Method of Determining Incombustibility [of Building Materials]

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PREFACE

B u i l d i n g r e s e a r c h o r g a n i z a t i o n s i n v a r i o u s p a r t s of t h e world have recognized t h e need f o r a d e q u a t e d e f i n i t i o n s f o r terms used i n b u i l d i n g codes, s p e c i f i c a t i o n s and o t h e r

r e g u l a t i o n s . When s p e c i f y i n g requirements f o r i n c o m b u s t i b i l i t y ,

a d e f i n i t i o n of t h e words "incombustiblen o r "combustible" may o n l y be g i v e n by r e f e r r i n g t o a s p e c i f i c t e s t method i n which c o n d i t i o n s of exposure a r e ' w e l l d e f i n e d ,

I n Canada, t h e r e e x i s t s a t p r e s e n t no t e s t method f o r i n c o m b u s t i b i l i t y s i n c e t h e withdrawal of C-EwSeA, S t a n d a r d S p e c i f i c a t i o n ~ 5 4 - 1 9 4 0 . The D i v i s i o n of B u i l d i n g Research h a s been aware of t h e s i t u a t i o n and, d u r i n g r e c e n t y e a r s , has co- o p e r a t e d c l o s e l y w i t h t h e Canadian S t a n d a r d s A s s o c i a t i o n i n t h e development of a new method, Close l i n k s w i t h o r g a n i z a t i o n s i n B r i t a i n and t h e U . 3 - A . have f a c i l i t a t e d t h i s work i n t h a t i n f o r m a t i o n on similar a c t i v i t i e s i n t h o s e c o u n t r i e s w a s

r e a d i l y a v a i l a b l e . Apart from t h e work of Setchltin and I n g b e r g , l i t t l e h a s been achieved towards t h e improvement of e x i s t i n g t e s t methods,

T h i s s y s t e m a t i c study of van E l t e r e n on t h e s u b j e c t i s t h e r e f o r e g r e a t l y a p p r e c i a t e d and w i l l c e r t a i n l y s e r v e as a g u i d e t o anyone concerned i n t h e developmefit o r t h e improvement

of t e s t s on c o m b u s t i b i l i t y . It i s w i t h t h i s i n mind t h a t t h i s t r a n s l a t i o n h a s been prepared as a p a r t of t h i s D i v i s i o n ' s p r e s e n t s t u d y of t h e problem.

The D i v i s i o n of Building Research r e c o r d s i t s t h a n k s t o

M r ,

H,A.G,

Nathan of t h e T r a n s l a t i o n s S e c t i o n of t h e N.R.C. f o r t r a n s l a t i n g t h i s paper.

O t t a w a ,

NATIONAL RESEARCH COUNCIL OF CANADA Technical Translation TT-694

Title: Method of determining incombustibility

[of

building materials]

(Methode voor de bepaling van onbrandbaarheid)

Author:

J.F.

van Elteren

Reference: Polytech. Tijdschrift, 9A (31-32):

644-650,

1954 Translator: H . 4 . G . Nathan, Translations Section,

N.B.

C.

Library

MZTHOD OF DETERMINING I N COMB'JSTIBILITY

[OF BUILDING MATERIALS ]

There h a s been a n i n c r e a s i n g demand t h a t t h e m a t e r i a l s used i n c e r t a i n s t r u c t u r e s of b u i l d i h g s , s t r u c t u r a l p a r t s and c o a t i n g s should p r e s e n t no f i r e hazard when exposed t o h i g h t e m p e r a t u r e s , and i f a f i r e does occur should not c o n t r i b u t e t o i t s i n t e n s i t y . I n o t h e r words, t h e m a t e r i a l s should b e

"

incombustible"

.

~ ~ I n c o m b u s t i b i l i t y n may only be d e f i n e d i n c o n j u n c t i o n w i t h a c a r e f u l l y arranged t e s t , such as t h a t d e s c r i b e d i n (1) B r i t i s h Standard No. 476: 1932

.

