June i, 1921 
Some Fundamentals of Stable Ventilation 
345 
out of the stable, these gases—the carbon dioxid and the volatile organic 
products exhaled by the animals—will accumulate and may have inju¬ 
rious effects on them. 
King ( 14 ) bases his estimates of the volume of air which should move 
continuously through stables, first, on the amount of pure air which must 
be breathed by different animals and, second, on the standard of purity 
recommended by him. According to his computations a horse must draw 
into and force out of his lungs, on the average, each hour, some 142 cubic 
feet of air, the cow 117, the pig 46, and the sheep 30 cubic feet. 
The standard recommended by King requires a degree of purity of air 
not lower than 96.7 per cent.—that is, that the air in the stable shall at 
no time contain more than 3.3 per cent of air once breathed. Since the 
air coming from the lungs contains about 4.24 volume per cent of carbon 
dioxid and pure air 0.028 volume per cent, it appears that King’s stand¬ 
ard allows 4.24X0.033 + 0.028X0.967, or 0.167 volume per cent of car¬ 
bon dioxid. From the amounts of air breathed by the different animals 
given above, the rate at which air must enter and leave the stable to 
correspond to this standard is computed per hour and per head as follows: 
For horses: 
For cows: 
For swine: 
For sheep: 
142X100 
3-3 
117X100 
3-3 
46X100 
3-3 
30X100 
3-3 
4,303 cubic feet. 
3,545 cubic feet. 
1,394 cubic feet. 
909 cubic feet. 
It is not claimed that the standard of air purity and the units of air 
movement for the different animals given above are absolutely needed. 
While they probably afford a good gauge by which to be guided, they 
have been given here mainly to illustrate the method and the basis of 
their computation. 
MOTIVE POWER FOR STABLE VENTILATION 
The maintenance of a flow of air through a building requires the con¬ 
tinuous expenditure of energy, and the amount of this energy and the 
work done will be in direct proportion to the weight of air moved through 
the ventilated space and the resistance it is necessary to overcome in 
accomplishing this movement. To supply air to 100 horses, for example, 
at the rate of 4,303 cubic feet per hour and per head, the necessary amount 
of work is that of moving through the stable each hour 4 > 3°3 X+08 x IQQ 
0 & 2,000 
or 17.2 tons, 0.08 representing the weight of 1 cubic foot of air in pounds. 
The power used to accomplish the air movement through stables, as 
already stated, is chiefly the passing wind and the heat and moisture 
given off by the animals. The motive force due to the wind depends on its 
velocity, direction, etc., and is, in general, very variable and sometimes 
