UN-101: Gas Coriolis(Calc Dens, Calc Std Dens, Calc CV)


Calculates the uncertainty in mass, standard volume and energy flowrate for a gas Coriolis meter run. Mass flowrate, density, standard density and CV calculations and their uncertainties are performed using user-selectable calculations. Pressure and temperature uncertainties are determined using the technical specification for the transmitters selected from the integrated transmitter selection tool.


The General tab is used to enter information, which is saved along with the uncertainty calculation and included in reports which are generated.

The tabs used for inputting data and calculating the uncertainty in the individual components of the uncertainty can be seen along the top of the module window.

The report tab is only visible once the calculation has been run and will not be visible if any parameters are changed until the calculation has been run once more.



Pressure units

This section gives the option of entering the pressure as either an absolute value or as a gauge value with reference to atmospheric (barometric) pressure. If Absolute is selected inputs are required for Absolute pressure and Atmospheric pressure and if Gauge is selected inputs are required for Gauge pressure and Atmospheric pressure. This ensures that whichever is chosen both the Gauge and Absolute pressure value is available to other sections of the module.

For example: the Density calculation tab may require an absolute pressure to perform an AGA 8 calculation and the Gauge pressure may be used for the pressure transmitter calculation.

Absolute pressure – the Atmospheric pressure = Gauge pressure


Mass flow rate

This is the mass flow rate through the Coriolis meter.


This is the operating pressure of the Coriolis meter.

Note: As described above, if Absolute is selected inputs are required for Absolute and Atmospheric pressure and if Gauge is selected inputs are required for Gauge and Atmospheric pressure.

The default value for Absolute Pressure is set to 1 standard atmosphere (1.01325 bar)


This is the measured temperature of the gas stream.


The outputs section shows the calculated flow rate and uncertainty taken from the Flow Rate tab.

Calculation Blocks

The following blocks are used within this uncertainty module:





Standard Density

Calorific Value

Gas Coriolis Flow Rate