I n t h i s t e s t , a specimen of t h e m a t e r i a l

(50

mm. x 40 mm.

x

d mm., where d , t h e t h i c k n e s s , should n o t exceed 40 mm. ) Is placed i n a v e r t i c a l h e a t i n g t u b e , which i s h e a t e d t o 750°C. i n

1 1 / 2 hours. The m a t e r i z l i s not considered t o be incombustible

if t h e specimen flames o r produces g a s e s t h a t may b e i g n i t e d by a p i l o t flame o r i f t h e specimen glotvs more b r i g h t l y t h a n t h e w a l l s of t h e h e a t i n g tube.

I n t h e German S t a n d a r d s ( 2 ) a m a t e r i a l i s deemed incornbust- i b l e i f i t cannot be inflamed and i f it i s not reduced t o a s h e s i n t h e absence of a flame.

S e t c h k i n and Ingberg t e s t e d a l a r g e number of m a t e r i a l s i n t h e h e a t i n g a p p a r a t u s d e s c r i b e d i n t h e B r i t i s h Standard. The t e s t s were conducted according t o t h e B r i t i s h Standard and a l s o by a modified method i n which t h e a p p a r a t u s Is heated t o 750°C.

b e f o r e t h e sample i s introduced*.

They t e s t e d i n s u l a t i n g m a t e r i a l s , a c o u s t i c a l t i l e s and metal powders. The most s u r p r i s i n g r e s u l t was t h a t v i r t u a l l y

a l l t h e m a t e r i a l s r a t e d as lncolvbustible by t h e B r i t i s h method and containing upwards of 2 percent by weight of organlc carbon, flamed o r glowed on a p p l i c a t i o n of t h e modified method i n v o l v i n g i n i t i a l h e a t i n g of t h e furnace t o 750°C.

Setchkln and Ingberg determined t h e content of o r g a n i c carbon I n t h e sample i n v e s t i g a t e d . They used t h i s c o n t e n t a s

a

c r i t e r i o n of t h e amount of combustible c o n s t i t u e n t s of t h e samples.

Some of t h e i r r e s u l t s have been assembled i n Table I. The

s e l f - h e a t i n g , which h a s a l s o been l i s t e d , g i v e s t h e number of Centigrade degrees by which t h e temperature a t t h e c e n t r e of t h e m a t e r i a l t e s t e d i n c r e a s e s beyond t h a t of t h e f u r n a c e ,

On t h e s t r e n g t h of t h e i r t e s t s Setchkin and Ingberg con- clude t h a t i n c o m b u s t i b i l i t y depends, among o t h e r f a c t o r s , on t h e n a t u r e of t h e combustible components.and p o s s i b l y t h e i r d i s t r i b u t i o n i n t h e m a t e r i a l .

The r e s u l t s obtained from l a r g e s c a l e t e s t s , moreover, proved t o be i n agreement with t h e r e s u l t s obtained from t h e i n v e s t i g a t i o n by t h e modified method.

- -

*

Whilst t h e present a r t i c l e w a s b e i n g c o r r e c t e d , B r i t i s h Standard No.

476:

1953 w a s published. The modified method h a s now been adopted, and t h e o b s e r v a t i o n of t h e glow has been replaced by a measurement of t h e temperature. As a requirement of i n c o m b u s t i b i l i t y t h e specimen must n o t cause t h e furnace temperature t o be r a i s e d by more t h a n 50°C.

The furnace temperature i s defined as t h e temperature between t h e i n t e r i o r w a l l of t h e h e a t i n g t u b e and t h e specimen.

