Air inlet valves are mechanical devices that replace sanitary openings. They are inexpensive, they work, they can reduce the number of plumbing vents on the roof, they are not blocked by frost, they are listed and approved by several registration agencies, and they cost much less than plumbing. In any case, they are not legal here in Minnesota. Air intake valves (AVAs) are disposable air valves installed under a drain that allow the required fresh air to flow into sewer pipes to prevent sewer gases from escaping into the building. Using a combination of AAV Studor/IPS and its 2-way “Maxi-Filtra” charcoal filtered vent instead of an outdoor duct cleaning cap, we eliminated all sewer pipe vents. The Maxi-Filtra is a two-way air valve outside the house with an activated carbon filter that allows overpressure in the sewer system to escape odorlessly into the atmosphere. When we built our house in 1998, it exceeded the building`s energy needs. However, in 2009, we woke up to the threat of global warming and knew we had to adapt our home to the Passive House standard, a super-insulated design strategy imported from Germany. Although our home was relatively airtight (about 3.5 ACH), we knew we had to be much tighter to meet the standard (0.6 ACH). In addition to reducing air leakage, we needed to minimize or eliminate uninsulated or underinsulated assemblies in the thermal housing (for example, thermal defects). Air inlet valves are just one of the many strategies and code innovations we`ve used to prepare our home for the future.
See also refrigerant heat pump water heater, highly efficient HRV without UL-LIsting and evacuation of air from the kitchen by continuous ventilation. An AAV can replace conventional sanitary ventilation on individual fittings because it allows air to enter the drain without allowing sewer gases to enter the building. The following diagram, provided by Oatey, shows how air inlet valves can replace vents. Another problem with an air intake valve is that it could leak if there is a backflow of sewage. This is a legitimate concern, so I tried to test a number of AVAs to see if I could scare them away. I installed a sink in my garage and clogged the drain and released the water. No leaks. I even turned the air vents upside down, and nothing leaked. The problem with air inlet valves is that they rest on a mechanical seal that can eventually fail.
Nevertheless, some manufacturers, such as Sioux Chief, offer a lifetime warranty on their air intake valves. Studor offers a 10-year warranty and claims a lifespan of 500,000 cycles. Our old homemade plumbing code explicitly prohibited the use of air intake valves (AVAs), but the new plumbing code, adopted in 2016, is silent on the subject, which means the same thing. AVAs are not allowed. If I remember correctly, there was some confusion about it in 2004 (?), and there was a loophole in the plumbing code that made them legal for maybe a month or two, but it didn`t last long. If you are reading this and know the exact details, please leave a comment. Oregon`s specialty plumbing code requires air hoses that extend and end vertically above the roof. However, in 2007, Studor, Inc., the world`s largest manufacturer of AAV, sought a decision to allow AVAs in Oregon homes. In 2007, the Oregon Division of Building Codes issued Judgment No. 07-1, which approved air intake valves, subject to a number of restrictions and restrictions. However, these limits did not comply with Studor`s installation guidelines and made the use of AAVs virtually impossible. For example, the decision limited each AAV to serving only one plumbing fixture and the total number of AAVs to three per home.
A single bathroom could use the entire allowance. In addition, Oregon maintained the passage ventilation requirement. Portland`s approval by ITAC eliminated these limits and the transit requirement. I sometimes meet them during home inspections, and I have no problem with them. When I find an air intake valve, I let my client know that it is not allowed in Minnesota. This will likely result in additional costs if someone has authorized plumbing in their home, and that`s the main reason I mention it. In order to protect the joints from sanitary traps, the sanitary openings also allow the ventilation of pressurized wastewater gases to the outside. For this reason, at least full-size sanitary vents should always be installed in every house, whether air intake valves are installed or not. In conventional homes, through vents provide the exhaust side of the plumbing system, but they also allow cold winter outdoor air to sink into the (usually uninsulated) ventilation pipes in the home. This is a huge thermal defect! In addition, the air hoses pass through holes in the top plates, which are difficult to seal tightly, leading to more air leakage and heat loss. Air inlet valves (AVAs) perform the same function as vents by allowing additional air to enter the waste pipes without the energy losses of the canopy piping.
An AAV can provide makeup air for drains from more than one faucet, for example, an AAV can serve all the fixtures in a bathroom. We reduced air leakage and thermal bridges by replacing our plumbing system with a combination of air intake valves (AVAs) and a two-sided filtered external valve. Oregon`s plumbing code recognized AVAs, but limited their use to 3 per home and required ventilation. On appeal, the City of Portland allowed us to install AVAs in accordance with the manufacturer`s guidelines to eliminate all continuous vents using the “alternative materials and methods” designation through the Alternative Technology Advisory Committee (ITAC) process. The manufacturer`s representative helped me learn about sewage systems. I learned that while AVAs allow auxiliary air to enter sewer lines, they themselves do not provide the ventilation required for the “overpressure” that can occur in homes connected to municipal sewer systems and that could cause sewer gas to flow into a home.
