Variations in air temperature and carbon dioxide concentration in a heated family fallout shelter

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Variations in air temperature and carbon dioxide concentration in a

heated family fallout shelter

NATIONAL RESEARCH COUNCIL CANADA

DIVISION O F BUILDING RESEARCH

VARIATIONS IN AIR T E M P E R A T U R E AND CARBON DIOXLDE CONCENTRATION IN A HEATED

FAMILY F A L L O U T S H E L T E R

A. D. Kent and N. B. Hutcheon

I n t e r n a l R e p o r t No. 322 of t h e

Division of Building Re s e a r c h

OTTAWA O c t o b e r 1965

P R E F A C E

T h e Division in 1960 undertook s t u d i e s t o r e s o l v e s o m e q u e s t i o n s about t h e heating and ventilation of b a s e m e n t fallout s h e l t e r s . A b a s e m e n t s h e l t e r w a s c o n s t r u c t e d and u s e d i n a n u m b e r of w i n t e r and s u m m e r t r i a l s in 1961 and 1962 which have been r e p o r t e d . T h e work w a s continued i n t h e l a b o r a t o r y with the c o n s t r u c t i o n of a m o c k - u p of the s h e l t e r in which m o r e d e t a i l e d s t u d i e s could be c a r r i e d on independently of t h e w e a t h e r . Investigations of t e m p e r a t u r e g r a d i e n t s , c a r b o n dioxide c o n c e n - t r a t i o n s and ventilation r a t e s a s s o c i a t e d with t h e u s e of s e v e r a l t y p e s and a r r a n g e m e n t s of s m a l l unvented k e r o s e n e s t o v e s f o r

cooking and heating a r e now r e p o r t e d .

M r . Kent i s a R e s e a r c h Officer in t h e Building S e r v i c e s Section, and D r . Hutcheon i s A s s i s t a n t D i r e c t o r of t h e Division.

Ottawa

August 1965

R. F . Legget D i r e c t o r

VARIATIONS IN AIR TEMPERATURE AND

CARBON Dl0XI.DE CONCENTRATION

_IN

A HEATED

FAMILY FALLOUT SHELTER

'JY

A.D. Kent and N . B . Hutcheon

It h a s been d e m o n s t r a t e d f r o m p r e v i o u s s t u d i e s ( 1 ) of a

b a s e m e n t fallout s h e l t e r that w i n t e r t i m e heating of the s h e l t e r can probably be s a t i s f a c t o r i l y a c c o m p l i s h e d by the body h e a t of the f i v e occupants i n a r e a s with m o d e r a t e w i n t e r t e m p e r a t u r e s s u c h a s Halifax and Toronto. W h e r e the n u m b e r of occupants i s f e w e r o r w h e r e m e a n J a n u a r y t e m p e r a t u r e s a r e about 1 0 ° F ,

s u c h a s a t Ottawa, s o m e additional heating i s d e s i r a b l e , and w h e r e m e a n J a n u a r y t e m p e r a t u r e s m a y f a l l below O ° F , s u c h a s a t Saskatoon, heating i s e s s e n t i a l t o p r e v e n t s h e l t e r

t e m p e r a t u r e s f r o m approaching f r e e zing.

It w a s f u r t h e r d e m o n s t r a t e d ( 2 ) t h a t k e r o s e n e -burning

a p p l i a n c e s developing a t o t a l of 4000 ~ t u / h r could be o p e r a t e d

without objectionable o d o u r s i n the s h e l t e r with no s p e c i a l venting a r r a n g e m e n t s and t h a t the c a r b o n dioxide c o n c e n t r a t i o n would be within s a f e l i m i t s provided t h e two u p p e r and two

lower vent openings r e m a i n e d open t o give not l e s s than 8 a i r

changes p e r hour with a c o r r e s p o n d i n g b a s e m e n t ventilation r a t e of not l e s s than 0 . 1 5 a i r changes p e r hour.

F r o m t h e s e s t u d i e s , i t was evident t h a t a s u b s t a n t i a l t e m p e r a t u r e g r a d i e n t f r o m floor t o ceiling could be expected both s u m m e r and winter in s u c h a s h e l t e r , when occupied by five p e r s o n s , even with m o d e r a t e cooking and lighting by k e r o s e n e -burning a p p l i a n c e s . The situation could, of c o u r s e , be f u r t h e r e x a g g e r a t e d by the heating n e c e s s a r y in the w i n t e r t o o v e r c o m e the s u b s t a n t i a l h e a t l o s s e s t o the e x t e r i o r w a l l s and f l o o r of t h e s h e l t e r and t o the low t e m p e r a t u r e b a s e m e n t a i r

flowing in a t the l o w e r ventilation openings. If t h i s cold b a s e m e n t a i r could be heated i m m e d i a t e l y by h e a t e r s a t t h e floor l e v e l ,

s o m e i m p r o v e m e n t of the g r a d i e n t and the consequent c o m f o r t of the occupants might be achieved.

The whole p r o b l e m of how t o b e s t h e a t a fallout s h e l t e r

and what the a c t u a l t e m p e r a t u r e s would be under v a r i o u s combinations and l o c a t i o n s of h e a t e r s w a r r a n t e d f u r t h e r investigation. At the

how t h e s e w e r e a f f e c t e d by t e i n p e r a t u r e g r a d i e n t s p r e s e n t e d a p i - o h l e m . T h e e f f e c t s of u s i n g a h o o d o v e r an a p p l i a n c e t o d i s s i p a t e t h e h e a t and c a r b o n d i o x i d e in t h e s u m m e r w e r e not known, n o r t h e i n f l u e n c e of a d i r e c t - v e n t i n g f l u e pipe f r o m t h e h e a t e r s t o t h e b a s e m e n t a i r by m e a n s of a h e a t e u c h a n g e r . DESCRIPTION O F T E S T S H E L T E R T o s t u d y f u r t h e r t h e v e r t i c a l g r a d i e n t s of t e m p e r a t u r e and c a r b o n d i o x i d e c o n c e n t r a t i o n a n d how t h e y a r e a f f e c t e d b y h e a t e r l o c a t i o n and t h e u s e of a hood o r a h e a t e x c h a n g e r , a m o c k - u p of a b a s e m e n t f a l l o u t s h e l t e r w a s b u i l t i n t h e l a r g e s t r u c t u r e s l a b o r a t o r y of t h e Building R e s e a r c h C e n t r e ( F i g u r e 1 ) . M a d e of wood f r a m e c o n s t r u c t i o n t o f a c i l i t a t e e r e c t i o n , i n s t r u - m e n t a t i o n and d i s m a n t l i n g , t h e m o c k - u p had t h e s a m e g e n e r a l a r r a n g e m e n t a n d d i m e n s i o n s a s t h e f i v e - p e r s o n b a s e m e n t f a l l o u t s h e l t e r r e c o m m e n d e d b y t h e E m e r g e n c y M e a s u r e s O r g a n i z a t i o n ( i n s i d e d i m e n s i o n s ,

