Additional data on the combustibility rating of building materials using the B.S.I. furnace

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Additional data on the combustibility rating of building materials using the B.S.I. furnace

N A T I O N A L RESEARCH C O U N C I L CAN4DA D I V I S I O N O F B U I L D I N G RESEARCH A D D I T I O N A L DATA ON THE C O M B U S T I B I L I T Y R A T I N G O F B U I L D I N G M A T E R I A L S U S I N G

THE

B . S . I . FURNACE

by

A N A L Y Z E D

K,

Sumi and J o R o J u t r a s ~ e p o r t N o ,

96

of the D i v i s i o n o f B u i l d i n g R e s e a r c h OTTAWA: SEPTEMBER

1956

PREFACE

T h i s i s a supplement t o

DBR

R e p o r t NO.

43

and r e c o r d s an e x t e n s i o n of t h e work u n d e r t a k e n by t h e F i r e R e s e a r c h S e c t i o n of t h e D i v i s i o n o f B u i l d i n g R e s e a r c h i n a s s i s t i n g a subcommittee of t h e CSA Committee on F i r e P r e v e n t i o n and P r o t e c t i o n . T h i s Committee h a s been c h a r g e d w i t h t h e p r e p a r a t i o n of a new combus- ' t i b i l i t y t e s t s p e c i f i c a t i o n f o r Canada and t h e r e p o r t now p r e s e n t e d

i s a f u r t h e r r e c o r d o f i n v e s t i g a t i o n s u n d e r t a k e n i n t h i s c o n n e c t i o n , One of t h e a u t h o r s , M r . Kik Sumi, i n i t i a t e d t h e work

b e f o r e he l e f t f o r G r e a t B r i t a i n f o r s p e c i a l s t u d i e s i n f i r e r e s e a r c h from which he w i l l b e r e t u r n i n g a t ?he end of 1956.

The work h a s been c o n t i n u e d by h i s colleagues i n t h e F i r e R e s e a r c h S e c t i o n , n o t a b l y by h i s c o - a u t h o r , D r . J.R. J u t r a s . T h i s co-

o p e r a t i v e endeavour i s a p l e a s i n g f e a t u r e of t h i s i m p o r t a n t work i n a s i n g u l a r l y complex f i e l d .

Ottawa

ADDITIONAL DATA ON

THE

COMBUSTIBILITY RATING

OF BUILDING MATERIALS USING

THE

B.S,I. FURNACE

by

K,

Sumi and J , R , Jutras

I n a previous report "Comparison of Combustibility

Test Procedures"

(I),

resul%s of tests were given on the

combustibility of seven different building materials for the purpose of guiding the Canadian Standards AssociationVs Sub- committee on Noncombustibility in the preparation of a new

specification for the combustibility rating of materials, Two of the main conclusions of the work concerned the reliability of the criteria used for combustibility rating: the maximum temperature rise above the temperature in the fur- nqce at the beginning of the test, and the integrated area under

the time-temperature curve above the line

T

= Ti, where Ti rep-

resents the stabilized temperature of the furnace at the time of introduction of the specimen, Results of tests seemed to indi- cate that the temperature elevations were not consistent enough, through repeat tests on a given material, to serve as a basis for the grading of materials relative to their degree of combus- tibility, The use of this quantity however may be quite valid for the identification of materials as combustible or noncom-

bustible (21, The use of the integrated areas as a standard for

combustibility rating appeared to be justtfied, as measured val- ues were fairly reproducible and led to a classification of mat- erials that seemed consistent with experience.

Subject to the Subcommittee~s approval, a proposed

specification was prepared b y one of the authors (K.S. ), in

which the integrated areas served as a measure of combustibility. This specification provided for the classification of building materials within three different groups: noncombustible, low

combustible, and combustible, Area values of 100 and 1300 min-

utes-degrees Fahrenheit were specified as respective demarcation

points between the "noncombustiblen and "low combustible

"

groups

on the one hand, and the "low combustiblen and ltcombustiblet' groups on the othey, A simflar classification had been used

previously in German Standard DIN-4102

( 3 ) ,

It was suggested

for use in the proposed specification to provide a means of segregating from the readily combustible wood-based, or similar materials, those composed mainly of noncombustible substance which would add sufficient heat to a fire to debar them from the noncombustible group,

The test procedure recommended in this specification varied somewhat from that used in tests performed previously with

the British Standards Instftution furnace

(I),

The modificatiLons

concerned the pilot flame burner on the apparatus, as well as the

It had been n o t e d i n former t e s t s t h a t t h e p i l o t f l a m e was

o f t e n e x t i n g u i s h e d , and t h a t i t was d i f f i c u l t t o r e - i g n i t e . I t was f e a r e d t h i s might have some bdverse i n f l u e n c e on t h e r e p r o d u c i b i l i t y of t h e measurements, The u s e of a n a u x i l i a r y flame was t h e r e f o r e s u g g e s t e d a s a f u r t h e r means of s t a n d a r d i z i n g t h e p r o c e d u r e f o r r e - i g n i t i n g t h e f l a m e , P r e l i m i n a r y t e s t s on a system % h e r e t h e a u x i l i a r y f l m e was l o c a t e d on t h e same l e v e l a s , and T i n c h away

from t h e f i r s t , had proved v e r y s u c c e s s f u l , The a u x i l i a r y f l a m e remained l i t , p r o v i d i n g a c o n t i n u o u s s o u r c e of r e - i g n i t i o n f o r t h e p i l o t flame, I t was t h e r e f o r e t h o u g h t d e s i r a b l e t o i n c l u d e s u c h a m o d i f i c a t i o n i n t h e proposed s p e c i f i c a t i o n , C u r i n g c o n d i t i o n s a d o p t e d i n p r e v i o u s t e s t s (1) were, a s s p e c i f i e d i n B r i t i s h S t a n d a r d 476:1953 ( 2 ) . T h i s s t a n d a r d s t i p u l a t e s t h a t " t h r e e of t h e ( s i x ) t e s t sgecimens s h o u l d be d r i e d by h e a t i n g t o a t e m p e r a t u r e of 1 0 0 ~ C . (212 F. ) f o r

s i x

h o u r s , ,

.

