Why is it important to allow air circulation in a buildings plumbing system?

Air circulation allows trap seals to work properly. Without ventilation negative pressure would result in the siphonage of the water seal from the trap. (Look under your sink where the pipes form a U-shape - thats a trap seal.) The trap seals form a water barrier that prevents sewer gases from entering the building - gravity and air pressure create a simple solution that has been working well for decades! Top Q2. What is new about the AAV? In the past, open vent piping was the only answer to maintaining pressure control and trap seals - the pipes extended through the roof of the building to admit air. The range offers an alternative to installing an expensive piping system for plumbing ventilation by making it possible to utilize air within the building. Top Q3. How new is this technology? Is it proven effective? The Studor AAV has been installed in millions of installations worldwide since the 1970s. The valves are tested to AI within European Standard EN12380:2002 - the highest ...  more