Cubic Feet Per Minute/Hour [1]

Units of measurement typically applied to the flow of liquids or gases or gases in a pipe or tube. A cubic foot is the volume contained in a cube that measures 1 foot on each of its sides. 

A flow rate of 2 cubic feet per minute means that a volume of 2 cubic feet is passing by a given point in a pipe or tube each minute. A flow rate of 2 cubic feet per hour means that a volume of 2 cubic feet is passing by a given point in a pipe or tube each hour.

See PEI/RP300 [2].