Waste and soil pipes into stack

[Rzzrmeanr]

Hi,

I'm installing a new bathroom, and I have a toilet waste branch pipe and shower waste branch connecting to the main stack very close to each other i.e. the toilet waste will connect to the stack about 10cm above the shower waste. Both branches enter the stack on the same side. Is this acceptable for building regs?

According to the building regs H, you must leave a 20cm no connection zone on a stack below an incoming branch pipe, so that it doesnt cross-contaminate any branch pipes below it.

However, when looking up branch connectors, i notice you can get fittings which have all 3 (110mm, 40, 32) next to each other coming in at different angles (for example FloPlast SP190 92.5° Branch Black 110mm ) . Surely you'd end up with cross-flow using these?

I'm not quite clear when the 20cm no connection zone needs to be established.



I've attached a pic too. thanks
Rory

 

[oz-plumber]

Looking at the pic, I would say you would need to jackhammer the concrete, put a junction in so that the shower waste will drop vertically into the the new branch.
This may give you enough clearance in the stack for the WC drain connection.

If not the WC drain will have to come off the the lowered junction with the shower waste going into the top of that drain and continuing the drain to the WC