thermal insudcfvfsdfdsfsdlation for pipe

7/28/2019 Thermal Insudcfvfsdfdsfsdlation for Pipe

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F i r e T ests onT h er m a l I n su l a t i o n Syst em s o r P i pes

DURBIN H. WAY, S F P E , and CARLOS J. HILADOUnion Carbide Corporation

Thermal insulation systems used to conserve heat and refrigerationin industrial plants should be evaluated in the same manner asconstruction materials insofar as fire performance is concerned.The aut}mrs report a wide range of behavior for several insulationsystems examined in large-scale fire tests .

T HERMAL insulation systems play an important part in the efficientoperation of industrial plants because of the appreciable value ofenergy employe d in heating and refrigeration. Because their use is wide-spread in manufacturing facilities, they tend to be among the first ma-terials subjected to flame impin gemen t in an accidental fire. Their per-formance under fire conditions, therefore, is of significant concern fromthe viewpoints of fire hazard, fire protection, and fire damage.A L O O K A T T H E R M A L I N S U L A T I O N S Y S T E M S

Thermal insulation systems consist of three components: the thermalinsulation material, which has the function of effectively reducing heattransfer; the protective material, which has the function of preventing re-duction in the efficiency of the the rmal insulation by the envir onmen t andby mechanical abuse; an d the securement material, which has the fun ctionof keeping the entire system in place.

At the very least, a thermal insulation system should present no sig-nificant fire hazard: th at is, it should not cont ribu te significantly either asfuel for the fire or as a means of prop agati ng the fire. It would be moredesirable if it provided some measure of protection for the insulated pipesor vessels, preferably at least one hour before pipe or vessel wall temper-atur es reach a critical level. Ideally, it should survive the fire un dam age dby either direct flame impingement or the impact of quenching water.

A thermal insulation system is judged as presenting a fire hazard if iteither increases the sev erity of the fire in its existing location, or propa gatesthe fire to adjacen t areas. Fire hazard can result from fuel contributio nby a combustible thermal insulation material, from flame spread on theprotective material, or from severe failure of the securement material.

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272 F i r e T e c h n o l o g yA t h e r m a l i n s u la t i o n m a t e r i a l is j u d g e d a s p r o v id i n g f ir e p r o t e c t i o n i fi t r e t a r d s t h e t e m p e r a t u r e r is e o f t h e i n s u l a t e d p i p e o r v e ss e l f r o m r e a c h i n g

a f a i l u r e p o i n t f o r a t l e a s t 6 0 m i n . A f a i l u r e p o i n t o f 1 ,0 0 0 ~ F w a s s e l e c t e df o r t w o r e a s o n s - s te e l r a p i d ly l o se s i ts s t r e n g th a t t e m p e r a t u r e s a b o v et h i s le v el , a n d a t o r n e a r t h i s t e m p e r a t u r e , m a n y r e a c t i v e c h e m i c a l s d e -c o m p o s e w i t h e x p l o s iv e v i o le n c e.

A t h e r m a l i n s u l a ti o n s y s t e m is j u d g e d t o h a v e s u f f e r e d f ir e d a m a g e i fi t c a n n o t b e r e t u r n e d t o s e r v ic e a t i t s or i g in a l e f f ic i e n cy w i t h o u t r e p l a c e-m e n t o f o n e o r m o r e o f it s c o m p o n e n t s .

T h e r e l a t i v e s i g n if i c an c e o f t h e s e t h r e e v i e w p o i n t s s h o u l d b e c o n s i d e r e d .F i r e h a z a r d is de f i n it e ly u n d e s ir a b l e ; t h e u s e o f h a z a r d o u s m a t e r i a l s o fc o n s t r u c t i o n r e q u i r e s t h e n e c e s s a r y a d d it i o n a l s a f e t y m e a s u r e s , s u c h a sf i r e s t o p s a n d f i r e b r e a k s , a n d in c r e a s e d p r o t e c t i o n e q u i p m e n t . F i r e p r o -t e c t i o n i s d e s i r a b le , b u t i n m a n y c a s e s , it is m o r e e c o n o m i c a l l y p r o v i d e d b yw a t e r s p r a y a n d o t h e r s y s te m s . T h e f i r e p r o t e c t i o n p r o v i d e d i n a s t r u c t u r eo f t e n a f f o r d s s u f f ic i e n t p r o t e c t i o n f o r v e ss e l s a n d p i p in g . I n c h e m i c a lp r o c e s s p l a n ts , u n i t s h a n d l i n g r e a c t i v e c h e m i c a ls r e q u ir e t h e m a x i m u mf i re p r o t e c t i o n a n d t h u s c a l l f o r f i r e - p r o t e c t i v e i n s u l a t io n , b u t s u c h u n i t su s u a l l y c o m p r i s e le s s t h a n 1 0 p e r c e n t o f i n s u l a t i o n a p p l i c a t i o n s i n a n yp a r t i c u l a r p l a n t. F i r e d a m a g e is a n i m p o r t a n t c o n s i d e r a t i o n b e c a u s e o ft h e n e e d t o r e s u m e p r o d u c t i o n a s s o o n a s p o s s i b l e a f t e r a f i r e , a s w e l l a s t h ec o s t o f r e p l a c i n g t h e i n s u l a ti o n .

T h e b a s i c f u n c t i o n o f a th e r m a l i n s u l at i o n s y s t e m is to r e d u c e t h e f lo wo f h e a t a s e f f e c t i v e l y a s p o s s i b l e o v e r a l o n g e n o u g h s e r v i c e l i f e t o p r o v i d ea s a t i s f a c t o r y r e t u r n o n in s u l a t io n i n v e s t m e n t . G o o d f ir e p e r f o r m a n c e i sn o t a s u b s t i t u t e f o r i n s u l a t i n g e f f i c ie n c y ; i f i t w e r e , o u r i n d u s t r i a l p l a n t sw o u l d b e i n s u l a te d w i t h n o n c o m b u s t i b l e m a t e r i a ls t h r o u g h o u t . I n g e n e ra l,a n e f fi ci en t t h e r m a l i n s u l a t io n s y s t e m t h a t m a y r e q u i r e a d d i t i o n a l e x p e n s ef o r fi re p r o t e c t i o n i s p r e f e r a b l e t o a n i n e f fi c ie n t s y s t e m o f f e r i n g o n l y f ir ep r o t e c t i o n a d v a n t a g e s .

T H E O R E T I C A L C O N S I D E R A T I O N SA f ir e e x p o s u r e t e s t h a s i t s p r i n c i p a l v a l u e i n s i m u l a t i n g t h e c o n d i t i o n s

t h a t w o u l d p r o b a b l y e x i s t i n a n a c c i d e n t a l f ir e. I n i n d u s t r i a l p l a n t s , p a r -t i c u l a r ly i n t h e c h e m i c a l p r o c es s i n d u st r ie s , a s u b s t a n t i a l p r o p o r t i o n o fa c c i d e n t a l f ir e s i n v o l v e b u r n i n g l i q u id s , s o t h a t v e s s e l s a n d p i p i n g t e n d t ob e e x p o s e d t o d ir e c t f l am e im p i n g e m e n t . P e r h a p s t h e m o s t v i v i d d e s c ri p -t i o n o f a t y p i c a l s e v e r e f ir e w o u l d b e "a s e a o f f i r e " a t t h e b a s e o f a st il lc o l u m n o r b e n e a t h a p i p e r a c k .

T h e r e q u i r e m e n t s o f a f ir e e x p o s u r e t e s t w o u l d , t h e r e f o r e , i n c l u d e p r o -v i s i o n s f o r d i r e c t f l a m e i m p i n g e m e n t , f o r a f i re s o u r c e o f s u b s t a n t i a l a r e a ,f o r d i r e c t im p i n g e m e n t o f h o t c o m b u s t i o n g a s e s, f o r a r a p i d r a t e o f t e m p e r -a t u r e r i s e a t t h e s t a r t o f t h e f ir e , a n d f o r g e n e r o u s a c c e s s o f a i r. T h e s e c o n -d i t io n s w e r e p r o v i d e d b y b u r n i n g g a s o li n e in a la r g e o p e n p a n .

T h e e x p o s u r e f ir e s h o u l d p r o v i d e a m a x i m u m h e a t r a t e , w h i c h isa c h i e v e d b y a c o n s i d e r ab l e th i c k n e s s o f f la m e . T h i c k n e s s e s a p p r o a c h i n g


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T h e r m a l I n s u l a t i o n S y s t e m s 2733 f t a r e d e s i r a b l e t o r e d u c e r a d i a t i o n l o s se s t o t h e o u t s i d e . I n m o s t a c c i -d e n t a l f ir e s, m a x i m u m h e a t r a t e s a r e n o r m a l ; t h u s , t e s t f ir e s o f 3 - f t th i c k -n e s s r e p r e s e n t f ie l d e x p e r ie n c e .

