summarizes the results of this calibration program for the period January

through July 1975.

As noted earlier in this section, the NBS Optical Radiation Section

calibration of the NBS total flux meter was a single point calibration, tlie single point being nominally one solar constant incident on the flux meter.

The desirability of a multi-point range bracketing calibration which had been

12
apparent since project inception was realized in early 1974. Through a contact at Purdue University's Thermophysical Properties Research Center,

arrangements were made with Goddard Space Flight Center, Greenbelt, Maryland,

to have the NBS working standard total flux meter calibrated at five points

spaced at appropriate intervals over the 0 to 1.2 W/cm^ service range of the

transducer. The radiation source was a xenon lamp beam directed to an optical

3 bench apparatus on which an absolute radiometer (Kendall Mark IV , High Intensity Radiometer, JPL) and the total flux meter were mounted. For each radiant

energy output setting, the reference standard radiometer was located in the

beam path and an output reading taken. It was then moved out of the path and

the total flux meter moved in for a reading. Table 10 shows the average values

obtained and the linearity of the calibrated flux meter.

Subsequent to the completion of this test method development, arrangements

were made with the Radiometric Physics Division (534) at NBS for a similar

calibration service.

5.5 Chamber and Stack Thermocouples

The two thermocouples recommended in the proposed procedure have as their

prime function monitoring chamber operation before, during and after a test.

The data generated are not routinely reported. For minimum maintenance, i.e., ease of cleaning, these should be 0.32-cm (1/8-in) diameter stainless steel

sheathed grounded junction chromel-alumel thermocouples.

5.6 Flaming Ignition Source - Pilot Burner

A premixed acetylene-air pilot burner was used as the flaming ignition

source in the previous work and throughout most of this project. It was and

is a satisfactory source from the standpoint of performance. Its relatively

high intensity flame ignited all materials that could be ignited and that

would propagate fire. However, because of industrial safety regulati6ns, this

burner was replaced in several laboratories by other premixed or diffusion

burners using natural gas or propane. The interlaboratory program results

indicated that certain pilot burners were probably operating below the threshold ignition energy levels for some materials and that a uniform, relatively

high intensity flaming ignition source was needed. In addition to the stated

performance need, the improved pilot burner had to meet the safety requirements

noted above.

13
The second generation and universally acceptable pilot burner finally

adopted satisfies these requirements. It is a commercial propane venturi

torch (Bernz-O-Matic TX 101^ or equivalent) with an axially symmetric burner

tip having a propane supply tube with an orifice diameter of 0.0076 cm (0.003

in) . It is positioned so that the flame generated will impinge on the center

line of the specimen at the zero reference point and at right angles to the

specimen length.

5.7 Specimen Mounting System

The specimen mounting frame developed in the Hartzell project was used

throughout the standardization program. It did a satisfactory job and would

be difficult to improve upon in any important way. Quick connect-disconnect

fasteners were a minor improvement feature incorporated in later units

manufactured commercially.

The specimen transport system used in the 1972-73 project was sound and

quite satisfactory. The commercial unit currently available uses a lighter,

less rigid design with substantially greater free air access area around the

specimen. The latter is of the order of 3225 cm^ (500 sq in). Initially, the

NBS chamber air access area was about 970 cm^ (150 sq in) . It was increased

to 1950 cm^ (300 sq in) prior to the start of the Phase I NBS/MMFPA/CRI

Interlaboratory Program. There is no evidence to indicate that the size of

this area has a significant effect on results, a conirlusion which has been

borne out in subsequent interlaboratory programs.

5.8 Chamber Details

The chamber as used throughout this investigation is the same as in the

earlier program. The sheathing was upgraded for durability reasons to a medium

density marine board consisting of calcium silicate asbestos fiber of 0.58 g cm"

(36 lb ft ^) density and 1.3 cm (0.5 in) thick. This was an improvement

recommended by Hartzell.

To streamline operations and improve the safety of the chamber to a minor

degree, the small bottom-panel door was hinged to open downward. This change

simplifies chamber construction. To make access to the radiant panel and

chamber thermocouples easier, the top portion of the front panel was hinged

to open up. This change has proven to be a good one and has been incorporated

in one commercial unit.

14
A view window 30 cm (12 in) x 16.5 cm (6-1/2 in) was added at the low

flux end of the chamber. This enhanced the observational capability and added

a new photographic record potential.

6. NBS DATA ON FLOORING SYSTEMS

The major impact of the Flooring Radiant Panel Test is expected to be in

the carpet field. Consequently, the prime data generating effort was directed

at carpeting systems. However, since the test is designed to deal with all

flooring systems, several other types of flooring products were evaluated.

Among these were red oak, vinyl asbestos tile, resilient vinyl roll goods,

and urethane wear surface vinyl cushion sheet flooring. In each instance

every effort was made to build the specimen so that it simulated field practice.

Thus, the red oak hardwood flooring strips were nailed to a 1.59-cm (5/8-in)

plywood subfloor over building paper, then sanded, sealed, and waxed. The oak

was tested at a moisture content of about 7 percent (50 percent R.H. equilibrium) . The vinyl asbestos tile was bonded to 0.64-cm (1/4-in) thick cement

asbestos board. Data on the red oak, vinyl resilient roll goods, and urethane

surfaced vinyl, previously cited in the section on preheat, are shown in

table 6. All of the vinyl asbestos tile samples gave values greater than

1.1 W/cm^ (2-min preheat). Figure 3 is an overview chart showing the relative

position on the critical radiant flux scale of all of the flooring materials

tested during this investigation. The rank ordering would appear to be con- sistent with field experience for this group of products. The effect of

cushion pad is shown in tables 5, 11, 12, 13, 14, and 16. It is important to

note that the wool carpets tested (tables 12 and 16) showed little or no decrease in critical flux levels between the samples tested with and without

cushion pads. This is in marked contrast to most of the synthetic fiber carpets tested where the pad reduced the critical flux value to a significant

degree. Table 11 confirms this observation which further shows that this

particular carpet, a tufted nylon 6,6, was relatively insensitive to cushion

pad type

.

7. rNTERLABORATORY PRCKIUAMS

7 . 1 Phase I NBS/MMFPA/CRI Interlaboratory Program

The Phase I NBS/MMFPA/CRI Interlaboratory Program was the first major

study of the reproducibility and repeatability of the Flooring Radiant Panel

Test. In this project, thirteen laboratories tested eight carpet systems in a classic factorial design with replication at the three level. The carpets in

this program were primarily for residential use. All specimens were mounted

over 0.64-cm (1/4-in) cement asbestos board with a 1.3-cm (1/2-in) calcium

15
silicate/asbestos backer board. The carpet systems were held in the mounting

frame by clamp force only, i.e., no adhesive bonding.

7.1.1 Sample Selection

Sample selection was handled by a committee composed of fiber and carpet

manufacturers drawing on the NBS data listed in table 12. The six carpets

were chosen to:

1. Be representative of current commercial practice.

2. Include thermoplastics and char formers.

3. Cover a broad critical flux range.

The carpets ultimately selected were:

a. Acrylic - level loop

b. Nylon - level loop

c

.

Wool - plush

d. Nylon - cut pile print

e

.

Polyester - shag

f Acrylic - plush

The specimens were cut, numbered, randomized, and sent to each of the

participating laboratories by Tennessee Eastman Company. The procedure was based on the July 1974 NBS draft, i.e., no preheat.

7.1.2 Testing Phase

The first two carpets were tested with and without a 55-oz/yd^ rubberized

jute pad. All laboratories operated their testers at the "C" condition, i.e.,

panel apparent blackbody temperature about 500 °C and a radiant flux of 0.50

+ 0.02 W/cm^ at the 40-cm point on the specimen plane. During this program

it was established by Tennessee Eastman statisticians that the NBS field

calibration of all flux measuring instruments upgraded the quality of the

data to an acceptable reproducibility level. As noted earlier, laboratories

with total flux meters generated generally acceptable data prior to field

calibration. The data from those laboratories with CaF 2 windowed radiometers

would have been lost had there been no field calibration. Thus, definition

of the preferred flux measuring instrumentation was an important result of

this "calibration" experiment.

