Cv Value For Water. Use this in table 1. Specific gravity (1 for water) v:
A valve has a published cv of 5.4 on 60°f water. C v calculator for valve sizing. Cv = (25 gpm) (1 / (1 psi))1/2.
The flow coefficient or cv of a coupling is defined as the volume of water in us gallons per minute that will flow through the coupling with a pressure drop of 1 psi.
Where r is the universal gas constant. The use of this flow coefficient (c v) calculator leads to a standard calculation to compare valve capacities. However flow is expressed in units of cubic. Thus a cv flow coefficient of 10 indicates that a 1.0 psi pressure drop will occur with a 10 us gpm of water throughput through the valve.