Ventilation of WC Stack Pipe

P

picorette

Registered User
Messages
126
We have had some alterations made to our house.
There are now three toilets, one above each other, and each connected to the same stack pipe.
This stack pipe finishes in the top bathroom.The builder has put something called a dorco / durgo(?) valve on the top of this. It does not protrude through the roof to the outside as I thought it would have to, and there is no other stack pipe in our house.

Does anybody know if this is correct?
Does it comply with Building Regulations?
Are there likely to be future problems?

Thanks
 
Pico

I don't know what a dorco / durgo is but if this stack is not vented to outside you have problems and it does not comply with building regs
 
glenamaddy said:
no
Click to expand...

No to what?

Air admittance valves (AAVs) are pressure-activated, one-way mechanical vents, used in a plumbing system to eliminate the need for conventional pipe venting and roof penetrations. A discharge of wastewater causes the AAV to open, releasing the vacuum and allowing air to enter plumbing vent pipe for proper drainage. Otherwise, the valve remains closed, preventing the escape of sewer gas and maintaining the trap seal. Using AAVs can significantly reduce the amount of venting materials needed in a plumbing system, increase plumbing labor efficiency, allow greater flexibility in the layout of plumbing fixtures, and reduce long-term maintenance problems associated with conventional vent stack roofing penetrations.
 
Davy Jones, does that mean that you think that a Durgo valve can be used in this situation?

The Building Regulations only state that a drainage system as may be necessary for the hygenic and adequate disposal of foul water from the building.

In the guidance notes under ventilation of disccharge stacks, it says:
' To prevent water seals in the traps from being lost by pressures which can develop in the system, stacks should be ventilated.'

No mention of air admittance valves.

However, the UK Building Regulations say:
'Ventilated discharge stacks may be terminated inside a building when fitted with air admittance valves complying with BS EN 12380:2002'.

Is there anyway of getting a definitive answer?
 
had a quick look over document H there is no mention of durgo valve (AAV). However the durgo valve serves the purpose of the stack, as in, it equalises pressure within the system. Personally I would be confident that it would work 100%.
Our regulations haven't been updated in a while and when they are, I would expect them to include AAV like the UK.
If you really aren't happy then you could always reduce the 4" pipe(only in the dry part of stack) down to 1 1/4" and then run it outside. Much easier to route and terminate when the pipe is 65% smaller. This is laid out in Document H sub section 1.4 paragraph 6.

Finally, in my own experiance I have used them when I have had too and they work 100%.
 
After a search through other Discussion Boards (where most posters say you cannot do it, often vehemently), I found this British Board of Agrement Certificate for the Durgo valve which confirms that it is permissable in my case.

[broken link removed]

Thanks for your help, Davy Jones. Most people seem wary of a new invention that goes against established thinking.
 
I seem to remember that AAVs are only recommended to serve a single bathroom and a maximum number of fittings (as opposed to a series of bathrooms). You could give Wavin a call, they're usually helpful with free advice (Tel 01 802 0200).
 
Mr Sparkle said:
I seem to remember that AAVs are only recommended to serve a single bathroom and a maximum number of fittings (as opposed to a series of bathrooms). You could give Wavin a call, they're usually helpful with free advice (Tel 01 802 0200).
Click to expand...

I can't see how that would be the case. the volume of potential water in the system is irrelevant, the aav should operate regardless of amount of useage. I might give them a call to find out for sure.
 
pico said:
....Thanks for your help, Davy Jones. Most people seem wary of a new invention that goes against established thinking.
Click to expand...

While in general I might agree, when dealing in a situation where the downside includes the risk of death I tend to err on the side of caution.
 
Risk of death is a bit extreme don't you think? I assume you are referring to meth gas. septic tanks are vented at source and main sewer lines are vented throughout there runs. There is nil chance of meth gas poisioning, in that case people would drop dead everyday from leaks within their own home e.g bad seals at back of toilets etc. The only places it can be a problem is on ships etc where sewage is in tightly sealed containers and pipework.
And if there was any risk do you really think they (AAV) would be included in the UK building regs?
 
You must log in or register to reply here.
Back
Top