16
The data obtained from the participating laboratories are given in

table 13.

7.1.3 Statistical Analysis

The statistical analysis of the data was done by Dr. John Mandel at NBS

using the proposed ASTM E 11 procedure for interlaboratory evaluation studies.

His analysis showed the test to be suitable for use as a standard. Defining

a test result as the average of three replicate determinations, the "repeatability" [10] (within-laboratory variability) was about 20 percent of the

measured value and the "reproducibility" [10] (among laboratory variability)

was of the order of 35 percent of the measured value; these variabilities are good for fire tests, particularly when compared to the ASTM E 84 Tunnel Test

and the UL 902 Chamber Test for carpets. When precision for all Lhic'C methods

is calculated by the same procedure, the Flooring Radiant Panel '1'esL is shown

to have the best repeatability and reproducibility [11]

.

This program pointed up a minor potential problem in the conduct of the

test uniformity of pilot ignition energy among the participating laboratories.

Laboratory 4 experienced ignition difficulties with the polyester carpet CT4644-5. Therefore, this data blocJc was replaced with the "all-laboratory"

mean value of 0.40 W/cm^. Laboratory 9 (on sample 2) had some trouble also.

This issue was resolved by the use of a commercial propane pencil flame

jeweler's torch.

7.2 Phase II NBS/MMFPA/CRI Interlaboratory Program

The Phase II NBS/MMFPA/CRI Interlaboratory Program was an extension and

expansion of Phase I. The procedure used was that of the March 13, 1975 draft,

i.e., a 2-minute preheat.

7.2.1 Sample Selection and Testing

Only carpets that were sold to what is identified as the contract market

were selected by the CRI/MMFPA Committee for this evaluation. Carpets in this

category are used in regulated public occupancy buildings, e.g., hospitals,

nursing homes, hotels, office buildings, apartment buildings, et al. The

program was divided into two parts. Part A was a classic 13-laboratory, 10-

carpet systems interlaboratory factorial design experiment with replication at

the three level. Part B involved an additional 64 carpet systems with each of

the 13 laboratories testing only a fraction of the total specimens. The Part B

selection process has as its objective that the carpets be representative of

17
the 800+ products of current commercial importance. For the Phase II program,

all carpets tested without separate cushion pad were bonded to the 0.64-cm

(1/4-in) cement asbestos board with adhesive. Carpets tested with separate

cushion pad were held in place by the clamping force of the mounting frame

assembly. The standard 1.3-cm (1/2-in) backer board was used in both cases. The 2-minute preheat step was used in all Phase II testing as prescribed in

the June 9, 1975 draft of the proposed procedure.

7.2.2 Statistical Analysis

The statistical analysis of the data was again done by Dr. Mandel using

the proposed ASTM E 11 procedure with only Part A of the Phase II program being

amenable to statistical treatment. Prior to the statistical work, the data were carefully examined for anomalies and for validity. Where critical radiant

flux values greater than 1 W/cm^ were reported, e.g. , one value out of the

three data points as >1 W/cm^ , it was decided to replace the high value

(equivalent to a "did not ignite") by a number which was the mean of the two

remaining data points. The basis for this judgment and action was the earlier

observation that the energy of the flaming ignition source does affect the

critical flux level obtained for dif f icult-to-ignite carpets. The >1 W/cm'

critical flux value where the other data points were significantly lower is

identified with a marginal flaming ignition energy source. In this program

as in the first, a variety of pilot burner geometries and fuels was used.

When all radiant panel laboratories have converted to the propane pencil flame

torch system, this problem is expected to disappear. The Part A data are listed in table 14. Numbers in parenthesis are replaced data points.

The analysis based on eight materials showed that the repeatability and

reproducibility levels were of the same order as those of the Phase I experiment. It is appropriate to note that a repeatability of 20 percent approximates a within-laboratory coefficient of variation of 7 percent and that a reproducibility of 35 percent approximates a between- laboratory coefficient of

variation of 12.5 percent.

7.2.3 Optimum Number of Specimens

The statistical study was broadened for Phase II Part A to deal with the

issue of optimum number of specimens needed to generate a meaningful test

result. Repeatability and reproducibility levels achieved with one, three,

and ten specimens contributing to the test result were determined. This work

confirmed that three specimens were necessary and desirable (table 17)

.

18
7.2.4 Contract Carpet Performance

The data of Part B are summarized in table 16. As already indicated,

they are not amenable to statistical treatment. Average values are presented

which may include data from four up to seven laboratories. Although specimen

distribution was randomized, the lack of a formal experimental plan precluded

formal analysis. The data are useful for the picture they give of the critical radiant flux spectrum of the contract carpet mix. Figure 4 shows in a histogram treatment that carpets are available that cover the entire radiant

flux range of the flooring radiant panel tester - and beyond, at both the low

and high radiant energy limits. Note from table 16 that most of those carpets

when tested with and without a pad give critical radiant flux values significantly lower when tested with an intervening cushion pad.

7.3 Concluding Statement

The Interlaboratory Programs have demonstrated the ability of the Flooring

Radiant Panel Test to provide good differentiation among flooring systems at

an acceptable repeatability and reproducibility level.

8. CONCLUSIONS

The Flooring Radiant Panel Test is now ready for use as a standard test

for floor covering systems with these demonstrated advantages over the ASTM

E 84 Tunnel Test, the UL 992 Chamber Test, and the NBS Model Corridor:

1. The fire property measured is one important component which must be

considered in any analysis of fire risk from corridor fires.

2. Test results are expressed in terms of a quantitative energy flux

level

.

3. The total flooring system is tested in the horizontal plane as u;;ed

.

4. Reproducibility and repeatability are relatively good.

5. The apparatus is compact and suitable for use in a standard laboratory

space

.

6. The test procedure is simple and straightforward, with due consideration

to necessary calibration procedures.

9 . ACKNOWLEDGEMENTS

The work reported herein represents the results of a major team effort

involving the NBS Center for Fire Research and the several associations and

companies that make up the floor covering system industry. The Man-made Fiber

Producers Association, together with the Carpet and Rug Institute, played key

19
roles in the Interlaboratory Programs with member firms supplying test samples

and participating in the experimental program. Their help was invaluable and

is hereby acknowledged. Other significant contributors were the Wool Bureau

and the Resilient Tile Institute. Their inputs were important and much

appreciated.

The encouragement and guidance of NBS Center for Fire Research management

provided the impetus and direction needed to bring the project to a successful

conclusion. Special thanks are due I. A. Benjamin for his support. C. Huggett

made important contributions. The professional assistance of J. Quintiere was much appreciated. And to engineering’ aid David Swanson, who handled the

experimental work load, a special word of thanks is appropriate.

10. REFERENCES

[1] Hoenack, A., Use of Carpeting in Hospitals, Directive, Division of

Hospitals and Medical Facilities, U.S. Public Health Services,

March 5, 1965.

[2] Yuill, C. H. , Floor Coverings: What is the Hazard?, Fire J., Vol. 61,

No. 1, 11-19 (1967)

[3] Subject 992, Standard Method of Test for Flame-Propagation Classification

of Flooring and Floor Covering Materials, Underwriters Laboratories Inc.

(Feb. 1971).

[4] Denyes, W. and Quintiere, J., Experimental and analytical studies of

floor covering flammability with a model corridor, Nat. Bur. Stand.

(U.S.), NBSIR 73-199 (May 1973).

[5] Hartzell, L. G., Development of a radiant panel test for flooring

materials, Nat. Bur. Stand. (U.S.), NBSIR 74-495 (May 1974).

[61 Quintiere, J., Some Observations on Building Corridor Fires, Proceedings

of the Fifteenth Symposium (International) on Combustion, The Combustion

Institute, Pittsburgh, Pa., 163-174 (1975); held in Tokyo, Japan, .1974 .

