Im working in a pub (UK) and they are having probs with drainage. I no what the prob is as it goes from bottle trap to 32mm couple of bends then into a 50mm pipe that serves all four. From there a 90* thro wall then into an external 40mm pipe. Obviously the external 40mm is most of the prob, but what are the specs on a four bowl urinal set up, traps and ideal pipe sizes please! Many thanks. Lee willo

Hi Lee

I'd like to see a 3" line feed all 4 urinals....branch off 2" to each or even use a double sanitary tee fitting to pick up 2 at a time, but they would drain into 3" pipe, if possible.

In terms of code requirement I'd have to tell you to contact your local plumbing inspector as our codes will definitely be different than yours (USA VS UK).

What kind of pipe(s) are we talking about? If you have dissimilar metals (copper into galvanized, for example) then you can be sure this junction between the two metals will be a problem area.

Back to you...

Mark

Sorry, I should have been clearer! There are 4 x urinal bowls, each emptying into a bottle trap ( is that adequate ) with 32mm connections, thro 2 90* bends then reduced into a 50mm waste. This is continued x 4, all expiring into the 50mm waste pipe. Then thro a solid wall using 2 x 90* bends, then outside, but it then goes into a 40mm pipe for 3m then into the main stench pipe using a strap on boss. All waste pipe work is in plastic! My question is two fold, will 40mm from the bottle, to 50mm communal, then to 50mm external be sufficient to carry max flow? Secondly is a bottle trap the correct fitting for a urinal!