Natural and artificial methods of ventilation.

Date:
1899
Catalogue details

Licence: Public Domain Mark

Credit: Natural and artificial methods of ventilation. Source: Wellcome Collection.

    17/96 (page 9)
    The Builder (April 30th, 1898), referring to a mechanical system of ventilation, says ;—“ Mr. . . c lays it down as an axiom that the rate of air motion through the air inlets into the room should not be more than 5 feet per second. This is, in our opinion and in that of good authorities, too much; and 2 feet per second is far preferable.” How a Natural System of Ventilation Acts. As the warm air expands it ascends^ ... as the warm air ascends the air around rushes in to fill its placel'—Sir Douglas Galton, F.R.S. A scientifically arranged natural system of venti- lation utilises the never-ceasing movement or natural force which exists in the atmosphere as an unfailing motive power, in conjunction with the difference in temperature of the internal and external atmosphere. As applied to buildings, it consists of specially constructed updraught ventilators which remove the pressure of the external air from the top of the outlet shafts and create, under all conditions of the weather, a continuous and powerful exhaust at the higher parts of the building; combined with properly arranged air-inlets, fixed at the lower levels, admitting the air directly through the walls in an upward direction at a low velocity, purified, and warmed or cooled as required, ensuring a constant change of air and perfect diffusion of the fresh air supply in accordance with the natural laws which govern ventilation. The higher temperature in an occupied building B