A P P A R A T U ST h e e q u i p m e n t u s e d c o n s i s t e d o f t h e f o l lo w i n g : ( 1 ) a s t e e l f u e l p a n

m e a s u r i n g 7 f t 6 i n. l o n g , 4 f t w i d e , a n d 1 f t 6 i n. d e e p ; ( 2) a s t e e l p i p e s u p -p o r t r a c k t o h o l d f i v e 2 0 - f t l e n g t h s o f 3- in . I P S p i p e ; ( 3) f i v e 2 0 - f t l o n g ,3 - in . I P S , s c h e d u l e 4 0 c a r b o n s t e e l p i p e s p e r t e s t ; (4 ) c h r o m e l - a l u m e lt h e r m o c o u p l e w i r e w i t h p o r c e l a i n i n s u l a t o r s a n d c o n n e c t i o n s ; (5 ) a m u l t i -p o i n t r e c o rd i n g p o t e n t i o m e t e r ( te n p o i n ts m i n i m u m , t w o f o r e a c h p ip e ) ;( 6) f u el s u p p l y a n d c o n t r o l e q u i p m e n t ; a n d ( 7) w a t e r s u p p l y a n d e q u i p -m e n t f o r w a t e r s t r e a m a n d w a t e r s p r a y a p p l i c at io n .

E a c h 2 0 - f t t e s t p i p e w a s c u t a t t h e c e n t e r o n a 3 0 ~ a n g l e t o l o n g i t u d i n a lc e n t e r l i n e t o f o r m t w o s e c ti o n s . A c h r o m e l - a l u m e l t h e r m o c o u p l e w a s in -s t a l l e d o n t h e i n s id e w a l l o f e a c h s e c t i o n a t p o i n t s t h a t l o c a t e d t h e t h e r m o -c o u p l es I 8 0 ~ a p a r t a n d 1 0 f t f r o m e i t h e r e n d w h e n t h e p i p e w a s r e a s s e m b l e d .T h e t w o s e c t io n s w e r e w e l d e d t o g e t h e r t o r e f o r m t h e o r i g i n al 2 0 - f t lo n gt e s t p i p e .F i v e p i p e s w e r e p l a c e d o n t h e s u p p o r t r a c k i n t h e s a m e h o r i z o n t a lp l a n e , s p a c e d o n 1 6 -i n. c e n t e rs , s o t h a t t h e t h e r m o c o u p l e s w e r e c e n t e r e do v e r t h e f u el p a n . T h e t h e r m o c o u p l e s w e r e c h ec k e d f o r c o n t i n u i t y , a n dt h e l e a d w i r e s w e r e c o n n e c t e d t o t h e p o t e n t i o m e t e r . T h e o p e n e n d s o f e a c hp i p e w e r e p a c k e d w i t h w h i t e g l a ss w o o l i n s u l a ti o n t o p r e v e n t a i r m o v e m e n tt h r o u g h t h e p ip e s . T h e f u e l p a n w a s c h a r g e d w i t h w a t e r u n t il t h e w a t e rl e v e l w a s 1 f t 8 in . b e l o w t h e h o r i z o n t a l c e n t e r l in e s o f t h e t e s t p i p e s .

S P E C I M E N P R E P A R A T I O NE a c h s p e c i m e n c o n s i s te d o f o n e t e s t p ip e o n w h i c h a c o m p l e t e t h e r m a l

i n s u l at i o n s y s t e m w a s i n st a ll e d. T h e i n s u l a ti o n w a s a p p l i e d t o th e m i d d l e1 2 l in e a r f e e t o f t h e t e s t p ip e . T h r e e a p p l i c a t io n m e t h o d s w e r e u s e d f o rt h e t h e r m a l i n s u l a t i o n m a t e r i a l .

9 F o r s i n g l e - l a y e r m a s s - t y p e a p p l i c a t i o n , 3 6 - in . l o n g s e c t i o n s o f s e m i -c y l in d r i c a l p ip e i n s u l a ti o n w e r e a p p l ie d w i t h a l l j o i n ts t i g h t l y b u t t e d a n df i tt e d . T h e b u t t e d g e s a n d e n d s o f s o m e l o w - t e m p e r a t u r e i n s u l a t i o n s w e r e" b u t t e r e d " w i t h j o in t s e a l er b ef o r e a p p l ic a t i o n . T h e i n s u l a t io n w a s s e-c u r e d t o t h e p i p e w i t h 1 6 - g a g e s t a i n l e s s s t e e l w i r e i n m o s t c a s e s , t h e w i r ea p p l i e d o n 1 8 - in . c e n t e r s ( 9 in . f r o m e n d s o f s e c ti o n s ) .

9 F o r d o u b l e - l a y e r m a s s - t y p e a p p l i c a t i o n , 3 6 -i n. l o n g s e c t i o n s o f s e m i -c y l i n d r i c a l p i p e i n s u l a t i o n w e r e a p p l i e d in t w o l a y e rs . T h e s e c t i o n s o f t h ei n n e r l a y e r w e r e a p p l i e d t o t h e te s t p i p e w i t h e n d j o i n t s s ta g g e r e d . O u t e rl a y e r s e c ti o n s w e r e a p p l ie d w i t h t h e l o n g i t u d i n a l a n d e n d , b u t t j o i n t s o f f s e tf r o m t h e i n n e r l a y e r j o i n t s a m i n i m u m o f 2 in . A l l j o i n t s w e r e t i g h t l yb u t t e d a n d f it te d . F o r s o m e l o w - t e m p e r a t u r e i n s u l at io n , t h e b u t t e d g e sa n d e n d s o f t h e s e c t io n s o f t h e o u t e r l a y e r w e r e " b u t t e r e d " w i t h j o i n ts e a l e r b e f o r e a p p l i c a t i o n . I n m o s t c a s e s , t h e i n n e r la y e r w a s s e c u r e d t o


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274 Fire Tech nol ogythe pipe with 16-gage stainless steel wire, and the outer layer was securedby ~- in . wide, 0.020-in. thick stainless steel bands. The wir e and thebands were applied on 18-in. centers (9 in. from ends of sectio ns).

9 For reflective insulation, prefa bricate d un its 24 in. long were applied.Ea ch u nit was fabricated in two semicylindrical sections and was com-posed of reflective sheets spaced and reinforced by separators to form iso-lated chambers. One circumferential edge of each unit and t he long itudinaledges of one section were extended to provide overlap and watershed.These units of insulation were secured by ~-in. wide, 0.020-in. thick stain-less steel bands applied on 12-in. centers starting 6 in. from ends of eachu I l i t .

The protective material for each thermal insulation system was eithera jack et (such as metal sheet, felt roofing sheet, or pol yvin yl chlorid e sheet)or a mastic (based on asphalt or polyvin yl acetate formulation s). In somecases the mastic was reinforced with glass-fabric mesh or Dynel* fabricmesh.

T E S T P R O C E D U R EGasoline was fed into the fuel pan until the water surface was covered.

The fuel was ignited so that the five test pipes were fully exposed simul-taneo usly to the fire. The fuel flow into th e pan was controlled so th at thetemperature in a bare pipe would coincide with the NFPA No. 251 stand-ard fire tem pe ra tu re curve (1,000 ~ F in 5 min , 1,300 ~ F in 10 mi n, 1,550 ~ Fin 30 rain, and 1,700 ~ F in 60 min). Experien ce with t he te st sho wed t ha tthis could be achieved by controlling the fuel at a rate of I gpm for th e first5 rain exposure, 1.8 gpm for the next 10 min exposure, and 2.5 gpm for theremainder of the exposure.

After 1 hour of fire exposure, durin g which period t emp era tur es wererecorded as a function of time, the fuel was shut off and the fire allowedto go out. Eac h test pipe was inspected and th e observatio ns recorded.After 16 mill, the fuel was reignited and burned for 5 min to reestablishfull exposure conditions. The fuel was then s hut off and water at a rate of75 gpm was applied to the insulation in a straight stream t hro ugh a 1 ~-i n.Elk har t Mys ter y nozzle from a distance of 60 ft for 1~ min. The waterapplication was then changed from a straight stream to a spray and wascontinued until the residual fuel burned out. A second inspection of eachtest pipe was made an d observations recorded. The insulation was removedfrom each pipe, section by section. Th e effect of heat a nd wa te r on eachsection was recorded.

T E S T R E S U L T SThe data that were recorded and the observations that were made dur-

ing and after the tests were analyzed by grouping the results to give gen-eralized conclusions on the behavior of generic materials and systems when

* T r a d e n a m e o f t h e U n i o n C a r b i d e C o r p o r a t i o n .


