What is “Friction Loss”?
Friction loss is the energy taken by the inside of tubing, pipe and irrigation components. While water is moving around a system enclosed in pipes and valves, it is coming in contact with a lot of different surfaces. These surfaces one at a time steal a little bit of energy. To combat this challenge a simple reference chart is used to ensure the internal surfaces of a system do not compromise component demands. It is important to note that PE or polyethylene tubing has a higher friction loss than rigid PVC. While tubing flexibility may be important for a grower, keep in mind water moves slower through polyethylene than rigid PVC.
Another variable to take into account is fittings. Fittings take up energy every time water is rerouted. When possible use sweeps (45 degree elbows) or limit elbows and tees. For every 1’ of 1” PVC decline we gain 1 pound of pressure and for every 1’ of vertical climb we lose 1psi. An installer can see very quickly why a 10’ vertical climb may significantly compromise system demands. 10’ Vertical = -10psi
Imagery: Illustration demonstrating loss in flow through pipe and component.