Air admittance values

[Russell Truluck]

I have an air admittance value in the crawl space with the top of the value 2" from the bottom of the floor insulation. Does anyone see an issue with that?

Thanks,
Russell Truluck

[David P. Valley]

No. AAV's are OK in a crawlspace or even inside a sink cabinet.

If I see more than one AAV in a home, then there are issues.

[Jeffrey R. Jonas]

Originally Posted by dvalley

No. AAV's are OK in a crawlspace or even inside a sink cabinet.

If I see more than one AAV in a home, then there are issues.

Agreed.

[Jeffrey R. Pope]

I've never heard of AAV's being allowed in a crawl space. Admittedly, I don't see many AAV's in CA (because they're not allowed by State Standards) but from what I know they're required to be near or above the flood level of the fixture(s) they serve.

It seems to me that an AAV in a crawl space is just asking for trouble. . .

David - why would multiple AAV's be a problem?

[Jack L. Gilleland]

If you had an AAV below the level of the trap, what would be the point. Gases are supposed to rise through the system.

[Russel Ray]

Originally Posted by jpope

Admittedly, I don't see many AAV's in CA (because they're not allowed by State Standards) but from what I know they're required to be near or above the flood level of the fixture(s) they serve.

Once again we apparently do things differently down here in San Diego. I have whole subdivisions of expensive homes with multiple AAV's in the houses: Rancho Bernardo, Scripps Ranch, 4S Ranch, Del Mar Highlands, Del Mar Heights, Rancho Penasquitos, and probably a few others. The first time I ran into them back in 2001, I called my plumber and he didn't have a problem with them. Then I called two other plumbers and they didn't have a problem with them either. That gave me the concensus that I was looking for.

When I find one under the kitchen sink, I know they will be in the bathrooms and the laundry, and, indeed, they area.

[David P. Valley]

Originally Posted by jpope

David - why would multiple AAV's be a problem?

They make sewer stacks for that reason.

[Russel Ray]

But why would multiple AAV's be a problem?

[Michael Larson]

Originally Posted by rray

Bu why would multiple AAV's be a problem?

Probably not a problem unless there is no main vent stack for the stucture.
They are not a perfect devices or without problems in the long term.

Your AHJ and codes would determine what is allowed in your area.

[Russel Ray]

Originally Posted by mlarson

Probably not a problem unless there is no main vent stack for the stucture.

Exactly.

Originally Posted by mlarson

They are not a perfect devices or without problems in the long term.

As with anything, though, right?

Originally Posted by mlarson

Your AHJ and codes would determine what is allowed in your area.

As the AHJ's have already done here.

I find multiple AAV's in the rich areas with McMansions. The reason is because all those ugly vents sticking up through the roof make the roof ugly. So when one has 19 bathrooms and 37 sinks, one really doesn't want 37 doohickeys sticking up through the roof making the roof uglier than it already is.

Fewer doohickeys sticking up through the roof also make it easier for our South-of-the-Border roofing labor to install the roof. That flashing around 37 doohickeys can be soooooooo troublesome.

[Jeffrey R. Pope]

The CPC does not recognize AAV's. As always, local jurisdictions vary. I've seen them in subdivisions as well as in manufactured homes - it usually depends on whether the area is incorporated within the county, having their own building standards. Unincorporated areas will usually be following State Codes.

In most homes (where I've seen AAV's), they've been installed in the attic. Manufactured homes will generally have them at each fixture (that's why I asked), but I can't recall ever seeing one in a crawlspace. . .

[David P. Valley]

Originally Posted by rray

Bu why would multiple AAV's be a problem?

I never stated that they are a problem. I stated that there will be issues with multiple AAV's.

If construction is well planned ahead of time, and sewer stacks are considered into the plan, AAV's are not needed because multiple fixtures can be added into a single sewer stack.

Normally I see a single AAV's in manufactured homes (at the kitchen sink) due to the distance from the bathroom to the kitchen. I hardly ever see AAV's in SF homes.

[Russel Ray]

Originally Posted by dvalley

I stated that there will be issues with multiple AAV's.

So I'll repeat the question, which you quoted:

Originally Posted by rray

But why would multiple AAV's be a problem?

Or, in other words, what "issues" would there be with multiple AAV's.

I'm trying to learn something here. Thanks.

[David P. Valley]

Originally Posted by rray

So I'll repeat the question, which you quoted:


Or, in other words, what "issues" would there be with multiple AAV's.

I'm trying to learn something here. Thanks.

Russel,

Use your head for something other than a hat rack....

[Russel Ray]

Originally Posted by dvalley

Russel,

Use your head for something other than a hat rack....

That's what I thought. You can't come up with any "issues." That's okay. I did learn something.