The r e m a i n i n g t h r e e specimens should be k e p t f o r a p e r i o d o f one week i n a d e s i c - c a t o r c o n t a i n i n g c a l c i u m c h l o r i d e , b e f o r e t e s t i n g . "

From e x p e r i e n c e g a i n e d by S , H o I n g b e r g , f o r m e r l y of t h e N a t i o n a l Bureau of S t a n d a r d s i n Washington, however, i t was b e l i e v e d t h a t c u r i n g c o n d i t i o n s c o u l d be improved by e x p o s i n g specimens t o a t e m p e r a t u r e o f 60°C. (140°F.) f o r a p e r i o d o f 24 t o

48

hours. The s e l e c t i o n of t h i s a r b i t r a r y t e m p e r a t u r e seems t o have been b a s e d on t h e f a c t s t h a t maximum r e l a t i v e humidity u n d e r such c o n d i t i o n s

c o u l d n o t g r e a t l y exceed 1 6 p e r c e n t , and t h a t t h e d i s t i l l a t i o n r a t e of v o l a t i l e s from some of t h e specimens would n o t be e x c e s s i v e

(4),

S i n c e t h e s e c u r i n g c o n d i t i o n s a r e f a v o u r e d i n t h e U n i t e d S t a t e s i n t h e p r e p a r a t i o n of a s i m i l a r t e s t method f o r d e t e r m i n i n g t h e combus- t i b i l i t y of m a t e r i a l s

( s ) ,

t h e u s e of s i m i l a r c o n d i t i o n s was s u g g e s t e d i n t h e p r o p o s e d s p e c i f i c a t i o n ,

A t a m e e t i n g of t h e Subcommittee, t h e proposed s p e c i f i c a - t i o n was t h r o u g h l y s c r u t i n i z e d . The t h r e e f o l d c o m b u s t i b i l i t y group- i n g , a s w e l l a s t h e m o d i f i c a t i o n s c o n c e r n i n g t h e p i l o t flame and t h e c o n d i t i o n i n g of specimens, were a g r e e 4 upon unanimously. There was, however, u n c e r t a i n t y about t h e s u i t a b i l i t y of t h e a r e a v a l u e s b e i n g s p e c i f i e d a s demar8cation p o i n t s between t h e c o m b u s t i b i l i t y

g r o u p s , s i n c e t h e s e l e c t i o n of t h e s e v a l u e s had been b a s e d on o n l y a few t e s t r e s u l t s from a r e l a t i v e l y small number of m a t e r i a l s , A d d i t i o n a l t e s t s were t h o u g h t d e s i r a b l e a s a f u r t h e r check. The Subcommittee recomiiended

( 6 )

t h a t t h e F i r e R e s e a r c h S e c t i o n under- t a k e t e s t s on t h e f o l l o w i n g m a t e r i a l s , a d h e r i n g t o t h e p r o c e d u r e o u t l i n e d i n t h e proposed s p e c i f i c a t i o n :

1, 3/8-inch p l a s t e r b o a r d and m i n e r a l wool b a t t ( p a p e r b a c k e d ) Both t h e s e m a t e r i a l s had been t e s t e d (1) a c c o r d i n g t o t h e p r o c e d u r e d e s c r i b e d i n BSI 476:1953 and were s e l - e c t e d t o p e r m i t an e v a l u a t i o n of t h e e f f e c t of changes made i n t h e t e s t i n g p r o c e d u r e ;

2 ,

0

T h i s m a t e r i a l was i n c l u d e d i n t h e group t o o b v i a t e a s i t u a t i o n e x i s t i n g p r e v i o u s l y (1) whereby no c o n c l u s i o n s c o u l d be d-rawn from a c o m p a r a t i v e a n a l y s i s of r e s u l t s of t e s t s on two i n s u l a t i n g m a t e r i a l s , One, m i n e r a l wool b a t t , was p a p e r backed whereas t h e o t h e r , g l a s s wool b a t t , was

composed e x c l u s i v e l y of g l a s s wool,

3,

A s b e s t o s p a p e r w i t h o r g a n i c b i n d e r T h i s new m a t e r i a l was s e l e c t e d t o o b t a i n d a t a on t h e b e h a v i o u r of one w e l l r e c o g n f z e d i n c o m b u s t i b l e compound when t e s t e d under t h e p r e s e n t p r o c e d u r e , EXPERIMENTAL DETAILS Apparatus

The a p p a r a t u s used f o r t h e t e s t s was t h e same a s t h e a p p a r a t u s of t h e B r i t i s h S t a n d a r d s I n s t i t u t i o n ( I ) , e x c e p t f o r t h e minor m o d i f i c a t i o n t o t h e p i l o t f l a m e b u r n e r , shown i n F i g , 1. T e s t i n g Procedure

