Dry Chemical Extinguishing Agents

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Technical Note (National Research Council of Canada. Division of Building Research), 1953-09-28

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Sumi, K.

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DIVISION OF BUILDING RESEARCH

NATIONAL RESEARCH COUNCIL OF CANADA

'fE

C

1HIN II CAlL

NOTJE

No.

158

NOT FOR PUBLICATION FOR INTERNAL USE

PREPARED BY K. Sum1 CHECKED BY . APPROVED BY

PREPARED FOR Inquiry Reply

SUBJECT

Dry Chemical Extinguishing Agents

As a result of operational troubles that the Royal Canadian Air Force experienced in the field of dry chemical extinguishment,

the R.C.A.F. carried out a service investigation. This investigation

disclosed the presence of foreign materials such as small pieces of paper and hard particles which seemed like gravel in the dry chemical.

On June

15, 1953,

Squadron Leader W.A. McCallum of the

R.C.A.F. contacted the Fire Research Section, Division of Building

Research, National Research Council, concerning this problem. The

Fire Research Section was requested to carry out ｬ｡｢ｯｲｾｴｯｲｹ tests

on a number 0f dry chemical powders, samples of which were sent to the

Fire Research Section on July

31, 1953.

These tests were to determine

the characteristics of the samples supplied and in particular the following:

(1) Chemical composition

(2) Particle sizo distribution

(3) Bulk dens ity .

(4) Abrasi.e quality

'P./ ..

,'- ,

.\

-2-The chemical composition was analysed by the Division

of Applied Chemistry, National Research Council. All the other

tests were carried out by the Fire Research Section. In addition

to the above tests, the Fire Research Section carried out the following:

(6) Free flowing characteristics

(7) Moisture content

(8)

Elevated temperature characteristics

(9) Low temperature characteristics

The following sample numbers were given to the dry

｣ｨ･ｭｩｾ｡ｬ samples and reagent grade sodium bicarbonate which was

used for comparison. sample No. 1 2 3 I ｾＮ

5

6

7 Manufaoturer Safety First Co.

ｾｭ･ｲｩ｣｡ｮＭｌ｡ France-Foamite Corp. Ansul Chemical Co.

Fyr-Fyter Co.

The General Fireguard Corp. CO-TWOFlre Equipment Co.

Walter Kidde

&

Co.

ｾＢ ;' • L '.J , ｾｾ［ .,.:'Ｎｾｾ . I -4 . . . .t '4_ ,... # rf", ...,," .*',r J, , .:. )ｾ-,' ＧＺｾＺＧ . ,., • .J. i. .. l.' '.1; .,",'. .' 4 ｾ i!...J , , ." ,..;,-' or","f f"'l,.t (.- , " I :.r ...ｾ 11f i: 2.oJi j ..) . ｾ ...' .... ｾＮ (f' .ｾ , ｾ I)j J: 'ｾ ,".ＨＧＭＮＬｾ ｾＮＧ j _._j ｾＢ to) ｾＱ ｾｾＮＺＺｦＢＢＧＺＺｊ｜ｴ \.J-'1'!;, ｾ ..I ＬＮＧｾｊＢ .·;.\'1ｾＮＨ i't'i .......! .", : . , t' ' :J • '.J .. t..! ＮＬｾＩＮｾ

-

ｾ - -i' .P. ., ,., < .. , .. I • i.ｾＺＬｴ (,.._ _" Ｌｾ J...:' ,.. . I i ' ,')'J,... Ｎｾ • tｾＧ ..,

,-,.'

