Plastic or Copper at Mains pressure

[Matthew]

Hi,

We have recently moved into a new house and are keen to have a megaflow (mains pressure) boiler fitted to improve the water pressures upstairs. I noticed that a lot of the bathroom pipework is the new pushfit plastic pipe stuff. Will this be able to withstand mains pressure if we have a megaflow boiler fitted or would we have to replace it with copper? Ive no idea how good this plastic stuff is (Ive only ever used copper), it does seem to be very popular. How reliable is it and what sort of longevity do you get from the fittings?

Thanks for any info, Matthew

[Grunff]

Yes.

No.

Most makes are very good.

On the whole, very reliable. Various manufacturers quote different life spans for their products, but 20-50 years is the usual range.

[Christian McArdle]

Don't worry. It's fine, provided it was installed properly.

Christian.

[Doctor Drivel]

Consider a heat bank/thermal store. Look at:

for an explanation. And annual service as with a megalflow, and about the same price or cheaper. And no potentyial explosions. A BBA approved man has to fit a Megaflow.

Plastic is common enough, although only has 15% of the UK market. Try to use compression joints instead of pushfit on the plastic pipe, as they are more reliable.

[Doctor Drivel]

The pipe is, but pushfit is viewed with caution by the trade because of constant leaks from the stuff. They can just shoot off the end of the pipe.

But not yet proven.

[Grunff]

I have some underground fittings with EDPM O rings which are ~30 years old. Same type of O ring is used in pushfit, and very similar pipe grab mechanism.

[Doctor Drivel]

On cold water pipes that are supported all around and don't sag and put pressure on the joints. Look at the hot pushfit pipes and fittings which sag when hot, a different kettle of fish. I'm still waiting for the poly hot water cylinder. Not yet.

[Grunff]

Not really - pipes should be well supported regardless. The manufacturers state this pretty clearly.

Soldered fittings are not meant to be load bearing either - repeated stressing results in eventual failure. This is not uncommon around CH pumps, where high levels of vibration exist. Clips are an important way of damping thus vibration.

[Doctor Drivel]

I was referring to your underground pipe which is supported all around the pipe and along its length. It is also cold water too. Everything is going for it.

NO fitting or pipe is to support a load, the exception being in-line controls, like pumps, etc, and they should be supported at each end.

The best are rubber grommet clips around the pump that absorb vibration.

[John Schmitt]

I still bitterly regret not having a digital camera when I visited Eastbourne. In one of the pubs in the pedestrian zone, full of old codgers, the gent's loo had a hot water pipe which had "sagged" *upwards*. Plastics have a greater coefficient of expansion than most, if not all, metals. The compressive force forces the pipe to buckle. Settle for that or banging pipes.

John Schmitt

[Matthew]

Thanks for the info chaps.

You can understand my concern with regard to reliability. Lets face it if you have a leak from a gravity system then its bad but hopefully not too much damage. I would imagine a leak from a megaflow hot water pipe would also be mega-destructive!. We had a leak years ago in our old house and the kitchen ceiling was ruined. I dread to think what might have happened if we'd have had a megaflow then!!

Thanks, Matthew

[Chris Bacon]

Matthew wrote: can understand my concern with regard to reliability.

I must say I still prefer copper, if it's a job for me. Even if well-clipped, plastic still sags, and doesn't look so "neat", + there's that "what if" feeling that you mention.

[David]

In article , Doctor Drivel writes

Not so, pushfit is becoming the norm for the trade

Yes it is

[Doctor Drivel]

With 15% of the market? It is used extensively in new builds so they can use unskilled labour for the first fix and full pros for the second and the Pikies don't pinch it because it is not copper.

Those who do not do new builds are finding it does not live up to its promises. Cowboys use it a lot. Moany use cheaper and better compresion joints when joining plastic.

Again. But not yet proven. As we haven't reached the 50 years it is not proven. More like we are in year one. Hepworth are in their third fitting redesign.

You must stop making things up.

[David]

In article , Doctor Drivel writes

That figure is out of date, read what I wrote

Not so, look in any plumbers van.

So you're saying that we have to use something for 50 yrs before its proven? what about accelerated testing?

[Doctor Drivel]

Figures please? Most pro don't like the stud, and because they are dinosaurs.

Figures please?

What about real life and some figures and stop making things up.

[Matt]

Don't confuse him with something that's not on a leaflet. Dribble would think that accelerated testing was something to do with driving a plumbers van at speed around a North London council estate.

[Doctor Drivel]

Lord Hall, you are the epitome of confusion. You are the definitive FUD.

[David]

In article , Doctor Drivel writes

Well, a fair amount are Transits but there are a lot of Mercedes, Volkswagens, Renaults, Fiats and others

Was copper pipe in use for 50 yrs before its widespread use?

[Doctor Drivel]

That figures.

Figures please on pushfit. Many use plastic pipe but not the pushfit fittings.