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The Design of Research Laboratories, Pt. I. A General Assessment. Pt.
II. Air Conditioning and Conditioned Rooms
Ser TIi]-N2r-t2 nr. 2l"O e . 2 BIDG
NATIONAL RESEARCH COUNCIL CANADA
DIVISION OF BUILDING RESEARCH
THE DESIGN OT' RESEARCH LABORATOzuES oy
R.I'. Legget and N. B. Hutcheon
P a r t I : A G e n e r a l A s s e s s r n e n t b y R . F . L e g g e t Part II: Air-Conditioning and Conditioned
R o o m s b y N . B . H u t c h e o n
A I : , & L ' 1 2 i l 0
Presented at the Second Annual Conference of the Canadian Research Managernent Association,
held in Ottawa, 3 Novernber 1964
T e c h n i c a l P a p e r N o . Z L } of the
Division of Building Research
OTTAWA
Part I Part I I Appendix
THE DESIGN OF. RESEARCH LABORATORIES
A G e n e r a l A s s e s s m e n t b y R . F , L e g g e t "
Air-Conditioning and Conditioned Rooms by N. B. Hutcheon.
An Annotated Bibliography on Laboratory Bpildings
c o m p i l e d b y A . B r a s s . 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 o f B u i l d i n g R e s e a r c h , B i b l i o g r a p h y N o . 1 6 , Jr:ne l9 59 .
THE DESIGN OF RESEARCH LABORATORIES
P A R T I : A G E N E R A L A S S E S S M E N T
b y R " F . I - e g g e t D i r e c t o r , D B R / N R C
At the first meeting of the Canadian Research Management A s s o c i a t i o n , a n i n t e r e s t i n g f e a t u r e o f t h e p r o g r a m w a s t h e f r e q u e n t m e n t i o n o f l a b o r a t o r y b u i l d i n g s , n o t o n l y i n s o m e o f t h e p r e p a r e d p a p e r s b u t a l s o i n t h e g e n e r a l d i s c u s s i o n . T h i s w a s n o t r e a l l y s u r p r i s i n g s i n c e a p r i m e r e q u i r e m e n t o f r n a n a g e m e n t i s t h e p r o v i s i o n o f s u i t a b l e a c c o m m o -dation for the proper conduct of work. It was evident, however, that there is currently rather wide interest in Canada in the design of laboratory
b u i l d i n g s f o r r e s e a r c h p u r p o s e s , a r e f l e c t i o n o f t h e g r o w i n g i n t e r e s t i n r e s e a r c h o n t h e p a r t o f C a n a d i a n i n d u s t r y " I t i s n o t i n a p p r o p r i a t e ,
therefore, for the sr:.bject of laboratory buildings to be featured on this s e c o n d a n n u a l p r o g r a m o f t h e A s s o c i a t i o n , e s p e c i a l l y s i n c e t h e m e e t i n g i s b e i n g h e l d i n O t t a w a w h e r e t h e F e d e r a l G o v e r n m e n t h a s , o v e r t h e y e a r s , d e v e l o p e d a n e x t e n s i v e s u i t e o f l a b o r a t o r i e s f o r a v a r i e t y o f s p e c i a l n e e d s .
This part of the meeting is being heid at the MontreaL Road L a b o r a t o r i e s o f t h e N a t i o n a l R e s e a r c h C o u n c i l . T h i s p a r k - l i k e a r e a o f 5 5 0 a c r e s , w i t h m o r e t h a n f o r t y b u i l d i n g s s e r v i n g t h e n e e d s o f t h e C o u n c i l ' s engineering and applied Divisions,is still but little known to Canadians in g e n e r a l a n d y e t i t c o n s t i t u t e s o n e o f t h e m o s t e x t e n s i v e o f s u c h r e s e a r c h e s t a b l i s h m e n t s i n N o r t h A m e r i c a . T h e f i r s t p a r t o f t h e a r e a w a s p u r c h a s e d as two farms, beyond the outskirts of Ottawa, in the years irnmediately p r e c e d i n g t h e S e c o n d W o r l d W a r . E a r l y p l a n n i n g a n d d e v e l o p m e n t w a s a c c e l e r a t e d i n r e s p o n s e t o t h e d e m a n d s o f d e f e n c e r e s e a r c h . P o s t w a r extension of the property, and erection of many additional buildings, has a l l b e e n c a r r i e d o u t t o a n o v e r - a l l p l a n t h a t w i l l r e a c h i . t s f u l l d e v e l o p m e n t when the scientific divisions of the Council move out from the original Sussex Drive building probably within the next decade.
U n t i l 1 9 4 7 , t h e D i v i s i o n o f M e c h a n i c a l E n g i n e e r i n g w a s t h e s o l e u s e r o f t h i s p r o p e r t y . I n t h a t y e a r t h e C o u n c i l s t a r t e d i t s D i v i s i o n o f B u i l d i n g R e s e a r c h a n d D B R w a s t h e f i r s t o f t h e o t h e r p a r t s o f t h e C o u n c i l t o s h a r e i n t h e u s e o f t h i s f i n e a r e a . T h e B u i l d i n g R e s e a r c h C e n t r e - t h e c o r n p l e x o f b u i l d i n g s s e r v i n g D B R / N R C - o c c u p i e s a c e n t r a l p o s i t i o n , a d j a c e n t t o
the main road" It houses a part of the Councilts operations related to the c o n s t r u c t i o n i n d u s t r y , o n e w h i c h m i g h t t h e r e f o r e b e e x p e c t e d t o h a v e s o m e i n t e r e s t i n r e s e a r c h l a b o r a t o r i e s .
I - Z
In its principal function of providi.ng a research service to the construction industry of Canada, DBR/NRC has attempted to take a broad view of its responsibilities, recognizing not only the geographical distri-bution of its work but also the principal divisions into which new construction in Canada may be broken down. Residential construction, for example, represents almost 50 per cent of all new building; housing research has therefore had due priority. There are, however, other important groups of buildings such as schools and hospitals, in addition to commercial and industrial buildings, that are readily identifiable. It is our hope gradually to develop basic information regarding the changing functional requirements of all such major groups. You will not be surprised to know that we started on this phase of our work by a study of a functional group rather close to our own special interests, namely laboratory buildings.
Unfortunately for us, we had just got well started on this pilot study when the architect who was spending full time on it left the Division to take up further study in Toronto. Because of the austerity conditions that were imposed just at that time upon the public service of Canada, we were unable to carry on with the work. Accordingly, we have no finished and comprehensive studies as yet, with no guide-Iine papers other than an annotated bibliography (which accompanies this two-part paper). The subject is so vast that all we can do in this paper is to touch upon some of the more important aspects of the planning of research laboratories, and t h e n d i s c u s s i n m o r e d e t a i l s o m e o f t h e m o r e p r e s s i n g a s p e c t s o f t h e s e r v i c e s n e c e s s a r y i n s u c h b u i l d i n g s , a s p e c t s t h a t w e k n o w a r e n o t a s w e l l appreciated as they should be in the planning of new laboratories.
