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  1. #1
    Jerome W. Young's Avatar
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    Default Is this an AAV or Mechanical vent

    this was installed at a bar sink. It reads liquid vent across the top. The springs indicate a mechanical vent if i am correct. The black color isnt a sure bet it is the wrong type for residential use? Is this allowed in residential homes or just mobile homes? Is this the manufacturers recommendation or code? I am dealing with a plumber here localy who thinks this application is fine and that i do not know what i am talking about.
    Thanks for the help!
    Jerome

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  2. #2
    Jerome W. Young's Avatar
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    Default Re: Is this an AAV or Mechanical vent

    sorry it says auto vent across the top


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    Default Re: Is this an AAV or Mechanical vent

    An AAV is a mechanical vent as well. They all should be baned.... sorry I just had to rant a little.

    Last edited by Ron Hasil; 05-21-2011 at 03:30 PM.

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    Default Re: Is this an AAV or Mechanical vent

    Jerome,

    Those are not allowed to be used in homes, those are only allowed in mobile homes.

    Jerry Peck
    Construction/Litigation/Code Consultant - Retired
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  5. #5
    Jerome W. Young's Avatar
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    Default Re: Is this an AAV or Mechanical vent

    Ok, thanks again. I just wanted to confirm that. I know we discussed this before.


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    Default Re: Is this an AAV or Mechanical vent

    Where do I locate the code that states that air admittance vents are not allowed in non manufactured homes? I see them on rare occasions in homes and it appears that the 2009 IRC Section P3114 allows them to be installed in homes.


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    Default Re: Is this an AAV or Mechanical vent

    Quote Originally Posted by Gary Mohel View Post
    Where do I locate the code that states that air admittance vents are not allowed in non manufactured homes?
    That is not an AAV, that is a mechanical vent. Mechanical vents are not allowed regular built housing.

    I see them on rare occasions in homes and it appears that the 2009 IRC Section P3114 allows them to be installed in homes.
    There is a difference between AAVs and those mechanical vents: Those operate via a spring and AAVs operate by gravity and air pressure differences.

    Chicago, and Illinois, does not allow AAVs either as they consider them "mechanical" vents. That is the same place (Chicago) which does not allow NM cable and other more modern construction products - possibly because it is highly union controlled and new construction products save installation time, which is a loss for the union and its members.

    Jerry Peck
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    Default Re: Is this an AAV or Mechanical vent

    Quote Originally Posted by Jerry Peck View Post
    That is not an AAV, that is a mechanical vent. Mechanical vents are not allowed regular built housing.



    There is a difference between AAVs and those mechanical vents: Those operate via a spring and AAVs operate by gravity and air pressure differences.

    Chicago, and Illinois, does not allow AAVs either as they consider them "mechanical" vents. That is the same place (Chicago) which does not allow NM cable and other more modern construction products - possibly because it is highly union controlled and new construction products save installation time, which is a loss for the union and its members.
    Jerry, it is also not allowed since it does not allow for air to be expelled from the system, also it is something that fails and needs replacing. I know I had this argument before but AAV's are mechanical, they have a moving part inside to operate. In the past though people argued with me that they never fail since the only part that moves is a ball, there is no spring to get rusted. Well I see many DIY threads where people are complaining about a stink in their home coming from the AAV, or their drains are not draining but when the remove the AAV the water goes down. I would call these failures.

    Also Illinois is not the only state that does not allow AAV's, last time I checked there where 13 states that did not allow them and a hand full that would allow them only if you submit plans and get a pre-approval to use them on your job.


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    Default Re: Is this an AAV or Mechanical vent

    According to the plumber helping me with my project, they (either AAV or MAV) are not allowed in NM unless you can justify it to the plumbing inspector that running a vent would be too difficult.

    Jim Robinson
    New Mexico, USA

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    Default Re: Is this an AAV or Mechanical vent

    Quote Originally Posted by Ron Hasil View Post
    Jerry, it is also not allowed since it does not allow for air to be expelled from the system, also it is something that fails and needs replacing. I know I had this argument before but AAV's are mechanical, they have a moving part inside to operate. In the past though people argued with me that they never fail since the only part that moves is a ball, there is no spring to get rusted. Well I see many DIY threads where people are complaining about a stink in their home coming from the AAV, or their drains are not draining but when the remove the AAV the water goes down. I would call these failures.
    Ron,

    If you want to use the argument that they should not be allowed "because they fail", then NOTHING should be allowed "because EVERYTHING fails".

    That argument does not hold up - EVERYTHING FAILS at some point in time, which is why the AAV are required to be accessible, which is also why DWV systems are required to have clean outs, which is also why ... the list is endless.

    Jerry Peck
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    Default Re: Is this an AAV or Mechanical vent

    Quote Originally Posted by Jerry Peck View Post
    Ron,

    If you want to use the argument that they should not be allowed "because they fail", then NOTHING should be allowed "because EVERYTHING fails".

    That argument does not hold up - EVERYTHING FAILS at some point in time, which is why the AAV are required to be accessible, which is also why DWV systems are required to have clean outs, which is also why ... the list is endless.
    I agree with Jerry. Everything will fail at sometime in its life.

    When a home has AAV's it must also have a DWV that goes to the atmosphere (outside the envelope of the home). One main reason is to allow for air to be expelled in the plumbing system.

    I like AAV's for kitchen islands and situations that would make it difficult or impossible for a DWV to be installed. I see nothing wrong with them. The naysayers for the most part are plumbers or folks who rely on the plumbing trade. The same group dislike PEX and for the same reasons. It cost less to install.

