Oxygen & Helium Flow characteristics?

[budsned]

I'm trying to find equations for pressure drops for gaseous flow of oxygen and helium in small pipes (tubing). The air flow calculator does not provide for differences in specific gravities, friction characteristics, etc. Can anyone help me with a suitable equation or calculator?

[admin]

For isothermal flow you can use following equations:
http://www.pipeflowcalculations.com/pip ... l-flow.php