Urinals - How to fit

I'm looking to replace the leaking plastic pipework from an install done "professionally" a few years ago. At the time of the install one of the urinals was cracked and I have the replacement. I have also bought new wastes am now ready. (Note: This is a charity-owned hall so cost an issue)

Not the most pleasant job and I'm intending to start from scratch i.e. replacing all the plastic lock stock and barrel. Here is the current (leaky) install:



As you can see it is a mixture of 40mm compression traps and then switches to 50mm.

I'm going to cut the soil pipe down to floor level. As a DIY'er I've never used solvent weld before and never used 50mm pipe.

I think I understand why SW would be a good idea in terms of rigidity.

Is there a reason to use 50mm or can I use 40mm all the way to the vertical? I can then use one of these -

https://www.screwfix.com/p/floplast-solvent-weld-reducing-coupler-55-x-43mm-white/65568

- to join to a 50mm offcut to reuse the existing seal. The idea of using three individual "reducers" seems a little expensive and redundant and extra jointing.

Regards

Tet

Nope, keep it at 50mm after the joints, as all the urinals will be flushed at the same time, it's always best to oversize the waste pipe where there's more than one connection on the run.

SW is more permanent and the best approach, especially in a commercial setting.

Madrab said:

Nope, keep it at 50mm after the joints, as all the urinals will be flushed at the same time, it's always best to oversize the waste pipe where there's more than one connection on the run.

SW is more permanent and the best approach, especially in a commercial setting.

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Thanks for the reply, Rob.

Can you tell me where I might find the adaptor to connect 40mm SW to the 50mm tee? Everything else I can find on TS and Screwfix

The reducer you linked to (55-43mm) is the one you need, these are for 50mm and 40mm pipe size but the OD size is 55mm and 43mm.

Tetrarch said:

Can you tell me where I might find the adaptor to connect 40mm SW to the 50mm tee?

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The one you linked to earlier, https://www.screwfix.com/p/floplast-solvent-weld-reducing-coupler-55-x-43mm-white/65568, will fit in the 50mm tee and take 40mm pipe.

Urinal bowl is probably hanging on a bracket, lift it up and away from the wall and I think it should lift off. (Isolate water supply to cistern and undo pipework first obviously!) They're not the most pleasant of things to work on, and scale is always an issue, (as you may find out when you dismantle the waste pipework...)

When fitting the new pipework I'd fit 50mm Tees instead of the bends where I've circled, and fit an access plug in the unused socked to enable future cleaning as required. I also prefer to fit P or S traps as opposed to Bottle traps on Urinals', simply to allow full effect of the flush to wash the pipework through.


I wouldn't cut the 110mm pipe too low down, if anything goes wrong, you'll be digging the floor up to deal with it. Instead, cut down a bit lower, fit a 110mm coupling, (you must chamfer the cut edge before pushing the coupling on), and them a 110mm to 50mm waste adaptor to take your waste pipe. I'd be wary of reusing the existing reducer, it may not seal very well again once disturbed.

Working with Solvent weld is easy enough, but you only get a few seconds to get the joint right before it sets, assemble dry and only glue when you're 100% happy. A lot of us put a pencil mark across the socket onto the pipe to mark the position, then glue as it gives you a mark for the correct position.

Hugh Jaleak said:

When fitting the new pipework I'd fit 50mm Tees instead of the bends where I've circled, and fit an access plug in the unused socked to enable future cleaning as required. I also prefer to fit P or S traps as opposed to Bottle traps on Urinals', simply to allow full effect of the flush to wash the pipework through.
View attachment 198954

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I'll take that advice on the traps and access

Hugh Jaleak said:

I wouldn't cut the 110mm pipe too low down, if anything goes wrong, you'll be digging the floor up to deal with it. Instead, cut down a bit lower, fit a 110mm coupling, (you must chamfer the cut edge before pushing the coupling on), and them a 110mm to 50mm waste adaptor to take your waste pipe. I'd be wary of reusing the existing reducer, it may not seal very well again once disturbed.

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That rubber seal slides up the 50mm relatively easily, but I'll cut the 110 about an inch off the floor. Pre urinals it was a trench and it goes into a clay pipe that I did the demo for and reinstall pre-tiling.

Hugh Jaleak said:

Working with Solvent weld is easy enough, but you only get a few seconds to get the joint right before it sets, assemble dry and only glue when you're 100% happy. A lot of us put a pencil mark across the socket onto the pipe to mark the position, then glue as it gives you a mark for the correct position.

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That pencil mark is genius and so simple.

Thanks for all the advice. Pics to follow upon completion

Regards

Tet

Use a sheet of paper...wrap it around the pipe and mark it.
Cut the pipe rotating as you go..then you'll get perfect square cuts rather than random diagonal cuts and joints not lining up.
Consider using the proper pipe cleaner before solvent welding.