    Scott Patterson, ACI
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    Default Re: Is this an AAV or Mechanical vent

    Then explain to me why codes do not allow mechanical traps? They can be easily replaced when they fail.

    As for having a single vent to the roof, it is not enough. I have seen where AAV's where installed on a 3 story building. Each kitchen sink had their own AAV and drained into a common sink stack. When the guy on the third floor filled both sides of his sink you can hear the AAV draw in air (working fine in this case) but the guy on the first floor started to get gurgling out of his sink. The reason why is as the slug of water is coming down the stack it is building up positive pressure in the drainage system which the AAV can not deal with so the trap seal on the sink is compromised.

    Studer does make a mechanical device you can install to help buffer the lines from this positive pressure, which is another component that can fail. Does vent piping fail, yes but not very often and mostly due to improper designed systems. I have been doing plumbing for over 20 years and only seen 3 clogged vent lines and 5 vent lines that rusted out and needed replacing. In each case it was poor design.

    Now for Pex, guess what, Illinois allows pex. heck they even allow PVC for water distribution,( cold only) CPVC is needed for hot. I do not like pex or CPVC, I do prefer copper and galvanized systems, not because they require more work to install but I know 30 years down the road my installs still will be working where as PVC and Pex piping only comes with a 10 year guarantee, and has been proven to fail more often than not.


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    Default Re: Is this an AAV or Mechanical vent

    Quote Originally Posted by Ron Hasil View Post
    Then explain to me why codes do not allow mechanical traps? They can be easily replaced when they fail.
    For the same reason they do not allow 'S' straps, which have no moving parts of any type.

    Jerry Peck
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    Default Re: Is this an AAV or Mechanical vent

    Quote Originally Posted by Jerry Peck View Post
    For the same reason they do not allow 'S' straps, which have no moving parts of any type.

    No. They do not allow S-traps becasue they are self siphoning. Well they do allow them in urinals and water closets.


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    Default Re: Is this an AAV or Mechanical vent

    Quote Originally Posted by Ron Hasil View Post
    No. They do not allow S-traps becasue they are self siphoning.
    Yes, for the same reason - they do not work without problems. You stated the problem with 'S' straps.

    Well they do allow them in urinals and water closets.
    Which are fixtures which automatically refill after self-siphoning, so they work there.

    Sinks, lavs, other fixtures do not automatically refill the 'S' strap after self-siphoning, so they ('S' traps) do not work without problems at those other fixtures.

    In one case you WANT self-siphoning, it is in the design of the fixtures, in the other case you DO NOT WANT self-siphoning as it is not in the design of the fixtures.

    Jerry Peck
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    Default Re: Is this an AAV or Mechanical vent

    Quote Originally Posted by Ron Hasil View Post
    Now for Pex, guess what, Illinois allows pex. heck they even allow PVC for water distribution,( cold only) CPVC is needed for hot. I do not like pex or CPVC, I do prefer copper and galvanized systems, not because they require more work to install but I know 30 years down the road my installs still will be working where as PVC and Pex piping only comes with a 10 year guarantee, and has been proven to fail more often than not.
    Does Chicago or Cook County allow PEX?

    Scott Patterson, ACI
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    Default Re: Is this an AAV or Mechanical vent

    Quote Originally Posted by Scott Patterson View Post
    Does Chicago or Cook County allow PEX?
    There is some cities in Cook County that allows Pex. I am not 100% sure on Chicago itself.


  18. #18
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    Default Re: Is this an AAV or Mechanical vent

    Picture is not as good, but is this the same type of vent?

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    Default Re: Is this an AAV or Mechanical vent

    Air Admittance Valve. They are listed and recommended for island sinks, and are not restricted to mobile homes. IPC Sections 903.3, 905.1, 917. When used with an island sink, they are to be located above the flood plane. There is an exception which allows them to be located at or slightly below the flood plane, if the counter top does not extend above the top of the sink. They can be used anywhere in the waste pipe system, and must be accessible.


  20. #20
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    Default Re: Is this an AAV or Mechanical vent

    Either type of vent, if it goes bad, will either keep the water from draining properly or you may get an odor in the home if it sticks open ..................... change them if they go bad. One of those symptoms will be noticed. If no one does anything about it it is no different than an open vent to a home or poor draining pipes. The same results will happen. The concern needs repairing just as the vent going bad. Spring loaded may keep it from opening. Same thing. A concern will be noticed and if it is not .. well, I already mentioned that.

    Needing to be banned? Well then they should ban anything that is toxic to eat or drink. Kids die in the multitudes due to those products ... and AAVs


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    Default Re: Is this an AAV or Mechanical vent

    Quote Originally Posted by Jimmy Roberts View Post
    Air Admittance Valve. They are listed and recommended for island sinks, and are not restricted to mobile homes. IPC Sections 903.3, 905.1, 917. When used with an island sink, they are to be located above the flood plane. There is an exception which allows them to be located at or slightly below the flood plane, if the counter top does not extend above the top of the sink. They can be used anywhere in the waste pipe system, and must be accessible.
    An AAV and a Mechanical Vent are not the same critter. Yes, they perform the same function but their construction is different. Mechanical vents will have a spring that over time will become weak and fail.

    I do not think that any code allows for a mechanical vent inside a residental home. However, they do allow for an AAV.....

    I do not know of any exception (in print) that allows for an AAV or mechanical vent to be installed outside of their installation requirements by their manufacturers. They all require the AAV to be a min of 4" above the sanitary tee(above the drain line) and not the flood rim of the sink....

