air inlet valve on vent stack

[Lower]

we have a cast iron sewer vent stack that exits next to the bathroom window, approx 1m above. If we have gone away for a week or so and the weather has been hot, you can get smells from the vent in the bathroom. Can i fit an air inlet valve to the top of this stack or does the vent need to be able to expel fumes as well as suck air in?

 

[corgiman]

yes you can look up DURGO valve

 

[grrinc]

Air inlet valves let air in but stop whiffs coming out. A lot of them are for plastic pipes and are designed to fit them. Your cast iron pipe will be a different size and may need an adaptor. Also, I know of no AAV that can be used externally, they are not resistant to frost. If one does exist, I have never seen one and I have looked. Can anyone confirm this??

 

[Nige F]

Yes you can .............IN some circumstances .......look up online building regs . I think someone is "barking up the wrong tree" despite being a Royal Pet

 

[ChrisR]

Ang on, the venting property of the open end would be completely defeated by something like a Durgo. It may well NEED to let pressure escape from the system to stop traps passing bubbles. (depends on the proximity of the next vent - see Bldg Regs)

Surely the proper solution is to extend the stack up another metre or whatever?

 

[Lower]

that's pretty much the point of my question. does the vent stack just ingest air or does it vent too?

 

[doitall]

It vents the head of the drain (gas) to atmosphere.

Air admittance valves cannot be fitted externally.