Which action helps mitigate water hammer in irrigation piping?

• A. Using slow-close valves, air chambers, and proper pipe sizing.
• B. Increasing mainline pressure dramatically.
• C. Using only rigid materials.
• D. Removing air from the system after installation.

Answer: (A)

Water hammer happens when a valve or pump closes or changes flow abruptly, creating a pressure surge that can shake pipes and cause damage. The best way to reduce that surge is to slow down how quickly the flow is interrupted and to give the system a cushion to absorb the energy. Slow-close valves reduce the instantaneous change in flow, letting pressure rise more gradually. Air chambers provide a compressible cushion that absorbs part of the surge when pressure spikes occur. Proper pipe sizing helps by keeping flow velocities and energy in check, so the resulting pressure rise is smaller and easier to manage. Pushing mainline pressure higher would magnify the surge and make hammer worse. Rigid materials offer little to dampen shocks and can transmit hammer through the system. Removing air after installation removes the cushion that helps dampen shocks, potentially increasing hammer. So the combination of slow-closing valves, air chambers, and appropriate pipe sizing effectively mitigates water hammer.