AlllOD NBS

PUBLICATIONS

AlllOb M07DSt.

NBSIR 81-2386

Airflow Extinguishment of Burning

Apparel Fabrics

I

Man-Made Fiber Producers Association, Inc. Washington, DC 20036

and

U S. DEPARTMENT OF COMMERCE

National Bureau of Standards

National Engineering Laboratory

Center for Fire Research

Washington, DC 20234

October 1 981

Final Report

Issued December 1981

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or rrANDAKM

NBSIR 81-2386

AIRFLOW EXTINGUISHMENT OF BURNING

APPAREL FABRICS

FEB 3 1982 rlox ' I ' ‘ Quco

. tj

A'6' 't\ O < i

B. B. Hibbard

Research Associate

Man-Made Fiber Producers Association, Inc. Washington, DC 20036

and

J. F. Krasny, E. Braun, and R. D. Peacock

U.S. DEPARTMENT OF COMMERCE

National Bureau of Standards

National Engineering Laboratory

Center for Fire Research

Washington, DC 20234

October 1 981

Final Report

Issued December 1981

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

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

Page

LIST OF FIGURES iv

LIST OF TABLES iv

Abstract 1

1. INTRODUCTION 2

1.1 Federal Regulatory Actions 2 1.2 Potential Burn Injury 3 1.3 Ease of Extinguishment 4

2. EXPERIMENTAL 9

2.1 Description of AFMA 9

2.2 Calibration of AFMA Sensors 16

2.3 Description of Airflow Generating Apparatus 17

2.4 Data Acquisition and Computation 17

2.5 Fabrics 20

2.6 Airflow Simulation Procedure 20

3. RESULTS AND DISCUSSION 21

3.1 Regular AFMA - Stationary Mode 21

3.2 Three-Inch Extension Apparatus for AFMA 21

3.3 Influence of Fabric Weight Upon Airflow

Extinguishment 28

3.4 Fabric Classification by Ease of Airflow

Extinguishment 31

4. CONCLUSIONS 31

5. REFERENCES 33

iii
LIST OF FIGURES

Page

Figure 1. Apparel Fire Modeling Apparatus (AFMA) 10

Figure 2. Apparel Fire Modeling Apparatus (AFMA) (Details) H

Figure 3. Three-Inch Extension Apparatus 14

Figure 4. Airflow Generating Apparatus 18

Figure 5. Burn Injury Area vs Airflow Rate 22

Figure 6. Maximum Total Heat vs Airflow Rate (Regular AFMA) .... 23

Figure 7. Burn Injury Area vs Airflow Rate 25

Figure 8. Maximum Total Heat vs Airflow Rate 26

Figure 9. Time to Extinguishment vs Airflow Rate 27

Figure 10. Total Heat and Burn Injury Area vs Fabric Weight 10

LIST OF TABLES

Table 1. Airflow Extinguishment Data - Regular AFMA 13

Table 2-1. Airflow Extinguishment Data - Three-Inch Extension

Apparatus - AFMA 15A

Table 2-2. Airflow Extinguishment Data - Three-Inch Extension

Apparatus - AFMA 15B

Table 3. Fabric Classification by Ease of Airflow

Extinguishment 29

\ IV
AIRFLOW EXTINGUISHMENT OF BURNING APPAREL FABRICS

B. B. Hibbard , J. F. Krasny, Braun, and R. D. Peacock

Abstract

The heat output of a burning fabric subjected to

a frontal airflow at various velocities was measured

behind the burning face of the fabric. Twelve different commercial fabrics were evaluated in this manner on

the Apparel Fire Modeling Apparatus (AFMA) . When the

fabric burned to a given heat output, the selected

level of airflow was applied to the face of the burning

fabric in an attempt to extinguish the flame. Burn

injury area, maximum total heat, and time to extinguishment were determined from AFMA data.

The burning fabrics quickly extinguished with an airflow of 213 meters per minute (8 mph) or less in all

but one of the fabrics studied. The one exception was

an 85/15 cotton/polyester double faced terry cloth

This work was done while Dr. Hibbard served as the NBS Research Associate

representing the Man-Made Fiber Producers Association, Incorporated,

during the period 1977-1979. Dr. Hibbard's current address is the Badische

Corporation, Williamsburg, Virginia.

1
fabric where this and higher airflows only increased

the rate of burning. For the eight cellulose containing fabrics investigated the maximum total heat and

burn injury area increased as fabric weight increased.

For most of the fabrics studied the total heat transferred to the simulated body generally decreased with

increasing air velocity. Fabrics were classified into

three groups based upon these airflow extinguishment

parameters

.

Key words: Airflow; burn (injuries) ; extinguishment;

fabrics; fire modeling; flammability; textiles.

