Studor confirms that air-admittance valves can be installed externally
Studor has responded to market confusion about air-admittance valves for drainage systems and whether they can be used externally positively. Technical director Steve White says, ‘Both our own Studor Maxi-Vent and the Wavin-branded Osmavent 110 can all be used externally. The latest BBA Agrément Certificates clearly state this and specifically refer to their external use.’
The BBA certificates verify that the AI-rated valves perform in extreme temperatures, from -20 to +60°C in accordance with EN12380. However, the independent testing carried out exceeded the requirements of the standard and proved that the valves operate in temperatures down to -40°C without the insulating cap. In addition, the ABS plastic of which the valves are made includes a UV stabiliser to protect against degradation effected from ultra-violet radiation.
The certificates note that these external AAVs should be installed with the aluminium cover and insulating cap which fits on top of the valve to protect the unit from birds, wildlife and accidental damage. The cover can be purchased separately and painted if there is a need to match a particular RAL colour.
Using an AAV externally allows a vent pipe to be terminated close to a window or other opening, so there is no need for additional pipework to locate it further away.