NBSIR 75-691

A Characterization and Analysis of NBS

Corridor Fire Experiments in Order to

Evaluate the Behavior and Performance

of Floor Covering Materials

James G. Quintiere

Center for Fire Research

Institute for Applied Technology

National Bureau of Standards

Washington, D. C. 20234

June 1975

Final Report

U.S. DEPARTMENT OF COMMERCE

NATIONAL BUREAU OF STANDARDS
Errata Sheet

for: NBSIR 75-691

entitled: "A Characterization and Analysis of NBS

Corridor Fire Experiments in Order to

Evaluate the Behavior and Performance of

Floor Covering Materials"

by: James G. Quintiere

dated: June 1975

Please make the following correction:

Page 18, Table 4, Column' 9, '

' last line changed from 0.36 to 0.73.

ITSCOMM-NBS-DC
NBSIR 75-691

A CHARACTERIZATION AND ANALYSIS OF NBS

CORRIDOR FIRE EXPERIMENTS IN ORDER TO

EVALUATE THE BEHAVIOR AND PERFORMANCE

OF FLOOR COVERING MATERIALS

James G. Quintiere

Center for Fire Research

Institute for Applied Technology

National Bureau of Standards

Washington. D. C. 20234

June 1975

Final Report

U.S. DEPARTMENT OF COMMERCE. Rogers C.B. Morton. Secretary

NATIONAL BUREAU OF STANDARDS. Richard W. Roberts. Director

CONTENTS

Page

LIST OF FIGURES iv

1. INTRODUCTION AND REVIEW 1

2. INSTRUMENTATION AND SYSTEM DESCRIPTIONS 6

3. QUALITATIVE DESCRIPTION OF FIRE PROPAGATION OVER A

FLOOR COVERING IN THE NBS CORRIDOR 7

4. QUANTITATIVE DESCRIPTION OF FACTORS INFLUENCING FIRE

PROPAGATION 9

4.1. Crib Burning Rate 10

4.2. Flame Spread 10

4.3. Burn Area 11

4.4. Energy Contribution of the Floor Covering Material. 12

4.5. Heating Characteristics of the Floor Coverings. . . 12

4.6. Radiant Heat Flux to the Floor Covering 14

4.7. Ventilation Effects 15

5. SUMMARY AND CONCLUSIONS 17

6. REFERENCES 19

APPENDIX A. RESULTS OF CARPET FIRE EXPERIMENTS IN A CORRIDOR

BY IITRI 21

Appendix A-1. Letter from Bill Segall, Carpet and Rug

Institute 22

Appendix A-2. Excerpt from IITRI Report to CRI 25

Appendix A-3. An Analysis of an IITRI/CRI Floor Covering

Test 32

APPENDIX B. ESTIMATE OF THE ENERGY RELEASE RATE PER UNIT

AREA FOR THE FLOOR COVERING MATERIALS 34

APPENDIX C. COMPLETE RADIATION MODEL FOR DETERMINING FLUX TO

FLOOR ELEMENT BASED UPON WALL AND CEILING SURFACE

TEMPERATURES

.....

37

APPENDIX D. SI CONVERSION UNITS 39

iii
LIST OF FIGURES

Figure A-1. Results from IITRI-CRI corridor carpet burn experiments

(CRI 70-010, carpet No. 28, propane gas room fire of

125,000 Btu/min)

.

Figure 1. NBS corridor facility. (1 ft = 0.3048 m)

Figure 2a. Crib weight loss (experiment 346).

(1 lb = 0.4536 kg)

Figure 2b. Crib weight loss (experiment 347).

(1 lb = 0.4536 kg)

Figure 2c. Crib weight loss (experiment 348).

(1 lb = 0.4536 kg)

Figure 2d. Crib weight loss (experiment 349).

(1 lb = 0.4536 kg)

Figure 3a. Corridor flame spread (experiment 347).

(1 ft = 0.3045 m)

Figure 3b. Corridor flame spread (experiment 348).

( 1 ft = 0.3048 m)

Figure 3c. Corridor flame spread (experiment 349).

(1 ft = 0.3048 m)

Figure 4a. Floor thermocouple locations and path of flame

spread. (1 ft = 0.3048 m)

Figure 4b. Floor flame spread velocity. (1 ft = 0.3048 m)

Figure 5a. Burn and char area with„HCl concentration

(experiment 346). (1 ft = 0.0929 m2)

2 2 Figure 5b. Burn area (experiment 347). (1 ft = 0.0929 m )

2 2 Figure 5c. Burn area (experiment 348). (1 ft = 0.0929 m )

2 2 Figure 5d. Burn area (experiment 349). (1 ft = 0.0929 m )

Figure 6a. Energy release rate (experiment 347). (1 Btu/min = 17.57 W)

Figure 6b. Energy release rate (experiment 348). (1 Btu/min = 17.57 W)

Figure 6c. Energy release rate (experiment 347). (1 Btu/min = 17.57 W)

Figure 7. Combustion products temperature at locations downstream of

fire (experiment 346).

iv
LIST OF FIGURES (cont'd)

Figure 8a. Crib weight loss rate compared with corridor gas temperature

at X = 4 ft, Y = 10 ft, Z = 7 ft 11 in (experiment 346).

(1 Ib/s = 0.4536 kg/s, 1 ft = 0.3048 m, 1 in = 0.054 m)

Figure 8b. Crib weight loss rate, gas temperature (X = 4 f t , Y = 10 f t

,

Z = 7 ft 11 in), and burn area (experiment 347).

(1 Ib/s = 0.4536 kg/s, 1 ft2 = 0.0929 m2, 1 ft = 0.3048 m,

1 in = 0.0254 m)

Figure 8c. Crib weight loss rate, gas temperature (X = 4 f t , Y = 10 f t

,

Z = 7 f t 11 in) , and burn area (experiment 348)

.

(1 Ib/s = 0.4536 kg/s, 1 ft^ = 0.0929 m2, 1 ft = 0.3048 m,

1 in = 0.0254 m)

Figure 8d. Corridor gas temperatures 1 inch (2.54 cm) below the ceiling

at Y = 10 ft (3.05 m) and Y = 20 ft (6.1 m) (experiment 349).

Figure 9a. Floor surface temperature 2 ft (0.61 m) from doorway

(experiment 346).

Figure 9b. Floor surface temperature 0.5 ft (0.15 m) from doorway

(experiment 347).

Figure 9c. Floor surface temperature 0.5 ft (0.15 m) from doorway

(experiment 348)

.

Figure 9d. Floor surface temperature 0.5 ft (0.15 m) from doorway

(experiment 349).

Figure 10a. Corridor floor surface temperature at Y = 6 ft (1.8 m)

(experiment 346)

.

Figure 10b. Corridor floor surface temperature at Y = 6 ft (1.8 m)

(experiment 347)

.

Figure 10c. Corridor floor surface temperature at Y = 6 ft (1.8 m)

(experiment 348)

.

Figure lOd. Corridor floor surface temperautre at Y = 6 ft (1.8 m)

(experiment 349).

Figure 11a. Floor surface temperature distribution (open and black

symbols refer to two independent measurements at the same location) (experiment 346). (1 ft = 0.3048 m)

Figure lib. Floor surface temperature distribution (experiment 347).

(1 ft = 0.3048 m)

V
LIST OF FIGURES (cont'd)

Figure 11c. Floor surface temperature distribution (experiment 348).

(1 ft = 0.3048 m)

Figure lid. Floor surface temperature distribution (experiment 349).

(1 ft = 0.3048 m)

Figure 12. Fraction of radiant energy transmitted through a sapphire

window from a blackbody source.

Figure 13a. Incident radiant heat flux to floor (experiment 346)

(1 ft = 0. 3048 m)

Figure 13b. Incident radiant heat flux to floor (experiment 348).

(1 ft = 0.3048 m)

Figure 13c. Incident radiant heat flux to floor (experiment 349).

(1 ft = 0.3048 m)

Figure 14a. Exit velocities at doorway (experiment 346).

(1 ft/min = 0.00508 m/s)

Figure 14b. Exit velocities at doorway (experiment 348).

. (1 ft/min = 0.00508 m/s)

Figure 14c. Exit and inflow velocities at doorway (experiment 349).

(1 ft/min = 0.00508 m/s)

Figure 15a. Estimated fuel potential burning rate of room fire

(experiment 346). (1 Ib/min = 0.00756 kg/s)

Figure 15b. Estimated fuel potential burning rate of room fire

(experiment 348). (1 Ib/min = 0.00756 kg/s)

Figure 15c. Estimated fuel potential burning rate of room fire

(experiment 349). (1 Ib/min = 0.00756 kg/s)

vi
A CHARACTERIZATION AND ANALYSIS OF NBS CORRIDOR FIRE EXPERIMENTS

IN ORDER TO EVALUATE THE BEHAVIOR AND PERFORMANCE

OF FLOOR COVERING MATERIALS

James G. Quint iere

Data is presented for four fire experiments which examine

the fire propagation from a room fire to a floor covering

material in a corridor. The four floor covering materials

include a nylon and an olefin carpet, vinyl sheet, and red oak

flooring. Limited flame spread occurred for the vinyl sheet

material; however, the three other materials involved full fire

propagation in the corridor. The data are analyzed to examine

the factors influencing fire propagation. Included in this

analysis is the rate of energy contribution from the room fire

and floor covering material, the rate of flame spread, heat

transfer to the floor covering, and flow interactions between

the room and corridor. A review of previous related experiments

is also presented.

Key words: Corridor fire spread; energy release rate; fire

induced flow; flame propagation; flashover; floor coverings;

radiant heat flux.

