So according to Wrought Steel Pipes - Bursting Pressures vs. Size (Not sure if it is a correct reference), a pipe with 2 inches dimension has working pressure of 650 psi, so I changed them to Pascal.
But the same website states that speed for hydrogen in steel pipe should only be 20 m/s (Pipe Line Velocities vs. Fluid), so if
then I must be wrong somewhere …
I would probably adjust the inlet pressure, so that the outlet speed is 20 m/s. Thank you Sebastian