Window near soil pipe

[Entropy]

Hi there, I am looking at a loft conversion with Velux style windows in the roof. I have come across the issue of the soil pipe needs to be more than 3m from any opening. After looking at Part H I wondered if there was an accepted view regarding non opening windows being within 3m of the stack, is it possible or do Building Control still view it as an opening?

Thanks

 

[John D v2.0]

It's not the soil pipe that's a concern it's the vent at the top. Just make sure the vent is 900mm above the top of the window.

 

[EntropyUK]

That's the problem. The roof is no very high 2.5m internal with the purlin top edge being 1200mm above the floor. So to be 900mm above window would put the soil pipe above the ridge line.

 

[Alastairreid]

https://www.floplast.co.uk/article/external-air-admittance-valves

 

[EntropyUK]

https://www.floplast.co.uk/article/external-air-admittance-valves

I see what you are saying but this would cap the vent pipe so I don't see where the open ventilation would be that is required by the regs.

 

[Alastairreid]

Durgo Valve in a single dwelling with one vent pipe, perhaps if a new roof window is being fitted, an extension built or some other valid reason why you can't have an open pipe vent.

 

[EntropyUK]

It's a loft conversion in a semi detached with velux style windows front and back in the roof. The soil stack os a single stack and rises almost in the middle of the rear elevaltion between the two planned windows.

I love the idea of fitting an AAV. I just don't see how to relieve any potential back pressure when using the AAV.

 

[denso13]

I love the idea of fitting an AAV.

Go for it. Better to have an open vent, but if you can't, then AAV's are designed for this purpose.

 

[John D v2.0]

We have two stacks that join under the floor, one has an aav and the other an open vent. We always know when the drains are surcharged or blocked because we get bubbling air/gurgling in the downstairs toilet and the kitchen sink, which go into the aav stack. The trapped air has to get out somewhere. Other than that no issues.
If you have no open vent at all you rely on the neighbor's ones, which would block earlier, so you'd get more bubbling. And if the whole street switch to aavs then best of luck who gets it all coming through their shower tray (usually a shallow trap)
Total worst case, but it's useful to be aware.

 

[Entropy]

I really don't think BC would sign off an AAV unless I added a vent somewhere. The last 4 lines of the regs appear quite clear. I think I will have to have a chat with BC at project initiation to understand my options. Thanks all.

 

[denso13]

The last 4 lines of the regs appear quite clear

What "regs" are they? External AAV's are common, as are buildings with AAV's only.

https://www.floplast.co.uk/uploads/related-documents/BUsohExhe3Mqhq6jYrAqs9kLySHpgjrtGe5hGvjo.pdf

 

[Entropy]

That was lifted directly from Building regs part H. so now totally confused after reading that FloPlast document.

I will submit my plans using an AAV and go from there.

Thanks All for your advice.

 

[denso13]

Building regs part H

Approved doc H, which is guidance.