, f,) ,:,."t.'

e

e

e

"

ANALYSIS OF ｐｏｾｭｅｒ SUPPLIED FOR FILLING DRY POWDER FIRE EXTINGUISHERS

ｾ i BALANCE CONSISTS OF ! TRICALCIUM I. ｓｔｅａｒＧａＧ［Ｇ［［［［Ｇｲｾｅｾｩ ＧＺ［ＧＺ［ＧｾＧＧＺＺＧＧＺ［［ＧＧＧＧ［［Ｇｪ］ＭＭＭＭＭＭｩ

----I:

rE

SODIUM

ｩｾｕｍｉ

lSi

,--- I

r

n - -

ＺｾＮ

_ _ _ _ n_ATE

I

I

i

I ｾｾ STARCH SILICA TALC

I

Zinc

..;

I

Alfco

I

₂

I

₉₇

ＮＳｾ

I absent absent present absent

I

•

Anaul

I

₃

I

_97.7%

present Magnesium

I

absent absent absent

i

I

CO Two 6

I

93.6%

absent Magnesium absent absent presentl

I

Fyr Fyter

₄

I

_97.1%

present Magnesium absent absent absent

General

I

Magnesium

I

Fireguard

₅

_97.7%

present absent absent

i

absent

I

_I

Kidde ₇

_97.0%

present

I

Barium

I

present, absent

!

absent

!

I

.

I

:

Safety First 1

!

I ＹＰＮＷｾ

I

_{pre sent}

l

I _{Magnesium absent absent}

I

I

I

present!

I I

.

I i I , i

• }.

..

.'

- l

,.

1 ,

e

Ｍｾ

2. Particle size distribution

A. Apparatus

A nRo-Tap" sieve shaker with United States

Standard Number 40, 100, 200 and 325 sieves was used for

particle size determination. The shaker operated

with a circular motion at ＲＵＰｾＱＰ r.p.m. and with a

tapping ｡｣ｴｩｯｾ of lSO±5 strokes per minute.

B. ProG8dure

(1) The ｾｩＸｶ･ｳ were assembled in the order of

decreasing size with the largest sieve on top and a pan at the bottom.

(2) A 50-gram sample was weighed to the nearest

0.1 gram and was placed on the 40-mesh sieve of the asae::nbly.

(3)

The siove assembly was inserted in the shaker

and the machine was operated for 15 minutes.

(11.J The amount of the sample retained on eacb sieve

and the pan was weighed and the values ｯ｢ｴ｡ｩｭｾ､

·lvere converted into percentages retained.

(5 ) Tile procedure nas repeated for the other samples.

c.

Results

kLQ

Percentage retained

Sample No. 100 200 325 pan

1 0 0 0 8.1 91.9 2 0 0.2 1.6 43.5 ＵｾＮＷ 3 0 0 2.0 20.0 7 .0

ｾ

0 0 0.5 16.5 83.0 0 0 0·4 16.0 83.6 6 0 0 1.0 60.4 38.6 7 0 0 12.3 33.0 54.7 8 0 0.3 20.8 37.4 41.5

-5-3. Bulk Density

A. Procedure

(1) A tared 50-mI. beaker was carefully filled with

a sample making sure that the content was not disturbed in order to obtain the approximate minimum bulk density.

(2) The content was levelled off at the brim of the

beaker by using a spatula and the beaker with its content was weighed.

(3) The content was next made more compact by lifting

the beaker and tapping it on the work bench.

': ｾｾＩ After adding more dry chemical to the beaker and

making the content more compact the content

was again Jevelled off at the brim of the beaker and weighed.

(5) The prodedure was repeated for all the other

samplec:: •

(6) The volume of the beaker was next determined ｢ｾ

putting in a measurad quantity of water through a burette to the brim of the beaker.

B. Hesults

Sample No. Bulk density (gm./cc)

1 1.0 - 1.3 2 1.0 - 1.4 3 1.0 - 1.4

ｾ

1.0 - 1.4 1.1 - 1.4 6 1.0 - 1.3 7 1.1 - 1.4 8 0.8 - 1.1

-6-4.

Abrasive quality

A. Procedure

(1) One gram of the sample was placed between glass

microscope slides.

(2) The slides were rubbed together between the ｦｩｮ･ｾｲｳ

for three minutes. Light pressure was exerted.

