Maximum Gas pipe velocity

[huedem]

What is the typical natural gas pipe velocity? and what's the maximum gas pipe velocity?

[admin]

For underground installations it is normal to have about 20 m/s.
Maximum velocity in pipe line is defined by available pressure, but in control and safety valves it can be allowed up to 100 m/s.

[huedem]

Thanks for the information. I noticed from the pipeflowcalc, for 2inch pipe with 1,500 feet length, 90 psi in and 10 psi drop, it gives a result of 337 cfm gas flow with a 44 and 50 fps velocity. But shouldnt the velocity of this be 257fps (based on that 337cfm flow and 2inch pipe)?? In which case thats below 100m/s maximum. is this right?

[admin]

. But shouldnt the velocity of this be 257fps (based on that 337cfm flow and 2inch pipe)?? In which case thats below 100m/s maximum. is this right?

Why do you think it should be 257 fps? It should be 257 if pressure is at standard conditions at 1.013 bar, but as you have 90 psi (cca 6 bar) it is about 6 times less (257/6=44 fps - approx.)

[huedem]

Thanks very much. That explained it.

[huedem]

So it's acceptable to have a 20,000 cfh gas flow in a 2" pipe with 90 psi starting and drop of 10 psi? (yielding ~14m/s pipe velocity)??

[admin]

Yes, it is just about perfect.

[cpetersen]

At what point do you become concerned with the erosional effect of velocities as high as 100 m/s?

[admin]

If abbrasive material is present, it can cause erosion, but with clear gas, I think not.