1. INTRODUCTION AND REVIEW

A need exists to develop a laboratory test method which can measure

the flammability performance of floor covering materials. Within the

limits of our present understanding, this method must be capable of measuring the relevant parameters of the potential hazard associated with

building fires. One special aspect is the spread of fires through corridors in which the floor material is the primary combustible lining. Such

an arrangement has been the focus of investigation in the NBS corridor fire

experiments. From the results of these experiments and analysis thereof, we wish to determine quantitatively the role of floor covering materials

with regard to fire propagation and energy release rate. In addition, we

seek to characterize the interaction between the room fire and the spread

of fire to the corridor. The potential hazard associated with smoke development is not examined in this study.

The results of NBS corridor fire experiments involving a number of

floor covering materials have been presented by Fung, Suchomel, and Oglesby

[l]-*-. They report: (1) the primary hazard is rapid flame spread from the

burn room down the length of the corridor; (2) most of the energy released

in the room is transferred into the corridor by radiation and convection;

(3) radiant preheating of the floor covering prior to rapid flame spread

is the dominant mode of heat transfer; (4) after flashover the energy

^lumbers in brackets correspond with the literature references listed at

the end of this paper.

1
release rate of the floor covering can exceed 100,000 Btu/min. In their

report, floor covering materials are ranked in performance by calculating

the time integral of energy input rate to the corridor up to the onset of

full corridor involvement. Also presented in their report is a flame

spread analysis based on radiant preheating of the floor covering.

Based on the data from these experiments a summary of conditions and

results has been tabulated in tables la and lb. Omitted information is

either inaccessible or not available. The weight loss behavior, for one

of the four ignited cribs, was represented by two parameters - time to

achieve steady burning and burning rate. Since the burning rate is generally unsteady, these parameters must be selected with some degree of arbitrariness. In these experiments it seemed appropriate to select the time

factor as the time at which 5% of the crib was consumed, t^.^. The average

burning rate was then chosen as the change in crib mass between t.^, and

flashover occurred divided by the time between these events. Flashover

time was taken at the instant of rapid flame spread in the corridor. It was based on a rapid increase in the temperature by the thermocouples

located on the surface of the floor covering material. Flashover is

defined in this paper as a sudden rise in the gas temperature followed by

rapid flame spread. ,.

The character of the NBS corridor fires has been either rapid flame

spread along the length of the corridor space or an unsustained flame

spread several feet beyond the burn room doorway. The former characterization has been the prevailing one for this series of experiments. Two

situations occurred which do not fit clearly into either of these two

modes of characterization. In test 336 (vinyl asbestos tile) two local

flashovers occurred. The first occurred at 520 seconds and flame spread

on the floor from 5 to 10 feet in 9 seconds; the second occurred at 1,020

seconds with final flame spread to 15 or 20 feet. The fire was extinguished

at 1,080 seconds. Finally, in test 337, a flashover occurred at 420 seconds,

however, subsequent flame spread did not go beyond 15 feet.

Because flashover was a prevalent mode of behavior in these experiments,

flashover time is an obvious criterion for ranking material performance.

Alternative criteria might be an adjusted flashover time (flashover time

minus tea,), or the energy criterion used in reference [1]. Time to flash- over is probably the most accurately determined quantity of these criteria.

It was compared to the results of several standard and proposed flame spread

test methods. The results were presented and discussed by Quintiere and

Huggett [2]. It is shown in that report that good correlation resulted

between any flame spread test method and these corridor fire experiments.

Corridor experiments involving other carpet materials were performed

by Illinois Institute of Technology Research Institute (IITRI) under a slightly different arrangement. Although the severity of their room fires was greater than the NBS fires, no flashover or sustained propagation

Conversion factors from units used in this report to SI units are given

in appendix D.

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occurred in any of the IITRI experiments for carpets which passed the pill

test.-^ A summary of the IITRI work is contained in appendix A. Several

reasons can be considered to explain the differences in corridor fire

behavior between the NBS and IITRI experiments. First, the nature of

materials tested could have differed considerably. Based on the description of the carpets tested by IITRI (all passed the pill test) , no obvious

differences can be attributed to carpets. However, IITRI does report that

an earlier carpet corridor test with a carpet which failed the pill test

did lead to a flashover behavior similar to that seen in the NBS experiments. Second, IITRI used propane gas as a primary fuel source with an energy equivalent rate of 125,000 Btu/min while NBS used wood cribs at a nominal energy release rate of 80,000 Btu/min. A 3 ft x 8 ft section of

floor covering material in the NBS burn room also contributed to the

energy release into the corridor. However, it was estimated that the

total rate of energy supply to the corridor was higher for the IITRI

experiments. Third, the thermal characteristics of corridor construction

material differed to some extent. NBS primarily used 5/8 inch gypsum board

on steel studs backed by glass-fiber insulation for corridor walls and

ceiling with a subfloor of 1/4 inch asbestos cement board (130 Ib/ft"^) over brick and sand. IITRI used a fire-brick type construction for its

walls which was said to have been selected to match the thermal properties

of a plaster wall. The floor was concrete and the ceiling was asbestos

board. Results from IITRI corridor experiments shown in appendix A indicate steadily increasing gas exhaust temperatures at the corridor midlocation whereas the NBS corridor gas temperatures approach steady state in

6 to 10 minutes when not influenced by the floor covering fire. Also, the

floor covering fire did not appear to have contributed to the exhaust gas

temperature levels of the IITRI work. Either the carpet fires did not

contribute a significant energy release rate, or the wall and ceiling

construction of the IITRI corridor absorbed a significant quantity of heat

and had a long time response. The steadily increasing gas temperatures

tend to support this conclusion. Unfortunately, no wall or ceiling surface temperature data from the IITRI work is available to us. Fourth, room

and corridor configuration differed between the NBS and IITRI tests. The

IITRI corridor is 55 ft long, 6 ft wide, and 8 ft high. The corridor

"window" was the full corridor cross section, and the doorway to the burn

room was 6 ft wide and approximately 6-7 ft high. The burn room was 10 ft

X 15 ft x 8 ft high. It appears that potentially more induced airflow

was available to the corridor and room in the IITRI fires than the NBS fire

experiments. For the case of no combustible corridor linings IITRI reports

[3] an air inflow rate of 180 Ib/min for a propane room fire of 125,000

Btu/min. Only 98 Ib/min of air is required for complete stoichiometric

combustion of this propane flow. Although airflow measurements are not

available for their carpet experiments, it appears that they have a sufficient air supply to prevent fuel rich conditions from developing. It will

later be shown that changes in flow conditions during the NBS fires lead to

insufficient air in the burn room for complete combustion.

DOC FF 1-70, Carpet and Rugs (Pill Test) Standard for the Surface Flammability of Carpets and Rugs.

5
The effect of ventilation, i.e. induced airflow on fire propagation in

corridors (and rooms), can be significant. Corridor experiments [4] in the

second floor of an old school building with a corridor of 11 ft width, 13

ft height, and 72 ft length demonstrated the effect of airflow on fire

spread. Two half-open windows (approximate opening 3 ft x 5 ft) provided

ventilation; and two 250 lb wood cribs provided a burning rate of 14 to 20

Ib/min after 11 minutes. In all three experiments investigating flame

spread on wall materials (the floor was hard wood with the finish worn

off), flashover occurred in 6 to 7 minutes and was characterized as rapid

combustion of the hot pyrolysis products encountering sufficient air; yet,

surface flame spread along the wall lining material was not extensive

before flashover. Crib flaming was momentarily reduced following flashover, but then flaming was reestablished (for the wall lining as well as the cribs). Thus, the cribs appeared to have generated a steady fuel

supply with insufficient airflow, and when the excess fuel in the exhaust

products mixed with a sufficient amount of incoming air, gas phase propagation occurred.

Other relevant corridor fire experiments are those conducted by

McGuire [5]. A full-scale test in a corridor 6 ft wide, 8 ft high, and 63

ft long with concrete block walls, an asbestos board ceiling and a cellulose triacetate carpet on a concrete subfloor resulted in a flame propagation of 40 feet. The carpet had a rating of 435 by ASTM E 162. The

exhaust end of the corridor was closed at the lower half and smaller vents

existed along the corridor walls, top and bottom of the back wall, and in

the burn room. The burn room doorway was 6 ft high and 3 ft 4 in wide.

The fuel source was primarily nine 4 ft x 8 ft fiber insulation boards

stacked vertically in the room. This study concluded that floor coverings

having an ASTM E 162 index of 220 and less made little contribution to

indefinite fire propagation in these particular experiments. Corresponding

threshold values were 130 for ceiling linings and 35 for wall linings.

The present report seeks to present the results of four NBS corridor

fire experiments not previously presented. Its objective is to examine the

role played by the floor covering material in these corridor fire experiments. The use of high speed data acquisition systems in these four

experiments permitted a detailed examination of a considerable quantity of

data. These experiments will now be described.

2. INSTRUMENTATION AND SYSTEM DESCRIPTIONS

The dimensions of corridor-room system are listed as follows:

Corridor length = 30 ft (9.1 m)

Corridor width = 8 ft (2.4 m)

Corridor height = 8 ft (2.4 m)

Room floor = 7 ft 9 in x 8 ft 5 in (2.4 x 2.6 m)

Room height =9 ft 4 in (2.8 m)

Doorway = 6 ft 6 in x 2 ft 6 in (2.0 m x 0.76 m)

Exhaust window = 3 ft 4 in x 5 ft 9 in (1.0 m x 1.8 m)

Room vents (2) = 7 in x 14 in (0.18 m x 0.36 m)

6
Data from as many as 60 thermocouples measuring gas and surface

temperatures, five radiometers measuring corridor wall and floor incident

radiant flux, assorted gas monitoring equipment, and pitot tubes at the

window and doorway (measuring outflow at the top and inflow at the bottom)

were recorded on a paper tape high speed data acquisition system at a scan

rate of 9 channels per second. Up to twenty thermocouples monitoring floor

flame spread and some gas monitoring equipment were recorded on a magnetic

tape data system at a scan rate of 40 channels per second. The flame

spread thermocouples were distributed to enable a record of the extent of area burning. The location of these thermocouples is shown in figure 4a.