    This is a good paper on AAV's by Rex Cauldwell

    Attached Files Attached Files
    Scott Patterson, ACI
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    Default Re: Is this an AAV or Mechanical vent

    Quote Originally Posted by Jimmy Roberts View Post
    Air Admittance Valve. They are listed and recommended for island sinks, and are not restricted to mobile homes. IPC Sections 903.3, 905.1, 917. When used with an island sink, they are to be located above the flood plane. There is an exception which allows them to be located at or slightly below the flood plane, if the counter top does not extend above the top of the sink. They can be used anywhere in the waste pipe system, and must be accessible.
    As Scott said, that is a mechanical vent and is not allowed a site-built or modular home, those are only allowed in manufactured (think 'mobile' homes).

    AAVs, on the other hand, are allowed in site-built homes and modular homes ... except for in Chicago, maybe even in all of IL?? But then, Chicago does not allow NM cable either, and I am not sure they allow PVC for DWV piping either - VERY strong unions there and they work to keep the old labor intensive methods going, and going, and going ...

    Jerry Peck
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  23. #23
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    Default Re: Is this an AAV or Mechanical vent

    To All Posts,
    AAV's are problematic despite their successful infiltration into the plumbing industry. I agree with those who say "if it is mechanical..it will fail" and that includes any moving part.

    As an FYI, I was on the Studor website last month trying to familiarize myself with the product(s) since NY has just allowed stack aav"s and has removed all the requirements for relief vents on the horizontal drain within 4 branch intervals!!! It is interesting to note that Studor makes a Maxi-Filtra with a carbon filter to eliminate bad odors and keep those bad odors from coming into the building and is a 2-way valve for outdoor use only. Why?

    For individual fixture applications, there will always be a potential odor problem with the use of aav's in that, within the moment of usage (when the valve is open) the sewer gases living in the pipes have to go somewhere. These gases: methane (flammable), hydrogen sulfide (toxin), and a variety of mercaptans that smell really bad, congregate and can reach high levels of concentrations because there is no ventilation in that portion of the drainage system. Ergo, the word and action of "to vent" (to escape or allow passage) will occur as the law of physics apply. This may happen in a nanosecond but it usually happens several times during the usage of the fixture.

    So regardless of mechanical, ball or bladder it has to open sooner or latter and when it does the nasty little molecules can escape.


  24. #24
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    Default Re: Is this an AAV or Mechanical vent

    Tell your local plumber that he doesn't not want he's talking about. He might live in a mobile home and uses mechanical vents

    Good luck,
    Scott


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    Default Re: Is this an AAV or Mechanical vent

    A lot of people are suggesting that gas can escape from the sewer while the AAV is open. Keep in mind that NEGATIVE pressure is required to open the AAV. The AAV contains a spring, which assists atmospheric pressure, to close the AAV. To suggest that gas contained within the pipe, will somehow escape during a period of NEGATIVE pressure, lends a need for those persons to revisit the laws of physics. Also keep in mind that, the spring pressure and atmospheric pressure, do not cease to exist while the valve is open. As the NEGATIVE pressure in the pipe decreases, the valve is moving to the closed position. These AAVs were not an overnight invention, that slipped into the plumbing industry. Engineers with real degrees are behind this invention, and as in all other plumbing devices, UL and other testing agencies do not list these AAVs until they are proven effective. Also while bad mouthing AAVs, keep in mind that at least one atmospheric vent is required in all waste plumbing systems. Therefore, while the main stack is already vented to the sky, the AAV is there to relieve local (fixture) NEGATIVE pressure. On the extremely rare occasion when an AAV may fail, it is likely to be in the closed position. As you are aware, there has NEVER been a problem with a clogged atmospheric vent at a fixture (sarcasm). On the [more] extremely rare occasion when an AAV may fail in the open position, it will let you know. Of course, a rotten or cracked pipe will let you know the same way. Does this mean we should stop using joint gaskets in waste pipes, due to their possibility of failure? After all, these gaskets have been known to crack with age.


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    Default Re: Is this an AAV or Mechanical vent

    Quote Originally Posted by Jimmy Roberts View Post
    A lot of people are suggesting that gas can escape from the sewer while the AAV is open. Keep in mind that NEGATIVE pressure is required to open the AAV. The AAV contains a spring, which assists atmospheric pressure, to close the AAV.
    The AAV does *not* contain a spring. A mechanical vent *does* contain a spring.

    The AAV works on differential pressure and gravity - negative pressure opens the AAV, gravity closes the AAV.

    Jerry Peck
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  27. #27
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    Default Re: Is this an AAV or Mechanical vent

    Quote Originally Posted by Jimmy Roberts View Post
    A lot of people are suggesting that gas can escape from the sewer while the AAV is open. Keep in mind that NEGATIVE pressure is required to open the AAV. The AAV contains a spring, which assists atmospheric pressure, to close the AAV. To suggest that gas contained within the pipe, will somehow escape during a period of NEGATIVE pressure, lends a need for those persons to revisit the laws of physics. Also keep in mind that, the spring pressure and atmospheric pressure, do not cease to exist while the valve is open. As the NEGATIVE pressure in the pipe decreases, the valve is moving to the closed position. These AAVs were not an overnight invention, that slipped into the plumbing industry. Engineers with real degrees are behind this invention, and as in all other plumbing devices, UL and other testing agencies do not list these AAVs until they are proven effective. Also while bad mouthing AAVs, keep in mind that at least one atmospheric vent is required in all waste plumbing systems. Therefore, while the main stack is already vented to the sky, the AAV is there to relieve local (fixture) NEGATIVE pressure. On the extremely rare occasion when an AAV may fail, it is likely to be in the closed position. As you are aware, there has NEVER been a problem with a clogged atmospheric vent at a fixture (sarcasm). On the [more] extremely rare occasion when an AAV may fail in the open position, it will let you know. Of course, a rotten or cracked pipe will let you know the same way. Does this mean we should stop using joint gaskets in waste pipes, due to their possibility of failure? After all, these gaskets have been known to crack with age.
    Well...where to begin? I think the main point we can all agree to is that mechanical or moving parts can and will fail and some people can smell sewer gas better than others. Beyond that... the discussion will continue.

