The Principle Operation of a Pressure Vacuum Breaker Backflow Prevention Device Assembly – Typical Installations
The PVB is used for outdoor agriculture and irrigation cross-connections situations and can be use indoors with proper drainage considerations for industrial cross-connection applications. The PVB shall be installed vertically upright and plumb, accessible for testing and repair, protected from weather, vandalism or theft, installed in high visibility areas, and protect against freezing. PVB shall not be installed in pits or vaults. To operate properly the air inlet should be no be obstructed. PVB shall be installed to allow atmospheric pressure to enter the bonnet unobstructed. Rags, towels, or insulation shall not cover the atmospheric opening of the PVB. The PVB can be used when there is more than one downstream zone with shut-off valves. The PVB is used to isolate a cross-connection such as a lawn irrigation system, which are considered high hazard systems. The PVB is not designed to be installed on water service lines as a containment backflow prevention device assembly because the PVB is not designed for backpressure conditions, which could occur on service lines.