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KV-value for gas

Calculates what the Kv-value of a valve in a gas system will depend on flow and pressure.

KV-value for gas

Input Result
Flow qn=
Temperature before valve T1= ˚C ˚C
Pressure before valve P1=
Pressure after valve P2=
Density ρn= kg/m3 kg/m3
KV m3/h m3/h
CV Usgal/min



Refers to how great the pressure before and after the valve is.


How big flow passing the valve.


Does the temperature of the medium before it reaches the valve.


The density of the gas passing through the valve. In the original case, the liquid is assumed to be water.


KV = Water flow in m3 / h at a pressure drop across the open valve of 1 bar (100 kPa).

kvs = The selected valve Kv-value at fully open valve. Typically a 30% safety margin to the calculated Kv value.

Difference between Kv and kvs
Kv-value the value component and have KV-value is the value that the component is expected to have operating case.

CV value

CV-value is the American equivalent to CV value. CV-value is defined as the water flow in U.S. gallons over a fully open valve with a pressure of 1 psi.


KV value subcritical: subcritical gas KV value subcritical
KV value supercritical: supercritical gas KV value supercritical
CV-value: CV-value for gas