Wayne Whitney wrote:
On 2005-03-15, William W. Plummer
wrote:

I made up a little spread sheet. It assumes 1/32" wall on the
pipe.

Pipe is measured by ID, not OD. Tubing is measured by OD.


That is a common misconception Try taking a ruler to 1/2"
nominal Schedule 40 pipe sometime.

Pipe of the same nominal size is the same OD regardless of schedule,
but the nominal size is always less than the actual OD, and
usually less than the ID too. It may be that the nominal
sizes were established by taking the ID of schedule 40 pipe
and subtracting some nominal allowance for accumulated scale
but I have never seen that in writing anywhere.

However tubing IS measured by the OD and the nominal size is the
same as the OD.

--

FF