ASSE (PLUMBING) 1019-2011 Performance Requirements for Wall Hydrants with Backflow Protection and Freeze Resistance
: Brown Technical Book Store
These devices shall have a permanent means to protect against backflow due to either backsiphonage or backpressure. The backflow protection shall include a minimum of two (2) mechanisms: an air inlet for preventing backsiphonage and a check valve for preventing backpressure backflow. These devices are terminal fittings that supply potable water to hose connections without danger of freezing.