UNITED STATES DEPARTMENT OF COMMERCE • Charles Sawyer, Secretary

NATIONAL BUREAU OF STANDARDS . E. U. Condon, Director

Fire Tests of Bulb-Type

Carbon-Tetrachloride Fire Extinguishers

by O. J. Hodge

National Bureau of Standards Miscellaneous Publication 197

Issued May 8, 1951

For sale by the Superintendent of Documents, U. S. Government Printing Office, Washington 25, D. C. : Price 10 cents
Preface

The National Bureau of Standards has received numerous inquiries relative

to the effectiveness of small bulb-type carbon-tetrachloride fire extinguishers,

not only when used as hand extinguishers for first-aid fire protection but also when employed for the automatic protection of enclosed spaces. This paper gives the results of some fire tests that the Bureau's Fire Protection Section has made of devices of this sort. The information is intended

to assist in the evaluation of fire extinguishing equipment of smaU capacity.

E. U. Condon, Director.

ii
Contents

Page Preface n

I. Introduction 1 II. Description of devices tested 1 III. Tests of devices as hand extinguishers 2

1 . Results of tests 2

2. Summary and discussion of results 3 IV. Tests of devices as automatic extinguishers 3

1. Extinguishers A to F 3

(a) Results of tests 4

(1) First test with two extinguisher units 4

(2) Second test with four extinguisher units 4

(b) Summary of results 6

2. Extinguisher G 6

(a) Results of tests 6

(1) First test with two extinguisher units on class A fires. 6

(2) Second test with three extinguisher units on class B

fires 7

(b) Summary of results 7 V. Conclusions 8

in

Fire Tests of Bulb-Type Carbon-Tetrachloride

Fire Extinguishers

O. J. Hodge

Results are given of fire tests on samples of seven different bulb-type carbon-tetrachloride

fire extinguishers ranging in capacity from 0.44 to 1.75 quarts. Six of the extinguishers were

tested both for manual and automatic operation. The seventh device was tested for auto- matic operation only, since it was not designed for manual use. The tests of the devices as automatic extinguishers were conducted in a room with

ventilation just sufficient to permit the test fires to burn freely until the fuel was consumed,

with no extinguishers present. The test results showed that the bulb-type carbon-tetrachloride fire extinguishers, as represented by the samples tried, when operated by hand were distinctly less effective than

the ordinary one-quart carbon-tetrachloride pump-gun extinguisher, and when employed as automatic devices were not effective for the protection of the enclosed space. The seven

devices were tested in the number recommended by the manufacturer and six of them were

also tried in double that number.

I. Introduction

The National Bureau of Standards has conducted several series of tests to determine the

(effectiveness of bulb-type fire extinguishers using

jcarbon tetrachloride as the extinguishing agent.

|The devices investigated included seven different

[models, of which six were designed both for hand

|and automatic operation. The seventh extinguisher was designed for automatic operation

only. The capacities of the extinguishers ranged

from 0.44 qt (14 fl oz) to 1.75 qt (56 fl oz).

II. Description of Devices Tested

The six extinguishers designed for both hand

and automatic operation consisted essentially of a

glass flask or bottle containing from 0.44 to 1.00

qt of extinguishing liquid. The extinguishers

were mounted in a bracket intended to be hung

on the wall or, in some cases, from the ceiling.

The general character of the extinguishers is shown

in figure 1. The sketches are diagrammatic to

illustrate two styles of the devices tested, but do

not represent them, exactly.

For hand operation, the bottle was intended to be removed from its bracket and the contents

applied either by throwing the extinguisher into

the fire forcibly enough to break the bottle or by

sprinkling the liquid from the bottle on the fire. For automatic operation, each of the six extinguishers was equipped with a thermostatic

I device intended to release the liquid when the

i temperature at the extinguisher reached a pre- determined value. The thermostatic device was

attached to the bracket or to the extinguisher

itself. Two methods of release were included.

One permitted the bottle to fall to the floor and

break, thus discharging the liquid; the other per- mitted the liquid to sprinkle from the bottle while

still held in the bracket.

The extinguisher intended for automatic opera92S971—51 2

tion only was mounted in a bracket to be hung

from the ceiling and was especially designed to discharge 1.75 qt of extinguishing liquid in the

form of a spray when the temperature of the air surrounding the device rose above a predetermined

value.

The extinguishers included in the tests are designated by A to G, as listed in table 1

.