LOCATION
There are so many diverse factors affecting the location of any o n e l a b o r a t o r y t h a t g e n e r a l c o m r n e n t m i g h t s e e m p o i n t l e s s . f f i t b e r e c o g -n i z e d , h o w e v e r , t h a t a r e s e a r c h l a b o r a t o r y i s g o i -n g t o b e t h e c e -n t r e o f a search for new knowledge, and not just an adjunct of a plant's testing and c o n t r o l l a b o r a t o r y , t h e n s o m e n e w f a c t o r s e n t e r t h e p i c t u r e . T h e d e s i r a -b i l i t y o f r e s e a r c h s c i e n t i s t s h a v i n g r e a d y a s s o c i a t i o n w i t h o t h e r r e s e a r c h workers rnay prove to be more important than their proximity to workers in their own industry. This is well shown by the success of the new " r e s e a r c h p a r k s r t s u c h a s t h a t n o w d e v e l o p i n g o n t h e o u t s k i r t s o f T o r o n t o , and that at Pointe Glaire, outside Montreal. Not only does the close
a s s o c i a t i o n o f g r o u p s o f r e s e a r c h w o r k e r s b r i n g i t s o w n b e n e f i t s b u t s p e c i a l s e r v i c e s c a n b e s h a r e d , a n d b u i l d i n g s s e r v e d w i t h t h e i r o p e r a t i n g n e e d s f r o m a c e n t r a l p l a n t .
r - 3
All these features are well illustrated at these Montreal Road Laboratories and will be similarly reflected in the new laboratories of the National Bureau of Standards, now being developed on an area very similar to this outside Wadrington, D. C. Almost all the buildings on the NRC property are interconnected by a system of walk-in tunnels (almost two miles in all) not only facilitating the provision of services to all buildings from the central heating plant, but providing convenient human access at time of bad weather. Admittedly these points are rather obvious when so baldly stated, but I sometimes remember an extreme case where they were not considered. In a country that must be nameless, a new suite of research laboratory buildings was located each in a different city for what appeared to be the best of reagons. I must leave to your imagination the feelings on this aspect of the location of laboratory buildings of the
great man who, until recently, was in charge of this complex - as he faced the impossible problem of visiting seventeen widely scattered cities in order merely to see his scientific staff, each group isolated from all the o t h e r s .
FUTURE EXPANSION
R e s e a r c h b e i n g w h a t i t i s - - a v e n t u r e i n t o t h e u n k n o w n - - w h e n a research laboratory is planned it is impossible to foresee what will be its ultimate development. It appears to us to be essential, therefore, to allow for expansion in even the initial phases of planning - by providing enough space around a building, and by planning the building itself so that, i f n e c e s s a r y , i t c a n b e r e a d i l y e x p a n d e d . T h i s r e q u i r e s v i s i o n . L e t m e instance the vision of General A. G. L. McNaughton and Dr. J. H. Parkin, when they arranged to purchase the original two farms that gave the 150 acres of this property. They tried to purchase double that area, open f a r m l a n d a s i t t h e n w a s , l e s s t h a n t w e n t y y e a r s a g o . A r n o r e r e c e n t
example is provided by the new DOMTAR research laboratory at Senneville, on a site as beautiful as it is extensive.
There is naturally a limit to which buildings themselves can be expanded. It will often be found, however, that by a very small initial expenditure essential services can be so arranged that, in addition to providing for the initial phase of a building, they can be used in other ways until the building is extended. In our own case, our original electrical
substation had a capacity far in excess of our needs. It was used to provide electrical service to other adjacent buildings until the time came when these buildings had their own supply, and we needed the full capacity of the
I - 4
In the physical planning of buildings, it is usually possible so to arrange the main elements of the plan, by careful off-setting in layout, s o t h a t o n e o r o t h e r s e c t i o n c a n b e e x t e n d e d i f n e c e s s a r y w i t h o u t i n t e r
-fering with the rest of the building. In initial planning, this sort of arrange-ment is easy to achieve, Once a building is up, however, it i8 difficult, if not irnpossible, to achieve. In a structural laboratorY, for example, if an extension of its length may conceivably be necessary in the future, the end columns can be designed and installed as regular columns, with crane-r a i l b crane-r a c k e t s , e t c . , i n p l a c e , a n d a n e n d w a l l t h a t c a n b e crane-r e a d i l y crane-r e m o v e d if it is so placed that no part of the building lies in the line of possible
extension. Correspondingly, it is not an expensive matter so to design and install the structural frame of a building that additional storeys may be easily added in the future, whereas it can be a costly matter to attempt to add storeys to a building in which this provision was not made. The W e s t S i d e b u s t e r m i n a l i n N e w Y o r k ( o n 4 l s t S t r e e t ) s h o w s t h a t s u c h a j o b can be done, but if you will take a glance at its new top storey when next you are in its vicinity, you will see what a complex and expensive addition this was, fascinating though the fine solution is from the structural
engineering point of view.
INTERNAL FLEXIBILITY
T h e n a t u r e o f r e s e a r c h g i v e s i t s u c h a f l u i d c h a r a c t e r t h a t t h e detailed floor planning of a laboratory is an unusually difficult rhatter. S i n c e , a s h a s b e e n s o w e l l s a i d , " I f y o u k n o w w h e r e y o u a r e g o i n g i t i s n r t r e s e a r c h , I t o n e c a n n e v e r b e s u r e t h a t t h e i n i t i a l s p a c e r e q u i r e m e n t s f o r a r e s e a r c h l a b o r a t o r y w i l l c a r r y e v e n t h e s a m e p r i o r i t i e s w i t h i n t h e s p a c e o f a f e w y e a r s , A l l o w a n c e f o r c h a n g e m u s t , t h e r e f o r e , b e a n i n t e g r a l part of the initial plan. This can be achieved in two main ways. If it can be reasonably assumed that the over-alI character of the work to be done in the building is not going to change, then flexibility can be achieved by a minimum of internal subdivision, Iarge open areas being so located that they are convenient to one another, subdivision being carried out by partitions that can readily be moved. In this w?11, a very economical use of space can be achieved, with corridors largely eliminated and the inevitable loss of usable space that every door involves greatly reduced.
On the other hand, 'if flexibility of a more general kind is desired, then the more common idea of having small unit laboratories, arranged to open off corridors in the conventional wayr may prove to be the best solution, despite the loss of effective space that this type of layout
I - 5
involves. You will be able to see good examples of both systems in this building which houses the Radio and Electrical Engineering Division of NRC (illustrative of the latter approach), and the Building Research
Centre (showing the former solution). Let me be the first to admit, however, that it would be difficult, if not impossible,effectively to use our building for any purpose other than building research.
PROVISION OF SERVICES
M e c h a n i c a l a n d e l e c t r i c a l s e r v i c e s a r e a n e s s e n t i a l r e q u i r e m e n t i n a l l r e s e a r c h l a b o r a t o r i e s . T h e i r p r o v i s i o n m u s t t h e r e f o r e b e r e c o g n i z e d from the very start of building planning. They are not something that can be t'fitted inil to the general plans of the architect - as all good architects k n o w . W h e n y o u c o n s i d e r , f o r e x a m p l e , t h a t t h e c o s t o f t h e s e s e r v i c e s will probably amount to 40 per cent of the total cost of the building, and
may be even higher than thatr 1rou will appreciate that they must be care-fully considered and planned as an integral part of the whole structure. They, too, must be flexible since, if individual laboratory units change their function, dernands for services rnay change too. Convenience of a c c e s s t o a l l s e r v i c e s i s , t h e r e f o r e , a v i t a l r e q u i r e m e n t .
I n o l d e r b u i l d i n g s , o r i n b u i l d i n g s a d o p t e d f o r r e s e a r c h u s e s , there is probably no one feature of building operation that causes so much trouble as the need to get at service connections. If the place of services is fully recognized, then the analogy to the installation of services in a large ship is useful. Once this idea is mentioned, the similarity wiII be obvious. Space can be assigned to services on each floor, not tucked away around columns, or merely fitted in to finished floor areas, but floor
s p a c e r e g u l a r l y a s s i g n e d t o v e r t i c a l s e r v i c e s , o p e n b e t w e e n f l o o r s , w i t h the necessary provisions for fire prevention in the absence of the fire s e p a r a t i o n p r o v i d e d b y s o l i d f l o o r s .
