This calculator uses AGA8-92DC compressibilty (z) to calculate the volume and energy of gas vented from an initial to a final gauge pressure. It also calculates the volume of gas remaining in the pipeline at the final gauge pressure. At zero final gauge pressure, the remaining gas corresponds to the purge volume to clear the pipeline.
This version of the calculator uses the following default criteria and features:
- default atmospheric pressure of 101kPa
- user input of gas temperature (-48 to 77 degC)
- 3 preset natural gas compositions (37.45, 38.5 and 40MJ/m3 heating values)
- selectable pipe diameter in mm or inches. The selected mm diameter is used as the internal diameter for the volume calculation
- pressure range is limited to 0kPaG to 30kPaG
The AGA8 calculation as implemented in this calculator is not certified. It implements the algorithm described in ISO 12213-2:2006 and has been successfully tested against the example calculations in annex 2 of the same standard. It has also been checked against other commercially available products for accuracy. Even so, its incumbent on the user to validate suitability for intended use.
See support website for details on gas compositions used in this calculator.