1 . INTRODUCTION

1.1 Federal Regulatory Actions

The potential hazard and possible burn injury which might result

from general wearing apparel fires have been studied over the past

several years. Possibly the earliest federal regulatory action taken

to reduce this potential for burn injury was the adoption of the

Commercial Standard 191-53 test method and regulation which were

effective in eliminating some of the most hazardous fabrics. CS 191-

2 53 (Revised) is currently in use [1] .

Work at the National Bureau of Standards (NBS) and elsewhere

over the past few years has been directed towards the investigation

of the flammability of general wearing apparel. Support for this

effort was given by the U.S. Consumer Product Safety Commission

Numbers in brackets refer to the references at the end of this report.

2
(CPSC) which was assigned responsibility for the Flammable Fabrics Act

on May 14, 1973. A draft proposal by NBS entitled "Proposed Standard

For the Flammability of General Wearing Apparel" [2] was submitted to

CPSC in February, 1976. This proposal was further supported by Braun, E.,

et al. in a detailed back-up report [3] which discusses the reasons for

the choices of experimental arrangement for the flammability test and

the choice of pass-fail criteria. To date CPSC has not proposed a new

regulation for general wearing apparel.

However, specific regulatory actions have been taken with respect

to children's sleepwear in DOC FF 3-71 [4] and DOC FF 5-74 [5] as amended [6]

The amendments delete the requirements for residual

flame time of melt drip (a parameter of self-extinguishment) in DOC

FF 3-71 and revise the method of testing trim in both standards. CPSC

issued these amendments to reduce the necessity for the use of chemical

flame retardants (FR) on fiber and fabrics used in children's sleepwear.

Changes in the residual flame time requirements eliminated the requirement that the melt drip from certain burning fabrics self-extinguish

within 10 seconds.

1.2 Potential Burn Injury

Potential burn injury from apparel fabric fires was the concern of

this work. More specifically this work was concerned with the extent of

second or third degree burns to the body. Methods of determining second

and third degree burns have been reported by Derksen [7], Stoll [8,9],

Chianta [10] , Evans [11] , and others.

3
The potential of a burning garment to cause burn injury to the

human body is a complex function influenced by the following: 1)

skin characteristics

2)

ease of ignition of fabric

3)

rate and direction of flame spread

4)

weight and composition of combustibles

5)

special garment configurations (i.e., tight or loose)

6)

ease of extinguishment

7)

human reaction.

1.3 Ease of Extinguishment

In this study we were primarily concerned with the ease of extinguishment of single layered, unseamed fabrics. In particular, we were to

measure the frontal airflow extinguishment of fires of a variety of

fabrics

.

Several papers have been published on the topic of ease and extinguishment of apparel fabrics. As early as December 1973, Mayer [12] reported

on his work to measure the relative hazard of fabrics based on flame

spread. He further noted that "no effort to determine ease of ignition

4
and ease of extinguishment has been made. Any future work designed to

characterize the potential hazard of flammable fabrics must take these

factors into consideration".

In 1973, Buchbinder [13] reported that human behavioral patterns in

1,126 apparel fire accident cases showed that "running" was the most

frequent first action after apparel ignition followed in order by "beating

flames with hands" and "trying to remove clothing". Other actions such

as "wrapping in a rug" or "rolling" were noted. Often more than one

extinguishing method was used. Removing the burning clothing was

apparently the most successful method in keeping the injury small, while

the often recommended wrapping in a rug or similar heavy fabric resulted

in larger injuries, perhaps because the heat is confined near the body.

In 1974, Bauer [14] suggested three devices which might be adapted

to simulate three apparel fire extinguishing methods suggested by known

human responses. He chose (possibly tongue in cheek) to call them; 1)

"Pat-It-Out" , 2) "Blow-It-Out" , and 3) "Roll-It-Out" . Pat-it-out and

roll-it-out would essentially deprive the garment of oxygen by bringing

it in contact with surfaces (which also function as heat sinks) on both

sides. It has, however, also been noted that many fabrics stop burning

upon one-sided contact with a simulated body or living skins [15,16,17].

These findings suggested various approaches to designs of laboratory

tests for extinguishment, taking into consideration single- and two-sided

contact of fabrics with surfaces, the heat sink and oxygen exclusion

effects, and the effect of increased airflow, as in running. The mechanistic and material aspects of extinguishment of burning textiles are

analyzed in the first of a series of papers from the University of

Maryland [18]

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construction, while the heat flux was basically fiber dependent. As

expected, the burning rate increased with increasing oxygen concentration. It also decreased with decreasing distance from the heat sink,

while raising the temperature of the heat sink from 37 to 110°C had no

measurable effect.

