What is a pressure-type vacuum breaker (PVB) and where can it be used?
A pressure-type vacuum breaker (PVB) is a backflow prevention device designed to operate under continuous supply pressure, so a shut-off valve may be located downstream of the device. “Continuous” is defined as 12 hours or longer. A device not designed for continuous supply pressure may “freeze” in one position and become inoperative. Like the AVB, the PVB cannot be subject to back-pressure backflow conditions.