D e t a i l e d I n v e s t i ~ a t i o n Desirab-

I n t h e Netherlands a standard s h e e t h a s been prepared by Commis.sion 58 (Regulations Regarding t h e Fire-Resistance of B u i l d i n g s )

,

which included a d e f i n i t i o n of " i n c o m b u s t i b i l i t y n

a s w e l l a s a method f o r i t s determination. I n November 1953, T e n t a t i v e Sheet V1076 (Building M a t e r i a l s and S t r u c t u r e s of B u i l d i n g s , Determination of I n c o m b u s t i b i l i t y

,

Flammability, Flame Spread and Fire-Besistance) was published. I n t h e i n t r o - duction t o t h e d r a f t it i s pointed out t h a t t e s t s w i l l perhaps show the need f o r modifications i n t h e standard,

Therefore, it appeared p a r t i c u l a r l y d e s i r a b l e t o i n v e s t i g a t e t h e method of determining i n c o m b u s t i b i l i t y i n g r e a t e r d e t a i l .

Against t h e B r i t i s h method and t h a t modified by Setchkin and Ingberg, t h e o b j e c t i o n i s r a i s e d t h a t t h e comparison of t h e

i n t e n s i t y of t h e l i g h t r a d i a t e d from t h e glowing m a t e r i a l with t h a t r a d i a t e d from the wall of t h e almost completely closed h r n a c e i s not easy and by no means a c c u r a t e ,

Examination of t h e German standard immediately r e v e a l s i t s l a c k of d e f i n i t i o n .

I n t h e d r a f t f o r t h e t e n t a t i v e standard s h e e t the method t o be a p p l i e d and t h e term i n c o m b u s t i b i l i t y a r e described a s follows:

The furnace i s heated t o a temperature of 7 5 0 ~ C . The

temperature i s measured by means of a thermocouple whose junction

i s s i t u a t e d on t h e i n t e r i o r w a l l of t h e furnace a t t h e l e v e l of t h e c e n t r e of t h e specimen t o be introduced i n t o t h e furnace.

The t e s t specimen I s t h e n placed i n t h e f u r n a c e i n such a manner t h a t t h e l o n g i t u d i n a l a x e s of t h e specimen and f u r n a c e

c o i n c i d e ( t h e dimensions of t h e t e s t specimens a r e

60

x

40

x

40 mm.).

During t h e t e s t t h e specimen should be supported by a s t i r r u p of nichrome wire,

A m a t e r i a l I s considered t o be incombustible i f w h i l s t t h e sample i s i n t h e furnace:

( a ) no combustible g a s mixtures a r e produced d u r i n g t h e f i r s t

15

minutes;

( b ) t h e temperature a t t h e c e n t r e of t h e specimen does n o t i n c r e a s e by more t h a n 50°C, above t h e

fur-

nace temperature.

A m a t e r i a l i s considered combustible i f it does not s a t i s f y one o r both of t h e above c o n d i t i o n s .

I n t h i s connection, t e s t s were c a r r i e d o u t t o determine t o what e x t e n t t h e i n c r e a s e i n t h e temperature of t h e m a t e r i a l w i t h r e s p e c t t o t h a t o f t h e furnace provides a c r i t e r i o n of t h e in- c o m b u s t i b i l i t y and of t h e manner i n which t h e temperature i n t h e m a t e r i a l can b e s t be measured,

D e s i m of Furnace

F o r t h o p r e s e n t i n v e s t i g a t i o n a furnace i s used such as t h a t d e s c r i b e d i n t h e d r a f t f o r t h e t e n t a t i v e Dutch Standard Sheet 1076. It i s p r a c t i c a l l y t h e same a s t h a t used i n t h e B r i t i s h method, and a s k e t c h of it ' i s shown i n Fig. 1.

The f u r n a c e used h e r e d i f f e r s from t h a t d e s c r i b e d i n t h e B r i t i s h method by t h e f a c t t h a t i t s bottom i s c l o s e d by a f i r e -

b r i c k plug provided with n i n e p e r f o r a t i o n s ,

3

mm. i n diameter. The thermocouple with which t h e f u r n a c e temperature i s measured

i s p r o t e c t e d by a porcela.in tube. The l a t t e r h a s been placed

In a s e m i - c i r c u l a r r e c e s s i n t h e f u r n a c e w a l l .