During tests 346-349 an effort was made to improve the quality of

motion pictures taken of the fire development. In test 348, the view

window facing the doorway was lowered to about 2 feet from the floor and

heated with a hot air jet. This eliminated obscuration due to condensation

of smoke particulates and permitted filming up to flashover. This was repeated in test 349 with an additional view window at the exhaust window

at the end of the corridor. A time lapse camera set on automatic operation

recorded events continuously at one frame per second up to 20 seconds

before flashover. A third camera shot through the exhaust window as in

previous tests. In these tests, observations on flame spread behavior were

recorded.

In experiments (346-349), to be examined here, the following floor

covering materials were used: vinyl sheet flooring, nylon and olefin

carpets, and wood flooring. A description of these materials is given in

table 2.

3. QUALITATIVE DESCRIPTION OF FIRE PROPAGATION

OVER A FLOOR COVERING IN THE NBS CORRIDOR

A qualitative description of fire propagation over a floor covering

material in the NBS corridor will be presented. The more prevailing mode

of propagation involving flashover followed by rapid flame spread will be

considered. This description will be based upon visual observations

recorded during the test and from the analysis of the test films. A

schematic of the facility is shown in figure 1. Thus, a subjective interpretation of the fire behavior can be developed. A quantitative interpretation will follow in the next section. A description of test 349 — red

oak flooring — will be presented.

0-27 s Four wood cribs are ignited by pans containing heptane.

60 s Smoke begins to exhaust from the burn room into corridor.

170 s Smoke is darkening in the upper 1/3 to 1/2 of the corridor.

Flames flicker to 3 ft out of the doorway.

220 s Vapor evolving from floor in burn room and crib fires

appear to be fully developed.

240 s Smoke is darker and fills the upper half of corridor;

diffusing and settling to lower corridor half-space.

245 s Ignition on the wood floor in burn room followed by

rapid flame spread over this section of flooring.

7
Table 2. Description of Flooring Materials

Test No. Floor Covering Description

Heat of

o , .a Combustion

(cal/g)

Mass per

Unit Area

(g/cm^)

346 Vinyl Sheet

(R-4g)

0.05 inch vinyl

chips bonded to a 0.04 inch organic

felt backing.

Sheet was bonded

to an asbestos

cement board subfloor.

2,970 0.315

347 Olefin Carpet

(0-lg)

Level loop olefin

fiber with a polypropylene-j ute

backing. Carpet was bonded to an asbestos cement board

subf loor.

4,960 0.185

348 Nylon Carpet

(N-3/u)

Level loop nylon

with a jute-jute

backing. Carpet

laid on hair-jute

pad over asbestos

cement board subfloor.

4,590 0.244

349 Red Oak

Flooring

(RO)

3/4 inch tongue

and groove red oak

floor. Flooring

mounted on pl5wood

subf loor

.

4,460 1.27

igher heating value determined by the oxygen bomb method.

Conversion to SI units: 1 in = 0.0254 m

1 cal/g = 4,184 J/kg

2 2 1 g/cm = 10 kg/m

8
270 s Entire contents of the burn room are flaming; fire on floor Is holding at the doorway.

275 s Grey smoke Is obscurrlng all but lights in corridor.

400 s Floor fire has spread slowly into corridor about 1-1/2 ft

out of the doorway. Flames on the floor are leaning back

toward the burn room due to the induced air current.

450 s Visibility is increasing in lower half-space. Some

burning and charring of paper is occuring on the gypsum

board of the rear wall adjacent to doorway.

487 s Flame is beginning to spread along floor molding at base

of rear wall toward the side wall.

~490 s Flame has spread about 3 ft out of the doorway and about

1 ft to the right of the doorway. A strong effect of

induced airflow is apparent on the leading edge of flame

front.

490 s Apparent "fire whirl" or elongated flame occurs above the

floor fire. Some flaming is visible along the base

molding to left of the main flame area,

527 s Smoke is becoming black and dense over the upper corridor

half-space.

548 s Flame has spread on floor 4 ft out of the doorway and

"fire whirls" are beginning to appear often with a duration of 1 to 3 seconds.

582 s Flame has spread to 6 ft out of the doorway and a flame

plume is developing over the central area reaching 3 ft

in height.

600 s An increase in flame height is followed by darkening of

the corridor space.

635 s Flashover begins as the flames fill the rear of the

corridor space.

658 s Dense black smoke is exhausting from window.

713 s Flame propagation is nearing the exhaust window.

717 s Flames emerge from the window.

The fire was extinguished at 750 s and charring damage due to surface

flame spread over the floor was extensive. Rapid fire propagation through

the corridor appeared as a sheet of flames filling the corridor space

behind it and flowing dense black smoke ahead of it. The average rate of

propagation was about 20 ft/min. When rapid flame spread began it was preceded by a localized flashover of the corridor space near the doorway.

By appearance, this localized flashover took the form of the fire character

changing from a creeping surface flame spread to a volume of flames filling

the corridor space. The transition occurred in several seconds.

4. QUANTITATIVE DESCRIPTION OF FACTORS INFLUENCING FIRE PROPAGATION

The thermal measurements taken in tests No. 346-349 will be reviewed

and analyzed. These measurements permit the estimation of flame spread

rate, energy release rate, and incident radiation to the floor. In addition, they help to evaluate instrumentation performance. It should be

9
pointed out that a complete set of data for test 347 could not be developed

because of problems with the paper tape output.

4.1. Crib Burning Rate

One of four identical wood cribs was placed on a load cell platform

and its weight loss was recorded. This crib was located in the center of

the burn room floor with the other cribs located in each of the three corners of the room. The load cell response along with rate of weight loss

is shown in figures 2a, b, c, and d for experiments 346, 347, 348, and 349,

respectively. In general, the load cell response is smooth, however,

initial crib weight is not correctly indicated and sudden increases in

weight are sometimes indicated. The first effect is probably due to improper setting of the initial tare weight, while the second effect may be due

to a temperature increase of the load cell. More efficient cooling of the

load cell would eliminate this problem. The relative weight loss changes

are expected to be accurate and a smooth curve through the data points was

used to determine the rate of weight loss. After 2 to 3 lbs of weight

loss, the rate of weight loss tends to be fairly constant up to flashover

or beyond. The maximum energy release rate of the four cribs is calculated

based on the steady weight loss rate of one crib and a nominal heat of

combustion of wood equal to 7,200 Btu/lb (4,000 cal/g) . This yields

maximum energy release rates of 70,000 to 82,000 Btu/mln. Variations in

the steady burning rate of the wood cribs indicate the extent of variation

in reproducibility for wood crib fires. If the unmonitored wood cribs are unaffected by location, they may be expected to burn as the crib monitored

by the load cell. Thus, it is reasonable to expect that all experiments

had the same level of energy release rate from the crib fires (approximately 75,000 Btu/mln). Before steady burning was attained it is not

obvious from crib weight loss data whether the fire buildup rate was the same from four cribs for each experiment. The fire buildup period for the

monitored crib varied from 100 to 400 seconds for these experiments. The reason for this time variation is not known.

4.2. Flame Spread

Flame spread over the floor covering material generally followed a path out of the burn room doorway then along the corridor. Initially, the

flame progress from the doorway to the corridor centerline was slow; however, if flashover occurred a rapid flame spread would follow. The rate of

flame spread was determined by the thermocouples placed in contact with the

floor covering surface. As the flame reached the thermocouple, the surface,

especially if it was a carpet, regressed away from the thermocouple. The

thermocouple then measured a gas phase temperature between the surface and

flame temperatures. In general, a rapid rise in temperature (e.g. 20 °C/s) or a temperature greater than 40 0°C was sufficient to indicate flaming at

the thermocouple position.

10
Surface flame spread results are shown in figures 3a, b, and c for

experiments 347, 348, and 349, respectively. On the curves, the horizontal

line indicates the spread out of the doorway and at Y = 1.5 ft. Although a solid line indicates an average flame spread down the corridor, the initial

spread rate is extremely rapid for the first 10 ft. Moreover, in test 347 an advancing sheet of flames filling the corridor crosssection appears to

have led the surface flame spread as indicated by the thermocouples.

The rate of flame spread was computed based on a path of travel as shown in figure 4a. The results are shown in figure 4b. In all cases involving flashover the spread rate increased by a factor of 10 or more following flashover.

4.3. Burn Area

The area of the floor covering involved in burning gives an indication

of the energy contribution of the floor covering. This was monitored

during an experiment by 18 to 20 surface thermocouples along the floor.

Each thermocouple was associated with an area with four thermocouples over

the 24 ft^ section of floor covering in the burn room and the remaining

thermocouples distributed over increasing area sectors as distance

increased from the doorway. Although ignition was easily discerned from

thermocouple response, extinction was not as obvious. In most cases burning was continuous following ignition until water was applied to

extinguish the fire. However, a steadily decreasing temperature response

(following ignition) was adopted as a criterion for extinction of flaming.

The burning area curves are shown in figures 5a, b, c, and d. In

figure 5a, the results for vinyl sheet flooring indicate a relatively small

area burned. Also, in this figure the utility of monitoring the area affected by the fire is demonstrated in interpreting other data. A temperature of 200 °C was used to indicate thermal decomposition of the vinyl

sheet flooring. (Polyvinyl chloride decomposes between 200-300 °C)[6].

HCl measurements [7] associated with the decomposition of PVC are seen to

follow a trend similar to the extent of "charring". In^fact, from 600 to

1,200 seconds the HCl production rate is 10+1 ppm/ft of flooring which

is above 200 °C. Observations of the floor covering after test 346 Indi9 2 cated a burned area of 5 ff^ in the corridor (in addition to the 24 ft

in the burn room) and a continuous char area of 20 ft^ along with patches

of char zones over another 20 ft^. These observations are consistent with

the areas determined by thermocouple analysis.

