Plumbers usually measure flow rates in terms of the volume of water that passes each minute. Convert this value to velocity using the pipe's size.

- Skill level:
- Easy

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## Instructions

- 1
Multiply flow rate in gallons per minute by 0.408. For instance, if the flow rate is 50 gal / min:

50 * 0.408

= 20.4

- 2
Square the pipe's diameter, in inches. For instance, if the pipe measures 4 inches across:

4 * 4

= 16

- 3
Divide the answer to step 1 by the answer to step 2.

20.4 / 16

= 1.275

This answer is the water velocity in feet per minute.