The j u n c t i o n i s e x a c t l y o u t s i d e t h e tube and t h u s l i e s f l a t a g a i n s t t h e furnace wall.

The I n v e s t i r a t i o n

(a) pleasurement of t h e Temperature i n t h e T e s t Specimen S e t c h k i n and Ingberg measured t h e temperature a t t h e c e n t r e of t h e specimen, where t h e r e was a much g r e a t e r i n c r e a s e i n

temperature t h a n on t h e s u r f a c e .

T h i s i s evident f r o m t h e r e s u l t s assembled i n Table 11. S i n c e m a t e r i a l s whose

"

c o m b u s t i b i l i t y n has been e s t a b l i s h e d beyond doubt show p r a c t i c a l l y no d i f f e r e n c e i n temperature, o r only a n e g a t i v e one, when measurements a r e made on t h e s u r f a c e of t h e sample, t h i s method i s n o t s a t i s f a c t o r y and p r e f e r e n c e should t h e r e f o r e be given t o t h e method involving measurcnents a t t h e c e n t r e of t h e specimen.

An a t t e m p t w a s made t o determine how t h i s could b e s t b e achieved and t h e following methods were a p p l i e d .

1, From t h e mid-point of t h e t o p s u r f a c e of t h e sample a c y l i n d r i c a l opening, 6 mm. i n diameter, was bored t o t h e c e n t r e . A ceramic t u b e of 6 mm. o u t e r and

3

mm. i n n e r d i - ameter was placed i n t h i s opening, and t h e thermocouple was t h e n i n s e r t e d i n t h i s tube.

2 , The sample was provided w i t h an opening of t h e same s i z e a s i n method 1.

The thermocouple w i t h one of i t s w i r e s p r o t e t e d by i n s u l - a t i o n beads was i n s e r t e d i n t h i s opening.

3

From t h e mid-point of t h e t o p s u r f a c e , a n opening, 4.5 mm, i n d i a m e t e r , was bored v e r t i c a l l y through t h e e n t i r e s p e c i - men. The thermocouple was passed t h r c u g h t h i s opening i n such a way t h a t i t s j u n c t i o n w a s a t t h e l e v e l of t h e - e n t r e of t h e q e c i m e n , one wire emerging from t h e upper s u r f a c e and t h e o t h e r from t h e lower s u r f a c e ,

4, T h i s method i s i d e n t i c a l w i t h method

3

except t h a t t h e theruocou?le was p r o t e c t e d by a q u a r t z t u b e of 4.5 mm, o u t e r and

3

mm. i n n e r diameter.

5,

T h i s method d i f f e r s from method

3

only i n t h a t t h e opening was h o r i z o n t a l i n s t e a d of v e r t i c a l .

The r e s u l t s o b t a i n e d from t h e measurements have been

assemblsd i n Table 111. I n t h i s t a b l e , under "maximum i n c r e a s e i n O C . ' , t h e maximum number of c e n t i g m d e d e g r e e s i s g i v e n by

which t h e ternperature i n t h e specimen i n c r e a s e d above t h e f u r - n a c e temperature. T h i s i n c r e a s e i s a l s o g i v e n p e r p e r c e n t of

carbon p r e s e n t i n t h e specimen.

