The Air Valve

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It is quite normal for the air pressure inside a domestic drain system to fluctuate, so the air admittance valve was designed to let air in and out of a system as negative pressures happen. The air admittance valve can be fitted by Harrow Plumbers. The Document (H) of The Building Regulations 2000 (2002 edition) demands that air admittance valves are compliant with BS EN 12380:2002. If a drainage system has a partial blockage or there is a dipped section of pipe, then air can become trapped between the water coming in and the water that is stood inside the pipe which can result in it being forced up through a water trap on a shower, sink, bath or toilet. There is a spring loaded admittance valve (AAV) that will open and release air from the system as required but stays closed and air tight most of the time to stop internal venting, these valves can also be employed in en suite bathrooms and extra washrooms where it is not possible to connect to the existing soil vent pipework or install a new one. A Harrow Plumber is trained to fit all types of valves. These air admittance valves (AAVs) can be found in a varied range of sizes and sometimes the main waste drainage stack can be fitted with the air admittance valve. These valves are generally used when two soil stacks exist in the same building, or where there are a number of buildings that close to each other, the valve makes it unnecessary to route the highest point of the soil discharge stack out through the roof. The air admittance valve is best to be installed above the critical level for any spillages of an appliance. If one of these valves is not fitted in an awkward location and a blockage happens it would back up and the valve would lose its water tight integrity. As long as the valve is well insulated it can be fitted in exposed locations like lofts.

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