What would the gpm of a 1.5" I.D. pvc pipe at 90 psi be?

Question

The pipe is horizontal with no restriction on the outlet of the pipe.

Answer 1

If you are speaking of 90 psi ( measured ) at the discharge end of the pipe, and 1.5 inch ID then you will have very close to 630 GPM.

Depending on the length of the pipe, and if you are feeding this pipe with a pump or source of pressure measured at 90 psi at the beginning of the pipe length, you will have less pressure at the discharge end from friction loss. And a corresponding decrease in GPM flow at discharge.

The FL figures for PVC I do not have at hand.

But would be figured on length, diameter and GPM flow.