1/2 PIPE ....??? Not 1/2....

1/2" pipe is not 1/2" because the 1/2 is the NPF (Nominal Pipe Size) basically the inside diameter of the pipe. Add to that number the wall thickness to get OD. So a 1/2 NPF Schedule 80 pipe has a wall thickness of .147 inches. So .5 + 2(.147) = .794 OD.

Now if you want 1/2 inch OD the closest you are going to get is 1/4" Schedule 80 or Schedule 80S. This pipe has an inside diameter of .25 and a wall thickness of .119. So that gives us .25 + (2*.119) = .488 OD.

~Michael