+

P r i o r t o t e s t i n g , specimens were d r i e d a t 140°1?.,,

S?F.,

f o r n o t l e s s t h a n 24 h o u r s , n o r m o r e t h a n

48

hours, and allowed t o c o o l t o room t e m p e r a t u r e i n a d e s i c c a t o r o v e r c a l c i u m c h l o r i d e . S i z e and d e t a i l s of specimens, t h e i r method of s u p p o r t and t h e method o f t e s t , were s i m i l a r t o t h o s e d e s c r i b e d p r e v i o u s l y ( 1 ) p e r t a i n i n g t o t h e use o f t h e BSI f u r n a c e . RESULTS The p r o g r e s s of e a c h t e s t was f o l l o w e d by n o t i n g t h e sequence of t h e v i s u a l l y o b s e r v a b l e e v e n t s w h i l e t e m p e r a t u r e s

a t

t h e thermocouple were b e i n g r e c o r d e d a u t o m a t i c a l l y a t r e g u l a r 30- second i n t e r v a l s , V i s u a l O b s e r v a t i o n s

S i n c e two secondary o b j e c t s of t h e s e t e s t s were t o e v a l u a t e t h e performance of t h e p i l o t f l a m e when p r o v i d e d w i t h an a u t o m a t i c r e - i g n i t e r , a nd t o d e t e r m i n e t h e i n f l u e n c e of t h e new i g n i t i o n system on t h e p r o g r e s s of t h e combustion, t h e v i s u a l o b s e r v a t i o n s a r e r e p o r t e d i n T a b l e I , Although t h e s e d a t a have been a v e r a g e d o v e r a number o f r e p e a t t e s t s , c l o s e agreement was found between i n d i v i d u a l t e s t s ,

Good agreement i s a l s o e v i d e n t between t h e s e d a t a and s i m i l a r o b s e r v a t i o n s made i n p r e v i o u s t e s t s ( a l s o i n c l u d e d i n Table I ) e x c e p t f o r t h e t i m e s of r e - i g n i t i o n of t h e p i l o t f l a m e , The d e v i a t i o n i s p a r t i c u l a r l y g r e a t i n t h e c a s e o f p l a s t e r b o a r d ,

b u t , i n t h e a u t h o r s d o p f n i o n , t h i s s h o u l d n o t b e of g r e a t c o n c e r n s i n c e , i n t h e development of a s t a n d a r d method of t e s t i n g , one must aim a t a s i m p l e p r o c e d u r e t h a t c a n be rnade a s uniform a s p o s s i b l e t h r o u g h r e p e a t t e s t s , On t h e s e grounds, t h e u s e of an a u x i l f a r y flame must b e recommended,

Temperature Records

The r e c o r d e d t e m p e r a t u r e s were r e a d o f f t h e c h a r t a t each minute mark and p l o t t e d a g a i n s t t i m e f o r e a c h t e s t on e a c h of t h e f o u r m a t e r i a l s t e s t e d ( F i g 3 , 2,

3,

4,

and

5 ) ,

The a r e a s

under t h e c m v e s above t h e i n f t i a k f u r n a c e t e m p e r a t u r e T ( c a . 1 3 8 2 ' ~ ~ ) were i n t e g r a t e d from t h e g r a p h s , u s i n g s p l a n i m e t e r , ~ h & i r v a l u e s

a r e t a b u l a t e d i n Table I1 (column A ) w f t h t h e c o r r e s p o n d i n g maximum t e m p e r a t u r e r i s e s measured d i r e c t l y o f f t h e r e c o r d e r ' s c h a r t (column

D),

S i m i l a r r e a d i n g s , o b t a f n e d i n p r e v f o u s t e s t s

on t h e same m a t e r f a l s , have a l s o been Y f s t e d t o p e r m i t a c o m p a r a t i v e a n a l y s i s of r e s u l t s from t e s t s on a g i v e n m a t e r f a l under v a r i o u s c o n d i t i o n i n g s ,

It i s n o t e d t h a t t h e r e s u l t s g i v e n f o r g l a s s wool b a t t do n o t r e f e r i n a 1 1 c a s e s t o t h e same commercial p r o d u c t ,

The specimens t e s t e d , u n d e r t h s c o n d i t i o n s d e t a l l e d i n t h f s

r e p o r t , were backed w i t h p a p e r , whereas t h o s e t e s t e d f o r m e r l y were composed e n t i r e l y of g P a ~ s wool,

I n F i g s ,

6

and

7 ,

u s e f s made of t i m e - t e m p e r a t u r e c u r v e s p u b l i s h e d i n DBR R e p o r t No,

43

t o measure t h e i n f l u e n c e of c u r i n g c o n d i t i o n s on t h e e v o l u t i o n o f t h e combustion w i t h t i m e , These c u r v e s have been o b t a i n e d from t e m p e r a t u r e s a v e r - aged a t e a c h minute mark o v e r r o p e a t t e s t s on p l a s t e r b o a r d and m i n e r a l wool, I n ~ i g ,

8,

s i m i l a r c u r v e s a r e g f v e n f o r g l a s s wool t o e s t i m a t e t h e h e a t c o n t r i b u t e d by t h e p a p e r when s u c h m a t e r f a l i s used a s backfng, and a l s o t o measure i t s i n f l u e n c e

on t h e maximum e l e v a t i o n o f t h e t e m p e r a t u r e d u r i n g t h e t e s t s , DISCUSSION