Zawistowski, et al. [16] and Meierhoefer, et al. [17] measured

heat transfer from fabrics which were initially permitted to burn

freely but at some time after ignition were brought in contact with a simulated body. Many fabrics so tested extinguished upon contact with

the body, called the Apparel Fire Modeling Apparatus (AFMA) . It is

described under 2.1, below. It contains 54 heat sensors, and the heat

transferred from the burning specimen was measured periodically. Total

heat transferred to the AFMA was found to be fiber dependent, with

thermoplastic, FR, and wool fabrics showing the least heat transfer.

Fabrics which made poor contact with the AFMA (e.g., terry cloth and

fabrics which seemed to shrink away from the AFMA surface such as some

acetates and acrylics) resulted in relatively high heat transfer.

(Meierhoefer measured the heat transfer from 58 apparel fabrics which

had been choosen by the American Textile Manufacturers Institute (ATMI)

for the Cooperative Apparel Fire Accident Flammability Program, and

which were also evaluated by approximately 16 other accident simulation

and flammability testing methods in 15 laboratories [23,24,25], so that

the AFMA results can be compared with those of other evaluation methods.)

Miles used the AFMA to evaluate cellulosic fabrics FR treated to levels

which did not allow them to pass the Children's Sleepwear test but

which still did not seem to burn as vigorously as untreated fabrics

(borderline fabrics) [26,27]. Those fabrics transferred little heat to

the AFMA.

7
Several workers investigated the effect of air currents on

extinguishment of burning fabrics. The above mentioned borderline

fabrics were used in such experiments [27] and again transferred little

heat and extinguished readily. Le Blanc [28] reported experiments with

burning cotton and polyester/cotton fabrics which were moved at various

speeds. The potential burn injury increased with decreasing rate of

movement, and with increasing time between ignition and start of movement. Le Blanc [29] also reported on methods which extinguished burning

fabrics in various ways, including dropping, jarring, touching, and

blowing on them. Again, certain borderline cellulosic fabrics (which

had been treated with levels of flame retardants somewhat less than

that needed to make them self-extinguishing in vertical tests) were

readily extinguished by these methods. Finally, Pressley [30] mentions

a demonstration of airflow extinguishment by moving pieces of burning

fabric in the air.

Potthof, et al. [31] investigated the air patterns behind a running

person and the heat evolution from burning fabrics exposed to air

streams of varying velocity. Behind a running person, the airflow can

recirculate and flames can burn vigorously even though they extinguish

in front. Some fabrics showed first increasing, then decreasing heat

evolution with increasing air speed, and for others the heat evolution

decreased fairly linearly with air speed. Air streams did not extinguish fabrics which form chars and which had started to burn on the

inside

There was a common thread between the results of the various

extinguishment experiments: fabrics which evolved little heat when

they burned in still air generally were easily extinguished by any of

8
the methods discussed above. If, in addition, such fabrics also do not

ignite easily, they could be considered relatively "low risk".

2 . EXPERIMENTAL

The objective of the work reported here was to characterize the

effectiveness of frontal airflow alone upon the extinguishment of

burning apparel fabrics. More specifically, we wished to exclude the

effects of solid heat sinks and reduced oxygen concentrations. The

AFMA was modified and a device to achieve airflow of 0-8 miles per hour

was constructed to simulate the running of a potential victim. Airflow

was initiated at the given thermal recognition point of a 5°C temperature rise at the AFMA body surface. The time to extinguish, area

burned, percent of second degree or greater burn injury, and maximum

total heat are reported as measures of ease of airflow extinguishment.

2.1 Description of AFMA

The Apparel Fire Modeling Apparatus (AFMA), described in detail in

earlier publications [17,18], was modified and recalibrated for this

study. The AFMA is a vertically mounted semi-cylinder 58 cm (23 in)

high and has a diameter of 18 cm (7.1 in) (figure 1) . The surface of

the semi-cylinder is almost completely covered by 54 blackened copper

sensors. The sensors are 7.6 x 2.5 cm (3.0 x 1.0 in), and are separated by 0.3 cm strips of mineral board (figure 2). The total area of

2 2 sensors is approximately 1050 cm (163 in ) . Heat transferred to each

sensor is recorded electronically every 3 seconds. Fabric is cut to

pattern using a special aluminum platen so that the desired direction

of the fabric will always be mounted in the vertical direction.

9
10

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Modeling

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DETAILS

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Figure

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Apparatus

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(Details)
This platen allowed for corner adjustments and had a hole for

marking the point of ignition at the center 12 cm (4.75 in) up from the

bottom edge of the fabric. In most cases the machine direction of the

fabric was mounted vertically.

Initial experiments were run using the AFMA in the stationary mode

only (figure 1). Results are shown in table 1. Visual observations

showed that even modest frontal airflow rates caused some of the free

hanging fabrics to contact the AFMA body and thus be extinguished in

part by the heat sink capacity of the AFMA rather than by airflow

alone.