In all the tests of the devices designated as auto- matic extinguishers, the units were installed in

accordance with the manufacturer's instructions.

Figure 1. General character of two styles of the extinguishers tested. A, Drop-on-floor type; B, Spring-operated type.

1

( I
Table 1. Extinguishers included in the tests

Extinguisher

designa- tion

A

B

Cd

E

F.G

Amount of extinguish- ing liquid used

ft oz

14

1419

242732

56

Qt 0.44

.44 .59

.75

.84

1.00

1.75

Method of operation as hand extinguisher

Throwing

Sprinkling do Thnwirte or sprinkling Snrinkling .

.

Throwing or sprinkling

Temperature at which device was

intended to operate when used

as automatic

extinguisher

° F

150

160 160

158

160

158

170

III. Tests of Devices as Hand Extinguishers

By reason of the nature of the extinguishing

liquid employed, devices of the carbon-tetrachloride type when used as hand extinguishers are not

suitable for fires in ordinary freely burning materials such as wood, trash, and the like ("class

A" fires). The liquid is, however, effective for

fires in highly flammable materials such as gasoline, oil, and the like (class B fires)

.

As the devices tested employed an effective

extinguishing medium, the question to be answered

in the tests was whether they made available (for class B fires) a sufficient quantity of the liquid and

applied it in a sufficiently effective manner to be

of practical value. Therefore, to evaluate the

effectiveness of the devices, they were tested in comparison with the 1-qt carbon-tetrachloricle

pump-gun extinguisher, which is the smallest

extinguisher of that type generally recognized as acceptable for first-aid fire protection.

For testing extinguishers of the 1-qt carbontetrachloride pump-gun type, certain "standard"

test fires are commonly used. Among these fires are (1) a fire of 1 gal of gasoline on a 4- b}^ 8-ft floor area, and (2) a fire of }i gal of gasoline on a

4- by 4-ft floor area. For the purposes of comparative tests of the bulb-type extinguishers with

the 1-qt pump-gun extinguisher, the second, or

smaller, of the two test fires was selected first. This fire can easily be extinguished by the 1-qt

pump gun. When (as indicated in the test results given below) it was found that none of the bulbtype extinguishers could extinguish this fire when

only one unit was used, trials were made in which

a number of units were applied in succession.

Further trials were then made in which the area

of the test fire was reduced from 4 by 4 ft (16 ft2) to 3 by 3 ft (9 ft2), and the quantity of gasoline

from }o gal to 1 qt. It was found by test that this

fire could be extinguished with a 1-qt pump gun

by the use of less than one-half of its charge.

Finally, trials were made in which the area

of the original test fire was reduced to a 2- by

2

2-ft square (4 ft2) with 1 qt of gasoline as fuel. It was found by test that this fire could be extinguished with a 1-qt pump gun by the use of

only about one-half of its charge. In the tests on the 3- by 3-ft and 2- by 2-ft-area fires, only one

unit was used in each trial. Of these two fires, that on the 2-ft-sq area was the most difficult to extinguish because of the greater depth of gasoline.The tests were conducted indoors in the Bureau's

panel-furnace test building, in a room approximately 84 ft long by 36 ft wide by 30 ft high.

The gasoline was confined to the specified area on the concrete floor of the room by an edging

constructed of asbestos paste.

1. Results of Tests

The results of the tests of the devices as hand

extinguishers are given in table 2.

Table 2. Results of tests of the devices as hand extinguishers

Trial

Area

of

test

fire

Extinguisher

Desig- nation

I 'upaeity Method of operation Number

of units used

Was

fire extin- guished?

Test 1

ft qt

1 4X4 A 0. 44 Throwing No

2 4X4 B i .44 Sprinkling. . No

3 4X4 C .59 do No

4 4X4 D .75 do No

5 4X4 E .84 do No

6 4X4 F 1.00 Throwing. . No

Test 2

1 4X4 A 0.44 Throwing . 5 No

2 4X4 0 .59 Sprinkling... . 3 Yes

3 4X4 C .59 do 4 Yes

4 4X4 D .75 ___._do-.-_ 2 Yes

5 4X4 D .75 do 3 Yes

6 4X4 E .84 .....do. — 3 Yes

7 4X4 F 1.00 Throwing 4 No

Test 3

1 3X3 C 2 0. 59 Sprinkling.. No

2 3X3 C .59 do. No

3 3X3 D .75 do — Yes

4 3X3 D .75 do No

5 3X3 D .75 do No

6 3X3 E .84 do. No

7 3X3 E .84 do No

Test 4

1 2X2 C 2 0. 59 Sprinkling 1 No

2 2X2 C .59 do. 1 No

3 2X2 D .75 do. 1 No

4 2X2 D .75 do. -- 1 No

5 2X2 E .84 do 1 No

6 2X2 E .84 do - l No

1 On account of its similarity in design to another extinguisher of larger capacity (extinguisher E), extinguisher B was tried only in the first test on P the 4- by 4-ft-area fire.