Last year, rnany of us saw how elegantly this idea had been incorporated into the new Noranda Research Centre at Pointe Claire, e v e n t o t h e u s e o f t r a n s p a r e n t w a s t e p i p e s , t h u s g i v i n g e v e n m o r e e a s e i n m a i n t e n a n c e . I n t h e B u i l d i n g R e s e a r c h C e n t r e i s a n e a r l i e r v e r s i o n o f the same idea that we can recommend without reservation, an area of about 8 ft by 20 ft on each floor of the main extension to the building, open from the basement to the machinery penthouse, providing ample s p a c e f o r a l l s e r v i c e s , w i t h e a s y a c c e s s t h r o u g h t h e u s e o f o p e n s t e e l flooring, the appearance of which has led the area to be known colloquially a s r r t h e e n g i n e r o o m r r .
r - 6
LABORATORY FURNISHINGNot only must the main provision of services be flexible, but their use in individual laboratories must be similarly adaptable. Let me confine my cornments here to stressing again the importance of flexibility, It is quite surprising to find so many and so diverse views o n t h i s s u b j e c t . W h e n w e e q u i p p e d t h e B u i l d i n g R e s e a r c h C e n t r e w e imagined that all we would have to do would be to order standard
Iaboratory benches and fittings" But we ended up by designing our own, a s s e e m s t o b e a l m o s t u n i v e r s a l p r a c t i c e l W e c a n , h o w e v e r ' a d d t h a t o u r i d e a s h a v e b e e n c o p i e d w i d e l y . T h e y m a y b e s u m m a r i z e d b y s a y i n g t h a t a l l s e r v i c e s a r e i n s t a l l e d a l o n g w a l l s o r p a r t i t i o n s , i n d e p e n d e n t o f t h e b e n c h e s t h e m s e l v e s ' T a p s , o u t l e t b o x e s , e t c . , a r e a l l a r r a n g e d o n 6 - i n . - w i d e s e r v i c e s t r i p s w h i c h a r e f i r m l y s e c u r e d t o t h e f l o o r b y m e t a l s u p p o r t s , t h e s t r i p s s o designed that they fit tightly to the benches and other unit furniture when i t i s m o v e d i r r t o p l a c e a g a i n s t t h e m . A c c e s s t o s e r v i c e s c a n b e g a i n e d without any delay merely by pulling out one unit of the bench furniture.
I N T E R N A L T R A F F I C
O n c e t h e u n i t s t h a t a r e t o b e a c c o m m o d a t e d i n a r e s e a r c h Iaboratory are known, a further important feature of initial planning is t h e c o n s i d e r a t i o n o f t h e i n t e r - r e l a t i o n b e t w e e n t h e v a r i o u s g r o u p s . T h i s is most conveniently done by means of a simple flow diagram, blocks
r e p r e s e n t i n g t h e v a r i o u s u n i t s , c o l o u r e d l i n e s t h e a n t i c i p a t e d f l o w b e t w e e n r e s p e c t i v e g r o u p s . T h e p a t t e r n o f o v e r - a l l t r a f f i c w i I I p r o b a b l y b e c o m e c l e a r f r o m e v e n s u c h a s i m p l e g r a p h i c a l a i d a s t h i s . T h e l i b r a r y w i l l be found, in all probability, to be the focal point for much internal
m o v e m e n t . S h o p s w i l l s h o w t h e m s e l v e s a s c e n t r a l u n i t s t o l a b o r a t o r y
o p e r a t i o n s . T h e s e a n d s i m i l a r c o r r e l a t i o n s w i l l a i d g r e a t l y i n t h e p r e p a r a -t i o n o f i n i -t i a l f l o o r l a y o u -t s . T h e p l a c e o f t h e l i b r a r y w i l l c a l l f o r s p e c i a l a t t e n t i o n . I t h a s b e e n w e l l s a i d t h a t a l l r e s e a r c h s t a r t s i n a l i b r a r y . When it is recalled that the volurne of technical literature is now doubling e v e r y e i g h t t o t e n y e a r s , w i t h a c o r r e s p o n d i n g i n c r e a s e i n t h e n e c e s s a r y capacity of even existing libraries, the need for flexibility in planning, and careful location for the library will be obvious.
T r a f f i c i n a r e s e a r c h l a b o r a t o r y i n v o l v e s n o t o n l y t h e r n o v e m e n t o f p e o p l e , b u t t h e t r a n s f e r o f b o o k s , e q u i p m e n t , s a m p l e s , a n d m a n y o t h e r i t e m s f o r w h i c h t h e u s e o f w h e e l e d t r u c k s i s c o n v e n i e n t . A d e t a i l o f
r - 7
o v e r - a l l l a y o u t i s t o p r o v i d e f o r s u c h i n t e r n a l w h e e l e d t r a f f i c b y t h e e l i m i n a t i o n , i f p o s s i b l e , o f c h a n g e s i n l e v e l o n e a c h f l o o r , t h u s e l i m i n a t i n g t h e n e e d f o r r a m p s o r s i n g l e s t a i r s . T h i s w i l l b e f o u n d t o b e a g r e a t c g n -v e n i e n c e n o t o n l y f o r r e s e a r c h w o r k , b u t i n a n o t h e r w a y t h a t w e h a d n e -v e r r e a l i z e d w h e n w e i n c o r p o r a t e d t h i s f e a t u r e i n o u r o w n b u i l d i n g . R e c e n t l y w e h a d t h e p r i v i l e g e o f c o n v e n i n g a m e e t i n g t o d i s c u s s the developrnent of standards for building requirernents for handicapped c i t i z e n s . F o u r o f t h o s e a t t h i s m e e t i n g w e r e i n w h e e l c h a i r s . O n e f e a t u r e o f t h e s t a n d a r d s t h a t h a v e n o w b e e n d e v e l o p e d , ( S u p p l e m e n t N o . 7 t o t h e National Buiiding Code) is the elimination of ramps. I can leave to your i r n a g i n a t i o n w h a t a p l e a s u r e i t w a s t o c o n d u c t t h e s e f o u r v i s i t o r s , i n t h e i r c h a i r s , a r o u n d o u r l a b o r a t o r i e s , o n e v e r y f l o o r , a n d e v e n i n t o o u r s e r v i c e tunnel. I mention this not only as a matter of interest, but as a further n e c e s s a r y d e s i g n f e a t u r e . T h e r e a r e n o w o v e r h a l f a m i l l i o n o f r e a l l y h a n d i c a p p e d c i t i z e n s i n C a n a d a " R e s e a r c h l a b o r a t o r i e s s h o r . l l d t a k e t h e i r s p e c i a l n e e d s i n t o a c c o u n t . SPACE REQUIREMENTS W i t h a n o v e r - a l l c o n c e p t i o n o f a r e s e a r c h l a b o r a t o r y d e v e l o p e d , d e t a i l e d p l a n n i n g w i l l c a l l f o r s o m e i d e a a s t o t h e s p a c e n e e d e d b y r e s e a r c h w o r k e r s . I r n m e d i a t e l y a f t e r t h e w a r , t h e C o u n c i l g a v e a t t e n t i o n t o t h i s m a t t e r a n d p u b l i s h e d a r e p o r t , w h i c h w e s t i l l h a v e i n p r i n t , g i v i n g s p a c e f i g u r e s f o r t h e C o u n c i l l a b o r a t o r i e s i n u s e a t t h a t t i m e " T h e a u t h o r o f t h i s m o s t u s e f u l p a p e r i s n o w w e l l k n o w n a s t h e P r e s i d e n t o f A t o m i c E n e r g y o f C a n a d a L t d . , D r . J . L o r n e G r a y . I r V e s t i l l a p p r e c i a t e h i s e a r l y c o n t r i . -b u t i o n t o -b u i l d i n g r e s e a r c h w o r k a n d a r e u s i n g h i s r e p o r t a s t h e s t a r t i n g p o i n t f o r o u r m o r e r e c e n t s t u d i e s . F I i s a n a l y s i s s h o w e d L h a t o n t h e b a s i s o f N R C e x p e r i e n c e , a g r o s s a r e a o f 3 5 0 s q u a r e f e e t p e r w o r k e r ( b a s e d o n t o t a l s t a f f ) s h o u l d b e r e g a r d e d a s a m i n i m u m ; 4 0 0 s q u a r e f e e t g r o s s w a s r e c o m m e n d e d a s a g o o d w o r k i n g f i g u r e , w i t h a 7 0 p e r c e n t u t i l i z a t i o n f a c t o r , f o r a c o m p l e t e r e s e a r c h f a c i l i t y . ! V ' e h a v e r e a s o n t o b e l i e v e t h a t t h e s e f i g u r e s w i l l h a v e t o b e s l i g h t l y i n c r e a s e d i n t h e l i g h t o f m o d e r n n e e d s , b u t t h e y s t i l l r e m a i n a m o s t u s e f u l g u i d e . T h e s p a c e p r o v i d e d i n a r e s e a r c h I a b o r a t o r y t o d a y p e r w o r k e r s h o u l d n o t d e p a r t t o o f a r f r o m t h e s e c r i t e r i a , 5 0 0 s q u a r e f e e t g r o s s p e r p e r s o n c e r t a i n l y b e i n g a l i m i t i n g f i g u r e . Y o u c a n w e l l i m a g i n e h o w a n x i o u s w e a r e t o h a v e u p - t o - d a t e f i g u r e s o f t h i s k i n d . T h i s w i l l b e a n i m m e d i a t e o b j e c t i v e o f o u r s t u d y o f t h e f u n c t i o n a l r e q u i r e r n e n t s o f l a b o r a t o r y b u i l d i n g s w h e n i t i s r e s u m e d .r - 8
