Currently we have sodding godawful stench pipe which runs in the corner of the house (it's an "L" shaped bungalow). Next door (2 storey house) has a stench pipe running to above their eaves.
Is is possible to replace our pipe with a 120cm pipe capped with an air admittance valve ? 120 cm will put it above the overflow of all sinks in the house.
Is it as simple as remove old cast iron pipe, fix a slightly smaller pipe into exposed pipe with sealant ?
On Mon, 18 Jan 2010 04:46:09 -0800, Jethro wibbled:
Well, there is one problem - and I would advise a quick shufty at the appropriate Building Regs document (Google for "Approved Document H"):
An AAV does not deal with positive air pressure (ie venting the sewer to the atmosphere. AAVs are used where local suction effects (due to flushing the bog for instance) are liable to suck u-traps dry.
I think you will need at least one vent to atmosphere, but it *may* be possible to provide one dry vent in 32mm.
Suggest looking at the document I mentioned, pages 10-14 and 23 (actual page numbers as printed, not PDF numbers).
You cannot do it if you are the end of sewer line. Yes it is OK to do. Look at HepVO traps on all sanitary appliances,and do away with the whole stack.
sigh.... i was clarifying that there isn't a hepvo for a bog...for sinks, baths yes but not for a 110mm bog connection...
how can the op "do away with whole stack" as you advocate - what about the bog connection? it will still need some stack to that and above for flood regs? if topped with an AAV - technically illegal outside I believe?
I came across an AAV that claimed to be rated for outside use - can't now remember who made it.
That doesn't solve +ve pressure concerns though. However, if my initial scan of Part H was right, it may be possible to vent somewhere more convenient in 32mm and use AAVs on each branch to deal with -ve pressures. OP will have to satisfy himself on those points though, but Part H has lots of helpful diagrams.
I concluded I needed a >75mm vent pipe (used the standard 82mm pipe) but that was the main vent (+ve and suction) to an entire branch of underground drains with various tees - though the BCO said it would clearly be fine with something smaller, it wasn't really a problem and like 110, 82 is tough old stuff suited to underground and rooftop deployment.
I'm not a fan of unnecessary AAVs, so I'm deploying them only as and where provably needed. eg, I will have one on the bathroom bog stack as that is it's own branch with the basin attached and bogs create large amounts of suction. As others have said, a HepVO on the basin would also work.
I didn't bother with AAVs on the 5m 50mm branches to the kitchen and bath which feed into a separate 110 branch (no bog on this section) and everything works fine, unsurprisingly, as the water only fills half the
50mm pipe in the worst case use, leaving a continuous air gap above it - no way for suction to form.
On Tue, 19 Jan 2010 10:25:08 +0000, The Natural Philosopher wibbled:
And don't buy them at the builder's merchants - notorious for overpricing.
I'm trying my luck with a Floplast 50mm AAV and 110-50mm adaptor for my bog. Initial mouth tests indicate the Floplast is silent (some AAVs can be quite "farty") and a good free flow in one direction. If it causes problems, I'll upgrade to a 110 AAV, but those are quite bulky, especially as I need to put in a stub pipe vertically to get it above the flood line.
On Tue, 19 Jan 2010 11:06:23 +0000, tony sayer wibbled:
BES, MasterPlastics to name two, depending on the part.
First, I'd decide on the part (110 or 50mm), then either search by 110 AAV or narrow it down to a specific part number, say FloPlast and search for that.
None of them appear to have branches around here (Cambridge) still it seems if you haggle a bit they'll drop the price a bit .. sometimes like some heating bits less than what you can buy online;))..
which as Drivel says could technically be achieved by HepVOs on say the sink/bath without the need for an AAV - *unless* the BCO insists on some other arrangement. If BCO's being picky (and AIUI) you can't
*officially* use an AAV outside so what other arragement could the OP do - Tim's 32/80mm vent pipe seems the only one?
Spose *officially* BCO would have to decide whether OP's house can have stack pipe altered given that it sounds like it's the OP's houses' only stack?
Not another one. Another know-it-all. The basin, shower and bath are connected to the same stack the toilet is on, air ingress is via the HepVos. Look at Hepworths info. On the web. Do a Goodle on HepVo on this forum.
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