To eliminate this effect from this study, a 3-inch extension

apparatus was designed and constructed. The two vertical stainless

steel rods and the outer support member did not serve as a significant

heat sink. Thus the fabric was gently held at a distance of 7.6 cm

(3.0 in) from the AFMA at all points (figure 3). Data using the 3-inch

extension apparatus are presented in table 2.

The 3-inch extension apparatus was closed at the top with a solid

metal plate. A flame-retardant fabric backing of fiberglass or Nomex

aramid fabric was snugly fastened with clamps to cover the entire back

portion of the AFMA. Thus a pant leg or slender torso with a top

closure or belt was most nearly simulated. This technique eliminated

what might be any "chimney effect".

12
Airflow

Extinguishment

Data -

Regular

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14
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A monitoring circuit follows the temperature of four sensors

located at various heights in the center column on the AFMA. When any

one of these four sensors register a temperature rise of 5°C there is

an audible sound and a visible light which signals the manual initiation of the airflow. Recognition time is the time in seconds from

fabric ignition to this signal. This 5°C temperature rise was selected

as that which would probably be sufficient to be perceived by a person

who then may respond by running.

2.2 Calibration of AFMA Sensors

The constants for each of the 54 sensors on the face of the AFMA

were recalibrated individually using a voltage controlled heat lamp as

the radiative heat source. The average values for duplicate runs were

placed into the computer program. In previous work the sensor constants

were determined in banks of 5 using a heated quartz panel (Casso-Solar

Heater, Type "C"). The difference between sensor constants determined

for this study as well as the work of Miles [26,27] and those used in

earlier work [17,18,20] is primarily due to the calculation of the

initial slope at a shorter time of exposure used, generally 10-20

seconds, rather than use of a "calculated slope" at 60 seconds of

radiant heat exposure. The temperature as a function of time curve was

non-linear after 30 seconds, most likely due to conductive and convective heat losses from the sensors. In many actual runs the time for a given sensor to reach maximum heat was 30 seconds or less as shown in

computer print outs. This time is different than that time at maximum

heat for all sensors which is shown in tables 1 and 2, and different

from the total burn time which may run up to 120 seconds or even longer.

16
2.3 Description of Airflow Generating Apparatus

The purpose of this apparatus is to supply room air with a steady

flow from zero to approximately 8 miles per hour (zero to 700 ft/min)

(zero to 213 m/min) . This upper limit was selected to represent the

top running speed of a person. A furnace blower fan driven by an

electric motor using various belts and pulleys allowed us this full

range of airflow (figure 4)

The final airflow was measured with a Thermal Anemometer at a point 5.1 cm (2.0 in) irt front of the fabric at the point of ignition.

Airflow rates of 0, 45, 76, and 213 m/min + 5 m/min (0, 150, 250, and

700 ft/min + 15 ft/min) were essentially uniform across the face of the

’ • 2 2 specimen, 33.0 cm x 38.1 cm = 1260 cm (13 in x 15 in = 195 in )

in no case did the ;airf low cause the fabric to touch the body of

the AFMA. • ^

2.4 Data Acquisition and Computation

The data acquisition and computations were carried out as in

previous AFMA, work including the use of the burn injury area concept.

The heat sensors of the AFMA surface were scanned every 3 seconds and

the thermocouple outputs were recorded electronically and processed by

computer to yield equivalent heat flux values for each sensor.

17
Figure 4. Airflow Generating Apparatus

18
In addition to the heat transferred to each sensor, an estimation

of burn injury area was made for each sensor. The burn injury area

described here is an estimated second-degree or greater burn based on

the work of Derksen [7]

,

in which the heat-exposure rate relationship

for second-degree burns was experimentally determined. The number of

"injured" sensors was determined for each 3-second interval from time

of ignition, and used to calculate the burn injury area reported in

tables 1 and 2. Consideration of the burn injury area along with the

total heat delivered to this area permits a relative comparison of the

depth of injury which may be caused by the burning of the various

fabrics. It must also be noted that the heat sensors are blackened

copper with thermal characteristics quite different from those of human

skin. The burn injury area concept thus is an approximation, but

permits a comparative ranking of fabrics in terms of their burn injury

potential

Total heat and maximum total heat are reported in tables 1 and 2.

Total heat is reported in calories at a given time (seconds from fabric

ignition) when the total heat is at a maximum. More specifically, total

heat is determined at the time when the sum of the heat registered by

each of the 54 sensors is at a maximum. Maximum total heat is also

reported in calories, but is determined by the summation of the maximum

heat for each sensor regardless of the time for each sensor to reach

this maximum. Maximum total heat is always larger than the total heat

determined at a given time. The magnitude of the difference between

these two values is influenced primarily by the rate of burning.