I n t h e c o u r s e of t h e s e t e s t s t h e t e m p e r a t u r e i n t h e specimen f i r s t a t t a i n s t h e f u r n a c e t e m p e r a t u r e a f t e r a c e r t a i n t i m e , t h e n

i t r i s e s above i t and, a f t e r r e a c h i n g a naximum, it drops a g a i n t o a t e m p e r a t u r e below t h a t of t h e f u r n a c e . S i n c e it had been a n t i c i p a t e d t h a t t h e h e a t from t h e b u r n i n g specimen w a s i n some way r e l a t e d t o t h e product of t h e i n c r e a s e i n t h e t e m p e r a t u r e of t h e specimen above t h a t of t h e f u r n a c e and t h e time r e q u i r e d f o r t h i s i n c r e a s e , t h e product of t h e nominal degree and minute

v a l u e s i s a l s o l i s t e d i n t h e t a b l e . T h i s product has been computed p e r gram of weight of t h e specimen and p e r p e r c e n t of carbon, and i s given a s t h e f a c t o r !J.

The curves d e p i c t i n g t h e course of two d i f f e r e n t t e s t s have been p l o t t e d i n Fig. 2 _and

3.

The products of t h e nominal degree and minute v a l u e s a r e i n agreement w i t h t h e a r e a enclosed by t h e curves.

It i s e v i d e n t from t h e v a l u e s given i n T a b l e s I11 and

IV

t h a t :

1, The f i r s t method of measurement g i v e s t h e lowest r e s u l t s . T h i s a p p l i e s p a r t i c u l a r l y t o t h e specimens c o n t a i n i n g

3%

carbon; i n o t h e r words, t h e s p e c i f i c h e a t of t h e ceramic t u b e and t h e h e a t l o s s e s along t h e t u b e play a n important r o l e , which becomes more marked a s l e s s h e a t i s g e n e r a t e d by t h e sample. However, t h e s e a r e t h e samples f o r which t h e d e t e r m i n a t i o n has been intended.

2 , Regarding t h e second method ( i n v o l v i n g t h e u s e o f i n s u l a t i n g beads) t h e same o b j e c t i o n a p p l i e s , though t o a s m a l l e r

e x t e n t .

3

Much h i g h e r r e s u l t s a r e obtained from methods

3

and 4 t h a n from 1 and 2. They show agreement w i t h i n t h e l i m i t s of experimental e r r o r . The average maximum i n c r e a s e s were

98

and 104 i n t h e c a s e of

3%

carbon and 148 and 140 f o r

5%

carbon, t h e averages f o r f a c t o r W being 4,5 and 4,5 i n t h e f i r s t c a s e and 6.0 and 5.9 i n t h e second,

4, The r e s u l t s obtained from method

5

a r s s l i g h t l y l o n e r t h a n t h o s e from methods

3

and 4. The advantage of t h i s method i s t h e p r o t e c t i o n of t h e coupling w i r e s by q u a r t z t u b e s , which c o n s i d e r a b l y i n c r e a s e t h e l i f e of t h e couple. Without t h i s i n s u l a t i o n t h e l a t t e r would have t o be r e p l a c e d a f t e r each t e s t .

E f f e c t of>he Di~nensions of t h e Test Speclrnea

The f o u r t h method of measurement described above was used f o r t h e determinations reported below. The r e s u l t s have been assembled i n Table I V .

It appears t h a t t h e ditnensions of t h e t e s t specimens g r e a t l y a f f e c t t h e temperature increase. The smaller t h e samples, t h e

s l i g h t e r the i n c r e a s s w i l l be. However, t h e dimensilms do not a f f e c t t h e f a c t o r W e

With respect t o t h e heat of combustion i t should be noted t h a t i f t h e samples contain combustible matter o t h e r than carbon, i t s percentage ( i n t h e f a c t o r I d ) i s converted t o a corresponding percentage of carbon,

( c ) E f f e c t of Combixstilnn Heat and Comnosition of t h e Test Specimens

The t e s t s described below were c a r r i e d out f o r t h e purpose

of determining whether r e l a t i o n s h i p s e x i s t between t h e n a t u r e

and t h e amount of t h e combustible c o n s t i t u e n t s i n t h e case of t h e combustion heat of t h e specimens, and between t h e n a t u r e of t h e o t h e r c o n s t i t u e n t s and t h e temperature i n c r e a s e i n t h e case of t h e f a c t o r W e

The r e s ~ l l t s a r e l i s t e d i n Tables V , V I and V I I .