2 Due to the negative results obtained in the previous trials of the devices which were applied as hand grenades, extinguishers A and F were not tried in the tests on the 3- bv 3-ft and 2- by 2-ft-area fires.
2. Summary and Discussion of Results

The tests discussed in this paper showed that

the bulb-type devices when used as hand extinguishers were less effective than the 1-qt pumpgun carbon-tetrachloride extinguisher. In the

' first place, the capacity of the devices was, in

I general, too small to be practically effective and,

in the second place, the manner in which the

extinguishing liquid was applied made the devices

less effective than the pump-gun extinguisher for the same volume of liquid used.

The first test showed that none of the devices

put out a relatively simple test fire that the 1-qt

pump gun can usually extinguish easily. The

second test showed that to put out this test fire, more (in most cases much more) extinguishing

liquid was required. The third and fourth tests showed that even with test fires reduced in extent

and severity to a point where they could be extinguished easily by not more than one-half of the

full charge of a 1-qt pump-gun extinguisher, the

devices did not put out the test fires except in

the case of one of the units in one of three trials. With the bulb-type extinguishers, the liquid is not as thoroughly broken up and as readily vaporized as it is with the pump-gun extinguisher, from

which the liquid is forcibly projected in a rela- tively compact stream that changes to a fine spray

when it strikes objects in the fire. Furthermore,

when the liquid is applied by sprinkling from, a

container, it cannot be as effectively directed as it can be with the pump gun and, apparently, a considerable portion of the liquid serves to dilute the

burning gasoline rather than to cause the formation of a smothering gas blanket.

In the trials in which the test fire was not

extinguished, the flames were somewhat diminished during the application of the liquid, but the

fuel continued to burn with the production of

dense, acrid fumes in great volume. The tests were made in a room with a total volume of

approximately 90,000 ft3

. When 1 qt of extinguishing liquid was applied in the manner described above, it was found that shortly afterward

the fumes became so irritating that the operator was driven from the room, and they became so opaque that it was impossible to distinguish objects

at distances greater than 3 or 4 ft.

IV. Tests of Devices as Automatic

Extinguishers

The tests of the devices when used as automatic

extinguishers were conducted in one of the Bureau's fire-test buildings that contained a single room 29 ft long by 15 ft 3 in. wide by 10 ft 1 in. high. The walls were of brick and the floor and

ceiling, concrete. A fireproof partition was erected

across the building 13 ft from one- end to provide

a test space of 2,000 ft. 3 This enclosure contained

a single window 3 ft 4 in. wide by 4 ft 10 in. high,

with the bottom 3 ft from the floor. It was provided with a fireproof shutter, pivoted horizontally

at the center, which was so arranged that it could

be set at any given inclination to give the desired

ventilation. A tightly fitting door was constructed in the partition to give access to the

test space. This door was kept closed when the

tests were in progress. The space in the building

outside of the test space contained three wndows,

each 3 ft 4 in. by 4 ft 10 in. and one door, all of

which were kept open during the tests. During each test, the temperature of the air surrounding the extinguishers, as well as the temperature at various other points in the test space, was measured with thermocouples. The progress

of the test fires was observed by temperature

measurements taken at various points in the paths

of the flames.

