Emerson Process Management ControlWave EFM 3808 - Manual (Page 229)

CI-ControlWave EFM Appendix F / F- 29
FPV - Supercompressibility Factor (FPV) is displayed here.
Base Temperature - Required or Contract Base Temperature is entered here (Deg. F).
Base Pressure - Required or Contract Base Pressure is entered here (psig).
The following outputs from the AGA3 calculation are displayed:
MSCF/H - Flow rate in thousands of standard cubic feet per hour
Low Flow Cut Off - Cutoff (if the DP drops below the low flow cut off value) or OK
C Prime - Orifice Flow Constant
Fb - Basic Orifice Factor
Fr - Reynolds Number Factor
Y - Expansion Factor
Fpb - Pressure Base Factor
Ftb - Temperature Base Factor
Ftf - Flowing Temperature Facture
Fg - Specific Gravity Factor
Extension - Square Feet of the Product of Differential Pressure and Static Pressure
F.6.3.1.3 1992 AGA3 Equation Configuration
The user must configure the inputs to the equation.
Pressure Tap - The user mat toggle between pressure tap settings Flange/Upstrm and
Flange/Dnstrm.
Low Flow Cut Off - When the differential pressure drops below the low flow cut off value,
the flow rate will be set to zero. Default units are inches of water (H
2
O).
Orifice Diameter - Orifice diameter is entered here. Default units are inches.
Pipe Diameter - Diameter of the pipe is entered here. Default units are inches.
Orifice Temp. Coefficient - Orifice coefficient of thermal expansion is entered here
(Inches per Inch-degree F).
Pipe Temp. Coefficient - Pipe coefficient of thermal expansion is entered here (Inches per
Inch-degree F).
Isentropic Exponent - Gas Isentropic Exponent is entered here. This should not be
changed unless the Gas Isentropic Exponent is known to be other than the 1.3 value given
in the 1992 American Gas Association (AGA3) Report.