Long shower waste run - can I avoid a stub stack?

[maznaz]

Hi there. I'm renovating a bathroom entirely with the proposed layout. The joists are doubled around the bath so I can't really change the layout much at this stage. The joists run left to right across the room. My issue is the existing soil stack (blue blob) necessitates a shower waste run that exceeds the permitted distance for any size pipe I can use. My BCO has suggested we install a secondary stack (green blob) but there's quite a lot involved in that, either teeing into the soil before it hits the sewer, or paying a substantial amount to go direct into the sewer. This is a first floor bathroom and the room below is a kitchen but all in progress right now so digging etc is okay.

 

Is there any way I can run that waste for the required distance, which is about 5 metres, using an air admittance valve or something? The building control officer was pretty sure I needed another stack but it does seem overkill for one shower.

 

Thanks for thoughts!

[Temp]

@maznaz  See Approved Doc H below..

 

Para 1.20... Says an AAV is OK. 

Para 1.22... Says it must be within 750mm of the trap. Should be accessible in case of maintenance.

 

I'd use 50mm pipe.

 

 

Edited May 14 by Temp

[Nickfromwales]

5m in 50mm pipe will be fine. To appease the BCO you just need to demonstrate it working afterwards, they shouldn’t really be too bothered about anything after the 110mm pipework / vents etc.

No need for an AAV unless the pipework drops vertically a good distance before meeting the stack.

[maznaz]

Thanks both. I'll have another chat with him.