9

ft 4 in. by

6

ft 8 i n . w i t h h e i g h t of 78 i n . ) , a p r o t o t y p e of which h a d a l r e a d y b e e n u n d e r s t u d y ( 1 , 2 ) . T o a c h i e v e r o u g h l y t h e s a m e h e a t t r a n s m i s s i o n a s t h e m a s o n r y s h e l t e r , t h e w a l l s a n d c e i l i n g of t h e m o c k - u p w e r e m a d e of 1/2-in. f i b r e b o a r d l i n e d w i t h 1/2-in. p l a s t e r b o a r d , w h i l e t h e f l o o r w a s m a d e u p of 3/4-in. plywood w i t h 1/2-in. p l a s t e r b o a r d c o v e r . An e n v e l o p e of 5 - m i l polythene w a s s t a p l e d t o t h e i n t e r i o r p r i o r t o t h e p l a s t e r b o a r d i n t e r i o r f i n i s h b e i n g a p p l i e d , a n d t h i s w a s c a r e f u l l y t e r m i n a t e d a t t h e f r a m e s of d o o r s , windows a n d vent o p e n i n g s t o f o r m a t i g h t s e a l . F o u r u p p e r a n d f o u r l o w e r vent o p e n i n g s , e a c h 1 7 . 31 s q i n . in a r e a , f o r m e d by t h e d o u b l e h o l e s of f o u r c o n c r e t e b l o c k s w e r e p r o v i d e d i n one l o n g w a l l of t h e s h e l t e r , t h e o p e n i n g s having t h e s a m e p o s i t i o n s a n d d i m e n s i o n s a s i n t h e m a s o n r y s h e l t e r . A plywood d o o r , l i n e d w i t h p l a s t e r - b o a r d a n d c o m p l e t e l y w e a t h e r s t r i p p e d , w a s f i t t e d in one e n d w a l l . No a t t e m p t w a s m a d e t o s i m u l a t e t h e bunk a r r a n g e m e n t s o r t h e e n t r a n c e w a y . T w o o b s e r v a t i o n w i n d o w s , e a c h c o n s i s t i n g of t w o s e a l e d d o u b l e - g l a z e d p a n e l s f a c e t o f a c e w e r e i n s t a l l e d b e t w e e n t h e two s e t s of u p p e r a n d l o w e r v e n t s , t h e f o u r g l a s s p a n e s w i t h t h e i r e n c l o s e d a i r s p a c e s giving r o u g h l y t h e s a m e h e a t t r a n s m i s s i o n f a c t o r a s t h e r e m a i n d e r of t h e w a l l . A s h e e t m e t a l h o o d , 20 i n . by 1 8 i n . w i t h a 12 i n . d e p t h a t t h e w a l l a n d of t h e s a m e d e s i g n a s i n t h e b a s e m e n t s h e l t e r , w a s i n s t a l l e d a t one of t h e u p p e r vent o p e n i n g s ( F i g u r e 2 ) . E l e c t r i c p o w e r f o r l i g h t s a n d o u t l e t s w a s p r o v i d e d in t h e s h e l t e r t h r o u g h a s p e c i a l w a t t - h o u r m e t e r m o u n t e d o u t s i d e t h e s h e l t e r .

INSTRUMENTATION T o m e a s u r e t h e a i r t e m p e r a t u r e g r a d i e n t in t h e s h e l t e r , a s e r i e s of t h e r m o c o u p l e s w a s p o s i t i o n e d in t h e c e n t r e of t h e s h e l t e r a t t h e e l e v a t i o n s 6, 1 8 , 30, 48, 60 and 72 i n . above t h e f l o o r ( F i g u r e 3 ) . T h e t h e r m o c o u p l e s w e r e c o p p e r - c o n s t a n t a n and w e r e c o n n e c t e d t o a r e c o r d i n g p o t e n t i o m e t e r ( F i g u r e 4 ) . S i m i l a r t h e r m o c o u p l e s l o c a t e d a t t h e c e n t r e of t h e c r o s s - s e c t i o n of e a c h of t h e e i g h t vent openings of t h e s h e l t e r and one t h e r m o - couple a d j a c e n t t o t h e i n s i d e w a l l s u r f a c e a t a height m i d w a y

between t h e u p p e r and l o w e r vent c e n t r e l i n e s w e r e a l s o 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 along w i t h one t h e r m o c o u p l e t o r e g i s t e r t h e a m b i e n t a i r t e m p e r a t u r e of t h e l a b o r a t o r y a t t h e m i d - h e i g h t of t h e s h e l t e r w a l l . A h y g r o t h e r m o g r a p h w a s p o s i t i o n e d a t t h i s s a m e l o c a t i o n in t h e l a b o r a t o r y t o r e c o r d a i r t e m p e r a t u r e a n d r e l a t i v e h u m i d i t y . C a r b o n dioxide c o n c e n t r a t i o n w a s r e c o r d e d f o r a i r s a m p l e s t a k e n n e a r t h e c e n t r e p o s t i n t h e s h e l t e r , a t e l e v a t i o n s

12 i n . f r o m t h e f l o o r , 12 i n . below t h e c e i l i n g and a t m i d -height

( 3 9 i n . e l e v a t i o n ) . The s a m p l e s w e r e t r a n s p o r t e d t h r o u g h p l a s t i c tubing l e a d i n g f r o m t h e s a m p l i n g p o i n t s t h r o u g h o n e vent opening t o a n i n f r a r e d type g a s a n a l y s e r by way of a m u l t i p l e s e l e c t o r valve and d i a p h r a g m pump ( F i g u r e 4 ) . T h e s e l e c t o r valve w a s o p e r a t e d by t h e 16-point 1 - m i n p r i n t r e c o r d i n g m i l l i v o l t m e t e r of t h e a n a l y s e r i n s u c h a w a y t h a t 3 - m i n s a m p l e s w e r e obtained a t e a c h of t h e t h r e e s a m p l i n g p o i n t s , followed by a 4 - m i n c a l i b r a t i o n c h e c k s a m p l e f r o m a c y l i n d e r of d r y n i t r o g e n ( 0 p e r c e n t GO2) a n d a 3 - m i n c h e c k s a m p l e of c a l i b r a t i o n g a s ( 1 p e r c e n t GO2). HEATING EQUIPMENT In t h e s e a r c h f o r a type of h e a t e r f o r f a l l o u t s h e l t e r a p p l i c a t i o n w h i c h would be i n e x p e n s i v e , r e a s o n a b l y s a f e and c l e a n t o o p e r a t e and which could be u s e d a l s o a s a c o o k e r , a t y p e of

s m a l l c i r c u l a r c o o k e r with two f l a t w i c k s h a d shown c o n s i d e r a b l e p r o m i s e d u r i n g p r e v i o u s s h e l t e r t e s t s ( F i g u r e

5 ) .