The results for tests 347 through 349 all involved flashover. In each

case flashover occurred when approximately 15 ft^ of corridor floor covering was burning. The nylon carpet in 348 did not burn the full corridor

length although flames emerged from the exhaust window. Carpet samples

taken from Y = 18 ft and Y = 21 ft indicated melting, but no loss of

weight. The thermocouple record of the nylon carpet surface at Y = 21 ft

indicated that its temperature reached 220 °C corresponding to its melt

temperature [7] at 588 seconds. Since this fire was extinguished at 600

seconds it appears that not much mass loss would occur in 12 seconds.

11
Again, the thermocouple Interpretation of the burning and phase change

behavior of the floor covering materials appears to be reasonably in

agreement with other observations and data.

4.4. Energy Contribution of the Floor Covering Material

In evaluating the flammability hazard of floor covering materials, the

significance of the energy release by that material must be considered. An

attempt to estimate the energy release rate of the floor covering materials

in experiments 346-349 was made. By estimating the energy release rate per

unit surface area E^, and knowing the area burning, A^, the energy release

rate could be determined. The energy release rate per unit area was estimated by using heats of combustion determined by an oxygen bomb calorimeter,

mass measurements of the floor coverings, and duration of burning. This

yields a maximum heat release rate which is consistent with the crib estimates. The details are presented in appendix B.

Figures 6a, b, and c indicate energy release rates for floor covering

and crib combustion. Experiment 346 is not displayed since the floor

covering contributed a small amount of energy, i.e. a maximum release rate

of 7,000 Btu/min. Although the energy release rate by the floor covering

before flashover is about 15% of the crib release in experiment 347, it is

about 30% in experiments 348 and 349. Hence, the energy release by the

floor covering can be a contributing factor in promoting flashover.

In order to verify the energy release rate estimates made from burn

area analysis, a qualitative indicator can be used. In reviewing data it

has been observed that the thermocouple measuring corridor ceiling gas

temperature responds very quickly to burning rate changes. Figure 7 displays ceiling gas temperature response for experiment 346 in which the

predominant energy contribution was from the burning cribs. The temperature levels in the burn room and doorway indicate flaming after 400 seconds.

Outside this combustion zone the temperature drops significantly (Y = 10

ft, 20 ft, and 30 ft), and is a more direct indicator of energy rate

released by combustion. Hence, the increase in gas temperature at Y = 10

ft can be used as a qualitative indicator of energy input rate up to

flashover. These results are displayed in figures 8a, b, c, and d for

experiments 346, 347, 348, and 349, respectively. Figure 8a indicates a maximum AT at Y = 10 ft of about 380 °C which can be associated with the

maximum crib energy release rate. Before flashover and during periods

when the floor covering was burning AT at Y = 10 ft is about 420 °C for

experiment 347, 550 °C for experiment 348, and 450 °C for experiment 349.

Except for experiment 348, these values are generally in qualitative

agreement with floor covering energy release rate estimates.

4.5. Heating Characteristics of the Floor Coverings

The rate of heating of the floor covering materials before ignition

and flashover is dependent on the radiant flux originated from the flames

emerging from the doorway and the heated walls and ceiling. For the

12
region near the doorway the heating rate is high and ignition occurs

quickly. This is seen in figures 9a, b, c, and d where floor surface

temperature is plotted for each experiment. The time at the initial

temperature rise is reflective of the variations in ignition characteristics of the wood cribs. Locations down from the doorway (Y = 6 ft or 8 ft)

display a heating characteristic indicative of most of the floor covering

in the corridor. These curves are shown in figures 10a, b, c, and d. To serve as a guide in assessing the phase transitions which may occur for the

floor coverings some transition temperatures are listed in table 3 for the

materials in these experiments. It appears that the distinct temperature

plateaus in figures I'Ob and 10c can be interpreted as melting transitions

for polypropylene and nylon, respectively. In addition it will be seen

that these periods of no temperature rise can be associated with the

periods of almost constant heat flux. Hence, these plateaus could be

interpreted as periods of temporary equilibrium as well.

Table 3. Transition Temperatures

Material Polymer Melt Temperature

(°C)

Decomposition Temp.

(°C)

Vinyl Sheet

Olefin Carpet

Nylon Carpet

Red Oak

Flooring i

PVC

Polypropylene

Nylon

Wood

165^

216-260^

a 200-300

328-410^

316^

1

! 200-320^ i Source: Reference [6]

Source: Reference [8]

Source: Reference [9]

The temperature distribution along the floor covering surface of the

corridor is depicted in figures 11a, b, c, and d. Figure 11a indicates

the highest temperatures attained by the vinyl sheet flooring. In experiment 347 only a small change in heating is seen to occur preceding flashover, i.e. between 500 to 800 seconds. At most, about the first ten feet

of the polypropylene carpet could have been melting. A similar heating

behavior is seen for the nylon carpet in experiment 348. The red oak

floor in experiment 349 appears to have been on the verge of pyrolyzing

over the first six feet of corridor just before flashover. Although a significant portion of the floor covering materials in each of these

experiments has received a severe exposure to heat, it does not appear

that this alone is the cause of flashover. The carpet temperatures were

almost steady for at least 5 minutes before flashover in experiment 347

and yet the flame is spreading slowly during this period. Then, suddenly

flashover occurred near the doorway corridor region without any advance

warning based on the floor temperature levels. Based on the thermocouple

response there appears to be no sudden release of pyrolysis products from

13
the nonf laming floor covering preceding flashover. Thus, this flashover

phenomenon does not appear to be caused by rapid rise of a large section

of floor covering to its "ignition temperature" or a release of pyrolysis

products from large sections of floor covering which is ignited as a cloud

of combustible gas. In fact, even after flashover in experiment 347, the

nonburning region of floor covering has not reached its decomposition

temperature. However, it is expected that this preheating before flash- over does enhance flame spread over the flooring material and a small

increase in heat transfer to the floor could trigger a rapid flame spread.

4.6. Radiant Heat Flux to the Floor Covering

Although four radiometers facing upwards were positioned along the

corridor floor to measure incident radiant flux continuously, they had some deficiencies which precluded an accurate quantitative interpretation

of these data. Basically, the use of a sapphire window in the radiometers

excluded long wavelength radiation (above about 5 pm) from being transmitted to the sensor element of the instrument » A theoretical estimate

along with some experimental corroboration shown in figure 12 indicates the

magnitude of the radiation transmitted by sapphire for a blackbody source. During the experiments the radiometers (and the floor coverings) not only

see the heated surfaces which respond as grey bodies, but also hot combustion

products which include particulate and gaseous emittors of radiant energy.

The gaseous combustion products emit most radiant energy below 5 pm which

would be completely recorded by the radiometer. Smoke particles in the

products emit continuously as a function of wavelength with a blackbody

distribution. The smoke particles had a higher temperature than the ceiling

or walls in these experiments, so it follows from figure 12 that the fraction of emitted energy recorded by the radiometers would be greater for

smoke (and flames) than for the ceiling and walls. Hence, the radiometers

would be more responsive to radiation from the hot products than from

radiation from the heated ceiling and walls.

A calculation scheme was developed to estimate the incident radiative

flux along the corridor floor based upon the heated walls and ceiling. The

surfaces were assumed to be blackbodies. The ceiling, upper half of the

side walls, and rear wall were included. The source temperature distribution was based on the ceiling temperature measurements and was assumed to

be a function of position Y (and time) only. The details of this calculation are described in appendix C. The results provide at least a qualitative measure of the distribution of incident heat flux to the floor

covering materials before flashover. Also, they provide some insight in

assessing the source of radiation when these results are compared with the

radiometer measurements. In general, the radiometer measured flux was

lower than the calculated flux. However when black smoke passed along the

corridor (e.g. due to ignition of the flooring in the burn room), then the

radiometer reading exceeded the calculated flux value. It was estimated

that the flux contribution from high temperature soot particles could be

significant (i.e. approximately 3 watts/cm^).

14
Some of the calculated heat flux results along with measured values

are presented in figures 13a, b, and c. No results are available for

experiment 347. Preceding flashover, the highest radiant heat flux to

the floor occurred in experiment 348 followed by 349 and then 346. This

is consistent with the energy release rate implied by corridor gas temperature results for the flooring materials. Thus, an increase in smoke and

energy release of the materials may have caused a corresponding increase

in radiant heat flux to the floor. If radiant flux to the floor originated from the heated walls and ceilings, the measured results should be

below the calculated results from ceiling temperature data due to the error caused by the sapphire window. This is the case in figures 13a and

13c. However, in experiment 348 (fig. 13b) the measured incident radiant

flux, before flashover, actually increased, then decreased. The increase

exceeded the calculated value and was probably due to radiation from smoke.

A more detailed analysis of radiation from combustion products in these

experiments is considered by Bromberg and Quintiere [10]

.

4.7. Ventilation Effects

It has been suggested that ventilation effects are the source of the

differences between the IITRI carpet experiments and the NBS experiments.

The data from the pitot tubes at the burn room doorway and corridor exhaust

window were examined to explore this effect. Initially, the data from the

pitot tubes aligned to measure the air inflow through the corridor window

and into the burn room were examined. The quality of these data were poor

or the response on the pressure transducers was too small to yield an accurate velocity measurement. The data from the pitot tubes which monitored the exhaust products were then examined. While the corridor exit

window exhaust flow tended, generally, to increase or remain stationary

during the experiment, the exhaust products from the burn room tended to

decrease in velocity before flashover. This implies a decrease in the airflow to the burn room to support crib combustion. The burn room exhaust

flow data was then analyzed to determine the magnitude of the induced flow

rate of air.

The velocities measured by the doorway exhaust pitot tubes are shown

for experiments 346, 348, and 349 in figures 14a, b, and c, respectively.

