A.S.T.M. Combustibility Tests

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A.S.T.M. Combustibility Tests Shorter, G. W.; Sumi, K.

A , S .TOM. C O M B U S T I B I L I T Y T E S T S

by G.W, S h o r t e r anC! K. S c m f

P--c j e c t . A-C) f o r S ; l b c e m m f t t ; e e V o f A.S,T.M, C.1~,7r,;zu4;ee

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-.-.---.. -2 R e s e a r s k R e p a r 5 No,

6

o f t h e D i v i s f on o f Buf l d f n g R e s e a r c h

A,S,ToM, C o m b u s t i b i l i t y T e s t s

-

by G,W, S h o r t e r and K. Sumf

The purpose of t h e A.S,T.M. C o m b u s t i b i l f t y T e s t s , Pro ~ e c t A-9, performed by t h e P f r e R e s e a r c h S e c t f o n , Divf s i c n c f B u i l d i n g Research, N a t i o n a l R e s e a r c h C o u n e f l , was t o a s s i s t w i t h t h e s t u d i e s u n d e r t a k e n by S u b c o m i t t e e V of A,S,ToM,

Committee E-5 c o n c e r n i n g t h e d e f i n i t i o n of " c o m b u s t i b i l i t y " . The d e f f n i t i o n and method of t e s t a p p l y t o b u f i d f n g materf 613

i n i t i a l l y i n t h e s o l i d s t a t e . They do n o t apply t o f f n e P y df vfded a a i i d m a t e r i a l s .

G e n e r a l D i s c u s s i o n

-

A meetfng of Subcommittee V of A,S,T,M, Committee

E-5

on f i r e t e s t s of m a t e r i a l s and c o n s t r u c t i o n was h e l d on February 28, 1 9 5 0 ~ a t P i t t s b u r g w i t h P r o f , J,R, S h a n ~ of t h e Ohio S t a t e U n i v e r s i t y a s Chairman. M r . D , T , Hewson of t h e F i r e Hazard T e s t i n g L a b o r a t o r y was p r e s e n t a s r e p r e s e n t a t i v e of t h e 1Jatfonal Hesearch Council. R e p o r t s o f t e s t s i n accordance w i t h t h e a p p a r a t u s and p r o c e d u r e s of "Proposed T e n t a t i v e T e s t f o r

I n c o m b u s t i b i l i t y o f S o l i d M a t e r i a l s " which appeared a s an appendix too t h e minutes of t h e meeting of March

4,

1948, were r e a d a t t h i s a e e t f n g , I n a d d i t i o n , t h e t e s t s t h a t had been made by M r . N,P.

S a t c h k i n of t h e N a t i o n a l Bureau of S t a n d a r d s were b r o u g h t t o t h e a t t e n t i o n of t h e Subcor~lmittee.

The Chairman p l a c e d b e f o r e t h e Subconmittee t h e q u e s t i o n a s t o whether t h e p r o c e d u r e i n d e v e l o p i n g a d e f i n i t i o n f o r

" i n c o m b u s t i b i l i t y " should be changed. A f t e r d l s c u s s f on, i t was d e c i d e d t h a t a Z a f i n i t f o n be adopted w i t h b l a n k s f o r c e r t a i n s p e c i f i e d l f m i t s , which s h o u l d be f i l l e d i n when s u f f i c i e n t t e s t

d a t a were a v a i l a b l e .

The def i n f t i o n proposed was, "Any n a t e r f a 1 s h a l l be c o n s i d e r e d t o be COMBUSTIBLE which when t e s t e d a c c o r d i n g t o t h e

?Yropes3d T e n t a t i v e Method o f T e s t f o r I n c o m b u s t i b i l i t y of

S c l i d I J ~ a t e r f a l s ~ , which appeared i n t h e Minutes of S u b c o m i t t e e V

of A,S,T,M, Committe2

E-5

of March

4,

1948, a s amended, shows e v i d e n c e of b u r n i n g a f t e r . . . , s e c o n d s from t h e s t a r t of t h e t e s t ,

0;. which a t any time d u r i n g t h e t e s t shows an I n t e r n a l t e m p e r a t u r e T 3 of t h e t e s t specimen g r e a t e r than..

.

. p e r c e n t of t h e f u r n a c e t e a p s r a t u r e T ~ " .