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T h e r m a l I n s u l a t i o n S y s t e m s 275e x p o s ed t o fi re . T h e r e p o r t e d v a r i a ti o n s i n t e m p e r a t u r e w e r e t h e r e su l t ind i ff e re n c es b e t w e e n m a t e r i a l s o f v a r io u s m a n u f a c t u r e r s .T h e t h e r m a l in s u l a ti o n s y s t e m s a r e d i sc u s se d i n t h r e e g r o u p s - h i g ht e m p e r a t u r e i n s u l a ti o n s y s t e m s e m p l o y i n g t h e r m a l i n s u l a t i o n m a t e r ia l s ,s u c h a s c a l c i u m s i l ic a t e, m a g n e s i a , d i a t o m a c e o u s e a r t h , a s b e s t o s f ib e r s,a n d p e r li t e; l o w t e m p e r a t u r e i n s u la t i o n s y s t e m s e m p l o y i n g m a t e r ia l s , s u c ha s c e l l u l a r g l a s s , c e l l u l a r s i l i c a , v e g e t a b l e c o r k , g l a s s f i b e r , a n d c e l l u l a rp o l y s t y r e n e ; a n d w i d e - r a n g e i n s u la t i o n s y s t e m s e m p l o y i n g m a t e ri a l s, s u c ha s r i g i d c e l l u l a r p o l y u r e t h a n e , w h i c h h a v e a p p l i c a t i o n s a t l o w , m o d e r a t e ,a n d h i g h t e m p e r a t u r e s .O n t h e b a s i s o f t h e i n s u l a t i o n s y s t e m s ' p e r f o r m a n c e i n fi re a s r e l a t e d t oe x p e r i e n c e , t h e f i r e h a z a r d w a s j u d g e d a s e i t h e r n o n e o r u n d e s i r a b l e ; f i r ep r o t e c t i o n w a s j u d g e d a s e i t h e r i n s i g n i f i c a n t , s o m e , s u b s t a n t i a l , o r d e s i r -a b le ; a n d f i r e d a m a g e w a s j u d g e d a s s e v er e r e qu i r in g c o m p l e t e r e p l a c e m e n to f t h e i n s u l a t io n s y s t e m , m o d e r a t e r e q u i r in g p a r t i a l r e p l a c e m e n t , a n d l i gh tr e q u i r in g r e p l a c e m e n t o f t h e w e a t h e r o r v a p o r b a r r i e r on l y. T h e r m a li n s u l a ti o n s y s t e m s t h a t e x h i b i te d u n d e s i r a b l e fi re h a z a r d a r e n o t u s e d i nU n i o n C a r b i d e C o r p o r a t i o n p la n ts . F i r e p r o t e c ti o n a n d f ir e d a m a g e c o n -s i d e r a t i o n s i n v o l v e d r e l a t i v e e c o n o m i c s a n d e f f e c t iv e n e s s o f ex i s t i n g a n da d d i t i o n a l f ir e p r o t e c t i o n e q u i p m e n t a n d s a f e t y d e v i c es , a n d d e c i s i o n s r e -g a r d i n g u s e a r e b a s e d o n t h e f a c t o r s p r e s e n t i n a p a r t i c u l a r a p p l i c a t i o n .

H I G H T E M P E R A T U R E I N S U L A T I O N S Y S T E M SA t h e r m a l i n s u l a t i o n s y s t e m c o n s i s t in g o f a s i n g l e l a y e r o f c a l c i u ms i li c a te , 1 i n. t h i c k , a n d a p o l y v i n y l a c e t a t e w e a t h e r b a r r i e r m a s t i c g a v ei n t e r n a l p i p e t e m p e r a t u r e s f r o m 2 50 ~ F t o 6 0 0 ~ F a f t e r 3 0 m i n o f fi r e e x-p o s u r e , a n d f r o m 4 8 5 ~ F t o 1 ,1 00 ~ F a f t e r 6 0 m i n o f e x p o s u re . S h r i n k a g ec a u s e d c r a c k s , l o n g i t u d i n a l a n d c i r c u m f e r e n t i a l , ~ t o ~ i n. w i d e a t t h ej o i n t s b e t w e e n s e c ti o n s , e x p o s i n g t h e p i p e s t o f la m e i m p i n g e m e n t . L o n g i -t u d i n a l s h r i n k a g e w a s a p p r o x i m a t e l y I i n . f o r e v e r y 36 - in . s e c ti o n , a n dc i r c u m f e r e n t i a l s h r i n k a g e w a s a p p r o x i m a t e l y 8 9 i n. C r a c k i n g w a s a p -p a r e n t o n t h e e x te r i o r s u r fa c e . T h e i n s u l a t i o n w a s w a t e r - s o a k e d a f t e rb e i n g s u b j e c t e d t o fi re , a n d s t r u c t u r a l s t r e n g t h w a s i m p a i r e d . T h i s t h e r m a li n s u l a ti o n s y s t e m w a s j u d g e d t o p r e s e n t n o f ir e h a z a r d a n d t o p r o v i d e s u b -

s t a n t i a l f i re p r o t e c t i o n . F i r e d a m a g e w a s s e v e r e .A t h e r m a l i n s u l a t i o n s y s t e m c o n s i s t in g o f t w o l a y e r s o f c a l c i u m s i l ic a t e ,2 F~ in . t o t a l t h i c k n e s s , a n d a p o l y v i n y l a c e t a t e w e a t h e r b a r r i e r m a s t i cg a v e i n t e r n a l p i p e t e m p e r a t u r e s n o t e x c e e d i n g 18 0 ~ F a f t e r 3 0 r a i n a n dn o t e x c e e d i n g 22 5 ~ F a f t e r 6 0 m i n . S h r i n k a g e c a u s e( ] l o n g i t u d i n a l a n dc i r c u m f e r e n t i a l c r a c k s t h r o u g h t h e o u t e r l a y e r o f i n s u la t i on . C i r c u m f e r -e n t i a l c r a c k s w e r e ~ t o 1 i n. w i d e , a n d l o n g i t u d i n a l c r a c k s w e r e ~ t oi n. w i de ; t h e s e c r a c k s o c c u r r e d a t t h e j o i n t s b e t w e e n s e c t io n s . T h e i n n e rl a y e r s h o w e d s l i g ht s h r i n k a g e w i t h t h e r e s u l t i n g j o i n t c r a c k s n o t e x c e e d i n gi n. in w i d t h . B e c a u s e o f t h e d o u b l e - l a y e r , s t a g g e r e d j o i n t c o n s t r u c t i o n ,t h e p ip e s w e r e n o t e xp o s e d t o fl a m e i m p i n g e m e n t . T h e s t r u c t u r a l s t r e n g t ho f t h e o u t e r l a y e r w a s i m p a i r e d , a n d e x p o s e d in s u l a t io n w a s w a t e r - s o a k e d .


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276 F i r e T e c h n o l o g yT h i s t h e r m a l i n s u l a t io n s y s t e m w a s ju d g e d t o p r e s e n t n o fi re h a z a r d a n d t op r o v i d e d e s i r a bl e f ir e p r o t e c ti o n . F i r e d a m a g e w a s m o d e r a t e .

A t h e r m a l i n s u l a t i o n s y s t e m c o n s i s t i n g o f a s i n g le l a y e r o f m a g n e s i a ,1 in . th i c k , a n d a p o l y v i n y l a c e t a t e w e a t h e r b a r r i e r m a s t i c g a v e i n t e r n a lp i p e t e m p e r a t u r e s o f 2 9 3 ~ F a f t e r 3 0 ra i n a n d 7 5 0 ~ F a f t e r 6 0 m i n . S e v e r es h r i n k a g e c r a c k s e x p o s e d t h e p i p e to fl a m e i m p i n g e m e n t . T h e i n s u l a t io nw a s s e v e r e l y d a m a g e d , a n d m o s t o f it w a s d is l o d g e d f ro m t h e p i p e w h e ns u b j e c t e d t o t h e w a t e r a p p l ic a t io n s . T h e r e m a i n i n g i n s u la t i o n w a s s o g g ya n d t h o r o u g h l y w a t e r s o a k e d . T h i s t h e r m a l i n s u la t i o n s y s t e m w a s j u d g e dt o p r e s e n t n o f ir e h a z a r d a n d t o p r o v i d e d e s i r a b l e f ir e p r o t e c t i o n . F i r ed a m a g e w a s s ev e r e.

