On 27/04/2018 08:08, PeterC wrote:
On Thu, 26 Apr 2018 20:39:48 +0100, Steve Walker wrote:

On 26/04/2018 19:56, Tim+ wrote:
Nightjar Wrote in message:
On 26/04/2018 17:25, Jim K wrote:
Anyone know the i.d. of 50mm plastic waste pipe?

50mm *is* the ID. The OD will be 54mm if you have push fit pipe or 56mm
for solvent weld pipe.


That's confusing. I thought the convention was that "pipe" is
sized according to its external dimension (hence compatibility
between 15mm pipe of different materials) whilst "tube" was done
on internal diameter.

The convention falls apart in places. Anyway, "copper pipe" is of course
really "tube"

It's even worse when you mix imperial and metric: as you say, 15mm
(external) tube is interchangeable with 1/2" (internal) pipe - and they
are both copper, both tube (or both pipe if you prefer), but measured
differently!

SteveW

Fridge pipe/tube is always OD. Most joints are flair, so OD is crucial.
(Note to self: always remember to put on the back nut /before/ making the
flair, especially in 1"+ pipe!).

If you want a good mistake with tubing: a colleague of mine thought
(wrongly) that we needed some tubing for part of a temporary test set up
and bought some 2" stainless-steel tubing, a couple of 2" Swagelok
elbows and a couple of tees. At the time (mid '90s), an elbow was over
£300 !

SteveW