3. Unfortunately no single recommendation will be correct for all possible circumstances, but the
table below can be used as a general guidance for the water flow capacity in Steel pipes schedule
40:
Pipe Size
(inch)
Maximum Flow
(gal/min)
Velocity
(ft/s)
Head Loss
(ft/100ft)
2 45 4.3 3.9
2 1/2 75 5.0 4.1
3 130 5.6 3.9
4 260 6.6 4.0
6 800 8.9 4.0
8 1,600 10.3 3.8
10 3,000 12.2 4.0
12 4,700 13.4 4.0
14 6,000 14.2 4.0
16 8,000 14.5 3.5
18 10,000 14.3 3.0
20 12,000 13.8 2.4
24 18,000 14.4 2.1