    Try this thinking...in a plumbing drainage pipe, water travels by gravity in the lower half of the pipe. Load calculations are done and based on the fact that water can never fill more than half. All codes accept this physical limitation. The upper half of the pipe is for....air! Without the air, the drainage water will have difficulty flowing.
    The ancient plumbing engineers figured this out thousands of years ago and they did not have degrees. Lots of people had to die from unsanitary conditions until they figured it out but... they figured it out.! So you had aqua-duct and ditch irrigation systems of Egypt and Rome capable of moving water using "open-air" technology
    (pretty advanced huh). European cities had sewers that were open to the streets where the sewage was usually dumped. But when plumbing moved indoors they had to create a different "open air" system because no one wanted to use the house as that source. They used "stacking" technology to accomplish this wildly popular phenomina known as modern in-door plumbing.

    Stacking is very simple concept. A tall vertical pipe, duct or enclosure will have have less atmospheric pressure at its top than at the bottom (very slight but enough). This allows air to flow upwards without mechanical assistance. An increase in temperature within the stack increases the upward airflow. Also the stack, as a pipe, would allow outside air to enter the piping system under a negitive pressure situation to allow for proper drainage and trap seal protection. So free ventilation both ways 24/7/365!!!! What is wrong with that??

    There is a lot more to say about the AAV but that is enough for now...What do you think?


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    Default Re: Is this an AAV or Mechanical vent

    Great bantering gentlemen. this is what makes this site so enteresting, many varied opinions...some heated and concrete in nature, but always civilizied. AAV's here in GA have been allowed for years and years and I hear of next to no issues withe them. Once in awhile I have a smell issue around a kitchen sink with an AAV...just replace it, simple task. AAV's have allowed for many, many varied kitchen and bath designs that were impossible just a few decades ago. I applaud the makers of these valves for their ingenuity. This is why our profession is sooo valuable today, we have to keep up with all the changes, varied designs of homes that complicate everything, not just plumbing. My job is so much more interesting and intellectually challenging because of all the changes. Imagine how boring our job would become if all we had to inspect were simple ranch homes. I enjoy the challenge of inspecting the new age of homes that have 5 gables in front with horrible drainage patterns off the roof, sinks in the middle of an island, bath tubs in the middle of floors, ect., ect. Keep the changes coming and I will not develop Alzheimers


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    Default Re: Is this an AAV or Mechanical vent

    Here is a link from Studor which makes an AAV, it shows which states approve and do not approve the device. As I pointed out an AAV is still considered a mechanical device, and only works with a negative pressure in the DWV system. DWV systems do have positive pressure issues which an AAV will not help with. Twelve states do not approve these and there are a handful that have a partial approval.

    Approvals by State | IPS Corporation


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    Default Re: Is this an AAV or Mechanical vent

    Quote Originally Posted by Ron Hasil View Post
    As I pointed out an AAV is still considered a mechanical device,
    And as I and others have pointed out, an AAV is not considered a mechanical device ... is most states, the code does not allow mechanical vents and AAVs are approved for use in the states which do not consider it a mechanical device.

    Jerry Peck
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    Default Re: Is this an AAV or Mechanical vent

    Quote Originally Posted by Jerry Peck View Post
    And as I and others have pointed out, an AAV is not considered a mechanical device ... is most states, the code does not allow mechanical vents and AAVs are approved for use in the states which do not consider it a mechanical device.
    There is a moving part in an AAV which makes it mechanical, also it does not help with positive pressure in the DWV system. I know many plumbers in states where an AAV is approved and used, and they run many service calls where home owners complain about a sewer odor. They track it down to the AAV valve, when it opens to allow air to enter the DWV system, odors do escape.

    But the key is the link I posted should help you home inspectors release if your state you are in allows AAV's or not. If you are in Illinois they are not allowed at all by the plumbing code.


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    Default Re: Is this an AAV or Mechanical vent

    I hope this does not turn into a debate.

    Ron
    Jerry did not state an AAV, is or is not mechanical
    he did say
    " AAVs are approved for use in the states which do not consider it a mechanical device. "

    ' correct a wise man and you gain a friend... correct a fool and he'll bloody your nose'.

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    Default Re: Is this an AAV or Mechanical vent

    Had a friend whose kitchen sink wouldn't drain last week. I unscrewed the Studor AAV and it drained. After a little while, I screwed it back in and the sink began to drain properly.

    Sufficed to say, I believe AAVs to be problematic.

    Bruce Thompson, Lic. #9199
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    Default Re: Is this an AAV or Mechanical vent

    Quote Originally Posted by JB Thompson View Post
    Had a friend whose kitchen sink wouldn't drain last week. I unscrewed the Studor AAV and it drained. After a little while, I screwed it back in and the sink began to drain properly.

