Flow Rates in Pipes
A guide the flow rates of pipes.
PIPE DIAMETER = NOMINAL TO PEAK FLOW
½” = 5 - 10 GPM
¾” = 10 - 15 GPM
1” = 16 - 30 GPM
1 ¼” = 30 - 35 GPM
1 ½” = 40 - 70 GPM
2” = 65 - 120 GPM
2 ½” = 80 - 170 GPM
3” = 120 - 270 GPM
4” = 250 - 500 GPM
6” = 500 - 1100 GPM
8” = 1000 - 2000 GPM
10” = 1500 - 3000 GPM
Quick Check – Flow Rate
Normal Flow Rate of a Pipe = D2 x 20
(Diameter Squared x 20)