Amount of Air-space required.—We may take 3,000 cubic feet of air as the average amount of air required hourly by each individual, and inasmuch as the air of a room cannot be changed oftener than three times an hour without producing an unpleasant draught, it follows that at least 1,000 cubic feet of space must be allowed per person.
This may be compared with the amount actually supplied under various circumstances.
| In the British Army for each soldier— | |||
| In permanent barracks | 600 | cubic ft. | |
| In wooden huts | 400 | „ | |
| In hospital wards at home | 1,200 | „ | |
| In hospital wards in the tropics | 1,500 | „ | |
| In general hospitals | 1,000-1,500 | „ | |
| In fever hospitals | 2,000-3,000 | „ | |
| In workhouse hospitals | 850-1,200 | „ | |
| In common lodging houses | 300 or 350 | „ | |
| Do., if occupied night and day | 350 or 400 | „ | |
| In workhouses | 300 | „ | |
| In schools— | |||
| London School Board requires per scholar | 130 | „ | |
| English Educational Code per scholar (minimum), in old schools | 80 | „ | |
| Do., in new schools | 120 | „ | |
Floor-space has an important bearing on ventilation. In calculating the available cubic space of a room, the height over 12 feet should be disregarded. Thus, if 500 cubic feet is allowed for each individual, the floor-space should be 42 square feet. In barracks, soldiers are allowed 50 square feet of floor-space.
In the Government regulations for workhouses it is stated that there must not be more than two rows of beds, and that the height of rooms above 12 feet must not be reckoned. This gives a minimum floor-space of 25 square feet per occupant, or with dormitories 17 feet wide, a bed-space of about 3 feet.
In hospitals, the question of floor-space is extremely important, as it regulates the distance between the sick inmates and the convenience of nursing. Assuming each bed to be 3 feet wide and 6½ feet long, the distance between any two beds should be at least 5 feet. This makes the wall-space for each bed 8 feet long, and allows from 80 to 96 square feet of floor-space per bed. At St. Thomas’s Hospital, London, the floor-space is 112 square feet, and in fever hospitals it is from 150 to 300 square feet per bed. In regard to the ventilation of hospitals, it has been well said that nothing less than too much is enough.
Means of ascertaining Cubic Space.—Circumference of a circle = Diameter (D) × 3.1416.
- Area of circle = D2 × .7854.
- Area of square = square of one of its sides.
- Area of rectangle = product of two adjacent sides.
- Area of triangle = base × ½ height, or height × ½ base.
- Area of ellipse = product of the two diameters × ·7854.
- Circumference of ellipse = half the sum of the two diameters × 3·1416.
- Area of any polygon found by dividing into triangles, and taking the sum of their areas.
- Cubic capacity of a cube found by multiplying the three dimensions together.
- Cubic capacity of a cylinder = area of base × height.
- Cubic capacity of a cone or pyramid = area of base × 1 ∕ 3 height.
- Cubic capacity of a dome = area of base (circle) x 2 ∕ 3 height.
- Cubic capacity of a sphere = D3 x ·5236.
- Area of segment of a circle found by adding to ⅔ of product of chord and height, the cube of the height divided by twice the chord.
(Ch x H x ⅔) + H3 ∕ (2 Ch)
Give the dimensions of a circular ward for 12 patients, each to have 1,750 cubic feet of available air-space.