[7] Benjamin, I. A., and Adams, C. II., Proposed criteria for the us(> (jI I. he

critical radiant flux test method, Nat. Bur. Stand. (U.S.), NBSIR 75-950

(Dec. 1975).

20
[8] American Society for Testing and Materials E 648-78, Standard Test

Method for Critical Radiant Flux of Floor Covering Systems Using a Radiant Heat Energy Source, 1916 Race Street, Philadelphia, Pa. 19103.

[9] Quintiere, J. and Huggett, C. , An evaluation of flame spread test

methods for floor covering materials, 59-104, Butler, M. J. and

Slater, J.A., editors, Fire Safety Research, Nat. Bur. Stand. (U.S.),

NBS Special Publication 411 (Nov. 1974)

.

[10] Mandel, J., Repeatability and Reproducibility, Materials Research and

Standards, Vol. 11, No. 8, p. 8 (Aug. 1971).

[11] Zabawsky, Z., private communication.

21
Table 1. Position of the flux meter

Flux profiles run with flux meter protruding 0.96 cm (0.38 in)

above dummy specimen and 0.13 cm (0.05 in) above specimen

Panel blac)cbody temperature 508°C

Distance along

specimen plane Flux meter height above dummy specimen

cm 0.96 cm (0.38 in) 0.13 cm (0.05 in)

W/cm'^ W/cm

10 1.17 1.15

20 0.95 0.95

30 0.71 0.72

40 0.49 0.51

50 0.34 0.36

60 0.24 0.25

70 0.17 0.17

80 0.13 0.14

90 0.11 0.11

22
1) i s Lance cm

Table 2. Effect

on the

Flux meter

I’anel on Pilot up

of the acetylene-air

radiant energy flux

#124421; blackbody -

I'anel on Pilot down

pilot

profile

490°C

flame

P.iiu'l on No pilot

, " W/cm^ W/cm^ W/cm^

10 1.05 1.07 1.07

20 0.88 0.87 0.87

30 0.64 0.65 0.64

Distance

cm

Panel off

Pilot up

Panel off

Pilot down

W/cm^ W/cm^

10 0.01 0.01

20 0.01 0.01

30 0.01 0.01

23
Table 3. Effect of 2- and 5-minute preheat times

on seven wool carpet samples

Critical radiant flux, W/cm^

Sample identification No preheat 2 min preheat 5 min preheat

WB - 1 >1.05 0.58 0.61

level loop, face wt 46 oz. 0.59 0.56 0.68

tufted >1.05 — 0.66

X — 0.57 0.65

a — 0.07

V — 11.1%

WB - 2 0.58 0.35 0.39

plush, face wt 75 oz. 0.63 0.36 0.38 woven 0.57 — 0.38

X 0.59 0.35 0.38

a 0.03 0.01

V 5.4% 1.5%

WB - 3 >1.05 0.70 0.73

level loop, face wt 44 oz. 0.79 0.64 0.76

tufted 0.81 — 0.75

X — 0.67 0.75

a — 0.02

V — 2.0%

WB - 4 1.16 5768

plush velvet, face wt 64 oz. 1.17 0.69 woven 1.02 0.74

X 1.12 0.70

0 0.08 0.03

V 7.5% 4.6%

WB - 5 0.70 0.34

plush, face wt 44.5 oz. 0.56 0.45

tufted 0.58 0.41

X 0.61 0.40

0 0.08 0.06

V 12.4% 13.9%

WB - 6 1.18 0.75 0.73

level loop, face wt 44 oz. 1.18 0.78 0.77 woven 1.15 — 0.73

X 1.17 0.76 0.74

0 0.02 0.02

V 1.5% 1.1%

WB - 7 0.64 0.56

level loop, face wt 68 oz. 1.10 0.57

tufted 1.12 0.55

X 0.95 0.56

a 0.27 0.01

V 28.6% 1.8%

X = arithmetic mean

a = estimated standard deviation

V = coefficient of variation

24
Table 4.

Sample

identification

WB-1

Wool, level loop

face wt 46 oz,

tufted

NC-W

Nylon, 6,6, BCF, level

loop

(RFY-74-14)

white

NC-B

Nylon 6,6, BCF, level

loop

(RFY-74-14)

black

900-20

Acrylic, level

loop, face wt 42 oz,

tufted

900-31

Polyester, level loop

face wt 42 oz

^Burn duration

Effect of preheat and ignition flame

contact time on typical carpets

Pilot flame Critical radiant

Preheat contact time flux

time, min min W/cm'’

0

3

35

5 10

10

7.2^ >1.05, >1.05, 0.60

0.74

0.63

0.61

0.66

0.59

0.57

0 2, 5, 9.1^ 1.1, 0.98, >1.1

3

35

5 10

10

25

2

5

2

5

>1.05

>1.05

>1.05

>1.05

>1.05

>1.05

0 2, 5, 17.3^ 0.78, >1.1, 0.96

33

55 10

10

2

5

25

2

5

>1.05

>1.05

>1.05

'>1.05

>1.05

>1.05

0

335

5 10

10

13.4 + 0.06^

2

5

25

2

5

0.42 + 0.01

0.38

0.43

0.44

0.40

0.39

0.42

0

3

355 10

10

40.3 + 3.3

2

52

5

2

5

0.35 + 0.04

0.36

0.36

0.33

0.39

0.41

0.34

25
Table 5. Effect of pad type and preheat on tufted acrylic carpet

Critical flux Critical flux

(W/cm^

)

(W/cm^

)

Sample identification No preheat 5 min preheat

No pad^ 0.64 0.65

No pad 0.74 0.62

No pad 0.69 0.63

X 0.69 0.63

a 0.05 0.02

V 7.2% 3.2%

Hartex synthetic fiber felt 0.38 0.39

Hartex synthetic fiber felt 0.37 0.45

Hartex synthetic fiber felt 0.60 0.39

X 0.45 0.41

a 0.13 0.03

V 28.9% 7.3%

72 oz waffle 0.56 0.47

72 oz waffle 0.49 0.49

72 oz waffle 0.61 0.44

X 0.55 0.47

o 0.06 0.03

V 10.9% 6.4%

Rubberized hair jute 0.43 0.31

Rubberized hair jute 0.40 0.39

Rubberized hair jute 0.50 0.33

X 0.44 0.34

0 0.05 0.04

V 11.4% 11.8%

Foam, rebonded urethane 0.36 0,35

Foam, rebonded urethane 0.45 0.43

Foam, rebonded urethane 0.41 0.40

X 0.41 ^731'

0 0.05 0.04

V 12.2% 10.4%

X = arithmetic mean

o = estimated standard deviation

V = coefficient of variation

^ Carpet mounted directly on cement asbestos board

26
Table

6.

Test

data

on

wood

and

resilient

flooring

products

ro vD ^ <Ti un ro

o

roo o

o

-p •Huu

4J

fC0) x:

(Upa

o> m ^ ro

a> m m m ^

o o o o o o o

m

o

O2

o C5 r*- 54 00 o > u ro T5 05 \ o o O o O o • 04 •H O •o 05 54 > in

rH LT> ro (N VP o c 05 X T5 e o o O o o O o S-l z 03 o rH C 05 rH o

M m m O' a, 3 X3 It 'V X

o o o o O o o 05 ro p 4-5 03 0 C 05 05 c s O 0 rH X E It (55 rH 54 0 u p p It O • c 05 W (55 •H 05

(1) M 0) 0) rH c o •H <H w 0) 03 a

-p >1 O >1 o >1 o 03 •>» 54 CQ X C 03 a (0 03 03 03 It 03 0 X c p O' u o 05 <c o 03 04 03

•H r—

1

n XI rH X! u +j p 05 c 05 tNX u (NO •» 0

M 03 05 05 >1 •H X a: X K O 03 • 0

U p E p E p E <H 5-1 4-5 03 •H 05 54 05 O' s w fO 03 03 03 03 03 u 3 4J rH U <4-1 O' 05 cffi 0 X TS >1

0) Oi 0 QJ o 0) o 3 03 03 0 > > 03 iH Q 5 <4-1 > ? IW 05 04 X <? X 0 <? X 3 X a

o

c c m u •H

54 o o o O

c c c O T3 'H •H •H 1—1 05

54 54 54 X X 03 0 0 O (55 05 o O o X •H X

'—

I

rH 1—1 e c 05 X X X e -r4 -r4 X X C X X X (0 c -r4 05 0 05 3 X

05 05 e X X X X c - -

(55 (fl (55 05 e •H 03 03 rH •H iH X rH 0 o a >1 >1 •H E c c c CO TS 03

03 •H •H •H cu 05 05 (n > > > cr: PS PS

!l 27
Table 7.

