In article , Gordon Shumway wrote:
On Sat, 26 Jun 2010 03:40:58 GMT, (Doug Miller)
wrote:

In article unications,
(Robert Bonomi) wrote:

Plumbing stuff is specced by inside diameter.

Incorrect.

O.D. is whatever the manufacturer feels like.

Incorrect.

Pipe is specified by OD; the ID is determined by the nominal OD and the wall
thickness.

Think about it: if OD were "whatever the manufacturer feels like" you wouldn't
be able to use Manufacturer A's fittings with Manufacturer B's pipes. It's
precisely to ensure such interchangeability of pipes and fittings across
brands that the sizes are specified by OD, not by ID.

You are wrong and I am man enough to admit it. Hoses are measured by
I.D. Tubing is measured by O.D.

Nobody's talking about either hoses or tubing. We're talking about pipes.

For example with copper. We have various "Types," L, M, N and there
may be others. For a given size they are all the same O.D. The
different wall thickness will yield a different I.D. but they will all
use the same fittings because their O.D.'s are the same.

Which is exactly what I said: the OD is the same, and the ID varies depending
on the wall thickness as determined by the pipe schedule.