22mm/¾" tubing

Feb 06, 2005 10 Replies

I am about to fit a new bathroom suite which will involve alteration of the plumbing. The house was built in the 60's so I am assuming the pipework is in Imperial size. As I understand it, 15mm is compatible with ½" but I'm not sure about 22mm and ¾". I have tried a google groups search with no luck. Any advice would be gratefully accepted. Ed


I have joined the two with "end feed" fittings, you have to get *LOTS* of solder on the 3/4" inch end .....

Aparently you can buy adaptors

Rick

You'll need some adaptors. Both end feed and compression are available from a decent PM.

1/2" and 15mm pipes are virtually the same size. Compression fittings - and probably solder too - are completely interchangeable. 22mm pipe is slightly - but measurably - larger than 3/4" pipe. You can use 22mm compression fittings on 3/4" pipe with special 'imperial' olives.

If you want to join 22mm and 3/4" pipe with soldered connections, you can get special connectors whose 2 ends are slightly different sizes.

You can also buy these by mistake and spend a lot of time learning new words.

No significant difference in size that I'm aware of. They just started referring to them in metric. Imperial sized measurements are the INNER diameter of the pipe but metric size is the OUTER diameter. 1/2 inch pipe is near identical to 15 mm metric pipe and can normally be joined together no probs. Same goes for 22mm and 3/4 inch. Any 'odd' larger imperial sizes can be joined to metric using adaptors to sleeve them up or down.

Greg

You can certainly buy loose 3/4" olives for use in 22mm fittings. As far as I know there are no special 1/2" - 15mm olives - 'cos the same ones fit both pipe sizes.

Correct

Correct

No

3/4" 22mm falls in this category.

As a general point, solder used as a 'filler' has very little strength, compared to a close fitting soldered joint. Might not matter in most domestic circumstances, but you never know, and really not worth the risk.

I'm not saying your statement is wrong Dave but it does over egg things a bit. If thick solder was that weak we would never have used wiped lead joints for many years

The message from "John" contains these words:

I suspect that the problem in this case is that the clearance is just too great for capillary action to fill the whole joint. The thing about wiped joints is that they were thick. Turning the end feed fitting into a wiped joint should work but just feeding solder in is more likely to block the pipe than seal the fitting.

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