A t h e r m a l i n s u la t io n s y s t e m c o n s i st in g o f t w o l a y e r s o f m a g n e s i a ,2 8 9 in . t o t a l t h ic k n e s s , a n d a p o l y v i n y l a c e t a t e w e a t h e r b a r r i e r m a s t i cg a v e i n t e r n a l p i p e t e m p e r a t u r e s o f 13 0 ~ F a f t e r 3 0 m i n a n d 1 8 0 ~ F a f t e r 6 0m i n . T h e o u t e r la y e r o f i n s u l at i o n d e v e l o p e d s h r in k a g e c r a ck s , l o n g i t u d i n a lc r a c k s f r o m 8 9 t o 1 in . w i d e a n d c i r c u m f e r e n t i a l c r a c k s a b o u t ~ i n. w i de ,a t t h e j o in t s b e t w e e n s e c ti o ns . T h e o u t e r la y e r o f i n s u l a ti o n h a d d e -t e r i o r a te d , b u t t h e in n e r l a y e r a p p e a r e d s t r u c t u r a l l y s o u n d . B e c a u s e oft h e d o u b l e - l a y e r , s t a g g e r e d - j o i n t c o n s t r u c t io n , t h e p i p e w a s n o t e x p o s e d t of l a m e i m p i n g e m e n t . T h e s t r u c t u r a l s t r e n g t h o f t h e o u t e r l a y e r w a s s o i m -p a i r e d t h a t s o m e o f i t w a s s w e p t a w a y b y t h e w a t e r a p p l i c a t i o n , a n d t h er e m a i n i n g i n s u la t io n w a s s o g g y a n d t h o r o u g h l y w a t e r - s o a k e d . T h i s t h e r m a li n s u l a ti o n s y s t e m w a s j u d g e d t o p r e s e n t n o f ir e h a z a r d a n d t o p r o v i d ed e s i r a b l e f ir e p r o t e c t i o n . F i r e d a m a g e w a s s e v e r e .A t h e r m a l i n s u la t i o n s y s t e m c o n s i s ti n g o f a s i ng l e la y e r o f d i a t o m a c e o u se a r t h , 1 in . t h i ck , a n d p o l y v i n y l a c e t a t e w e a t h e r b a r r i e r g a v e i n t e r n a l p i p et e m p e r a t u r e s n o t e x c e e d i n g 3 7 5 ~ F a f t e r 3 0 m i n , a n d f r o m 5 8 8 ~ F t o 7 1 0 ~F a f t e r 6 0 m in . S h r i n k a g e c a u s e d l o n g i t u d i n a l a n d c i r c u m f e r e n t i a l c r a c k s

t o ~ i n. w i d e a t t h e j o i n t s b e t w e e n s e c t io n s , e x p o s i n g t h e p i p e s t of l a m e i m p i n g e m e n t . P i e c e s o f i n s u l a ti o n w e r e d i s l o d g e d b y t h e s t r e a m o fw a t e r , a n d a l l i n s u la t i o n w a s w a t e r - s o a k e d . S t r u c t u r a l s t r e n g t h w a s s oi m p a i r e d t h a t t h e i n s u la t io n f r a c t u r e d a n d c r u m b l e d w h e n h a n d l e d . T h i st h e r m a l i n s u la t i o n s y s t e m w a s j u d g e d t o p r e s e n t n o fi re h a z a r d a n d t op r o v i d e d e s i r a b l e f ir e p r o t e c t io n . F i r e d a m a g e w a s s e ve r e .

A t h e r m a l i n s u la t i o n s y s t e m c o n s i s ti n g o f t w o l a y e r s o f d i a t o m a c e o u se a r t h , 2 8 9 i n. t o t a l t h i c k ne s s , a n d a p o l y v i n y l a c e t a t e w e a t h e r b a r r i e r m a s t i cg a v e i n t e r n a l p i p e t e m p e r a t u r e s n o t e x c e e d in g 1 7 0 ~ F a f t e r 3 0 m i n , a n d n o te x c e e d in g 2 60 ~ F a f t e r 6 0 m i n . S h r i n k a g e c a u s e d ~ - i n . w i d e l o n g i t u d i n a la n d c i r c u m f e r e n t i a l c r a c k s t h r o u g h t h e o u t e r l a y e r o f i n s u l a t i o n a t t h ej o i n t s b e t w e e n se c ti o n s. T h e i n n e r l a y e r s h o w e d l o n g i t u d i n a l c r a c k s a b o u t~ 6 i n. w i d e . B e c a u s e o f t h e d o u b l e - l a y e r , s t a g g e r e d - j o i n t c o n s t r u c t i o n , t h ep i p e s w e r e n o t e x p o s e d t o f la m e i m p i n g e m e n t . T h e s t r u c t u r a l s t r e n g t h o ft h e o u t e r l a y e r o f in s u l a ti o n w a s i m p a i r e d , b u t t h e e f f ec t o f q u e n c h i n gw a t e r w a s c o n s i d e r e d n e gl ig ib le . T h i s t h e r m a l i n s u l a t io n s y s t e m w a sj u d g e d t o p r e s e n t n o f ir e h a z a r d a n d t o p r o v i d e d e s i r a b le f ir e p r o te c t i o n .F i r e d a m a g e w a s m o d e r a t e .


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T h e r m a l I n s u l a t i o n S y s t e m s 277A t h e r m a l i n s u l a t i o n s y s t e m c o n s i s t i n g o f a s in g l e l a y e r " of a s b e s t o sf i b er s , 1 i n. th i c k , a n d a p o l y v i n y l a c e t a t e w e a t h e r b a r r i e r m a s t i c g a v e

i n t e r n a l p i p e t e m p e r a t u r e s o f 2 9 0 ~ F a f t e r 3 0 r a in a n d 7 1 0 ~ F a f t e r 6 0 r a in .S h r i n k a g e c a u s e d l o n g i tu d i n a l a n d c i r c u m f e r e n t i a l c r ac k s a b o u t 89 in.w i d e a t t h e j o i n t s b e t w e e n s e c t i o n s , e x p o s i n g t h e p i p e t o f l a m e i m p i n g e -m e n t . T h e e f f e c t o f t h e q u e n c h i n g w a t e r w a s c o n s id e r e d n e g li g ib l e , b u tt h e i n su l a ti o n h a d c h a r r e d a n d t u r n e d b l a c k a n d f r a c t u r e d a n d c r u m b l e dw h e n h a n d l ed . T h i s t h e r m a l i n s u l a t io n s y s t e m w a s j u d g e d t o p r e s e n t nof ir e h a z a r d a n d t o p r o v i d e d e s i r a b l e f ir e p r o t e c t i o n . F i r e d a m a g e w a ss e v e r e .

A t h e r m a l i n s u l a t i o n s y s t e m c o n s i s t i n g o f t w o l a y e r s o f a s b e s t o s f i be r s ,2 ~ in . t o t a l th i c kn e s s , a n d a p o l y v i n y l a c e t a t e w e a t h e r b a r r i e r m a s t i cg a v e i n t e r n a l p i p e t e m p e r a t u r e s o f 1 30 ~ F a f t e r 3 0 r a in a n d 2 0 0 ~ F a f t e r6 0 m i n . S h r i n k a g e c a u s e d l o n g i t u d i n a l a n d c i r c u m f e r e n t i a l c r a c k s le s st h a n ~ 6 in . w i d e t h r o u g h t h e o u t e r l a y e r o f i n s u la t io n a t t h e j o i n t s b e t w e e ns e c ti o ns . N o c r a c k s w e r e a p p a r e n t i n t h e in n e r l a y e r . B e c a u s e o f t h ed o u b l e - la y e r , s t a g g e r e d - jo i n t c o n s t r u c t i o n , t h e p i p e w a s n o t e x p o s e d t of l a m e i m p i n g e m e n t . T h e s t r u c t u r a l s t r e n g t h o f t h e o u t e r la y e r w a s im -p a i r e d , b u t t h e e f f e c t o f t h e q u e n c h i n g w a t e r w a s c o n s i d e r e d n e g l ig i b le .T h i s t h e r m a l i n s u la t io n s y s t e m w a s ju d g e d t o p r e s e n t n o fi re h a z a r d a n dt o p r o v i d e d e s ir a b l e f ir e p r o t e c ti o n . F i r e d a m a g e w a s m o d e r a t e .

