What is the minimum height for an air admittance valve?

Author: Ethelyn Dietrich  |  Last update: Saturday, July 5, 2025

AAV location It must be located a minimum of 4” above the horizontal branch drain, 6” above any insulation material and within 15 degrees of vertical. AAVs cannot be permanently covered and should be installed in an area that allows air to enter the valve.

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.

How low can an air admittance valve be?

How high should you install the air admittance valve? 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.

What are the rules for air admittance valves?

Individual and branch-type air admittance valves shall vent only fixtures that are on the same floor level and connect to a horizontal branch drain. Individual and branch air admittance valves shall be located not less than 4 inches (102 mm) above the horizontal branch drain or fixture drain being vented.

How high does a studor vent have to be?

The Studor valve must be installed a minimum of 4" above the horizontal branch the horizontal branch drain or fixture drain being vented. Studor AAVs must be installed within 15 degrees of the vertical position. Studor valves can be installed below the flood rim level of the fixture.

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

What is the minimum height for air vents?

Vents shall terminate not less than 5 feet (1524 mm) in vertical height above the highest connected appliance flue collar. Exceptions: Venting systems of direct vent appliances shall be installed in accordance with the appliance and the vent manufacturer's instructions.

Why is Studor vent illegal?

The Studor vent lets that air to be sucked in the pipe during water flow but doesn't let sewer gas escape out. 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.

How high should an internal air admittance valve be installed?

The external soil stack may be terminated below the roofline which reduces the amount of soil pipe and fittings required. The AAV may be installed at a minimum height of 200mm above the highest wet branch connection.

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.

How high should AAV be above trap?

AAV location

It must be located a minimum of 4” above the horizontal branch drain, 6” above any insulation material and within 15 degrees of vertical. AAVs cannot be permanently covered and should be installed in an area that allows air to enter the valve.

Where should I place my air admittance valve?

The AAV should be located a minimum of four inches above the horizontal branch wall tube. » Securing AAV: Measure and cut the PVC pipe appropriately. Solvent-weld the pipe into the adaptor using PVC cement, such as the Oatey® Heavy Duty Clear PVC Cement, which can be used for all PVC pipe and fittings.

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 is the best alternative to a soil vent pipe?

An air admittance valve (AAV) is an alternative option to fitting a vent in a soil pipe – a soil pipe vent if you will. It opens automatically when water enters the soil pipe and closes when the water has passed into the drain.

Does an air admittance valve go before or after a trap?

Air Admittance Valves (AAV) are one-way vents installed after the trap on the drain line of a fixture. They're designed to address negative air pressure in the drain system, created when a fixture is drained.

What is the minimum height of vent riser?

Vent and branch vent pipes shall be free from drops and sags and be sloped and connected so as to drain by gravity to the drainage system. Every vent shall rise vertically to a minimum of 6 inches above the flood level of the rim of the fixture being served.

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.

Does an air admittance valve stop smells?

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 happens if a soil pipe is not vented?

Foul Odours and Health Concerns

If a soil vent pipe becomes blocked or damaged, foul odours from trapped gases can infiltrate living spaces.

How high does a vent pipe need to be above the roof?

Extensions of vent pipes through a roof shall be terminated at least 2 feet above the roof surface and shall be properly flashed. Where the roof is used for any purpose other than weather protection, the vent pipe shall extend at least 7 feet above the roof surface and shall be properly supported.

Can I box in an air admittance valve?

Where an AAV is enclosed in a boxing the boxing should be ventilated. The use of ventilation grilles, discreet gaps around the boxing or ventilation of the boxing into a ventilated roof void are some acceptable methods of providing ventilation.

Can you use an AAV to vent a toilet?

Air admittance valves are a practical option for venting toilets, but it's crucial to follow local rules.

What is the minimum height of a branch vent above the fixture it is venting?

The vent or branch vent for multiple island fixture vents shall extend not less than 6 inches (152 mm) above the highest island fixture being vented before connecting to the outside vent terminal.

What height should AAV be installed?

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.

Is an air admittance valve the same as 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.

Where should an AAV be installed?

The AAV should be located: Within the maximum developed length permitted for the vent. A minimum of 4 inches above the horizontal branch drain.

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