BUILDING COSTS
It is even more difficult to be precise with regard to building costs, mainly because of the mounting r:nit cost of building in general consistent with the changing value of money itself. llle do suggest, however, that a first reguirement is for an appreciation of the cost of r e s e a r c h l a b o r a t o r i e s p e r c u b i c f o o t , i n s t e a d o f p e r s q u a r e f o o t a s i s the more common practice. Square foot costs take no account of ceiling heights. In office buildings, this is not very serious since ceiling heights a r e f a i r l y s t a n d a r d . N o t s o i n r e s e a r c h l a b o r a t o r i e s , w h e r e p i l o t a r e a s , special laboratories and other unusual features require quite unusual room shapes. Just as soon as ie possible, we shall publish some guide lines to this unusually important aspect of research laboratory design.
THE DESIGN OF RESEARCH LABORATORIES
PART II: AIR-CONDITIONING AND CONDITIONED ROOMS
rtr{
N . B . H u t c h e o n
A s s i s t a n t D i r e c t o r , D B R / N R C
T h e r n o r e i r n p o r t a n t c o n s i d e r a t i o n s which arise in deciding u P o n t h e a i r - c o n d i t i o n i n g o f a l a b o r a t o r y w i l l n o w b e c o n s i d e r e d with ernphasis on those that have irnplications for the desien of the
l a b o r a t o r y i t s e l f . I t i s i n t e n d e d for those who, though not specialists i n a i r - c o n d i t i o n i n g , r n u s t n e v e r t h e l e s s r n a k e d e c i s i o n s about it.
A i r - c o n d i t i o n i n g i s d e f i n e d a s "the process of treating air so a s t o c o n t r o l s i r n u l t a n e o u s l y i t s t e r n p e r a t u r e , hurnidity, cleanliness, a n d d i s t r i b u t i o n t o r n e e t t h e r e q u i r e f f i e n t s of the conditioned space. " I t i s r e s t r i c t e d b y t h i s definition to air of norrnal cornposition, not i n c l u d i n g t h e r e a d j u s t r n e n t o f the proportions of the gaseous constituents other than water vaPour or the adjustrnent of any other environrnental factors other than those that can be affected by the air as rnay sorrretirnes b e r e q u i r e d i n s p e c i a l l a b o r a t o r y conditioning. T h e r n o r e g e n e r a l
terrn, conditioning, rnay be applied when other factors are involved, The discussion that follows will be concerned rnainly with the sirnul-taneous control of ternperature and humidity both winter and surnrner --t h e a s p e c --t o f a i r - c o n d i --t i o n i n g w h i c h i s r n o s t c o r n r n o n l y o f c o n c e r n .
T h e b e n e f i t s t o b e a c h i e v e d f r o r n air-conditioning of research l a b o r a t o r i e s r n u s t s o m e h o w b e a s s e s s e d a g a i n s t t h e c o s t s o f p r o v i d i n g it. O n a s t r i c t l y b u s i n e s s approach, one rnust consider whether air-cond.rtioning w i l l r e d u c e t h e o v e r - a l l c o s t of getting the job done. This presupposes t h a t t h e b e n e f i t s c a n b e i n d e n t i f i e d , assessed, and reduced to a cornrnon d o l l a r b a s i s f o r c o r n p a r i s o n . I t i s o f t e n d i f f i c u l t t o d o t h i s , r n u c h to the f r u s t r a t i o n o f t h e a i r - c o n d i t i o n i n g industry, even in the case of factories where the output can be rneasured readily. It is rnore difficult for a r e s e a r c h l a b o r a t o r y w h e r e input and output and the processes relating thern are rnuch rnore cornplex and less arnenable to rneasurernent. Despite this, the criterion of effect on output is valid, and judgernent rnust be i n t r o d u c e d w h e r e t h e p e r t i n e n t facts needed for the equation are not c l e a r l y e s t a b l i s h e d .
T h e c a s e f o r a i r - c o n d i t i o n i n g o f l a b o r a t o r i e s r n u s t a l w a y s b e
A .
f i - z
a n d t h e s e c o n d t o t h e r n a t e r i a l s a n d o p e r a t i o n s b e i n g h o u s e d . O n t h i s b a s i s f o u r c l a s s e s o f c o n d i t i o n e d s p a c e w i t h i . n a l a b o r a t o r y r n a y b e d i s t i n g u i s h e d a s f o l l o w s : S p a c e i n w h i c h t h e p r i r n e c o n s i d e r a t i o n i s t h e o c c u p a n t s , o r i n which the requirernents of the occupants are rnore restrictive t h a n t h o s e o f t h e r n a t e r i a l s a n d o p e r a t i o n s "Space in which the conditions are deterrnined by the needs of the rnaterials or operations and are rnore dernanding but are not in conflict with norrnal occupancy.
Space in which the conditions are set by the requirernents of the rnaterials or operations and are in conflict with the cornfort and convenience of occupants but do not prohibit occupancy.
S p a c e i n w h i c h f o r v a r i o u s r e a s o n s t h e c o n d i t i o n s s e t b y t h e r e q u i r e r n e n t s o f t h e r n a t e r i a l s o r o p e r a t i o n s , o r i n c i d e n t a l t o thern, prohibit occupancy.
B "
C .
D .
I t w i l l b e r e c o g n i z e d t h a t t h i s c l a s s i f i c a t i o n c a n b e a p p l i e d t o all the environrnental factors involved in a laboratory, not just those i n v o l v e d i n a i r - c o n d i t i o n i n g w h i c h a r e o f c o n c e r n h e r e . C l a s s D s p a c e w i l l b e r e c o g n i z e d a s v e r y s p e c i a l , i n c l u d i n g t h a t i n w h i c h o n e o r r n o r e of the environrnental factors ate lnazardous to hurnan occupancy, but also those in which occupancy would be in conflict with the conditions t o b e r n a i n t a i n e d . S i n c e s u c h s p a c e i s u s u a l l y c o s t l y i t i s o f t e n p r o v i d e d i n t h e f o r r n o f c a b i n e t s , g l o v e b o x e s , b a t h s , c u p b o a r d s a n d v a u l t s , srnaller t h a n r o o r n s i z e . T h e r e q u i r e r n e n t s a r e u s u a l l y s o r e s t r i c t e d a n d t h e
p o s s i b l e r a n g e o f t h e r n s o g r e a t t h a t n o f u r t h e r attention can usefully be given to thern here. Sorne cornrnents will be offered on warrn and cold r o o t n s w h i c h a r e c o r n r n o n e x a r n p l e s o f c l a s s C s p a c e . T h e d i f f e r e n c e s t h a t c a n a r i s e b e t w e e n t h e a i r - c o n d i t i o n i n g r e q u i r e r n e n t s f o r o c c u p a n t s a n d f o r o p e r a t i o n s , w h i c h a r e t h e b a s i s f o r t h e d i f f e r e n t i a t i o n b e t w e e n t h e f i r s t t w o c l a s s e s , r n e r i t f u r t h e r d i s c u s s i o n .
