An irrigation system require a careful selection of pipe diameters because the diameter of the pipe determine how water move through the irrigation system. If you select a pipe diameter that is too small, the water will struggle to move through the small pipe, and the small pipe will cause a loss of water pressures. If you select a pipe diameter that is too large, you will spend more money on materials then is necesary for the irrigation system.
Therefore, you must understand how pipe diameter, distance, and flow rate interact so that you can create an efficient irrigation system. An irrigation system is organized into a hierarchy that include a mainline and laterals. The mainline is the largest pipe in the irrigation system, and the mainline must be large enough to carry the total volume of water require by every zone in the irrigation system.
How to Choose Pipe Size and Parts for Irrigation
The laterals is smaller pipes that branch off from the mainline, and the laterals deliver the water from the mainline to the soil. If you attempt to run the entire volume of water through a narrow mainline, the water velocity will increase too much and high water velocity can cause water hammer. Water hammer create shockwaves within the pipes, and water hammer can crack fittings or blow out joint in the irrigation system.
Water velocity is a critical factor in irrigation design because high water velocity cause friction. Friction occurs when water move through a pipe, and friction causes a loss of water pressure. If the water pressure becomes too low because of friction, the emitter in the irrigation system wont have enough pressure to spray or drip water.
Larger pipes allow for higher volumes of water to move with less friction, but larger pipes also cost more money than smaller pipe. You must balance the upfront cost of larger pipes with the long-term efficiency of the water delivery in the irrigation system. The material you choose for the irrigation system is also important because different materials serve different purposes.
PVC is a rigid material that provide UV protection, and people often use PVC for buried mainlines in an irrigation system. HDPE is a flexible material that can handle changes in temperature, and people often use HDPE for long run in an irrigation system. You must choose the correct material for you environment because choosing the wrong material can lead to leaks in the irrigation system.
Small hardware component are also necessary for the function of an irrigation system. You must use a pressure regulator if you are using a drip irrigation system, because a pressure regulator prevent the high pressure from popping the emitters off the pipe. You must also use a filter in the irrigation system because a filter prevents sediment from enter the pipes.
If sediment enters the pipes, the sediment will clog the emitters, and clogged emitters will make the irrigation system stop working. If you match the pipe diameter to the flow requirements and use the correct hardware, the irrigation system will deliver water to all plant effectively.