New guidance helps clarify use of domestic air admittance valves

Correct positioning of an AAV

The BPF Pipes Group has just launched new guidance on domestic air admittance valves (AAV) for those working within the plumbing sector in the UK.

The document provides clear advice on how to position air admittance valves correctly, as well as highlighting the different regulations currently in place across England, Wales, Scotland and Northern Ireland.

Air admittance valves are used to ventilate soil and waste pipes so that waste water drains properly from a property.  Without ventilation, air pressure changes inside the pipework due to the operation of domestic appliances would cause waste traps on those appliances to lose their water seals, creating unpleasant odours.  Traditionally, open soil stacks have been positioned above the roofs of properties but can be damaged or accidentally covered, for example when extensions are built.  Air admittance valves, positioned inside the roof space, provide a more aesthetically attractive alternative to open stacks whilst providing the same level of ventilation.

The BPF Pipes Group document provides a detailed guide to the current regulations on soil stacks and air admittance valves, as well as operation, ventilation, capacity, ratings and location.  A building control checklist is also provided to help those installing such devices in domestic properties.

Steve Skeldon is Chair of the BPF Pipes Group’s working group on soil and waste, and he commented: “Air admittance valves have been in use for over 40 years and provide a functional and more aesthetically pleasing alternative to open soil stacks, as they are positioned inside roof voids.  We want this new guidance to provide a definitive aid to those working in plumbing and venting drainage systems for both new build and refurbishment projects.”

The guidance is available online or as a downloadable PDF from the BPF Pipes Group website at it joins a growing reference base for those working with plastic pipe systems.

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