AIR -CONDITIONING FOR OCCUPANTS
The hurnan body is highly adaptable to changed environrnental conditions, within certain lirnits. Ternperature and hurnidity lirnits for n o r r n a l o c c u P a n c y a r e d e t e r r n i n e d l a r g e l y b y c o n s i d e r a t i o n s o f c o r n f o r t a n d p r a c t i c a l c o n v e n i e n c e r a t h e r t h a n p h y s i o l o g y . T h e s e u s u a l l y f a i L w i t h i n the range of conditions over which the hurnan body is well able to rnake cornpensatory adjrrstrnents without any proven ill effects upon health.
I I - 3
The norrnal, or dry bulb, ternperature for comfort varies with individuals, with work rate or rnetabolisrrr, arnount of clothing, therrnal radiation levels, air rnotion, and relative hurnidity. A range of
ternperature of 5 degrees can be found for people in a given area and season, sirnilarly clothed and equally active within which at least 90 per cent of thern will be cornfortable. There appears to be a shift of as rnuch as 5 degrees in the preferred value frorn winter to surnrner and some effect as well due to average clirnatic conditions. Because of the lnany factors that influence cornfort in addition to ternperature it is difficult to establish any optirnurn values. For people who are sedentary or engaged only in light work the rnost acceptable value would appear to fall between 70 and 75"F in winter and between 75 and 80oF in surnrrrer. There appears however to be an increasing tendency with the widespread p r o v i s i o n o f y e a r - r o u n d air-conditioning to accept ternperatures close to 75" both winter and surnrner. A standard now under developrnent in the United States sets the range at 73 to 77 oF with the relative hurnidity not to exceed 60 per cent air velocities less than 45 fprn, and cornpensation to be provided for Mean Radiant Ternperature effects.
The influence of relative hurnidity on cornfort i.s not well
established. Many years ago the Arnerican Society of Heating, Refrigerating and Air-Conditioning Engineers published an Effective Temperature' Chart which established a relationship between ternperature and relative hurnidity for equal cornfort conditions. This has been and still is widely used, in the absence of any rnore acceBtable guide, despite recent work which shows it to be incorrect when extended beyond the experirnental conditions on which i t w a s b a s e d ( 1 ) ' k . B r i e f t y , i t i n d i c a t e d t h a t f o r t h e s a l n e c o r n f o r t t h e dry bulb ternperature should be reduced as the relative hurnidity increaseq. Later work with lightly clothed subjects at rest or doing only light work under prolonged exposure to the sarne conditions failed to show any effect of relative hurnidity within the cornfort range except where high hurnidities were involved.
Other recent work shows a greater influence of hurnidity for rrrore active subjects than that originally given. It would appear that relative hurnidity enters into therrnal sensations of cornfort rnainly under conditions of work rate and ternperature at which the body resorts to sweating to rnaintain its ternperature. There is, however, a cornplicating transient effect upon a change frorn one relative hurnidity condition to another, due to the adjustrnent of the equilibrium rnoisture content of
I T . 4
clothing and perhaps also to other effects.
Radiant ternperature effects can be quite rnarked. The s t a n d a r d a l r e a d y r e f e r r e d t o p r o p o s e s an adjustrnent of 1.4 degree dry bulb for each I degree change in rnean radiant ternperature (MRT). The average MRT throughout a space is given approximately by the a v e r a g e t e r n p e r a t u r e ( A S T ) o f t h e e n c l o s i n g r o o r n surface, properly weighted as to.area. MRT will setdorn differ frorn lnean air ternperature by rnore than r 4 degrees F because of the radiation interchange
between various surfaces and with the air itself. But a roorn z0 by 20 by l0 ft with half of one wall of glass ai 32"F and other surfaces and t h e a i r a t 7 2 " F w i l l h a v e a n a v e r a g e M R T approxirnately z l/z d.egrees below roorn air temperature, requiring a cornpensating adjustrnent u p w a r d o f . 1 . 4 x 2 . 5 = 3 . 5 " F i n air ternperature for the sarne cornfort. A sirnilar adjustrnent downward would be required if the same glass or the blind over it in surnrner were at a ternperature of ll0oF.
These and similar radiation effects, including those involving the entry of solar radiation and the presence of heated and cooled
surfaces differing vefy substantially frorn air ternperature, are unfortunately not uniforrn throughout the space as the above average calculations based on AST would indicate. The true MRT, based on the effect on the heat exchange of the hurnan body or of any other object, varies frorn one location to another so that it cannot be fully cornpensated by an adjustrnent in air ternperature throughout the space" This is of
sorne irnportance in considering the effects of windows upon environrnental conditions within roorns.
Air rnovernent, as is well known, has an influence on body h e a t l o s s a n d i s t h e r e f o r e a factor in cornfort. Increasing the air
rnovernent increases convective heat losses and evaporation. Occupants cornplain of drafts when detectable air movelnents are associated with conditions on the cool side. The sarne air rnovernents with conditions on the hot side may not even be detected. Radiant cooling effects resulting frorn proxirnity to cold surfaces are often confused with drafts, but they d o t e n d t o o c c u r t o g e t h e r i n such locations.
T h e s e c o n s i d e r a t i o n s a n d s o r n e o t h e r s , including that of cost, together deterrnine the level of refinernent which it is reasonable to seek in e:stablishing controlled cornfort conditions for occupants.
T e r n p e r a t u r e c o n t r o l t o ! t t/ZdegreesF at the therrnostat represents norrnal practice in design and in equiprnent. This does not rnean, however, that
u - 5
T h e d i s t r i b u t i o n o f h e a t e d o r c o o l e d air, and radiation effects, particularly those arising from windows and the sun, rrray readily cause local variations i n t h e r r n a l c o n d i t i o n s equivalent to air ternperature variations ot ! + degrees F or rnore throughout the occupied zone of a roorn and may be variable
with tirne and location within the rooryl. It is necessary to elirninate these c o r n p l i c a t i n g f a c t o r s w h e n rnore precise control is required., since it is difficult if not irnpossible to cornpensate for thern by rneans of adjustrnent t o a i r c o n d i t i o n s a l o n e .
Cornfort is not rnarkedly af fected by relative hurnidity within the norrnal range bf conditions in occupied buildinqs and so the usual p r a c t i c e o f d e s i q n i n s i y s t e r n s c a p a b l e o f p r o v i d i n z c o n t r o l w i t h i n ; r f a i r l y b r o a d r a n g e o f r 5 p e r cent or even rnore is generally quite
a c c e p t a b l e . A l t h o u g h n o t r e q u i r e d f o r c o n d i t i o n s o f light work and prolonged occupancy it is now cornrnon practice to design for relative humidity as I o w a s 5 0 p e r c e n t i n s u r n r n e r . I t is usually necessary, because of Iirnitations irnposedbythe building to allow relative hurnidities to drop to 2 0 p e r c e n t o r l o w e r , u n d e r w i n t e r conditions. B u i l d i n g s c a n b e d e s i g n e d to carry 35 per cent and even 50 per cent or lrlore under Canadian winter c o n d i t i o n s , b u t t h i s c a n o n l y b e realized if buildings are properly designed f o r t h i s . A r n o r e c o r n p l e t e d i s c u s s i o n o f r e l a t i v e hurnidity and its effects u p o n b u i l d i n g s , o p e r a t i o n s , and rnaterials generaily is provided in
r e f e r e n c e ( 2 ) .
