Good article on Air-Admittance valves

The air-admittance valve debate heats up.

As the three remaining model plumbing codes are finalized for the 2012 editions, the one difference that really sticks out is each code’s approach to air-admittance valves. Two codes are definitely struggling with the concept of AAVs, while the other is doing just fine.

The code doing just fine is the ICC International Plumbing Code. In the 2012 edition, it expanded the use of AAVs with the addition of the newer standard ASSE 1049. This standard is applicable to AAVs for chemical waste applications. Chemical and special waste systems can now be vented with an AAV provided it is certified for resistance to the chemicals involved. One manufacturer (Studor) has developed a polypropylene AAV that conforms to ASSE 1049.

IAPMO’s Uniform Plumbing Code and the PHCC National Standard Plumbing Code are struggling with their references to AAVs. Both codes want their identity to include that they do not allow AAVs. That isn’t really accurate, but it is what they would like you to believe.

At the recent meeting of the IAPMO Standards Council, an appeal to add AAVs to the 2012 Uniform Plumbing Code was denied. Basically, the reason for denial was that the will of the membership was opposed to AAVs. That’s not much of a reason when a code is a consensus document. Shouldn’t there be a proper technical justification?

**Previous IAPMO Standards Councils used to require the Plumbing Technical Committee to come up with proper justification for not accepting AAVs other than, “We just don’t like them.” That has never really happened, but words are thrown together that still boil down to, “We just don’t like them.”

**On many occasions, the Plumbing Technical Committee has approved the recognition of AAVs only to have the letter ballot fail to obtain a two-thirds majority. Hence, it is not the will of the IAPMO membership. It is the will of the “1/3 plus 1” minority.

In some people’s minds, 25 years of use in the United States and the installation of more than 20 million valves is not justification for accepting a product. Forget all the laboratory tests that prove AAVs are equivalent. Some people want field testing. I’m not sure if it will take 50 years of use and 100 million valves installed before the field testing is proven. If you think about it, it wasn’t that long ago we brought plumbing indoors in this country.

Aren’t They Already There?

What the Standards Council and the membership seem to ignore is the fact that AAVs already are permitted by the Uniform Plumbing Code. Section 911.0 allows the engineering of a vent system. Any engineered design can incorporate an AAV. Engineers would be smart to use the requirements in the International Plumbing Code to validate the engineered vent design.

The National Standard Plumbing Code is somewhat different in its approach to AAVs. It has included AAVs as an engineered design in its appendix for quite some time. The problem is it requires every use of an AAV to be on a drawing sealed by a P.E. That is not a problem in a commercial building, where P.E.s already are required to sign and seal every plumbing engineering drawing. The problem occurs in residential or minor repairs where plans are not required.

A proposed change would have added AAVs to the venting section without the need for an engineered design. After all, the code already allows AAVs. The Code Committee turned down the change with the reason reduced to, “We just don’t like them.” Of course, this is rather strange since AAVs are allowed in an engineered design.

The problem with the National Standard Plumbing Code is there is no membership vote or oversight of the Code Committee. What the committee says, goes. That’s not the best system in the country for developing a plumbing code. It also may be the reason it is used by only one state (New Jersey) and parts of other states, including Maryland.

Costly Appeal

The proponent of the code change attempted to appeal the decision of the Code Committee. That is, until he was informed such an appeal would cost more than $20,000. That’s right, PHCC charges more than $20,000 to appeal a decision of its Code Committee.

There is absolutely no way to justify charging someone this amount of money to appeal a questionable decision by a code committee. But PHCC is of the opinion that an appellant should pay all the costs associated with an appeal, including the staff time. I find that outrageous.

As a result of this high cost, the code-change proponent did not appeal the Code Committee’s decision to not accept AAVs in the venting chapter.

The result is that two codes will again avoid identifying AAVs in the venting section of their respective codes while the International Plumbing Code embraces the acceptance of AAVs.

When looking at the map of code acceptance, the International Plumbing Code dominates with statewide adoptions. The Uniform Plumbing Code has many states, but not nearly the number ICC has. Interestingly, many states that have adopted the Uniform Plumbing Code also have amended the adoption to accept AAVs.

As for the National Standard Plumbing Code, it is almost a nonentity. With only one statewide adoption, there isn’t any major push to use the code in other states or jurisdictions.

Perhaps IAPMO and PHCC will realize that the lack of recognition of AAVs has hurt their stature, not helped it when dealing with acceptance of the code. I believe we have reached the point where those who “just don’t like AAVs” should admit that they are wrong. It is time to move on.

I wish all of you a Merry Christmas, Happy Hanukkah and a wonderful New Year.

Julius Ballanco, P.E., CPD
Julius Ballanco, P.E., is Editorial Director of PM Engineer and president of J.B. Engineering and Code Consulting, P.C. in Munster, IN. Prior to starting J.B. Engineering, he served as head of plumbing and mechanical engineering for Building Officials and Code Administrators International, one of the organizations that formed the International Code Council (ICC). His engineering consulting work includes the design of plumbing, mechanical and fire-protection systems; forensic engineering; training; and serving numerous manufacturers in different capacities. In addition, Ballanco is the current president of ASPE and a member of both ICC and IAPMO. He can be reached by e-mail at

Thanks for info… Roy

So building codes aside, if you find an AAV with functional drainage and no smell, you do not call it out?

Yes I call attention to where it is located. If it cannot be located easily and viewed for operation I will inform the client of a correction needed.
I also point out that since it is a mechanical part it can fail so a good CSA unit should be considered not a cheap one you find in lower plumbing supply places.

If AAV’s are the excepted norm than why the disparaging consensus and comments.

Accepted by who?

They are permitted in some situations.

They remain a mechanical device subject to failure.

This is an older public posting on AAVs, giving a well spoken position from Studor, makers of a quality AAV:

Thank you for the Information on AVV. I truly appreciate your effort.

My experience with AAVs (sometimes called cheater vents) is mostly in how they are installed incorrectly. In Ontario, they need to be installed above the Flood Level Rim of the fixture they serve (or as high as possible), and they need to be accessible for service. Most are not.
When you see them, it was more than likely a DIYer who was taking shortcuts. It should signal the need to take a much closer look at the plumbing. Certainly worth mentioning to your client.


Thanks Dan I recommend you go to the top
(Control PanelFAQ[Community]( )

Click on Control and put in your info Thanks … Roy