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AGA5
American Gas Association Report No. 5 Module
ACCOL II Reference Manual
Page AGA5-1
The AGA5 Module performs AGA-5 calculations for conversion of
computed gas volume to energy equivalents as described in the Ameri-
can Gas Association Report No. 5, reference Catalog No. XQ0776.
Module Terminals
VOLUME
represents the metered volume of gas in MSCF or flow rate in MSCFH
BASE_PRESS
is the base pressure of the flowing gas
BASE_TEMP
SPEC_GRAV
VOL_%_HE
VOL_%_CO
FPV_IN
VOL_CONVERS
ENERGY_CONV
OUTPUT
VOLUME
BASE_PRESS
5
VOL_%_N2
VOL_%_O2
VOL_%_CO2
VOL_%_H2O
VOL_%_H2S
VOL_%_H2
Default: None, entry is required. No
computation will be performed if
this terminal is not wired.
Format: Analog signal
Input/Output: Input
Default: 14.73
Format: Analog signal or constant
Input/Output: Input
AGA5
ACCOL II Reference Manual
Page AGA5-2
AGA5
American Gas Association Report No. 5 Module
ACCOL II Reference Manual
Page AGA5-2
AGA5
American Gas Association Report No. 5 Module
Default: 600F
Format: Analog signal or constant
Input/Output: Input
Default: 1.0
Format: Analog signal or constant
Input/Output: Input
Default: 0.6
Format: Analog signal or constant
Input/Output: Input
Default: 0.0
Format: Analog signal or constant
Input/Output: Input
BASE_TEMP
is the base temperature of the flowing gas
FPV_IN
is the supercompressibility factor of the gas. This factor is used in
equations when the input volume is an uncorrected metered volume.
Originally, the AGA-5 Report included the FPV factor in its calcula-
tions. However, since that time, the report has been found in error. It
is therefore recommended that this terminal not be wired in which
case the default value of 1.0 is assumed.
SPEC_GRAV
is the specific gravity of the flowing gas.
VOL_%
The VOL_% terminals contain the following:
VOL_%_CO2 - the volume % of CO2 present in the gas.
VOL_%_N2 - the volume % of N2 present in the gas.
VOL_%_O2 - the volume % of O2 present in the gas.
VOL_%_HE - the volume % of He present in the gas.
VOL_%_CO - the volume % of CO present in the gas.
Default: 600F
Format: Analog signal or constant
Input/Output: Input
Default: 1.0
Format: Analog signal or constant
Input/Output: Input
Default: 0.6
Format: Analog signal or constant
Input/Output: Input
Default: 0.0
Format: Analog signal or constant
Input/Output: Input
BASE_TEMP
is the base temperature of the flowing gas
FPV_IN
is the supercompressibility factor of the gas. This factor is used in
equations when the input volume is an uncorrected metered volume.
Originally, the AGA-5 Report included the FPV factor in its calcula-
tions. However, since that time, the report has been found in error. It
is therefore recommended that this terminal not be wired in which
case the default value of 1.0 is assumed.
SPEC_GRAV
is the specific gravity of the flowing gas.
VOL_%
The VOL_% terminals contain the following:
VOL_%_CO2 - the volume % of CO2 present in the gas.
VOL_%_N2 - the volume % of N2 present in the gas.
VOL_%_O2 - the volume % of O2 present in the gas.
VOL_%_HE - the volume % of He present in the gas.
VOL_%_CO - the volume % of CO present in the gas.
AGA5
American Gas Association Report No. 5 Module
ACCOL II Reference Manual
Page AGA5-3
VOL_%_H2S - the volume % of H2S present in the gas.
VOL_%_H2O - the volume % of H20 present in the gas.
VOL_%_H2 - the volume % of H2 present in the gas.
VOL_CONVERS
is a volume conversion factor, that is, a metered volume of cubic feet
at 14.73 psi, 600F. If the value on the VOLUME terminal is expressed
in terms of MSCF or MSCFH, you may use the default which is
1000.0. If VOLUME is expressed in terms of SCFH or SCF, set this
terminal to 1.
ENERGY_CONV
is an energy conversion factor when dekatherms are the desired
energy units.
OUTPUT
is the desired units of gas energy, normally in dekatherms or dekath-
erms/hour. It is the flow rate calculated by the module.
