soil vent pipe connections

[george765]

Hi,
I have an existing steal soil vent pipe on outside of my house (vertical)with a 't' connection, and a bend turning through the wall to the upstairs w.c.
I plan to install another w.c. in the adjacent bedroom and will need to use the same sv pipe (which i plan to replace with plastic) the connection will come from the other side of the sv pipe.
I think I read somewhere that the w.c.connections must not be connected opposite or close to each other on the sv pipe (for obvious reasons).
The job will be under building control and I am presently doing the plans.
Can anyone tell me the current regulations in this situation, i.e. what the b/I will be happy with ?
many thanks, George

 

[seco services]

You can connect 2 wc's directly opposite each other as the design of the connection is angled so flow drops downwards not across.

This is where you can't have a connection opposite in the shaded area, which is 200mm top to bottom.
Even that small boss on the rh side is ok to use as it's not fully in the shaded area and above the line of flow.

 

[george765]

Thanks !
Really helpfull reply. I can now carry on drawing.
cheers,
George