Abstract
It is only comparatively recently that the realization of the desirability of a supply of pure air in buildings has been put into practice. In the early attempts to improve the air conditions in buildings it was thought that the mere admission of external air in sufficient quantity might suffice, but that was soon found to be inadequate. The ideal condition of the air suggested by the author is a temperature of 60 deg. F., a relative humidity of 50 per cent, and not more than 6 or 7 parts per 10,000 by volume of carbon dioxide. The air treated should also have dust, fog, and deleterious gases removed.
The author describes mechanical means for air conditioning and indicates the method of calculating the amount of conditioned air required in any given case. Examples of some typical installations are also illustrated. Filters for the removal of dust are of special importance in certain industries. Dry filters are very effective, but are expensive. In most cases the use of a viscous filter suffices.
The paper concludes with descriptions of various types of instruments for measuring humidity, a special type of centrifugal refrigerator for cooling the air delivered into buildings which uses dichloromethane as a refrigerant, and apparatus for ozonizing the air supply.
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