A n o t h e r type of h e a t e r ( F i g u r e 6) u s i n g a s l e e v e b u r n e r with c i r c u l a r w i c k , a n d equipped with a n i n t e g r a l b a r o m e t r i c t a n k , r a d i a n t r e f l e c t o r a n d a cooking g r i d , had b e e n found t o h a v e about t h r e e t i m e s t h e h e a t i n g c a p a c i t y of t h e s m a l l e r f l a t - w i c k type c o o k e r and had o p e r a t e d with l e s s odour ( e x c e p t on e x t i n g u i s h m e n t ) . It a l s o had a m u c h s l o w e r r e s p o n s e on s t a r t i n g a n d stopping and a c o s t of about five t i m e s t h e o t h e r t y p e .

T h r e e h e a t e r s of the f l a t -wick c o o k e r type and one h e a t e r of the s l e e v e b u r n e r type w e r e u s e d in t h e s e t e s t s . A s i m p l e heat e x c h a n g e r c o n s t r u c t e d f r o m 6-in. black flue pipe

( F i g u r e 7 ) w a s a l s o used in tlie t e s t s in additi.on t o the hood

p r e v i o u s l y m e n t i o n e d , t o d e t e r m i n e the effect of d i r e c t venting on the r e d u c t i o n of c a r b o n dioxide c o n c e n t r a t i o n within the s h e l t e r , and t o a s s e s s the c o m p a r a t i v e s a v i n g s in h e a t between the s i m p l e hood and the s p e c i a l heat e x c h a n g e r . T h e heat

e x c h a n g e r a c t e d a s a flue pipe in c a r r y i n g the combustion g a s e s f r o m the h e a t e r ( o r h e a t e r s ) placed on the f l o o r of the s h e l t e r t o the u p p e r vent opening equipped wlth tne hood.

TEST RESULTS

T h e f i r s t s e r i e s of t e s t s ( T e s t s 1 t o 4 ) w a s c a r r i e d out u s i n g t h r e e of the "Hot B l a s t " f l a t - w i c k type cook s t o v e s , placed on the f l o o r , with and without the u s e of the heat e x c h a n g e r f o r

two of the t h r e e u n i t s . T h e second s e r i e s ( T e s t s 5 t o

9 )

u t i l i z e d

two of the wick type c o o k e r s in v a r i o u s p o s i t i o n s , on the f l o o r , on the t a b l e , u n d e r the hood, e t c . , while the t h i r d s e r i e s ( T e s t s 10 t o 13) u s e d only one c o o k e r of t h i s t y p e . In t h e f o u r t h s e r i e s of t e s t s ( T e s t s 14 t o 1 6 ) , one1'Hot B l a s t " c o o k e r and t h e "Podette" h e a t e r with s l e e v e - t y p e b u r n e r w e r e u s e d in v a r i o u s p o s i t i o n s . All final r e a d i n g s w e r e taken only a f t e r a r e a s o n a b l y s t e a d y s t a t e of t e m p e r a t u r e and c a r b o n dioxide c o n c e n t r a t i o n had been a c h i e v e d .

T h e r e s u l t s of the t e s t s a r e plotted in F i g u r e s 8 ,

9

and

10. F i g u r e 8 g i v e s the t e m p e r a t u r e g r a d i e n t and c a r b o n dioxide g r a d i e n t c u r v e s e x p e r i e n c e d in the s h e l t e r with v a r i o u s c o m b i - n a t i o n s of one, two and t h r e e cook s t o v e s u s e d f o r heating and s e t on the f l o o r . C u r v e s 1 t o 4 i n c l u s i v e a r e b a s e d on t h r e e

u n i t s in o p e r a t i o n , c u r v e s 5 and

6

with two u n i t s , and c u r v e s

10 and 13 with only one unit in o p e r a t i o n .

F i g u r e 9 _{g i v e s the t e m p e r a t u r e g r a d i e n t and c a r b o n}

dioxide g r a d i e n t c u r v e s f o r two cook s t o v e s placed in v a r i o u s p o s i t i o n s , on the f l o o r with and without h e a t e x c h a n g e r , on a

t a b l e u n d e r the hood and with the hood r e m o v e d . C u r v e s 5

and

6

a r e r e p e a t e d f r o m F i g u r e 8 f o r c o m p a r i s o n .

F i g u r e 10 r e p e a t s the c u r v e s 10 and 1 3 f r o m F i g u r e 8 showing the p e r f o r m a n c e of a single "Hot B l a s t " stove on the

of a single stove under the hood while elevated on a table

( c u r v e No. 1 1 ) . C u r v e s 14, 1 5 and 16 give the p e r f o r m a n c e

of the "Podette" h e a t e r in two positions

-

on t h e f l o o r , and on

the table under the vent hood.

During the a n a l y s i s of the r e s u l t s of the p e r f o r m a n c e t e s t s of o n e , two and t h r e e "Hot B l a s t " s t o v e s located on the f l o o r , t h e r e was s o m e doubt a s t o the r e l i a b i l i t y of the r e s u l t s . F o r e x a m p l e , the unusual bends in the t e m p e r a t u r e c u r v e s

between the 20-in. and 30-in. elevation w e r e difficult t o explain. Additional t e s t s w e r e t h e r e f o r e conducted r e p e a t i n g t h e s e

conditions, the r e s u l t s of which a r e shown in F i g u r e 11, c u r v e s B3, B 5 and B10 c o r r e s p o n d i n g r e s p e c t i v e l y t o c u r v e s 3, 5 and

10 in F i g u r e 8. An e x t r a t e s t w a s a l s o conducted with the t h r e e

s t o v e s on the floor grouped together between the two l o w e r

v e n t s , the r e s u l t s of which a r e shown in c u r v e BX. It is

i n t e r e s t i n g t o c o m p a r e t h i s c u r v e with c u r v e B3 of F i g u r e 11

o r c u r v e 3 of F i g u r e 8 w h e r e the t h r e e s t o v e s w e r e located on

the f l o o r e a c h a p p r o x i m a t e l y c e n t r e d in one t h i r d of the floor a r e a .

It w a s evident a l s o f r o m the r e s u l t s of the f i r s t t e s t s that t h e ventilation r a t e of the m o c k - u p s h e l t e r would have t o be e s t a b l i s h e d f o r e a c h condition and in o r d e r t o obtain t h i s , the coefficient of d i s c h a r g e through the block openings of the upper and lower vents would have t o be d e t e r m i n e d . A t e s t was t h e r e f o r e conducted under i s o t h e r m a l conditions, using a n a c c u r a t e flow m e t e r and m i c r o m a n o m e t e r r e s u l t i n g in the coefficient c u r v e of F i g u r e 12.

DISCUSSION O F RESULTS

It was p o s s i b l e a t the o u t s e t t o p r e d i c t f r o m a g e n e r a l knowledge of heating, ventilation and a i r m o v e m e n t in r o o m s , t h a t the u s e of s m a l l s t o v e s e m i t t i n g t h e i r heat m a i n l y t h r o u g h high t e m p e r a t u r e g a s s t r e a m s r i s i n g f r o m t h e m would l e a d t o m a r k e d t e m p e r a t u r e g r a d i e n t s o v e r the height of the r o o m . It could a l s o be p r e d i c t e d t h a t s i n c e t h e p r i m a r y a i r flow r a t e involved in t h e s e s t r e a m s would be s m a l l , c o m p a r e d with the

g e n e r a l ventilation r a t e induced in the s h e l t e r through the openings provided, t h a t the cool e n t e r i n g a i r a t the l o w e r openings would e x e r t a m a r k e d influence on t e m p e r a t u r e s n e a r the f l o o r . T h e v e r t i c a l t e m p e r a t u r e d i s t r i b u t i o n i s a l s o affected by the amount of s e c o n d a r y a i r e n t r a i n e d by the r i s i n g hot g a s plume f r o m a

h e a t e r . C o r r e s p o n d i n g l y , t h e r e i s a downward flow of a i r a t t h e w a l l s w h e r e it i s cooled in c o n t a c t with t h e m and b e c o m e s h e a v i e r

.

