Water - Max. Suction Flow Velocities vs. Pipe Size

Recommended maximum water flow velocities on suction sides of pumps. Keep suction fluid flow speed below specified values to avoid capacity problems, cavitation, and high power consumption.

Pipe Bore (inches)	Pipe Bore (mm)	Max. Suction Velocity (m/s)	Max. Suction Velocity (ft/s)
1	25	0.5	1.5
2	50	0.5	1.6
3	75	0.5	1.7
4	100	0.55	1.8
6	150	0.6	2
8	200	0.75	2.5
10	250	0.9	3
12	300	1.4	4.5

Calculator

Inputs

Flow Rate (m³/h)

Pipe Bore (mm)

Results

Flow Velocity-- m/s

Flow Velocity-- ft/s

Notes

Key Points:

Capacity problems, cavitation, and high power consumption in pumps often result from suction side conditions
As a rule of thumb, keep suction fluid flow speed below the recommended values in the table above
Use the calculator above to determine your system's flow velocity for a given flow rate and pipe size
Compare your calculated velocity against the maximum recommended velocity for your pipe size

Related Topics:

Cavitation and NPSH (Net Positive Suction Head) - important for understanding suction-side performance