Height of Air Emittance Valve in stub stack

[Brooksie]

Am about to re-do a customers first floor bathroom where the stub stack has an air emittance valve roughly 1 meter above a swept T on the main discharge pipe.

If I could lower the valve to 'just' above the swept T the top of the valve would come below the top of the bath and would sit out of sight.

I've searched the web and can't find any minimum height regs.

Does any one know what the regs are for this?

Thanks
Brooksie

 

[sonray ltd]

are you talking about a 110mm valve ?

 

[Mike Jackson]

The valve should be above the spill over level of the highest appliance so it will need to be above the bath.

Mike

 

[Brooksie]

That would explain why it is currently around 30 cm above the lip of the bath. Yes it's 110 mm soil pipe and I think I shall leave as is, box the pipe in and tile around it with a detachable service lid.
Thanks for your help.

Brooksie

 

[TGor]

Hi Brooksie,
This is probably a bit late (I just got here)
You should make sure that the boxing is not air tight other wise it defeats the object .. Its an air admittance valve to admit air to compensate for reduced pressures in the system to avoid loss of trap seal.
best
TGor

PS whilst I know that AAV's ae a good product . my belief is its better to run a vent to the roof to avoid the possibility of failure & tampering leading to worse problems than aesthetics. .. call me old fashioned!!

 

[Mike Jackson]

Okay you're old fashioned. In my opinion you shouldn't even need an AAV on a modern system. If you fit at least one HepVo valve to the system this will work as a better AAV than the proper one and would completely do away with the need for one. Unfortunately the building regs haven't caught up with nodern technology yet.

Mike

 

[Bernie2]

Problem with Air Admittance valves, is that, that is all they do.
They don't help safe guard against back pressure like an open vent does. So depending on layout and main venting arrangments fitting an AAV can mean you get a lovely high speed coating of whatever is in the soil pipe come up at you from out of the wc basin trap if you get a blockage. Yes probably had a few near misses in my time and perhaps a couple of coatings. I can still smell it now!

As a reminder: make sure you don't rod backwards toward an AAV if your trying to clear a blocked drain. Its amazing how much mess a blown seal in a blocked wc can make. Oh! Dear all over my new carpet!

 

[stevetheplumber]

my gripe with aav systems is the lack of fresh air flowing through the drains old drains seldom actually smelt of what there designed to carry
the smell from some drains on relativly new housing estates is pretty ripe
when i first learned to lay drains all the inspectors carried a wooden ball about 3 inches in diameter which he inserted one end of the drain and it had to appear at the other end purely rolling with the fall of the drain

 

[feltham]

i dont know if you can reduce the the size of the aav but you can get them in 38mm and 42mm . this would look less sightly but not sure if your allowed to do this

 

[buffy27]

The valve should be above the spill over level of the highest appliance so it will need to be above the bath.

Mike

whats the craic,
in relation to the level of the aav ...why is this mike..

 

[Plouasne]

Okay you're old fashioned. In my opinion you shouldn't even need an AAV on a modern system. If you fit at least one HepVo valve to the system this will work as a better AAV than the proper one and would completely do away with the need for one. Unfortunately the building regs haven't caught up with nodern technology yet.

Mike

I beg to differ, if the system was correctly designed in the first place, there would be no need for these so called modern waterless traps

If the drain run was long, and unvented, no matter what type of waterless trap, AAAV, will be of any use

I agree with Bernie, and Steve, there should always be a vent to the drain for each property

Yet again poor theory/economics wins, over good practise

And if you want to "bugger up" a Hepsleeve no manhole drainage system, a dumpy milk bottle fits nicely down the roding access point

 

[John Flower]

Well the reasoning behind the fact that the valve has to be higher than the spillover level of the higest appliance is that these valves are not normally good at holding back a head of water if the stack became blocked. I agree that a properly designed soil stack Single or two pipe and a well designed drainage system with soil and vents terminating through the roof are a much better bet. Plenty of fresh air into the drain and no prooblems of drain smells entering the property or trap seals blowing ect. Modern technology is good but it is also very good at taking the art out of designing a system that works properly with quick fixes ect.

 

[RTPS]

The primary stack HAS to vent to atmosphere you cannot have a Dergo on the primary
only on the secondary, that is only if the drain system is connected together.
The AAV needs to be of the same size as the pipe it it connected to.

 

[WHPES]

PS re the title - Never fit an air Emittance valve to a stub stack. You do not want the drain gases in the room. These are only for on the top of septic tank systems.

What you should have is an Air Admittance Valve.

 

[RTPS]

PS re the title - Never fit an air Emittance valve to a stub stack. You do not want the drain gases in the room. These are only for on the top of septic tank systems.

What you should have is an Air Admittance Valve.

This was obviously a spelling mistake by the originator

 

[WHPES]

This was obviously a spelling mistake by the originator

First rule of engineering - Never assume ANYTHING!!

 

[darrenbea]

it needs to be 1000mm min above the bend

 

[Tony@ Studor]

Hi I know this is an old thread but reading it want to offer some proper advice rather than various people just having a stab at it, and saying things they think are correct.
If you want to know the answers read BS12056 and study EN12380. these are the standards for AAVs in the UK. they will show you that if the valve is A1 rated it can be fitted upto 1m below flood level, not all valves are rated as this.

 

[Guest123]

Hi I know this is an old thread but reading it want to offer some proper advice rather than various people just having a stab at it, and saying things they think are correct.
If you want to know the answers read BS12056 and study EN12380. these are the standards for AAVs in the UK. they will show you that if the valve is A1 rated it can be fitted upto 1m below flood level, not all valves are rated as this.

Thank you Tony for your useful advice. My most recent posts referring to AAV's do however point this out, especially the A1 rated ones by Floplast which I regularly use below the flood level of the highest appliance as it eliminates the need to box in a soil stack in a bathroom and thus creates more space.