Default: .000001 dekatherm (1 deka-
therm = 1,000,000 BTUs)
Format: Analog signal or constant
Input/Output: Input
Default: 1000.0
Format: Analog signal or constant
Input/Output: Input
Default: None
Format: Analog signal
Input/Output: Output
ACCOL II Reference Manual
Page AGA5-4
AGA5
American Gas Association Report No. 5 Module
ACCOL II Reference Manual
Page AGA5-4
AGA5
American Gas Association Report No. 5 Module
Module Equations
The equation implemented by this module is taken from Section II of
AGA Report No. 5. This particular equation dovetails the require-
ments of the orifice metering approach and the volume metering
approach. As such, several of the factors are not required for the
orifice metered volume to energy conversions. This module is only
used when a calorimeter signal is not available. It performs the
following equation for gas volume-to-energy conversion:
Ue = Uv * Ev * Fuv * Fue
where:
Ue = Desired units of Gas energy, totalized or rate per unit of time.
Uv = Standard volume units, totalized or rate per unit time, i.e.
SCFH. Note that Uv is normally calculated by AGA-3 or AGA-7
modules in MSCFH.
Ev = Energy-volume ratio, Btu per cubic foot, 14.73 psi, 60
0F.
Fuv = Volume conversion factor, metered volume to cubic feet at
14.73 psi, 600F. Note: Where Standard units are metered in
MSCFH, Fuv = 1.
Fue = Energy conversion factor, Btu per cubic foot to desired energy
units. Note: Where dekatherm energy units are required, this
factor equals one. (One dekatherm = 1 million BTUs)
If a calorimeter signal is available, do not use this module. Instead,
use a Calculator Module to solve the following equation:
Ue = Uv Ev (.000001)
The parameters of this formula are defined above. If Uv is expressed
in units of MSCFH, change the multiplier in the equation to .001.
Module Equations
The equation implemented by this module is taken from Section II of
AGA Report No. 5. This particular equation dovetails the require-
ments of the orifice metering approach and the volume metering
approach. As such, several of the factors are not required for the
orifice metered volume to energy conversions. This module is only
used when a calorimeter signal is not available. It performs the
following equation for gas volume-to-energy conversion:
Ue = Uv * Ev * Fuv * Fue
where:
Ue = Desired units of Gas energy, totalized or rate per unit of time.
Uv = Standard volume units, totalized or rate per unit time, i.e.
SCFH. Note that Uv is normally calculated by AGA-3 or AGA-7
modules in MSCFH.
Ev = Energy-volume ratio, Btu per cubic foot, 14.73 psi, 60
0F.
Fuv = Volume conversion factor, metered volume to cubic feet at
14.73 psi, 600F. Note: Where Standard units are metered in
MSCFH, Fuv = 1.
Fue = Energy conversion factor, Btu per cubic foot to desired energy
units. Note: Where dekatherm energy units are required, this
factor equals one. (One dekatherm = 1 million BTUs)
If a calorimeter signal is available, do not use this module. Instead,
use a Calculator Module to solve the following equation:
Ue = Uv Ev (.000001)
The parameters of this formula are defined above. If Uv is expressed
in units of MSCFH, change the multiplier in the equation to .001.
AGA5
American Gas Association Report No. 5 Module
ACCOL II Reference Manual
Page AGA5-5
For undiluted hydrocarbon gas mixtures,
Ev = Vg
where:
Vg = (1571.5 * specific gravity) + 144
For gas mixtures containing non-hydrocarbon compounds,
EV = Vg - (Vcd + Vn + Vo + Vhe + Vcm + Vhs + Vw - Vhy)
where:
Vcd = (Volume % CO2) * 25.318
V
n
= (Volume % N
2
) * 16.639
Vo = (Volume % O2) * 18.801
Vhe = (Volume % He) * 3.612
Vcm = (Volume % CO) * 13.424
Vhs = (Volume % H2S) * 13.462
Vw = (Volume % H2O) * 11.214
Vhy = (Volume % H2) * 0.713
If the input volume is a metered volume, then Standard Volume Units
are calculated from the metered volume as follows:
Uv = Fp * Ft * Fpv
2 * metered volume
where:
Fp = Pressure Factor = PSIA * .067889
Ft = Temperature Factor = (519.67 / (459.67 + 
0F))
Fpv = Supercompressibility Factor
Metered Volume = Volume displaced in unitspeculiar to
meter, at prevailing pressure and temperature conditions.
ACCOL II Reference Manual
Page AGA5-6
AGA5
American Gas Association Report No. 5 Module
ACCOL II Reference Manual
Page AGA5-6
AGA5
American Gas Association Report No. 5 Module
Since the energy conversion factors only apply to volume units under a
pressure of 14.73 psi and 600F, the above conversion also provides a
secondary volume conversion when the input volume is an orifice
metered volume expressed at base conditions other than 14.73 psi and
600F. In this case,
 519.67
Uv = Q * (Pb * 0.067889) *
459.67 + Tb
where:
Q = volume of gas at any other base conditions.
Pb = Any other pressure base, psia.
T
b
= Any other temperature base, 0F.
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