Can you run soil pipes over 6m if you break it with a vertical section?

[ChrisKingston]

Trying to put a new bathroom right in middle of semi-detached house, on the second floor.

It will have to be a 90degree pan connector and then a 4.5m horizontal run just to get to the external wall (can get a 10cm fall over the 4.5m), then the main soil stack is about another 2.2m and right-angled bend away. But I can put a vertical section in between the horizontal runs - say 1m or I could do 1.5m or even 2m if that would help. So the setup would be like this:

Would this work and be compliant with regs? Does the vertical section reset the 6m limit? I could fit access bends/junctions at the three joins if that would help, but would like to avoid an AAV if possible.

What length of vertical section between A and B would be best? I guess bend B will need to be well supported with clips to take the weight of falling waste and water - I thought maybe a long radius bend at B but they don't seem to do them for above-ground plastic 110mm drainage.

Should the new vertical section A-B continue up and be vented at the top? Or is the ventilation in the main soil stack enough?

Thanks

 

[denso13]

Not really. Put in a vent upwards at "A" and that will solve it.

 

[ChrisKingston]

Like so? What length of vertical A-B do you think?

 

[denso13]

 

[ChrisKingston]

Thanks. And the vertical section does make a run that long with two bends ok?

 

[denso13]

Yes, that's fine.

 

[ChrisKingston]

Been up and looked and getting a vent vertically on to that branch would be a pain to get 900mm above nearest window, it would have to stick up about 1500mm unsupported above gable roof.

But I could run the vent at 45degrees up towards the other stack. In that case is there any point keeping the two separate? Or could I join the second one back in to the main stack to share its vent? It would be well above all the soil connections.

Something like this:

 

[denso13]

Could do, or just put an AAV at "A".