Although t h e maln o b j e c t of t h i s work was m e r e l y t o t e s t f u r t h e r t h e s u i t a b i l i t y o f t h e a r e a v a l u e s t s n t a t f v e l y s e t a s l i m f t s be-bween t h r o e a r b j t r a r y c o m b u s t i b i l i t y g r o u p s f o r b u i l d i n g m a t e r i a l s , additional c o n c l u s f o n s on s e c o n d a r y a s p e c t s of t h e work can a l s o be drawn from an a n a l y s i s of t h e t e s t r e s u l t s , Such conclusions c o n c e r n t h e v a r f a b i l f t y of a r e a v a l u e s t h r o u g h r e p e a t t e a t s on a g i v e n m a t e r i a l , t h e e f f e c t of t h e m o d i f f c a t i o n s t~ t h e p r e v i o u s z e s t i n g p r o e e d u r e on t h e r e s u l t s , and t h e h e a t c o n t r 2 i b u t e d by t h e p a p e r when paper-backed specimens of o t h e r w i s e incombustible m a t e r i a l s a r e t e s t e d ,

Limit Values f o r t h e Combustibi l i t g Groups

O f t h e f o u r m a t e r i a l s t e s t e d , t h e a s b e s t o s paper i s t h e o n l y one known t o be of a noncombustfble n a t u r e , Zero v a l u e s ( T a b l e 11) f o r . t h e a r e a u n d e r t h e c u r v e , a s w e l l a s f o r t h e t e m p e r a t u r e r i s e , a r e t h e r e f o r e t o be e x p e c t e d f o r t h i s m a t e r i a l ,

The t h r e e o t h e r m a t e r i a l s had a p a p e r b a c k i n g which w i l l , under normal c o n d i t i o n s , i m p a r t t o them some d e g r e e of c o m b u s t i b i l i t y a l t h o u g h t h e y a r e m a i n l y composed of f n g r e d i e n t s a c c e p t e d a s noncombustible, N e v e r t h e l e s s , t h e p a p e r b a c k i n g forms o n l y a s m a l l p r o p o r t i o n o f t h e p r o d u c t s a s such, and c o u l d n o t c o n t r i b u t e enough h e a t t o j u s t i f y t h e c l a s s i f i c a t i o n of t h e s e m a t e r i a l s w i t h such c o m b u s t i b l e b u i l d i n g p r o d u c t s a s wood and wood fibreboard, I n a l l f a i r n e s s , t h e r e f o r e , a c o m b u s t i b i l i t y t e s t method should a l l o w f o r a s p e c i a l c l a s s , w i t h i n which m a t e r i a l s of low c o m b u s t i b i l i t y c o u l d be grouped,

Mean a r e a v a l u e s , r e s u l t i n g from t h e l a s t s e r i e s of I

t e s t s on p l a s t e r b o a r d , m i n e r a l wool and g l a s s wool ( p a p e r b a c k e d ) , e x t e n d from

331

t o 913 m i n u t e s - d e g r e e s F a h r e n h e i t ( T a b l e 11, column A ) , t h i s r a n g e b e i n g i n c r e b s o d t o l i m i t v a l u e s of 222 and 1280 m i n u t e s - d e g r e e s F a h r e n h e i t when r e s u l t s from i n d i v i d u a l t e s t s a r e t a k e n i r f t o c o n s i d e r a t i o n , Most of t h e r e s u l t s o b t a i n e d p r e v i o u s l y on t h e same m a t e r i a l s ( i n c l u d i n g g l a s s wool w i t h o u t p a p e r b a c k i n g ) , under o t h e r t y p e s of c o n d i t i o n i n g , f i t w i t h i n t h a t r a n g e of v a l u e s , T h e r e f o r e , i t becomes e v i d e n t t h a t t h e t h r e e m a t e r i a l s would f a l l i n t o t h e "low c o m b u s t i b i l i t y ' ' group s h o u l d t h e p r e s e n t t e n t a t i v e l i m i t s of 100 and 1300 m i n u t e s - d e g r e e s F a h r e p h e i t be a c c e p t e d as d e m a r c a t i o n v a l u e s between t h e t h r e e c ~ m b u s t i b f i i t ~ groups, Under t h e c o n d i t i o n s of t h e p r e s e n t t e s t s , d i f f e r e n t v a l u e s of c o m b u s t i b i l i t y were o b t a i n e d f o r t h e two p a p e r backed m a t e r i a l s , m i n e r a l wool and g l a s s wool, T e s t s on t h e m i n e r a l

WOOL

specimens r e s u l t e d i n a mean a r e a v a l u e a l m o s t t h r e e t i m e s

a s g r e a t as t h a t o b t a i n e d f o r t h e g l a s s wool specimens, T h i s may be due p a r t l y t o d i f f e r e n c e s i n t h e t h i c k n e s s of t h e p a p e r b a c k i n g , t h e n a t u r e of t h e a d h e s i v e compound used t o hold t h e p a p e r t o t h e m a t e r i a l and t h e t y p e of b i n d e r i n t h e wool p r o p e r ,