T h e g e n e r a l p a t t e r n of a i r m o v e m e n t within t h e t e s t s p a c e c a n t h u s be s e e n t o be t h e r e s u l t of a n u p w a r d flow of hot g a s e n t r a i n i n g a i r a s i t flows u p w a r d , and a downward flow a t t h e w a l l s , t h e s e being c o m b i n e d with a g e n e r a l u p w a r d flow of a i r r e s u l t i n g f r o m t h e r e l a t i v e l y l a r g e v e n t i l a t i o n r a t e , with c o o l a i r e n t e r i n g a t t h e l o w e r v e n t s and w a r m a i r l e a v i n g a t t h e u p p e r v e n t s . T h e t e m p e r a t u r e s and flow r a t e s a r e m u t u a l l y i n t e r d e p e n d e n t , a s a i r c i r c u l a t i o n i s p r o d u c e d by d i f f e r e n c e s in t e m p e r a t u r e , while t e m p e r a t u r e s in t h e a i r a r e s u b s t a n t i a l l y a f f e c t e d by a i r c i r c u l a t i o n . It i s not p o s s i b l e to. p r e d i c t t h e n e t e f f e c t s of t h i s c o m p l e x p a t t e r n of a i r flow e x c e p t i n a v e r y g e n e r a l way a n d s o i t w a s n e c e s s a r y t o e x p l o r e t h e m by a c t u a l m e a s u r e m e n t s s u c h a s a r e now r e p o r t e d . It m u s t be r e c o g n i z e d t h a t t h e c o n d i t i o n s in a r e a l s h e l t e r c a n d i f f e r in s i g n i f i c a n t w a y s f r o m t h o s e r e p r e s e n t e d i n t h e t e s t s h e l t e r s o t h e r e s u l t s obtained a r e a t b e s t only a r o u g h a p p r o x i m a t i o n . T h e y d o , h o w e v e r , p r o v i d e a b a s i s f o r i m p r o v e d judgement in d e a l i n g w i t h r e a l s i t u a t i o n s . T h e m o c k - u p s h e l t e r e n c l o s u r e i t self p r o v i d e d - t h e fir s t s i m p l i f i c a t i o n of t h e r e a l c a s e . It w a s s e t i n a l a r g e r o o m a t roughly c o n s t a n t t e m p e r a t u r e w h e r e a s a r e a l s h e l t e r w i l l be e x p o s e d t o d i f f e r e n t t e m p e r a t u r e s on d i f f e r e n t s i d e s . T h e w a l l , f l o o r and s u r f a c e t e m p e r a t u r e s a n d , t h e r e f o r e , t h e downward a i r flow p a t t e r n w i l l be d i f f e r e n t in a r e a l s h e l t e r . T h i s downward flow w i l l be f u r t h e r modified by bunks a n d o t h e r f u r n i s h i n g s , which w e r e o m i t t e d in t h e s e t e s t s . Another a p p r o x i m a t i o n i s i n t r o d u c e d in t h e t e s t t e m p e r a t u r e s . T h e s h e l t e r w a s in t h i s c a s e e x p o s e d on a l l f o u r s i d e s and on t o p t o l a b o r a t o r y a i r a t about 7 3 " F , a n d t o a r a t h e r u n c e r t a i n s i t u a t i o n a t t h e f l o o r p r o d u c e d by i t s r e l a t i o n t o t h e l a b o r a t o r y f l o o r w h i c h w a s a s l a b on g r o u n d n e a r t h e c e n t r e of a l a r g e building and s o w a s a f e w d e g r e e s c o o l e r t h a n t h e l a b o r a t o r y a i r . S o m e v a r i a t i o n s a l s o o c c u r r e d a t t i m e s in t h e l a b o r a t o r y a i r t e m p e r a t u r e and i n i t s v a r i a t i o n o v e r t h e height of t h e s h e l t e r . T h e s e v a r i a t i o n s w e r e d i s r e g a r d e d . It w a s f u r t h e r a s s u m e d t h a t t h e d i f f e r e n c e s i n a i r t e m p e r a t u r e

t l l r o t ~ g h o ~ ~ t the sllelt.ci- dtli-i11g I h c t e s t s would he r e l a t i v e l y unaffected by the l e v e l of t e m p e r a t u r e . T h a t i s , it w a s a s s u t ~ ~ e d , in p l a i ~ n i n g the t e s t s , t h a t a. given hea.ter a r r a n g e

-

~ n e ~ ~ t would p r o v i d e [lie s a m e t e m p e r a t u r e r i s e above a m b i e n t

a i r a t 7 3 ° F a s would have o c c u r r e d had t h e a m b i e n t a i r been a t sorrxe m o r e r e p r e s e n t a t i v e t e m p e r a t u r e of, s a y , 3 0 ° F .

T h e m o c k - u p s h e l t e r w a s u n o c c u p i e d , but o c c u p a n c y w a s r o u g h l y s i m u l a t e d by t h e u s e of an a d d i t i o n a l s t o v e in a n u m b e r of the t e s t s . A "Hot B l a s t f ' s t o v e b u r n i n g a t the r a t e of