A t h e r m a l i n s u l a t i o n s y s t e m c o n s i s t i n g o f a s in g l e l a y e r o f a s b e s t o sf i b e r a n d p e r l i t e, I i n . t h i c k , a n d a p o l y v i n y l a c e t a t e w e a t h e r b a r r i e r m a s t i cg a v e i n t e r n a l p i p e t e m p e r a t u r e s o f 2 90 ~ F a f t e r 3 0 ra i n a n d 5 1 5 ~ F a f t e r6 0 r a in . L o n g i t u d i n a l a n d c i r c u m f e r e n t i a l s h r i n k a g e c r a c k s a b o u t ~ i n.w i d e o c c u r r e d a t t h e j o i n t s b e t w e e n s e c t i o n s , e x p o s i n g t h e p i p e t o f l a m ei m p i n g e m e n t . T h e e f fe c t o f t h e q u e n c h i n g w a t e r w a s c o n s i d e re d n e g li gi b le .T h e i n s u la t i on r e m a i n e d c o m p l e t e l y i n t a c t a n d a p p e a r e d t o r e t a in i t ss t r u c t u r a l s t r e n g t h . T h i s t h e r m a l i n s u l a t io n s y s t e m w a s j u d g e d t o p r e s e n tn o fi re h a z a r d a n d t o p r o v i d e d e s i r a b le fi re p r o t e c ti o n . F i r e d a m a g e w a sl igh t .A t h e r m a l i n s u la t io n s y s t e m c o n s i s ti n g o f t w o l a y e r s o f a s b e s t o s f i b era n d p e r l it e , 2 ~ i n. t o t a l t h ic k n e s s , a n d a p o l y v i n y l a c e t a t e W e a t h e r b a r r i e rm a s t i c g a v e i n t e r n a l p i p e t e m p e r a t u r e s o f 1 40 ~ F a f t e r 3 0 m i n . a n d 2 0 0 ~ Fa f t e r 6 0 r ai n. L o n g i t u d i n a l a n d c i r c u m f e r e n t i a l sh r i n k a g e c r a c k s a b o u ti n . w i d e o c c u r r e d a t t h e j o i n t s b e t w e e n s e c t i o n s i n t h e o u t e r l a y e r o fi n su l a ti o n . N o c r a c k s w e r e a p p a r e n t i n t h e in n e r la y e r . B e c a u s e o f t h ed o u b l e - la y e r , s t a g g e r e d - j o in t c o n s t r u c t i o n , t h e p i p e w a s n o t e x p o s e d t of l a m e i m p i n g e m e n t . T h e e f f e c t o f t h e q u e n c h i n g w a t e r w a s c o n s i d e re dn e g l i g i b l e a n d t h e i n s u l a t i o n m a t e r i a l s e e m e d t o r e t a i n i t s s t r u c t u r a ls t r e n g th . T h i s t h e r m a l i n s u l a t io n s y s t e m w a s j u d g e d t o p r e s e n t n o f ir eh a z a r d a n d t o p r o v i d e d e s i ra b l e f ir e p r o t e c t i o n . F i r e d a m a g e w a s l i g h t.A t h e r m a l i n s u la t io n s y s t e m c o n s i s t i n g o f a l u m i n u m a n d s t a i n l es s s t e e lr e f le c t iv e s h e e t s g a v e i n t e rn a l p i p e t e m p e r a t u r e s o f 41 0 ~ F a f t e r 3 0 m i na n d 9 1 0 ~ F a f t e r 6 0 m J n . T h e s y s t e m c o n s i s t e d o f fi v e s h e e t s e q u a l l ys p a c e d w i t h 2 ~ i n. t o t a l th i c k n e s s ; t h e i n n e r s h e e t w a s ~ i n. f r o m t h e


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2 78 F i r e T e c h n o l o g yp i p e s u r f a c e ; t h e i n n e r a n d o u t e r s h e e t s w e r e s ta i n l e s s s t e el , a n d t h e t h r e ei n t e r m e d i a t e s h e e t s w e r e c o r r u g a t e d a l u m i n u m . T h e s t a in l e ss s t e e l sh e e t sw e r e u n d a m a g e d ( th e o u t e r s h e e t d i s co l o re d ) . T h e c o r r u g a t e d a l u m i n u ms h e e t s m e l t e d i n t h e fi re a r ea , b u t n o n e o f t h e m o l t e n a l u m i n u m h a d l e a k e dt h r o u g h t h e st a in l e ss s t e e l o u t e r j a c k e t . T h i s t h e r m a l i n s u l a t i o n s y s t e mw a s ju d g e d t o p r e s e n t n o fi re h a z a r d a n d t o p r o v i d e d e s i r a b l e f i re p r o t e c t i o n .F i r e d a m a g e w a s s e v e r e .

L O W T E M P E R A T U R E I N S U L A T I O N S Y S T E M SA t h e r m a l i n s u l a t i o n s y s t e m c o n s i s t in g o f a s i n gl e la y e r o f c e l l u l a r g l as s ,

1 in . th i c k, a n d a p o l y v i n y l a c e t a t e w e a t h e r b a r r ie r m a s t i c g a v e i n t er n a lp i p e t e m p e r a t u r e s o f 8 1 0 ~ F a f t e r 3 0 m i n a n d 1 ,2 5 0 ~ F a f t e r 6 0 r n i n . T h ei n s u l a ti o n m a t e r i a l w a s b r o k e n i n to p i e c e s b e c a u s e o f p o o r r e s i s t a n c e t ot h e r m a l s h o c k , t h e b r o k e n p ie c e s b e i n g he l d a r o u n d t h e p i p e b y t h e w e a t h e rb a r ri e r. T h e p i p e s a g ge d . T h i s t h e r m a l i n s u l a ti o n s y s t e m w a s j u d g e d t op r e s e n t n o fi re h a z a r d b u t t o p r o v i d e s u b s t a n t i a l f ir e p r o t e c t i o n . F i r ed a m a g e w a s s e v e r e .A t h e r m a l i n s u l a t i o n s y s t e m c o n s i s t i n g o f t w o l a y e r s o f c e l l u l a r g l a s s,2 8 9 in . t o t a l th i c k ne s s , a n d a p o l y v i n y l a c e t a t e w e a t h e r b a r r i e r m a s t i cg a v e i n t e r n a l p i p e t e m p e r a t u r e s o f 2 9 0 ~ F a f t e r 3 0 m i n a n d 7 7 0 ~ F a f t e r6 0 m i n . A f t e r 5 0 m i n , a b r e a k o n t h e b o t t o m s i d e o f t h e i n s u l a t i o n r e s u l t e di n a t e m p e r a t u r e r i se o f 1 5 0 ~ F i n 5 m i n . T h e i n s u l a t i o n i n b o t h l a y e r s w a sb r o k e n i n to p i e ce s , b e c a u s e o f p o o r r e s i s t a n c e t o t h e r m a l s h o c k , a n d f e llf r o m th e p ip e w h e n d i s t u rb e d . T h i s t h e r m a l i n s u la t i o n s y s t e m w a s j u d g e dt o p r e s e n t n o f ir e h a z a r d a n d t o p r o v i d e d e s i r a b l e f i re p r o t e c t i o n . F i r ed a m a g e w a s s e v e r e .A t h e r m a l i n s u l a t i o n s y s t e m c o n s i s t in g o f a s in g l e l a y e r o f c e l lu l a rs il ic a , 1 i n. th i c k , a n d a p o l y v i n y l a c e t a t e w e a t h e r b a r r i e r m a s t i c g a v e i n-t e r n a l p i p e t e m p e r a t u r e s o f 9 1 0 ~ F a f t e r 3 0 r ai n , 1 ,0 0 0 ~ F a f t e r 3 9 m i n , a n d1 , 17 0 ~ F a f t e r 6 0 m i n . W i t h t h e e x c e p t i o n o f a f e w c r a ck s , t h e i n s u l a t i o nm a i n t a i n e d i ts s t r u c t u r a l s t r e n g t h t h r o u g h o u t t h e f ir e e x p o s u r e b u t c r a c k e df r o m th e r m a l s h o c k w h e n q u e n c h i n g w a t e r w a s a p p li e d. T h i s t h e r m a li n s u l a ti o n s y s t e m w a s j u d g e d t o p r e s e n t n o f ir e h a z a r d a n d t o p r o v i d e s u b -s t a n t i a l f ir e p r o t e c ti o n . F i r e d a m a g e w a s se v e r e.

A t h e r m a l i n s u l a t i o n s y s t e m c o n s i s t i n g o f t w o l a y e r s o f c e l l u l a r s il ic a ,2 8 9 in . t o t a l th i c k n es s , a n d a p o l y v i n y l a c e t a t e w e a t h e r b a r r i e r m a s t i cg a v e i n t e r n a l p i p e t e m p e r a t u r e s o f 32 0 ~ F a f t e r 3 0 m i n a n d 7 6 0 ~ F a f t e r 6 0r a in . S h r i n k a g e c a u s e d l o n g i t u d i n a l c r a c k s a b o u t 8 8 i n . w i d e a t s e c t i o nj o i n t s i n th e o u t e r l a y e r o f i n s u la t io n . O n e s e c t i o n o f t h e i n s i d e la y e r ,l o c a t e d i n t h e c e n t e r o f t h e fi re ar e a , w a s t h e r m a l l y c r a c k e d b y q u e n c h i n gw a t e r . B e c a u s e o f t h e d o u b l e - l a y e r , s t a g g e r e d - j o i n t c o n s t r u c t i o n , t h e p i p ew a s n o t e x p o s e d t o f l a m e i m p i n g e m e n t . T h i s t h e r m a l i n s u l a t i o n s y s t e mw a s j u d g e d t o p r e s e n t n o f ir e h a z a r d a n d t o p r o v i d e d e s i r a b l e fi r e p r o t e c -t io n . F i r e d a m a g e w a s m o d e r a t e .