1. Extinguishers A to F

According to the claims made for fire extinguishers A to F when presented for the tests, the

theory of operation was that should a fire occur

in the protected space the temperature would rise and the release mechanism would cause the discharge

of the carbon tetrachloride, whereupon the liquid

would vaporize and be carried by the convection

currents over the burning area to smother the fire with an oxygen-excluding blanket. According to

this theory, these devices were intended to place

a smothering gas blanket locally over a small area

of burning fuel and not to provide vapor sufficient

to dilute the atmosphere of the protected space to a point where combustion could no longer be possible because of the low oxygen content. This

theory excluded the use of the devices for fires in

ordinary combustible materials for which carbon

tetrachloride when locally applied is not considered

suitable, and the fires used in the tests were, therefore, confined to fires of flammable liquids (class B

fires). Because of the danger involved in the handling

of gasoline in a small room, oil rather than gasoline was used for the fuel. The oil was a mixture of

two parts of light engine oil with one part of kerosine. The fuel was contained in a pan located on

the floor. Fires of two sizes were used. The

larger of the two consisted of 2 gal of burning fuel in a pan 3 ft sq having 6-in. sides. For the second

fire, }i gal of fuel was used in a pan 2 ft sq having

1-in. sides. The number of extinguisher units recommended

by the makers was one for each 1,000 ft3 of space

protected. Accordingly, trials were first made

with two units in the 2,000-ft3 test space. Another series of trials was then made, in which the

number of units was doubled

3
(a) Results of Tests

(1) First test with two extinguisher units. Extinguisher C was chosen for this test. As shown

in table 1, this extinguisher had a capacity intermediate between that of the smallest and the

largest extinguishers in the gioup A to F. In

each trial, the two units were mounted 5}i ft above

the floor on the vertical center lines of the two

end walls of the test space. In every trial, the test fire pan was on the floor. Trials were first made with the pan at the center

of the test space (location a), then with the pan

next to one of the 13-ft walls directly under one

of the two extinguishers (location b), and finally

with the pan in a corner of the test space (location

c). The three locations of the pan are shown in

figure 2. Location b is also indicated in figure 3.

test were the following: Extinguisher A, one of

the two extinguishers having the smallest capacity L = (0.44 qt) of those tested; extinguisher F, having

the largest capacity (1.00 qt) ; and in one trial, 1 extinguisher E, having an intermediate capacity i , (0.84 qt).

WINDOW TEST- FIRE PAN

IN LOCATION C

EXTINGUISHER

EXTINGUISHER

CLOSED DOOR,

I TEST- FIRE PAN

IN LOCATION a

TEST- FIRE PAN

IN LOCATION b

-2-11

FlGTJRE 2. Plan for first series of trials of devices A to F

as automatic extinguishers. Two units used; 3-foot-square test-fire pan in trials 1 to 3; 2-foot-square pan

in trials 4 to 8.

During these trials, the shutter was tilted so that the ventilation through the window, both

above and below the shutter axis, was just enough

to permit the fuel in the test space to burn freely.

The results of the test are given in table 3. (2) Second test with jour extinguisher units. The second test, in which four rather than two

extinguisher units were used in each trial, was made

because of the negative results shown in the first test. The extinguishers chosen for the second

J!

Figure 3. Trial 5, first series of tests of devices A to F

as automatic extinguishers. The test pan was located directly beneath one of the extinguisher

units, as shown.

4
I

Table 3. Results of tests of devices A to F as automatic extinguishers

Test fire Extinguisher Was fire put out by the. extin- guisher?

Duration

of fire, extin- guishers present

Duration

Trial Fuel Area

of

test pan

Location

of

fire i

Designnation Capacity

Number

of units used

Number

of

Fuel

con- sumed

of fire, no

extinKind Quantity

units which

operated

guishers present

TEST 1

Oil. gal ft qt Percent min min

2 3X3 0 C 0. 59 2 2 No 100 14 14 .do 2 3X3 b C .59 2 2 No 100 14 14 .do_-_- 2 3X3 c c .59 2 2 No 100 15 14 .do Vl 2X2 a c .59 2 2 No 100 12 11 .do H 2X2 b c .59 2 1 Yes Less 0.7 11 than 10 .do H 2X2 b G .59 2 1 Yes Less .9 11 than 10 .do- M 2X2 c C .59 2

2 0 No 100 14 14 .do . H 2X2 c C .59 2 1 No 100 14 14

TEST 2

Oil..do.

.do.

.do.

.do.

2 3X3 a A 0. 44 4 4 No 100 14 13 2 3X3 a F 1.00 4 30 No 100 13 13 2 3X3 d A 0.44 4 4 No 100 15 13 2 3X3 d E .84 4 4 No 100 14 13 2 3X3 d F 1.00 4 <0 No 100 13 13

1 See figure 2 for test 1, and figure 4 for test 2.

2 The ambient temperature at 1 extinguisher was 205° to 210° F for \\<i min

and at the other extinguisher, 200° to 250° F for 2}i min.