No data are available for experiment 347. In experiment 346 no flashover

occurred and the velocity data tended to follow the crib burning rate

response. However, in experiments 348 and 349 there was a steady drop in

the exhaust velocities up to 2 minutes before flashover. In fact the pitot

tubes gave a negative pressure drop reading after flashover. This suggests

that reverse flow or large cross flow eddies occurred in the doorway. This

reduction of exhaust velocities at the doorway has been recorded in previous experiments. In particular, in an earlier experiment (336), which

did not have a sustained flame spread, a localized flashover occurred

preceded by a reduction in exhaust velocity. Subsequently, the crib

burning rate dropped by 1/2, but no rapid flame spread developed.

15
By using these velocity data an average exhaust mass flow rate was estimated based on air properties as the exhaust fluid. Knowing the weight

loss rate of the cribs the inflow of air through the doorway was found by

M

air

in

= (PVA) out

- 4 M

single

crib

(2)

This not only includes the airflow in through the doorway, but also the air

inflow through the two vents in the burn room. In experiment 346 this

inlet vent flow was monitored and a mass inflow rate of approximately 20

Ib/min was estimated during fully developed room fire conditions. Excluded

in the above equation is the mass production rate of flooring material

burning in the burn room. If a fuel to air mass ratio (y, ) of 0.25 is fa

used for the complete stoichiometric combustion of wood (fuel-air ratio

can vary from 0.22 to 0.27 for wood) [11], then the potential burning rate

can be determined. However, inefficient combustion is likely and not all

of the air may be used for combustion in the burn room. Thus, 75% of the

air (by mass) was assumed to be consumed, which corresponds to a volume 0^

concentration of about 5% - typical of measured 0^ concentration in the

exhaust products before flashover. The results of these calculations are shown in figures 15a, b, and c. The "potential fuel consumption" indicates

the rate at which wood can be burned in the burn room based on available

airflow. Based on a point velocity measurement at the vent, it was estimated that about half of the required airflow to support crib combustion

enters through the vents. It is significant that more than sufficient airflow occurs in experiment 346 where no flashover occurred; yet, in experiments 348 and 349 airflow became insufficient before or at flashover. This

implies that fuel gases can be released from the burn room before they are burned. Whether this is the cause of the flashover phenomenon that occurs

in these experiments is not completely known; however, these calculations

present strong evidence that ventilation effects are significant before

flashover.

The cause of the flow decrease to the burn room can only be speculated on. Flow into the corridor system is basically determined by the

temperature difference between the corridor-room system and the outside

air. Flow between the room and corridor will also be determined by temperature differences between the two compartments. It appears that the extent

of flame spread on the corridor floor also can have a significant effect

on the airflow. It may be that once a critical floor area is burning in

the corridor ahead of the doorway, then the incoming air flow is heated

sufficiently to cause it to rise and flow back out of the corridor rather

than into the burn room. Although this' depletion of air would affect the

burning rate of the wood cribs, this effect would lag the reduction in air

flow. This follows because once the cribs build up to a fully developed

burning stage the heat transfer between the sticks maintain the gasification

of the wood. Reducing the airflow would shut off the release of energy

during oxidation within the crib vertical shafts; however, glowing surfaces

16
of the sticks would maintain high heat transfer to continue the gasification

process for some time. Thus, the cribs would continue to supply fuel gases

for at least a short time following loss of sufficient airflow. This sudden

release of combustible gas to the rear of the corridor with heated air now

mixing with it would result in combustion throughout the space. This is a plausible explanation of the flashover phenomenon that does occur. This

would result in increased heat transfer to the corridor which can lead

to the rapid flame spread phenomenon that most often follows flashover.

- 5. SUMMARY AND CONCLUSIONS

Four corridor fire experiments in the NBS facility have been reviewed.

Each experiment investigated flame spread on a different floor covering

material. Although each of these materials may be associated with a class

of floor covering materials it would be improper to extend the results of

these experiments to other materials of similar type. Indeed, the results

of the NBS corridor experiments differ markedly from those of IITRI in

terms of propensity to flashover. Yet, carpet materials were tested in

both corridor facilities. Moreover, the differences between experimental

results in these facilities suggest that the system variables are factors

controlling flashover as well as the properties of the particular floor

covering material tested. Thus, the initial constraints imposed by the

experimental design can represent a subtle ingredient which can contribute

significantly to the development of flashover.

On the other hand, the four experiments reviewed in this report should

be representative of the preceding similar experiments conducted in this

series (table 1) . A summary of results for these four tests is given in

table 4. Relative differences caused by the combustion behavior of the

four materials can be seen. It was pointed out that the initial flame

spread on to the corridor floor was promoted by the radiant heat received

by the floor. Radiant heat flux results near the room doorway are shown

in the table and compared to "critical" incident heat flux values necessary

to sustain flame spread. (These "critical values" were determined in the

apparatus described by Hartzel [12].) In experiments 348, 349, (and

probably 347) , the developed heat flux was much greater than the corres- ponding critical values; however, the critical flux is slightly higher

than the developed heat flux in 346. This should explain why flame spread

was not sustained in experiment 346. However, it does not necessarily

explain why flashover developed in the other experiments. The peculiar

flow behavior in the doorway which preceded flashover is another factor

which must be considered in seeking a cause for flashover. Another con- tributing factor in each test, which depended on^material, was the energy

release rate due to the floor fire. Since 24 ft of floor covering was

in the room, it was a significant source of energy release compared to that

released in the corridor prior to flashover. It is clear from these four

experiments that smoke and energy produced from the combustion of the floor

material promoted higher radiation levels in the corridor, and hence,

served to accelerate the development of the fire.

17
qoTy jsn^ sauiooeg

aaT^ uiooy qoTqw

3U1T1 pazjBUixasa

None

1

1 O

<!• O

CMvD

(s)

qSnoaq^ saseaaoaQ mojj

qoxqM auiTX

o

o

1

1 O

00

cs o

ro

[ZT] peaads auiBi^ UTB^sns o:j xn-[^ 3BaH

ijUBTpB^j XBOxaxJO

0o 0.75 0.30 0.55 0.23

(ulnulxxBJ^l ao)

jaAoqsBjj

aaojaq uxui x 3J f = X

'55 3 = A =IB aooxj on xnxj

nsaH nuBxpB^j

Calculated (W/cm^)

0.70

1

1 iH

0.79

Mea- sured (W/cm^)

0.59

1

1

CVi

0.36

(Do; ("T TT 33 Z=Z

'5J OT=A ':ij V=X)

aaAoqsBXJ aaojag

asBaaauj aan^Baaduiai

SBO aopxajo3 uinuixxB^

360-390 400-500 520-610 440-550

(uxui/nng)

aaAoqsBXJ aaojag

jejjs^^U SuxaaA03

^ooTJ JO a^B^ asBajay

XSaaug pa^Buix^sa

7,000

10,300 27,400 25,800

(^33) aaAoqsBxa

aaojag saay uang

Jopxaj03 uinuixxBW

ONein lO

rH

X^xooxay^

pBajdg

auiBxa

uinmxxBj^

After Flash- over (ft/s) None <to

O

CM

ind

Before

Flashover (ft/s)

0.007 0.04

0.025 0.017

(s)

auixx aaAoqsBxa

8 o

LA00 o

<f

<f o

m

XBxaa^Bw Vinyl Sheet

Olefin Carpet

Nylon

Carpet Red

Oak

Flooring

aaquin^ nuauixaadxg

vD<f

ro

r~- en

00

<fn

e e

00 o S

o (N ro <y\ in o

O

o iH

II II II C

•He

(N

-P P

4-1 l+H CQ

<-{ .H

CO -p •Hc

3w

o

+Jco

•H

01

V4

0)>

cou

18
These experiments demonstrate the fact that flashover depends on the

interaction of the burning material and its surroundings. A fire test

method measures a fire "property" or characteristic of the material while

burning in a particular environment. Correlation of flashover with fire

test method results can be questionable unless both the test method and

fire experiment are well understood. Even with this understanding, corre- lation of flashover with a relevent fire test method may prove to be insufficient since additional parameters related to the material and its environment may be important. As an analogy, one cannot correlate beam failure

with the modulas of elasticity of the material. The load, moment of

inertia, and yield stress must also be known.

6. REFERENCES

[1] Fung, F. C. W., Suchomel, M. R. and Oglesby, P. L. , NBS Corridor

Fire Tests: Energy and Radiation Models, Nat. Bur. Stand. (U.S.),

Tech. Note 794 (Oct. 1973), GPO; SD Catalog No. C13. 46:794; $1.40.

[2] Quintiere, J. and Huggett, C. , An Evaluation of Flame Spread Test

Methods for Floor Covering Materials, Fire Safety Research,

Proceedings of a Symposium held at the National Bureau of Standards

on August 22, 1973, NBS Special Publication 411 (Nov. 1974).

[3] Christian, W. J. and Waterman, T. E., Characteristics of Full-Scale

Fires in Various Occupancies, Fire Tech., Vol. 7 (Aug. 1971).

[4] Scheffer, E. L. and Eickner, H. W. , Corridor Wall Linings — Effect

on Fire Performance, Fire Tech., Vol. 1 (Nov. 1965).

[5] McGuire, J. H., The Spread of Fires in Corridors, Fire Tech., Vol. 4

(May 1968)

.

[6] Hllado, C. J., ed. , Flammability Handbook for Plastics, Technomic,

p. 34 (1969).

[7] Birky, M. M. , Combustion Product Analysis from Full-Scale Floor

Covering Fires, Am. Chem. Soc, Polymer Preprints, Vol. 14 (Aug. 1973).

[8] Heimbold, N., ed., Textile World ~ 1968 Man-Made Fiber Chart,

McGraw-Hill (1968)

.

[9] Kanury, A. M. and Blackshear, P. L., Jr., Some Considerations Pertaining to the Problem of Wood-Burning, Comb. Sci. Tech., Vol. 1,

pp. 339-335 (1970).

