Waste system on urinals

[bster]

I am sorting a job out for a local company.

They complain that the urinals are blocking,

Only 2 urinals with a 32mm pipe work tee'd together between each other with a 'cross' tee, then straight through the wall to drain, all in 32mm pushfit waste on a 2.5m run.

I'm going to replace all pipework with 40 or 50mm ABS, What are the regs?
(i know a range of urinals should be done in 50mm but my head is saying 40mm will be fine).

one more thing - the urinals are on bottle traps - is this correct?

and one other one more thing - anti tamper TRV's and l\s valves - where to buy?

 

[Biggles..]

We used to do 50mm solvent with 40mm bottle traps teed in.50-40mm internal reducer on th 50mm tees.last tee would have a screw cap connected to it as well for clearing out. That was for a brewary maintenance firm though.

 

[bab]

I have the misfortune to have lots of experiance on this matter. When ever multiple conections are made they must all drop into 50mm tee's .I allways use solvet weld with a cleaning eye at every posible point. Best using mc Alpine 32mm Deep seal anti-vac P traps. Biggest fault for blocking is lack of flushing. regs were every 20mins.To save water a cisermiser with infa red trip is good. if urine is left standing in the trap it scales up to hard crystal type rock that a hard to remove,usally have to just keep replacing traps. The problem with push fit is it easy for it to sag, hold water then clog. good fall helps a lot. Can u replace the waste to upgrade to 40mm

 

[bster]

So 50mm the best way forward then, even though its only feed by 2 urinals?

Is it not better to use a self cleaning trap (s or p)?

and thanks for the help!