The new International Plumbing code allows the use of “air admittance valves” which can be used in place of a vent, especially at the kitchen sink where drilling through 3 or 4 studs for a vent pipe would be necessary.
Are there any plumbers or others who have had experience with these valves, and are confident with their use, or otherwise. My local plumbing inspector is not happy with them.
Bob
Replies
Cheater vents -- I think the real name is Stutor vents -- are devices which are installed under the sink. They allow room air to get into the drain lines. But they do not allow sewer gas to get into the room air.
Some local inspectors and codes have allowed these for quite a while. Other areas have been more reluctant. It is important to note that these can not be used to vent entire systems. They are single-device vents, and can only be used as you saw in the code.
Unless you're the lead dog, the view just never changes.
A Stutor vent, or air addmittance valve, should never let sewer gases into the house. The diaphram is only pulled open when water is flowing in the drain pipe, i.e. it admitts air, so the drain line does not air lock, and gulp air through the drain. If you smell sewer gas when a AAV is used, it is most likely a defective valve. Ideally they should be set at or above the flood plain of the sink if it is an island install. They may also be installed in the attic, above the level of the insulation.
Dave
But one would suspect that most inspectors would object to installing these in an attic, given that they should only be used when conventional venting is "impractical", and it's hard to argue that in an attic.
They are allowed in the IRC.
I asked my inspector about them, he said "Well, that's what it sez"
Asked about the toilet, don't remember what he said to that one. I think the code is/was unclear is why I asked.
Sure better than holes in the roof........
Joe H
As a maintenance man, I'm definitely not a plumber, I had to read up on these vents before deciding that one of these units was the only reasonable solution. The place I used one was where a bar had a sink in an island. As first put in there was no way for air to get into the pipe before the 'P' trap.
When water was dumped down the drain in any significant quantities the plug of water would create a vacuum that would such out the water sealing the 'P'trap. This allowed sewer gas to travel up through the unsealed trap and escape into the environment.
The people sitting at the bar around the island all start looking funny at each other before walking off. At least one customer advised the bartender, a cute blond lady, to see a gastroenterologist.
As I remember it there were tight requirements about how close to the trap it had to be, as I understand this is to make sure it is a location where vacuum relief is needed as opposed to an outlet for air, and also that the unit had to be something like 6" above the top or overflow of the sink.
It worked well. No more fart alarms. From this limited experience I would say these units are fine where appropriate and installed strictly according to code. They are not a substitute for a vent pipe that can exhaust air in addition to taking it in.