AIR-CONDITIONING FOR MATERIALS AND OPERATIONS
T h e r e a r e a g r e a t r r l a n y p o s s i b l e reasons for the use of air-c o n d i t i o n i n g i n o r d e r t o r e d u air-c e or air-control effeair-cts upon materials,
p r o c e s s e s , a n d o p e r a t i o n s . A i r - c o n d i t i o n i n g r n a y b e r e q u i r e d t o e l i m i n a t e large arnounts of heat in a controlled way frorn interior roorrrs where the ternperature rise occurring with the use of ventilation alone cannot be t o l e r a t e d . C o r n p l e t e l y i n t e r i o r r o o r n s w i l l r e q u i r e cooling but not heating even in winter. Lighting alone to rnodern standards may contributu
"rr""!y at the rate of 5 watts Per square foot. A sirnilar requirernent rnay some-tirnes exist in connection with hurnidity but when temperature control is not involved, ventilation alone rnay be sufficient.
The rnost cornrnon requirernent for precise ternperature control
i n l a b o r a t o r y b u i l d i n s s i s l i k e l y to arise in the case of precision rneasurernents of all kinds. It rnay be desired not only to lirnit changes in length and
v o l u r n e b u t a l s o t o c o n t r o l resistivity, r a t e s o f r e a c t i o n , r a t e s o f g r o w t h a n d a n y o t h e r f a c t o r s a f f e c t e d b y ternperature. I t r n a y a l s o b e n e c e s s a r y t o v a r y t e r n p e r a t u r e i t s e l f as a factor in experiments. E v e n w h e n t h e
I I - 5
control of these in turn if they are located in roorns in which the arnbient ternperature range is redr-lced,
A sornewhat sirnilar general situation rrray exist in respect of relative humidity, where the equilibriurn rnoisture content in rnaterials i s a f a c t o r t o b e r n e a s u r e d o r c o n t r o l l e d , o r w h e r e r a t e s o f e v a p o r a t i o n or rnoisture pick-up are involved. Electronic equiprnent rnay require dry or controlled atrnospheres. Fresh concrete and other hydrating
systerns rnay have to be kept at high hurnidity. Cornputers and business n:achines rnay call for constant relative hurnidity in order to control the dirnensional
changes in paper tape and cards or in filrn. Special conditions rnay be r e g u i r e d f o r s t o r a g e a n d p r e s e r v a t i o n a s w e I I a s i n t h e p r o c e s s i n g o r s t u d y o f a w i d e r a n g e o f r n o i s t u r e - r e s p o n s i v g r n a t e r i a l s s u c h a s p a p e r , leather, plastics, wood, and products derived frorn plants and anirnals generally. Gontrolled conditions rnay be required in rnedical and
biological experirnents when plants and anirnals thernselves are involved.
The temperature and hurnidity control desirable for rnany
s i t u a t i o n s i n r e s e a r c h l a b o r a t o r i e s w i l l o f t e n h a v e t o b e r n u c h r n o r e p r e c i s e than that required for the occupants. It rnay not, in fact, be possible to a c h i e v e b y a i r - c o n d i t i o n i n g a l o n e , a n d i n e x t r e m e c a s e s t h e p r e s e n c e o f occupants as heat and moisture ernitters and as radiators rrlay not be t o l e r a b l e . A s t h e c o n t r o l r e q u i r e d b e c o r n e s i n c r e a s i n g l y r r l o r e p r e c i s e , the kind of system suitable for cornfortair-conditioning will usually be quite incapable of provi.dl,ng the rnore refined conditions. This is r e f l e c t e d d i r e c t l y i n t h e c o s t o f t h e s y s t e m s r e q u i r e d .
EFFECT OF' TEMPERATURE CHANGE ON RELATIVE HUMIDITY It is not always appreciated that relative hurnidity, which is the ratio of the actual water vapour pressure to the saturation pressure, will vary with change in ternperature. Close control of relative hurnidity rneans, therefore, that ternperature rnust also be closely controlled. A ternperature change of I degree F at 75'F will change the relative
hurnidity by I part in 30. To achieve control of relative hurnidity to 50 p e r c e n t ! t / Z a , t 7 5 " , t h e t e r n p e r a t u r e r n u s t b e h e l d w i t h i n t O . : E d e g r e e F . When relative hurnidity control is required at the surface of sorne object in the space, all the therrnal effects, not only air ternperature, rnust be adjusted so that the ternperature of the object is controlled within the perrnissible ternperature tolerance consistent with the control of relative hurnidity required.
I I - 7
VENTILATION, AIR CHANGE, AND AIR DISTRIBUTION
Ventilation is required in the first instance to maintain air
f r e s h n e s s . I t r n a y a l s o b e r e q u i r e d i n s o r n e c a s e s t o c a r r y o f f e x c e s s i v e h e a t o r r n o i s t u r e . F r e s h a i r i s u s u a l l y r e q u i r e d t o t h e e x t e n t o f l 0 c f r n p e r p e r s o n o r o t l / ? t o I a i r c h a n g e i n t h e s p a c e p e r h o u r ( A C H ) , w h i c h -ever is the rnore dernanding. It is cornmon practice, however, to
circulate up to three times this arnount of air, with the fresh air being rnixed with a larger quantity of air drawn frorn the space. Total air changes up to 3 per hour are often desirable to produce adequate circulation and rnixing in the space.
'Vfhen
the air being calculated is also the carrier for heat and rnoisture, the rate of air circulation rnay be governed by the conditions of the entering air. It will be appreciated that if heating and hurnidifying are required via the air stream, the entering air rnust be warmer and rnore rnoist than that in the space under control. Similarly when cooling and dehurnidifying are required the entering air rnust be cooler and drier than that in the space. The arnount by which the entering air condition differs frorn that of the roorn'condition depends on the heat and rnoisture losses or gains of the room and the rate at which air is
circulated. In the case of heating, about 3 ACH are usually sufficient since a ternperature of entering air of frorn 50 to 100'F above roorn ternperature is tolerable. Conditions in this prirnary air strearn are therefore rnarkedly different frorn the desired roorn conditions until it has been thoroughly rnixed with roorn air.
It is the condition of the air exhausted frorn a space rather than that being introduced which closely reflects the roorn air condition. In t h e c a s e o f c o o l i n g , s u c h l a r g e d i f f e r e n c e s b e t w e e n e n t e r i n g a i r a n d roorrl air cannot be tolerated because of the tendency of cooled air to fall, and to produce rnarked ternperature differences in the occupied zone even if it were practical to produce thern. Consequently when c o o l i n g i s a c c o m p l i s h e d t h r o u g h a c o n d i t i o n e d a i r s t r e a r n a s i s u s u a l l y t h e c a s e i t i s n e c e s s a r y t o p r o v i d e f r o r n 8 t o l 2 A C H . I t w i l l b e
appreciated that air distribution, air rnixing, and air circulation becorne very irnportant in order that the entering air strearn be properly
distributed and rnixed with roorn air before it enters the occupied zone where control of conditions rnust be rnaintained. When close control of conditions throughout all of the occupied parts of a roorn are required i t i s n e c e s s a r y e i t h e r t o i n c r e a s e g r e a t l y t h e a i r c i r c u l a t i o n r a t e , o r t o r e d u c e a s f a r a s p o s s i b l e t h e c o r r e s p o n d i n g h e a t a n d r n o i s t u r e l o a d s o n
I I . 8
the room, the object in either case being to reduce the difference
between entering air and room air. Uniforrn air distribution rnay also be prornoted by introducing the conditioned air through perforated
ce iling s .