[10] Bromberg, K. and Quintiere, J., Radiative Heat Transfer from Products

of Combustion in Building Corridor Fires, Nat. Bur. Stand. (U.S.),

NBSIR 74-596 (Feb. 1975).

19
[11] Block, J. A., A Theoretical and Experimental Study of Non-propagating

Crib Fires, Ph.D. Dissertation, Harvard Univ., p. C-5 (1970).

[12] Hartzel, L. G. , Development of a Radiant Panel Test for Flooring

Materials, Nat. Bur. Stand. (U.S.), NBSIR 7A-495 (May 1974).

20
APPENDIX A. RESULTS OF CARPET FIRE EXPERIMENTS IN A CORRIDOR

BY IITRI

In the course of attempting to determine the role of floor covering

materials in fires along corridors, an effort was made to obtain information from other experimental studies of this question. Illinois

Institute of Technology Research Institute (IITRI) performed carpet fire

experiments in corridors for the Carpet and Rug Institute (CRI) . The

results of these experiments were not available in the literature.

Consequently, Segall of CRI and Waterman of IITRI have supplied information from these experiments. Some of these results will be included

in this appendix for reference.

21
Appendix A-1. Letter from Bill Segall, Carpet and Rug Institute

The Carpet and Rug Institute, Suite 703, 1015 Eighteenth Street, N.W.,

Washington, D. C. 20036, 202/223-2578

January 8, 1973

Dr. James Quintiere

Fire Technology Division

National Bureau of Standards

Washington, D. C. 20234

Dear Jim:

Enclosed is a copy of the section of the IITRI report dealing with their

full-scale tests. Also enclosed is Table I giving carpet descriptions,

and another table which includes pill test results, and some tunnel test results. Unfortunately, it appears that we did not have tunnel test figures on all of the carpet.

I assume that this is not much more information about the tests than

you already have, but it is all that appears in our copy of the final

report from IITRI.

Sincerely,

William M. Segall

Vice President

Government Affairs

WMS:mb

Enclosures

22
Table I CARPET SAMPLE DESCRIPTIONS (BENCH TEST)

Approx. Pile ^prox. Total V."t. No. Fiber Type Tliickness (in.) Oz/sq yd (pil" wt.)

1 Acrylic Tufted, Level Loop .250 79 (42)

2 Acrylic Tufted, Plush .625 68 (A4)

Acrylic Tufted, Random Sliear .500 71 (46)

6 Acrylic/

Modacryllc

Tufted, Plush .625 66 (34)

10 Nylon (S) Tufted, Shag .875 62 (31)

11 Nylon (S) Tui.Led, Plush .220 68 (20)

16 Nylon (C.F.) Tufted, Multi Level .375 66 (3.5)

18 Polyester (C.F.) Tufted, Random Shear .500 81 (30)

19 Wool Tufted, Level Loop .187 66 (21)

20 Wool Tufted, Plush .500 80 (56)

21 TiifrpH ^h;^c» 1.00 90

22 Wool Woven, Level Loop .250 81 (47)

23 Acrylic/

Modacryllc

Woven, Level Loop .250 71 (42)

27 Nylon (C.F.) Tufted, Level Loop .250 68 (20)

28 Nylon (C.F.) Tufted, Level Loop 104

29 Nylon (C.F.) Tufted, Random Shear .562 58 (20)

30 Wool Woven, Cut and Loop .290 72 (41)

A Wool Woven, Cut and Loop 3/8 88 (44)

B Acrylic/

Modacryllc

Tufted, riush 13/32 75 (36)

C Polyester Tufted, Shag 7/3 72 (32)

23
COHPAR/VTIV E TF.ST Rf.SULTS

Sample E-8/» Ho. LJi-^jJh. Chamber Pill

1 62 185 - Pass

2 - - Pass

3 - - Pass

6 - - Pass

10 - - Pass

11 , - - Pass

16 - - Fail

18 - Pass

19 183 34 . - Pass

20 - Pass

21 - - Pass

22 44 64 - Pass

23 45 90 - Pass

27 65 200 - Pass

28

29 90 195 - Pass

30 49 39 - Pass

A 65 180 - Pass

. B - - Pass

C - Fall

24
Appendix A-2. Excerpt from IITRI Report to CRI

IV. FULL-SCALE TESTS

A. EXPERIMENTAL FACILITY

An existing instrumented room and cooridor CL^mplex was used to examine the full-scale behavicr of selected car jet pad

combinations o This complex consists of a 10 by 15 by 8-ft

high room connected to a 6 by 55 ft by 8-ft-=high corridor

(see Fig, 6), A 24 ft section of the corridor fleer was carpeted

as shown in Figo 6. The .carpet and pad, if used, were stapled

to asbestos silicate floor panels with standard installation

toolSo Walls of the facility are of firebrick. Ceilings are transite covered.

The primary fire source was the room. All air to the room was by fire induced draft alung the corridor floor, Ccmbustion

products exited via the upper corridor to an exhaust system at the corridor terminus. This terminus was within the main laboratory which provided a large reservoir of draft free air,

T"

-—

optical density=- log (fraction of light transmit tt-d through

Smoke)

,

IIT RESEARCH INSTITUTE

lii

25
26
The exhaust system draws on this reservoir to provide constant

stack flow irrespective of the flow within the corridor „ V/ith

constant flow, relative smoke production betweer. samples can be evaluated from light attenuation in the exhaust stack as was

done for the bench tests. In a similar manner, temperature

measurements in the stack indicate relative heat cor! c ribv:t ions

.

Thermocouples were placed through the carpet every L ft

down the corridor centerline. Additional thei mccouples were

placed along the corridor ceiling and in the room. .The rcrm fire was generated with a series of propane diifusien burners

operated at 125,000 Btu/ir.in. This "standard" fire was developed

on another program and ic based upon the burning of a number

of real contents fires within tne room space. The fire develops

2 a radiant flux intensity of 0.65 calories/cm -sec at tne floor across the corridor from the room,

B . EXPERIMENTAL PROCEDURE

At the start of each test, the room fire was initiated

and immediately taken to full intensity. This might represent

flashover of a room space and/or the sudden opening of a door

between room and corridor. Simultaneously, a small impinging

pilot flame was directed at the face of the carpet near the

doorway. This flame was used since the gas fire in the room does not emit sparks and small burning embers as would occur were the room filled with real contents items.

In addition to automatic data logging of the instrument

package, visual observations were made cf the fire progress

using small asbestos markers placed at measured points on the

carpet for reference. Carpet fire behavior was recorded during

and after the room fire burning period. A 20 min room fire

duration was used which represents the peak burning period of

the room when loaded with 5 lbs of real contents fuel \.er

square foot of floor space. An example of this level of leading is a crowded residential bedroom,

IIT RESEARCH INSTITUTE

16

27
As soon as practical after each test, the final burn pattern was carefully measured and sketched. Included wiih each

sketch were notes on the extent of charring or melting of the

pile beyond the fire zone. Comments on the condition of backing and padding within various portions of the fire zor.e were

also recorded.

C. RESULTS

Ten room corridor fire experiments were conducted. Three

of these used a 40 oz hair pad, one placed a carpet ever a ripple rubber pad, and one sample had an integral pad of sponge

rubber. In addition, a "reference" fire was conducted with a bare asbestos silicate floor. Sample descriptions and a summary

of the results are shown in Table II.

Samples 10, 18 and 19 were chosen since they received

detailed study of the effects of pads in the bench tests.

Sample 28, with integral pad, showed odd shrinkage and splitting

of the facing to expose the sponge pad. This factor plus its

high smoke production on the bench led to its inclusion.

Samples 2 and 21 showed high total burn distances on the bench even without pads (sample 2 appeared marginally capable of selfsustained combustion) and thus were included in the series.

Receipt of a second color of sample 2 by error led to its in"

elusion in the series. This second sample was run with pad to

produce what was predicted to be a "worst case" among the test

group. It should be noted that none of the samples supplied

for full-scale tests were identical (see color) to those used

for the bench tests conducted earlier. This factor assumed

significance of unexpected magnitude as will be discussed later.

Of first note in Table II is the fact that none of the

carpet samples burned as much as 8 ft beyond the room opening

(the room opens along the first 6 ft of sample). That is. none

showed behavior as hazardous as that exhibited by the group c carpet described in Section II. In fact, none burned quite as

IIT RESEARCH INSTITUTE

17

28
bCUi -~i

C ii H U *J o D»M O

CO < o<:

1^ E

^ O C

O) O V4

O D

VI o S —

•

C O ^ X

u. j:

^ u-l w

O O

O O r-.

«-« CO O

c 1- a

Wen

o —

'

CO u Q O

o <u ^,2O 4-

18

29
far as the group B carpet used previously. If assurance can

be had that the samples examined here extend over the entire

spectrum of behavior as limited by the pill test, it would

seem that, the pill test has eliminated those carpets that

would have provoked rapid total corridor involvement.

Were an external draft through the room to extend into

the corridor, one could expect the carpet to burn to greater

distances. However, the general behavior should still be one

in which the carpet essentially is burned by the room fire

while contributing little to the total fire intensity. This

can be seen in Table II by comparing corridor ceiling and ex- haust duct temperatures for experiments with carpet to those

recorded for the reference fire. That is not to say that a draft in the corridor might not enhance self ^heating of the

carpet on a local basis az the fire front by leaning the flames

into and over the unburned pile.

Some indication of conditions near the carpet surface can be seen in the temperature level of a thermocouple just above

the carpet pili^ (see Table II). It should be remembered,

however, that this 28 gauge, unaspirated thermocouple will be

radiantly heated above the local air temperature and connectively

cooled differently than the carpet fibers and thus is not a complete descriptor of either. It does, however, show striking

contrast to a corridor ceiling thermocouple which is also dis=

played in Table II.