    Sufficed to say, I believe AAVs to be problematic.
    AAV's need maintenance from time to time, that is why they are required to be accessible.
    When used appropriately, the problems they solve far outweigh the problems they cause.

    ' correct a wise man and you gain a friend... correct a fool and he'll bloody your nose'.

  35. #35
    Marc Albanese's Avatar
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    Default Re: Is this an AAV or Mechanical vent

    If you're interested in understanding the issues and problems with AAV's read
    on. If not...sorry and good-bye.

    "Let's take it up a notch!!" Every plumbing system
    generates sewer gases as a natural by-product of waste as I stated in an
    earlier post. Plumbing systems were designed to remove this dangerous gas
    by means of plumbing vents. By their very definition vents admitted and
    emitted air. By changing the the definition of a vent to admit OR emit
    air...presto...an aav is now a vent. Don't take my word for it... check your
    code definitions. It is not a vent if it cannot ventilate...it is a vacuum breaker.

    Also understand that dead end plumbing is prohibited. Dead end plumbing would allow excessive accumulation of dangerous sewer gases within the structure and all model codes require the removal of unused plumbing piping. When you install an aav you essentially have a dead end without air circulation. Even the "one vent pipe through the roof" requirement for aav"s will not create the circulation of air necessary to keep sewer gases from collecting in the other portions of the same plumbing system.

    We had these simple rules to maintain health and sanitary conditions. It appears
    that we have forgotten everything we learned about public health because by
    the installation of aav's on fixtures, fixture groups, and stacks we have
    people sleeping, eating, working, and playing next to floors, walls and ceilings that
    contain tall canisters (pipe) filled with hydrogen sulfide, methane and nasty smelling and noxious mercaptans because they have no place to go. And I don't buy the argument that when the valve opens it is no longer a dead end pipe because...I may
    have been born at night...but not last night!!

    This is a discussion worth having because we are inspectors and
    professionals. The acceptance and installation of an aav is not a panacea.
    It has created some new problems and, unfortunately, is perpetuating an old one that some cannot see or do not understand . Out of this collective ignorance our public health and safety is diminished.
    Please let me know how you see it.


  36. #36
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    Default Re: Is this an AAV or Mechanical vent

    Quote Originally Posted by Ron Hasil View Post
    An AAV is a mechanical vent as well. They all should be baned.... sorry I just had to rant a little.
    That was a little rant. Dennis Miller would be disappointed.


  37. #37
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    Default Re: Is this an AAV or Mechanical vent

    Quote Originally Posted by Marc Albanese View Post
    Plumbing systems were designed to remove this dangerous gas by means of plumbing vents. By their very definition vents admitted and emitted air. By changing the the definition of a vent to admit OR emit air...presto...an aav is now a vent. Don't take my word for it... check your code definitions. It is not a vent if it cannot ventilate...it is a vacuum breaker.
    Appears that someone wants to try to twist the definitions to say what they want the definitions to say and ignore what the definitions actually say.

    As you said "check your code definitions": (bold and underlining are mine)
    - DEAD END.
    A branch leading from a soil, waste or vent pipe; a building drain; or a building sewer, and terminating at a developed length of 2 feet (610 mm) or more by means of a plug, cap or other closed fitting.

    - STACK VENT.
    The extension of a soil or waste stack above the highest horizontal drain connected to the stack.

    - STACK VENTING.
    A method of venting a fixture or fixtures through the soil or waste stack.

    - VENT PIPE.
    See “Vent system.”

    - VENT STACK.
    A vertical vent pipe installed primarily for the purpose of providing circulation of air to and from any part of the drainage system.

    - VENT SYSTEM.
    A pipe or pipes installed to provide a flow of air to or from a drainage system, or to provide a circulation of air within such system to protect trap seals from siphonage and backpressure.

    With at least one vent ending open to outdoor air, the vent pipe is not a closed system and is not the equivalent of a "vacuum cleaner" as was referenced.

    With at least the one vent ending open to outdoor air, the vent system is basically as a neutral pressure to outdoor air ("basically" as there will be some minor differences and fluctuations because of wind and other things). When a fixture drains, there is a negative pressure on the vent leading from that fixture as air is being drawn into the vent system, and there is a positive pressure preceding the flow of water (caused by the slug of water and air going down the drain pipe, pushing air in front of it) which escapes out the open vent which is open to outdoor air.

    When AAVs are installed and used properly, they are reliable venting devices, when not installed or used properly, they cannot, are not designed to, make up for an improperly designed venting system.

    AAVs are not designed for, and not approved for, use on a positive pressure system or forced system, they are suitable for use on a gravity flow system.

    Some people do not like AAVs, some people do not like GFCIs (see a few electrical threads, those people would rather not see GFCIs installed to save lives instead of spoiling food, etc.); there is no discussion which can go on here which will lead to either type of person to open their mind up and think about things.



    Jerry Peck
    Construction/Litigation/Code Consultant - Retired
    www.AskCodeMan.com

  38. #38
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    Default Re: Is this an AAV or Mechanical vent

    Quote Originally Posted by JB Thompson View Post
    Had a friend whose kitchen sink wouldn't drain last week. I unscrewed the Studor AAV and it drained. After a little while, I screwed it back in and the sink began to drain properly.

    Sufficed to say, I believe AAVs to be problematic.
    I will amend my earlier comment to say that the plumbing vent system in this home was sorely lacking. The AAV was having to do more than its fair share (basically provide air for the entire system.)

    That being said, the nearest drain to which the AAV served was the kitchen sink and I was surprised that it wouldn't allow the sink to drain. I cannot fault it for desperately trying to provide air for the 2 toilets, 1 shower, 1 tub, 2 bath sinks that it was also serving.

