First stage hygiene / [Robert Arthur Lyster].

  • Lyster, Robert A. (Robert Arthur)
Date:
1914
Catalogue details

Licence: In copyright

Credit: First stage hygiene / [Robert Arthur Lyster]. Source: Wellcome Collection.

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    of ozone—gradually oxidises and renders harmless the organic impurities. As the result of all these purifying agents the composi- tion of ordinary air remains constant. Amount of air required per head. We have seen that (1) an average adult produces ‘6 cubic foot of carbon dioxide per hour by respiration, and (2) the amount in the air may be increased by -02 per cent, without produciug any injurious results. From (2) we may say that— ■02 cubic foot of carbon dioxide may be added to 100 cubic feet of pure air, .'. ‘2 cubic foot of carbon dioxide may be added to 1,000 cubic feet of pure air, .•. '6 cubic foot of carbon dioxide may be added to 3,000 cubic feet of pure air, i.e. an average adult produces sufficient carbon dioxide to render impure 3,000 cubic feet of pure air in one hour. Therefore 3,000 cubic feet of fresh air must be supplied for each person in a room. It is found that the air in a room can be changed three times per hour without causing any draught, and so if 1,000 cubic feet of space is provided for each person, and we change the air three times per hour by proper ventilation, the necessary 3,000 cubic feet of fresh air is supplied. For example, suppose it is desirable to know how many people may be allowed to sleep in a room 12 feet long, 8 feet broad, and 10 feet high : here the cubic contents are 12 x 8 x 10, i.e. 960 cubic feet. Evidently from the above, only one person should sleep in such a room unless special methods of ventilation were adopted so as to change the air more than three times per hour. In calculating the contents of a room more than 12 feet high it is best to reckon 12 feet only for the height, because cubic space is of no value when it is principally obtained by means of lofty ceilings. For sick people the supply of fresh air should be at least half as much more than that allowed in health, i.e. 4,500 cubic feet per hour. Soldiers in barracks are allowed 600 cubic feet of space; children in board schools 100 cubic
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