[MrForbes]

Sure it makes sense, but only if you understand what they are saying...and center-to-center measurements are common in many engineering fields.

The distance between the pipes is just the center-to-center distance, minus the diameter of the pipe (or, minus two times half the diameter of the pipe, which is the same thing)

With 1.5" outside diameter pipe, and 32" center-to-center spacing, the distance between the bars is 30.5"