The values given i n t h e s e t a b l e s f o r t h e temperature i n c r e a s e a r e shown diagrammatically i n Fig. 4,

The percentages of carbon present i n t h e samples, o r , with r e s p e c t t o t h e combustion h e a t , t h e corresponding percentages of

c a s e i n , have been p l o t t e d on t h e a b s c i s s a .

Fig. 4 shows t h a t a f t e r a n i n i t i a l l y l i n e a r i n c r e a s e t h e subsequent e f f e c t on t h e temperature i n c r e a s e i s s l i g h t , o r

n o n - e x i s t e n t , a s t h e percentage of combustible material. increases, I n o t h e r words, t h e temperature i n c r e a s e p e r p e r c e n t of com-

b u s t i b l e m a t e r i a l i s c o n s t a n t f o r low percentages and t h e n diminishes g r a d u a l l y .

It i s remarkable t h a t t h e composition of t h e t e s t m a t e r i a l a f f e c t s t h e temperature i n c r e a s e . This a p p l i e s t o b o t h t h e

cornbustible m a t e r i a l and t h e f i l l e r ( c . f . Table V I I I )

.

I n Fig.

5

t h e v a l u e s of Tables V , V I and V I I a r e shorm i n t h e same manner as i n Fig. 4 , bt with t h e f a c t o r W a s t h e o r d i n a t e .

It had been a n t i c i p a t e d t h a t f a c t o r W would b e c o n s t a n t , i.e., t h a t t h e temperature-time product would be a d i r e c t c r i t e r - i o n of t h e combustion h e a t , b u t t h i s d i d not prove c o r r e c t .

The e x p e r i a e n t a l method t h u s provides no 2 i c t u r e of t h e amount of c a l o r i e s r e l e a s e d by t h e combustion.

However, t h e d i s t i n c t e f f e c t of t h e n a t u r e of b o t h t h e f i l l e r and t h e combustible c o n s t i t u e n t becomes apparent.

S i n c e t h e primary purpose of t h e d e t e r m i n a t i o n i s t o d i s -

t i n g u i s h between "combustible" and " incombustible" m s t e r i a l s , and

t h e d i v i s i o n l i e s a t low percentages of combustible m a t e r i a l , t h e i n v e s t i g a t i o n was continued with t h e t e s t specimens having a number of o t h e r compositions, but only a t low percentages.

The r e s u l t s obtained from t h e s e t e s t s have been assembled i n Table I X .

The val~xes of Table I X , including t h e r e s u l t s of some of t h e preceding t e s t s , a r e shown diagrammatically i n Fig.

6

and

7.

The e a r l i e r conclusions regarding temperature i n c r e a s e and f a c t o r W a r e t h u s conflmed.

There i s a marked e f f e c t of t h e combustible m a t e r i a l and f l l l e r on t h e temperature increase. The f a c t o r W i s a l s o a f f e c t - ed, but does not give any i n d i c a t i o n of t h e combustion heat.

An acceptable explanation f o r t h e marked e f f e c t of t h e n a t u r e of t h e combustible m a t e r i a l cannot be deduced from the present t e s t s . The amount of oxygen required f o r t h e combustion of 1 gm. of c a s e i n i s v i r t u a l l y equal t o t h e amount of oxygen consumed by

1 gm. of carbon. Hence t h e g r e a t d i f f e r e n c e cannot be due t o t h i s , nor can i t be a t t r i b u t e d t o t h e formation of water during t h e combustion. This should apply equally t o both wood and c a s e i n . However, the r e s u l t s f o r gypsum-sawdust and gypsum- c a s e i n a r e divergent.

