Does a Durgo type valve need a soil vent pipe as well

[Penelopejean]

Hello there,
Please could I have confirmation from anyone or even a plumber that knows how to interpret Part H. I have read and re-read some Q&A's on here but would like to know if possible what is correct. I wasn't around when our building inspector came and he hasn't called me back with my query today.
We are having an en-suite fitted in our detached 1960's bungalow. The plumber says he is fitting a Durgo valve to the WC. The existing bathroom, up stream, definitely does not have an existing soil vent pipe to air anywhere and I don't think the inspector was aware of that. Where it is no-one knows. Can he fit the durgo valve or does he have to fit a vent pipe up through the roof somewhere? I have read that when a SVP is fitted it should be on the first one in the run ie in the existing bathroom. Any advice will be well received please.
Thanks

 

[Hugh Jaleak]

Ideally the head (the highest point) of the drain should be ventilated. If you haven't got a vent on the drains on your property, it certainly wont hurt to provide one, but I dont think it'll be an unmitigated disaster either, without a vent. Ground floor WC's etc can connect directly to the drain provided the drain isn't more than 1.3m deep, and again, I doubt this would be an issue either.

If you dont currently experience any issues with smells, or traps being pulled then let your plumber carry on, the B.C.O. seems happy too, so all is good.

 

[Penelopejean]

Thanks Hugh. That's a really clear answer and what I wanted to hear really. The plumber did mention something about 1.3m but I thought he meant horizontally not vertically. I'd rather not have a hole made in the roof if not necessary so many thanks for that.