Alkathene pipe & stop tap question.

[Steven Briggs]

Currently refitting the bathroom down at Mum's 70's bungalow.

Main water supply comes in to a stop tap in the bathroom, below the LHS of the toilet cistern. New cistern has the inlet on the RHS so I was thinking of moving the stop tap to the right for a neater job. Anyway, this afternoon, I had to quickly rip out the old bog and lift the floor boards as I thought I had a leak under the floor*. Anyway, I now know the incoming supply is a black plastic pipe, 22mmm OD, presumably the old alkathene stuff.

Question is, do I need special fittings for this or will just fit a normal 22mm compression stop-tap? Can 1/4 turn ball valves be used in this position (more reliable?)

*Leak turned out to be inside the body (i.e. cold to hot) of the new bath mixer. Grrrr.

[Ed Sirett]

The pipe is more likely 20mm OD. UNless you measured it accurately in which case I apologize.

Whatever you do any form of compression fitting on plastic pipe needs a support insert in the end.

[Steven Briggs]

In message , Ed Sirett writes

Dead on 22mm, measured with verniers. As the pipe was painted above floor level, I had assumed it was copper until I pulled up the floor boards and saw it was actually black plastic. A google revealed a couple of threads suggesting this stuff is very thick walled, so I not sure it does need an insert, or if a standard 22m olive will do the job.

[Ed Sirett]

The blue stuff is certainly 20/25/32mm.

A push fit type joint will likely be better than a compression one if you have no support inserts.

[Holly, in France]

These pipes come in different thicknesses, one more heavy duty than the other. Well, in Ireland and France they do, I assume also in the UK. The fittings for them are easily available in plumbers merchants and agricultural suppliers, and you would also get a fitting where one end goes onto the alkathene and into which you can screw a fitting for copper into the other end if necessary. I bought a 1/4 turn one recently, but I'm sure you would get a tap type aswell. Probably just as easy and no more/not much more expensive than an ordinary fitting.

Holly

[Grimly Curmudgeon]

It was somewhere around Barstow, on the edge of the desert, when the drugs began to take hold. I remember Ed Sirett saying something like:

The really thick-walled 22mm stuff can be used with an olive and no insert... I have one outside that's being resisting mains pressures of up to 10bar for 6 years.