3 The ambient temperature at the 4 extinguishers for 10 min during the test

was 370° to 415° F, 255° to 310° F, 355° to 410° F. and 245° to 285° F, respectively.

4 The ambient temperature at the 4 extinguishers for 10 min during the test was 230° to 300° F, 275° to 310° F, 315° to 355° F, and 2o0° to 300° F, respectively.

In each trial of the four samples under test, two

were mounted on the 15-ft 3-in. wall and two on

the partition opposite. The extinguishers were mounted at a height of 5}i ft from the floor and

were spaced 3 ft 10

shown in figure 4.

in. from the 13-ft walls, as

On account of the nature of the results obtained

in the first test, it was not considered necessary

in the second test to include all the test conditions

covered in the first. Therefore, only one of the

two test fires was used, the fire of 2 gal of oil and

kerosine in the 3-ft-sq pan. The trials were made

at location a with the pan on the floor at the

center of the test space, and at location d, with

the pan on the floor adjacent to one of the 13-ft walls. During the trials, the lower half of the window

in the 15-ft 3-in. wall was sealed off, and the shutter was tilted to leave an opening 40 by 20 in. in the upper half. Additional ventilation was provided for these tests by an opening approximately

40 by 20 in. in the fireproof partition opposite.

Both openings were above the midheight of the

test space, which was a condition recommended

by some of the makers of the devices tested. The

total area of the ventilating openings amounted to 4 percent of the wall area above the midplane of

the enclosed space. Trials with no extinguishers

present showed that these openings provided just

enough ventilation to permit the test fires to burn

freely until the fuel was consumed. The results of these trials are given in table 3.

Figure 4. Plan for second series of trials of devices A to F

as automatic extinguishers.

Four units used; 3-foot-square test-fire pan.

5
(b) Summary of Results

The tests of the devices in group A to F when

used as automatic extinguishers were conducted

in a room of 2,000-ft 3 capacity in which the ventilation was sufficient to permit the fires to burn

freely until all the fuel was consumed. The tests showed that when two extinguisher units (extinguisher C) were used the devices were not

effective in extinguishing or checking relatively

simple test fires located on the floor, except when

a small fire was located directly under one of the

extinguishers so that all its liquid was promptly

discharged into the pan of burning oil. When the

units were doubled in number and located so that no extinguisher was directly above the test fire, the devices (extinguishers A, E, and F) failed to extinguish or check the fires either when they were in the center of the room or against the wall. The thermal release mechanisms of some of the

units failed to operate as intended.

2. Extinguisher G

Extinguisher G was in the nature of an installed

system that operated on the principle of diluting

the atmosphere of the entire protected space to a

point where combustion would no longer be

possible because of the low oxygen content. The

claims for this device did not exclude fires in

ordinary freely burning materials, as was the case

for the extinguishers in group A to F. Hence,

in the tests of this extinguisher, trials were made

both on fires of freely burning material (class A

fires) and fires of flammable liquid (class B fires). The ventilating openings in the test space were

the two 40- by 20-in. windows used in the second

series of trials of extinguishers A to F. The number of extinguisher units specified by

the maker for extinguishing fires in ordinary freely

burning materials was one for every 1,000 ft3 of space protected and for putting out fires in

gasoline, oil, and like materials, one for every

750 ft 3

. Accordingly, in the trials on the wood

fires, two extinguishers were used and in the trials on the oil fires, three extinguishers. The units were suspended from the ceiling on the longitudinal center line of the test room and were equally

spaced, as shown in figures 5 and 6.

(a) Results of Tests

(1) First test with two extinguisher units on

class A fires. For the class A fires, one of the wood

fires frequently employed as "standard" for the

2%-gal soda-and-acid hand extinguisher was used.

The fuel for this fire consisted of 78 pine sticks 2 by 2 by 24 in. long. The sticks were arranged

in 13 layers. They were laid parallel and about

2 in. apart in each layer, were laid transversely to

layer. A cube was thus

24 in. on the side, with

ready combustion. The

supports Iji ft from the

by K gal of gasoline in a the cube. The results of

table 4.

Those of each layer

those of the preceding'

formed approximately

air channels to afford 1 cube was built on 1 floor and was ignited

pan placed 1 ft below

the test are given in

Figure 5. Plan for trials of automatic extinguisher G on' wood fire. Two extinguisher units used.