    Bruce Thompson, Lic. #9199
    www.TylerHomeInspector.com
    Home Inspections in the Tyler and East Texas area

  39. #39
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    Default Re: Is this an AAV or Mechanical vent

    Quote Originally Posted by Rick Cantrell View Post
    AAV's need maintenance from time to time, that is why they are required to be accessible.
    When used appropriately, the problems they solve far outweigh the problems they cause.

    Thanks for that.

    Everyone talking of death and destruction here is a bit out of control. These vents, for the vast majority of uses provide a very substantial benefit. They do supply venting when needed. Vents supply venting when needed. When a studor vent goes bad ... change it out as the outcome will be very obvious. When a regular roof vent gets blocked ...l clean it out or the outcome of it being blocked will be obvious.

    Someone mentioned GFCIs in this thread. If they go bad change them out. The problem with them is that half the time you do not know they stopped working. I test GFCIs every day. Once evry week or in the worse case once every 2 weeks I find them that no longer trip and in essence are far worse than any receptacle because folks rely on them to "save their lives".

    Why is it everyone has to go the death and destruction route for any item that can possibly go bad ...... they all go bad after a while.

    If you are in need of a studor vent they are a fantastic problem solver. Like any form of mechanical/safety/death and destruction solver/electric outlet/blocked vent/flue that gets blocked or falls off/leaking heat exchanger etc etc etc etc etc .... fix the damn thing.

    Stop with the everyone is going to die and if it saves just one life etc etc etc etc etc etc for gosh sakes gents. Its a studor vent and for the most part work fine like any other device for years or even decades before it needs replacing. As in any device of any kind .... it can go bad tomorrow .... fix it. Don't fix it when it goes bad? You will find out why you should have sooner or later and for the absolute vast majority it will be a poorly draining line or a smell that you will find where it is coming from.

    Ever walk into a vacant home where the toilet bowl has dried out. Yup. Put some water in it.


  40. #40
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    Default Re: Is this an AAV or Mechanical vent

    The problem is when the AAV is on an island sink on the first floor, which the drain connects to a stack. When a large volume of water is let loose from the second floor, the slug of water as it falls is drawing air from the roof vent above, but below the slug it is causing a positive pressure The AAV does nothing for this so the kitchen sink will gurgle which is the positive pressure breaking the trap seal. This is a known problem that Studor and other AAV manufactures know about and has made another mechanical device to correct this issue.

    Illinois plumbing code is clear that a device is not to replace proper venting. AAV's are just a so called cost savings in labor and material verses installing vent piping for all the plumbing fixtures. As Marc Albanese stated many has forgotten why the plumbing codes did not allow stuff like this in the past, to protect and maintain the health of the nation.

    Let me leave you with this quote from a 1911 Ohio Plumbing code book

    Quote Originally Posted by 1911 Ohio Plumbing code
    Low First Cost Mistaken Economy

    A second class plumbing and drainage system in cost will prove itself a second class system in service. A year or so in service will reveal the inefficiency of the fixture, device or construction. Discomfort, inconvenience, cost of repairs, foul odors, insanitary and unhealthful conditions are the resulting penalties which the unfortunate occupant must pay.
    The plumbers and engineers back in 1911 knew that short cuts can cause issues, but in the name of the almighty buck we are putting in second class plumbing and DWV systems.


  41. #41
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    Default Re: Is this an AAV or Mechanical vent

    Here is a link to cheater vents like the one shown. Please note the one shown is not listed for use in homes, see link. But there are 'DRAW VENTS THAT ARE ul and csa approved for use in retro fitting homes and new construction.," also in link. http://www.muskokahomeinspection.ca/Home-cottage-commercial-inspection-cheater-vent-danger-in-Orillia-Muskoka-Midland


  42. #42
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    Default Re: Is this an AAV or Mechanical vent

    This looks like a good canidate for an AAV

    (This is a photo provided by Mathew S., from another thread)

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    ' correct a wise man and you gain a friend... correct a fool and he'll bloody your nose'.

  43. #43
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    Default Re: Is this an AAV or Mechanical vent

    Quote Originally Posted by Rick Cantrell View Post
    This looks like a good canidate for an AAV

    (This is a photo provided by Mathew S., from another thread)
    I disagree. Just because someone chose to creatively plumb the trap under that sink does not mean its not vented in the wall, and does not mean it can not be properly vented in the wall if it was not.

    I do agree that it needs to be redone properly. I have come across a few jobs where the tee in the wall was plumbed in either to high or to low. I just ended up removing the cabinet and opening the wall an putting the tee at its proper height.


  44. #44
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    Default Re: Is this an AAV or Mechanical vent

    Ron
    I don't expect to change your mind.
    You think of AAV's, like I think about wireless alarms.
    I've never seen one I like.
    But there are a few times when a wireless alarm sensor, like an AAV, is the best choice for a bad situation.

    ' correct a wise man and you gain a friend... correct a fool and he'll bloody your nose'.

  45. #45
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    Default Re: Is this an AAV or Mechanical vent

    Quote Originally Posted by Rick Cantrell View Post
    Ron
    I don't expect to change your mind.
    You think of AAV's, like I think about wireless alarms.
    I've never seen one I like.
    But there are a few times when a wireless alarm sensor, like an AAV, is the best choice for a bad situation.
    Rick in the 30 years I been doing plumbing I have yet come across a situation where I said " Man I wish Illinois would allow us to us an AAV"

    I do not like short cuts, mainly because I agree with the statement I posted from the Ohio 1911 code book. "A second class plumbing and drainage system in cost will prove itself a second class system in service."

