What do "Static Head" and "Friction Head" mean, and what do they have to do with my sump pump?
Vertical Lift, also known as Static Head, is the height that water has to travel as it moves through your discharge pipe. To estimate this, measure the vertical distance from where water enters your sump pump to where the discharge pipe turns from vertical to horizontal.
As this distance increases, your pump has to work harder to push water out through your discharge piping. When you’re shopping for a sump pump, find out its GPH (gallons per hour) capacity at the static head measurement for your basement.
Friction Head, also known as Friction Loss:
- As water flows through your discharge pipe, friction is created, from water rubbing against the inside of the pipe.
- This slows down the water flow, and your pump must overcome this friction.
General Rules of Thumb about Friction Head:
A narrower discharge pipe will create more friction than a wider one.
Pipe fittings, like elbows and check valves, create friction.
The longer your discharge pipe, the more friction is created.
If you think friction could be an issue for your sump pump system, consult a plumber to find out how much friction is created in your discharge piping. They can give you a Friction Head estimate, which you then add to the Vertical Lift (Static Head) to arrive at a Total Dynamic Head that your sump pump must push against.
Use this Total Dynamic Head figure when shopping for a sump pump to determine the pump’s capacity once it’s connected to your specific discharge pipe system. Most sump pumps’ literature shows their pumping rates at different lengths of head.
This article is intended for informational purposes. Before beginning any construction project at your home, please ensure that you take necessary safety precautions and consult construction professionals whenever necessary.