How high should an internal air admittance valve be installed?

Author: Ayana Rice  |  Last update: Saturday, March 22, 2025

Air admittance valve installation height The short answer is a minimum of 200mm above any water entry point.

How high should an air admittance valve be?

Air Admittance Valve in a Stack Application (ASSE 1050)

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.

Where is the proper placement of the air admittance valve?

AAV location

An AAV should be located within the maximum developed length permitted for the vent. It must be located a minimum of 4” above the horizontal branch drain, 6” above any insulation material and within 15 degrees of vertical.

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.

What height should a studor vent be installed?

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]

Where do you put a studor mini vent?

The MINI-VENT shall be located a minimum of 4” above the horizontal branch drain or fixture drain being vented and a minimum of 6” above the flood level of the highest fixture for stack venting. B. Each valve should be installed in an accessible location.

Does the AAV go before or after the trap?

Air admittance valves are typically placed between the P-trap of a fixture and the drain line. They're usually mounted on one leg of a sanitary tee, with the other leg going to the drain. The unit must be placed per local codes and the manufacturer's instructions.

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.

Can air admittance valves be installed inside?

Air admittance valves are most commonly installed inside a property and are designed for this. Having said that, some air admittance valves are designed for outside use.

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.

Do air admittance valves need to be vertical?

» AAV plumbing valve placement: AAV plumbing valve placement must be installed vertically with no more than a 15° angle, remaining as level as possible. In addition, make sure the AAV is not permanently covered and is installed where air can freely enter the valve.

Does AAV need to be above sink drain?

To work properly, the bottom edge of the AAV needs to be at least 4 inches above the top of the drain trap.

How long do AAV valves last?

AAVs are certified to reliably. However, anything mechanical can and will fail. Some manufacturers claim they're suitable for 500,000 uses (approximately 30 years). US manufacturers offer warranties that range from 1 year to “lifetime.” You'll want to seek out the warranty info.

Can you oversize an air admittance valve?

Five DFUs for the bathroom group, three for the washing machine and one for the laundry tub. This example needs an AAV of at least nine DFUs. It is acceptable to oversize an AAV; however, an undersized AAV will not allow the plumbing system to breathe properly.

How high should an under sink vent be?

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.

What is the difference between an air admittance valve and a cheater vent?

Automatic air vents are spring type devices often referred to as in-line or cheater vents, while air admittance valves have no spring. Air admittance valves are more expensive and are approved in many jurisdictions where in-line and cheater vents are not because of their moving parts (springs).

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.

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.

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.

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 to tell if AAV is failing?

To see if the AAV is working properly, take the valve off and shake - if you shake hard enough you should hear the diaphragm rattling. If you hear no noise the AAV may have failed. Additionally, smelling sewer gas is another sign that the AAV has failed in the open position.

How high does a soil stack need to be?

If the soil pipe is less than 3m from a window, ensure that the vent sits at least 900mm above said window or opening. You will also need to make sure that the soil pipe sits a minimum of 200mm above the highest water entry point (aka the highest point where wastewater will reach within a soil pipe).

Can all drains tie into one vent?

A horizontal wet vent could have as few as two fixtures or as many as ten fixtures but not more than two fixtures of any type can be connected to the system. Each wet vented fixture drain shall connect independently to the horizontal wet vent.

Do air admittance valves stink?

Yes. Any AAV can malfunction or not operate properly because it is a mechanical device. Signs of that the Sure-Vent is not operating as intended, are foul odors.

Can water come out of an air admittance valve?

In order for a liquid to come out, air must come in. All DWV plumbing systems require at least one vent penetration through the roof line, which allows air to enter the system, while also permitting sewer gas to escape.

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