Public BetaOpen test period: August 30–September 13, 2026. Preliminary engineering calculation—verify results before use.

Flow & control valves / Tools 01–02

Gas Valve Sizing

Calculate either the required control-valve Cv or the available standard gas flow through a valve with known Cv.

Standard-flow basis60°F · 14.696 psiaSCFM is converted internally to SCFH

IGToolsM&H Engineering LLC

Calculation reportGas Valve Sizing

Required Gas Valve Cv

Calculator v0.3.0 · Revision 2026-08-30 · Generated 8/31/2026, 1:27:59 AM

Required valve coefficient8.259 CvSubcritical flow predicted

Input snapshot

Gas: Nitrogen
Standard flow: 1000 SCFM
Valve coefficient: 25 Cv
Temperature: 60 °F
Inlet pressure: 200 psig
Outlet pressure: 50 psig
Specific gravity: 0.967
Compressibility Z: 1.0
Heat-capacity ratio k: 1.4
Valve xT: 0.70
Piping factor Fp: 1.0
Flow basis: 60°F · 14.696 psia

Calculated details

Inlet absolute pressure: 214.696 psia
Outlet absolute pressure: 64.696 psia
Pressure-drop ratio: 0.6987
Expansion factor Y: 0.6673

Preliminary engineering calculation only. Confirm gas properties, valve coefficients, applicable codes, noise, trim, travel, installed geometry, and manufacturer corrections before selection or operation.

Calculation method

Transparent engineering basis

Normalize conditions

Convert psig to psia and °F to °R. Convert SCFM to SCFH.

Check flow regime

Compare actual pressure-drop ratio with Fk·xT to identify choking.

Solve Cv or flow

Apply the expansion factor and solve the compressible-flow equation for the selected output.

Required CvCv = q / [1360 · Fp · P1 · Y · √(xeff / (Gg · T1 · Z))]

Available flowq = 1360 · Fp · Cv · P1 · Y · √(xeff / (Gg · T1 · Z))

References, conventions, and revision

Calculation structure follows the compressible-fluid method described by ANSI/ISA-75.01.01 / IEC 60534-2-1. This beta omits several manufacturer-specific corrections.
Pressure conversions use 1 standard atmosphere = 14.6959 psi, consistent with the NIST pressure conversion reference.
Preset gas values are approximate ambient-condition screening values. Molecular and heat-capacity data can be checked through the NIST Chemistry WebBook. Natural-gas composition is project-specific.
Website standard-flow convention: 60°F and 14.696 psia. Confirm that this matches the project, contract, meter, and vendor basis.

Calculator version: 0.3.0 · Revision date: 2026-08-30

Preliminary engineering calculation only. Excludes Reynolds correction, derived xTP, valve travel, noise prediction, trim selection, and manufacturer-specific corrections. Confirm gas properties and valve coefficients with the selected manufacturer.