ASSE (Plumbing) 1047-2011

The purpose of a Reduced Pressure Detector Fire Protection Backflow Prevention Assembly is to keep contaminated water from fire protection systems from flowing back into a potable water distribution system when some abnormality in the system causes the pressure to be temporarily higher in the contaminated part of the system than in the potable water supply piping. These assemblies are designed to detect low rates of flow up to 2.00 GPM (0.13 L/s) caused by leakage or unauthorized use.

This standards applies to Reduced Pressure Detector Assemblies (RPDA) and Reduced Pressure Detector Assemblies Type II (RPDA-II). The RPDA and RPDA-II assemblies consist of two (2) independently acting check valves, internally force loaded to a normally closed position, and separated by an intermediate chamber (or zone) in which there is a hydraulically operated relief means for venting to atmosphere, internally force loaded to a normally open position. These assemblies are designed to operate under continuous pressure conditions. The assembly shall include two (2) properly located, tightly closing shut-off valves and properly located test cocks. The assemblies also include a bypass line which provides a visual or audible indication of system leakage or unauthorized use of water. This standard also applies to Manifold Reduced Pressure Detector Assemblies consisting of two (2) or more complete RPDA or RPDA-II assemblies in parallel.