Plumbing Experiences.—No. 1.
ALL plumbing work in its administrative features is likely to be affected by the public water supply, and according to the extent and measure of the daily pressure exercised upon the general plan of distribution throughout the city. As the age of the water-works increases the fact is developed that the pressure diminishes unless means are provided to compensate for lost pressure. This is seldom done unless it is first publicly demonstrated that pressure is failing and water consumers complain that a necessity exists for something to be done in the way of restoring head.
The cause of course is charged (and justly so) to increase of population in the wwter taking district, A limit is reached in all cases. The aim and purpose of engineers and superintendents in charge of water-works is to preserve all of the head possible to maintain pressures equal to the demand. The plumber in the midst of the experiences just mentioned cuts no small figure in suggesting various plans to overcome the difficulty ; he is very apt to recommend a larger’main service pipe to obtain more water, also a larger tap. At this stage of the trouble it is well to consider why he does not always “get what he goes for.”
When the tap that furnishes the water to the dwelling was driven the pressure at the line of elevation of the water main was, for example, fifty pounds, and an ample supply of water was obtained in all elevations of the dwelling. As time rolls on a gradual diminution of flow, due to diminished pressure, is observed, and where fifty pounds pressure formerly existed, but twenty-five or thirty pounds is all that can be obtained. The plumber feels indignant that he is refused a larger tap and larger service pipe than what was originally furnished. If he would study the result he might with propriety come to the conclusion that if his application were granted for a larger tap and service pipe, it would not give him any greater head of water than he obtained from the small tap and service pipe. It would, however, give him greater volume of flow to the apparatus requiring water, thus saving time, but the water would not rise any higher in the building through the large pipe than it did in the small pipe. If the privilege was granted by the water department authorities it would be of no particular benefit to the water consumer, save only in one respect, that if original pressure were restored by reinforcing the water mains, he, the water consumer, would have acquired, in addition thereto, a benefit just in proportion to the increased cross section of the new tap and increased cross section of the new service pipe over that of the old and first tap and first service pipe used to supply the dwelling.
It is therefore obvious that a departure from the original plan of measured distribution as determined by cross section of area of taps is unwise to say the least. The pressure of course should be maintained consistent with the head required to provide water through certain size taps in sufficient quantity for the purpose desired. This subject will be continued in future issues of FIRE AND WATER.