    Here is another pert from the same book about using cheap valves.

    Inferior Stops and Valves

    A cheap grade of stop and waste cocks and valves often used in the installation of water service and upon fixtures is false economy and expensive practice. Inconvenience, annoyance, waste of water and continual repairs are the relating penalties from this practice.



  46. #46
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    Default Re: Is this an AAV or Mechanical vent

    Quote Originally Posted by Ron Hasil View Post
    Rick in the 30 years I been doing plumbing I have yet come across a situation where I said " Man I wish Illinois would allow us to us an AAV"

    I do not like short cuts, mainly because I agree with the statement I posted from the Ohio 1911 code book. "A second class plumbing and drainage system in cost will prove itself a second class system in service."

    Here is another pert from the same book about using cheap valves.
    Inferior Stops and Valves

    A cheap grade of stop and waste cocks and valves often used in the installation of water service and upon fixtures is false economy and expensive practice. Inconvenience, annoyance, waste of water and continual repairs are the relating penalties from this practice.
    Amen!


  47. #47
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    Default Re: Is this an AAV or Mechanical vent

    You sent the following:

    - DEAD END.
    A branch leading from a soil, waste or vent pipe; a building drain; or a building sewer, and terminating at a developed length of 2 feet (610 mm) or more by means of a plug, cap or other closed fitting.


    - VENT SYSTEM.
    A pipe or pipes installed to provide a flow of air to or from a drainage system, or to provide a circulation of air within such system to protect trap seals from siphonage and backpressure.


    Jerry, I assume this is the Florida Code? Doesn't really matter. This definition is for a legal dead end (no more than 2 ft.). An illegal dead end would be greater than 2 ft..
    So my point is that piping greater than 2 ft. is allowed to terminate with an aav and is now legal....but it cannot provide the circulation necessary to keep it from being a collector of sewer gas (which is why dead end piping cannot exceed 2 ft.). It just seems dysfunctional and not very honest.

    Here in New York State (very dysfunctional) the previous state code for over 50 years
    defined plumbing vents as admitting and emitting air. So you make my point. Most model codes use the "and" but the IPC has simply changed the conjunction from and to or and changed the entire function of plumbing vents. NYS has adopted the ICC plumbing code (with enhancements) so it must have been easier to change the language than the physics to allow the use aav's. Not trying to change anyone's mind just give you another perspective. Self revelation is the best revelation.


  48. #48
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    Thumbs down Re: Is this an AAV or Mechanical vent

    Tried to stay out of this.

    Every one seems to be going in circles without getting to the basic original item picture and its use/application.

    Air Admittance Valves come in to flavors, black and white. At least all that I have seen.

    There are either compliant to ASSE standard 1050 or ANSI/ASSE 1051 or they are not.

    Typically if it is packaged and stated as an AAV it is white and has the specifications of compliance on the box. Along with any other sources of specifications that actually list the specifications.

    You will see a Cheater Vent in black and packaged without any specification and not referred to as an AAV. Furthermore, if you pull up the Cheater Valve specifications you will find that there are none listed.

    One manufacture of a Cheater Valve is Watts, which shows a Model 280 ProVent Air Admittance Valve and when you go to its specification you find nothing listed. Why because it is a deception on their part for trying to get around the non compliance issue and still call it an AAV. SEE::::
    280PV ProVent Air Admittance Valve, Air Admittance Valve, Brass & Tubular - Watts

    If you go to Oatey you will see that they have an AAV with the compliance specifications listed. Model: 39016 SEE::::
    http://www.oatey.com/apps/catalog/instance_assets/assets/OAT_AAV_SVA_link3.pdf

    Now, for the Mobile Home discussion. Cheater Valve or check vent, remember that it is a mater of actual term (words ) used. Be carefull to differenciate between AAV and cheater/check valve. SEE:::

    Plumbing Check Vent | Mobile Home Repair


    So, doesn't it just boil down to state/local code requirement and allowable application.
    Which typically mandate that if used that it be accessible. Why? In case of failure. When it works it works, thus the use of compliant ASSE standards.

    Why do you find them? Boils down to money. Why use non compliant models valves? Again it money or just stupidity. Compliant ASE cost 4 times that of non compliant one.

    Many miss the point that the use in a mobile home or travel trailer is really about the type and use of the structure.

    In a house the AAV does not replace the fixed vent system but augment its use in certain applications such as an island sink.

    Sorry a little ranting as a result certain suppliers and distributors misleading the public.


  49. #49
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    Default Re: Is this an AAV or Mechanical vent

    Hello Garry, very nice post about one type of device having ASSE and ANSI approvals and the other not. At one time the mechanical (cheater) vent did have the appropriate approvals. They no longer seek out to get the mechanical (cheater) vent approved since it would be a waste of money, that nearly all plumbing codes state mechanical vents are not allowed.

    There has been many things that have gotten the appropriate approvals, and still carry them till this day for example Orangburg Pipe (bituminous fiber sewer pipe). The Orangburg pipe was widely accepted from the 1950's till the late 1970's, and in most cities, towns, counties and states have no longer approved it for use anymore. They did this because they realized there are issues with this pipe that can cost the property owner 1000's of dollars to replace. Here is a recent thread posted on this forum about the pipe.http://www.inspectionnews.net/home_i...tml#post168878

    The reason I bring this up, is the fact there where and will be things that get the appropriate approvals , and states will allow them to be used. Many of these plumbing devices, pipe and so forth eventually will be banned by the local codes. Give you another example of something that was approved is waterless urinals. Illinois allowed the city of Chicago to install these in a building as a test. A year later they where removed and the drain piping in the walls had to be replaced. Other cites are banning them as well across the country, due to the foul odor these emit, and the fact they need to have constant maintenance replacing the cartridge that makes the trap seal.

