SPRINKLER SYSTEMS - 6
Layout of a Sprinkling System
Layout of a sprinkling system designed so as to place the valves in the house basement. adequate size, but the cost of this operation can be circumvented by putting enough valves in the sprinkling system so that the num- ber of heads going at one time will not be great enough to rob the plumbing. It is very convenient to have all of the valves in a lawn irriga- tion system located at one spot. However, if there are several branch lines which should be separately controlled, putting the valves in one place, for example inside the basement or at the edge of the terrace, requires some extra pipe. If you elect to save pipe and therefore do not locate the valves together, it is advisable to install the valves which control the branch lines so that they can be operated outside of the area «wet by the heads on any particular branch when it is in operation. This arrangement also uses some extra pipe, but the slight additional cost is amply repaid by the convenience of being able to turn the valves on or off without getting wet. Most manufacturers of supplies for lawn irrigation systems have a customer service, the function of which is to advise homeowners on the design of systems. These services will design a system to suit a particular lawn on the basis of a rough sketch of the lawn and other information furnished by you; and they will also check your own plan if you care to submit it. The design of a lawn sprinkling system is essentially a simple matter; nevertheless it is a good idea, once you have drawn your plan, to send it off to the manufacturer whose heads you intend to use and ask for criticism and advice.
Private water supplies
Whether a private water supply system can be used as a source for a lawn sprinkling system depends upon two factors: the type of system and the amount of water available. Systems in which the water flows by gravity to the house in adequate quantity for all the needs of the household and for lawn sprinkling besides can be used if the water is under sufficient pres- sure to operate standard sprinkling heads. Inasmuch as heads are available which will operate under 15 pounds pressure, or even less, pressure is not often a problem if the amount of water is sufficient. If the water must be pumped, there still must be an adequate quantity available; but the limiting factor is often the pump. The usual types of domestic water supply systems which are powered by a small electric motor are designed for intermittent operation and may wear out rapidly if they are run steadily for several hours. On the other hand, some of the larger domestic water systems are not damaged at all by steady running so long as they are given pro- per maintenance. There is no general statement which can be made that will be of much help to you in determining whether a particular water system will stand up under the work that a lawn sprinkling system would put upon it. However information as to whether the system can be operated continuously without damage can usually be obtained from its manufacturer. The capacities in terms of gallons per hour of domestic water systems is freely stated in catalogs and also is sometimes printed on the pump or tank of the system itself. It is an easy matter to compare this capacity with the minimum requirements of the sprinkling system. A round figure for rough estimates is that each head in opera- tion will require 2Yi gallons of water per minute, but in the actual design of systems the more exact figures, supplied by the manufac turer of the heads, should be used.
INSTALLATION PROCEDURES
The first step in actual installation is to mark the positions of the pipe lines and valve boxes with stakes. Any sort of stout stake that will hold a stretched cord is suitable. The stakes should be firmly driven so that they will not be knocked out of place while the digging is going on. Even long pipe runs need only two stakes, one at either end, if the run is straight. After the stakes are driven, a cord may be stretched between each pair and left in place; or it may be stretched and the route of the pipe marked with a streak of garden lime, after which it can be taken down. Stakes which mark the positions of the valve boxes should be set to one side of the line so that they can remain in place while the digging proceeds.
Cutting the turf
One of the good points about underground lawn-irrigation systems is that they can be installed in established lawns without disfiguring the lawn at all. It is necessary only to use reasonable care in cutting and handling the turf, and in re- placing the soil and the turf after the installation is completed. The turf should be cut so that the center line of the pieces will come approximately over the line of pipe. Cut in this way the turf, when it is replaced, will form a sort of tough blanket or membrane over the area of soil which was disturbed the most and will tend to conceal it. If the installation is going to be carried out within a day or two, the cut turfs can be stacked alongside the cut. However, if the installation will take longer than two days, it is best to pile them elsewhere to avoid damage to the adjacent grass. If the turfs do not have to be removed from the lawn, they can be cut rather thick and each turf placed beside the area from which it was removed. If this procedure is followed, the turfs can be handled so that when replaced they will re-establish themselves and continue growing practically without interruption. Another advantage is that the turfs need not be cut to a uniform size since each will go back into the hole from which it was removed. However, if the turfs cannot be handled this wav, they should be cut uniformly so that each can be put back anywhere along the line without special fitting. Pieces of turf are removed by cutting all around the border with a sharp, narrow spade, then inserting the spade underneath the turf and cutting it loose. Turfs which are not to be moved far can be cut 4 or 5 in. thick; 2 to 3 in. is a better thickness for those which must be moved a distance. Once it is cut loose, a fairly large turf, up to about 15 in. square, can easily be lifted with an ordinary spade.
|
