I'm about to re-jig a bathroom where the bath waste is piped in solvent weld pipe which is 43mm in diameter, and the fittings say 43mm.
However, no-one seems to sell 43mm waste pipe - it is all listed as
40mm! Looking for clues via Google seems to suggest that the OD of 40mm solvent weld pipe IS 43mm (presumably with the ID being 40mm)- but I cannot find an explicit statement to this effect.
Can anyone re-assure me that, if I buy some "40mm" pipe and fittings, they will marry up ok with the existing 43mm (actual) pipe?
It's always been a bit of a puzzle to me why the size of the pipes that go, say around the loo cistern, is always slightly different to the generality of plumbing pipes and fittings. As a result there is often a bit of a bodge found where service attaches to fitting. Why they can't just have one standard set of sizes...
No, but if you buy 40mm *solvent weld* (ABS or PVC) pipe and fittings they will marry up with the existing pipe. If you buy *push-fit* (Polypropylene
- PP) pipe and fittings they won't match as they're smaller diameter. If you need to join one system to another you can use compression fittings, special push-fit couplers which fit the larger solvent-weld pipe, or an 'expansion joint' which is a coupler with one solvent weld socket and one push-fit socket. I've found the latter at B&Q, but the special push-fit/push-fit couplers only at BES (and maybe some other 'proper' plumbers' merchants).
Are you absolutely sure? The reason I ask is this: In the Screwfix catalogue there are some FloPlast ABS solvent weld pipes and fittings which are stated to comply with BS EN 1455-1:2000. I've just looked up the standard, and that appears to say that 40mm pipe has an OD of 40mm (max 40.3)- which *wouldn't* be compatible with the existing pipe, which definitely measures 43mm.
I found recently that you can't even rely on overflow pipe being the same size from the same manufacturer. I was recently re-plumbing the bodge I'd made whem moving the loft tank several (about 15) years ago, and was extending in the same make of pipe. One was 21.5mm and the other 22mm. Both labelled along their length as marley overflow. Much cussing and swearing (Sunday, late afternoon of course) and another (but better) bodge job resulted.
and yet BES.co.uk has:- "Solvent weld waste system to BS 5255, kitemarked, (EN1455-1). ABS. The nominal sizes of the pipe (32, 40 and 50 mm) refer to the approximate inside diameters of the pipe."
I'm measuring the OUTSIDE diameter of the pipe. [I didn't have my vernier calipers with me at the time, and so used an adjustable spanner and tape-rule - but this was certainly good enough to tell the difference between 40mm and 43mm.] The fittings had 43mm embossed on them.
This would certainly stack up with having an ID of 40 - but the BES information appears to be at variance with what the standard itself says. Maybe I'd better have another look at the standard in case I've misread it.
I agree with information from the other replies. I've only known one size of solvent weld and its fittings/pipes seem to be interchangeable across manufacturers. If you are still not convinced, buy all new solvent weld and then compression couplers to fit to the old stuff were it goes into the wall or floor. The best compression fittings are MacAlpine rather than the cheapo generic stuff. You'll have to go into a merchant to get those.
If the OP can wait until later today, I've got some 40mm solvent weld work to do. I'll measure mine then. Have a feeling all my "40mm" is marked 43mm OD so that's probably correct and that spans at least Marley and Floplast if not another maker too.
As long as it is a good fit in the joint and both parts or uPVC and/or ABS and they fit snugly, they can be welded with teh appropriate cement. For everything else, there's universal compression joints which are very forgiving (eg you'll find this type of joint on most modern U traps so you can shove any pipe of the same nominal size on.
Went to a PM today, and they had some fittings marked BS EN 1566 (rather than 1455) and, embossed on them, it said "40mm (OD 43mm)" and, for the smaller size "32mm (OD 36mm)" - both of which look as if they should fit. Yippee!
HOWEVER, they're made of PVC rather than ABS. Early on in this thread, someone said "make sure you get ABS". Does it really matter? Can I mix and match? [Some solvent/adhesive claims to be ok for either]. How do I tell which sort the existing stuff is?
I asked the bloke at the PM whether they had equivalent fittings in ABS, and he said "No".
So, just supposing the old stuff is ABS, what happens if I try to weld a bit of old ABS pipe into a new PVC fitting?
If I *can't* do that, I'll need to replace a lot more stuff - including bath and basin traps - with new, and just have a single connection between old and new using a compression fitting - or maybe something like Screwfix 81383. [The universal compression coupler (11980) is much cheaper - but it doesn't say what range of sizes it accommodates].
I would much rather use solvent weld on this principal old to new joint because it will shortly become inaccessible - and it's just above someone else's ceiling, so I can't afford any leaks!
It's fine AFAIK. The Floplast SC250 isn't just solvent - it is very loaded with filler in solution (ie it is very gloopy). The filler is compatible with ABS and uPVC. Mostly I would expect your join interface to be uPVC|filler|ABS
It's quite good at gap filling if your fittings were sloppy (couple of mine were) and also, if your fittings are tight dryfitted, they go together easily once this stuff is on.
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