    The key is as I said in another post where I posted a link with what states approve these devices and which do not. You have to check to see if it is approved in your area and meets the local requirements for the install. The one pictured by the OP is a mechanical vent and does not meet any codes, and yes it should be an AAV if its allowed in the OP's state.

    I do feel in time AAV's will be banned in more and more areas as time goes on for them. There are 12 states that do not allow them, and 6 states that only gave a partial approval, and there are 4 states where certain cities or counties that do not allow them.


  50. #50
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    Default Re: Is this an AAV or Mechanical vent

    I am always amused at the many plumbers nationwide that have difficulty accepting new ideas. I saw the same with shark bite type fittings yet used them at many Naval Air Stations on air craft and in paint booths where an open flame was not allowed and never had a single one fail.
    Now years back, maybe 15, I heard the same thing about AAV's.
    Bad Bad Bad Bad.

    Well our firm has used them without one failure and it's because we use common sense with our use of AAV's.

    First the main line, whether it's 3-4 or 6" has to be ran full diameter through the roof, somewhere.
    This is where most plumbers fail in understanding the use of AAV's.

    If the main gut line is full size through the roof, then AAV's installed 'above the wet line of any fixture' is perfectly fine. We never install one unless it is at least 1 foot above any wet line (sink rim) and we always place all AAV's 1 foot above the highest wet line in the house/building.
    This prevents the seal from getting back washed and damaged.

    Lastly we have a screen cover we put over each AAV to prevent bugs/wasps from building nests or getting into the air valve area and stopping it from working.


    We have saved untold hours/days/dollars on projects using these AAV's and to date after 40 plus years of plumbing/HVAC/Ele/Asbestos Abatement, our firm has never had a Red Tag or a failed install.

    CYa
    They do indeed work if one does it right.


  51. #51
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    Default Re: Is this an AAV or Mechanical vent

    Quote Originally Posted by Doc Haley View Post
    I am always amused at the many plumbers nationwide that have difficulty accepting new ideas. I saw the same with shark bite type fittings yet used them at many Naval Air Stations on air craft and in paint booths where an open flame was not allowed and never had a single one fail.
    You are aware that SharkBite fittings are not approved for electrical conductivity through them, thus when used on copper or other metallic piping the SharkBite fittings need to be bonded around.

    We have saved untold hours/days/dollars on projects using these AAV's and to date after 40 plus years of plumbing/HVAC/Ele/Asbestos Abatement, our firm has never had a Red Tag or a failed install.


    I realize you are referring to AAVs with the above, but, with the SharkBite fittings ... you would likely "never know of a failure" unless you happened to be the one the failure happened to ... and the "leakage" I am referring to is not liquid, and the "failure" is not "leakage", it is the loss of continuity through the SharkBite fitting.

    Most plumbers do not consider the electrical continuity through SharkBite fittings because they are "plumbers" and not "electricians", and it is the electricians grounding/bonding path which is being broken (are at least the grounding/bonding path is 'not being preserved by a fitting listed for that use').

    Jerry Peck
    Construction/Litigation/Code Consultant - Retired
    www.AskCodeMan.com

  52. #52
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    Default Re: Is this an AAV or Mechanical vent

    I don't assume, and haven't for decades, that a plumbing system is adequate for the electrical system grounding any longer. It has it's faults/dangers too, especially with the failure of people in not using or having GFCI's decades back.

    Therefore, our electricians run #4 ground from all systems back to the 8 foot copper grounding rod along with the main breaker box's ground wire. We ground the plumbing equipment to this same rod in the ground that our electricians use.

    Got my plumbing license in the 70's yet owned a plumbing company in 1972 before I got my license. Am retired but still have my license some 45 years later, just because it was my first.

    Back the 40's-50's there were antiquated electrical systems. Some as old and odd as wooden spools in attics that wiring was wrapped around and ran 'open' where a person could be come dead by crawling around attics. Grounding was very necessary since the electrical system did not have it inherently, so the copper piping was chosen to be the carrier.

    With the two wire system the electricians relied upon the copper piping to be their universal ground.

    With the three wire system (black/white/ground), better yet the three wire system with ground (black/white/red/ground), systems became safer and we only relied on the copper piping to ground plumbing equipment, not the electrical systems.

    We have been using 8' copper, half inch diameter, rods for decades.

    AAV's installed on an outside wall in a vented access box, or in the attic space where they remain accessible, in our experience have never failed. We screen them for bugs and they are high enough to never be affected by a backed up sewer system. These two items (bugs and installed too low are the human errors that cause them to fail).

    These AAV's need to be checked yearly just like the water heaters need to be flushed every year. Yet we all know homeowners never flush their water heaters.

    Cya


  53. #53
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    Default Re: Is this an AAV or Mechanical vent

    Quote Originally Posted by Rick Cantrell View Post
    AAV's need maintenance from time to time, that is why they are required to be accessible.
    When used appropriately, the problems they solve far outweigh the problems they cause.
    Here is what Studor say about their AAV's.
    "As long as they have been installed in accordance with our installation instructions, are protected from building dust, and have free movement of air, no maintenance is required." They do not mention how to maintenance them.
    Thanks.

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