Replace soil stack/stench pipe with AAV

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).

Floplast seem OK generally.

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.

The rule is... Every 5th house needs a vent and every end of line. All the rest can have AAVs or HepVos.

erm..... thought you couldn't *legally* use AAVs outside ? something about freezing up? mines been fine for a decade however.....:>))

JimK

HepVO traps are not outside.

nor do they serve WCs

They do. They vent the whole stack. Now you know.

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?

do you know? :>)

JimK

Drivel doesn't know anything.

You must be new here.

Anyway the purpose of an AAV is quite different to a stack.

The stack is there to prevent positive pressure and (inflammable) gas build up in sewers.

The AAV is there to avoid vacuum when an adjacent device empties from sucking the traps dry.

Legally you need an open vent every few yards of sewer.

The general rule is one stack per house, and as many AAV's as you need.

You can get small or large ones . Or fit adaptors to them.

On Tue, 19 Jan 2010 01:44:17 -0800, JimK wibbled:

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

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.

In article , Tim Watts scribeth thus

So where would you buy cheaper?...

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.

In article , Tim Watts scribeth thus

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;))..

On Tue, 19 Jan 2010 12:04:01 +0000, tony sayer wibbled:

Err, Tony - both of those are online suppliers ;->

OK - Masterplastics, trading as

BES:

This is the AF32 Floplast (32/40/50mm AAV) I have:

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

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?

JimK

Drivel detected. You have only half a clue what you drivel about.

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.

oh quelle surprise....

Yes I know what HepVOs do I have some fitted here...

why don;t you read the rest of the thread FFS?

JimK