cemented plastic pipe to compression fit

[andrews68]

Hi - I'm wanting to tap into an outside water supply in order to plumb in a stand-pipe in my yard (existing supply runs into a byre for livestock). The water supply is cemented plastic piping with an outside diameter of 21.5mm. Can I use compression fittings such as Hepworth style 'T'-piece on this, or if will I have to use cemented fittings as well?

Cheers, Andy.

 

[ChrisR]

Could someone have used overflow pipe?
There have been/are mains-bearing cemented pipe systems but they aren't common.
What colour iis it?

Is it a gravity (tank ) fed suoply?

 

[andrews68]

It probably is a gravity supply Chris, as I seem to remember there's not much pressure in it. The colour is brown.

 

[doitall]

Could be something like "Friatherm" solvent welded .

I would think a philmac universal coupling would do the job.

 

[andrews68]

Cheers for that. I've looked up both Friatherm and Philmac on Google. The Philmac does indeed look like it will do the job and the existing pipe-work does look like a Friatherm sample on Durapipe's website. What I can't understand is why people use cemented pipe for hot/cold water systems. It seems like just as much work as compression fittings and you can't check it for hours after until the solvent has set. The system runs through a wooden shed so soldered fittings would be unacceptable.

 

[doitall]

Friatherm is perhaps the best product on the market, and is invaluable for certain projects.

 

[andrews68]

Does that mean the best option would be to use Friatherm for the standpipe spur or use the Philmac converter and Hepworth style fittings thereafter instead? The standpipe will sit outside and it seems Friatherm is only recommended down to 0 degrees so I'm thinking plastic compression fittings are the best (I've only ever worked with copper soldered and compression fittings but plastic seems to be the way for speed...)

 

[doitall]

No Blue or black poly is best.

 

[ChrisR]

Go Poly, but protect from UV. Pain might be getting hold of a short length. You could always use 15/22mm Hepworth, Polypipe etc ordinary plumbing pipe, with the right connectors.

The solvent ones can be quite brittle.
They can be the cheapest overall in some applications eg if no flames allowed, and in practice a) never leak and b) don't need anything like as long as they say, before they're set.

 

[andrews68]

Thanks for that guys - it seems my best option then will be to use that Philmac T-piece and (because of I've got an unused roll of it taking up space in my attic) 15mm poly-pipe from thereon. Are those Philmac connectors readily available from Plumb Centre or Screwfix?