A n Advisory Study Group c o n s i s t i n g of t h e f 01;owing members was formed t o devalop t h e s e d a t a :

J,R, Shank, Ohio S t a t e U n i v e r s i t y (Chafrman)

D O T , Hewson, National Research Councfl

N , D o i . l i t c h e l l , N a t i o n a l Bureau of S t a n d a r d s

C.E. Abbey, Gypsum A s s o c i a t i o n

The f o l l o w i n g s u g g e s t i o n s f o r t h e o p e r a t i o n o f t h i s

A d v i s o r y S t u d y Group were made:

( a ) The Chairman w i l l a s k a l l members o f t h e Subeorirnfttea a n d o t h e r s i n t e r e s t e d t o s u g g e s t m a t e r f a l v w h f c h i n t h e i r o p i n i o n s h o u l d b e i n c l u d e d i n t h e d e v e l o p m s n t o f t h e s e d a t a . W i t h t h e s e s u g g e s t i o n s s h o u l d csme c l e a r l y d e f i n e d i n f o r m a t i o n c o n c e r n i n g e a c h a a t e r l a l s u g g e s t e d , t o g e t h e r w i t h i n f o r m a t i o n a s k h e r e t h e m a t e r i a l may b e o b t a i n e d ; ( b ) The Groap w i l l m e z t t o d e t e r m i n e , f r c m t h e s e a u g g e u t f o n s , w h i c h m a t e r i a l s s h a l l b e o b t a i n e d a n d i n c l u d e d i n t h e s e r i e s , t o n a p o u t t h e g e n e r a l p l a n o f p r o c e d u r e , a n d t c d e v e l o p and a d o p t d s t a i l e d d L r e e t i o n s w i t h r e p o l a t f o r m s f o r p r o p e r l y c o n d u c t i n g t h e s e r r e s of t e s t s ;

( c ) The Cnafrman w i l l p r e p a r e l i v e o r more s e t s u f i d e n t i c a l t e s t s p e c i m e n s a c c o r d i n g t o s p e c i f f c a t f o n s a n d d i r e c t i o n s , number them, make a r e c o r d of all n u m b e r s a n d mamokfngsp

and s e n d them w i t h d i r e c t i o n s a n d f o r m s t o t h e l a b o r a - t o r i e s w h e r e t h e t e s t s w i l l b e made;

( d ) After 5he t e s t da4;e. h a v e b e e n r s c e f v o d by t h e Chairman,

che G ~ o u p w i l l m e e t a g & i n r,c, c o n s i d a r t h e t e s t d a t a a n d i x s u r t secommended v a l u e s in t h e b l a n k s p a c e s i n t h e d s l i n i t i c n and p r e p a r e a r e p o r t t c b e s u b m i t t e d t o t h e S ~ ~ b c o r n m Y t t e s . I n A u ~ u s t , 1950, M r , Hewson r e s i g n e d a s t h e r e p r e s e n t a - t i v e of t h e l j a c i o n a l B e s e a r c h C o u n c i l o f C a n a d a o n S u b ~ c ~ m m i t t e e V crf A.S,"I',M, Comn-ittee E-,;, M r . G , t J . S h o r t e r o f t h e D f v i s f o n o f B i i f l d i n g R e s e a r c h w a s appo:n-,ad t h e nsw r o p r e s e n t a t f v e ,

The i a b o r a t o r y a t O h l o S t a t e Uni'vex3sity unclelatook to unpack s p e c i ~ e n m a t 1 3 r t a l s ; c u t them f o s p e c l m e n s i z e , i f n o t a l r e a d y c g t ; ark them; a n d k e e p f u l l r e c o i a d s or s o u r c e s , k i n d s , and l a b o r a t o r i e s . The f c l - l o w i n g c o d e l e t t e r s were a s s i g r i e d t o t h e l a b o r a - t o r i e s c o n d u c t i n g e x p e r i m e n t s o n PPO j e e t A-9: a , Natf o n a l R e s e a r c h C o u n c i l , D i v i s i o n o r Buf l d f ng R e s e a r c h , O t t a w a , Canada. b . N a t f o n a l B u r e a u o f S t a n d a r d s , W a s h i n g ~ o n , DOC, e , Gypsum A s s o c i a t i o n , Chf c a g o , I l l frrof s o

d , Owens-Corning F i b e r g l a s C o r p o r a t i o n , Newark, Ohio. e o Ohio S t a t e U n i v e r s i t y , Columbus, O h l o ,

k _{Fccr;lan nulneral was a s s l g n e d tc e a c h ccropsrzy, a s s o c i a t i o n}

(..c ci;her S G . A ? C ~ subnrlitting m a t e r i a l s tc. be f,es.ted and nunbe; s .were

,?,sd .Us: d s i . g : i a < e d i f f a r e n t m a t e r i a l s f rcm the same sil;r.:e.