19
2.5 Fabrics

The fabrics used in this work were generally selected from those

supplied by ATMI for the Cooperative Apparel Fire Accidents Flammability

Program. The fabrics were representative of the range of fiber and

fabric types presently in common use but also included a few experimental fabrics. The 12 fabrics used in this work are described in table 2.

2.6 Airflow Simulation Procedure

The samples were prepared from washed fabric (AATCC Test Method

124-1967) and conditioned in a room maintained at approximately 23°C

and a relative humidity of 40 percent. The samples were then mounted

on the modified AFMA. A paper tab, ignited with a match, placed 12 cm

(4.75 in) up from the bottom edge served as the ignition source. Upon

ignition of the fabric, a stopwatch was started to determine the time

until the temperature of one of the four monitored sensors increased by

5°C. This was called the recognition time. Airflow was started at

this time.

At ignition of the fabric, the data acquisition system was started

and allowed to scan the sensors during the burning of the fabric and

for about 15 seconds after the last evidence of fabric combustion. For

those fabrics which would not ignite with surface ignition, a second

attempt was made by ignition at the bottom edge with a paper tab ignited

with a match.

After each experiment, all heat sensors were allowed to cool until

the potential from the thermocouples was 0.025 mv or less. If indicated,

the sensors were cleaned and repainted.

20
3. RESULTS AND DISCUSSION

3.1 Regular AFMA - Stationary Mode

The first set of experiments was run without the use of the 3-inch

extension apparatus'and with the AFMA in the vertical and stationary

mode. There were strong indications from the data shown in table 1 and

in figures 5 and 6 that ah airflow of as little as 45.7 m/min (150

ft/min) significantly reduced the burn injury potential for three of

the four fabrics studied. However, it was readily observed that the

free-hanging fabric specimen was blown towards and, at times, touched

the AFMA body. When contact was made the flame was usually extinguished. The AFMA body served as a heat sink. Extent of such contact

varied with fabric specimen orientation. This may, in part, explain

the differences seen in runs on the same fabric performed in the

machine direction (W) and perpendicular to that direction (F) . As we

wished to determine the contribution of airflow rate only, the 3-inch

extension apparatus was designed, constructed and used in all additional

runs.

The terry fabric (Fabric A-50) was not extinguished by this frontal

airflow rate, but resulted in nearly the same burn injury potential

with or without airflow. This evaluation is based upon greater burn

injury area and only slightly differing maximum total heat to the AFMA

(figures 5 and 6)

3.2 Three-Inch Extension Apparatus for AFMA

Data for runs using the 3-inch extension apparatus are shown in

table 2. Use of this apparatus essentially eliminated fabric contact

with the AFMA surface and thus the heat sink effect. Note that the

21
0 50 100 150 200

AIRFLOW RATE, Ft/min.

Figure 5. Burn Injury Area vs Airflow Rate (Regular AFMA)

22
MAXIMUM

TOTAL

HEAT,

CALORIES

ffC-.'

0 50 100 150 200

AIRFLOW RATE, Ft/min.

Figure 6. Maximum Total Heat vs Airflow Rate (Regular AFMA)

23

t
burn injury area and maximum total heat values are different from those

shown in table 1 for the same fabrics due to the different fabric

configurations used. In the case of the free hanging AFMA configuration

the fabric was 13.3 cm (5.25 in) away from the AFMA body at the bottom

and only 0.64 cm (0.25 in) at the top (figure 1) . In the case of the

3-inch extension apparatus the fabric was supported 7.6 cm (3.0 in)

from the AFMA body at all points (figure 2). Use of the 3-inch extension apparatus also required larger fabric samples (more potential

fuel)

These data confirm the results shown in table 1 that increased

airflow rates generally reduce the potential burn injury. More specifically, in figure 7 the burn injury area is effectively reduced except

for the terry fabric A- 50. In figure 8 the maximum total heat was

reduced in each case, however, fabric A-50 showed less reduction in

maximum total heat than the other fabrics. As shown in figure 9, the

time to extinguishment was decreased with increasing airflow for most

fabrics. Again fabric A-50 showed no change at the highest airflow as the fabric would have burned fully and was extinguished by water.

The average recognition time (the time from ignition until one of

four selected sensors registered a temperature rise of 5°C) for these

fabrics were somewhat different. Note that the average values for the

fabrics in table 1 are in the same rank order as in table 2 where runs

were made using the 3-inch extension apparatus. The data taken from

these tables are summarized below:

24
0 100 200 300 400 500 600 700

AIRFLOW RATE, Ft/min.