Each full-scale fire followed the pattern of an initial

delay followed by rapid spread to involve the area directly iii front of the room opening. After this condition was reached,

further spread was at a slow, decreasing rate. No sustained

burning was encountered and the samples extinguished soon after

the room fire was ended. An indication of the rate at which

these stages evolved for each sample is sho\^m by the time for

flames to reach the carpet centerline at distances of 4 and 8 ft

from the start of the sample. The 4 ft point is still in front

IITRESEARCHINSTITUTE

19

30
of the roi).Ti of;ijaini; an-l Hk; fJanitt fr'.r.t. pi'.sijjcj chis location

while iTioviiit: acre. .-5; the ( .rvd d(->r . The S fc location is 2 ft

beyond the room opening arid, t.y rhis point, the flaiiif front

was usually turned and pcncecding djwn Llie cori idcr across its

entire width.

The range of smoke output recorded in Table II exc.aris

upward to a value about one-half that produced by a heavily

furnished real bedroom fire conducted in the same rocin as r-art of another program. It should be noted, hov;ever, that only abcut

7,5 yards of carpet vjere consumed in the corridor. Had the sarne carpet been in the room, an additional 17 yards would have been

involved to produce smoke.

31
Appendix A-3. An Analysis of an IITRI/CRI Floor Covering Test

Data supplied by Waterman from the IITRI carpet experiments were

examined. The results from a single experiment (CRI 70-010) with carpet

sample No. 28 will be considered. These results appear to be representative of most of these experiments. In this experiment, they report

that carpet ignition occurred in about 2 min (after the room fire was

initiated) . Very heavy black smoke began evolving by 8 min which filled

the corridor cross section from the ceiling to nearly the floor by 13

min. By this time, the carpet fire had advanced to 8 ft in the corridor.

At 20 min the room fire (gas burner) was turned off and a line fire con- tinued to slowly advance on the carpet. At 15 min the line fire went

out after having advanced 11.3 ft.

Gas temperature data near the corridor ceiling are shown in

figure A-1 for this test. The results at the mid-corridor position are nearly identical with previous results from tests with the same room

fire intensity, but without corridor combustible linings (Fire Tech.,

Aug. 1970). This implies a small relative energy release rate for

carpet No. 28. A burn area curve is also shown in figure A-1. After

20 min, as was pointed out, the burning area is greatly reduced as the

carpet fire becomes a line fire.

32
0 200 400 600 800 1000 1200

TIME(S) t ROOM

FIRE

OUT

Figure A-1. Results from IITRI-CRI corridor carpet burn experiments

(CRI 70-010, carpet No. 28, propane gas room fire, of 125,000 Btu/min) .

33
APPENDIX B. ESTIMATE OF THE ENERGY RELEASE RATE PER UNIT

AREA FOR THE FLOOR COVERING MATERIALS

It is assumed that the energy release rate per unit area is independent of time (invariant as the material burns in depth) and independent

of floor position (invariant as surrounding conditions change) . Before

flashover the burning area extends from the burn room to a small portion

of the corridor. Over most of this area the oxygen concentration and

heat flux from the surroundings is assumed to be fairly uniform. Hence,

the local burning rate should be fairly uniform. After flashover the

floor heat flux will generally increase tending to increase burning rate,

yet oxygen concentration is likely to drop tending to decrease burning

rate. Since these two effects have a compensating influence on burning

rate, the estimated value before flashover would still be reasonable.

Moreover, if the average burning rate was based on burn room floor covering

data where heat flux conditions are high before and after flashover, then

a realistic estimate of the mean burning rate can be determined. This was essentially done.

In general the average energy release rate per unit floor area was determined by

II AH^ •

(j) • M-. E" = — - -

F At^

, . D

where: AH = heat of combustion per unit initial mass of floor covering"'"

F

({) = fraction of combustibles in initial mass burned

• 1

1

M: = initial mass per unit area

X

At, = duration of burning at a given location,

b Experiment 346

The following data are given:

1. AHp = 12.13 MJ/kg based on the oxygen bomb calorimeter (A residue

to 38% was left in the bomb indicating a high noncombustible

content. This primarily included the inorganic felt backing.)

2. (J) ~ 1 = This is an assumption based on visible observations of the

burned area.

3. mV =3.16 kg/m^

F

4. At = 700 s based on the longest burning of floor covering in the

burn room.

9 9 E" = 54.9 kW/m (290 Btu/min f t )

.

'Sample consists of primary layer of flooring, i.e., carpet, not pad;

vinyl sheet, not adhesive; etc.

34
Experiment 347

The following data are given:

1. AR^ = 20.75 MJ/kg based on the oxygen bomb calorimeter. (A non- combustible content of 28% was indicated.)

2. <^ ~ 1 = It is assumed that the burn room carpet was completely consumed.

3. =1.86 kg/m^

4. At^ = 720 s - This is based on the earliest ignition of the burn room carpet and the time of extinguishment of the fire with

water. Although thermocouple response indicates a decrease in

floor temperature before water extinguishment, it was not

sufficient to indicate a cessation of flaming. Hence, this

burn time is approximate. Moreover, it is not uncommon for

this carpet to burn for 10 minutes or more in laboratory tests

of high heating exposure.

E" = 54.1 kW/m^ (286 Btu/ft^ min)

.

r Experiment 348

The following data are given:

1. AH-^ = 19.2 MJ/kg based on the oxygen bomb calorimeter.

r

2. 0 ~ 1 = Based on weight loss measurements of carpet after fire at

Y = 1.5 ft

3. MJ! =2.34 kg/m^

4. At^ = 350 s - This burn time is the difference between time at

extinguishment (600 s) and time of first carpet ignition in

burn room (250 s) . Thermocouple data indicate drop in temperature of flaming carpet in burn room at 500 s indicating burning

time may be shorter. Also, burning time of carpet at Y = 1.5

ft is estimated at 170 s.

e;; = 130 kW/m^ (685 Btu/ft^ min).

r Experiment 349

In this experiment wood samples of flooring from five locations were weighed after the fire. The initial weight of the samples before the

experiment was unfortunately not determined. The density of wood varies

too greatly to make estimates of weight loss based on the density of new

flooring. Hence, the original density of the burned samples was estimated

by removing the charred region from the wood and determining the density

of the relatively unpyrolyzed remainder. The results of measurements for

the five samples and two new samples of flooring are given in table B-1.

35
Table B-1

Weight Loss and Heat of Combustion Results

for Red Oak Flooring Samples in Experiment 349

JJcp Ltl OJ- Burn Hoof- fT /~\ a i~ 1 p c L unit rid bb pcL uni-C uomDUS L xon

OLlLLdL-c cd J- U IT iVfcioXQUci

(.cm; Vnj / Kg;

RnT~n Rnom 7 SI ±.\J 1 0 • u -J Z.H 90 4

Y = 2 ft 0.40 9.36 13.4 328 19.6

Y = 5 ft 0.24 9.22 10.4 128

Y = 15 ft 0.08 12.0 13.4 88

Y = 25 ft 0.16 13.7 15.6 68

New Wood 0 12.7 12.7 18.7

New Wood 0 12.0 12.0

Based on these measurements it was estimated that before flashover

(t > 630 s) the burning rate was approximately 7.04 x 10"-^ kg/m^-s and

approximately doubled after flashover. Using H^, = 18.7 MJ/kg based on

- new wood yields

, ' , E" = 132 kW/m^ (697 Btu/ft^ min)

r before flashover. If the combustible content of the char residue is considered, then this energy release rate is over estimated by approximately

25%. However, this deviation is within the extent of variation of the

initial estimate for wood density.

36
CSS""

H

m cu 3 M

a -w j-i O cfl 0) U 4-1 4-J E OJ c co

•Hae3

cnCO

)-i 0) d a

.-I S-i

<;

m

aU .-I 3 rHe o U 60co

iH cvi

m <j

37
Radiant flux incident at a floor element dA at any time is given as follows:

a" = a" + a" + a" ceiling side back

walls wall

(C-1)

where

ceiling

2 rL

tan ^( V^R)

2 3/2 R(R+a ) R^

T^(x)dx (C-2)

a = W/2

2 2 R = (d-x) + H

side

walls

ao r

2 2 R = (x-d) + H

o o

(a +R ) (a +R)

o

T (x)dx (C-3)

^back

wall

ad

TT

tan ^y^T) tan-\y/R)

^R

k\x) (C-4)

Constants

X = o

30 ft (9. 1 m)

8 ft (2. 4 m)

8 ft (2. 4 m)

4 ft (1. 2 m)

38
APPENDIX D. SI CONVERSION UNITS

In view of present accepted practice in this technological area,

U.S. customary units of measurement have been used throughout this report.

It should be noted that the U.S. is a signatory to the General Conference

on Weights and Measures which gave official status to the metric SI

system of SI units in 1960. Readers interested in making use of the

coherent system of SI units will find conversion factors in ASTM Standard

Metric Practice Guide, ASTM Designation E 380-72 (available from American

Society for Testing and Materials, 1916 Race Street, Philadelphia,

Pennsylvania 19103) . Conversion factors for units used in this paper

are

:

Length

1 in = 0.0254^ metre

1 ft = 0.3048 metre

Area

2 * -4 2

1 in = 6.4516 x 10 metre

1 ft^ = 9.2903 X 10~^ metre^

Mass

' 1 lb = 0.4536

Energy

1 Btu = 1054 J

Temperature

°C = 5/9 (Temperature °F - 32)

Power

1 Btu/rain = 17.57 W

Time

1 min = 60 s _Exact Value

39
40
(s/ai) ssoi iHOiTiM smo do 3ivy

41
50 r

0 150 300 450 600 750 900 1050 1200

TIME(S)

Figure 2b. Crib weight loss (experiment 347). (1 lb = 0.4536 kg)

42

0 200 400 600

TIME{S)

800 1000

Figure 2d. Crib weight loss (experiment 349). (1 lb = 0.4536 kg)

44
Figure 3a. Corridor flame spread (experiment 347) . (1 f t = 0.3048 m)

45
30 rP 25

u.>-

H

O 20

u.uu<

a:O

o

o

c/) o

15

10

0

0

FLAME FRONT BASED ON FLOOR TEMPERATURE = 400°C

FLAME FRONT BASED ON RAPID TEMPERATURE RISE

I 200 400 600

TIME(S)

800 1000 1200

Figure 3b. Corridor flame spread (experiment 3A8) . (1 ft = 0.3048 m)

46
Figure 3c. Corridor flame spread (experiment 349). (1 ft = 0.3048 m)

47
o

Tnco

If) >c

CO

CM

fa

IT)

CM

O

00oCO

13

CO(UOu

CO

(Ui

iH

14-1

<4-l O

Xi

4-t nJ&.

nJ

COC

o

•H

ao

3

O

CJo

g

4-)

o

o

iH

PL4

CO

•H
Figure 4b. Floor flame spread velocity. (1 ft = 0.3048 m)

49
300

250

oj 200 H

u.<

g 150

100

50

I

/ \ A

^HCLCONC.

