Temperature and humidity in school classrooms, Halifax 1961-1962

Publisher’s version / Version de l'éditeur:

Vous avez des questions? Nous pouvons vous aider. Pour communiquer directement avec un auteur, consultez la

première page de la revue dans laquelle son article a été publié afin de trouver ses coordonnées. Si vous n’arrivez pas à les repérer, communiquez avec nous à PublicationsArchive-ArchivesPublications@nrc-cnrc.gc.ca.

Questions? Contact the NRC Publications Archive team at

PublicationsArchive-ArchivesPublications@nrc-cnrc.gc.ca. If you wish to email the authors directly, please see the first page of the publication for their contact information.

https://publications-cnrc.canada.ca/fra/droits

L’accès à ce site Web et l’utilisation de son contenu sont assujettis aux conditions présentées dans le site LISEZ CES CONDITIONS ATTENTIVEMENT AVANT D’UTILISER CE SITE WEB.

Internal Report (National Research Council of Canada. Division of Building Research), 1963-06-01

READ THESE TERMS AND CONDITIONS CAREFULLY BEFORE USING THIS WEBSITE.

https://nrc-publications.canada.ca/eng/copyright

NRC Publications Archive Record / Notice des Archives des publications du CNRC :

https://nrc-publications.canada.ca/eng/view/object/?id=b9023136-702e-4328-ad79-286476ab63f9 https://publications-cnrc.canada.ca/fra/voir/objet/?id=b9023136-702e-4328-ad79-286476ab63f9

NRC Publications Archive

Archives des publications du CNRC

For the publisher’s version, please access the DOI link below./ Pour consulter la version de l’éditeur, utilisez le lien DOI ci-dessous.

https://doi.org/10.4224/20337962

Access and use of this website and the material on it are subject to the Terms and Conditions set forth at

Temperature and humidity in school classrooms, Halifax 1961-1962

NATIONAL RESEARCH COUNCIL CANADA

D I V I S I O N OF BUILDING

RESEARCH

TIMPERATUEIE AND HUMIDITY I N SCHOOL CLASSROOMS, HALIFAX

1961-1962

b y D. R. R o b s o n

Internal

R e p o r t 30.

265

of the 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 OTTAWA

JUNE 1963

TEMPERATTmE AND HIJh1IDITY I N SCHOOL CLASSROOMS, HALIFAX 1961-1962

D. R. Robson

I n October 1961 t h e temperature and h u n i d i t y s t u d y program t h a t had been i n progress i n some houses i n t h e

H a l i f a x a r e a was expanded t o i n c l u d e s i x s c h o o l s i n t h e c i t y of Halifax. The s i x s c h o o l s were l o c a t e d w i t h i n a l&-mile r a d i u s o f t h e A t l a n t i c Regional S t a t i o n and were chosen i n c o n s u l t a t i o r ~ w i t h t h e school s u p e r v i s o r . The s t u d y a s o r i g i n a t e d i n October 1961 was c a r r i e d on throughout t h e w i n t e r u n t i l June 1962.

The indoor r e c o r d s of temperature and r e l a t i v e

humidity were obtained by means o f a hygrothernograph (Figure 1) which c o n s i s t s of a cloclc-driven 7-day drum c h a r t on which

a r e recorded changes i n r e l a t i v e humidity r e g i s t e r e d by a h a i r element and changes i n temperature r e g i s t e r e d by a b i m e t a l element. Because t h e h a i r element cannot be r e l i e d upon f o r accuracy over a wide range of humidity, t h e hygro- thermographs were c a l i b r a t e d weekly u s i n g a n e l e c t r i c a l l y a s p i r a t e d psychrometer. The hygrothermograph was l o c a t e d a t t h e 30-in. l e v e l , removed from d i r e c t d r a u g h t s ,

The outdoor r e c o r d s o f temperature and r e l a t i v e humidity were obtained f o r t h e H a l i f a x Weather S t a t i o n from published d a t a of t h e Meteorological Branch, Department of Transport.