A t h e r m a l i n s u la t i o n s y s t e m c o n s i s ti n g o f a s in g le l a y e r o f v e g e t a b l ec o r k , 2 8 9 i n. t h i ck , a n d a p o l y v i n y l a c e t a t e w e a t h e r b a r r i e r g a v e i n t e r n a l


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T h e r m a l I n s u l a t i o n S y s t e m s 279p i p e t e m p e r a t u r e s o f 1 48 ~ F a f t e r 2 2 ~ m i n ( w h e n s h r i n k a g e c r a c k s a tj o i n t s b e c a m e a p p a r e n t ) , 2 3 0 ~ F a f t e r 3 0 m i n , a n d 6 5 0 ~ F a f t e r 6 0 m i n . T h ei n s u l a t io n c o n t i n u e d t o b u r n a f t e r f u e l f l ow w a s s h u t o f f , a n d t h e i n t e r n a lp i p e t e m p e r a t u r e c o n t i n u e d t o ri se . E v e n a f t e r t h e g a s o l i n e f i re w a s e x -t in g u i sh e d , t h e i n s u l a ti o n c o n t i n u e d t o s m o l d e r u n d e r n e a t h t h e w e a t h e rb a r r i er c o a ti n g . T h i s t h e r m a l i n s u l at i o n s y s t e m w a s j u d g e d t o p r e s e n t u n -d e s i r a b l e f ir e h a z a r d a n d t o p r o v i d e d e s i r a b l e f i re p r o t e c t i o n . F i r e d a m a g ew a s s e v e r e .A t h e r m a l i n s u l a t i o n s y s t e m c o n s i s t i n g o f a s i n g le l a y e r o f c e l l u la rp o l y s t y r e n e , 1 i n. t h ic k , a n d a p o l y v i n y l a c e t a t e w e a t h e r b a r r i e r g a v e i n -t e r n a l p i p e t e m p e r a t u r e s o f 1 ,0 7 0 ~ F a f t e r 1 5 m i n a n d 1 , 18 0 ~ F a f t e r 6 0m i n . T h e i n s u l a ti o n s t a r t e d t o m e l t a n d d r i p a f t e r 12 m i n , a n d m e l t e d a n dd r i p p e d f r o m t h e p ip e in , a n d b e y o n d , t h e fi re a r e a a n d b u r n e d . T h ew e a t h e r b a r r i e r r e m a i n e d i n t a c t a n d a c t e d a s a sh i el d , w h i c h p r o v i d e d a na i r s p a c e on th e b o t t o m o f t h e p ip e . T h i s t h e r m a l i n s u l a t i o n s y s t e m w a sj u d g e d t o p r e s e n t u n d e s i r a b l e f ir e h a z a r d a n d t o p ro v.~ de i n s i g n i f ic a n t f i r ep r o t e c ti o n . F i r e d a m a g e w a s s e v er e .

A t h e r m a l i n s u l a t i o n s y s t e m c o n s i s t i n g o f t w o l a y e r s o f g l a s s f i be r ,2 8 9 i n. t o t a l t h i c k n e s s , a n d a p o l y v i n y l c h l o r id e f il m j a c k e t g a v e i n t e r n a lp i p e t e m p e r a t u r e s o f 9 3 0 ~ F a f t e r 3 0 m i n a n d 1 ,3 6 0 ~ F a f t e r 6 0 m i n . T h eo u t e r l a y e r o f i n s u l a t i o n f u s e d a n d w a s l o o s e o n t h e p i p e a f t e r 1 0 m i n , a n dt h e p i p e s a g g e d a f t e r 6 0 m i n . T h e m e l t e d i n s u l a t i o n w a s f u s e d i n t o a g l a s sm a s s i n t h e c e n t e r o f t h e f ir e a r ea . T h i s t h e r m a l i n s u l a ti o n s y s t e m w a sj u d g e d t o p r e s e n t n o f ir e h a z a r d a n d t o p r o v i d e s u b s t a n t i a l f ir e p r o t e c t io n .F i r e d a m a g e w a s s e v e r e .

A t h e r m a l i n s u l a t i o n s y s t e m c o n s i s t i n g o f a l - in . t h i c k i n n e r l a y e r o fc e l l u la r p o l y s t y r e n e , a 1 8 9 t h i c k o u t e r l a y e r o f c e l l u la r gl as s , a n d ap o l y v i n y l a c e t a t e w e a t h e r b a r r i e r m a s t i c g a v e in t e r n a l p i p e t e m p e r a t u r e so f 3 0 0 ~ F a f t e r 1 7 m i n , 1 , 1 2 0 ~ F a f t e r 5 4 m i n , a n d 1 , 1 6 0 ~ F a f t e r 6 0 m i n .T h e p o l y s t y r e n e p y r o l y z e d t o y ie l d v o l at il e s, w h i c h v e n t e d t h r o u g h o p e n -i n g s i n t h e o u t e r l a y e r a n d i g n i t e d a f t e r 9 m i n , a n d l i q u i d w h i c h l e a k e dt h r o u g h t h e o u t e r l a y e r i g n i t e d a f t e r 1 7 m i n . T h e c e l l u l a r g l a s s i n s u l a t i o nw a s f ra g m e n t e d b y t h e r m a l s h o c k b u t w a s r et a in e d b y t h e w e a t h e r b a r -r ie r . A f t e r f u e l f l o w w a s s h u t o f f, t h e c e l l u l a r p o l y s t y r e n e c o n t i n u e d t ob u r n b e n e a t h t h e f r a g m e n t e d o u t e r l a y e r. T h i s t h e r m a l i n s u l a t io n s y s t e mw a s j u d g e d t o p r e s e n t u n d e s i r a b l e fi re h a z a r d a n d t o p r o v i d e s o m e f ir ep r o t e c t i o n . F i r e d a m a g e w a s s e v e r e.A t h e r m a l i n s u l a t i o n s y s t e m c o n s i s t i n g o f a l - i n . t h i c k c e l l u l a r g l a s si n n e r l a y e r , 1 8 9 t h i c k c a l c i u m s i l ic a t e o u t e r l a y e r , a n d p o l y v i n y l a c e -t a t e w e a t h e r b a r r i er g a v e i n t e r n a l p i p e t e m p e r a t u r e s o f 11 7 ~ F a f t e r 3 0 m i na n d 4 0 0 ~ F a f t e r 6 0 ra in . T h e c a l c i u m s i l i c a t e in s u l a t i o n h a d s h r i n k a g ec r a c k s ~ t o ~ in . w i d e a t s e c ti o n j o i n t s b u t m a i n t a i n e d i ts s t r u c t u r a ls t r e n g th . T h e c e ll u la r g la s s i n s u la t i o n w a s s e v e r e l y c r a c k e d f r o m t h e r m a ls h o c k b u t w a s k e p t i n p l a c e b y t h e c a l c i u m s i li ca te . T h i s t h e r m a l i n s u l a ti o ns y s t e m w a s j u d g e d t o p r e s e n t n o f ir e h a z a r d a n d t o p r o v i d e d e s i r a b le f ir ep r o t e c t io n . F i r e d a m a g e w a s s e ve r e.


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2 80 F i r e T e c h n o l o g yA t h e r m a l i n s u l a t i o n s y s t e m c o n s i s t i n g o f f iv e a l u m i n u m r e f l e c ti v es h e e ts , s p a c e d ~ i n. a p a r t w i t h t h e in n e r s h e e t ~ i n. f r o m t h e p i p e s u r f a c e

f o r a t o t a l t h i c k n e s s o f 2 ~ i n. , g a v e i n t e r n a l p i p e t e m p e r a t u r e s o f 1 , 00 0 ~ Fa f t e r 1 2 m i n a n d 1 ,5 0 0 ~ F a f t e r 6 0 m i n . T h e i n s u l a t i o n f a i l e d n e a r t h ec e n t e r o f t h e f ir e a r e a a f t e r 1 8 9 m i n , e x p o s i n g a l e n g t h o f p i p e t o f l a m ei m p i n g e m e n t , a n d t h e p i p e s a g g e d a f t e r 10 r a in . T h i s t h e r m a l i n s u l a t i o ns y s t e m w a s j u d g e d t o p r e s e n t n o f ir e h a z a r d a n d t o p r o v i d e i n s i g n if i ca n tf ir e p r o t e c t i o n . F i r e d a m a g e w a s s e v e r e .