With r e g a r d t o t h e p l a s t e r b o a r d , i t must be emphasized t h a t t h e specimens were made up of f o u r t h i c k n e s s e s t o conform t o t h e p r e v i o u s l y s p e c i f i e d specimen s i z e ( 1) , T h e r e f o r e , spec- imens of t h i s m a t e r i a l c o n t a i n e d e i g h t l a y e r s of p a p e r i n s t e a d of t h e two o r i g i n a l l y found i n t h e commercfal p r o d u c t , Although t h i s p r o c e d u r e may n o t r e n d e r f u l l J u s t i c e t o p l a s t e r b o a r d , t h i s p a r t i c u l a r m a t e r i a l , b e i n g p a r t l y composed of p a p e r , would f a l l somewhere w i t h i n t h e nlow c o m b u s t i b f l i t y " p o u p even under i d e a l t e s t c o n d i t i o n s , I t f e l l w i t h i n t h i s r a n g e when t e s t e d , a s d e s - c r i b e d p r e v i o u s l y ; t h i s p r o c e d u r e f o r p r e p a r i n g specimens i s t h u s c o n s i d e r e d s a t i s f a c t o r y f o r t h e p r e s e n t ,

V a r i a b i l i t y o f R e s u l t s

I n DBR R e p o r t No.

43

( l ) , t h e v a r i a b i l i t y of t h e r e s u l t s was i l l u s t r a t e d o n l y g r a p h i c a l l y . C u r v e s f r o m r e p e a t

t e s t s s5owed c l o s e s i m i l a r i t y and i t was assumed t h a t a r e a

v g l u e s f r o m individual t e s t s w e r e of a ~ o o d r e p r o d u c i b i l i t y . I n t h e p r e s e n t s t u d y , t h e v a r i a t i o n o f t h e t e m p e r a t u r e w i t h t i m e d u r i n g r e p e a t t e s t s on a g i v e n m a t e r i a l , f o l l o w e d v e r y c l o s e l y t h e same g e n e r a l p a t t e r n ( F i g s . 2 ,

3,

4

and

5)

e x c e p t t h a t t h e p l a s t e r b o a r d s p e c i m e n s showed l e s s c o n s i s t e n c y . It was t h e r e f o r e t h o u g h t w i s e a t t h i s s t a g e t o c h e c k more c l o s e l y t h e v a r i a b i l i t y of r e s u l t s b y m e a s u r i n g a r e a s u n d e r t i m e - t e m p e r a t u r e c u r v e s f o r e a c h t e s t . The r e a d i n g s s5owed v a r i a t i o n s g r e a t e r t h a n s u s p e c t e d ( T a b l e 11, column A ) . S i m i l a r m e a s u r e m e n t s were made on g r a p h s f r o m p r e v i o u s t e s t s c a r r i e d o u t on t h e same m a t e r i a l s u s i n g t h e BSI a p p a r a t u s ( c o l u m n s B a n d C ) . Although d e v i a t i o n s h e r e a r e n o t a s l a r g e a s t h o s e e x p e r i e n c e d i n t h e p r e s e n t t e s t s , some c l o s e r r e p r o d u c i b i l i t y i s d e s i r a b l e , s i n c e t h e p r o p o r t i o n of t h e s t a n d a r d d e v i a t i o n of i n d i v i d u a l a r e a v a l u e s t o t h e mean v a l u e i s a l m o s t a s g r e a t a s , and i n some c a s e s g r e a t e r t h a n , t h a t o f t e m p e r a t u r e e l e v a t i o n s . T h i s , i t i s b e l i e v e d , i s of g r e a t i m p o r t a n c e i n t h e d e v e l o p m e n t o f a s t a n d a r d method o f t e s t i n g and a f u r t h e r s t u d y o f t h e s u b j e c t w i l l b e made i n a f o l l o w i n g r e p o r t . E f f e c t of P I o d i f i c a t i o n s

--

i n t h e T e s t i n g P r o ~ e d u r e V a r i a t i o n s i n t h e method o f c o n d i t i o n i n g t h e s p e c i m e n s seem t o have a n e g l i c g i b l e e f f e c t on t h e s e q u e n c e and n a t u r e of e v e n t s o b s e r v e d d u r i n g t e s t s ( T a b l e I ) . The o n l y a p p a r e n t d i f f e r e n c e b e t w e e n t h e two s e t s of o b s e r v a t i o n s i s t h a t t h e o i l o t f l a m e s t a g s o u t f o r a l o n g e r p e r i o d u n d e r t h e c o n d i t i o n s o f t h e p r e s e n t t e s t s . T h i s was a t t r i b u t e d t o t h e m o d i f i c a t i o n mud.e i n t h e p r o c e d u r e f o r r e - i g n i t i n g t h e p i l o t f l a m e . The g e n e r a l p a t t e r n o f t e m p e r a t u r e v a r i a t i o n s d u r i n g t e s t s i s s c a r c e l y i n f l u e n c e d by t h e t y p e of c o n d i t i o n i n i n t h e c a s e s of m i n e r a l wool ( F i g .

7 )

and g l a s s wool ( F i g .

8

,

c u r v e s B and C ) . With p l a s t e r b o a r d , a d i f f e r e n t p a t t e r n was o b s e r v e d f o r e a c h s e t of c u r i n g c o n d i t i o n s ( F i g .

6 ) .

