ProDave Posted January 7, 2017 Share Posted January 7, 2017 I have been putting up the stud walls that define the bathroom and en-suite rooms. That means having a think about the layout of both rooms so I know everything will fit and the doors are in the right place etc. At the same time I have been thinking about how I will plumb all the wastes, and have hit a problem. I can't seem to find the waste fitting that I will need. I will try do describe it: Imagine the 110mm waste stack coming up from the room below (the utility room) right in the corner. as you stand looking at that corner, I want one 110mm pipe to branch left along the front wall of the house to serve one toilet, and I want another 110mm pipe to branch off to the right, along the side wall of the house to serve the other toilet. So I need a 110mm branch that will take TWO 110mm pipes in at 90 degrees to each other. I can't find one. I have seen a double branch with inputs 180 degrees apart, but not 90 degrees apart. It has to be all in one fitting as I want both branches to travel to their respective WC's within the posi joists, so stacking two branches one above the other won't work. Any ideas? Link to comment Share on other sites More sharing options...
joe90 Posted January 7, 2017 Share Posted January 7, 2017 I have also been looking at fittings and confess to not seeing one of these but I did come across plumbing regs that stipulate branches not being opposite one another otherwise the two toilets could " swop contents". My BIL used to live in a house split by his dad ( a bodge builder) for him and his sister many years ago and they had back to back toilets and they used to swop contents a lot. Link to comment Share on other sites More sharing options...
ProDave Posted January 7, 2017 Author Share Posted January 7, 2017 I can't see that happening unless the stack is not well ventilated. One toilet will be close to the branch, the other about 3 metres away. the two branches will run within the posi joists then turn 90 degrees to go up through the floor to each pan. What I want to avoid is the two toilets sharing a common horizontal pipe run. that's why I want them to branch at the stack. Link to comment Share on other sites More sharing options...
Nickfromwales Posted January 7, 2017 Share Posted January 7, 2017 You mean a corner branch ? http://m.ebay.co.uk/itm/111911500778?_mwBanner=1 1 Link to comment Share on other sites More sharing options...
ProDave Posted January 7, 2017 Author Share Posted January 7, 2017 That's exactly what I mean. as usual it's a case of knowing the correct name for what to search for. I had a feeling it must exist, I could see no reason why someone could not make one, but I have never seen one, and they are not in the common places like TP, Screweys, toolstation unfortunately, that one "does not post to Scottish Highland" But I see several people selling the same thing, so I am sure one of them will post it here. Question. Looking at that, it appears both branches are push fit with a ring seal, but why are the details of the two branches different? Link to comment Share on other sites More sharing options...
Nickfromwales Posted January 7, 2017 Share Posted January 7, 2017 Fack knows Check out this bad boy. Come out of this with two M&F bends to rectify back to horizontal and then you'll have no issues with what Joe mentioned ( which is with merit I assure you ). 1 Link to comment Share on other sites More sharing options...
PeterW Posted January 7, 2017 Share Posted January 7, 2017 5 minutes ago, ProDave said: Question. Looking at that, it appears both branches are push fit with a ring seal, but why are the details of the two branches different? Tooling ... basically to injection mould that you need one of the branches to be smooth as you need to eject the moulding hence the design. 1 Link to comment Share on other sites More sharing options...
Nickfromwales Posted January 7, 2017 Share Posted January 7, 2017 I think these would do it. Make the branch lower than the soil so you deffo don't get any cross flow. TBH, that issue is more problematic with a 180o offset rather than a corner branch, but if it was me ( and more importantly you have the room / distance ) I'd still endeavour to 45 into it to make a 'sump' at the branch. Link to comment Share on other sites More sharing options...
Nickfromwales Posted January 7, 2017 Share Posted January 7, 2017 3 minutes ago, PeterW said: Tooling ... basically to injection mould that you need one of the branches to be smooth as you need to eject the moulding hence the design. I was JUST about to say that ? Link to comment Share on other sites More sharing options...
Nickfromwales Posted January 7, 2017 Share Posted January 7, 2017 Link to comment Share on other sites More sharing options...
