Urgent Help Required - Mains Drains layout on new build

[theoldun]

Okay. Soil pipe left hand side of building. Take this one up through roof as head of run and vent to air. Run drain parallel to left hand external wall and out of flank wall and form 90degree IC in line with IC (B&A).
Soil stack on top wall of drawing (assume) flank wall. Drop this into IC (B) all as your drawing. You could make this a stub stack with durgo vale at first floor level, but seeing as your trying to fit 8 bathrooms into three stacks would suggest that you also take this out to air.
IC (B) will run into IC (A) all as drawing.
External soil stack bottom of drawing, suggest you also take up to air. Drain run parallel to external wall to stop in line with IC (C ). Form 90 degree IC at this point going directly to IC (A). The IC (C ) as shown on your drawing has now been done away with.
Make sure foundation concrete is finished 450mm below finished ground level so that parallel connection runs can sit on top of founds. If we had lengths of runs could give you falls and invert levels. You are not stuck with a 1to40 fall, you can go down to 1to80.
You will need a fairy god mother of a plumber to fit 8 bathrooms into three soil stacks. Would be curious to see inside layout.
Hope this helps. Any questions, then ask.
Regards olddun

 

[tim00]

My suggestion to the OP is that if this is a self-build, then to stop right now, and call in a professional for at least a heads-up bit of advice. Like learning to drive, when learning to build, if you are in a hurry then you are wrong. And BCO will confirm it.

If that is the best plan you can come up with, with no indication of internal layout, as suggested above, then you are in need of a professional on site and the production of a professional drawing.