O f more c o n c e r n , however, i s t h e e f f e c t o f c o n d i t i o n - i n g on t h e a c t u a l r e s u l t s o f t e s t s . T a b l e I1 shows t h a t , r e l a t i v e t o c o n d i t i o n i n g , t h e t r e n d of t h e v a r i a t i o n s b e t w e e n a r e a v a l u e s i s s i m i l a r t o t h a t of t h e v a r i a t i o n s o b s e r v e d b e t w e e n t e m p e r a t u r e , r i s e s . It d i f f e r s , however, f r o m one m a t e r i a l t o a n o t h e r , i n d i c a t i n g t h a t m a t e r i a l s a r e n o t a l l a f f e c t e d i n t h e same way b y t h e method o f c o n d i t i o n i n g u s e d . Some m a t e r i a l s , if d r i e d i n a n oven a t a t e m p e r a t u r e of 2 1 2 O ~ . , w i l l l o s e i n f l a m m a b l e v o l a t i l e s and c o n s e q u e n t l y w i l l show a l o w e r c o m b u s t i b i l i t y . I n S r l t i s h S t a n d a r d 476:1953, t h i s i s

circumvented by c o n d i t f o n i n g some o f t h e specimens o v e r c a l c i u m c h l o r i d e

( 7 ) .

On t h e o t h e r hand, m a t e r i a l s which have a t e n d e n c y t o combine w a t e r w i l l show a lower c o m b u s t i b i l i t y i f c o n d i t i o n e d o v e r c a l c i u m c h l o r i d e and a h i g h e r one i f d r i e d a t 2 1 2 ' ~ . A

c o m p a r a t i v e a n a l y s i s of t h e r e s u l t s l i s t e d i n Table I1 i n d i c a t e s t h a t t h e c u r i n g c o n d i t i o n s used i n t h e p r e s e n t t e s t s ( d r y i n g a t

1 4 0 ~ ~ ~ )

a r e c l o s e t o b e i n g n p r a c t i c a l medium between t h e two s e t s of c o n d i t i o n s s p e c i f i e d i n B r i t i s h S t a n d a r d 476:1953.

Heat C o n t r i b u t e d by t h e Paper Backing

-

Curves a r e g i v e n i n ~ i g .

8

t o i l l u s t r a t e t h e e f f e c t of p a p e r b a c k i n g on t e m p e r a t u r e v a r i a t i o n d u r i n g t e s t s on g l a s s wool. When t e s t i n g paper backed specimens, i t i s t o b e e x p e c t e d

t h a t , under t h e s e v e r e c o n d i t i o n s of t h e t e s t , f l a m i n g w i l l t a k e p l a c e a s soon a s t h e specimen i s p l a c e d i n t h e f u r n a c e , a s

e v i d e n c e d by t h e s m a l l peak a p p e a r i n g a t t h e one-minute mark i n c u r v e A . T h i s c a u s e s t h e maximum t e m p e r a t u r e r i s e t o be much g r e a t e r t h a n t h a t measured on unbacked specimens; i t a c t u a l l y t r i p l e s t h e v a l u e i n t h e c a s e of g l a s s wool ( T a b l e 11, columns D, E and F ) . S i n c e t h e p a p e r b u r n s r a p i d l y , however, i t s

p r e s e n c e h a s r e l a t i v e l y l i t t l e i n f l u e n c e on t h e i n t e g r a t e d a r e a , t h e h e a t c o n t r i b u t e d by t h e p a p e r b e i n g e q u i v a l e n t t o l e s s t h a n o n e t h i r d of t h e t o t a l h e a t produced by t h e whole specimen ( ' l ' a b b

11, columns A, B and C ) , CONCLUSION

-

The r e s u l t s o b t a i n e d from t h e s e t e s t s show t h a t , under t h e c o n d i t i o n s and p r o c e d u r e d e s c r i b e d , t h e f o u r m a t e r i a l s w i l l

e x h i b i t mean a r e a v a l u e s a s f o l l o w s :

a ) A s b e s t o s Faper

...

0 Min.

x

O F .

b ) G l a s s Wool B a t t ( p a p e r b a c k e d )

....

331

Min.

x

OF.

C ) P l a s t e r b o a r d ,

...

833 Min.

x

OF.

d ) M i n e r a l Wool A a t t ( p a p e r backed).. 913 Min.

x

OF.

The p r e s e n t method of t e s t , however, h a s t h e d i s a d v a n - t a g e of a l l o w i n g s t a n d a r d d e v i a t i o n s f r o m mean v a l u e s t o be

l a r g e r t h a n e x p e c t e d , which s u g g e s t s a need f o r f u r t h e r r e f i n e - ment and d e f i n i t i o n of t h e t e s t c o n d i t i o n s

F i n a l l y , t h e r e were some i n d i c a t i o n s t h a t t h e c o n d i t i o n s adopted f o r t h e c u r i n g o f specimens a r e c l o s e t o s i m u l a t i n g a mean of t h e two s e t s of c o n d i t i o n s s p e c i f i e d i n B r i t i s h S t a n d a r d

/+76:1953, whereas t h e h e a t c o n t r i b u t e d by t h e p a p e r i n t h e t e s t i n g of p a p e r backed g l a s s wool amounts t o o n l y FI s m a l l f r a c t i o n of t h e

t o t a l h e a t l i b e r a t e d by t h e specimen under t h e c o n d i t i o n s of t h e t e s t .

REFERENCES

1. Sumi, K O Comparison of C o m b u s t i b i l i t y T e s t Procedures. N a t i o n a l R e s e a r c h Council, D i v i s i o n of B u i l d i n g Research, DBR Report No.

