Air Admittance Valves (AAVs) are used to vent sewer gases and allow for proper air pressure within the plumbing system. They can be a great option when roof penetration is not preferred and allow for ventilation where piping is hard to install.

But how do you choose the right Air Admittance Valve for the job?

In this guide, we’ll share what the Australian & New Zealand standards state and other key features you need to know before buying one.

Regulations in Australia

In Australia and New Zealand, there are essential plumbing code standards that must be complied with. Air Admittance Valves (AAVs) have their own installation requirements and prohibited scenarios where they cannot be used.

So what do the standards say for choosing the right AAV?

When selecting an Air Admittance Valve, it’s essential that the Airflow Capacity of the AAV will suit the loading of the discharge pipe. The AS/NZS 3500.2 provides tables on the minimum AAV Airflow Capacity (L/s) required based on the Fixture Unit loading of the discharge pipe. If you are fitting AAVs to the connecting branches and stacks, the AAVs should have a combined airflow rating greater than the requirement of the total stack fixture unit loading. (Reference: AS/NZS 3500.2 6.10.2)

We recommend reading the latest version of the AS/NZS 3500.2 standards for more information on the requirements of AAVs, standards for installation and to calculate the required minimum determined airflow capacity needed.

Above: The minimum determined airflow capacity of air admittance valves when used as a trap vent, group vent or branch drain vent. This table has been adapted from AS/NZS 3500.2:2020 Table 6.10.2(A).

Above: The minimum determined airflow capacity of air admittance valves when used as a trap vent, group vent or branch drain vent. This table has been adapted from AS/NZS 3500.2:2020 Table 6.10.2(A).

Air Admittance Valve: 5 Selection Tips

#1 Usage

How are you planning to use the air admittance valve? Different-sized AAVs are designed for different applications. If you’re planning to use an AAV as a stack vent, you’ll generally need a larger-sized AAV with a higher airflow capacity.

#2 Fixture Units (FU) and Airflow Capacity (L/s)

You’ll need to know the Fixture Unit (FU) loading of the discharge pipe to determine the minimum Airflow Capacity (L/s) required. Air admittance valves usually specify the maximum fixture unit it can be used with as well as the determined airflow capacity.

#3 Connection

Check the diameter (mm) of the pipe and make sure the air admittance valve is suitable for the size of the pipe it is being installed on. You’ll also need to know if you’re connecting to a solvent wild pipe or a push-fit pipe, as some AAVs aren’t compatible with all connections.

#4 Chemical Resistance

If the plumbing system vents waste with chemicals present, the AAV should be compatible with these chemicals. AAVs specifically designed for laboratory chemical and grease waste pipe systems may be used for these wastes.

#5 AAV Features

AAVs may come with other speciality features. For example, some AAVs can be fire retardant and some can handle more extreme temperatures.

Bromic AAVs Compared

Bromic’s Air Admittance Valve with Adaptor for 32-40-50mm is great for use as a trap vent to prevent water loss from trap seals. With the included adaptor, it can also be used on branch discharge pipes up with the 50mm connection.

For discharge stacks up to 45 metres, the Bromic Air Admittance Valve 110mm is a great choice thanks to its high airflow capacity. This valve can connect to 110mm push-fit connections and 82mm solvent cement connections.

Where to Buy

Bromic’s Air Admittance Valves can be purchased at many plumbing supply stores across Australia. Contact your local supply store to find out if the product you’re looking for is in stock.

Available at:

• Tradelink
• Plumber’s Co-Op
• Swan
• Ace Gutters
• Plumbing Plus
• Eagle
• Mayn Plumbing Supplies
• Sydney Plumbing Supplies
• K&R Plumbing Supplies