How do you convert gallons per minute to feet per second?

Answer 1

First convert gallons to a volumetric unit like cubic ft (ft^3)

7.48 gal per ft^3

Then divide the ft^3 quantity by the cross sectional area of the pipe (converted into square feet ft^2)

This will leave you with linear units of feet. This number of feet must travel past a point in the pipe in one minute to deliver a gallon.

You can then do the time conversion to obtain ft/sec from ft/min.

Consider a cylinder with a diameter equal to the pipe inside diameter. How tall would that cylinder have to be in order to hold a gallon of water. Its the same type of problem only with the added twist that the water is flowing past a point in a given amount of time.