The B r i t f s h a p p a r a t u s f o r i n z o m b u s t i b f l l . t y t e s t s ( B r i t f .3h

S t a n d a r d 476-1932), wi%h s l i g h t modff i c a ? : f on, was c i > n s t , r u c t , ~ d ky t h e N a t i . c n a 1 Bureau of S t a n d a r d s t o b e used f c r t h e 0 2 f a k u p i i k f l f Ly

5 e s t s . An Alundum f u r n a c e t u b e of

3-

i n c h i n s f d,e d i a m e t e r a n d 3 t % - ? n ~ h w ~ , ' i l t h i z k n e s s w a s used a s t h e inner- w s l i c f t h e fu;-naca, N x o b . 9 1

18

N i c h r o m e w i r e , t i ; . t a l l e n g t h about

49

f 3 3 t and w f 5 . h a r e ; - l a L a n c : e ~f

~ 5 . 5

_{ohms, .was u s e d a s t h e h e a t i n g element. T h i s w i r e .dhs embedded}

i n Al.undum cement. A r i g i d b u t r e l a t i v s l y s o f t asbestos b0ar.d about I n c h t h l z k was used f o r t h e h e a d s of t h e f u r n a c e . T l i s s r ~ h e d d e d

h e a t k g e l e m e n t and t h e f u r n a c e t u b s weye s e c u r e 5 aga1as.i; t h e heads

- r ~ f +3h A 1 u n . d ~ ~ ~ cerfie~?':.. The c o v e r was made i n 5wo ssrz8-cf r c u l a ~ p a r t s

of h r e f ~ a c t ~ r ' y rrlatel-fa1 a b o u t i / 2 i n z h t h i c k , T e r a m i n a l s or; t h e t o p head we,-e p r o v i d e d f o r t h e h e a t i l n g w i r e and t h a w i r e s o f t h e r m o c o u p l e

n

11. The tlibe f o r t h e p i l o t l i g h t had a n I n s i d e d i a m e t e r e f 0.05 f n c h . The f u r n a c e h a d an o u t s i d e d i a m e t e r of 9 Snches i n s t e a d o f t h e sqctire B r i t i s h d e s i g n . O t h e r d e t a i l s a r e shown I n F f g - 1.

2 T h e r a o c o u p l e s

T h e r r n c c o u p l ~ T was p l a c e d o n t h e o ~ c s i d e cf t h e Alundwn t u b e o f t h e f urmaze a b o u t which t h e h e a t i n g c o o i s were wound,

Therwocouple T?, ~ l a c ' e d i n t h e c e n t r e of t h e I n n e r t u b a below t h e epecfmen, i n d f 6 a t e d t h e t e m p e r a t u ~ e o f t h e a i r moying i n tlx t u b e , Whlle

T 2

was t c ba k e p t c o n s t a n t d u r i n g .the tssi;, 3.t; Tda.5 Fc,-.iuad.

thal; I t 'wks n o r e p r a c t i c a l t o c o n t , r o l T pather. khar, T?,

-

Thid was a;;,2~f...!sj, t , y v a r y i n g the v o l t a g e

supplies

b y msans: cf s varla:,

; - c n n e c . ! , e ~ 3 %n ser9s 3 ~ Z t h 4,he h e a t l n g e o f l D

Thz r e a s o n s f o r c o n r ; r o l l S n g TI r a t h e r thai T 2 a r e a s

f c 9 . l c s r s ~

( a ) The r e s p o n s e of thermocouple T2 t o c u r r s n t . c h a n g e s is

s l i g h t l y d e l a y e d when ecmpaped t o t h e r m o c c u p l e TI:

( 1

Thermocouple

TI

is n o t a f f e c t e d a p p a e ~ i a b l y b y t h s p r e s e n c e of a c o o l 0 2 s e l f - h e a t i n g spe.,in?sn a q d is

s a s i l y s u s t a i n e d a t a c c n s t a n t t e m p e r a S u r e d u l f n g t h e t e s t .