I n cases where a temperature i n c r e a s e of 50°C, t a k e s p l a c e , t h e percentage of combustible m a t e r i a l ( c a l c u l a t e d a s carbon) v a r i e s from

1.3

t o 4.2$, v7'-'?ereas f o r 2% combustible m a t e r i a l t h e f a c t o r W v a r i e s from

0.3

t o 4.1,

The e f f e c t of t h e combustible m s t e r i a l i s much g r e a t e r than t h a t o f t h e f i l l e r . The curves f o r gypsum-sawdust and gypsurn- aica-sawdust l i e c l o s e t o one another and so do those f o r gypsum- carbon and gypsum-mica-carbon. I n both cases t h e temperature i n c r e a s e of gypsum samples i s s l i g h t l y higher than t h a t f o r the corresponding gypsum-mica samples.

F i n a l l y , mention should be made of t h e time during which t h e temperature i n t h e sample i s above t h a t of t h e furnace.

Fig. 8 g i v e s a number of t h e s e time periods.

It i s evident t h a t t h e time i n c r e a s e s a s t h e percentage of combustible m a t e r i a l i n c r e a s e s . The i n c r e a s e i s l i n e a r and ap- proximately t h e same f o r t h e d i f f e r e n t m a t e r i a l s . Only t h e r e s l a l t s of t h e gypsum-casein samples show g r e a t divergence.

( d ) The Formation of Combustible Gas Mixtures

I n t h e d r a f t f o r -Lha t e n t a t i v e standard s h e e t t h e f i r s t requirement of i n c o m b u s t i b i l i t y i s t h a t during t h e f i r s t

15

minutes of the t e s t no combustible g a s mixtures can form.

I n o r d e r t o check t h i s a p i l o t flame wks burning r i g h t above t h e furnace.

No combustible gas mixture was produced i n any of t h e t e s t s described above.

Conclusion Regarding t h e D r a f t of t h e T e n t a t i v e Standard Sheet V1.076

With r e s p e c t t o t h e spreading of f i r e t h e h e a t r a d i a t i o n i s of p r i n a r y importance. The l a t t e r i s a f u n c t i o n of t h e tem- p e r a t u r e . A s i s evident from t h e above s t a t e m e n t s preference should be given t o t h e f o u r t h method o f measurement i n t h e de- t e r m i n a t i o n of temperature.

For m a t e r i a l s composed of t h e same c o n s t i t u e n t s t h e tem- p e r a t u r e i n c r e a s e a t t h e c e n t r e of t h e t e s t specimen i s d i r e c t l y p r o p o r t i o n a l t o t h e percentage of combustible m a t e r i a l , but t h i s

i n c r e a s e i s not t h e same f o r m a t e r i a l s with t h e same combustion

heat.

Therefore, i t i s b e t t e r t o measure t h e temperature i n c r e a s e than t o determine t h e combustion h e a t .

References

1. B r i t i s h Standard I n s t i t u t i o n . D e f i n i t i o n s f o r c o m b u s t i b i l i t y of building m a t e r i a l s . B r i t i s h Standard No. 476:

1932.

2. Deutsche Normen

D.I.N.

4102, 1940.

3.

Setchkin,

N.

and Ingberg, S. Test c r i t e r i o n f o r an

-15-

Table I Composition of t e s t specimen Gypsum

+

l o $

c a s e i n n n

+

_20% n

₊

_15%

_carbon 11

+

30%

_sawdust

t i l e s None None None

Material t e s t e d Asbestos n II II Acoustical Self-heat ing ( O C , ) 3rganic carbon

%

l e 4 2 , O

3e5

4e5 3 r i t i s h Method 70 62 162 285 I g n i t i o n Difference i n temperature ( O C , ) of furnace and Modified Method None None

55

1 2 2 B r i t i s h Method None None None None Centre of specimen

+ l o o

+120 +110 + 75 Modified T,let'tlod None None Flame & glow Flame & glow Surface of specimen

-30

-30

0

+15

Table

117;

--

Test Specimen Measurements

Tenp

.