[.~3,

J u l y 1 9 5 5 ~ 16 p. 2. F i r e T e s t s on B u i l d i n g M a t e r i a l s and S t r u c t u r e s . B r i t i s h S t a n d a r d s I n s t i t u t i o n , B r i t f s h S t a n d a r d 476:1953, London, 24 P.

3.

R e s i s t a n c e of Bufldfng M a t e r i a l s a n d S t r u c t u r a l Components t o F i r e and Heat, 2nd ed. German S t a n d a r d DIN-4102 November 1940. T r a n s l a t e d by t h e N a t i o n a l Research Council, Ottawa.

4.

Robertson, A,F. P r i v a t e communication from N a t i o n a l Bureau of S t a n d a r d s , Washington, A p r i l 1954.

5.

Minutes of Meetfng of Subcommittee V (liomenclature and

~ e f i n i t i o n s ) of ASTM Committee

E-5,

Washington, D.C.,

4

Feb. 1954.

6.

Minutes of Meeting of Subcommittee on N o n c o m b u s t i b i l i t y of Committee

B-54,

Canadian S t a n d a r d s A s s o c i a t i o n ,

13

J u l y 1954.

7.

Nash,

P.

P r i v a t e communication from J o i n t F i r e Research O r g a n i z a t i o n , Boreham Wood, England, November 1953.

TABLE I

VISUAL OBSERVATIONS

PREVIOUS TESTS PRESENT TESTS

PLASTERBOARD

P i l o t flame g o e s out a t s t a r t of t e s t . P i l o t flame g o e s out a t s t a r t of t e s t . Flaming accompanied by l i g h t smoke Flaming accompanied by l i g h t smoke d u r i n g f i r s t minute of t e s t . d u r i n g f i r s t minute of t e s t .

P i l o t flame r e - i g n i t e d manually a t E i l o t f l a m e r e - i g n i t e d a u t o m a t i c a l l y a t

t i m e 4 minutes and about 2 i n c h e s high. time 8 minutes and about 1* i n c h e s h i g h . Specimen glowing between l a g e r s a t Specimen glowing between l a y e r s a t end of t e s t . end of t e s t .

MINERAL WOOL

P i l o t f l a m e goes o u t a t s t a r t of t e s t . P i l o t f l a m e goes o u t a t s t a r t of t e s t . Flaming w i t h g e n e r a t i o n of b l a c k smoke I n t e r m i t t e n t f l a m i n g w i t h g e n e r a t i o n of f o r o v e r 1 minute a t s t a r t of t e s t . b l a c k smoke d u r i n g f i r s t 3 0 seconds of

t e s t .

P i l o t flame r e - i g n i t e d manually a t P i l o t flame r e - i g n i t e d a u t o m a t i c a l l y a t time 1 minute, 15 seconds and normal. t i m e 2 m i n u t e s and 1& i n c h e s h i g h . Specimen glowing a t end of t e s t . Specimen glowing a t end of t e s t .

GLASS WOOL

( p a p e r backed)

F l a s h i n s i d e f u r n a c e and p i l o t flame g o e s o u t .

Flaming accompanied by b l a c k smoke d u r i n g f i r s t 3 0 s e c o n d s of t e s t .

P i l o t f l a m e r e - i g n i t e d a u t o m a t i c a l l y a t time 4 0 seconds and a b o u t 1; i n c h e s high. Glowing of specimen a t end of t e s t .

ASBESTOS PAPER

P i l o t f l a m e about 1 i n c h h i g h a t s t a r t of t e s t .

P i l o t flame goes o u t a t t i m e 30 seconds. P i l o t f l a m e r e - i g n i t e d a u t o m a t i c a l l y a t time 3 m i n u t e s and a b o u t 1 i n c h high. Specimen f l o w s between l a y e r s a t end of t e s t .

d

No d a t a a v a i l a b l e .

INTEGRATED AREAS AND TEMPERATURE ELEVATIONS

--

AT V A R I O U S CONDITIONINGS MATERIAL I n t e g r a t e d Areas jminxte li

"F)

Temperature E l e v a t i o n s

( 9 )

Conditionfng: (A]

i'

13) ( d l

(D

>

$ E l ( F ) l & o ° F 21'2OF o v e r

1409

2 1 2 9 o v e r 6 a @ P 2 CaC12 PLASTERBOARD T e s t 1

roqo

1x53

'778

110 306

158

T e s t 2 824 PO20 1065

85

216 T e s t

3

8h.3

1065 8 36 rn

-

72 296 T e s t

4

594

65

I

:;;

_-

MEAN

-

-.-.

8

3 3

.

,.::&-.i

-

"1 '7 ",:- O ,

,3

;,cj 2, - ?

L!2

a

Standard Deviation- 2 .

6%

14%

20%

14%

13%

MINERAL WOOL T e s t 1 708

' I

841

T e s t 2 2280

5

1020 T e s t

3

872

65'1

935

T e s t

&

792 ( P )

-

MEAN

-

_=-.

₍₉

_c12!

_.

-

&'"7

-

₉₃₂ Standard Devi a t 1 on-

a%

13%

8%

GLASS WOOL With No

Nc

With No No

PB(?g= PB c v - ="cw. PR

--

PB

-

PB

-

PB Test 1

4

36

29$

3

r

j 1.12 2212

r b S

T,79

162

42

58

Tes% 2

_-

50

-

30

T e s t

3

3%

298

₁₂₅

₃₈

MEAN

-

Standard Deviation- 26% 22% 23% ASBESTOS PAPER -- -, ~ e s t 1

e

DD

-

T e a t 2 0

-

LD MEAN

-

-

0 m

-

( * ) PB = Paper back.

