Fluid MechanicsFull Glossary

Cv (Flow Coefficient)

The numerical measure of a valve's capacity to pass flow. Defined as the flow in US gal/min of water at 60 degrees F with a 1 psi pressure drop. Higher Cv = larger valve capacity. Formula for liquids: Cv = Q x sqrt(SG / delta-P). European equivalent: Kv (m3/h at 1 bar delta-P). Relationship: Cv = 1.156 x Kv.

What is Cv (Flow Coefficient)?

The numerical measure of a valve's capacity to pass flow. Defined as the flow in US gal/min of water at 60 degrees F with a 1 psi pressure drop

Vajra Industrial Solutions is an engineering-driven industrial valve manufacturer and supplier. Concepts such as cv (flow coefficient) inform how we select, manufacture, and document valves for industrial service.

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Frequently Asked Questions

What is Cv (Flow Coefficient) in the context of industrial valves?

The numerical measure of a valve's capacity to pass flow. Defined as the flow in US gal/min of water at 60 degrees F with a 1 psi pressure drop. Higher Cv = larger valve capacity. Formula for liquids: Cv = Q x sqrt(SG / delta-P). European equivalent: Kv (m3/h at 1 bar delta-P). Relationship: Cv = 1.156 x Kv.

How does Cv (Flow Coefficient) affect valve selection and sizing?

The numerical measure of a valve's capacity to pass flow. Valve sizing must account for this phenomenon to prevent premature failure, excess noise, and vibration. For control valves, ISA-75.01 and IEC 60534-2-1 cover sizing for incompressible and compressible flow. Vajra Industrial Solutions can assist with valve sizing calculations - contact sales@vajravyuh.com with your process data sheet.

What valve types minimise Cv (Flow Coefficient) problems?

The choice of valve type and trim significantly affects susceptibility to flow-related problems. Anti-cavitation trims, low-noise cages, multi-stage pressure reduction, and proper Cv sizing reduce velocity-related damage. For critical applications, control valve sizing is performed using the ISA/IEC methodology with FL (liquid pressure recovery factor) and Fd (valve style modifier) for the specific valve geometry.

Reviewed by Engineering Applications Team, Vajra Industrial SolutionsDiscipline: Industrial Valve TerminologyLast reviewed: 20 June 2026

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