Max. Tenp

.

Composition Dimensions Wt. in gm. m e a s inc

.

_{inc. per} i n cm. acc. t o _in

O C * % carbon W

Table

IV

-

T e s t

Specimen

Me-

surements

Composition

i n

%

Gypsum

55,

Vermiculite

25,

Casein 20 n n Gypsum

95,

Carbon 5

n n Dimensions

i n

cm,

6-lk-4

6-3-3

6-2-2

6 - b 4

6-3- 3

6-2-2 W t

,

i n

-0

48

26

13

'XI0

64

27

Max.

inc

i n

OC. 200

160

130

115

98 80 Temp.

inc.

per

%

carbon

13

11

9

-

W 2.8

3.1

2.3

23

1

5.7

20

16

5 . 2

5.2

Table

V

Test Specimen Measurements

Dimen- Wt, Max. Temp. Time (min.) _{during which} sions in inc. inc* per

Composition in W t.amp, is gm in O C . $ carbon above fur-

carbon 6-4-4 9 . 1 4 2 145 r 2 s 13? IJO

Table

V1:

T e s t Specimen ~ e a s u r e m e n t s

Dimen- Temp. Tima (rnin.)

Wt. Max

.

w

d u r i n g which Composition s i o n e _{i n i n c .} i n c

.

_{tenp. i s} i n om. p e r

%

above f u r - Rm. i n F. _{c a r b o n nnca temp.} Table V I I -- - T e s t Specimen Measurements

Dimen- Temp. Time (min.)

Composition _{a ion6} V t . MAX. i n c . d u r i n g which

i n inc. p a r $ W tsnp. i s

i n % i n cm.

-20-

Table

VIII

Temperature Gypsum Gypsum-Mica Gypsum

i n c r e a s e

11.3%

c a s e i n ,

1, e.

,

10% carbon

Table

IX

Test Specimen Measurements

Max.. inc. i n OC, 28

5 0

W t . in.. g m , 119 118 Cornposit ion gypsum-2 sawdust

"

-2-7 t~ 1 4 24 7 8 17

-

7

16 Dimen- s i o n 111 cm. 6-4-4

"

65 gypsum,

33

mica, 2 sawdust 64 gypsum, 32 mica, 4 sawdust 63 gypsum,

31

mica,

6

sawdust gypsum-2 cork I' - 4 " 4.1 2.5 1.1 2.7 be3

-

0.9

3-3

Time ( I n min,) during which temp, i n speci-

men

i s above. furnace temp, I 9 Temp,

i n c .

p e r

%

carbon

-

40 I W

-

2 04

thermocouples

test specimen heating element

temperatur adjustment Fig. 1 I -. .-

-

. . . ,

-.

. 4 gypsuml - - i _{. .} '3% carbon

' /

. . . , , . . ,

.

1.

.

, , . . . . , , -*-.-.--

--...

-..-

.

A

-

- - . . .

5 10 ( 5 i G .Y; I: 4', 4:. ',G -,: hri c , ~ , !'I

-

tima in min. .

.

. , a s , gypsum-=ice -- - . s a w d u s t ' ' c~ , . . I . , . --time in min. Fig. 2 _Fig.

₃

-

% carbon F1g. 4.

-

g ~ p s - c a s e ~ n ~ Fig.

5

caseine =

casein

gips =

gypsum

houtrneel

=

sawdust

koolstof

f =

carbon

kurk

=

cork

mica

= mica -% carbon ~ i g . 6

, , I

.

. .

.

. . - .

.

.

4 , .i -1 &iJ I ' , 6 7 -% c a r h a n

Fig.

7 t i . . .-.A ---.. ..- It; ? ' '$4 7 . 4 Fig. 8 c a s e l n e = c a s e i n g i p s = gypsum houtmeel = sawdust k o o l s t o f f = carbon k u r k = c o r k mica = mlca