Figure 6. Plan for trials of automatic extinguisher G onf n oil fire on floor. Three extinguisher units used, 3-foot-square test-fire pan.

t
Table 4. Results of tests of automatic extinguisher G (capacity 1% qt)

Trial

Test fiie Extinguisher

AVas fire put out by the

extin- guishers?

Fuel con- sumed

Duration

of fire, extin- guishers present

I duration 2 of fire, no extin- guishers present

Fuel Area

of test pan

Location

of fire 1 Number

of units used

Number

of units which Kind operated Quantity

of oil

TEST 1

12 Wood 3... gal ft a

d

2

2 2 NoNo

Percent

100

100

min

2930

min

29 do 29

TEST 2

1 Oil... - 2 3X3 e 3 *2 No 100 13 13

2 do 3 3X3 d 3

5 3 Yes 40 4 22

3 Oil and wood 3 ..- 3 3X3 f 3 3 No 100 « 23 » 22

1 See figure 5 for test 1 and figures 6 and 7 for test 2.

2 For the wood fires, this was the time when the stack collapsed.

3 See description in text.

4 One unit failed to operate, although the ambient temperature at the extinguisher was about 400° F for 8 min.

6 One unit discharged cnly one-half its contents, although the ambient temperature at the extinguisher was 390° to 480° F for over 2 min.

6 Duration of oil fire. Wood continued to burn.

(2) Second test with three extinguisher units on

\class B fires. For the class B fires, 2 or 3 gal of

the mixture of two parts light engine oil and one

part kerosine were used in the 3-ft-sq pan having

l(5-in. sides. The results of these trials are given

in table 4. The third trial in the second test was made

because it appeared probable that, since the fire in the previous trial was located directly under

one of the extinguishers, the extinguishment of

the fire had been accomplished by a local gas

blanket rather than by dilution of the whole

atmosphere of the enclosed space. Hence, in the

third trial, the same test fire was used, but the

pan was placed beneath a wooden bench and about

18 in. off the floor, as shown in figure 7.

(b) Summary of Results

The tests of extinguisher G were conducted in

the same 2,000-ft3 room used for similar tests of

the smaller extinguishers. As in those trials, sufficient ventilation was provided to permit the

fires to burn freely so that they would not ex- tinguish themselves.

As indicated in table 4, in both of the trials with

a fire of freely burning material (class A fire) the

extinguisher, when one unit was used for each

1,000 ft3 of space, failed either to extinguish or check the fire. In the tests with the oil fires (class B fires), in

which one unit was used for each 667 ft3

, the

extinguisher failed to put out or check the test

fires in two of the trials and extinguished the fire

in one trial. In that trial, the fire was placed

directly beneath one of the units.

It appeared probable that, under the conditions

of the third trial, the fire was not extinguished by

dilution of the atmosphere of the enclosed space

but by a local blanketing effect.

~8~

^ EXTINGUISHER '

,4 FT SQUARE BENCH TOP

T

TEST-FIRE PAN

IN LOCATION f

ELEVATION

PLAN

Figure 7. Plan and elevation for trial of automatic ex- tinguisher G on oil fire in S-foot-square pan shielded by

wood bench.

Three extinguisher units used. 7
V. Conclusions

The tests indicated clearly that when hand

operated the bulb-type carbon-tetrachloride extinguisher, as represented by the samples tried, was distinctly less effective than the 1-qt pumpgun extinguisher, the smallest generally considered

acceptable, principally by reason of the manner

in which the liquid was applied.1 The bulb-type devices when employed as auto- matic extinguishers were not effective in protecting

the enclosed space. The seven devices were tested

in the number recommended by the manufacturer,

and six of them were also tried in double that

number.2

1 Other types of hand extinguishers recommended for use on fires in flam- mable liquids (class B fires) are described in the Manual of Fire-Loss Prevention of the Federal Fire Council and the NFPA Handbook of Fire Protection, Tenth Edition. The Manual may be purchased from the Superintendent

of Documents, Government Printing Office, Washington 25, D. C, at 30

cents a copy. The Handbook is published by the National Fire Protection

Association, 60 Batterymareh Street, Boston 10, Mass.

2 Water-sprinkler systems are commonly employed for the automatic protection of enclosed spaces in which the combustibles are of the usual freely burning solids. For flammable-liquid fires in enclosed spaces, automatically

operated systems employing carbon dioxide or foam are sometimes installed Washington, July 24, 1950.

o