Conservation by sanitation ; air and water supply, disposal of waste, including a laboratory guide for sanitary engineers.

  • Richards, Ellen H. (Ellen Henrietta), 1842-1911.
Date:
1911
Catalogue details

Licence: Public Domain Mark

Credit: Conservation by sanitation ; air and water supply, disposal of waste, including a laboratory guide for sanitary engineers. Source: Wellcome Collection.

Provider: This material has been provided by the Harvey Cushing/John Hay Whitney Medical Library at Yale University, through the Medical Heritage Library. The original may be consulted at the Harvey Cushing/John Hay Whitney Medical Library at Yale University.

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    told that one must not open the windows is to condemn any system. Again, when indoors, the least feeling of moving air means catching cold, and the velocity required to change the air rapidly enough for a large number of persons in a limited space is intolerable to a majority of those who enjoy ten times the breeze in an automobile. The engineer has to reckon with these psychic obsessions as very real obstacles to his work. The ideal modern system of mechanical ventilation is a com- bination of push and pull. A plenum inlet and an exhaust fan to the outlet. This obviates the high velocity at inlet which is essential if all the power for the movement of the air is located at that point. By a combination of natural up-draft aided by mechanical suction instead of using force developed by heat, the exhaust fan is installed, for lavatories, laboratories, and many factories with noxious gases. In a building used by many persons for many purposes coming and going, the regulation of the currents of air so that they shall go in the desired direction and not in the opposite, requires the constant attention of an intelligent and informed janitor. With any aided natural system, the window leakage may reach 30 per cent. Tests of air leakage around windows were reported by Mr. H. W. Whitten at the recent meeting of the American Society of Heating and Ventilating Engineers. He has found that with a wind pressure equal to 0.1 inch of water outside a window having a sV-inch clearance between window frame and sash, 105 cubic feet of air were driven per hour through each lineal foot of such clearance space, while with a xV-inch clearance the leakage was 184.8 c.ubic feet per hour. With other windows, equipped with good metal weather strips and subjected to the same pressure, the leakage amounted to no more than 12 cubic feet per lineal foot per hour. In tests made with a pressure of \ inch of water, which corresponds to a wind velocity of 24 miles per hour, leakages were noted of 19 cubic feet for ^V-inch clearance, 402 cubic feet for xV-in. clearance, and 45.6 cubic feet for the sash with the weather strips. With a