Principles involved in the design of temperature and humidity c o n d i t i o n e d c a b i n e t s are discussed in reference (3), which provides sorrle further insight into the problerns of achieving uniforrn conditions w h i c h a r e a p p l i c a b l e t o roorns also.
COSTS OF AIR.CONDITIONING
Decisions as to the kind and precision of control of air-conditioning should always be related to costs, since these can vary w i d e l y , i n c r e a s i n g r a p i d l y as the control precision is increased. Such f i g u r e s i n g e n e r a l t e r r n s rnust of necessity be gross estirnates only, since they can be affected by many factors which can vary from case t o c a s e . r t i s u s e f u l t o g i v e them on the basis of floor area where possible so that they may be related roughly to building costs. rt rnay b e a s s u m e d f o r t h e s e comparisons that laboratories cost about $20 per sq ft of floor area, exclusive of heating, ventilating, and air-conditioning.
Heating systerns cost about $4. 50 per sq ft of radiation
i n s t a l l e d . F o r h o t w a t e r h e a t i n g w i t h . a requirement of 50 Btu perhrper f t o f f l o o r a r e a , t h e systern wirl cost $1.50 per sq ft of floor. it,rr.y be noted in passing that hot water is now used alrnost exclusively for heating large buildings.
Air distribution systerns for rnechanical ventilation cost about $1 per cfm of capacity. For 3 AcH the cost will be about 50 cenrs per sq ft of floor area. Air distribution systems for air-conditioning will c o s t a b o u t $I.25 per cfrn and for l0 ACH this arnounts to a little over $ 2 . 0 0 p e r s q f t o f f l o o r .
The cost of central air-conditioning plant will range frorn $+OO to $6oo per ton of capacity. (one ton capacity relates to the heat
a b s o r b e d i n r n e l t i n g I ton of ice per day and equals 2gg,000 Btu pet 7_4 hr or 12p00 Btu per rninute heat removal rate. ) The cost of central plant can be related only very crudely to floor area because of the dependance of cooling load upon location and clirnate, building design and occuPancy' and particularly upon the kind and arnount of tt""" used in exterior walls and the relation between this and floor area. Equating
I I - 9
t h e s e r o u g h l y o n t h e b a s i s o f I t o n p e r 3 5 0 s q f t o f f l o o r , t h e c o s t o f c e n t r a l p l a n t w i l l a d d a b o u t $t. SO per sq ft of floor.
T h e s e f i g u r e s a r e n o t p a r t i c u l a r l y g e n e r o u s a n d r e p r e s e n t ordinary cornfort air-conditioning in office-type buildings, They put t h e c o s t o f a i r - c o n d i t i o n i n g a t a b o u t $ 3 . 5 0 p e r s q f t o f f l o o r , w i t h heating, when this is separately provided, adding about $t. SO for a total of about $5.00. Adding air-conditioning is thus likely to add frorn l0 to 20 per cent to the cost of a building. Costs of owning and operating rnay be in the range of 50 to 75 cents per sq ft of floor for air-conditioning, but again are subject to variations in design, climate, e n e r g y c o s t s , a n d s o o n .
The cost of rnore refined systerns capable of producing closer control of temperature and hurnidity wilt rnount rapidly as perrrissible tolerances are reduced. The total capital cost per ton which is in the r a n g e o r $t000 to $tzoo for ordinary air-conditioning is likely to be d o u b l e d i f c o n d i t i o n s o f , r I d e g r e e and t,t per cent are required, and probably quadrupled if : t/z degree and I r/z per cent are dernanded. Offsetting this, there will be a corresponding reduction in the tonnage required due to the reduction or elimination of glass areas which becornes a l r n o s t e s s e n t i a l w h e n i n c r e a s i n g l y c l o s e c o n t r o l i s r e q u i r e d .
INFLUENCE OF GLASS AREAS
Decisions as to the arnount and kind of windows in exterior walls, together with shading and orientation are without question arnong the rnore irnportant ones to be rnade when designing a laboratory building. The use of substantial glass areas particularly on east and west exposures rnay rnake air-conditioning essential since sutnrner conditions can be intolerable without it.
The rnaxirnurn cooling load associated with the solar transmission through 100 sq ft of ordinary glazing in a west wall is about 4 kilowatts o r j u s t o v e r I t o n o f r e f r i g e r a t i o n . T h e c o r r e s p o n d i n g g a i n a s s o c i a t e d with an equal area of insulated opaque wall is only about 5 per cent of this. Thus the cost for air-conditioning alone under extreme cond.itions, exPressing owning and operating costs as a fixed initial surn together w i t h c a p i t a l c o s t , c a n b e i n e x c e s s o f $zo rot each square foot of glass added on critical exposures ( ) (5). Problerns of glare rnay be introduced with large glass areas requiring either increased levels of artificial
i l - l 0
already discussed, floors or work surfaces heated by entering solar e n e r g y . o r h e a t e d i n t e r i o r e h a d e o r g l a s s s u r f a c e s , i n t r o d u c e serious variations in thermal conditions which are undesirable frorn the point of view of uniform cornfort conditions and become intolerable when precise ternperature or temperature and hurnidity control is to be rnaintained.
Windows, because they usually provide the coldest bounding surfaces of a room under winter conditions, also lirnit the relative hurnidites that rnay be carried in winter if serious condensation is to be avoided (7, 8, 9, l0). A double window with outside wind at -20"F will perrnit no rnore than 30 per cent relative hurnidity without
conden-sation and ternperatures on sash and window frarnes and at the edges of sealed double glazing can be even rnore restrictive, depending on the d e s i g n .
VTINTER RELATIVE HUMIDITIES
Another irnportant question that must be resolved at an early stage in the design of a laboratory is that of the maximum relative hurnidity to be carried in winter. Windows are a lirniting factor as j u s t discussed, but the rest of the enclosure can also be restrictive. The design of exterior walls, particularly when buildings are to be hurnidified in winter has been extensively treated in the Canadian Building Digests of the Division of Building Research and in public B u i l d i n g S c i e n c e S e r n i n a r s ( 2 , I l , l Z , 1 3 , l 4 ) .
PLANNING IMPLICATIONS
The implications of windows and vrinter humidification in relation to building planning in general have already been indicated. Other considerations which follow frorn the previous discussions can be delineated briefly.
Orientation of a building becornes important frorn the point of view or
"offiii-g"in when windows are provided whether or not air-conditioning is provided. An east-west orientation of the long axis of a building minirnizes the extent of east-west glass exposure which is the rnost difficult to deal with.
When rzroderate or high winter hurnidities or precise control of conditions are not required throughout the laboratory building but only in a selected nurnber of rooms, these can with g-reat benefit be
I I - l l
Iocated away from outeide walle. It is preferable also to avoid toP f l o o r l o c a t i o n s i n e x t r e r n e c a s e s . W h e n t h i s p r a c t i c e c a n n o t b e followed, the use of double walls with heating between them in winter rnay be desirable. In a further extension of this, the space between the walls rnay be widened to provide a corridor which is heated but not
hurnidified in winter. This arrangement might also be used to advantage when windows are considered desirable, with ventilation in surpmer used to carry away sotne of the solar heat, provided that a difference in conditions between the corridor and the adjacent inner conditioned space can be tolerated. When air-conditioning is provided, the nurnber of ducts or the nurnber of service pipes or both are incresed, depending on t h e s y s t e r n s u s e d . S p e c i a l c o n s i d e r a t i o n t h e n b e c o r n e s n e c e s s a r y i n planning for these.
