Why does soil vent pipe need to be 110mm?

[xenonflx]

Hi Everyone,

First post here!
I'm trying to find out why the vent part (above all sinks, toilets etc) of the soil stack needs to be 110mm? Surely this part of the pipe should only carry gasses (albeit not very nice ones) and as long as it gets out of the property it's still serving it's purpose. Would using, say, 40mm pipe be acceptable in terms of regulations?

Thanks in advance.

 

[Softus]

It doesn't have to be 110mm, but you won't have any trouble with your BCO if you use 110mm, because the path (of least resistance) that the 'gas' will take will, unequivocally, be the vent.

Ask your LABC - mine has previously let me use 50mm where circumstances were conducive.

 

[xenonflx]

Thanks for the reply Softus. I'll give them a call

 

[Softus]

You're welcome.

Please let us know the outcome - the knowledge will benefit all forum members.