Pipe Sizing & Reynolds

Pipe sizing is a velocity choice: too slow and the pipe is expensive, too fast and you get noise, erosion and pressure loss. Pick a customary velocity, get the bore from A = Q/v, then check the Reynolds number.

Pick the next standard pipe size at or above the low-velocity bore. Then get the actual pressure drop from the Pipe Pressure Drop tool — velocity alone does not tell you the head loss.