The Operating Time Calculator allows you to calculate the Critical Closing Time (Tc) of a valve. Completely stopping the flow with a Tc greater than the calculated result (in seconds) can prevent water hammer. Simply select the diameter, SDR, material, and length of the system.

Note: Some types of valves have plugs that restrict flow only during the final portion of their stroke—for example, the last 10% (ball valves). These valves can generate water hammer despite long total closure times. For critical applications, it is always necessary to verify the characteristics of the valve plugs and define control strategies for starting and stopping pumps.