The New Student's Reference Work/Warming and Ventilation

Warm′ing and Ven′tila′tion are so connected as to be best treated in one article. In one sense they are opposed to each other, as the necessity of ventilation or pure air requires frequent changes of the air, which thus carry off the heated air of a room and require more heat to replace it. The human body must be kept at a temperature of 98° for healthy living, which is secured partly by food, which supplies heat, and by clothing to retain the heat, but largely by artificial heat in houses. Pure air to breathe is also a necessity. The air we breathe contains oxygen and a small part of carbonic acid, which in large quantities is a poison. In breathing, the oxygen is taken from the air and carbonic acid is added to it, so that without a fresh supply the air of a room becomes in a short time so full of carbonic acid as to be poisonous. In warming and lighting a room the same process goes on—the oxygen is taken from the air and carbonic acid gas is given out. A person uses up the oxygen in four cubic feet of air every hour, and makes impure with carbonic acid one cubic foot of air every minute. A large oil-lamp will make impure 70 cubic feet of air an hour; a pound of coal in burning will use up 120 cubic feet of air; and a cubic foot of gas will rob ten feet of air of oxygen. Besides heating the fresh air let into a room for ventilation, the warming apparatus has to overcome the loss of heat through glass windows, walls, floors and ceilings.

The methods of warming and ventilating a room are numerous. The open fire, stoves and furnaces, supplying hot air, hot water or steam, are all in use and all have their advocates. The open fire gives the best ventilation, but is wasteful of coal and unequal in its heat. The close stove is economical of fuel and heats a room quickly, but burns the air, making it too dry for health. The use of furnaces has become quite general, especially for large buildings, as they heat every part of the house and at much less expense than would be necessary to heat the same space with stoves or grates. They burn the air, however, rendering it too dry, and need careful management. In order to prevent the escape of heat double walls, double windows and well-fitting doors are used, but the more successful these contrivances are, the less fresh air enters and the more need of artificial ventilation. If houses were perfectly built, the inmates would suffocate. Two things are necessary in ventilation: to remove foul air and to bring in pure air. As hot air rises, an open chimney in which the air is heated and drawn up, the cold air from the cracks and crevices taking its place, is always a ventilator, and in ordinary rooms, as houses are usually built, a sufficient one. Other methods in use are ventilating shafts, with openings at top or bottom or both, for the removal of the impure air and the introduction of fresh air; the heating of currents of fresh air introduced into stoves or furnaces and then distributed; and in large buildings pumping engines to force fresh air through pipes into all the rooms. The whole subject of warming and ventilation, however, is still a problem to builders. See Heating.