Soil stack connections at 90 degrees?

[minos]

Hi,
I am about to start the installation of an ensuite bathroom in my loft conversion, I have a soil pipe in the corner of the new ensuite into which I want to connect a W.C. waste and a combined Bath/ sink waste at 90 degrees to each other.

Am I correct in thinking from reading the relevant building regs that I can connect "non opposing wastes" on the same level?
Can I use a 92.5 degree branch fitting and a 40mm waste for bath/sink connected with to the boss outlet ?
I aim to use Hepvo self sealing valves on both the bath/sink.
Many thanks in advance for your help,

 

[Hugh Jaleak]

Dont see that being a problem, the waste from the W.C. shouldnt reach the boss connection anyway unless the stack blocks! Alternative is to use a manifold, then the branch to W.C.

 

[rojaca]

My interpretaion of the diagrams is that as long as the centre lines are at the same height then opposing branches are acceptable. If you meanthe bosses that cconnect on at 90 degrees to the wc branch as you look down the axis of the pipe (top to bottom as it were) then there is no restriction on position of the boss as long as it remains at 90degrees to the branch.

eg if imagine soil stack as clock face looking down. wc branch at 12 o clock, waste brances can be positioned anywhere between 9-3 o clock without worrying about cross flow