standard published 2004 by American Society of Sanitary Engineering
This standard establishes design and performance requirements and test procedures for Dual Check Backflow Preventer Wall Hydrants - Freeze Resistant. The purpose of these devices is to provide protection of the potable water supply from contamination due to backsiphonage or backpressure without damage to the device due to freezing, and is field testable to verify protection under the high hazard conditions present at a hose threaded outlet. This device shall only be used on systems where the low-head backpressure does not exceed that generated by an elevated hose equal to or less than 10.0 feet (3.0 m) in height, and are not subjected to continuous water pressure.