$STEEL ROO.

TIME IN M I N U T E S

0

1

2

3

4

5 6

7 8 9 1 0 1 1 1 2 1 3 1 4 ' l 5 1 6

h I I I I I I I 1 I I I I I I 1

TEST

NO.

1

-

-

-

I I I I I I I I I I I I I I 1

-

_TEST

_NO.

₂

-

-

~i

/3

-

I I I I I I I I I I I I I I 1 I I I I I I I I I I I I I I I

-

TEST

NO.

3

-

-

-

~i

9

-

I I I I I I I I I I I I I I I I I I I I I I I I I I I I I 1

1500

-

_TEST

_NO.

₄

-

-

-

1400

~

i

q

-

I I I I I I I I I I I I I I I

0

1

2

3 4 5 6

7 8

9

1 0 1 1 1 2 1 3 1 4 1 5 1 6

T I M E IN MINUTES

F I G U R E

2

V A R I A T I O N O F T E M P E R A T U R E

AT

THERMO-

C O U P L E

DURING

INDIVIDUAL

T E S T S

O N

P L A S T E R B O A R D .

D B R . REPORT 96.

T I M E IN

M I N U T E S

0 1

2

3

4

5

6

7

8

9 1 0 1 1 1 2 1 3 1 4 1 5 1 6

I I 1 I I I I I I I I

T E S T

NO.

1

-

-

T i 7

-

I I I I I I I I I I I I

TEST NO.

2

-

-

~ i / 7

-

I I I I I I 1 I I I I I I I I

TEST

NO.

3

-

-

-

I I I I I I I I I I I

T E S T

NO.

4

-

-

~i

9

I I I I I I I I I I I I I I I

0

1

2

3 4 5

6

7

8

9 1 0 1 1 1 2 1 3 1 4 1 5 1 6

T I M E

IN M I N U T E S

FIGURE

3

VARIATION

OF

TEMPERATURE

AT

THERMO-

C O U P L E

DURING INDIVIDUAL

T E S T S

ON

.

_I I I I I I I I I I I I I I 1

-

-

'TEST NO. 1

-

> I I I I I I I I I I I I I I I TlME IN MINUTES 0 1 2 3 4 5 6 7 8 9 1 0 1 1 1 2 1 3 1 4 1 5 1 6 I I I I 1 I I I I I I I I I I T 1 4 5 0

-

TEST NO. 1

-

-

1 3 5 0 I I I I I I I I I I I I I I I L ni

.

W I I I I I I 1 I I I I I I I I

%

1 4 0 0

-

Ti?

-

4

-

TEST NO. 2

_-

I I I I I . I 1 I I I I I I I I 0 1 2 3 4 5 6 7 8 9 1 0 1 1 1 2 1 3 1 4 1 5 1 6 T l M E I N M I N U T E S FIGURE

5

VARIATION OF TEMPERATURE AT THERMOCOUPLE

DURING INDIVIDUAL T E S T S ON ASBESTOS

PAPER. DBR. REPORT 96. W u 3 1 4 5 0 - I- 1 4 0 0 W a 1 3 5 0 1 I I I I I I I I I I I I I I I TEST NO. 2

-

-

-&

I I I I I I I I I I I I I I I I 2 W I- I I I I I I I I I I I I I I I

-

TEST NO. 3

-

-

'""0

k

5

b

0 11 1 h 1; 1 h 1; 1 6 T l M E IN M I N U T E S FIGURE 4

VARIATION OF TEMPERATURE AT THERMOCOUPLE

DURING INDIVIDUAL T E S T S O N PAPER- BACKED

I I 1 I I 1 I I I I I I I I I

-

A

-

I I I I I I I I I I I I I I I 0 1 2 3 4 5 6 7 8 9 1 0 1 1 1 2 1 3 1 4 1 5 1 6 T l M E IN MINUTES FIGURE 6

TEMPERATURE AT THERMOCOUPLE DURING

TESTS ON PLASTERBOARD (AVERAGE OF 3

OR 4 REPEAT TESTS) A - CONDITIONED A T 140'F B - CONDITIONED AT 212 'F; C - CONDITIONED OVER CA CL 2 n I I I I I 1 I I I I I V

-

-

-

- - - _ - _ - - - _ _ _ _ _ _ _ - - -

-

---

---

-

I W I I I I I I I I I I I I I I 1 I- 0 1 2 3 4 5 6 7 8 9 10 11 1 2 1 3 1 4 1 5 10 TIME IN MINUTES FIGURE 7

TEMPERATURE AT THERMOCOUPLE DURING

T E S T S ON MINERAL WOOL (AVERAGE OF

3 OR 4 REPEAT T E S T S )

A

-

CONDITIONED A T 140 F; B

-

CONDITIONED A T 212 * F; C - CONDITIONED OVER C A C L

FIGURE 8 T I M E I N MINUTES

TEMPERATURE A T THERMOCOUPLE DURING

TESTS ON G L A S S WOOL (AVERAGE OF 3

OR 4 REPEAT T E S T S )

A

-

PAPER

-

BACKED SPECIMEN C O N D I T I O N E D A T 140 'F

B

-

UNBACKED I I I I 11 212 OF

C

-

I I I I _{I I OVER CA C L ~}