Hi all - recently got some local company to install new cloak room - toilet and sink (no shower) - this involved chasing some copper pipes for radiator and cold feed to sink. They have used compression fittings buried in screed. I am not happy - no leak tests done, fittings buried under screed. All OK so far but are there any proper building regs or anything I can reference? Plumber said they did this because they could not ensure all water was drained (lowest point in the system) and they have bad experience with solder fittings at low floor level.
Obviously with the weather being so hot I have not have had heating on. I don't think they should have used compression fittings under the floor - likely when weather gets cold and I am running heating in anger thermal expansion of pipework will be an issue
Anyone got any opinions or can call out specific regulations I am missing
Thanks so much
Plumber said they did this because they could not ensure all water was drained (lowest point in the system) and they have bad experience with solder fittings at low floor level.
this has some sense to it. My friendly plumber does the same for the same reasons and I have had solder joints fail because the pipes were not dry enough
a properly made compression fitting is as good as a solder joint is it not?
Maybe tj cheers - all my googling (probably bad) says no compression fits in areas that cannot be accessed - compounded by my concern on thermal expansion! Might be fine now but in winter I have horrible thoughts of leaks....
For what it's worth I've been a DIY plumber in my own house for 20 years now. Never had a compression fitting fail.
The long and short of it is that any type of fitting can fail. If and when it does you just need to gain access and fix the issue.
I wouldn't be worrying about it personally.
Edit: Forgot to say don't worry about thermal expansion, they're designed to deal with that, what with them being used for heating and hot water systems.
all my googling (probably bad) says no compression fits in areas that cannot be accessed -
Ah - I think that is right. When my friendly plumber did it the compression fittings were accessible it was joining new to old that was compression fittings but the joins were accessible
Not at all sure if thats just best practice or regulation
Jeff cheers - I get compression fits (under flooring etc) are OK - I am talking about ones buried in screed / concrete with absolutely no easy access apart from digging up the bloomin floor! My concern is I don't belive compression fits buried (and locked in) with screed can deal with thermal expansion (let's remember coper can expand 1mm +/- in 1meter at 80 deg C!) - pretty sure all advice is never ever bury inaccessible fittings.... Just wish I had a firm reference point and clear guidance
It's not guidance, it's the law. Water Supply (Water Fittings) Regulations 1999, Schedule 2 is what you need.
7.—(1) No water fitting shall be embedded in any wall or solid floor.
Get them back and get them to do it right.
That reference is from the water regs and applies to hot and cold services which should never be buried in a floor screed unless the pipe is withdrawable or in a purpose made duct. Heating pipes can be buried but of more concern than expansion is did the protect the pipe from the screed as the cement will eat the copper.
Thermal expansion can cause problems but the runs usually have to be quite long and in my experience they usually fail on a tee piece as the branch which is obviously fixed compared to the direction of expansion movement.
They are right about soldering at low level but press fit would be a far better choice. Personally I don’t think a well made compression joint is that much of an issue but not protecting pipework from corrosion would be of concern.
Pioew are buried often because customers won’t accept surface pipework even if you point out the regulations.
Heating pipes can be buried but of more concern than expansion is did the protect the pipe from the screed as the cement will eat the copper.
I came to say exactly this. Any lime in the mix will attack copper
It may be that you have plastic, but then you wouldn't use compression apart from a few odd joints
I DIYed this sort of thing recently, a supply to an extension under the patio. I used oxy-acetylene and copper phosphore rods. It all gets so hot any water boils off long before the flux starts to go black. The working range of the rods is 715-805°C which is about 300°C higher than solder. Copper phosphore is easy to use on copper joints which melt 300°C higher but on copper-brass joints it requires care as brass melts at not much more than 100°C more than the rods. In these parts professional plumbers don't use soldered joints - it's always copper phospore.
I've used one compression joint in my house to make a spur where the fire risk with gas was too high - so far so good.
I would be more worried about the screed causing corrosion though the copper than the joint failing through expansion and contracion .
Cement based screed can be quite aggressive on copper and the modern pipes don't have a lot of wall thickness.
I would probably have gone to plastic pipe with no joins under the screed with adaptor to copper if required above ground
modern pipes don't have a lot of wall thickness.
I've found no difference when reusing half a century old pipes and modern tubes with an EN 1057 standard sticker on. Even the small tubes should be .7mm thick and bigger ones thicker. You can get different types (thicknesses) though probably only from a specialist. When I run pipes through concrete I either use a plastic sheath or foam insulation if I'm worried about frost damage or heat lost.
Don't throw old tubes away, I got 108.80e for 16kg of old tubes from the scrap metal dealer yesterday.