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1945 Theatre Catalog, 4th Edition, Page 396 (372)

1945 Theatre Catalog, 4th Edition
1945 Theatre Catalog
1945 Theatre Catalog, 4th Edition, Page 396
Page 396

1945 Theatre Catalog, 4th Edition, Page 396

Drafts Will Hurt the Box-Office Receipts

The Cause of Drafts and Their Elimination Through .Use of Air Diffusers ls Explained

The difference between success and failure of a theatre air-conditioning system may not be caused by some complex mechanism or action of mysterious origin back in the refrigeration equipment. More likely it will be due to the lack of a simple piece of the right equipment at the duct outlets of the system.

True, a good compressor, fan, and coil do have an important bearing upon the final results, but they alone do not assure successful air conditioning. Even though the air be filtered, cooled, and piped to the outlets in the orthodox mane her, the system may be a failure if the air is then thrown or dumped upon theatre patrons as though the process were finishedewhen, in fact, it has only begun.


The definition of a draft should be given at the outset. It is a term loosely used, a variable with the individual, his condition of health, and the season. A draft is caused by unequal exposure of parts of the body to an air motion which localizes body sensations to ones back or feet rather than to the body as a whole. More heat is then removed from some sensitive part of the body than that part normally dissipates. If that does not register on ones conscious mind as a feeling of discomfort, it will register the next day as a stiff neck or a sore throat. Of course, some, slight degree of turbulence of air must be present in any system where proper air circulation is maintained.

GENERAL VIEW of the auditorium, toward the stage, of the Hollywood Theatre, Sioux Falls, South Dakota, shows ceiling Anemostats, which provide draftless distribution of conditioned air through the whole orchestra area. Note also the effective utilization of the stage draperies, and slde-walI-trough lighting.


Before air distribution became a precise art, the design of registers or grilles on duct outlets was based solely upon appearance and the size necessary to pass the volume of air required for heating. Drafts were not so readily produced by air-heating equipment, since the heated air fioats upward. With the introduction of theatre cooling, however, the heavier, cooled air tended to fall upon the audience so quickly that mixing or dilution with the Warm air of the theatre took place around the patrons, instead of in the ceiling area above them.

In order to prevent this cold air from coming in contact with the patrons, airconditioning engineers tried introducing only slightly cooled air in greater volumes. But the necessary increased volumes of slightly cooled air created more drafts due to the more rapid air movement. In addition, the greater volumes of slightly cooled air required larger equipment and resulted in higher operating costs. So one got back to where he started. It was all a vicious circle.

It was soon recognized that with ordinary registers or grilles on duct outlets, no system of theatre air-conditioning could avoid being drafty. Regardless of whether slightly cooled air or very cold air was introduced into the theatre, you always had drafts with these outlets. Except for the discomfort of drafts, however, the introduction of very cold air had one decided advantage. A given


amount of very cold air took up more heat from the theatre air than an equal amount of slightly cooled air. Hence, much smaller volumes of very cold air were required and equipment and operating costs were lower.


Research and experience in air distribution has shown that all that is required to eliminate drafts from air-conditioning systems, using either slightly cooled or very cold air, is the use on duct outlets of an air diffuser which pre-mixes the supply air with the theatre air entirely above the audience zone. In other words, an air-diffuser which pro-mixes the supply air and the theatre air within the diffuser itself.

Such a device equalizes the temperature and humidity of the air mixture by thorough diffusion of the air mixture within a short distance from the outlet, away up above the audience. All of the advantages of very cold incoming air can be obtained with such an air diffuser -smaller volumes of supply air, lower operating costs, and less expensive equipment.

First attempts to design a ceiling airdiffuser culminated in the pan-type outlet. This was nothing more than a hole cut in the ceiling with a simple pan or plaque below it to hide the hole. The pan also acted as a crude and temporary block to cold air currents which usually dropped immediately to the floor below.

The performance of this type of outlet is affected by the ceiling construction and

SINCE THE WIDTH of the Luna Theatre, Chicago, is relatively small, wall-type Anemostat air diffusers were sufficient to complete air distribution without drafts. These diffusers replaced the conventional type grilles when patronage began to fall off due to drafts obtained during the season of air cooling.

1945 Theatre Catalog, 4th Edition, Page 396