SpeciT.en

geometry

study

Small

specimen -

standard

specimen

equivalency

(No

preheat

unless

indicated) P

•H

'Vu

to 'Oc

<0 p0)

fio

:s

O •tj' r- in lO TT

V£> lA

VO V© oooo oooo ' I\

x:pc

4) £O 4) r-4

to •Hu

(0 >

x:p

XTC0) oooo ^ <N fN ^ OOOO TT CN fN 1-1 CQ CQ < < u u

CQ<o 0 0 0 p p p 1

T3

0) 'Oco 0) 73Co

Si

T3O

TJCo

Xi

KT • 0) O'

(n 0)

(/) f=0 eo 1 I m tn

ro

cj' 0 o

(0 (A E e u o 1 I m m m ro

O' O' O' O' O' O (D (U 0 O

(A tf) (A (A (A £ £ E E E 0 0 O O O 1 I I I I o o in ir> iTj (N <N rn m rn

O' O'

<U

O

(A (A E E

(J

O I I m m m ro

OOOOOOO OOOO

'O

•H5 EO

4)

r—

jQ

<d H

iQ > P

'O

•H

in in in in

in <n lo nivor*- ininmininmin minmin 1 c

Q)E

•Ho

4)a

<A *0p

Idc

to Eo\ m (N

O CN ^ O O O o o »P rn ^

VO NO VO VO VO <H 00 m VO m ^ ro ro

m ooooVOm fM ^

<N fN CN (N o o o o \

ClE

V)

aoo^ Vop 4; ««-( > o

4) P

a^j O 4) O P

r-i >14:i r~1 *J

(U

4>

NO o u a p fd O Xi 0 ^ 'H N £ O <0 •H • •H 0 4) ^ <N •> 00 jC V 41 <N vp 4) <N 4) 4J

*-1 >1 ^ fN VO IN (A vr > <N > <N P 3 1 1 3 41 4> 3 c: ^ O P 'T VO P rH P <-4 P »Q rH P C *H

-T <d 3 a s •T P «r "s '< f: vO C Ov c: (J* O' c li 1 •T 4> 0 0) m CO 0 4) 4> rn 0 4> 1 o 1 O 0 1 ^ 0 1 0 y 7* U P •r rH 0 m rH H O IQ >t to CQ 0 m iQ c >1 (Q O IM u C <4-1 2 » iw X C <P •H C <P a b

28
Table

8.

Test

data

on

carpets

from

actual

corridor

fire

cases

Cum 0 U O <0

•H £ > 0

0) 4-t

CQ CQA < < < u u u

CQ OQ ffla CQ CQ

uuu <<< << < 0 0 o u u u V u u > > > O 0 0 Q 0 Q 0 0 0

4J -*5 4J 4J -P T3 *0 'O

fO <0 IQ '0 'O 'O T3 '0 *0 Q« Q< Cu

0) 0) 0» Q) 0) 0

XJ *0 *0 *0 '0 T3

O 0 0 c c c C C C 4J 4J 4J 0 0 0 0 0 0 3 3 3 ^ i) •r^TTr^

«. «. « - * - U

U

U

T3 'O '0 'OH ’H

Q) 0 0 0) o o <0 *8 flj 4-> 4J 4J •P 4J ^ jz x: jz c c c c c c

0) 0 Q)

O 0) 0)

N

N

N £ £ £ £ £ £ 0 0 0

O' O' O' O' O' O'

0) o o 0 0)0

mmm

CO cn (A (0 CO (0

m

mm £ £ £ £ E £ u B u o u 0 0 0 0 O

T3

mmm

mm in

C

O

ao 'O

w 0 (0 ^ Qi o>

O >1

p

'O

a ^ H : VO <8 0 fl 0 18 <N

O

u pap •H XZ \ rH c O' a 0 O' a 0 o > 0 o >1 P 1 -0

El 4-> <H rH .P P 0 00 P

nj >1 c o c o > >S^ <8 CO c •H a *H <8 0 <*n 0

xi

CO fM 0

r* 4J O' COo

CO o p CO £ 0 o o (8 0 ^ O -P m <8 X 0 0 XZ C C u

•H Eh <8 • O o c 0 4J x: ^ > 0 N r* 0

(0 c o 4J P 4J 0 4J •H O' £ 3 0 CO 0 < z 0 P M O 0 o o •H UU X < u

CO

X CO (8 4J ^ o O -P Cl O' 0 p 11 o U ^ 4J flj C ^ -H 0 C nj 0 (8 0 X -P P O' 0 0 m 0 £ > -H CO 0 P c 0 • < u p C p 0 3-00 0 CO o u