(3) The proc.edure was repeated for all the other

samples.

(4) The slides used with each of the dry chemicals

were compared to those used with sodium bicarbonate. B. Res'..llts

None of the scratches produced on glass microscope slides by the dry chemical samples was more severe than the scratches made using sodium bicarbonate.

5. Water repellency

A. Procedure

(1) A 50-gram sample was weighed in a tared low

form 250-ml. beaker.

(2) 50 mI. of distilled water at 70!5°F. was

carefully poured on to the sample so that the sample was not agitated.

(3) The sample was allowed to stand for two minutes

and then the contents of the beaker were poured out f

(4) The beaker was dried in an oven at 60°C. (140°F.)

for 30 minutes.

(5) After cooling, the beaker was reweighed and

the percentage of the sample remaining in the beaker was determined.

5.

Water repellency (cont'd.) B. Results Sample No. 1 2 ') ,.J

b.

5

(:; 'I I 8

-7-Percentage retained in beaker

0,4

ＱｾＰ

0.8

ＱｾＰ 0 ..

4-0.6

0.4

38.2

6.

Free fl')wing characterist lcs

A. Proced.ure

(1) A visual Ｙａ｡ｭｩｮ｡ｴｾ｟ｯｮ \;Ta.J mad9 to determine if

the samples of dry chemical were free ｦｬｯｷｩｮｧｾ

All seven samples of dry chemical appeared

to be free flowing when examined by visual observation.

The reagent grade sodium bicarbonate was not free flowlng.

7.

Moisture concent

A. Procedure

(1) Samples of approximately

So

grams were weighed

in l20-ml. tared porcelain evaporating dishes.

(2) The dishes containing the samples were placed

in desiccators using

96%

Chemical Pure sulphuric

acid as a drying agent.

(3) After leaving in the ､･ｳｩ｣｣｡ｴｯｾｳ for

48

hours

the dishes were reweighed to determine the loss of moisture.

..

8-7. Moisture content (cont'd.)

B. Results sample No. 1 2 3

1+

::

A 7 8

Percentage moisture content 0.013 0.015 0.022 0.016 0.018 0.030 0.032 0.004

8.

Elevated temperature characteristics

A. Procedure

(1) About 100 grams of each sample were placed in

300-ml. tall form beak0rs.

(2) The sanples were heated :n an oven at 600

Co (1400Ff)

for seven days and then cooled ｦｯｾ three days at

ＷＰｾＵﾰｆｯ and ＵＵｾＵＥ relative humidity.

(3) The samples were next examined for' evidence of

cakingc Any lumps present were dropped from a

heidht of 4 inches onto a smcoth, hard surface to see if they were friable.

B. Results

None of the dry chemical samples showed caking. Any lumps present wet'e found to be friable when dropped

from a height of

4

inches onto a smooth, hard

surface. In contrast to the dry chemical samples,

reagent grade sodium bicarbonate showed caking and

the lumps formed did not ｢ｲ･ｾｫ completely but were

..

-9-9, Low ｴ･ｭｰ･ｲ｡ｴＮｵｾＺＬｾ cnaracteristics

A. Procedure

(1) Approximately 20 grams of each sample were

placed in stoppered test tubes.

(2) The test tubes were placed in a Bowser deep

freeze unit and the temperature was lowered to

-65°P.

(3)

The samples were allowed to remain at

-65°F.

for

one hour.

(4) The test tubes were then removed and inverted

without removing the stopper. Visual examination

was made to determine if the ｳ｡ｭｾｬ･ｳ were free

flowing.

(5) The samples were next examined for evidence of

caking. Any lumps present were dropped from a

height of four inches onto a smooth, hard surface to see if they were friable.

P. Results

All the samples had a tendency to stick to the

test tubes. No lumps remained when dropped from a

heigl1.t of four inches except in the ce.se of reagent

grade sodium bicarbonate. The sa.mples of dry chemical