Module 4 ยท Pumps and Pressure
Surge and Water Hammer
A rapid change in water velocity can create a pressure wave called surge or water hammer. Fast valve movement, pump trips, check-valve closure, and sudden demand changes are common triggers.
Evidence may include sharp pressure transients, banging, pipe movement, relief operation, check-valve slam, or failures that appear after an event. High-speed data may reveal changes that normal displays miss.
The loudest location may not be the source, and simply restraining a moving pipe does not remove the hydraulic cause. The whole event sequence must be reconstructed.
After a power interruption, compare pump trip timing, valve closure, pressure traces, and surge-control status before restarting. Follow the approved sequence and inspect for damage.
Exam Need to Know
- Water hammer = pressure wave from a rapid velocity change.
- Triggers: fast valves, pump trips, check-valve slam.
- The loudest spot may not be the source.