18 0 18 0 rH 0 •H 3 0

Cu XUS Eh

XU

O

a

Q (8

29
Table 9 . Flux meter^ calibration log

Instrument

serial no. Lab

Med therm

calibration

NBS

calibration Date

/n -2 -Iv (W cm mv ) (W cm mv ) 3851 Ontario Research 0.207 0.199 5/14/75

3857 Bicjelow-Sanford 0.211 0.201 4/25/75

9943 Monsanto (TC) 0.284 0.293 3/3/75

48336^ Monsanto (MRC) 0.043 0.036 7/1/75

62444 Allied 0.227 0.215 1/9/75

99424 Celanese 0.217 0.202 1/24/75

99429 Brunswick 0.253 0.250 6/12/75

99431 Hoechst 0.209 0.197 6/3/75

99438 Bigelow-Sanford 0.212 0.195 1/15/75

99448 Celanese 0.191 0.184 1/22/75

99450 Hercules 0.201 0.187 1/24/75

99450 Hercules 0.201 0.185 6/3/75

99456 Brookline 0.234 0.207 2/14/75

^ Medtherm model no. 64-2-20 unless indicated otherwise

HY-CAL model no. R-8015-B-03-072

30
Table 10. Total flux meter calibration

Engineering Applications Branch

Goddard Space Flight Center

Radiant energy level, xenon source, as measured

by Kendall Mark IV High

Intensity Radiometer*^

Total flux meter output

Medtherm model no. 64-2-20 Conversion

serial no. 124421 factor

2 -2

W cm Millivolts W cm mv

X = 0.3444 + 0.0015 X = 1.263 + 0.007 0.2727

X = 0.5163 + 0.0015 X = 1.894 + 0.006 0.2726

X - 0.6491 0 . 0009 X - 2.38] + 0.005 0.2726

X = 0.7944 + 0.0008 X - 2.928 + 0.006 0.27J 3

X = 1.0984 + 0.0213 X = 4.043 + 0.098 0.2717

Jet Propulsion Laboratory, California Institute of Technology

31
Table 11. Effect of cushion pad types on critical

radiant flux for a nylon 6,6 carpet

Carpet samples from NBS-SPI Corridor Program

No preheat

Carpet code Cushion pad

Critical radiant

flux, W/cm^

J-4894 None

Style - level loop

Fiber - nylon 6,6

Backing, primary - polypropylene

secondary - jute

Face weight, oz/yd -22

Construction - tufted

0.26

0.23

0.22

0.24 + 0.02

J-4894 Rubber coated 0.12

Jute 55 oz/yd^ 0.13

0.12

0.12 + 0.01

J-4894 Virgin urethane 0.15

0.14

0.13

0.14 + 0.01

J-4894 Rebond urethane 0.18

0.16

0.15

0.16 + 0.02

J-4894 SBR waffle 0.13

0.14

0.13

0.13 + 0.01

H-4894 Integral 1/8" bonded 0.14

high density foam 0.13

0.13

0.13 + 0.02

32
Table 12. Data on Carpet and Rug Institute, Man-made Fiber Producers Association samples

No preheat

Code Style Fiber Backing Face weight

oz/yd^ Construction Pad Critical radiant^

flux, W/cm^ Comments

900-1 Level loop Wool 46 Woven None 0.91 + 0.2 3 . 7 min + 2.8 charred 33-36 cm

900-2 Plush Wool 42.5 Tufted None 0.56 + 0.07 6.1 + 1.0 min charred 30-38 cm

900-2 Plush Wool 42.5 Tufted Hair Jute

0.62 + 0.09

900-10 Shag Nylon 6 Nylon 6,6

24 Tufted None 0.39 + 0.09 46.7 + 17 min high uneven flame

900-10 Shag Nylon 6 Nylon 6 ,

6

24 Tufted Hair Jute

<0.10

900-11 Level loop Nylon 6,6 28 Tufted None 0.51 + 0.05 64.0 + 7.4 min

900-13 Level loop Nylon 6 38 oz foam 20 Tufted None 0.55 + 0.14 34.7 + 15 min

buckled, high

flame, smoke

900-15 Level loop Nylon 6,6 38 oz foam 14 Tufted None 0.23 + 0.06 70.4 + 20.7 min

buckled, heavy

black smoke

900-20 Level loop Acrylic 42 Tufted None 0.46 + 0.01 13.4 + 0.1 min melting 20-28 cm

900-21 Plush Acrylic Tufted None 0.22 + 0.01 12 + 0.8 min charred

900-30 Saxony plush Polyester 45.2 Tufted None 0.30 + 0.03 71.2 + 3.5 min heavy black smoke

900-30 Saxony plush Polyester 45.2 Tufted Hair Jute

<0.15 Very heavy black

smoke

900-31 Level loop Polyester 42 Tufted 0.39 + 0.04 40.3 + 3.3 min thick black smoke

900-32 Random shear Polyester 37 Tufted 0.22 + 0.01 76.7 + 10.4 min heavy black smoke

900-32 Random shear Polyester 37 Tufted Hair Jute

<0.10 High flame, black

smoke

900-40 Level loop Polypropylene 22 Tufted <0.10 99.8 + 8.7 min high flame, black smoke

^ Total flux meter #321223 used in flux profile determination

33
Table 13. Phase I NBS/MMFPA/CRI Interlaboratory Program data No preheat

Sample identification

Laboratories

1. CT-4644-1

100% acryliclevel loop

(900-20)

IP. CT-4644-1 + pad^

2. CT-4644-2

nylon, level loop (900-U)

2P. CT-4644-

+ pad

Critical

2 3. CI^4644-3 5 wool plush

(900-2)

Radiant Flux, W/cm^

CT-4644-5

polyester

(900-30) shag

6. CI^4644-6 7. acrylic plush

(900-21)

CT-4644-7 nylon 6 cut pile ' print

i

1 0.48 0.25 0.96 0.31 0.56 0.38 0.16

"1 0.56 0.46 0.24 0.86 0.29 0.53 0.31 0.18 0.60 0.44 0.29 0.76 0.34 0.55 0.32 0.17 0. 51 '

2 0.60 0.32 0.64 0.43 0.78 0.36 0.20 0.64 0.49 0.24 0.75 0.32 0.68 0.32 0.23 0.60 0.46 0.32 0.71 0.36 0.58 0.52 0.25 0.70

3 0.51 0.36 0.71 0.36 0.67 0.34 0.26 0.64 0.49 0.35 0.71 0.37 0.50 0.36 0.28 0.67 0.48 0.32 0.70 0.42 0.80 0.40 0.26 0.68

4 0.49 0.24 0.71 0.27 0.55 0.40 0.19 0.45 0.44 0.30 0.84 0.35 0.84 0.40 0.20 0.49 0.44 0.21 0.63 0.33 0.63 0.40 0.17 0.55

5 0.38 0.31 0.66 0.32 0.66 0.43 0.30 0.76 0.42 0.35 0.71 0.35 0.64 0.37 0.29 0.66 0.45 0.34 0.84 0.37 0.66 0.47 0.29 0.66

6 0.43 0.22 0.60 0.32 0.64 0.42 0.21 0.52 1 0.42 0.28 0.61 0.35 0.49 0.37 0.20 0.55 0.40 0.36 0.63 0.38 0.59 0.30 0.19 0.55

7 0.40 0.28 0.58 0.31 0.58 0.52 0.24 0.60 0.39 0. 32 0.80 0.29 0.51 0.51 0.23 0.64 0.43 0.30 0.84 0.27 0.69 0.54 0.23 0.69

8 0.47 0.40 0.76 0.40 0.73 0. 33 0.35 0. 59 0.43 0.34 0.98 0.29 0.66 0.64 0.31 0.59 0.64 0.39 0.74 0.29 0.73 0.24 0.30 0.58

9 0.50 0.27 0.80 0.26 0.60 0.60 0.25 0.50 0.52 0.26 0.65 0.32 0.77 0.48 0.17 0.48 0.42 0.26 1.23 0.28 0.82 0.33 0.19 0.60

10 0.49 0.30 0.74 0.43 0.58 0.49 0.22 0.62 i 0.44 0.24 0.95 0.31 0.65 0.60 0.21 0.57 0.53 0.31 0.90 0.42 0.53 0.54 0.21 0.63 U 0.39 0.30 0.74 0.25 0.53 0.20 0.19 0.67 0.49 0.32 0.77 0.30 0.55 0.32 0.19 0. 33 0.57 0.22 0.76 0.32 0.47 0.34 0.21 0.58 1

12 0.48 0. 34 . 0.66 0.39 0.60 0.39 0.18 0.53 _

0.47 0.27 0.59 0.36 0.85 0.46 0.26 0.51 0.42 0.37 0.71 0.34 0.62 0.38 0.22 0.52

13 0.50 0.28 0.78 0.31 0.62 0.34 0.21 0.78 ’

0.57 0.27 0.85 0. 34 0.68 0.39 0.22 0.74 0.42 0.31 0.85 0.33 0.74 0.25 0.21 0.52 9

Mean 0.47 0.30 0.76 0.34 0.64 0.40 0.23 0.59 M

Std. deviation 0.04 0.04 0.09 0.03 0.07 0.07 0.04 0.07 1

Coeff. of 7.5% 12.4* 11.3% 10.2% 10. 3% 18.0% 18.6% 11.3% .1 variation

^ Type II rubber coated jute DD-C-001023 (GSA-FSS)

j

i

34
Table 14. Phase II Part A NBS/MMFPA/CRI Interlaboratory

Two-minute preheat

Sample identification

Program data'

101 wool, 202 nylon 202 + 207 nylon 215 nylon 301 acrylic, 301 + 402 polyester. 507 poly- 601 acrylic/

level loop, 6,6 level pad (b) 6, level 6,6 cut level loop, pad (b) level loop. propylene. nylon, level

velvet. loop. loop. loop. tufted, jute tufted, jute level loop. loop, tufted latex tufted. tuft^. TOven, backing backing tufted. 37 oz/yd^.

backing

46 oz/yd^

jute

backing

28 oz/yd^

(a)