W I D E - R A N G E I N S U L A T I O N S Y S T E M SA t h e r m a l i n s u l a t i o n s y s t e m c o n s i s t i n g o f t w o l a y e r s o f r i g i d c e l lu l a r

p o l y u r e t h a n e ( r a t e d s e lf - e xt in g u is h i ng b y A S T M D 1 6 9 2 - 6 7 T ) , 2 8 9 in .t o t a l t h ic k n e s s , a n d a 1 2 - m fi t h i c k c o a t i n g o f f i r e - r e t a r d a n t p a i n t g a v ei n t e r n a l p i p e t e m p e r a t u r e s o f 4 0 0 ~ F a f t e r 1 5 m i n , 9 0 0 ~ F a f t e r 3 0 m i n ,1 ,0 0 0 ~ F a f t e r 3 2 m i n, a n d 1 ,3 0 0 ~ F a f t e r 6 0 m i n . T h e c e l l u la r p o l y u r e t h a n ew a s d e s t r o y e d i n th e f ir e a r e a b u t d i d n o t p r o p a g a t e f la m e . T h i s t h e r m a li n s u la t io n s y s t e m w a s j u d g e d t o p r e s e n t n o f ir e h a z a r d a n d t o p r o v i d e s u b -s t a n t i a l fi re p r o t e c t i o n . F i r e d a m a g e w a s s e v e r e .

A t h e r m a l i n s u l a t i o n s y s t e m c o n s i s t i n g o f t w o l a y e r s o f r i g id c e l l u l a rp o l y u r e t h a n e ( r a t e d s e lf - e x ti n g u is h i n g b y A S T M D 1 6 9 2 - 6 7 T ) , 2 8 9 in .t o t a l t h i c k n e s s , a n d a 0 .0 1 0 - in . t h i c k s t a i n l e s s s t e e l j a c k e t g a v e i n t e r n a lp i p e t e m p e r a t u r e s o f 9 00 ~ F a f t e r 1 0 m i n , 1 , 00 0 ~ F a f t e r 1 1 m i n , 1 , 50 0 ~ Fa f t e r 3 0 m i n , a n d 1 , 50 0 ~ F a f t e r 6 0 m i n . T h e c e l l u l a r p o l y u r e t h a n e w a sd e s t r o y e d i n t h e f ir e a r e a b u t d i d n o t p r o p a g a t e f la m e . T h i s t h e r m a l in -s u l a t io n s y s t e m w a s j u d g e d t o p r e s e n t n o f ir e h a z a r d a n d t o p r o v i d e i n sig -n i i i c a n t f i re p r o t e c t i o n . F i r e d a m a g e w a s s e v e r e .

A t h e r m a l i n s u l a t i o n s y s t e m c o n s i s t i n g o f a 1 -i n. t h i c k i n n e r l a y e r o fr ig id c el lu l ar p o l y u r e t h a n e ( r a te d s e lf - e x ti n g u is h i n g b y A S T M D 1 6 9 2 - 6 7 T ) ,a l ~ - i n , t h i c k o u t e r l a y e r o f c a l c iu m s il ic a te , a n d a p o l y v i n y l a c e t a t ew e a t h e r b a r r i e r m a s t i c g a v e i n t e r n a l p i p e t e m p e r a t u r e s o f 30 0 ~ F a f t e r3 0 m i n . a n d 1 ,0 0 0 ~ F a f t e r 6 0 m i n . T h e c e ll u la r p o l y u r e t h a n e w a s d e s t r o y e di n t h e f ir e a r e a , b u t t h e c a l c iu m s i l ic a t e r e t a r d e d t h e r a t e o f d e s t r u c t i o ns u b s t a n t i a l ly . T h i s t h e r m a l i n s u l a ti o n s y s t e m w a s j u d g e d t o p r e s e n t nof ir e h a z a r d a n d t o p r o v i d e d e s i r a b le fi re p r o t e c t i o n . F i r e d a m a g e w a ss e v e r e .A t h e r m a l i n s u l a t i o n s y s t e m c o n s i s t i n g o f a 1 -i n. t h i c k s i n g l e l a y e r o fr ig id c e ll u la r p h e n o li c ( r a t e d s e l f- e x ti n g u is h i n g b y A S T M D 1 6 9 2 - 6 7 T ) , a1/3~.-in. t h i c k s h e e t o f a s b e s t o s p a p e r , a n d a p o l y v i n y l a c e t a t e w e a t h e r b a r r i e rm a s t i c g a v e i n t e r n a l p i p e t e m p e r a t u r e s o f 2 1 2 ~ F a f t e r 1 0 m i n , 5 7 0 ~ F a f t e r2 0 r a in , 9 2 0 ~ F a f t e r 3 0 m i n , a n d 1 , 0 0 0 ~ F a f t e r 3 5 m i n . T h e c e l l u l a rp h e n o l ic w a s d e s t r o y e d i n t h e f ir e a r e a , b u t t h e r e w a s n o f l a m e s p r e a d .T h i s t h e r m a l i n s u l a t i o n s y s t e m w a s j u d g e d t o p r e s e n t n o fi re h a z a r d a n dt o p r o v i d e s u b s t a n t i a l f ir e p r o t e c ti o n . F i r e d a m a g e w a s se v e r e .

A t h e r m a l i n s u l a t i o n s y s t e m c o n s i s t in g o f 1 . 25 i n. o f r i g id c e l l u l a r p o l y -u r e t h a n e ( r a t e d s e lf - e x ti n g u is h i ng b y A S T M D 1 6 9 2 - 6 7 T ) a n d a p o l y v i n y lc h l o ri d e j a c k e t g a v e i n t e r n a l p i p e t e m p e r a t u r e s o f 1 ,0 0 0 ~ F a f t e r 1 4 t o


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T h e r m a l I n s u l a t i o n S y s t e m s 2812 0 r a i n , a b o u t 1 ,2 00 ~ F a f t e r 3 0 m i n , a n d a b o u t 1 ,2 5 0 ~ F a f t e r 6 0 m i n .T h i s s y s t e m e m p l o y e d n o s t a in l e s s s te e l w i r e s o r b a n d s , a n d f a i l u r e s a t t h ej o i n t s c a u s e d s e c t i o n s o f in s u l a t i o n t o f a l l o f f e x p o s i n g t h e p i p e t o f l a m ei m p i n g e m e n t . T h e r e w a s n o sp r e a d o f f l a m e b e y o n d t h e fi re a r e a, a n d t h ei n s u l a ti o n w a s d a m a g e d f o r a b o u t 3 f t b e y o n d t h e f ir e a r ea . T h i s t h e r m a li n s u l a ti o n s y s t e m w a s j u d g e d t o p r e s e n t n o f i r e h a z a r d a n d t o p r o v i d es o m e fi re p r o t e c ti o n . F i r e d a m a g e w a s s e v e re .A t h e r m a l i n s u l a t i o n s y s t e m c o n s i s t i n g o f 1 .2 5 i n . o f r i g id c e l l u l a r p o l y -u r e t h a n e ( r a te d b u r n in g b y A S T M D 1 6 9 2 - 6 7 T ) a n d a p o l y v i n y l c h lo r id ej a c k e t g a v e i n t e r n a l p i p e t e m p e r a t u r e s o f 1 ,0 00 ~ F a f t e r 2 3 r a i n , 1 ,1 00 ~ Fa f t e r 3 0 r a in , a n d 1 ,2 00 ~ F a f t e r 6 0 m i n . T h i s s y s t e m e m p l o y e d n o s t a in l e s ss t e e l w i r es o r b a n d s a n d f a i l u re s a t t h e j o i n t s c a u s e d s e c t i o n s o f t h e i n s u la -t i o n t o f a ll o f f e x p o s in g t h e p i p e t o f l a m e i m p i n g e m e n t . T h e r e w a s n os p r e a d o f f l a m e b e y o n d t h e f ir e a r e a a n d t h e i n s u l a t i o n w a s d a m a g e d f o ra b o u t 3 f t b e y o n d t h e fi re a r ea . T h i s t h e r m a l i n s u l a ti o n s y s t e m w a s ju d g e dt o p r e s e n t n o fi r e h a z a r d a n d t o p r o v i d e s o m e f ir e p r o t e c t i o n . F i r e d a m a g ew a s s e v e r e .A t h e r m a l i n s u l a t i o n s y s t e m c o n s i s t i n g o f a 1 - in . t h i c k i n n e r l a y e r o fp e r l i t e a 1 ,4 -in . t h i c k o u t e r l a y e r o f r i g id c e l l u l ar p o l y u r e t h a n e , a n d a p o l y -v i n y l c h l o r id e j a c k e t g a v e i n t e r n a l p i p e t e m p e r a t u r e s o f 30 0 ~ F a f t e r 3 0m i n a n d 6 0 0 ~ F a f t e r 6 0 m i n . T h e o u t e r j a c k e t a n d t h e p o l y u r e t h a n ei n s u l a ti o n w e r e d e s t r o y e d b u t t h e p e r l i te i n s u l at io n , s e c u r e d w i t h s t a in l e s ss t e e l w i r e , r e m a i n e d in p l a ce . Q u e n c h i n g w a t e r s o a k e d t h e p e r l i te i n su l a -t i o n re d u c i n g i ts s tr u c t u r a l s tr e n g t h . T h i s t h e r m a l i n su l a t i o n s y s t e m w a sj u d g e d t o p r e s e n t n o f ir e h a z a r d a n d t o p r o v i d e d e s i r a b l e f i re p r o t e c t i o n .F i r e d a m a g e w a s s e v e r e .