T h e r n o c o u p i e T3 was a t t a c h e d t o t h e siir*face af t h e specfmen

i f i most c a s e r . F o r i o o s e i n s u l a t i n g m a ~ e r f d s ,

T3

was i n s e r t e d f n t o

the :ewe? par<: 2f t h e specimen.

The t e m p e r a t u r e s of t h e t h r e e ther;mczouples wez.a t a k e n a t

cne-mindte i n t e r v a l s f o r t h e p u r p o s e of reccnzding t h e z r e n d o f any e x o t h e r m f c r e a ~ t f o n , Chromel-alumel w f r e s a f 24 B & S gauge w e P 9 used a s zhermocouples w f t h a b o u t

314

f n e h o f t h e i r l e n g t h twisted t o g e t h e r and welded by a b e a d f u s e d on t h e end. A p c r t a b P e

p r e c i s f o n p o t e n t i o m e t e r m a n u f a c t u r e d by t h e Rubicon C ~ r ~ ~ p a n y s f P h f l a d e l p h i a was used t o measure t h e t e m p e r a t m e s o f t h e : ; b e e

t h e r m o c o u p l e s . The c a l i b r a t i o n of t h e t h e r m o c o u p l e s 1s g i v e n by t h e f o l l o w i n g t a b l e f u r n i s h e d b y t h e N a t i o n a l Bureau o f S t a n d a r d s . E l e c t r o m o t i v e Force v s . T e r n p e r a t u ~ s o f Measuring J u n c t i o n ( r e f e r e n c e j u n c t i o n s 8% 3ZGFo ) Degree C . M i l l i v o l t s

Sample 1 Sampls 2 Sample

3

14.18

ao.

5 2

26.95

3.

Power Supply

The power was s u p p l i e d f r c m a 2 3 0 - v o l t I I n e . I n

o r d e r t o p r o t e c t t h e r e f r a c t o r y t u b e s from c r a c k i n g t h e I n f t f a l h e a t i n g was done s l o w l y w i t h c u r r e n t a t about

3

amperes and

60

v o l t s f o r t h e f i r s t f i v e m i n u t e s . Theri t h e c u r r e n t was g r a d d a l l y i n c ~ e a s e d t o 0 1 1 2 amperes and 1 0 0 volts i n t h e c c u r s e o f t h e n e x t 30 m i n u t e s . The t e m p e r a t u r e f o r thermoceupla

Tl

s h o u l d n e v e r e x c e e d 1 0 0 0 ~ C . The w i r i n g d i a g r a m i s shown in F i g . 2; a p h o k a g r a p h of t h e equipment i s shown i n F i g o

3 .

The p c r t a b l e p y r o m e t e r and s w i t c h No. 2 a r e a u x i l i a r y q g a i - a t u s , dsed a s a check on t h e p o t e n t i o m e t e r r e a d i n g s .

4.

A i r and Gas S u p p l i e s

A p p ~ o x f m a t a l y 2 c . f o m . of a f r , a s s t i g g e s t s d b y P r o f . Shank, were p a s s e d t h r o u g h t h e f u r n a c e . The a f r was t a k e n d f r e c ~ l y from t h e main s u p p l y f e e d i n g t h r d o 4 h a n e e d l e v a l v e .

A r e g u l a t o r was i n s t a l l e d i n t h e l f n e t o n ~ i n l r n f z e f 1 u e t u a f ; f c n u f n l f n e p r e s s u r e , The q u a n t f t y of aLr p a s v f n g t h r o d g h the f ~ r n a e e was measured by a r o t a m e t e r , E s s c t a n e , d P s t r ~ l b ~ z t e d by I m p e r f a l O i l L i m f t e d , was u s e d a s th.e g a s s u p p l y , a d s ~ p p l y was a d j u s t e d s o t h a t t h e f l a m e o f t h e p I l o t l i g h 5 was about

3/4

I n c h 1 ong

.