Thought rnust always be given to the handling of exhaust frorn furne hoods and any other spaces requiring 100 per cent exhaust to outside. Th" pr-rt"ton of rnake-up air and the balancing of supply and exhaust
quantities throughout the building becorne of particular irnportance. One fume hood exhaust from a laboratory of 300 sq ft can produce ?0 or more air changes per hour. Thus the operation of a large nurnber of furne hoods in a building can represent a relatively very large exhaust which can be a serious problern when the operation of hoods is variable and can lead to a costly load when air-conditioning is provided. It rnay often be desirable to operate fume hoods continuously during working hours, using thern as the building exhaust systern in order to rnaintain balanced supply and exhaust and accepting the high air-conditioning load, provided they can be shut down at all other tirnes.
C o l d r o o m s r n u s t b e c a r e f u l l y c o n s i d e r e d s i n c e t h e y c a n i n d u c e f.reezing in adjacent construction. Frost heaving of basernent floors and frost problems in outside walls can be induced when cold roorns are built in at these locations. Such roorns should preferably be of wood
construction separated frorn the building construction as a rool)n within a roorrr so that air can be circulated, by natural rneans or forced, to avoid freezing. A11 such roorrs for low ternperature work rnust be tightly constructed since air and water vapour leakage can add greatly t o t h e r e f r i g e r a t i n g l o a d a n d c a n c a u s e e x c e s s c o i l f r o s t i n g .
AII hurnid roorns and particularly hot'hurnid rogrns should
always u" tigrttty cott"ttuqted since air atd@rorn them can cause rnoisture problerns in adjacent construction and work spaces.
should never be cornbined with are to be built in as part of the b e a v o i d e d .
CONCLUSION
I I - 1 2
cold roorns if this can be avoided. If they building, outside wall locations should
C o n d . i t i o n e d s p a c e s a r e a g r e a t a i d i f n o t a b s o l u t e l y e s s e n t i a l f o r r n a n y p u r p o s e s i n m o d e r n l a b o r a t o r i e s , T h e t e r n p e r a t u r e a n d hurnidi.ty control required in such cases will often go much beyond that which can be provided by the best of the cornfort air-conditioning
s y s t e 1 T r s .
Cornfort air-conditioning in general laboratories rnay well become the rule as an expected condition of ernployrnent" It is not i n e x p e n s i v e a n d p o s e s p r o b l e r n s w h b n s p e c i a l s i t u a t i o n s a r i s e s u c h a s those involving frtrne hoods" It can, by reducing the fluctuation in a r n b i e n t c o n d i t i o n s , f a c i l i t a t e t h e p r e c i s e c o n t r o l o f b o x e s , c a b i n e t s , a n d o t h e r e n c l o s u r e s . A i r - c o n d i t i o n i n g b e c o r n e s e s s e n t i a l t o a v o i d i n t o l e r a b l y h o t c o n d i t i o n s w h e n l a r g e g l a s s a r e a s a r e u s e d o r w h e n s u b s t a n t i a l h e a t s o u r c e s e x i s t . W i n d o w s , t h o u g h j u s t i f i e d o n t h e g r o u n d s o f s u b j e c t i v e r e a c t r o n o f t h e o c c u p a n t s , a r e i n a l r n o s t a l l c a s e s t e c h n i c a l l y u n d e s i r a b l e a n d add greatly to the arnount and cost of air-conditioning. They cannot be t o l e r a t e d i n l a b o r a t o r i e s i n w h i c h p r e c i s e c o n t r o l o r h i g h h u r n i d i t i e s rnust be rnaintained in roorns adjacent to exterior walls.
S o u n d p r i n c i p l e s i n t h e c o n t r o l o f h e a t , w a t e r v a P o u r , a i r a n d r a i n r n u s t b e e r n p l o y e d i n t h e d e s i g n o f b u i l d i n g s w h e n c o n t r o l l e d h u r n i d i t i e s a b o v e 2 0 p e r c e n t a r e t o b e c a r r i e d w i t h o u t d i f f i c u l t y i n w i n t e r .
R E F E R E N C E S
I , P h y s i o l o g i c a l P r i n c i p l e s , C h a p t e r 8 , G u i d e a n d D a t a B o o k , Fundarnentals and Equiprnent, American Society of Heating,
R e f r i g e r a t i n g a n d A i r - C o n d i t i o n i n g E n g i n e e r s , 1 9 6 3 , p . I 0 5 - 1 2 0 . Z . H u r n i d i t y a n d B u i l d i n g s . N . B . H u t c h e o n . B u i l d i n g M a t e r i a l s N e w s . V o l . 2 0 , A p r i l 1 9 6 4 . ( R e p r i n t a v a i l a b l e - N R - C B I 5 2 ) . 3 . P r i n c i p l e s i n t h e D e s i g n o f C a b i n e t s f o r C o n t r o l l e d E n v i r o n r n e n t s b y K . R . S o l v a s o n a n d N . B " H u t c h e o n . P r o c e e d i n g s I n t e r n a t i o n a l S y r n p o s i u r n o n H u r n i d i t y a n d M o i s t u r e , W a s h i n g t o n , 1 9 6 3 , V o l . Z , C h a p t e r 3 0 , p . Z 4 I - 2 4 8 . ( R e p r i n t a v a i l a b l e - N R C 8 6 0 3 ) '
4 . 5 . 6 . 7 . t I - 1 3 G l a s s W a l l s i n N o r t h A r n e r i c a . N . B . H u t c h e o n , C . I . B . B u l l e t i n , N o . 4 , ' i ' 9 6 3 , p . 1 9 - 2 3 . ( R e p r i n t a v a i l a b l e - N R C 7 9 8 0 ) . S o l a r H e a t G a i n T h r o u g h G l a s s W a l l s . D . G . S t e p h e n s o n . 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 o f B u i l d i n g R e s e a r c h , C a n a d i a n B u i l d i n g D i g e s t 3 9 , O t t a w a , M a r c h I 9 6 3 . P r i n c i p l e s o f S o l a r S h a d i n g . D . G . S t e p h e n s o n . 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 o f B u i l d i n e R e s e a r c h , C a n a d i a n B u i l d i n g D i g e s t 5 9 , O t t a w a , N o v e r n b e r 1 9 6 4 . C o n d e n s a t i o n o n I n s i d e W i n d o w S u r f a c e s . A . G . W i l s o n . 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 o f B u i l d i n g R e s e a r c h , C a n a d i a n B u i l d i n g D i g e s t 4 , O t t a w a , A p r i l I 9 6 0 . F a c t o r y - S e a l e d D o u b l e - G l a z i n g U n i t s . K . R . S o l v a s o n a n d A . G . W i l s o n . 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 o f B u i l d i n g R e s e a r c h , C a n a d i a n B u i l d i n g D i g e s t 4 5 , O t t a w a , O c t o b e r 1 9 5 3 . T h e r m a l P e r f o r r n a n c e o f l d e a l i z e d D o u b l e W i n d o w s , U n v e n t e d . G . C h r i s t e n s e n , W . P . B r o w n a n d A . G . W i l s o n . P r e s e n t e d a t t h e F i r s t A n n u a l M e e t i n g , A r n e r . S o c . H e a t i n g , R e f r i g e r a t i n g a n d A i r - C o n d i t i o n i n g E n g i n e e r s , C l e v e l a n d , 1 9 6 4 . ( R e p r i n t a v a i l a b l e - N R C 8 0 8 5 ) . T h e r r n a l C h a r a c t e r i s t i c s o f D o u b l e W i n d o w s . A . G . W i l s o n a n d W , P . B r o w n . 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 o f B u i l d i n g R e s e a r c h , C a n a d i a n B u i l d i n g D i g e s t 5 8 , O t t a w a , O c t o b e r I 9 6 4 . I I . H u r n i d i f i e d B u i l d i n g s . N . B . H u t c h e o n . 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 o f B u i l d i n g R e s e a r c h , C a n a d i a n B u i l d i n g D i g e s t 4 2 , O t t a w a . J u n e 1 9 6 3 .
