product-range

External Air Admittance Valve (AAV) Installation

The BBA Approved ByStudor External AAV Kit for Outside Use

In addition to the Handi-Vent 4 for internal installation (CE marked and AII rated in accordance with EN12380), the ByStudor range of products also includes the External AAV kit, which comprises of the AI rated Maxi-Vent AAV and an Aluminium Cover – an approved solution where an external Air Admittance Valve is needed.


Part H of the Building Regulations 2010 (clause 1.33) states that “Air admittance valves should not be used outside buildings…” Reasons for this include:

  • Temperature
  • UV degradation
  • Animals/birds/insects
  • Debris

When installed in conjunction with the Aluminium Cover, the Studor Maxi-Vent* is The ByStudor External Air Admittance Valve Kitcertified by the BBA as being suitable for internal AND external installation. This BBA approval will satisfy Building Control! AI rated (-20°C to +60°C), even without the insulating cap or aluminium cover, the Maxi-Vent is independently verified to operate right down to -40°C!

For added protection against UV degradation, the Maxi-Vent is manufactured with a UV stabiliser,and its design incorporates internal and external screening as a barrier to the ingress of debris, animals, insects and birds.

Maintenance free, and provided with a lifetime guarantee, the Maxi-Vent really is the only choice for an external Air Admittance Valve.


As Part H of the Building Regulations 2010 does not approve external use, a specific third party approval (such as the BBA) is required.

Any Air Admittance Valve marketed for external use must be supported accordingly with an approval which specifically states that that specific model of the product may be installed outside.

If the third party certificate doesn’t list the specific model, and doesn’t specifically state for “external” or “outside” use, then it’s not Part H compliant and installing it would risk rejection by Building Control.


If you need an external Air Admittance Valve (AAV) then don’t risk running foul of Building Control – get it right first time by installing the approved ByStudor External AAV kit!


Our ventilation drainage product range includes:

Handi-Vent 4 – a compact, high functioning AAV for drainage ventilation.
External AAV kit – an AI rated AAV with an Aluminium Cover – approved for external installation.
Trap-Vent – a combined trap and AAV for group venting with a compact design.
Tec-Vent – a specialist flame retardant AAV.
Maxi-Filtra – a practical two-way vent for external drainage systems and septic tanks.

For further information about our plumbing AAVs and external plumbing vent products, please refer to our product guides and instruction sheets, contact us today, or visit Studor’s website.*

*not including the Handi-Vent 4