Air Admittance Valves in the U.S.?

[John E.]

I know that AAV's (vent valves) are common in Europe, but are they in common use and accepted by inspectors in the U.S.?

Thanks,

[Joseph Meehan]

We call them vacuum breaker valves. I don't know all the rules and you may find that they may be different in one area from another. I believe that generally you will find that it is considered good practice to avoid them by using a vent stack.

[Plan Review Section]

They are approved for use by section P3114 in the IRC. Can be used for all venting except that a single vent stack or stack vent is required in the system to relieve positive pressures. That being said, there are several states where the plumbing unions is strong enough to have them banned (cuts into a plumbers profits don't ya know.) So it's really up to the locals as to whether that are permitted or not. (There's nothing wrong with the actual product, been used for many, many years here in the US without problems, just a profit issue with plumbers is all.)

[Ron]

Excuse me?

The unions have nothing to do with code restictions. They may limit the materials that they will allow their members to install (back in the 70's, even though NoHub cast iron was code approved, the local here would only allow the plumbers to install service weight), but, generally, they have no control over codes.

Also, your comments "cuts into a plumbers profits don't ya know" and "just a profit issue with plumbers is all', are rediculous statements. You're mixing up the union (employees) with the contractors (employers).

Contractors must use whatever code approved materials and methods are available to them in order to REDUCE the cost of jobs so that they will be competetive. Even with today's building boom, the profits are less than they were because the "burden" (insurance, overhead, gas prices, etc) are out of control and whatever "profit" is left over at the end of a job gets eaten up by the overhead.

[Joseph Meehan]

I have seen them fail. I am sure that their failure rate is higher than conventional stack venting. As someone suggested the mineral content of the water supply in some areas could cause a higher failure rate and those are the areas more likely to have banned them. Like most regulations, the reason for the regulation may not be obvious and people tend to ignore them when they don't see the reason. That is really dumb thing to do and to assume that there is not a good reason for a regulation.

[yourname]

well, I wouldn't go so far as to say they have no say. Copper drains in commercial buildings in mass makes zero sense, but there they are, ton o cash for the plumbers. PVC is just as chemical proof[depending on chemicals] as copper

[Joshua Putnam]

AAVs are specifically allowed by IRC. They must be accessible, located

4" above fixture drain when used for individual fixtures, 6" above flood level of highest fixture if used for a stack vent. If located in the attic, must be at least 6" above insulation.

UPC leaves it up to the local jurisdiction.

[Rudy]

.. accepted by inspectors in the U.S.?

Yes

Studor Mini vent

[Ron]

What does the mineral content of the water have to do with a AAV? It's sewage/venting we're talking about here.

[Joseph Meehan]

Likely not much most of the time.

[Larry Bud]

An even dumber thing to do is to assume that every regulation has good intentions behind it.

[Robert Gammon]

All depends on how far above the trap the AAV is installed.

In some locations, the installer may have gotten lazy and put it too close(ie 4 inches or less). Repeated splashing of water against the valve leaves mineral deposits which then cause the valve to stop operating.

In new construction, take the valve up to the next floor before installing the AAV, and we avoid the problem. 4-6 feet of air column under the AAV and there will be NO moisture driven up to it.

R> What does the mineral content of the water have to do with a AAV? It's

[PPS]

It was the Minnesota Pipe Trades Association who just got in banned in Minnesota. Their argument (Minnesota Plumbing, Heating and Cooling Contractors and the Minnesota Mechanical Contractors Association) was based on the controversy that the use of air admittance valves to will provide a vent terminal inside a building, which is prohibited by the Minnesota Plumbing Code.

On the other side of the argument was the Minnesota Department of Labor and Industry Plumbing and Engineering Unit (who had been accepting the method of venting) and Studor, Incorporated.

Of course they can fail, even vents terminating outside can fail (freeze over, sealed by snow or birds nest, etc.) But the truth is, they have a proven track record of not failing, and it's for this reason that they made it into the new International Codes.