16 oz/yd^

integral foam backing

latex backing

34.7 oz/yd^

42 oz/yd^ 42 oz/yd^ jute

backing,

28 oz/yd^

+ pad

integral foam - FR

backing

Laboratories (a) (b) Critical radiant flux, w/cm^

1 0.87 DNI 0.18 0.16 0.73 0.59 0.32 0.69 <0.10 0.64 0.80 DNI 0.23 0.24 0.65 0.59 0.30 0.69 <0.10 0.77

0.80 DNI 0.18 0.20 0.82 0.56 0.21 0.67 <0.10 0.75

2 0.87 DNI 0.17 0.16 0.77 0.61 0.25 0.79 (1.10) <0.10 0.63

0.82 DNI 0.23 0.22 0.78 0.64 0.21 0.81 <0.10 0. 52 0.86 DNI 0.24 0.23 0.78 (1.06) 0.59 0.25 0.76 <0.10 0.66

3 0.91 DNI 0.23 0.21 0.58 0.60 0.26 0.61 <0.10 0.56

0.87 DNI 0.20 0.29 0.72 (DNI) 0.56 0.26 0.66 <0.10 0. 55 0.89(1.01)^^ DNI 0.19 0.24 0.85 0.61 0.29 0.81 <0.10 0.54

4 0.85 DNI 0.17 0.24 0.53 0.67 0.23 0.70 <0.10 0.52 0.86(1.04) DNI 0.17 0.12 0.63 0.59 0.20 0.79 <0.10 0.42 0.89 DNI 0.16 0.16 0.76 0.58 0.25 0.72 <0.10 0.62

5 0.76 DNI 0.20 0.20 0.82 0.64 0.24 0.64 <0.10 0.76

0.90 DNI 0.21 0.17 0.85 0.77 0.26 0.68 <0.10 0.73 0.83(1.09) DNI 0.24 0.17 0.84 (DNI) 0.97 0.22 0.72 <0.10 0.78

6 0.78 DNI 0.16 0.17 0.47 0.59 0.20 0.72 <0.10 0.51

0.67 DNI 0.20 0.26 0.56 0.60 0.19 0.54 <0.10 0.52

0.68 DNI 0.15 0.20 0.56 0.51 0.19 0.56 <0.10 0.52

7 0.92 DNI 0.20 0.18 0.61 0.64 0.21 0.68 <0.10 0.68 0.72 DNI 0.22 0.22 0.57 0.55 0.24 0.63 <0.10 0.64 0.72 DNI 0.17 0.15 0.64 0.51 0.25 0.57 <0.10 0.68

8 0.94 DNI 0.15 0.15 0.49 0.53 0.20 0.68 <0.10 0.74 0.87 DNI 0.16 0.14 0.51 0.57 0.21 0.63 <0.10 ‘ 0.83 0.83 DNI 0.14 0.21 0.52 0.49 0.22 0.57 <0.10 0.74

9 0.84 DNI 0.16 0.19 0.57 0.54 0.24 0.77 <0.10 0.66

0.75 DNI 0.10 0.17 0.65 0.60 0.17 0.59 <0.10 0.67

0.93 DNI 0.17 0.11 0.52 0.54 0.17 0.68 (1.04) <0.10 0.56

10 0.97 DNI 0.25 0.21 0.98 0.67 0.36 0.56 (DNI) <0.10 0.87 0.88 DNI 0.23 0.27 0.68 0.60 0.32 0.55 <0.10 0.88 0.90 DNI 0.19 0.22 0.64 0.64 0.36 0.56 <0.10 0.85

11 0.79 DNI 0.23 0.17 0.71 0.58 0.21 0.60 <0.10 0.44 0.85 DNI 0.17 0.18 0.87 0.60 0.27 0.65 <0.10 0.60 0.75 DNI 0.24 0.17 0.67 0.63 0.26 0.77 <0.10 0.54

12 0.97 DNI 0.22 0.17 0.74 0.58 0.26 0.67 <0.10 0.58 0.88 DNI 0.23 0.17 0.78 0.57 0.27 0.58 <0.10 0. 67 0.85 DNI 0.19 0.20 0.58 0.60 0.26 0.69 <0.10 0.62

14 0.55 DNI 0.21 0.22 0.40 0.53 0.29 0.58 <0.10 0. 52 0.78 DNI 0.18 0.23 0.85 0.55 0.30 0.60 <0.10 0.66

0.72 DNI 0.24 0.20 0.58 0.54 0.19 0.67 <0.10 0.63 Mean 0.83 0.19 0.19 0.67 0.60 0.25 0.66 0. 64 Standard deviat ion 0.07 0.03 0.03 0.10 0.06 0.04 0.06 0.11 Coef f 1 C lent 8.61. 14.3* 14.4% 15.3% 10.8% 16 . 8% 8.9% 17 . ,1 s>. of variation

^ Not included in statistical analysis

Type II rubber coated jute DDD-C-001023 (GSA-FSS) Data in () replaced, ignition suspect. Plugged data point is average of the two good data points.

35
Table 15. Phase II Part A NBS/MMFPA/CRI Interlaboratory Program

Effect of number of specimens on repeatability and

reproducibility

Repeatability Reproducibility

No. specimens % %

1 34 46

3 20 36

10 10 32

36
Table 16. Phase II Part B NBS/MMFPA/CRI Interlaboratory Program data

Two-minute preheat

Average

Code^ Fiber Style Type

Secondary

backing

Pile wt.

,

oz/yd^ Pad*^ CRF,W/cm^

2001 Wool Level loop Velvet Latex 46 yes 0.78 2002 Wool Plush Tufted Jute 42.5 yes 0.58

/2003 Wool Level loop Tufted Jute 42 no 0.76

(2004 Wool Level loop Tufted Jute 42 yes 0.70 2005 Wool Plush Velvet Latex 51.9 yes 0.51

(2006 Polyester Shag Tufted Loktuft 48.5 no 0. 38 (2007 Polyester Shag Tufted Loktuf

48.5 yes <0.1

(2008 Nylon 6,6 Shag Tufted Jute 24 no 0.71 boo9 Nylon 6,6 Shag Tufted Jute 24 yes <0.1

(2010 Nylon 6 Level loop Tufted Jute 20 no DNI

(2011 Nylon 6 Level loop Tufted Jute 20 yes 0. 23

2012 Nylon 6 Level loop Tufted Foam 20 no 0.63

2013 Nylon 6,6 Level loop Woven Sponge 18 no 0. 67

2014 Nylon 6,6 Level loop Woven Sponge - FR 18 no DNI

(2015 Nylon 6 Cut pile Tufted Jute 32 no DNI

(2016 Nylon 6 Cut pile Tufted Jute 32 yes 0.28

2017 Nylon 6 Level loop Tufted Foam - FR 12 no 0.95

2018 Nylon 6 Level loop Tufted Foam 12 no 0.27

2019 Nylon 6 ,

Level loop Tufted Foam - FR 19 no 0. 78

(2020 Nylon 6 Level loop Tufted Jute 28 no 0.40

(2021 Nylon 6 Level loop Tufted Jute 28 yes 0.12 p022 Nylon Multi-level Tufted Jute 20 no DNI b023 Nylon Multi-level Tufted Jute 20 yes <0.

12024 Nylon 6,6 Level loop Tufted Jute 20 no DNI

(2025 Nylon 6 ,

Level loop Tufted Jute 20 yes 0.13

2026 Nylon 6,6 Cut and loop Woven Latex 34.7 no 0.56

i2021 Nylon 6,6 Level loop Tufted Jute 19 no 0.85 b028 Nylon 6,6 Level loop Tufted Jute 19 yes 0.28

2029 Nylon (Sol .

)

Level loop Tufted Foam - FR 24 no 0.88 p030 Nylon 6 Cut pile Axrainster 36 no 0.63

(2031 Nylon 6 Cut pile Axminster 36 yes <0.1

2032 Nylon 6/6 Level loop Tufted Foam 12 no 0.21 p033 Nylon 6,6/6 Shag Tufted Jute 32 no 0.76

(2034 Nylon 6,6/6 Shag Tufted Jute 32 yes 0. 17 p035 Nylon 6 ,

Plush Tufted Jute 45 no DNI

(2036 Nylon 6,6 Plush Tufted Jute 45 yes 0.49

(2037 Polypropylene Level loop Tufted Jute no 0.17 b038 Polypropylene Level loop Tufted Jute yes <0.1

(2039 Acrylic Plush Tufted Jute 46 no 0.20 b04O Acrylic Plush Tufted Jute 46 yes 0.17

