Water Hammer 101

Water hammer (or hydraulic shock) is the momentary increase in pressure inside a pipe caused by a sudden change of direction or velocity of the liquid in the pipe. Water hammer can be particularly dangerous because the increase in pressure can be severe enough to rupture a pipe or cause damage to adjoining flow control equipment.

Proper valve operation time can be calculated through surge analysis and thus can be completely avoided. Through proper pump station design the correct valve choice can be made to ensure when a pump stop or start sequence is initiated the isolation control valve will be “smart” enough to eliminate any surge upon pump start or hammer upon pump stop.