graduate_owner":33k0eg97 said:
Eric - have you found problems with plastic fittings? I have used these in places where they can't be seen because they are a bit bulky and ugly, but I thought they were reliable.
Qualified 'yes' to that: I used a bit of 22mm (JGuest) as temporary piping while we were reorganising heating and hot water in the house. It stayed installed for about 6 years, and when I finally removed the last bits, the couplers had discoloured a lot - from white to quite yellow, even though they weren't exposed to any UV, but they were in an airing cupboard.
That's possibly the start of depolymerisation - you see the same effect in PC equipment that's moulded in polystyrene and ABS. Left longer, the surface starts to break up on the yellowed stuff. If it had been outside, I'd have blamed sunlight, but it was in a dark cupboard.
I also had a flexible coupling to a kitchen tap swell up like a balloon and pinhole. It was held in place by the stainless braid around it, so the leak could have been a lot worse, but when I fixed it, the interior of the pipe had a cheese-like consistency - you could easily scrape it away with the end of a scrwdriver. It was a hot feed, in a hard water area. I've never used those flexible couplers since that, even though they often come with the taps.
Finally there's the commercial landlord view: a good friend retired a year or so ago from being a clerk of works for a (big) local housing association. His job was being their eyes and ears on newbuild sites. They allow grey plastic, but they will not allow concealed joints anywhere, under any circumstances. The runs have to be uninterrupted when they're in walls & floors.
So I always do copper. If access is really tricky, I drop to 10mm or 8mm, for taps as well as radiators.
Most modern taps (apart from old style bath taps) are restricted inside so they have less area than 10mm pipe anyway. I guarantee that you wouldn't be able to tell which is 10mm and which is 15mm in our place. The kitchen tap (10mm, ceramic discs)) is so powerful that it bends against the stainless steel surround if you put both sides on full at the same time. On that, both hot and cold are limited to nominally 3bar (hot is probably 4bar at the bottom of the house).
I'm probably just being paranoid, but, unusually for me, I made a bad soldered joint in a radiator pipe recently. It was only dripping about once every 10 secs, and only overnight, but it made a horrible mess of the ceiling below. The Domestic Controller was surprisingly cool about the whole thing.
And the Trevi Fountain: - a friend was redoing his bathroom. I'd offered to help but it was declined, as plastic is 'so much cheaper'.
Genuinely coincidentally, I happened to drop in whilst his mate from next door ("he's a plumber") was finishing off the pipework in grey plastic (all T-joints under the floor). My friend was assisting. Before putting the boards back they decided to test it out by turning the supply back on...
... six different fittings leaking simultaneously (a couple actually blew apart) can make a lot of mess in a very short time. OK, I know they weren't mated properly, obviously, but they are supposed to be easy, and this chap was supposed to have done it before, lots.
I made my excuses and left. Otherwise, I didn't say a word.