ProDave Posted January 7, 2017 Author Share Posted January 7, 2017 Well I have just ordered one of Nick's first link, but from a different ebay seller. And it was a bit cheaper. I can see the "swapping contents" issue if you just branch at pan outlet level, and have two very short runs to the two pans, but I am branching under the floor, 2 runs under the floor then each turning up and through the floor to it's respective pan. I HOPE I won't be starting a "swapping contents" thread in the future when it eventually all goes live. Link to comment Share on other sites More sharing options...
joe90 Posted January 7, 2017 Share Posted January 7, 2017 Nicks a star ain't he. ? Link to comment Share on other sites More sharing options...
Nickfromwales Posted January 7, 2017 Share Posted January 7, 2017 Aw.....Shucks "That's 350 quid, plus vat, plus materials, plus consumables, plus fitting, plus labour". Link to comment Share on other sites More sharing options...
ProDave Posted January 7, 2017 Author Share Posted January 7, 2017 My drawing skills are not as good as Nick, but this is what I want to achieve: the left hand branch follows the front of the house (in between two joists) and then turns 90 degrees up through the floor to pan 1. the right hand branch travels a short distance, through one or possibly two posi joists, before turning 90 degrees to run between joists, then turning up 90 degrees to go up to pan 2 in the other bathroom adjacent. I can't see there being a "swapping incident" Link to comment Share on other sites More sharing options...
Nickfromwales Posted January 7, 2017 Share Posted January 7, 2017 25 minutes ago, ProDave said: I can see the "swapping contents" issue if you just branch at pan outlet level, and have two very short runs to the two pans, but I am branching under the floor, 2 runs under the floor then each turning up and through the floor to it's respective pan. That'll be fine. And unless the invert is in excess of 1300mm, you really don't need anything for air admittance at the pans, just a vent or AAV at the top of the branch. Link to comment Share on other sites More sharing options...
joe90 Posted January 7, 2017 Share Posted January 7, 2017 No I agree, their branches ran straight into the back of the toilet not from below floor level. Whew! Link to comment Share on other sites More sharing options...
Nickfromwales Posted January 7, 2017 Share Posted January 7, 2017 Any reason not to ? Link to comment Share on other sites More sharing options...
ProDave Posted January 7, 2017 Author Share Posted January 7, 2017 I thought if I did that, then when you flush pan 2 it might suck pan 1's trap dry unless you have another AAV. I thought it best to not have any shared horizontal runs? Link to comment Share on other sites More sharing options...
ProDave Posted January 7, 2017 Author Share Posted January 7, 2017 Another revision, would moving the vent cause an issue: Taking the vent straight up, would mean more "boxing in" If instead, I made the turn to pan 2 a branch, that could then continue and turn upwards to the vent through a bit that is already being boxed in. Would that cause issues? Link to comment Share on other sites More sharing options...
Nickfromwales Posted January 7, 2017 Share Posted January 7, 2017 9 hours ago, ProDave said: I thought if I did that, then when you flush pan 2 it might suck pan 1's trap dry unless you have another AAV. I thought it best to not have any shared horizontal runs? It would never happen. As soon as the slug of water has cleared the first bend you'll get what's called an "air break". That means the water cannot physically occupy the whole diameter of the pipe and therefore cannot create a vacuum. Vacuum issues are typically only associated with vertical drops after 1m fall or more. I believe ( iirc ) BR are happy with a vertical drop ( invert ) of 1300mm before they require an AAV. The T option ( Y-branch ) will work perfectly well. ? Link to comment Share on other sites More sharing options...
Nickfromwales Posted January 7, 2017 Share Posted January 7, 2017 16 minutes ago, ProDave said: Another revision, would moving the vent cause an issue: Taking the vent straight up, would mean more "boxing in" If instead, I made the turn to pan 2 a branch, that could then continue and turn upwards to the vent through a bit that is already being boxed in. Would that cause issues? That would work. As long as air can get to the vertically falling slug of water then vacuum deficit would be taken care of. No probs with that arrangement, as long as the branch is a Y with a 45 in it to rectify back to 90o. Essentially your then sending the 'products of nourishment' from pan 2 towards the corner branch, rather than stalling at a regular branch and then relying on the fall ( from the vent ) to direct the flow. 1 Link to comment Share on other sites More sharing options...