5,

S f z e of Specimen

The s i z e of specimen v a r i e s w f t h t h e t y p e of m a t ~ r l a l . The s t a n d a r d s f z e f o r c o m b u s t i b i l i t y t e s t s i s 1 182 by 2 by T

lnohea (where T i s t h e normal t h f c k n e s s el" t h e m a t e r f a l i f m d e r

1

112

i n c h e s ) .

6 ,

S u s p e n s i o n o f Speeirnen

W i r e - s c r e e n b a s k e t s o f b r a s s were made f o r t e s t f n g

f f l l i n s u l a t i o n w h i l e m e t a l l i c samples were suspended i n c r u c i b l e s o f n o t l e s s t h a n 1 / 2 c u b f c i n c h c a p a c f t y , M a t e r f a l s whfch k c u l d r e m a i n r i g i d d u r i n g t h e t e s t were suspended on w i r e l o o p s w h i l e

t h o s e which m e l t t o e i t h e r a vf s c o u s mass o r a b u b b l e were

h a l d i n w i r e - s c r e e n b a s k e t s . Owing t o a p p r e c i a b l a v a r i a t i o n s f n t h e t e m p e r a t u r e of t h e a f r i n t h e upper p o r t i o n o f t h e

i n n e r t ~ b e t h e specimen was p l a c e d

4

2/2 L o 6 _{1 / 2 i n c h e s from}

t h e t o p where t h e t e m p e r a t w e i s u n i f o ~ n w i t h i n

3"

t o

S°C.

7 .

_{O b s e r v a t i o n of Specimen}

A m i r r o r was h e l d d i r e c t l y above t h e f u r n a c s by a clamp a t t a c h e d t o a s t a n d and was i n c l l n e d a t an angae si, t h a t iL was p o s s f b l e t o make o b s e r v a t i o n s of t h e sljecfrnen d u r f n g t h e t e s t .

8.

P r o c e d u r e

When t h e a i r t e m p e r a t u r e T2 was s t a b i l i z e d a t 7S0°C. ('1382'F. ) w i t h i n

+

10°C,, a specimen o f t h e m a t e r f a l t o b e

t e s t e d Has suapenxed i n t h e i n n e r t u b e t o g e t h e r k i t h the~rnocoup2e

T 3 .

A g a s p i l o t flame w a s p o s f t i o n e d f o r i g n i t i n g any c o m b u s t f b l e

g a s g e n e r a t e d by t h e specimen and coming c u h f t h e openfng Yn the

tc,p of t h e f u r n a c e . The t h r e e tempelaature r e a d i n g s w a r e r e c o r d e d at, cne-minute l n t e ~ v a l s wf t h T

V%

and

Tg

t a k a n on t h e n ~ i r , u t e m d

T 3

t a k e n on t h e h a l f minute. s u a l o servaHiol-.de u ; r e made a s t o

b~I,gl?t,ness, f l a m i n g , b u b b l i n g , m e l t i n g of' t h o sps:*,mbnp OF any o t h e , ; p h e n ~ m e n o n whfch might be p e r t i n e n t .

The t e s t was c o n t i n u e d u n t i l t h e speeimsx f g n i t e d and i ~ ~ f n t e g r a t e d c o m p l e t e l y o r f o r

15

n l n u t e d f f disintegration had x o t o c c u r r e d d u r f n g t h a t t i m e . C a l c u l a t i o n s C c m ~ 1 ~ t a t 1 c . n c f S t a n d a r d D e v f a t f o n (d,S,T,M, Mal;tlal 3 r ~ T ~ e s s n t a t f on -- nf Data, 1540p p.17).

"The S t a n d a r d D e v i a t i o n r v may ba dsf5n.jd a s t h e sqLaros

I-.,. 5 of' mean c f t h e r q u a r e s of t h e indS1:ida~T davPa'ciLms

f ~ c a i :he mean sf a g i v e n s e t o f s i m - l l a ~ l y t a k e 2 da-ka,

where m = s t a n d a r d d e v i a t i o n f n "F.