2041 Acrylic Level loop Tufted Foam - FR 36 no 0.82

(2042 Acrylic Loop Knitted Latex 60 no 0.50 b043 Acrylic Loop Knitted Latex 60 ' yes 0. 34

(2044 Acrylic Level loop Tufted Jute 32 no 0.75 b045 Acrylic Level loop Tufted Jute 32 yes 0.17 2046 Polyester Level loop Tufted Jute 42 yes <0.1

(2047 Polyester MLRS Tufted Jute 37 no 0. 30 b048 Polyester MLRS Tufted Jute 37 yes <0.1

37
Table 16 (continued)

Average

Secondary Pile wt., . CRF, Code^ Fiber Style Type backing oz/yd^ Pad“ W/cm^

(2049 Polyester (PCP) Level loop Tufted Jute 28 no 0. 36 (2050 Polyester (PCP) Level loop Tufted Jute 28 yes <0.1

(2051 Polypropylene Level loop Tufted Jute 22 no 0.43

(2052 Polypropylene Level loop Tufted Jute 22 yes <0.1 2053 Polypropylene Level loop Tufted Foam 22 no 0.23

(205i Polypropylene Level loop Tufted Jute 16 no 0.32

(2055 Polypropylene Level loop Tufted Jute 16 yes <0.1

2056 Nylon 6 Level loop Tufted Foam 16 no 0.39

2057 Polypropylene Level loop Tufted Foam 16 no 0.28

2058 Polypropylene Level loop Tufted Jute 28 no 0. 26

2059 Acrylic/Nylon Level loop Woven Sponge - FR 40 no 0.64 2060 Acrylic/Nylon Level loop Tufted Foam 42 no 0.82

12061 Acrylic/Mod. Level loop Tufted Jute 32 no 0. 50 (2062 Acrylic/Mod

.

Level loop Tufted Jute 32 yes 0. 21

(2063 Acrylic/Hod

.

Level loop Tufted Jute 42 no 0.68 U064 Acrylic/Mod. Level loop Tufted Jute 42 yes 0. 54

^ Bracketed pairs indicate that the same carpet was tested with and without a pad

.

° Type II rubber coated jute and animal fiber, DDD-C 001023 (GSA-FSS) , Amendment 1.

38
THE

FLOORING

RAOiANT

PANEL

TEST

—I CO

39

Figure

1.

The

Flooring

Radiant

Panel

Test
Fiqure 2

10.2 cm 10.2 cm

1

2

34

5

6

490

490

510

495

500

500

7

8

910

11

12

495

485

470

495

545

525

2.5 cm diam.

Blackbody temperature distribution on non-uniform radiant panel

40
WOOL

CARPETS

ttm

«/> o

t c/*.

•ii— 1.1 cs '“5 UJ

E o

= *S 1.0

0.9

0.2

CARPETS FROM FIRE INCIDENTS

? 1

T

0.1

HARMER HOUSE PIONEER HOTEL

lAPTIST TOWERS

i UHI

Figure 3. Critical radiant flux map

41

PHASE

II

'

PART B

•

MMFPA/CRI/NBS

CARPETS
PHASE

II

PART B

NBS/MMFPA/CRI

INTERLABORATORY

PROGRAM

cso<CD

oeCD

O.

UJO “

h- — UJ UJ

Q. a.

OC DC < < o o

CO C»J 39NVd Nl

42

Figure

4.

Distribution

of

contract

carpet

products

by

critical

flux

ranges
FORM NBS-443

CREV. 4-I1-63J APPENDIX A

U.S. DEPARTMENT OF COMMERCE

NATIONAL BUREAU OF STANDARDS

WASHINGTON. D.C. 20234

NATIONAL BUREAU OF STANDARDS

REPORT OF CALIBRATION

SPECIAL TEST

Detector Responsivity

of

Three Thermal Detectors

Submitted by

Division 490.20

(See Interdivision Work Order No. 490-2220, dated 10/17/74)

I. Material Tested

Three thermal detectors manufactured by MEDTHERM were submitted

for test. The detectors bear serial numbers 124421, 421223, and 124413,

respectively. Each detector was mounted in a water-cooled housing.

Detector #124413 had a CaF2 window attached.

II

Puirpose of Test

The detectors are to be used to determine the incident heat flux

from gas-fired radiant panels in flammability testing chambers. The

purpose of this test is to determine the responsivity of each detector to

an incident radiant flux of approximately 150 mw cm~^.

III. Method of Test

The MEDTHERM detectors were measured against a lamp standard of

total irradiance maintained by the Optical Radiation Section of the

National Bureau of Standards and designated Tl. This standard is a type

DXW 1000-watt, cc-8 tungsten filament, frosted quartz halogen lamp mounted

in a slip cast fused silica parabolic reflector which has been flame

sprayed with AI2 O 3

. [1] The total irradiance of the lamp-reflector

combination has been measured relative to the NBS electrically calibrated

thermopile radiometer, ECR #2. [2] At a distance of 40.0 cm from the

source, the radiant flux is 149.4 mw cm”^ (transfer precision approximately

0.2% [3]; estimated absolute uncertainty, 0.6% [4]).

Each detector was mounted with the geometric center of the blackened

receiver area positioned along, and perpendicular to, the optic axis of the

lamp. The distance from the center of the front surface of the lamp re- flector to the front surface of the receiver area was set to the required

40.0 cm. The detector housing was cooled with tap water at 21.5 +0.5 ®C

with a flow rate of approximately 20 ml/sec.

Test No.: 221.12/1B/74

Date: October 21, 1974

A-1

Page 1 of 5 pages
BEPORT OF CALIBRATION

Special Test

Division 490.20

A movable water-cooled shutter (10.0 cm diameter opening) was placed

at the midpoint of the optic axis between the lamp and the detector. A

black cloth background was placed about 1.5 meters to the rear of the lamp.

No other optics were used.

For a single lamp-detector alignment, a set of 25 measurements were

made with a high impedance digital voltmeter. Each measurement consisted

of reading the detector output with the shutter open and with the shutter

closed. From these measurements the mean value of detector sensitivity and

a standard deviation were calculated.

IV. Results

Detector

Number

Detector Sensitivity

(W cm”^ mv”^)

Precision

(%)

124421 0.271 1.5

421223 0.249 2.5*

124413** 0.234 1.4

*the poorer precision results from the greater inherent noise of this

particular detector

**with CaF2 window in place

V. Remarks

Some degree of caution is necessary in applying these results

directly to other measurements, such as radiant power from a gas-fired

radiant panel. This is especially true in the case of Detector #124413

with the CaF2 window. It should be emphasized that no attempt has been

made to completely characterize the detectors. In general, thermal

detectors are usually fairly linear and spectrally flat over the wavelength region of interest, but no effort has been made to measure the

absolute spectral response, linearity, or long-term stability of the

three MEDTHERM detectors.

In addition, nothing is known about the geometrical properties of

the detector response functions. It should be noted that lamp standard

T1 produces a fairly collimated beam and was calibrated with a detector

whose receiving surface is 0.025 cm^, circular. The test detectors have

receiving areas of about 3 cm^ and are used in an environment that produces

flux from all directions. In using these detectors, measurement errors could arise from either variations in the responsivity function across the

sensitive surface of the detector or from variations in the responsivity

with angle of incidence of the flux.

Test No.: 221.12/1B/74

Date: October 21, 1974 Page 2 of 5 pages

A-2
REPORT OF CALIBRATION

Special Test

Division 49C.20

Enclosed is a typical spectral irradiance curve for the source that

was used in the calibration. Notice especially that this source peaks at

about 900 niti whereas the gas-fired radiant panel apparently peaks in the

2-4 ym range. [5] If one assumes that the detector spectral response is

flat and linear, then the present calibration points would be directly applicable. These assumptions may be approximately correct in the wavelength

region of interest for the two windowless detectors but are definitely

incorrect for the windowed detector.

