Elevation. Point above the ground surface or top of well casing to which water is raised.

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Total lift. Distance water is elevated from level when pumping to point of discharge, at an elevation, and includes: Elevation + static head + drop total lift.

Lift. Distance the water is elevated from level when pumping to point of discharge at surface, and includes: Static head + drop = lift (pumping head). Submergence. Distance below the pumping head at which the air picks up the water.

100 per cent. The vertical distance the air travels with the water from point introduced to point discharged, and includes: Total lift or lift + submergence 100 per cent.

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CHAPTER XVI

SERVICES

Water service pipe practice has not become standardized to nearly the same extent as wiring or plumbing practice. Safety and sanitation perhaps are not so dependent upon the character of service pipe construction, but health may be affected, and considerations of economy and adequacy of service combine to favor as close adherence to standards as local conditions will allow.

Installation of services, from the main to the curb or property line, by the municipality or water company is becoming increasingly common. Uniformity of construction and economy are among the advantages following the elimination of work by private plumbers in public streets. Much may be said, also, in favor of the owner of the water system installing the pipe through the foundation wall of the building to be connected. Some cities, particularly in New England, follow this practice.

Opinions differ concerning the desirability of installing services at intervals in advance of permanent paving. Circumstances should govern. There can be little question of the desirability of laying connections for all existing houses even though they may not be used immediately, nor for platted lots where building is active. Where land is not subdivided, or where there is small prospect of early building operations, it will be better usually to tear up paving when necessary than to lay pipes that may lie unused for years and perhaps always.

Galvanized wrought iron and steel, unlined or lined with lead, tin or cement; lead, unlined or lined with tin; cast iron; and copper and brass are used for service piping.

Unlined galvanized iron and steel pipe services are commoner than any other kind. They are comparatively cheap and are not easily injured, but some waters and soils cause them to deteriorate rapidly. Active waters attack the metal and are discolored at the tap. Galvanized iron or steel pipes often become clogged to such an extent as to impair service materially. Such pipe is lined with lead, tin or cement to prevent rusting and tuberculation.

Lead pipe has advantages over wrought iron and steel pipe in that it does not rust or decrease in carrying capacity, and it may be curved in the trench. It is easily injured, however, is comparatively high in first cost, and some waters dissolve enough of the lead to cause injury to health. The last named objection is overcome by the use of a tin lining.

Cast iron is a durable material for services. The 1 inch size, comparatively recently placed on the market, provides excess carrying capacity for ordinary residences and incrustation will be of less importance than in the smaller galvanized iron or steel pipe. The first cost of small cast iron services is somewhat greater than that of unlined galvanized services. Some difficulty is experienced due to uneven thickness and to breakage from shock or settlement. The recent development of copper tubing and practicable connecting devices may prove an important advance in service work. This pipe is strong, flexible, not subject to corrosion and incrustation, and of no greater cost than some materials now used.

Services should be laid below the recognized frost line and never so shallow as to be affected by heavy street traffic. In ungraded streets, allowance should be made for future grading operations, in order to avoid the necessity of lowering connections.

Consensus of opinion appears to be against the use of galvanized iron or steel pipe less than 3 inch in diameter owing to the gradual decrease in carrying capacity likely to occur. Lead or copper pipe of smaller size may prove satisfactory for short connections to small houses where pressures are considerable.

Services larger than required for furnishing the necessary quantity of water should be avoided. Architects and plumbers often prescribe too generously in this respect. Large connections increase water waste, raise the maximum demand on the system, and may prove a menace in case of fire. Properly graduated installation and ready-to-serve charges for different sized connections and meters tend to diminish the incentive for such services and repay the water department or company for the facilities granted. The growing prevalence of flushometers, however, increases the demand for large services.

The connection to the water main generally may be at least one size smaller than the service pipe itself. Corporation cocks and goose-necks of inch diameter, for instance, are often used with inch services.

Water mains are tapped for service connections on the top, or at 45° or 90° from the vertical. Tapping in the last-named position is least convenient. The connection is most likely to freeze or be injured if the main is tapped on top. The 45° position proves generally the most favorable.

The brass or bronze corporation cock screwed into the hole tapped in the main is not allowed to project beyond the inner surface of the pipe in some cities, owing to the obstruction caused to the flow of water. In some cases rust or tubercles have been found to have nearly closed the opening in the corporation cock. This condition is avoided in many places by allowing the cock to protrude about inch beyond the inside of the main.

Iron, steel or brass service pipes are generally connected to the corporation cock by a lead goose-neck, which permits change in the relative position of water main and service without liability of breaking the service pipe or connection to the main. The gooseneck is connected to the corporation cock by a wiped joint or a flanged coupling, and junction with the service pipe is made with a bronze nipple or flanged coupling. Where goose-necks are not used, some form of swivel jointed fitting usually provides the required flexibility. Lead services are connected to the corporation cock by a wiped joint or flanged coupling. The use of flanged couplings is growing in favor.

Each service should have a cut-off at the property line. Where there are no meters or they are placed in the building served, a so-called curb cock, furnished with a box so that it may be operated from the surface, is used for shutting off water from the premises. If meters are placed near the property line, the curb cock and curb box are sometimes eliminated satisfactorily through the use of certain types of meter-holding yokes which contain the cut-off valve.

Opinion appears to be mostly against laying water services in trenches for sewers or drains on account of the likelihood of breaking the water pipe when the back-filling in the deeper trench settles. In spite of this, a considerable saving may be made in laying water and sewer connections in the same trench and some water works effect this arrangement wherever possible. In such case, the water service pipe is generally laid on a narrow bench at the side of the ditch or rests on timbers spanning the trench. The saving accruing to the property owner in laying his water and sewer connection

in one trench between the street line and the house should not be forgotten when making a decision as to the desirability of laying the two pipes in the same ditch from the mains to the property line. Meters may be placed in underground settings near the property line or inside the buildings served. The statement is often made that cellar settings are advantageous, due to the smaller chance of having meters frozen. There is much experience, however, to indicate that a meter placed in a properly constructed outside setting is just as safe as one set in the ordinary cellar. Some water works, in fact, have no trouble with the meters they have under ground, but often have meters frozen in cellars where the location is exposed or where houses have been closed without shutting off the water. Outside meter settings should be varied in accordance with local climatic conditions. The large number of frozen meters that have been experienced in outside housings simply indicates that the particular settings provided were improper for the location. If the housing extends below the frost line and is large enough in diameter to allow a sufficient warming effect from the earth below, there will be little trouble from freezing. Single or double lid iron covers are generally provided for the housing. Where severe cold is usual, added precautions are sometimes taken by lining the covers or by filling the space between the two lids with saw-dust or straw. The first cost of setting a residential meter under ground is really the only objection to such an arrangement. Among the advantages are: less danger of damaging the meter by the action of hot water, no chance of making illegitimate connections beyond the meter, no unregistered water lost through leaks in the service pipes on private property, practical elimination of tampering with the meter, and facility and speed in reading under ordinary conditions.

As a general rule, one tap from the water main is made for each property to be served, but there are a number of water works that provide one service as far as the curb or property line for two houses that are near together. From this point, individual pipes pass over the respective private properties to the houses. Separate cutoffs are furnished for each house. Where meters are set near the property line under such conditions, one pipe enters the housing and two meters are set, each on a branch of the entering pipe. A pipe passes from each meter to the respective houses. In cases of this kind, a division of the services should be made before the pipe from the main enters on the private property.