2000 ~ t u / h r p r o v i d e s about t h e s a m e h e a t , and r o u g h l y t h e s a m e c a r b o n dioxide a s five o c c u p a n t s . O c c u p a n t s , h o w e v e r , e m i t t h e i r h e a t p a r t l y in t h e f o r m of m o i s t u r e in t h e b r e a t h and f r o m p e r s p i r a t i o n , and p a r t l y by s e n s i b l e h e a t l o s s f r o m t h e body which o p e r a t e s a s a low t e m p e r a t u r e s t o v e a t a t e m p e r a t u r e of 9 8 ° F o r l o w e r s o t h e a i r s t r a t i f i c a t i o n induced by t h e m would be m u c h l o w e r t h a n t h a t of t h e s t o v e u s e d . F u r t h e r , t h e l a t e n t h e a t r e p r e s e n t e d in t h e m o i s t u r e given off by o c c u p a n t s d o e s not c o n t r i b u t e t o t h e t h e r m a l s i t u a t i o n in t h e r e a l s h e l t e r e x c e p t when it i s condensed on cold s h e l t e r s u r f a c e s , r e l e a s i n g i t s l a t e n t h e a t of e v a p o r a t i o n . T h i s d o e s o c c u r in p a r t in s o m e r e a l s i t u a t i o n s . F i n a l l y , t h e p r o p o r t i o n of t o t a l h e a t e m i t t e d by r a d i a t i o n f r o m o c c u p a n t s and t h e w a y it i s d i s t r i b u t e d t o t h e s h e l t e r s p a c e i s only v e r y r o u g h l y r e p r e s e n t e d by t h e s t o v e s i m u l a t i o n . ( a ) T e m p e r a t u r e V a r i a t i o n T h e r e s u l t s of F i g u r e 8 m a y now be r e - e x a m i n e d i n t h e l i g h t of t h e f o r e g o i n g d i s c u s s i o n . C u r v e 10 f o r one s t o v e on t h e f l o o r o p e r a t i n g a t a f u e l r a t e of 4 3 g m / h r m a y be r e g a r d e d a s t h e r o u g h a p p r o x i m a t i o n t o five o c c u p a n t s . C u r v e s 5 a n d 3 p r o v i d e t h e r e s u l t s f o r t w o and t h r e e s t o v e s o p e r a t i n g a t t o t a l f u e l input r a t e s of 109 and 1 2 3 g r n / h r r e s p e c t i v e l y . T h e m a r k e d t e m p e r a t u r e v a r i a t i o n in a l l t h r e e c a s e s m a y be o b s e r v e d . It m u s t be noted t h a t t h e s e r e s u l t s w e r e obtained by a r b i t r a r i l y s e l e c t e d s t o v e l o c a t i o n s , with m e a s u r e m e n t s m a d e a t one l o c a t i o n in plan, in an u n f u r n i s h e d s p a c e . T h e f u e l input r a t e s of t h e t h r e e s t o v e s , although c o n s t a n t f o r a n y one t e s t , v a r i e d f r o m one t e s t t o a n o t h e r s u c h t h a t f u e l r a t e s f o r two and t h r e e s t o v e s w e r e not a l w a y s e x a c t l y two and t h r e e t i m e s the r a t e of a s i n g l e s t o v e . N e v e r t h e l e s s , t h e t e m p e r a t u r e c u r v e s d o p r o v i d e s o m e i n d i c a t i o n of t h e t e m p e r a t u r e v a r i a t i o n s t o be e x p e c t e d i n a r e a l s i t u a t i o n .

T h e i n c r e a s e i n m e a s u r e d t e m p e r a t u r e a t t h e c e i l i n g f o r t h e s e t e s t s w a s 21, 31 and 36 F d e g above t h e i n c o m i n g a i r a t 7 2 ° F a c c o r d i n g t o c u r v e s 10, 5 and 3 r e s p e c t i v e l y . T h e c o r r e s p o n d i n g m e a n i n s i d e t e m p e r a t u r e d i f f e r e n c e i n t e g r a t e d o v e r t h e height between v e n t s w a s 1 3 , 23 a n d 30

_F

d e g r e s p e c t i v e l y . F o r t h e r e r u n t r i a l s u s i n g o n e , two and t h r e e s t o v e s , t h e f u e l r a t e s w e r e a l l s o m e w h a t l e s s t h a n t h e p r e v i o u s r u n s , n a m e l y 33, 76 a n d 109 g m / h r r e s p e c t i v e l y , w h i c h would a c c o u n t f o r d i f f e r e n c e s b e t w e e n c u r v e s B10, B 5 and B3 of F i g u r e 11 a n d t h o s e of t h e o r i g i n a l r u n , a l t h o u g h t h e s h a p e s of t h e c o r r e s p o n d i n g c ~ i k v e s a r e s i m i l a r . C e i l i n g t e m p e r a t u r e s w e r e 12, 26 a n d 31 F d e g above t h e i n c o m i n g a i r a t a b o u t 7 5 ° F . T h e m e a n i n s i d e t e m p e r a t u r e d i f f e r e n c e b e t w e e n v e n t s w a s r e s p e c t i v e l y 8 , 1 9 a n d 24 F d e g . ( b ) C a r b o n Dioxide V a r i a t i o n T h e v a r i a t i o n s i n t h e c o n c e n t r a t i o n of c a r b o n d i o x i d e e m a n a t i n g f r o m o n e , t w o and t h r e e s t o v e s l o c a t e d on t h e f l o o r c a n be followed f r o m t h e c u r v e s of F i g u r e s 8 and 11 i n m u c h t h e s a m e way a s t h e t e m p e r a t u r e s . T h e e f f e c t of t h e i n c o m i n g f r e s h a i r t h r o u g h t h e l o w e r v e n t s is a p p a r e n t a n d i s q u i t e s i m i l a r t o t h e e f f e c t on t h e t e m p e r a t u r e g r a d i e n t s . T h e i n c r e a s e s i n c a r b o n dioxide a t t h e l e v e l of t h e o u t l e t vent w e r e 0. 1 1 , 0 . 1 8 a n d 0 . 2 0 p e r c e n t f o r o n e , t w o and t h r e e s t o v e s a c c o r d i n g t o c u r v e s 1 0 ,

5

a n d 3 i n F i g u r e 8 and w e r e 0 . 1 1 , 0 . 1 6 a n d 0 . 1 8 a c c o r d i n g t o t h e r e r u n t e s t c u r v e s B 1 0 , B 5 and B 3 i n F i g u r e 11. ( c ) V e n t i l a t i o n R a t e T h e t h e o r e t i c a l p r e s s u r e d i f f e r e n c e a c r o s s t h e t o p and b o t t o m v e n t o p e n i n g s due t o c h i m n e y e f f e c t of t h e a i r c o l u m n s i n s i d e and o u t s i d e t h e s h e l t e r c a n be e x p r e s s e d a s follows: w h e r e p = the t h e o r e t i c a l p r e s s u r e d i f f e r e n c e ( i n . w a t e r ) h = t h e d i s t a n c e b e t ween t o p a n d b o t t o m vent o p e n i n g s , o r t h e e f f e c t i v e c h i m n e y h e i g h t ( f t )

t = the m e a n o u t s i d e t e m p . between t o p and b o t t o m v e n t s ( O F )

0

t . = t h e m e a n i n s i d e t e m p . b e t w e e n t o p a n d b o t t o m v e n t s ( O F ) .

If Q1 i s the quantity of a i r in c f m p a s s i n g t h r o u g h one of the u p p e r v e n t s , then - whe r e C1 = coefficient of d i s c h a r g e f o r t h e u p p e r vent A a r e a of vent opening ( s q f t ) p1 = p r e s s u r e d i f f e r e n c e a t u p p e r vent ( i n . w a t e r )

1 = density of a i r at upper vent (lb p e r cu f t ) .

