Black Plastic Pipe c1970

[Bas]

I've come across an unusual domestic pipe work situation in a 1970's house with original plumbing which is constructed of some kind of black plastic.

The main stopcock needs replacing. It's fed by black plastic mains pipe. The unusual thing (in my experience) is that the house is then plumbed with a hard PVC like black plastic pipe. It looks like the joints are glued and the pipe is about 15mm perhaps a little larger. As the stopcock is virtually innacessible my plan was to install a new stopcock just above it, but given this mystery pipe I'm now left wondering what to do. Can anyone offer any advice. What kind of joint can be used - will normal 15mm compression fittings work on the mystery pipe?
I don't really want to cut into the pipe to see if 15mm compression would work and then find I can't complete the repair!

Thanks in advance.

 

[kevplumb]

sounds like 3/8"" black alkathene you can get adaptors at most merchants

k1710kp

 

[Nige F]

sounds like 3/8"" black alkathene

With glued joints

 

[Bas]

A bit more research done - sounds like 1/2" Alkathene, asll I need to do now is find a merchant who can supply two adapters to 15mm and i'm away! Any suggestions for the best merchants. Doubt my local City Plumbing will be able to help.

 

[Nige F]

A bit more research done - sounds like 1/2" Alkathene, asll I need to do now is find a merchant who can supply two adapters to 15mm and i'm away! Any suggestions for the best merchants. Doubt my local City Plumbing will be able to help.

Philmac universal adapter from PTS

 

[Gasman1015]

Plumbcenter, and it is as Kev said 3/8 not 1/2 inch.

 

[Nige F]

sounds like 3/8"" black alkathene

With glued joints

Bloody ignore the glued joints then I recon it`s Polyork saw a lot of it while holiday cottaging in Devon

 

[chrishutt]

It's not Alkathene (polyethylene). It's Polyorc or similar (uPVC) but may have the same outside diameter, based on imperial steel tube measurements (?). The compression fitting may fit but the question is whether the uPVC can withstand the compression forces, especially without a liner.

 

[Gasman1015]

Yes chris, it is polyorc, there is a lot in this area, mainly 3/8 and 3/4, it can get quite brittle, but I have never had a problem using the compression fittings, it was all solvent weld but the joints are extremely difficult to source..

 

[chrishutt]

You can get uPVC pipes and fittings (Durapipe.co.uk, Pipestock.com) and the imperial sizes are, presumably, the same as in the 1970s, namely 17.1mm OD for 3/8", 21.4mm OD for 1/2", 26.7mm OD for 3/4", etc. You would need a plain uPVC to threaded adaptor. Note that the bore of 3/8" is actually 13mm (1/2"), etc. so actual sizes are bigger than nominal sizes.

 

[Bas]

Yes chris, it is polyorc, there is a lot in this area, mainly 3/8 and 3/4, it can get quite brittle, but I have never had a problem using the compression fittings, it was all solvent weld but the joints are extremely difficult to source..

Gasman - do you mean standard 15mm compression fittings?

Thanks to all for the advice - much appreciated. When I get to the bottom of this I'll share it with you. I don't think its Polyetheline either its too hard like PVC solvent Weld. Just black and a pain in the Bum!

 

[Gasman1015]

No, you need a straight coupler 3/8 to 15mm.

 

[chrishutt]

That's to 3/8" polythene, which has an OD of 17mm!

 

[Bas]

I've ordered a vernier caliper to measure the bloody thing!

 

[Bas]

Thanks again to everyone who advised. The OD is 17.1mm so it looks like 3/8ths it is. Just got to source the adaptors and I'll be happy!