A photograph of each school i s included ( F i g u r e s

2 t o 7 ) ; of t h e s i x s c h o o l s f i v e a r e of masonry c o n s t r u c t i o n and one i s of wood c o n s t r u c t i o n . A l l t h e schools were heated by h o t - w a t e r h e a t i n g systems w i t h i n d i v i d u a l room c o n t r o l , and used conventional f r e e - s t a n d i n g c a s t - i r o n r a d i a t i o n . None of t h e schools had a v e n t i l a t i o n system i n o p e r a t i o n ;

o u t s i d e a i r was c o n t r o l l e d by opening and c l o s i n g windows, The occupancy of each school classroom v a r i e d from day t o day and i n some classrooms from hour t o hour. The avera e number p e r classroom, however, could be crmsidered a s about

-3.

0 p u p i l s .

The c h a r t s c o l l e c t e d from each school were processed f o r d a i l y average v a l u e s from which weekly average v a l u e s

were c a l c u l a t e d . Occupied and unoccupied p e r i o d s were included i n t h e c a l c u l a t i o n of weekly averages a s v e r y l i t t l e d i f f e r e n c e occurred when only t h e occupied period was considered. The humidity r a t i o was c a l c u l a t e d from t h e weekly average tempera- t u r e and r e l a t i v e humidity. The weekly averages f o r each school were used t o c a l c u l a t e t h e average weekly value f o r a l l s i x schools.

The outdoor weather r e c o r d s were processed f r o m t h e published d a i l y v a l u e s t o o b t a i n weekly a v e r a g e s of t e m p e r a t u r e , r e l a t i v e humidity, and humidity r a t i o .

A s tvro of t h e s t u d y houses were under i n s t r u m e n t a t i o n

d u r i n g t h i s p e r i o d , it was p o s s i b l e t o i n c l u d e t y p i c a l house c o n d i t i o n s a s w e l l f o r comparison.

Temperature ( F i g u r e s 8 ,

9 )

The weekly average i n d o o r temperature which i s t h e mean f o r a l l

six

s c h o o l s h a s been p l o t t e d on t h e same graph a s t h e weekly average outdoor temperature ( F i g u r e 8 ) . The c u r v e s show, a s one would e x p e c t , t h a t v a r i a t i o n s i n t h e out- door -temperatur3 had v e r y l i t t l e e f f e c t on t h e i n d o o r tempera- t u r e a s t h e hea-ting system i n each s c h o o l i s a u t o m a t i c a l l y c o n t r o l l e d .

The weekly average i n d o o r t e m p e r a t u r e f o r each

school h a s been p l o t t e d ( F i g u r e 9 ) f o r t h e period instrumented.

It i s i n t e r e s t i n g t o n o t e t h e wide range of temperatures maintained from one s c h o o l t o a n o t h e r . School No. 2 and School No. 6 have maintained t e m p e r a t u r e s w e l l above 70°F due t o preference of t h e t e a c h e r o r i n a c c u r a t e c o n t r o l of t h e h e a t i n g systems.

R e l a t i v e Humidity ( F i g u r e s 1 0 , 11)

The weekly i n d o o r average R.H, f o r a l l s c h o o l s has been p l o t t e d on t h e same graph a s t h e weekly outdoor average R.H. ( F i g u r e 1 0 ) . A s t h e r e l a t i v e humidity i s a f u n c t i o n of t h e d r y bulb temperature comparisons cannot be made on t h e b a s i s of R.H. a l o n e .

The weekly average R.H. f o r each s c h o o l h a s been

p l o t t e d s e p a r a t e l y ( F i g u r e 11) and a g a i n , because of v a r i a t i o n s i n temperature from one s c h o o l t o a n o t h e r , comparisons cannot be made on t h e b a s i s of R.H. It i s i n t e r e s t i n g t o n o t e ,

however, t h e range of R.H, e x i s t i n g over such a s h o r t time

i n

some of t h e s c h o o l s .