T h e a r e a of e a c h of t h e f o u r u p p e r and f o u r l o w e r vent openings w a s m e a s u r e d t o be 0. 12 s q f t . T h e c o e f f i c i e n t C w a s d e r i v e d f r o m t h e u p p e r c u r v e of F i g u r e 12. T h u s , a value of Q1 w a s obtained in t e r m s of p l . In a s i m i l a r m a n n e r , t h e e x p r e s s i o n Q 2 f o r t h e l o w e r v e n t s w a s obtained in t e r m s of p 2 . T h e n , s i n c e t h e w e i g h t s of a i r p a s s i n g t h r o u g h t h e u p p e r and l o w e r v e n t s a r e e q u a l and t h e d e n s i t i e s a r e known f r o m t h e t e m p e r a t u r e m e a s u r e m e n t s , p l c a n be e x p r e s s e d in t e r m s of p 2 . Knowing t h e s u m of p i and p 2 f r o m t h e f o r m u l a p = p l p2 the v a l u e s of p l a n d p2 c a n be d e t e r m i n e d f o r e a c h t e s t , along w i t h t h e v a l u e s of Q1 and Q2. Multiplying Q 1 and Q 2 e a c h by f o u r , t h e ventilation r a t e of t h e r o o m c a n be d e t e r m i n e d .

T h u s t h e ventilation r a t e s , b a s e d on 7 0 ° F a i r , w e r e 33, 4 5 and 54 c f m f o r t e s t s 10, 5 and 3 r e s p e c t i v e l y , and w e r e 31, 47

and 53 c f m f o r t e s t s B10, B 5 and B 3 . In a s i m i l a r m a n n e r , t h e ventilation r a t e s c a n be c a l c u l a t e d f r o m t h e c a r b o n dioxide c o n c e n t r a t i o n s f r o m t h e f o r m u l a : 100 B _{- -} 1 . 67B Q = w h e r e Q = ventilation r a t e ( c f m ) B = CO p r o d u c t i o n ( c f h ) 2 C = C 0 2 c o n c e n t r a t i o n a t o u t l e t

(%)

2 C = C O c o n c e n t r a t i o n a t inlet (%) 1 2

T h i s r e l a t i o n s h i p i s b a s e d a 1 a C 0 2 p r o d u c t i o n r a t e e q u a l t o 0 . 059 c u ft f o r e v e r y g r a m of f u e l b u r n e d . T h e v e n t i l a t i o n r a t e s b a s e d on 7 0 ° F a i r , c a l c u l a t e d f r o m t h e c a r b o n dioxide c o n c e n t r a t i o n s t h e n b e c o m e , f o r t h e c u r v e s 10, 5 and 3 of F i g u r e 8 , t h e following v a l u e s : 35, 56 and 61 c f m ; a n d f o r the c u r v e s B 1 0 , B 5 and I33 of F i g u r e 1 1 , t h e v a l u e s 31, 47 and 59 c f m .

F i g u r e 1 3 s h o w s t h e v e n t i l a t i o n r a t e , t h e t e m p e r a t u r e a t t h e u p p e r v e n t s , and t h e C 0 2 c o n c e n t r a t i o n a t t h e u p p e r v e n t s , a l l plotted a g a i n s t t o t a l h e a t input, including t h e s i m u l a t e d h e a t input f r o m people a s w e l l a s f r o m a p p l i a n c e s . It is e v i d e n t t h a t t h e a i r t e m p e r a t u r e and t h e C 0 2 c o n c e n t r a t i o n a t t h e u p p e r vent i n c r e a s e with h e a t input, but a s t h e v e n t i l a t i o n r a t e a l s o i n c r e a s e s , t h e t e m p e r a t u r e and C 0 2 c u r v e s f l a t t e n o u t , i n d i c a t i n g a t e n d e n c y f o r self - r e g u l a t i o n . T h e s e f a c t o r s a r e l a r g e l y , but not u n i q u e l y , r e l a t e d t o t o t a l h e a t input s i n c e t h e y depend on t h e v e r t i c a l

t e m p e r a t u r e g r a d i e n t p r o d u c e d a s w e l l , which m a y v a r y with t h e t y p e and a r r a n g e m e n t of h e a t e r s u s e d . I n p u t s of 1500, 3000 and 4500 B t u w e r e a c h i e v e d with 1 , 2 and 3 s t o v e s r e s p e c t i v e l y , a p a r t f r o m t h e c a s e of t h e " P o d e t t e " h e a t e r , a l s o shown, which p r o d u c e d about 6000 ~ t u / h r . It i s not c l e a r j u s t why t h e l a t t e r should have shown a p r o p o r t i o n a t e l y l o w e r v e n t i l a t i o n r a t e and h i g h e r c a r b o n dioxide c o n c e n t r a t i o n i n r e l a t i o n t o t e m p e r a t u r e a t t h e u p p e r vent.

( d ) Influence of H e a t E x c h a n g e r and Appliance L o c a t i o n

T h e p e r f o r m a n c e of t h e h e a t e x c h a n g e r i s r e f l e c t e d i n c u r v e s 1 3 and 6 of F i g u r e 8 . T h e c a r b o r - dioxide i n c r e a s e w a s v e r y s m a l l , a s would be e x p e c t e d , a s t h e h e a t e x c h a n g e r

d e l i v e r e d the g a s e s of c o m b u s t i o n i n t o t h e hood a t one of t h e u p p e r v e n t s . A c o m p a r i s o n of c u r v e 6 with c u r v e 10 s h o w s

s o m e i m p r o v e m e n t in t e m p e r a t u r e g r a d i e n t but a l s o i n d i c a t e s t h a t t w o s t o v e s in t h e h e a t e x c h a n g e r a r e r e q u i r e d t o p r o d u c e m u c h t h e s a m e r e s u l t a s one open s t o v e . T h u s , r o u g h l y half t h e h e a t w a s c a r r i e d out t h r o u g h the vent when t h e h e a t e x c h a n g e r w a s u s e d . Any i n c r e a s e in t h e h e a t e x c h a n g e r s u r f a c e d i d not

s e e m j u s t i f i e d .

C u r v e s 5 and 6 f r o m F i g u r e 8 a r e r e p e a t e d i n F i g u r e 9

t o p r o v i d e a r e a d y c o m p a r i s o n with t h e r e s u l t s obtained by o t h e r a r r a n g e m e n t s with s t o v e s e l e v a t e d t o t h e t a b l e - t o p l e v e l

a s shown by c u r v e s 7, 8 and

9.

It i s obvious t h a t r a i s i n g t h e

dioxide n e a r t h e c e i l i n g l e a v i n g t h e b o t t o m half of t h e r o o m f a i r l y c l e a r of c o n t a m i n a t i o n w h i l e , a t t h e s a m e t i m e , r e d u c i n g the t e m p e r a t u r e a t l o w e r l e v e l s . S o m e i m p r o v e m e n t in

