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1948-49 Theatre Catalog, 7th Edition, Page 452 (439)

1948-49 Theatre Catalog, 7th Edition
1948-49 Theatre Catalog
1948-49 Theatre Catalog, 7th Edition, Page 452
Page 452

1948-49 Theatre Catalog, 7th Edition, Page 452

lioor an extensive electric substation full of switches, motor-generator sets and the like. I helped abolish that onee S.R.L.

J.A.E. philosophizes about the ethics of the situation and architects before attacking the problem.

The question from fiT.L.ii in the July issue on return air intake location in a theatre interests me for two reasons: the first is because of what might be termed the ethics of the situation, and the second is the technical problem involved.

Question of Ethics

Regardless of the problem involved, I agree heartily with "TL." in that he has refused to prepare a design on a basis dictated by others, when he believes such a design is faulty. Consultants daily are confronted with this same problem, usually forced on them by the desire of architects to avoid changing their designs, failure of architects to understand the art of air distribution, failure to provide sufiicient space for equipment, and because of the client's natural desire to cut costs.

I do not mean that the architect should be required to change his basic design at the whim of the mechanical consultant. Usually, a little cooperation is all that is required. One of my most pleasant associations is with a well known firm of architects, which calls me in during the preliminary stages of a project. By both of us realizing the problems of the other, we have been able to serve the ultimate client to far better advantage than if one of us had been dogmatic in refusing to see the requirements of the other.

I appreciate the normal desire of the client and the architect to keep the cost of mechanical equipment as low as possible. However, it is not appropriate to construct a fine building, regardless of cost, and then limit the mechanical equipment to a point that it performs its function maybe 50 per cent of the time. It is easy to design an air conditioning system that will perform at guarantee under maximum design conditions. How 'ever, it is another story to make that

same system do the work under intermediate conditions. The architect should properly leave this to his consultant, or if he does not have proper confidence in the consultant, he should get another one.

Obiec'l' to Air Currents on Back

In regard to the problem of HT.L.ii, based on the size of the theatre, it appears to have capacity of about .1200 seats. In other words, this does not appear to be a Hneighborhood theaterfi but possibly a first run house. If so, I believe a little refinement over the small JOb would be in order.

I My experience with theatre work has Indicated that most patrons will object to air currents on the back of the head and neck, as would probably be obtained with all of the return air intakes at the screen. Hovvover, for heating work, it would be desirable to return part of the air at the screen. On the other hand, Unless this job is located in a cold cli I 948-49 TH EATRE CATALOG

mate, the heating requirement is probably small, particularly if the house can be pre-heated before the show starts.

Personally, I do not like side wall outlets in a theatre, preferring overhead distribution. Generally the cost of the distribution system is lower, and certainly it is more effective. With this type of distribution, and with the sloping floor, it appears that mushrooms in the fioor, or other type of fioor returns, would be a simple solution. Low side wall returns might be the answer. At any rate, I would recommend that part of the return air be taken at the screen, or near the front of the house.

For reasons of economical operation, I would suggest that the equipment be arranged to handle all outside air for the intermediate seasons when outside conditions would be satisfactory under light loads. This certainly would require a separate return air fan, arranged for returning the air to the equipment, or exhausting 100 per cent.*J.A.E.

On the basis of his experience, E. G. submits another solution of the original problem. The three following discussions are from the September HPAC.

To accomplish efiicient air distribution in a theatre air conditioning job, it is essential to obtain temperature equalization in the occupied zone and to prevent infiltration of non-conditioned outside air.

Even though the air supply outlets may be well selected and installed, proper air distribution is difficult to obtain in the area near the screen, where in filtration is most likely to originate from the space behind and above the stage. In this section the level of the occum pied zone drops considerably below that of the rear of the theatre-17 ft. in the present case. By locating return intakes in the rear of the theatre (Fig. 1), the neutral pressure zone is raised to such an extent that non-conditioned air will enter near the stage and cause an excessive temperature variation between front and rear of the space. If such infiltration is minimized by solid construction of stage and stage loft, air stagnation will result and cause discomfort due to uneven room temperatures and stuffiness. This applies to operation of the heating as well as the cooling cycle. Further aggravation of this condition would be caused by operating exhaust ventilation with intakes in or near the ceiling during periods of occupancy. (Obviously such ventilation would be advantageous and desirable before and after shows to remove vitiated air.) By installing return intakes at the lowest possible levelenear the screen (Fig. 2), infiltrated air is removed at its source. The neutral pressure zone is lowered sufficiently to keep infiltration at a minimum and air stagnation is avoided throughout the entire occupied zone.

The company I am associated with has had considerable experience with air distribution problems as applied to theae tres, and as a result we have come to the conclusion to insist on extracting a large portion or the entire amount of return air through intakes located near



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1948-49 Theatre Catalog, 7th Edition, Page 452