I n s t r u m e n t a t i o n f o r a l - d a y p e r i o d i n one s c h o o l u s i n g a 24-hr c h a r t i n d i c a t e d a n i n c r e a s e i n R.H. of a p p r o x i - mately

1 5 p e r c e n t f o r t h e occupied p e r i o d o v e r t h e unoccupied

Humidity R a t i o ( F i g u r e s 12 and

1 7 )

The a v e r a g e weekly i n d o o r h u m i d i t y r a t i o f o r t h e s i x s c h o o l s h a s been p l o t t e d on -tihe same g r a p h a s t h e a v e r a g e weekly o u t d o o r h u m i d i t y r a t i o ( F - L ~ u r e 1 2 ) . A t h i r d c u r v e h a s been added t o F i g u r e 1 2 r e p r e s e n t i n g t h e weekly house a v e r a g e h u m i d i t y r a t i o f o r t h e two h o u s e s i n s t r u m e n t e d d u r i n g t h i s p e r i o d ,

The i n d o o r c u r v e f o l l o w s t h e o u t d o o r c u r v e because of a i r change between i n d o o r s and o u t d o o r s , The e f f e c t i s more marked i n s c h o o l s t h a n i n homes, p r o b a b l y because of i n c r e a s e d v e n t i l a t i o n i n s c h o o l s , The i n d o o r house a v e r a g e i s h i g h e r t h a n t h e i n d o o r s c h o o l a v e r a g e i n d i c a t i n g a d r i e r atmosphere i n s c h o o l s , The weekly a v e r a g e i n d o o r h u m i d i t y r a t i o f o r e a c h s c h o o l h a s been p l o t t e d a g a i n s t t h e a v e r a g e f o r a l l s i x s c h o o l s t o i l l u s t r a t e t h e v a r i a t i o n of e a c h s c h o o l from t h e a v e r a g e ( F i g u r e

1 ' 3 ) .

CONCLUSIONS From t h i s l i m i t e d s t u d y it a p p e a r s t h a t t h e r e l a t i v e h u m i d i t y i n c l a s s r o o m s i n w i n t e r i s g e n e r a l l y l e s s t h a n i n homes, a s would be e x p e c t e d . The i n d o o r h u m i d i t y r a t i o i s

on t h e a v e r a g e a b o u t t w i c e t h a t o u t d o o r s i n m i d - w i n t e r , emphasizing t h e r o l e of m o i s t u r e g i v e n off by o c c u p a n t s i n d e t e r m i n i n g t h e r e l a t i v e h u m i d i t y . V a r i a t i o n s i n r e l a t i v e h u m i d i t y between c l a s s r o o m s a r e no doubt l a r g e l y due t o v a r i a t i o n s i n v e n t i l a t i o n r a t e a s d e t e r m i n e d by window

o p e r a t i o n ,

ACKNOWLEDGMENTS

The au-thor wishes t o t h a n k t h e H a l i f a x School Board, t h e p r i n c i p a l s of e a c h of t h e s c h o o l s i n v o l v e d , and t h e

i n d i v i d u a l t e a c h e r s . T h e i r i n t e r e s t and c o - o p e r a t i o n made t h i s s t u d y p o s s i b l e .

F i g u r e 1 Hygrothermograph\ w i t h guard removed and c a s e open.

Figure 2 S c h o o l No. 1

F i g u r e 4 _{School No.}

₃

F i g u r e 6 Schocl No.

5

/

A V E R A G E /r2/000Q 7-EM,PEQAJUqE 6 S C H O O L S V 5 A V E A A G E OUTDOOq JEM,D&qArUq& -% -

-

1 0

-2.

- 5' 20 -25

So

-25

O C T P E L JarJ F E B MA4 Apq MAY

F/LL/AE //

AVEGAGL I1'EEC;LY CjL L A T I l/tT L f U f i / / p / f / & S SCHOOLS / - 6

O C T 3 € C J A N IL'E &k'S 80 70 60 50 ALL SCNOD 40 30 20 10 0 5 1 0 /f 2 0 3 LO-2