🎯

Orifice Meter Calculator

Per ISO 5167-2:2003 with Reader-Harris/Gallagher

AGA Report No. 3 / ISO 5167-2 Orifice Meter Calculator
Calculates gas flow rates using the Reader-Harris/Gallagher discharge coefficient equation. Supports flange, corner, and D/D/2 tap configurations with iterative Reynolds number convergence and ISO 5167 compliance validation.
Calculation Mode:

Pipe & Orifice Dimensions

in
in

Operating Conditions

in H₂O
Typical: 10-200 in H₂O for optimal accuracy
psig
°F

Gas Properties

-
Natural gas: 0.55-0.70, Methane: 0.554
lb/lbmol
MW = SG × 28.97 (calculated from gravity)
-
Typical: 0.90-1.00 for natural gas
-
Natural gas: 1.27-1.31, Methane: 1.31

AGA-3 Flow Equation

Q = C·E·Y·(π/4)·d²·√(2·ΔP/ρ)
C = Discharge coeff. (Reader-Harris/Gallagher)
E = Velocity of approach = 1/√(1-β⁴)
Y = Gas expansion factor (ε in ISO)
β = Beta ratio = d/D

Standards & References

  • ISO 5167-2:2003
    Measurement of Fluid Flow by Orifice Plates
  • AGA Report No. 3
    Orifice Metering of Natural Gas
  • API MPMS Chapter 14.3
    Concentric, Square-Edged Orifice Meters