t e m p e r a t u r e w a s a c h i e v e d by e l i m i n a t i n g t h e hood and placing t h e h e a t e r s one u n d e r e a c h u p p e r vent a t t a b l e - t o p l e v e l . S i m i l a r p e r f o r m a n c e r e s u l t e d f r o m e x p e r i m e n t s i n placing t h e " P o d e t t e " h e a t e r in v a r i o u s p o s i t i o n s , a s shown by c u r v e s 14, 1 5 and 16 in F i g u r e 10. It is w o r t h noting t h a t t h e c a r b o n d i o x i d e c o n c e n t r a t i o n a t t h e b r e a t h i n g l e v e l of a s e a t e d o c c u p a n t w a s r e d u c e d g r e a t l y without a p p r e c i a b l e r e d u c t i o n in t e m p e r a t u r e by moving t h e h e a t e r along t h e f l o o r , f r o m n e a r t h e d o o r t o a p o s i t i o n b e t w e e n t h e two l o w e r vent openings. Another i n t e r e s t i n g r e s u l t of t h e t e s t s a s r e v e a l e d by a c o m p a r i s o n of c u r v e s 11 and 16 is t h a t although t h e h i g h e r c a p a c i t y " P o d e t t e " h e a t e r supplied about t h r e e t i m e s a s m u c h h e a t a s t h e "Hot B l a s t " s t o v e when l o c a t e d u n d e r t h e hood, a s i n d i c a t e d by the t e m p e r a t u r e c u r v e s , t h e c a r b o n dioxide c o n c e n t r a t i o n s w e r e v i r t u a l l y t h e s a m e f r o m f l o o r t o c e i l i n g . It could be a s s u m e d f r o m t h i s t h a t t h e i n c r e a s e d flow of a i r out t h e unhooded t o p vent d u e t o t h e h i g h e r v e n t i l a t i o n r a t e u s i n g the b i g g e r h e a t e r w a s j u s t s u f f i c i e n t t o o f f s e t t h e g r e a t e r a m o u n t of s p i l l - o v e r of c o m b u s t i o n g a s e s f r o m t h e hood u n d e r which t h e two u n i t s w e r e s e p a r a t e l y p l a c e d . Undoubtedly, t h e s p a c e r e l a t i o n s h i p between h e a t e r s a n d t h e hood, a s w e l l a s t h e s i z e and d e s i g n of t h e hood had a m a r k e d influence on t h e

s h a p e and position of both t e m p e r a t u r e and c a r b o n dioxide p l o t s of c u r v e s 11 and 16. CONCLUDING DISCUSSION T o r e l a t e t h e r e s u l t s of t h e s e t e s t s t o a c t u a l s i t u a t i o n s within a conventional f a m i l y f a l l o u t s h e l t e r l o c a t e d in a b a s e m e n t , one m u s t r e c o g n i z e t h a t the a p p r o x i m a t i o n i s n e c e s s a r i l y r o u g h . T h e h e a t l o s s e s f r o m t h e w a l l s , c e i l i n g and f l o o r of t h e t e s t s t r u c t u r e m a y d i f f e r s o m e w h a t f r o m t h e r e a l s i t u a t i o n , t h e p a t t e r n of a i r c u r r e n t s and e v e n t h e b e h a v i o u r of t h e k e r o s e n e - b u r n i n g a p p l i a n c e s m a y c h a n g e . N e v e r t h e l e s s , i f t h e whole t e m p e r a t u r e l e v e l w a s r e d u c e d by t h i r t y d e g r e e s , s o a i r e n t e r i n g the l o w e r v e n t s w a s about 4 3 ° F i n s t e a d of 7 3 " F , which would be t y p i c a l of a w i n t e r t i m e b a s e m e n t t e m p e r a t u r e , t h e t e m p e r a t u r e c u r v e s c o n t a i n e d h e r e i n b e c o m e m o r e o r l e s s r e p r e s e n t a t i v e of t h o s e t h a t could be e x p e c t e d f o r t h e v a r i o u s h e a t e r s i t u a t i o n s outlined. Although f i r m c o n c l u s i o n s d i r e c t l y a p p l i c a b l e t o t h e r e a l s i t u a t i o n a r e difficult t o obtain f r o m t h e s e t r i a l s i n t h e m o c k - u p of a b a s e m e n t fallout s h e l t e r , c e r t a i n l i m i t e d c o n c l u s i o n s c a n be d r a w n .

( a ) T e t n p e r a t u r c s and I l e a t i ~ ~ g

S m a l l open - f l a m e h e a t c r s p r o v i d e m u c h of t h e i r h e a t output in the r i s i n g Ilot g a s s t r e a r n s which a l s o include t h e g a s e s of c o r n b ~ l s t i o t ~ . A _{high d e g r e e of s t r a t i f i c a t i o n of t e m p e r a t u r e i s} i t ~ e v i t a l , l e . T h i s i s f u r t h e r p r o r n o t e d by t h e r e l a t i v e l y high

v e n t i l a t i o n r a t e a m o u n t i n g t o about 8 a i r c h a n g e s p e r h o u r which d o m i n a t e s t h e t e m p e r a t u r e r e g i m e a t l o w c r l e v e l s .

S o m e i m p r o v e m e n t c a n be a c h i e v e d by the u s e of h e a t e r s of t h e r a d i a n t t y p e when the r a d i a n t p a r t of t h e i r output c a n be d i r e c t e d t o l o w e r l e v e l s .

T h e v e n t i l a t i o n h e a t l o s s i s r e l a t i v e l y h i g h , w i t h fixed o p e n i n g s f o r gra.vity v e n t i n g , due both t o t h e high v e n t i l a t i o n r a t e and the f a c t t h a t t h e a i r e x h a u s t e d i s d r a w n f r o m t h e u p p e r l e v e l s and i s t h e r e f o r e m u c h above t h e m e a n s h e l t e r t e m p e r a t u r e .

M e c h a n i c a l s t i r r i n g could r e d u c e t h e t e m p e r a t u r e g r a d i e n t , but t h i s would have t o be p r o v i d e d by hand a s no o t h e r p o w e r would b e a v a i l a b l e .

T h e v e n t i l a t i o n h e a t l o s s , being t h e p r o d u c t of t e m p e r a t u r e and flow r a t e i s not l i n e a r with t e m p e r a t u r e , s i n c e flow r a t e

i n c r e a s e s r o u g h l y a s t h e s q u a r e r o o t of t h e t e m p e r a t u r e d i f f e r e n c e . I n c r e a s i n g t h e h e a t input t h u s p r o d u c e s l e s s t h a n a c o r r e s p o n d i n g i n c r e a s e in t e m p e r a t u r e

,

t h e v e n t i l a t i o n o p e n i n g s r e m a i n i n g fixed a n d u n o b s t r u c t e d . T h e l o w e r t h e h e a t e r s a r e l o c a t e d , and the c l o s e r t h e y a r e t o t h e i n c o m i n g a i r o p e n i n g s the g r e a t e r i s t h e o p p o r t u n i t y f o r m i x i n g and t h u s f o r t h e l o w e s t p o s s i b l e v e r t i c a l t e m p e r a t u r e g r a d i e n t . T h e u s e of a s i m p l e h e a t e x c h a n g e r of s u b s t a n t i a l a r e a , but w i t h u n c o n t r o l l e d induced a i r flow t h r o u g h i t d o e s not r e s u l t in a n i m p r o v e d t e m p e r a t u r e g r a d i e n t . T h e r e s u l t i n g t e m p e r a t u r e s w e r e s o m e w h a t l e s s a t a l l l e v e l s c o m p a r e d t o the s a m e a r r a n g e m e n t of h e a t e r s o p e r a t e d without the e x c h a n g e r i n d i c a t i n g a l o w e r h e a t i n g e f f e c t . T h i s m i g h t have b e e n i m p r o v e d with c o n t r o l l e d a i r flow a s i n a p r o p e r s t o v e , r e s u l t i n g in a s o m e w h a t h i g h e r e x c h a n g e r

s u r f a c e t e m p e r a t u r e . T h e r e w a s n o i n d i c a t i o n of a n y i m p r o v e m e n t t h r o u g h i n c r e a s e d r a d i a t i o n f r o m t h e e x c h a n g e r .

