The Kinds of Ventilation
There are primarily two kinds of ventilation forced and natural.
Forced ventilation is only necessary in office buildings, factories, theaters and such places where an artificial suction is the only means by which the impure air can be removed. This system for dairy barns would not only be expensive, butunnecessary.
The theory as worked out by Professor King, formerly of the University of Wisconsin, is the basis today, either in its original
form, or with such modifications as later experiments have proven advisable, for all natural ventilation systems.
We have dwelt at length on the subject of why to ventilate, without entering into a technical explanation or submitting statistics.
As applied to a dairy herd it is merely a matter of dollars and cents. The less pure air given to the animal, the more water and feed required. To properly fatten cattle or to keep them in a healthful condition without an adequate supply of pureair is next to impossible. Proper food, plenty of water and, above all, adequate ventilation, are the essentials which keepthe production of the dairy herd at its maximum.
The Real Problem of Ventilation
The real problem of ventilation is not WHY to ventilate, but HOW to ventilate.
The intake and outtake flues as well as the cupola itself, must have sufficient capacity. The ideal arrangement is to have
the fresh air released in front of the cattle and the foul air taken out near the floor back of the cattle.
While it is true that warm air rises, and as warm air is exhaled, one might get the impression that the impure air would be
near the ceiling. The fact is that respired air cooled to a temperature between 70 and 30 degrees is heavier than pure air of the same temperature. This, together with the fact that the foul air and gases rise from the gutters, will explain the reason for having the outtakes extend almost to the floor.
This system permits the fresh, pure air which is released in front of the cows and at the ceiling, to become moderated
before reaching them, and at the same time there is a tendency to constantly force the foul air back of the cattle.
To obtain the best results, both intakes and outtakes should be double thickness insulated with paper between, making an airtight construction. All hay chutes should be kept closed so that the air both coming in and leaving the barn will follow
the channels intended.
On the pages which follow, we have illustrated and described at length ventilation systems for the various conditions to be met.
While the foul air outtakes are important they are no more important than the cupola into which the foul air flows.
STAR Steel Cupolas were designed with a knowledge of the conditions to be met. The wind blowing through the opening creates a suction or up-draught. This design prevents a down-draught which would defeat the object for which the entire system was designed.