Figure 7. Buim Injury Area vs Airflow Rate (Three-Inch Extension Apparatus)

25
MAXIMUM

TOTAL

HEAT,

CALORIES

T

0 100 200 300 400 500 800 700

AIRFLOW RATE, Ft/min.

Figure 8. Maximum Total Heat vs Airflow Rate (Three-Inch Extension Apparatus;

i

26
TIME

TO

EXTINGUISHMENT,

SECONDS

0 100 200 300 400 500 600 700

AIRFLOW RATE, Ft/min.

Figure 9. Time to Extinguishment vs Airflow Rate

(Three-Inch Extension Apparatus)

27
Fabric Identification

Average Recognition Time, Seconds

Regular AFMA AFMA with Extension

G-13 12 -

A-26 15 11

A-44 17 15

A-50 30 26

In the case of fabric G-13 using the 3-inch extension apparatus,

the AFMA did not see a 5°C rise nor was any injury observed in spite of

the fact that this lightweight acetate fabric was fully consumed by

fire

.

3.3 Influence of Fabric Weight Upon Airflow Extinguishment

The influence of fabric weight upon the ease of frontal airflow

extinguishment is clearly shown in the data of table 3. In figure 10

only the eight cotton or polyester/cotton (cellulose containing) fabrics

are considered. The parameters of maximum total heat and burn injury

area at the airflow rate of 45.7 m/min are plotted against fabric

weight. Both of these parameters increase with increasing fabric

weight. The non-cellulose containing fabrics (G-12, E-10, A-1, and A44) were all much lower in burn injury area and maximum total heat at

this airflow rate, and thus did not fit the fabric weight relationships

seen for the cellulose containing fabrics.

28
Table 3

Fabric Classification by Ease of Airflow Extinguishment

Fabric

Designation

Fabric

g/m^

Weight

oz/yd^

Max. Total

Heat, cal at

45.7 m/min

Burn Injury

Area, cm^

Group

Classification

Cellulosic

A-52 500 14.7 10,520 995 C

A-28 325 9.6 5,990 707 C

A-50 320 9.4 5,800* 720* C

A-65 175 5.1 1,010 43 B

A-26 165 4.8 2,790 536 C

G-17 85 2.5 1,240 0 B

G-10

Non-iCellulosic

70 2.0 1,700* 140* B

G-12 , nylon 85 2.5 <50* 0 A

G-13 , acetate 110 3.2 800* 0* A

E-10 , polyester 250 7.3 170 0 A

A-1, polyester 285 8.4 <400* 0 A

A-44 , modacr./

acr

290 8.6 474 21 B

*Estimated or extrapolated from data in Tables 1 and 2.

29
3lU3 *V3HV A^mrNI N^ns

oO S ®

C3 oa S® So 2a 2o ^ cn oo CO ^ ^ c*3 es ^ CO

m

CM

C4

09

O

cs

00

CO

m

o

CM

CO CM

S3iaoivo ‘iV3H moi wnwixvw

30

Figure

10.

Total

Heat

and

Burn

Injury

Area

vs

Fabric

Weight
3.4 Fabric Classification by Ease of Frontal Airflow Extinguishment

The work of Meierhoefer, et al. [24] and this work which use the

AFMA and the AFMA with the 3-inch extension apparatus allow greater

assurance of the classification of fabrics based upon ease of extinguishment. In this study the fabrics selected were the same or very

much like those placed in five of the seven classifications defined by

Meierhoefer

Use of the 3-inch extension apparatus on the AFMA permitted the

study of all fabrics, including thermoplastics. It also permitted the

measurement of the effect of airflow alone upon extinguishment.

Although the 12 fabrics studied may not represent the full spectrum

of fabrics, three groupings have been defined based upon burn injury

area and maximum total heat. Group A showed the least potential burn

hazard, while group C showed the most. Group classifications are shown

in table 3.

4. CONCLUSIONS

Burning fabrics were subjected to frontal airflov/s of varying

intensity. The heat flux to a simulated body behind the fabric specimens was measured. Most of the fabrics were extinguished by the higher

airflows, but one, a terry towel fabrics, continued to burn and deliver

heat to the simulated body even when exposed to the highest airflow

(213 m/min or 8 m.p.h). The other fabrics delivered generally less

heat to the simulated body as the airflow increased.

31
Thermoplastic fabrics (nylon, polyester, and acetate) delivered

less heat to the simulated body than cellulose containing fabrics. For

the latter, the amount of heat delivered increased roughly with fabric

weight.

Only the heat delivered to the front of the simulated body was

measured in this work. However, it has been observed in real life

situations and in the laboratory [31] that even with frontal ignition,

flames may travel to the back of garments and continue burning even if

the frontal areas extinguish.