D I S C U S S I O NT h e r e s u lt s o f t h e s e f ir e te s t s e m p h a s i z e t h e i m p o r t a n c e o f p r o p e r d e s i g no f t h e r m a l in s u l a t io n s y s t e m s . W h i l e n o n c o m b u s t i b l e t h e r m a l i n s u la t i o nm a t e r i a l s p r e s e n t e d n o f ir e h a z a r d i n t h e s y s t e m s t e s t e d , t h e d e s ig n o f t h es y s t e m d e t e r m i n e d w h e t h e r a c o m b u s t ib l e i n s u la t io n m a t e r i a l w o u l d p r e -s e n t a fi re h a z a r d . T h e t e n d e n c y o f v e g e t a b l e c o r k to c o n t i n u e b u r n i n gu n d e r a w e a t h e r b a r ri e r, a n d o f c e l lu l a r p o l y s t y r e n e t o d e c o m p o s e i n to

f l a m m a b l e g as e s a n d l i qu id s , p r e s e n t e d h a z a r d s t h a t w e r e n o t e l i m i n a t e db y t h e s y s t e m s in th i s s t u d y . I n c o n t r a s t , r i g i d c e l l u la r p h e n o l i c a n d p o l y -u r e t h a n e , e v e n a p o l y u r e t h a n e r a t e d a s b u r n i n g b y a s m a l l- s c al e te s t , p r e -s e n t e d n o f i r e h a z a r d i n t h e s y s t e m s d e s i g n e d f o r t h e m .F i r e p r o t e c t i o n c o n s i d e r a t io n s a ls o s h o w e d t h e i m p o r t a n c e o f s y s t e md e s ig n . T h e t e n d e n c y o f c e ll u la r g la s s t o f r a g m e n t u n d e r t h e r m a l s h o c km a d e t h i s m a t e r i a l o f n e g li g ib l e f ir e p r o t e c t i o n v a l u e u n t i l i t w a s u s e d i n as y s t e m t h a t k e p t t h e f r a g m e n t s in p la c e.I n s u l a t i o n s y s t e m d e s ig n sh o w e d a n i m p o r t a n t e f f ec t o n f ir e d a m a g e .I n m a n y c a s es , t h e u se o f d o u b l e - l a y e r c o n s t r u c t i o n r e d u c e d d a m a g e f r o mc r~ m p le te r e p l a c e m e n t t o p a r t i a l r e p l a c e m e n t .

P r o p e r d e s ig n o f t h e r m a l i n s u l a t i o n s y s t e m s h a s p a r t i c u l a r s i g ni f ic a n c e


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282 Fire Tec hno log yfor combustible thermal insulation materials, such as cellular plastics.Proper design can eliminate fire hazard, as was shown with rigid cellularphenolic and polyure thane. Poor design can make supposedly noncom-bustible insulation materials of negligible value as fire protection, whileproper design can give cellular plastics substantial fire protection value.The systems concept has brought out an important fact; regardless ofwhether a thermal insulation material is supposedly combustible or non-combustible, the outer layer of insulation is generally damaged severelyenough to require replacement of both outer layer and protec tion material.

F I R E E X P E R I E N C EOn July 18, 1967, a major fire occurred in a chemical processing unitat the Ins titut e Plant of Union Carbide Corporation. The initial fire, be-lieved to result from ignition of toluene released by an equipment failure,produced a fireball extending from ground level to well above the four-level structure. Temperat ures of 950 ~ F to 1,150~ F were reached, andfused glass and melted conduit were evidence of the tremendous heatbuild-up. Prom pt actuation of the water spray system und oub ted ly pre-vented the loss of the entire structure. The fuel tha t fed the fire consistedessentially of approximately 700 gal of toluene.One vessel on the third level had been insulated witha spray-appliedrigid cellular polyure thane (ra ted self-extinguishing by ASTM D1692-67T).A vessel extending from the second to the fourth levels had bee n insulated,

on an experimental basis, wi th a spray-appl ied rigid cellular pol yur ethane(rated burning by ASTM D1692-67T). The insulation on both vesselswas covered with a fire-retardant weather barrier mastic.The cellular polyurethane on the first vessel was complete ly destroyed,and the residue was dislodged by water-hose streams. The cellular poly-urethane on the second vessel, although supposedly less fire resistant, wascompletely destroyed over a portion of the insulated surface, but sub-stantial surface areas survived the fire and water application with abouthalf of the original thickness of insulation undamaged, apparently pro-tecte d from the fire by the we ather barrier and the char formed by destruc-tion of the ou ter layers. The supposedly less fire-resistant mat eri al pro-vided some protection for the second vessel while the supposedly morefire-resistant material provided no protection.

C O N C L U SI O N SNone of the thermal insulation systems tested presented a significantfire hazard with the exception of those systems employing vegetable corkand cellular polystyrene. The hazard presented by ve getable cork is itstendency to continue burning under the weather barrier covering, and thehazard presented by cellular polystyrene is its tendency to produce com-bustible gases and combustible liquids. Cellular polyuret hane, althougha combustible insulation material, presented no significant fire hazard in a

properly designed system because of its tende ncy to form char.


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T h e r m a l I n s u l a t i o n S y s t e m s 2 83S a t i s f a c t o r y f i r e p r o t e c t i o n w a s p r o v i d e d o n l y b y s y s t e m s e m p l o y i n gca l c ium s i li c a te , magnes i a , d i a to m aceo us ea r t h , a sbes to s f ibe r , and a sbes to sf i b e r / p e r l i t e c o m p o s i ti o n s , i n s t a ll e d i n t w o l a y e r s w i t h s t a g g e r e d - j o i n tc o n s t r u c t io n . I n g e n e r a l, n o t h e r m a l i n s u l a t i o n m a t e r i a l i n s i n g l e -l a y e rc o n s t r u c t i o n p r o v i d e d s a t i s f a c to r y f i re p r o te c t i o n . R e f l e c t iv e i n s u l a t io ns y s t e m s e m p l o y i n g s ta i n le s s s te e l o u t e r j a c k e t s p r o v i d e d a d e q u a t e f ir ep r o t e c t i o n .W i t h a l l t h e t h e r m a l i n s u l a t i o n s y s t e m s t e s t e d , f i r e d a m a g e w o u l d r e -q u i r e p a r t i a l o r c o m p l e t e r e p l a c e m e n t . O n l y t h e w e a t h e r b a r r i e r c o v e r in gw o u l d r e q u i r e r e p l a c e m e n t i n t h e c a s e o f s y s t e m s e m p l o y i n g a s b e s to sf i b e r / p e r l i t e c o m p o s i t io n s . T h e w e a t h e r b a r r ie r c o v e ri n g a n d t h e o u t e r

l a y e r o f i n s u l a t i o n m a t e r i a l w o u l d r e q u i r e r e p l a c e m e n t i n t h e c a s e o f s y s -t e m s e m p l o y i n g d o u b l e - l a y e r , s t a g g e r e d - j o i n t i n s t a l l a t i o n s o f c a l c i u ms i l ic a t e , d i a tom aceo us ea r t h , a sb es to s fi be r, and ce l l u l a r g l as s . A l l o th e rs y s t em s w o u l d r e q u i re c o m p l e t e r e p la c e m e n t . F i r e d a m a g e t o m a g n e s i ai n s u l a t io n c o n s i s t e d p r i m a r i l y o f d a m a g e f r o m w a t e r a p p l i c a t io n .

thermal insudcfvfsdfdsfsdlation for pipe

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