/

\

I

\

I

f

CHAR AREA

/ BURN AREAo.

CL ^ o

O

3 O

400 600 800 1000 1200 1400

TIME(S)

gure 5a. Burn and char area with HCl concentration (experiment 346)

(1 ft^ = 0.0929 m^)

50
350

300

Figure 5b. Burn area (experiment 347). (1 ft =

51

0.0929 m^)


14

12

z

TIME(S)

Figure 6a. Energy release rate (experiment 347). (1 Btu/min = 17.57

54
Figure 6b. Energy release rate (experiment 348). (1 Btu/min = 17.57

55
EjOTAL = 34.7 X 10^ BTU/MIN

MAX

TIME(S)

Figure 6c. Energy release rate (experiment 347). (1 Btu/mln = 17.57 W)

.

56
800

0 I 1 I I I I I I 0 200 400 600 800 1000 1200

TIME{S)

Figure 7. Combustion products temperature at locations

downstream of fire (Experiment 346)

.

57
I 1 RATE OF MASS LOSS

0 100 200 400 600 800 1000 1200 1400

TIMEIS)

Figure 8a. Crib weight loss rate compared with corridor gas temperature

at X = 4 ft, Y = 10 ft, Z = 7 ft 11 in (experiment 346). (1 Ib/s = 0.4536 kg/s, 1 ft = 0.3048 m, 1 in =0.0254 m)

58
oo

UJ

a:z>

I-<

DC

LUCL

(U

h-

(/) <

m

CO<

LUo

800

700

600

500 -

400 ^-

300 -

2 2.00

100 -

-J 350

0.08

0.07

0.06

CM 300 t

<

UJ

a: 250 ^-0.05

z

z

c: 200

IlU

CL

cc 150 <

u

-100

50

C.04

0.03

0.02

0.01

JO

CO

LU<

CCCO

COo

_iCO

CO<

egcco

LU

-JC3Z

CO

1000 1200

TIIVIE(S)

Figure 8b. Crib weight loss rate, gas temperature (X = 4 f t , Y = 10 f t

,

Z = 7 ft 11 in), and burn area (experiment 347). (1 Ib/s = 0.4536 kg/s,

1 ft = 0.0929 m 1 ft = 0.3048 m, 1 in = 0.0254 m)

59
TIME(S)

Figure 8c. Crib weight loss rate, gas temperature (X = 4 ft, Y = 10 ft,

Z = 7 ft 11 in) , and burn area (experiment 348). (1 Ib/s = 0.4536 kg/s,

1 ft = 0.0929 m^, 1 ft = 0.3048 m, 1 in = 0.0254 m)

60
J I I ! 1000 1200

TIME(S)

Figure 8d . Corridor gas temperatures 1. inch (2.54 cm) below the ceiling

at Y = 10 ft (3.05 m) and Y = 20 ft (6.1 m) (experiment 349).

61
62
63
64
65
66
67
68
69
h- H H

LL U.

CNJ ^

CD

II II II XXX a • 4

o o <

m a

-4 • o < ±

O

CO

CO

CM

O

CM

LUO

z

<

I-co

CM

00

CM

o

CM

o

CM

o

LA

O O

LO

(Do) 3yniVd3dlAI31

c

(Ua

(UPU

(U

•Ho

O

+Ju

(U

4-4

(U

}-l

CO iHo

B

>^

CO CO<to

o

CO o

II C •u

<uo • —' X—

s

vO c <f o CO

•Hu u

c; •H g

V-i •H

>-i CO CU •H

CU

01

N u

CO o

>-i •H

CU 4-1 CO B CJ

CU o

4-t rH

CU CU

CJCO CO

M-l CO

!-j 0)

CO

4-) o

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• CU

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r-H

CU CO

COCU 60 B

•H

70
01 1 I I I I I I I I I I I I I 0 2 4 6 8 10 12 14 16 18 20 22 24 26 28

DISTANCE, Y (FT)

Figure lib. Floor surface temperature distribution (experiment 347).

(1 ft = 0.3048 m)

71
72
o

CO

00

CM

00o O

CO

II <

ill >oI

CO< ozz

ocD

CNJ o

CM

CO >

LUoz< - CO

00 oo I I oo oo

CO oo

CM

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(Do) 3anivy3diAi3i

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(Ue

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!-i (U

ex. 3

,Q

•H

Vj +Jm

•H

XI

(U

•u

CO

ft

(U

4-1

(Uo

CO

5-4

to

i-l oo

rH

0)

bO

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73
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z

<

Io

o

LU

>

_ o

< s

I- o

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ocD

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q:

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s-i C

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(%) aaiiiiAiSNvai AoaaNa do NOiiovad

74
CO CO O O

<N^

H I-

< <

CO 00

CD (D

z z

C Q

< <

LU LU

cc cc LU LU

H ILU LU ^ :e o g

o G

< <

cc cc

1

1

c

z

<

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-J

J-

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CC

LU

CL

CL

D

G

LU

00

CQ LU

00 CC

LU Z)

< cc > LU

LUQ|«^ <

^"

-I c:? D z

< LU

o o

L

O

CO

00

CSJ

o

CD

CM

LL

LU

O

z

<

coG

CO

o CO CO CM CO

d

CO

d d

CN

d

00o

m

o

II

(giAio/M) aooid ivxmd iNviava

0)e

•H

PO

P

CO

d

•HTJ

nJ

J-i

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cu •HO

fi M

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Pi4

75
76
77
78
1200 —o- 10 IN. FROM TOP —°— 29 IN. FROM TOP

-A— 50 IN. FROM TOP

TIMEIS)

Figure 14b. Exit velocities at doorway (experiment 348). (1 ft/min = 0.00508 m/s) 70
1200 r

1000 -

800 -

o

o

UJ>

600 -

200

400 -

-o- 10 IN. FROM TOP, EXHAUST

-o- 29 IN. FROM TOP, EXHAUST

50 IN. FROM TOP, EXHAUST

+ 9 IN. FROM BOTTOM, INFLOW

Q) IGNITION OF FLOOR IN BURN ROOM

® IGNITION OF FLOOR IN CORRIDOR

(3) FLASHOVER

@ EXTINGUISHMENT

1000

TIME(S)

Figure 14c. Exit and inflow velocities at doorway (experiment 349).

(1 ft/min = 0,00508 m/s)

80
81
Figure 15b. Estimated fuel potential burning rate of room fire

(experiment 348). (1 Ib/min = 0.00756 kg/s)

82
TIME(S)

Figure 15c. Estimated fuel potential burning rate of room fire

(experiment 349). (1 Ib/min = 0.00756 kg/s)

USCOMM NBS-DC

NBS-114A (REV. 7-73)

U.S. DEPT. OF COMM. BIBLIOGRAPHIC DATA

SHEET

1. iniBLK ATION OK Rl' I^OK C NO. NBSIR 75-691

2. C>ov't Accession

No.

3. R(( ipient's Accession No.

4. TITLE AND SUBTITLL

A CHARACTERIZATION AND ANALYSIS OF NBS CORRIDOR FIRE

EXPERIMENTS IN ORDER TO EVALUATE THE BEHAVIOR AND

PERFORMANCE OF FLOOR COVERING MATERIALS

5. Publication Date June 1975

6. Performing Organ i /.at ion (ode

7 AT fTHOR f "s^ James Quintiere

8. Performing Organ. Report No.

9. PERFORMING ORGANIZATION NAME AND ADDRESS

NATIONAL BUREAU OF STANDARDS

DEPARTMENT OF COMMERCE

WASHINGTON, D.C. 20234

10. Project/Task/Work Unit No. 49156 /b

11. Contract/Grant No.

12. Sponsoring Organization Name and Complete Address (Street, City, State, ZIP)

same as No. 9

13. Type of Report & Period Covered

Final Report

14. Sponsoring Agency Code

15. SUPPLEMENTARY NOTES

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

bibliography or literature survey, mention it here.) Data is presented for four fire experiments which examine the fire propagation

from a room fire to a floor covering material in a corridor. The four floor covering

materials include a nylon and an olefin carpet, vinyl sheet, and red oak flooring.

Limited flame spread occurred for the vinyl sheet material; however, the three other

materials involved full fire propagation in the corridor. The data are analyzed to

examine the factors influencing fire propagation. Included in this analysis is the

rate of energy contribution from the room fire and floor covering material, the rate

of flame spread, heat transfer to the floor covering, and flow interactions between

the room and corridor. A review of previous related experiments is also presented.

17. KEY WORDS (six to twelve entries; alphabetical order; capitalize only the first letter of the first key word unless a proper name; separated by semicolons) Qorridor fire Spread; energy release rate; fire induced flow;

flame propagation; flashover° floor coverings; radiant heat flux.

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21. NO. OF PAGES

1

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22. Price

t^J Order From National Technical Information Service (NTIS)

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