Air Admittance Valve

  Datasheet (PDF)

The Georg Fischer Silenta air admittance valve provides reliable, localized hydraulic ventilation for non-pressurized soil and waste drainage stacks across modern building technology installations. Engineered to balance pressure fluctuations within domestic and commercial gravity wastewater networks, the valve operates via a precision one-way sealing mechanism that activates automatically under negative pressure conditions. As discharging wastewater creates transient vacuum forces within vertical drainage stacks or extended horizontal fixture branches, the internal sealing diaphragm opens instantaneously to admit ambient air into the piping network. This intake neutralizes vacuum pressure, effectively safeguarding water trap seals against siphonage and preventing sewer gas evacuation through dry traps into living spaces. Upon pressure equalization or under static and positive pressure conditions, the internal closure element drops back onto its elastomer seating by gravity, forming an airtight barrier that prevents foul sewer odors, harmful gases, and contaminated moisture from migrating back into the building interior. Fully compatible with the acoustic soil and waste product families within the Georg Fischer Silenta range, this ventilation component supports direct push-fit assembly across pipe sizes DN 40, DN 50, DN 75, and DN 110. By enabling effective venting directly within service shafts, false ceilings, and internal wall recesses, the device eliminates the requirement for costly roof penetrations, safeguarding the building envelope against thermal bridging and rainwater leakage while reducing installation complexity in multi-storey residential, commercial, hospitality, and healthcare environments.