Document jNg9Qp92DmXZDZVe4LYmdaqZO

HEATING VENTILATING AIR CONDITIONING GUIDE 1943 upon the type of disease. In pneumonias22 prescribed conditions should be an effective temperature of 66 to 68 deg, humidity of 50 per cent, air movement of not less than 50 linear feet per minute, oxygen concentration of 50 per cent, and carbon dioxide of less than 1 per cent. Oxygen chambers are more comfortable than oxygen tents. The patients receive unhampered medical and nursing care, and the oxygen concentration, the temperature' and humidity can be adequately con trolled at any desired level. The'chief disadvantages are high initial and operating costs in comparison with oxygen tents, the nasal catheter or face mask method of.oxygen administration. The nasal catheter method is the simplest and most inexpensive.of all but it may cause considerable discomfort to the patient and it is not sa,tisfactory for continuous admin istration' for restless or delirious patients. Moreover, oxygen concen trations greater than 40 per cent in the inspired air are difficult to main tain, although concentrations as high as 48 per cent have been obtained. The face mask is a convenient portable method and permits the admin istration of oxygen concentrations up to 95-100 per cent in the inspired, air. It is economical and convenient and helium-oxygen mixtures may be easily administered. GENERAL HOSPITAL AIR CONDITIONING Complete conditioning of a large hospital involves a capital investment and running expense which may not .be justified. In clean and quiet districts, the requirements of almost all general and private wards during the cool season of the year can be satisfactorily fulfilled by the use of usual heating in conjunction with window air supply and gravity or mechanical exhaust. Insulation against heat and sound is much more important than humidification in winter; it will also help in keeping the building cool in warm weather. Excessive outside noise and dust may require the use of silencers and air filters in the window openings. . Cooling and dehumidification in warm weather are important. In new hospitals particularly, the desirability of cooling certain sections of the building should be given serious consideration. Financial reasons may preclude the cooling of-the entire building, but the needs of the average hospital can be met by the use of built-in room coolers and a few portable units which can be wheeled from ward to ward when needed. In the North and certain sections of the Pacific Coast, cooling is needed but a few days during summer, while in., the South, it can be used to' advantage from May to October, and in tropical climates almost con tinuously throughout the year. Aside from comfort and recuperative power of the patients, cooljng is of great assistance in the treatment of, fevers in the new-born and in post-operative cases, in enteric disorders, fevers, heat stroke, heart failure, and in a variety of other ailments which often accompany summer heat waves. Considerable research is in progress on the influence of air conditioning upon a wide variety of diseases such as pneumonia, upper respiratory diseases, tuberculosis, arthritis, nervous instability, hyper-thyroidism, essential hypertension, skin diseases, and vascular disorders. **The Management of.Pneumonias, by J. G. M. Bullowa, 1937* p. 260. 710 . Chapter 38 TRANSPORTATION AIR CONDITIONING Railway Passenger Car Ventilation, Method of Air Distri- bution. Air Cleaning, Winter and Summer Air Conditioning, Humidity and Temperature Control, Summer Air Con ' ditioriing for Buses and Automobiles THE principles of air conditioning used in connection with stationary applications such as stores, restaurants, hospitals, theaters, and homes are in general applicable to such mobile applications as railway passenger cars, passenger buses, automobiles, and ships. However, the equipment used for these mobile applications, with the possible exception of those on board ship, differs from that used for stationary purposes in that it must meet additional requirements. Especially important are the features of compactness with the retention of ready accessibility for quick inspection and servicing, and low weight. Freedom from vibration which could be transmitted to the supporting vehicle and thus to the passengers is essential.' RAILWAY PASSENGER CAR VENTILATION In non air-conditioned cars, ventilation is accomplished by exhaust fans, roof ventilators, and open doors and windows. This practice provides ah ample supply of outside air but does not prevent the entrance of smoke, cinders, and dirt. An average passenger car contains approximately 5000 cu ft of air and may seat as__many as 80 passengers. The occupants are continually liberating heat, carbon dioxide, moisture, odors, and some organic matter from their breath, skin and clothing. The heat and moisture can be removed by cooling and dehumidification, but the other constituents can be successfully handled only by proper ventilation and air cleansing. In the average car from 2000 to 2500 cfm should be circulated by the air conditioning unit. Some of this air may be recirculated, but a portion of it should always be brought in from the outside. The amount of outside air required depends upon the type of car, number of passengers, air temperature, humidity, odors, and whether or not occupants are smoking, and will vary from 15 to 90 per cent of the total air circulated. Careful attention must be exercised in specifying the rate of outside air taken in so as to fit the type of service adequately and yet not to supply more ventilation than is necessary. Conditioning this outside air is a major factor in determining the size of both summer and winter con ditioning equipment. With present average ventilation requirements, about 30 per cent of the cooling equipment and sometimes as high as 50 711