ProDave Posted January 8, 2017 Author Share Posted January 8, 2017 So, following on from this, I have had a day mostly of thinking and planning things, rather than doing things (always a bad move) which brings me onto my next "whacky plumbing idea" As well as connecting the aforementioned two WC pans, I have some showers and basin's to connect, and I want to keep it all within the width of the posi joists. in the last house I used one of these http://www.ebay.co.uk/itm/FLOPLAST-110mm-Ring-Seal-Single-Boss-Soil-Manifold-Grey-/182280025263?hash=item2a70bc74af:g:R3EAAOSwmLlX142C The hopper was placed in the stack before the branch to the WC's. I could do that in the last house because there was a large boxed in space in the room below and the hopper sat down in that boxed in space. But this time I don't want to do that, it must all go in the joist space, and there is not room for a hopper and the branch. So what if I used one of those hoppers in one of the horizontal runs of pipe? the 110mm bit would just pass straight through, and as long as the smaller inlets were above the centreline of the 110mm pipe I can see no reason why it would not work? Give me a reason why not please? Link to comment Share on other sites More sharing options...
Nickfromwales Posted January 8, 2017 Share Posted January 8, 2017 59 minutes ago, ProDave said: had a day mostly of thinking and planning things, rather than doing things (always a bad move) which brings me onto my next "whacky plumbing idea" Never EVER is that a bad move. Beats the shit out of doing things twice at double the cost 59 minutes ago, ProDave said: what if I used one of those hoppers in one of the horizontal runs of pipe? the 110mm bit would just pass straight through, and as long as the smaller inlets were above the centreline of the 110mm pipe I can see no reason why it would not work? Give me a reason why not please? If you look at the fitting, it clearly has a line dissecting the two halves, and also a number of holes where integral moulded clips spring into to hold the two together. That tells me that this is DEFFO not designed to be used other than with gravity as its friend. Aside from that, I'd just never even consider using that in such an orientation, just from my gut feeling that it would end badly. I'd recommend fitting these and making the waste off with solvent NOT push fit wherever possible. You can happily run a single 2" ( 50mm ) from each bathroom with everything combined. Eg bath and basin combined, or shower and basin combined, as long as the pipe work is of course 50mm all the way from the T to the boss. Air admittance traps on the basins like these anti syphon ones will take care of any issues with the drop from the basin to the invert ( where it meets the soil under the floor ). Link to comment Share on other sites More sharing options...
ProDave Posted January 8, 2017 Author Share Posted January 8, 2017 I had in mind the alternative as a row of strap on boss's, Is it okay to go into the side of a run or does it have to go in the top? Re combining several items into one pipe. I would hapilly combine the two (back to back) showers, or the two basins, but I once had a very bad experience with a basin sharing the same run as a shower. Not quite "swapping contents" Water would come up the shower trap into the shower every time the basin was emptied. Not wishing to repeat that. Link to comment Share on other sites More sharing options...
Nickfromwales Posted January 9, 2017 Share Posted January 9, 2017 With 50mm pipe that would simply never happen, I've got scores of private jobs done that way and not one complaint. They're all turbo wastes too so have very high l/per/min discharge capacity ( so 1 1-2" ( 40mm ) waste would not suffice, even on its own tbh for anything other than a very very short run to soil ). NEVER tee the two showers together, these must go on their own runs. Combining those runs with basins is fine, but never two showers on the same pipe afaic. Teeing a bath into a run with a shower and basin is pushing it, but if you have sufficient falls between each item or a good continuous fall from end to end, even that will work with an 'all 50mm' run to soil. Tee off the 50mm with 50mm pipe for the shower, and run 50mm as far as you can before reducing to 40mm, and for the basin, reduce at the 50mm tee to 40mm and run 40 as far as the vertical rise to the basin BEFORE reducing to 1 1/4" ( 32mm ) which will guarantee you never get anything coming out of the shower. If reducing to 32mm at the vertical rise, do so with a 40mm elbow with a 32mm reducer in the top of it. The sooner you upsize the pipe, the sooner you get the 'air break'. Im not a fan of strap on bosses tbh. The ones I linked are all solvent for the wastes ( if you select the one you buy accordingly and ask for the solvent inserts as required ) and push fit on the 110mm side so are very forgiving, easy to fit and no dodgy huge holes to drill and de-burr and then try to line the boss up spot on to. Fwiw I use SOBosses but only where I can get at them, or, if I've no other choice ( like on an existing / retrofit where I cannot get to the pipe to alter it ) but then I want the boss cut into the top dead centre of the pipe. Inwould never design SOBosses into a job where all the connections are under the boards / inaccessible, as the ones I linked are just far better, easier to fit, and far more reliable IMHO 1 Link to comment Share on other sites More sharing options...
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