32
5. REFERENCES

[1] Part 1610 - Standard of the Flammability of Clothing Textiles, Code

of Federal Regulations, Flammable Fabrics Act Regulations, U.S.

Government Printing Office, 420-444 (Jan. 1, 1980)

[2] Proposed Standard for the Flammability of General Wearing Apparel,

Draft 4, U.S. Consumer Product Safety Commission, Washington,

D.C. 20207 (Sept. 26, 1976).

[3] Braun, E., Cobble, V. B., Helzer, S., Krasny, J. F., Peacock, R. D.

and Stratton, A. K., Back-Up Report for the Proposed Standard for

the Flammability of General Wearing Apparel, Nat. Bur. Std. (U.S.),

NBSIR 76-1072 (June 1976)

[4] DOC FF 3-71, Children's Sleepwear, Standard for the Flammability of

Children's Sleepwear, Federal Register, Vol. 36, No. 146, 14063-

14065, 1968.

[5] Standard for the Flammability of Children's Sleepwear: Sizes 7 Through 14 (FF 5-74), Federal Register, Vol. 39, No. 85, 15210-

15228 (May 1, 1974) , as amended.

[6] Part 1615 - Standard for the Flammability of Children's Sleepwear:

Sizes 0 Through 6X (FF 3-71) , Part 1616 - Standard for the

Flammability of Children's Sleepwear: Sizes 7 Through 14 (FF 5-74),

Flammable Fabrics Act Regulations, Federal Register, Vol. 43, No. 25,

4849-4855 (Feb. 6, 1978)

[7] Derksen, W. L. , Monahan, T. I., and Delehery, G. P., The Temperature

Associated with Radiant Energy Skin Burns, Temperature - Its

Measurement and Control in Science and Industry, Vol. 3, Part 3,

171-174 (1961) .

[8] Stoll, A. M. and Chianta, M. A., Heat Transfer Through Fabrics as Related to Thermal Injury, Trans. N.Y. Acad. Science, Sec. II,

Vol. 33, No. 7, 649-670 (1971).

[9] Stoll, A. M. , The Role of the Skin in Heat Transfer, Advances in

Heat Transfer, Vol. 4, 115-136, Academic Press, New York, 1967.

[10] Chianta, M. A. and Stoll, A.M. , Heat Transfer in Protection from

Flames, Aerospace Medicine, Vol. 35, 7-10, 1964.

[11] Evans, E. I., et al.. Flash Burn Studies on Human Volunteers,

Surgery, Vol. 37, 280-297, 1955.

[12] Mayer, M. , The Use of Simulated Apparel Fire Accidents to Determine

the Relative Flammability of Fabrics, Proc. 7th Ann. Mtg. Information

Council on Fabric Flammability, New York, 263-248 (December 1973) .

[13] Buchbinder , L. B. , Human Behavioral Pattern vs. Injury Severity for

Apparel Fire Victims, Proc. 7th Ann. Mtg. Information Council on

Fabric Flammability, New York, 236-253 (December 1973) .

[14] Bauer, J., "A Proposal for Test Method for Ease of Extinguishment",

American Dyestuff Reporter, Vol. 64, 66 (November 1974) .

33
[15] Krasny, J. F. and Fisher, A. L., Laboratory Modeling of Garment Fires,

Textile Research J., Vol. 43, 272-283 (May 1973).

[16] Zawistowski, E. R. , Krasny, J. F., Braun, E., Peacock, R. D., and

Williams, N., The Measurement of Fabric Flammability Parameters in

Experiments Simulating Human Movement in Burn Accidents, Nat. Bur.

Std. (U.S.), NBSIR 77-1236, (June 1977).

[17] Meierhoefer, A. W. , Braun, E. , Krasny, J. F., and Peacock, R. D.,

Fire Accident Simulations With Apparel Fabrics, Nat. Bur. Std. (U.S.)

NBSIR 79-1755, (1979)

[18] Bhat, G. R. , Block, I., Yeh, K., and Spivak, S. M. , Extinguishability

of Flammable Textiles: Part I,- Statement of the Problem, J. of

Consumer Product Flammability, Vol. 3, 155-165 (1976).

[19] Krasny, J. F. and Francis, J. G., Ranking Extinguishability of

Burning Fabrics, Textile Chemist and Colorist, Vol. 6, No. 6,

36-37 (June 1974)

[20] Fairall, P. A., The Influence of Selected Test Parameters on

Extinguishability of Fabrics, Master's Thesis, University of Maryland,

Department of Textiles and Consumer Economics (1976).

[21] Tesoro, G. and Backer, S., Extinguishment in Apparel Textiles, NBS

Grant No. 4-9024, Final Report, Nat. Bur. Std. (U.S.) NBS-GCR6-76-71

,

(1976) .