It i s u n l i k e l y t h a t p r o p e r l y vented c l o s e d s t o v e s w i l l

i m p r o v e m e n t d u e t o i n c r e a s e d r a d i a t i v e h e a t t r a n s f e r i s l i k e l y t o be offset by the h i g h e r s t a c k l o s s e s due t o h i g h e r flue g a s t e m p e r a t u r e s at d i s c h a r g e .

T h e u s e of a t a b l e l o c a t i o n f o r a s t o v e , w i t h a s m a l l hood o v e r i t c a n r e d u c e t h e h e a t i n g e f f e c t m a r k e d l y a n d would be d e s i r a b l e f o r cooking i n s u m m e r . T h e r e w a s e v i d e n c e of s o m e

s p i l l a g e of g a s e s f r o m t h e hood w i t h only one s t o v e , i n d i c a t i n g t h e n e e d f o r g r e a t e r d e p t h of hood b e l o w t h e o u t l e t v e n t s in o r d e r t o e n s u r e a d e q u a t e c h i m n e y e f f e c t f o r t h e d e s i r e d flow.

( b ) C a r b o n Dioxide and V e n t i l a t i o n

T h e r e i s , i n g e n e r a l , a c l o s e c o r r e s p o n d e n c e b e t w e e n t e m p e r a t u r e r i s e due t o h e a t i n g and c a r b o n dioxide c o n c e n t r a t i o n , t h e g r e a t e s t d i v e r g e n c e b e i n g a t t h e l o w e r l e v e l s . T h e v e n t i l a t i o n of t h e s h e l t e r i s q u i t e a d e q u a t e t o r e s t r i c t t h e i n c r e a s e i n c a r b o n d i o x i d e t o 0 . 2 5 p e r c e n t a t a f u e l b u r n i n g r a t e c o r r e s p o n d i n g t o about 4 0 0 0 ~ t u / h r p l u s 5 o c c u p a n t s , and i s p a r t l y self - r e g u l a t i n g , i n c r e a s i n g w i t h i n c r e a s e d f u e l b u r n i n g r a t e . T h e u s e of a s i m p l e h e a t e x c h a n g e r without c o n t r o l l e d a i r flow c a n g r e a t l y r e d u c e the c a r b o n dioxide c o n c e n t r a t i o n by d e l i v e r i n g t h e g a s e s u n d e r the hood a t t h e u p p e r v e n t s . T h i s m a y be of l i t t l e c o n s e q u e n c e , h o w e v e r , i f t h e b a s e m e n t v e n t i l a t i o n r a t e and t h u s t h e c a r b o n dioxide content of t h e a i r e n t e r i n g t h e s h e l t e r , r a t h e r t h a n t h e i n c r e a s e within t h e s h e l t e r , b e c o m e s the l i m i t i n g c o n s i d e r a t i o n . T h e v e n t i l a t i o n r a t e s c a n be c a l c u l a t e d u s i n g o r i f i c e t h e o r y , t h e h e a d being d e t e r m i n e d on t h e b a s i s of the i n t e g r a t e d d e n s i t y d i f f e r e n c e s b e t w e e n t h e l e v e l s of i n l e t s a n d o u t l e t s , a n d a r e q u i t e c l o s e l y a p p r o x i m a t e d f o r t h e c o n c r e t e b l o c k s u s e d by a n o r i f i c e c o e f f i c i e n t of 0.

6

T h e p r e s e n t s t u d y h a s b e e n c o n c e r n e d only with c a r b o n d i o x i d e c o n c e n t r a t i o n s , which a r e r e l a t e d t o f u e l b u r n i n g r a t e , a n d not w i t h c a r b o n monoxide p r o d u c t i o n , w h i c h i s t o b e t h e s u b j e c t of a l a t e r s t u d y and r e p o r t .

R E F E R E N C E S ( 1 ) K e n t , A . D. a n d N . B . I3r1tcheon. B a s e m e n t f a l l o u t s h e l t e r c l i m a t e s t u d i e s , 1961. N a t i 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 of Building R e s e a r c h , I n t e r n a l R e p o r t N o . 243, O t t a w a , J a n u a r y 1962. ( 2 ) K e n t , A . D . , N. B . H u t c h e o n , G. T . T a m u r a a n d G. 0. H a n d e g o r d . B a s e m e n t . f a l l o u t s h e l t e r c l i m a t e s t u d i e s , J a n u a r y - F e b r u a r y 1962. N a t i 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 of B u i l d i n g R e s e a r c h , I n t e r n a l R e p o r t No. 264, O t t a w a , A p r i l 1963.

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T w o " h o t b l a s t " s t o v e s o n f l o o r ( n o f l u e p i p e ) 6 - T w o " h o t b l a s t " s t o v e s o n f l o o r b o t h u s i n g h e a t e x c h a n g e r a s f l u e p i p e 7 - T w o " h o t b l a s t " s t o v e s o n e o n f l o o r a n d o n e o n t a b l e u n d e r h o o d ( n o f l u e p i p e i 8 - T w o " h o t b l a s t " s t o v e s b o t h o n t a b l e u n d e r h o o d ( n o f l u e p i p e i 9 - T w o " h o t b l a s t " s t o v e s b o t h o n t a b l e u n d e r u n h o o d e d v e n t s I n o f l u e p i p e ) F I G U R E 9 M O C K - U P F A L L O U T S H E L T E R T E M P E R A T U R E A N D C A R B O N D l O X l DE C O N C E N T R A T I O N G R A D 1 E N T S na 7 4 7 7 - 1

U s i n g s i n g l e " H o t B l a s t " s t o v e a n d " P o d e t t e " h e a t e r a t 2000 B t u l h r a n d 6 0 0 0 B t u l h r r e s p e c t i v e l y C u r v e 1 0 - " h o t b l a s t " s t o v e o n f l o o r 11 - " h o t b l a s t " s t o v e o n t a b l e u n d e r h o o d 13 - " h o t b l a s t " s t o v e o n f l o o r u s i n g h e a t e x c h a n g e r a s f l u e p i p e 1 4 - " P o d e t t e " h e a t e r o n f l o o r ( P o s i t i o n 1 a t d o o r ) 1 5 - " P o d e t t e " h e a t e r o n f l o o r ( P o s i t i o n 2 b e t w e e n v e n t s ) 1 6

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T h e s e t e s t s r u n i n S e p t . 163 as a r e r u n o f t e s t s o f M a r c h - M a y 1 6 2 u s i n g " H o t B l a s t " s t o v e s at 2000 B t u l h r e a c h . Hood r e m o v e d f r o m top v e n t . C u r v e B10 - O n e s t o v e o n f l o o r

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