Historical
ANSI/ASSE 1012-2009
Performance Requirements for Backflow Preventers with an Intermediate Atmospheric Vent
The devices covered by this standard are those which have functional capabilities for preventing both back-siphonage and back pressure and which can operate under continuous or intermittent pressure conditions. These devices have 2 independently operating check valves separated by an intermediate chamber with a means for automatically venting it to the atmosphere and can be installed in the horizontal, vertical up or vertical down orientations. The check valves are force loaded to a normally closed position and the venting means is force loaded to a normally open position.
Content Provider
American Society of Sanitary Engineering [asse-sanitary]