Soil pipe and cross flow

[lostinthelight]

Hi, could someone please give me a definative answer as to whether the setup in the attached image complies with BR. I have trawled through them and am none the wiser.
thanks
litl

 

[Newboy]

Your arrangement isn't strictly compliant with building regs. guidance as the installation of "Opposed branch connection in the horizontal plane should be avoided" (Doc H page).

That said, the guidance notes are just that. In practical terms your plan will work - use an Osma 4S230. I'd be inclined to use AAV traps on the basin, bath and shower branches.

 

[bernardgreen]

There is an anti rodent flap which also reduces the problems of back to back toilets

https://mcalpineplumbing.com/wc-con...rb-1-anti-cross-flow-and-rodent-barrier-valve

 

[John D v2.0]

I would say it's compliant, that's why they make that back to back 110mm fitting. You can't run two toilets back to back into the same branch (horizontal) as you'd get someone else's turd visiting you, but into a stack it's specifically allowed as they are exactly level. Gravity is on your side.

 

[JimCrow]

A double branch is fine on a vertical soil stack.

 

[Hugh Jaleak]

Double branch in fine, I'd be wary of those wastes though, maybe better using something like this. https://www.screwfix.com/p/floplast...gclsrc=aw.ds&dclid=CO7GxOnuwdkCFcSM7Qod774I2A