T .=

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T2

T i m e c minute R u l 1

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1383OF. Run

3

T 2 = 1 3 8 j ° F ,

If g r e a t e r a c c u r a c y were r e q u i r e d , OF. a b s o l u t e s h o u l d have been u s e d i n s t e a d o f OF,

A t l e a s t two specimens o f a k i n d wepe t e s t e d and a n a v e r a g e c u r v e of t e m p e r a t u r e v e r s u s t i m e was p l o t t e d for" each o f t h e t h r e e thermocouple t e m p e r a t u r e r e a d i n g s f o r e a c h sampik, Ths c a l c u l a t e d v a l u e f o r t h e s t a n d a r d d e v f a t f c r n was p l s ~ k e d above and below e a c h c u r v e s o t h a t t h e s c a l e d l e n g t h s f t h e p l o t t e d v e r t i c a l l i n e was t w i c e t h a t o f t h e s t a n d a r d devf a t i o n . P e r t i n e n t o b s e r v a t i o n s were a l s o r e c o r d e d on t h e f n d f v f d u a l g r a p h s h e e t s . C o p f e s o f a l l t h e g r a p h s a r e i n c l u d e 6 a s an

Appendfx. D u p l i c a t e c o p i e s were s u b m i t t e d t o t h e Chairman cf" Subcommittee

V.

Reaommendatfons

A f t e r b e i n g u s e d f o r s e v e r a l months, t h e f u r n a s a began t o shoki d e t e r i o r a t i o n . Many o f t h e s c r e w s became l o o s s armd i t was d i f f i c u l t t o k e e p them s e c u r e i n t h e h e a d s of t h e f a m a c e , The h e a t i n g o f t h e f u r n a c e t o t h e o ~ e a s t f n g .:empeya- t u r e u s u a l l y 3ook a b o u t two h o u r s . A f t e r t h e f u r n a c e h a d b e e n f n use f o r s e v e r a l months, however, i t was f o u n d t h a t more t i m e

idas n e x s s a r y f o r a t t a i n i n g a s f m f l a ~ c o n d i t i o n , ALSO t h e r e f r a c t o r y m a t e r i a l u s e d a s t h e c o v e r was n o t very d u r a b l e and b r o k e q u i t e f r e q u e n t l y . I f t h i s t e s t i s t o b e u s e d f o r d e t e r m f - rifng t h e combustfbf l i t y o r i n c o m b u s t i b f l f t y of a m a t e r f a l , t h e f u r n a c e 3hould be c o n s t r u c t e d of more d u r a b l e rnaterf a l s ,

I n

o r d e r t o i n c r e a s e t h e e f f f c f e n c y o f t h i s t e s t , a

s t a n d a r d c r u c i b l e s h o u l d b e s e l e c t e d f o r a 1 1 t h e s a m p l e s I n srdsr t o a p p r o x i m a t e more c l o s e l y a t r u e c o m p a r i s o n cf t h e d i f f e r e n t m a t e r f 61s. The maximum a l l o w a b l e s l z e o f t h e sample was f o u n d t o b e r a t h e r l a r g e and d i f f i c u l t f o T f n s e r t f n g i n t o the f a ~ n a c e , S i n c e b o t h h a l v e s o f t h e c o v e r had t c bp, ~emolved when a maxfmurn-sized sample was used, t h e r e was much m c r s h e a s

l o s s a t t h e s t a r t of t h e t e s t t h a n when a smaller" sample was t e s t e d .

I t was f e l t t h a t t h e samples s h o u l d undergo a d e f i n i t e c o n d f t i o n i n g p r o c e d u r e p r i o r t o t h e t e s t , MF. S e t c h k f n c f t h e N a t i o n a l Bureau of S t a n d a r d s h a s s u g g e s t e d t h a t a d e s i c c a t o r w i t h a s a t u r a t e d s o l u t i o n of magnesium : h l o r i d e , h e l d a %

68OF.9.

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33

t o

34

p e r c a n t r e l a t i v e h u m i d i t y a t t h a t t e m p e r a t u r e , It was a l s o f e l t t h a t a s e l f - b a l a n c i n g p o t e n t i o - m e t e r c a p a b l e o f r e c o r d f n g h f g h t e m p e r a t u r e s o r an fr,dica"r;ng p y r c m e t s r s h o u l d b e used i n s t e a d of a s t a n d a r d p r e c f s f o n p o t e n t i - meter. I n t h i s c a s e more a t t e n t i o n c o u l d b e g i v e n f n r e c o r d i n g t h e maximum t e m p e r a t u r e a t t a i n e d d u r f n g t h e t e s t , .

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