Doug Miller wrote:
In article .com,
wrote:

Pipe of the same nominal size is the same OD regardless of schedule,

but not the same regardless of material.
E.g. nominal 3/4" steel, copper, PVC,
and CPVC pipe are different sizes.


3/4" schedule 40 steel pipe has an OD Of 1.050" and a
wall thickness of 0.113" for an ID of 0.774".

See:

http://www.interpipe.com/Pipe_Dimens...nd_Weights.htm
http://www.gkctcc.com/pipe_dimensions.htm
or
http://www.inter-mountain.com/line_pipe.htm

(all good sources)

3/4" schedule 40 PVC pipe has an OD Of 1.050" and a
wall thickness of 0.113" for an ID of 0.774".

http://www.pvcplus.com/PVC%20schedule_40_&_80_pipe.htm

Looks the same to me.

I didn't check on other materials but it appears that
ASTM D-1785 codifies the dimensions. That'd be the place
to see if the standards vary by material.

--

FF