Kvs is a measurement of a valve’s flow capacity, calculated as follows: Add a pressure drop of 1 bar to a valve and allow it to run for one hour. The accumulated flow through the valve in cubic metres is equal to the Kvs value. Cv is the US unit and states the flow in gallons per minute at a pressure drop of 1 psi. A factor of 1.16 is used to convert from Kv to Cv (1.16 x Kv = Cv).