On comparing the present results with those supplied by MEDTHERM

one finds the following disagreements:

Detector

Niimber

NBS

(W cm”^ mv”^)

MEDTHERM

(W cm“^ mv“^)

Disagreement

(%)

124421 .271 .269 0.7

421223 .249 .258 3.6

124413 .234 .262 12.0

On the basis of the calibration procedures outlined in the MEDTHERM report

[6] a disagreement of 3-5% does not appear to be unreasonable. Furthermore,

if one assumes that the third detector was calibrated without the window as detailed in the MEDTHERM report and the transmission of the CaF2 window is

92% and flat over the regions of interest, then the present calibration

and MEDTHERM 's disagree by only 3%. It should be pointed out, however,

that the actual reasons for the above discrepancies cannot be reliably

inferred without a detailed on-site inspection of MEDTHERM' s calibration

procedures and facilities and a complete characterization of the detectors.

Principle Investigator:

Michael A. Lind

Optical Radiation Section

Heat Division

Enclosures

For the Director

Institute for Basic Standards

Chief, Optical Radiation Section

Heat Division

Test No.; 221.12/1B/74

Date: October 21, 1974 Page 3 of 5 pages

AReferences

[1] W. E. Schneider, A One-Solar-Constant Irradiance Standard,

Appl. Opt. 9_, p. 1410 (June 1970) .

[2] Jon Geist, OPTICAL RADIATION MEASUREMENTS; Fundamental Principles

of Absolute Radiometry and the Philosophy of This NBS Program (1968

to 1971) , NBS Technical Note 594-1 (1972)

.

[3] Jon Geist, New NBS Scale of Irradiance, Appl. Opt. [4], p. 907,

(April 1973), and recent redeterminations, (Jvine 1974).

[4] The Thirty Milliwatt Standards of Irradiance (copy enclosed)

.

[5] J. J. Comeford, The Spectral Distribution of Radiant Energy of a

Gas-Fired Radiant Panel and Some Diffusion Flames, Combustion and

Flame ]^, 125-132 (1972)

.

[6] MEDTHERM in-house report "General Description of Calibration

Procedures for Heat Flux Transducers and Infrared Radiometers."

Page 4 of 5 pages

Test No.: 221.12/1B/74

Date: October 21, 1974

A4
100

90

80

70

60

50

40

30

20

10

0

SPECTRAL IRRADIANCE

TYPICAL 1000 WATT

LAMP-REFLECTOR COMBMATION

WAVELENGTH [fxm]

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APPENDIX B

NBS CENTER FOR FIRE RESEARCH

TOTAL RADIANT FLUX METER, REFERENCE CONVERSION FACTOR

TO:

FROM:

DATE:

SUBMITTING LABORATORY:

TOTAL RADIANT FLUX METER:

Manufacturer

Model No.

Serial No.

Date

REFERENCE CONVERSION FACTOR PROCEDURE

The reference conversion factor (RCF) for the Total Radiant Flux Meter

submitted was determined by comparison with NBS Total Radiant Flux Meter

(TRFM) working standard:

Manufacturer

Model No.

Serial No.

Calibration

Conversion Factor

in the NBS Flooring Radiant Panel Tester. The tester was operated under

the conditions prescribed in the January 7, 1975 Draft Procedure, i.e.

radiant panel temperature about 500°C. With the chamber at equilibrium,

flux profiles were established with the TRFM instrument submitted and the

NBS reference working standard. For each point on the profile, sequential

instrument readouts were obtained within a 4-6 minute interval. This

technique tended to minimize chamber fluctuation effects.

The reference conversion factor for each of the 10 measuring points on the

dummy specimen was calculated by dividing the watts/cm^ determined with

the NBS working standard by the m.v. output of the TRFM submitted, see the

calculation example below:

Calculation Example : NOTE: Data are from the 40 cm measuring point.

Total Radiant Flux (TRF) by NBS-TRFM reference working standard

No. 124421:

B-1
TRF

40 cm. 1.73 m.v. X 0.271 watts = 0.47 watts/cm*"

cm2 m.v.

m.v. output submitting laboratory TRFM = 2.20 m.v.

Reference Conversion Factor at 40 cm. for

submitting laboratory TRFM = 0.47 watts/cm^

2.20 m.v.

RCF

40 cm.

= 0.214 watts

cm2 m.v.

The RCF^q is then averaged with the RCF's from the other nine points

to obtain tne mean RCF. This is the reference conviersion factor used in

establishing the standard flux profile.

The Reference Conversion Factor for TRFM Serial No. is:

RCF = watts

cm2 m.v.

The basic data used in the RCF determination are tabulated in the attached

data logs.

B--2
RADIANT FLUX PROFILE

Date

Black Body Temp. mv. °C

Gas Flow SCFH Air Flow SCFH

Room Temp. °C

Air Press. Gas in. of H_0

Flux Meter

Radiometer No.

Conversion Factor

From Calibration On

Distance

(cm)

MV Watts/cm^ Conversion ' From NBS

5

10

20

30

40

50

60

70

80

90

Average Conversion

No. from NBS

Conversion No.

From Manufacturer

(Manufacturer: ) (Date: )

Signed

B-3
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NBS-114A IREV. 8-78)

U.S. DEPT. OF COMM.

BIBLIOGRAPHIC DATA

SHEET

1. PUBLICATION OR REPORT NO. NBSIR 79-1954

Z, $ Acc^$.1o(i No.

4. TITLE AND SUBTITLE

Development of the Flooring Radiant Panel Test as a Standard Test Method

5. Publication Date March 1980

i€octe

7. AUTHOR(S)

C. Howard Adams and Sanford Davis

8. Performing Organ. Repoit No.

9. PERFORMING ORGANIZATION NAME AND ADDRESS

NATIONAL BUREAU OF STANDARDS

DEPARTMENT OF COMMERCE

WASHINGTON, DC 20234

11. Contract/Grant No.

12. SPONSORING ORGANIZATION NAME AND COMPLETE ADDRESS fSfreer. City, st^te. ZIP)

Sponsored in part by:

The Society of the Plastics Industry

355 Lexington Avenue

New York, New York 10017

13. Type of Report & Period Covered Final

15. SUPPLEMENTARY NOTES

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

16. ABSTRACT (A 200^word or leas factual summary of most significant information. If document includes a significant bibliography or

literature survey, mention it here,) This report deals with the standardization phase of the Flooring Radiant Panel

Test. It describes work done to develop the test as a standard for measuring one

of the major factors contributing to the potential fire hazard of floor covering

systems used in corridors and exitways.

The investigation involved major interlaboratory test programs and focused on:

1) establishing realistic test conditions; 2) defining and minimizing variability;

3) drafting a complete and concise test procedure; and 4) demonstrating the soundness

of the method.

Required flux profile instrumentation calibration procedures were developed and

proven. "Critical Radiant Flux" data obtained on representative floor covering systems

showed the rank ordering of important products such as man-made ahd natural fiber

carpets, vinyl asbestos tile, and hardwood flooring. Acceptable repeatabilities of

about 20% (within-laboratory variability) and reproducibility of about 35% (betweenlaboratory variability) were demonstrated in two major NBS/MMFPA/CRI interlaboratory

carpet system test programs. Fourteen laboratories participated in these full

factorial statistically designed experiments with each laboratory testing eighteen

carpet materials.

17. KEY WORDS ('5XX to twelve entries; alphabetical order; capitalize only the first letter of the first key word unless a proper name;

separated by semicolons)

Critical radiant flux; fire safety; flame spread; flammability; floor coverings;

flooring radiant panel test; test method.

18. AVAILABILITY '3CJ Unlimited

Q] For Official Distribution. Do Not Release to NTIS nOrder From Sup. of Doc., U.S. Government Printing Office, Washington, DC

20402, SD Stock No. SN003-003-

Order From National Technical Information Service (NTIS), Springfield, VA. 22161

19. SECURITY CLASS

(THIS REPORT)

UNCLASSIFIED

20. SECURITY CLASS

(THIS PAGE)

UNCLASSIFIED

21. NO. OF

PRINTED PAGES

.55

22. Price

$7.00

USCOMM-nC
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