[22] Miles, L., Bhat, G. R. , Sun, R. L., Yeh, K. and Spivak, S. M.

,

Extinguishability of Flammable Textiles: Part II - Effects of Ambient

Oxygen Concentration, J. of Consumer Product Flammability, 3, 166-192

(1976): Part III - Effects of Cooler, Inert Bodies, J. of Consumer

Product Flammability, Vol. 5, 135-162 (Sept. 1978).

[23] Bercaw, J. R. and Jordan, G. K. , Injury From Burning Garments,

Pro. 8th Ann. Mtg., Information Council on Fabric Flammability,

New York, 214-239 (December 1974).

[24] Bercaw, J. R., Industry Program on Thermo-Man and Its Relation to MAFT

and Other Predictive Apparel Flammability Tests: Status Report,

Proc. 10th Ann. Mtg., Information Council on Fabric Flammability,

338-356 (December 1976)

[25] Bercaw, J. R. , Industry Apparel Flammability Program, Proc. of

the 1978 Symposium on Textile Flammability, 75-92 Le Blanc Research

Corporation, East Greenwich, Rhode Island 02818 (April 1978)

[26] Miles, L. B., The Burning Behavior of Borderline Fabrics, Proc.

of the 1977 Symposium on Textile Flammability, 66-96, Le Blanc

Research Corporation (April 1977) .

[27] Miles, L. B., An Investigation of the Flammability Hazard of Apparel

Fabrics, Proc. 6th Symposium on Textile Flammability, 38-74, Le Blanc

Research Corporation (April 1978) .

34
[28] Le Blanc, R. B. and Di Carlo, J. P., Tests for Ease of Extinguishment,

Proc. 5th Symposium on Textile Flammability, 39-65, Le Blanc Research

Corporation, East Greenwich, Rhode Island (1977).

[29] Le Blanc, R. B. and Di Carlo, J. P., Four Small Scale Tests for

Flammability, Textile Chemist and Colorist, Vol. 10, 241-246, 1978.

[30] Pressley, T. A., Fincher, K. W. , and Rowlands, R. J., Textile

Flammability Testing, Textile Journal of Australia, Vol. 48, (2),

18-21, 38-40, 1973.

[31] Potthoff, P. A., Sun, R. L. , Derrick, F. W. , and Spivak, S. M.,

Extinguishability of Flammable Textiles: Part IV: Effects of Air

Flow, Journal of Consumer Product Flammability, Vol. 6, 261-287

(Dec. 1979) .
NB$"]14A (REv« 2 «ec) U.S. DEPT. OF COMM.

BIBLIOGRAPHIC DATA

1. PUBLICATION OR 2 REPORT NO.

SHEET (See instructions) NBSIR 81-2386

. Performing Organ. Report NoJ 3. Publication Date December 1981

4. TITLE AND SUBTITLE

AIRFLOW EXTINGUISHMENT OF BURNING APPAREL FABRICS

5, AUTHOR(S)

B.B. Hibbard, J.F. Krasnv. E. Braun, and R.D. Ppponrk

6. PERFORMING ORGANIZATION (If joint or other than NBS. see instructions)

Man-Made Fiber Producers National Bureau of Standards

Association, Inc. and Department of Commerce

Washington, D.C. 20036 Washington, D.C. 20234

7. Contract/Grant No.

8. Type of Report & Period Covered

Final Report

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

10.

supplementary NOTES

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

11.

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

bi bl iography or literature survey, mention it here)

The heat output of a burning fabric, subjected to a frontal airflow at various

velocities, was measured behind the burning face of the fabric. Twelve different

commercial fabrics were evaluated in this manner on the Apparel Fire Modeling

Apparatus (AFMA) . When the fabric burned to a given heat output, the selected

level of airflow was applied to the face of the burning fabric in an attempt to

extinguish the flame. Burn injury area, maximum total heat, and time to

extinguishment were determined from AFMA data.

The burning fabrics quickly extinguished with an airflow of 213 meters per minute

(8 mph) or less in all but one of the fabrics studied. The one exception was an 85/15 cotton/polyester double faced, terry cloth fabric where this and higher

airflows only increased the rate of burning. For the eight fabrics investigated

which contained cellulose, the maximum total heat and burn injury area increased

as fabric weight increased. For most of the fabrics studied, the total heat

transferred to the simulated body generally decreased with increasing air velocity.

Fabrics were classified into three groups based upon these airflow extinguishment

parameters

.

12.

KEY WORDS (Six to twelve entries; alphabetical order; capitalize only proper names; and separate key words by semicolon s) Airflow; burn (injuries); cotton; fabric flammability; fabrics; fire suppression;

flame extinguishment; heat transfer; polyester; textiles.

13.

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