I know this has been answered before but I plumb forgot

[Last Plumber]

Any more than any other non-barrier? I thought that was largely a myth anyway, as you get more air from valve stems etc than through the pipe wall?

My thought was that Shaun was suggesting this section only, so I don't think this can be what he meant as, if a heating system is plumbed in non-barrier, there is little point in replacing a small section, and the OP has already stated he isn't up for re-doing the whole house.

Also, is this even a heating system? Could just be supply pipe to a WC cistern for all we know...

In all honesty @Ric2013 , I have no proof if it is true or not.

It was something I was told by reps from different plastic pipe manufacturers, as well as an article I read on it years ago along with what Plumbers merchants and other Plumbers have said. This was when barrier first appeared.

I presume that there is some truth in it but can't swear by that. If you know different then fair play, I could be wrong. It does sound like ballcocks but we could also be talking about molecular sized issues! Air/ Gases V's Water??

I do not use plastic pipe as I think it is messy looking and takes all the skill out of the job. Anyone can push fit things together and do a hose pipe job and to my mind that is all it looks like. My opinion. I was working before the craze.

I realise that a lot of people use it and there are good enough reasons for that so I am not saying that 'skilled Plumbers' do not use it, that is not the same thing as saying there is little skill required to use it. I also think it allows DIY or other trades to do 'some' Plumbing with little knowledge of the job itself. This usually leads to me n thee mopping up someone else's mess.

 

[WaterTight]

And while we're on the subject, imperial copper pipe as fitted back in the day when you find it already installed is it 1/2", 3/4" etc internal bore and so the OD can vary depending on pipe wall thickness or is that incorrect? Thanks

 

[ShaunCorbs]

Correct but you will find od is pritty good, I'd can vairey

 

[WaterTight]

So if 1/2" refers to ID but only "in name" i.e. "nominal" because the ID varies but the OD is consistent (which i would assume as imperial to metric couplers exist - even in push fit - which must rely on a consistent OD) what is the OD?

I found this chart but it doesn't seem to make sense as I thought 3/4" pipe's OD was smaller than 22 hence why a 22mm fitting feels loose on it. And 22mm refers to the OD of the pipe...

Pipe Dimensions: Metric - imperial - Graphskill Ltd

 

[Last Plumber]

So if 1/2" refers to ID but only "in name" i.e. "nominal" because the ID varies but the OD is consistent (which i would assume as imperial to metric couplers exist - even in push fit - which must rely on a consistent OD) what is the OD?

I found this chart but it doesn't seem to make sense as I thought 3/4" pipe's OD was smaller than 22 hence why a 22mm fitting feels loose on it. And 22mm refers to the OD of the pipe...

Pipe Dimensions: Metric - imperial - Graphskill Ltd

That pipe dimension chart is for steel.
BSP = British Standard Pipe.
The old Copper was I.D. measurements as Shaun said.

 

[WaterTight]

This product must be not be fit for sale, strictly speaking then...?

PB / PEX Universal Pipe Insert 15mm

 

[WaterTight]

Look at me, 5am on a bank holiday Sunday posting about pipe inserts. Anyone got a spare life? I'm seem to have misplaced mine.

 

[ShaunCorbs]

Depending on the internal wall it could be too tight or too loose

 

[Welder]

All plastic pipe except MLCP (so far as I recall) is gas permeable i.e. lets air through - even barrier pipe. The barrier pipe simply lets less through. The BS (cant recall it) simply states it can let through no more a certain amount.

This is one reason why fitting something like a Spirovent will mean the need to permanently keep an eye on, and top up, system pressures when you have say UF htg installed. For some reason, here in the UK we accept leaking pipes but in places like Hong Kong they don't...

 

[Ric2013]

This product must be not be fit for sale, strictly speaking then...?

PB / PEX Universal Pipe Insert 15mm

I think it's 'universal' in that it fits BOTH kinds of pipe sold on that page of the TS catalogue, not that it fits all 15mm pipe by all manufacturers. Bit misleading...