APPROXIMATE DELIVERIES OF WATER METERS. (National Meter Company.)

Capacity of Water Mains.-The table "Pressure Loss in Water Pipes" gives the pressure loss due to frictional resistance, in pounds per square inch, for pipes of different sizes at different rates of discharge and for a length of 100 ft. The table is useful in estimating the size of straight pipe within its range and of a given length to discharge a given quantity of water with a given pressure loss. Thus, let it be desired to find what size of pipe 1,000 ft. long is required to discharge 500 gal. per min. with a pressure loss of about 2 lb. Then, the pressure loss per 100 ft. is 100% X 2.2 lb. Entering the table on the horizontal line marked for 500 gal. and following to the right, a pressure loss of .25 lb. per 100 ft. is found in the vertical column marked for 8" pipe as nearest to 2 lb. pressure loss. Hence, an 8" pipe may be selected.

Kitchen Boilers.-Iron boilers, or hot-water storage tanks, should be galvanized both outside and inside, particularly inside. These boilers are commonly made of mild steel, and are not so durable as the old-time wrought-iron boilers. Many of the poorer grades become pitted very rapidly, and are not to be recommended for first-class work. The

longitudinal seams are either single or double riveted; when double riveted, the rivets should be staggered.

Copper range boilers are in every case to be preferred, if properly coated inside with block tin. They are classed as light, heavy, and extra heavy, the latter being tested to 150 lb. water pressure. The best forms of copper boilers are those which are reenforced inside by stiffeners or braces so that

they will not collapse when a partial vacuum is formed within them.

Ordinary steel or iron boilers are tested to 150 lb. water pressure, and extra heavy ones to 250 lb. pressure. The latter should always be used when the street pressure is more than 40 lb. by the gauge, or when water hammer may at any time come on the plumbing system.

STANDARD SIZES OF GALVANIZED BOILERS.

Capacity. Length. Diameter. Capacity. Length. Diameter. Gallons. Feet. Inches. Gallons.

Feet.

Inches.

The size of boiler which should be employed for any particular work depends chiefly on existing conditions, such, for example, as the water supply and the nature of the building. A safe rule is to allow a 35- or 40-gal. boiler for a building having one bathroom, and to add 30 gal. additional capacity for every extra bathroom.

In practice it is found that about 100 sq. in. of waterback heating surface in actual contact with the fire is sufficient to give good results with a 40-gal. boiler if water is plentiful, and with a 50-gal. boiler if water is scarce.

Boiler Connections.-These are made in different ways; the most common and reliable method is shown at (a) in Fig. 2. The cold-water supply pipe e has a branch ƒ taken off, to

supply the boiler. The return pipe g furnishes a supply to the waterback a, and the sediment cock h is used to empty the boiler when necessary. The hot water enters the boiler through the flow pipe c, and rising to the top, is conveyed to the fixtures through d. The only objection to this arrangement is that it requires a long time for the water in the boiler to become hot, because the hot water continually mixes with the cold. To overcome this trouble, c is often connected to d d

FIG. 2.

over the boiler, as shown in (b). But the latter method is also objectionable, in that circulation between the range and the boiler will cease when the service pipe is shut off, because the hot water will siphon down to the vent hole in the top of the inner tube. The waterback will then blow steam through c and d. To prevent this the pipe c may be connected both to d and to the side tapping of the boiler.

Multiple Waterback Connections.-Two waterbacks may be

connected to the same boiler in the manner illustrated by Fig. 3, the heating capacity of the waterback in the kitchen range a being supplemented by that of a pipe coil in the laundry stove b, so that on washing days the supply of hot

water will be sufficient to meet every demand. The connection between the boiler c and waterback in the range a are made in the usual manner, but the flow pipe d from the laundry stove is connected into the top of the boiler, as shown. The cold-water supply may be shut off by means of