It is not the purpose of this work to take up the consideration of either hot- or cold-water supply in a comprehensive manner. There are certain things, however, which many of the readers of this book will desire to know, and some of these will be briefly given at this point.

The range boiler, to be in keeping with the other plumbing fixtures of such work as shown in Plate 34, should be of copper. The galvanized boiler has a great advantage in first cost, but the copper boiler will generally outlast several of the galvanized. On contract work the 30-gallon boiler is much used, but 40 gallons is a better size for apartment buildings having individual range boilers.

Plate XXXIV. Plumbing For Apartment Building-Systems Of Hot-Water Supply-Range Boilers, Etc

Plumbing for

Apartment Buiding Plate 34

For residence work, boilers of larger capacity than 40 gallons are often required. For large apartment buildings, office buildings, etc., it is far more satisfactory and more economical to provide a large tank heated by a special heater. This practice does away with the use of a boiler for each apartment.

A method often followed in the use of the large hot-water tank or boiler, is to provide it with steam coils connected to the heating system, by means of which it may be heated in the winter time, a small heater providing heat for it during the summer time. One of the annoyances in this work comes from carelessness or inattention to the heater on the part of the attendant. This may be avoided by the use of automatic tank regulators, of which there are several makes on the market. By means of such an appliance, the temperature of the boiler heated either by steam coils or coal-burning heater, or by both, may be regulated to a certain temperature.

The size of main necessary to supply the plumbing fixtures for a large apartment building, office building, or other similar building, is a problem that is often difficult to solve. The main and branches, if properly sized, will allow water to be drawn at any fixture or any reasonable number of fixtures, without affecting the free flow of water at other fixtures. When pipes of too small size are used, however, the use of water at a single fixture will result in a reduced flow at other fixtures. The following will be of service in estimating the necessary size of main to perform given amounts of work. In the first place, it must be remembered that all fixtures are not in use at any one time. The chances are that in an apartment such as shown in Plate 34, not more than one fixture in the bath room will be used at any one time, or more than one fixture in the kitchen. Therefore, in the case of apartment buildings, the main will be ample in size if designed to supply two1/2-in. fixture supplies per apartment. Thus, if there were 20 apartments, a main having a supplying capacity equal to 40 1/2-in. pipes would be of sufficient size. The following table shows the approximate number of 1/2-in. pipes different larger sizes of pipes will supply:

Referring to this table, it will be seen that a size between 2 in. and 2 1/2 in. will be required to supply this system. The 2 1/2 in. would be the safer and better size, although 2 in. would no doubt do the work satisfactorily. In a great many systems this question could not be figured out in this way. For instance, in large toilet rooms of hotels, railroad stations, etc., the demand at times is large and at other times small. The main supply lines and branch mains under such conditions must be made to supply maximum requirements.

In supplying hot and cold water to apartment buildings and other similar work, each group of fixtures should be supplied by a separate line. Thus, each kitchen should have its own supply, and each bath room also, each line having a shut-off. This avoids much annoyance, for if otherwise, the making of repairs in one flat might result in the shutting off of the supply in others. On a great deal of high-grade work, faucets for the various fixtures are specified to be of the Fuller pattern, and on public work often of some self-closing pattern. Both Fuller and self-closing work closes very quickly, and water, being almost incompressible, forms a very poor cushion to receive the shock. The common result in the use of these two styles of work is a snapping and jarring of the pipes whenever the faucets are closed. Air chambers properly placed will often entirely remedy this trouble. Compression faucets, however, are much slower in closing, and from them none of the above annoyances is experienced. Compression work is not only better many times than Fuller and self-closing work, but it is less expensive.

Two systems of supply are in general use: tank pressure and street pressure. In the use of range boilers on the direct or street-pressure system, supplies are taken directly to the boilers, while in the use of the tank system the supply for the boilers is taken direct to the tank and from that point delivered to the boilers below. The result of the tank method of supply is a uniform pressure, while the direct system gives a pressure which varies greatly according to the demands that are being made upon it. Boilers used on tank systems may usually be of lighter construction than tank boilers, although this is not true in the case of high buildings. The conditions in very high buildings are of a special nature, often requiring special apparatus. For instance, many office buildings, hotels, etc., in the large cities, are of such great height that the pressure on the street mains is not sufficient to force water to the upper floors. Under such circumstances, for those floors not reached by direct pressure, a house tank above all fixtures must be provided, into which water must be pumped.

Large hot-water boilers are generally of the horizontal pattern, hung from the cellar timbers by heavy wrought-iron hangers.

The following is a table of boilers of standard size and make, and their capacities:

For apartment buildings such as shown in Figs. 34 and 35, the construction of circulation work is of very great advantage, as it is in almost any system of plumbing. On ordinary work, the hot-water supply is run from the hot-water main, and ends at the fixture which it supplies. In circulation work, the supply is run from the main also, but it is returned by a circulating or return pipe, into the boiler. The result is that in the first case a long line of pipe filled with cold water must often have to be drawn off before the water will run hot, while in the use of the circulating pipe, the water will run hot almost at once. The latter naturally causes much less annoyance to the person desiring to draw hot water. The first cost of circulation work is greater than that of ordinary work, but if the water is metered and paid for by the cubic foot, it will be found that circulation work generally figures out a good investment.

In installing hot- and cold-water supply systems for large buildings, it is usual to supply headers which are connected with the boiler. Separate headers are used for the cold supply, hot supply and return. The street supply is connected with the cold-water header, and from it all cold-water supply lines are taken out. The flow pipe from the boiler is connected into the hot-water header, and from the header all hot-water supplies are taken off. All return or circulation pipes are connected to the return header, and the latter connected to the boiler return. Each line of pipe connecting with each header should be provided with a stop and waste cock close to the header, a small waste connection from each cock being connected into a main line of waste, which should empty into some convenient basement fixture. Such a waste should not be connected directly into the drainage system. Each line of hot- and cold-water supply, and each return pipe should be provided with a metal tag, showing what fixture, or group of fixtures, and what floor it serves.

A keyboard, as the above arrangement is called, is a very convenient thing, especially on large work, and is much used in nice residences, apartment buildings, office buildings, etc.

In the event of bursts or other emergencies, the keyboard shows at once the valves that control the piping that is to be shut off, and often saves damage to the property that would result if the proper valve could not be found quickly. The use of the valve waste allows the contents of the pipe to drain off into the fixture without discharging onto the cellar bottom.

The foregoing, as already stated, is not meant as comprehensive in any way, but is given simply in a suggestive manner, in connection with the general subject of drainage of different classes of buildings.