Rural Hygiene

by Henry N. Ogden

Pipe lines.

In bringing the water from the spring or pond to the house, some kind of a pipe line must be provided. Such a pipe line is made of various materials; hollow wooden logs, vitrified tile, cast-iron pipe, wrought-iron pipe, and lead pipe having all been used. The last-named pipe is now too expensive for use in any great lengths. Hollow wooden pipes are employed occasionally, but, except in unusual localities, they also are more expensive than other forms, and are short lived on account of their tendency to decay. Cast-iron pipe, commonly used for municipal water-supplies, is not made in small sizes and may be excluded from the possibilities for an individual house. There remains only tile and wrought-iron pipe. Under certain conditions, the use of tile pipe is to be recommended, since it may be installed even in large sizes at a comparatively low cost, the objection to it being that it is very difficult to make the joints water-tight, and practically impossible when the pressure is greater than ten feet. It is more difficult to make joints in a pipe line of small diameter water-tight than in a pipe line of larger diameter, because the space for the cement in the former is so small. The writer has tried both four-inch and six-inch pipe, and while the four-inch line can be laid with tight joints, it requires much more careful and conscientious effort on the part of the workman than with six-inch pipe. The joints must be thoroughly filled with cement, not very wet, so that it can be rammed or packed with a thin stick into every part of the joint. Merely plastering the cement over the surface of the joint will always result in a leaking joint.

It often happens that a water-supply coming from a distance of a mile or so runs at first nearly level, so that, except for surface pollution, the water might be carried in an open ditch. An open ditch is, however, far better replaced by vitrified tile, six inches in diameter, which entirely prevents surface pollution, and which costs only about ten cents a running foot. When the slope of the ground exceeds the natural fall of the water, so that a pressure inside the pipe is created, iron pipe must be used. If vitrified pipe is used, the joints must be made with the greatest care, and every precaution taken to prevent leakage. Figure 42 shows a section of a joint in tile pipe.

Fig. 42.—A joint in tile pipe.

In using iron pipe large enough to furnish the amount of water required, due regard must be paid to friction in the pipe. In flowing through a pipe of small size, water loses a great deal of head by friction. This friction between the sides of the pipe and the water, which must be duly considered in a pipe of small size, increases very rapidly as the velocity of the flow increases. It is always a great temptation to use a small pipe, since the cost of the pipe increases rapidly as the diameter increases, but it is penny wise and pound foolish to lay a line of pipe several thousand feet long to furnish water to a house and find when completed that the amount of water furnished by the pipe is on account of friction only a small dribble. In a previous chapter we estimated that the flow of water, in order to furnish three faucets at a reasonable rate, ought to be at least two thousand gallons a day or about one and a half gallons a minute, and the effect of a reduced size of pipe on the head necessary to carry a definite amount of water was shown.

The cost of cast-iron pipe should not be more than thirty cents per running foot for four-inch pipe and fifty cents per running foot for six-inch pipe. To this must be added the cost of about seven pounds or ten pounds respectively of lead for each joint and the cost of all the labor involved. The price of terra-cotta pipe is much less, as already indicated, so that it is quite worth while to expend some additional effort on making the tile pipe joints water-tight, if it allows the cheaper pipe to be substituted for the more expensive iron pipe.

Pumping.

Although the present methods of securing water for isolated farm buildings will not corroborate the statement it is safe to say that the proper method of obtaining a water-supply is always to make use of a pond or stream at such an elevation that water will flow to the house by gravity, provided this is possible. Only when the conditions are such that a gravity supply is impossible and water from a well or stream at some lower elevation becomes inevitable is pumping properly resorted to.

The advantage of a gravity supply is twofold. First, the daily charges for maintenance are practically nothing, so that when once the intake and the pipe line have been installed, there will be no additional charges. When pumping is resorted to, on the other hand, there must be a daily expenditure which, even if small, in the course of a year amounts to the interest on a large sum of money. For example, suppose that the cost for supplies for a small pumping engine was only ten cents per day, not counting in the cost of labor. This would amount to $36.50 a year, which at 5 per cent is the interest on $730. It would be $200 cheaper, therefore, to borrow $500, at 5 per cent, to pay for a gravity supply rather than to pay $30 for a pump which costs ten cents a day to run. This same reasoning may be applied to the cost of different kinds of pumps. One pump may cost $200 more than another, but the saving in fuel and repairs may be sufficient to more than justify this additional cost.