Why are studor vents illegal?

Author: Mrs. Haylie Bartell IV  |  Last update: Saturday, August 2, 2025

Code is the thing that determines pipe size and also water flow. Hence no studor vents are permitted to toilets because more air is required to keep water flow going with more waste added to the toilet.

What is the downside of the air admittance valve?

The other potential problem with using an AAV instead of a vent pipe is that if you ever get a blockage in the system that prevents the gasses from being pushed down into the sewer, those gases will have nowhere else to go.

Where are air admittance valves not allowed?

Air admittance valves are not permitted in spaces where pressure conditions adversely affect the valve's operation. They are also not allowed in concealed wall and ceiling spaces used as plenums as part of an air distribution system that is under negative or positive pressure.

When can you use a Studor vent?

Studor AAVs are designed to open when negative pressure occurs from plumbing fixtures discharging, allowing air into the system and preventing siphonage of the trap seal. It is designed to close by gravity when there is no flow into the system, which prevents the escape of sewer gas into the building.

What is the purpose of the studor mini vent?

The unique design of the STUDOR MINI-VENT provides plumbing ventilation to prevent the loss of water seals in traps without the need for costly roof penetration and vent piping.

Air admittance valves for plumbing venting explained, [just over 4 minutes]

Is a Studor vent legal?

Some state and local building departments prohibit Studer vents. check with the local AHJ (Authority Having Jurisdiction) for more information. Studer vents are certified to reliably. However, anything mechanical can and will fail.

Where should a Studor vent be installed?

Q:The Installation Guide states: "The REDI‐VENT® must be installed in a vertical position on a minimum of 4” above the horizontal branch drain or fixture drain being vented (see Fig.

Does an air admittance valve stop smelling?

Air admittance valves often feature rubber seals, to help create a complete seal, increasing the effectiveness of the valve and preventing any odours from escaping through small gaps.

What is another name for a Studor vent?

An Air Admittance Valve (AAV), which you may also hear referred to as a Studor Vent, Studor AAV or Mini Vent, is a one-way mechanical valve that is installed locally at the site of a plumbing fixture, allowing proper venting to occur without a connection to a larger venting system and stack vent.

How to tell if Studor vent is bad?

Signs of that the Sure-Vent is not operating as intended, are foul odors. If you smell foul odors (sewer smell) near a plumbing fixture which has a Sure-Vent installed, this means the Sure-Vent is not closing properly to create a positive seal and should be replaced.

What is the life expectancy of an air admittance valve?

Air admittance valves have a typical life expectancy of 20-30 years, so if you start to have issues with sewer gases or smells being released around your sink or in the attic-wherever installed- the air admittance valve could be faulty or failed and should be replaced as soon as possible.

What are the rules for air admittance valves?

The short answer is a minimum of 200mm above any water entry point. So if you imagine your soil pipe run, then durgo valve / AAV must be fitted above the highest connection to the soil pipe from any sink, bath or toilet that is connected to it.

Does an air admittance valve replace a vent?

Air Admittance Valves (AAV) — Oatey ®Sure-Vents® — are mechanical devices installed to a plumbing fixture, replacing a secondary vent. These valves allow one-way ventilation, removing the need to connect to an existing venting system or run a separate, potentially unsightly ventilation system.

Are Studor vents reliable?

AAVs are certified to reliably. However, anything mechanical can and will fail.

How often does AAV fail?

While this is rare, it is possible. Remember that these valves should last anywhere from 20 to 30 years, so if they are only lasting for a couple of years, there may be some problems that need addressing.

How high does a Studor vent need to be?

It must be located a minimum of 4” above the horizontal branch drain, 6” above any insulation material and within 15 degrees of vertical.

In what states are air admittance valves legal?

They are not illegal in California as a state because California Plumbing Code allows "Engineered Vent Systems" see Section 911.0.

Who invented the Studor vent?

Sture Ericson developed the air admittance valve (AAV) in Sweden in the early 1970s. He introduced the valve to the United States in 1986 and was instrumental in the development of the ASSE Performance Standards 1050 and 1051, as well as gaining code approvals in state and model codes. In 1988, Studor, Inc.

What happens if a sink drain is not vented?

Sewer Gases

In addition to these issues, improper venting of a sink drain can also lead to more serious problems, such as sewer gas leaks. Sewer gas is a mixture of toxic and non-toxic gases that are produced by the breakdown of waste materials.

What is the problem with the air admittance valve?

Yes, there are some occasions when a Durgo / air admittance valve failure is possible. They include a) the valve may get stuck and need lubricant to be applied, b) the valve was installed poorly or in the wrong position, or c) the waste pipe is blocked and gases aren't being pushed down properly.

Why do I smell sewage through my vents?

There are a few reasons why sewage smells could come from your HVAC system. In most cases, it's a clogged filter or drain line. Filters prevent pollutants from entering your home, so they cause a nasty odor when they become clogged. A blocked drain line can push odors into your home.

What is the minimum height for AAV?

The stack-type AAV shall be located not less than 6 inches (152 mm) above the flood level rim of the highest fixture being vented. The AAV shall be located within the maximum developed length permitted for the vent.

Why do you need a Studor vent?

The Studor Air Admittance Valve (AAV) is a one-way valve that allows air to enter the plumbing drainage system when fixtures discharge. The valve closes by gravity when discharge is completed and under no flow conditions preventing sewer gas from escaping into the valve.

How does a cheater vent work?

How an AAV works: When a plumbing fixture is operated, negative pressure causes the AAV to open, allowing air to enter and equalize the pressure in the system. When the water flow stops, gravity closes the valve preventing sewer gas from escaping through the valve into the building.

Can you bury a Studor vent in the wall?

Each AAV has to be accessible and have unimpeded airflow, so it can't be sealed inside a wall.

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