Types of Backflow Preventers:

Air Gap (AG): A physical separation sufficient to Atmospheric Vacuum Breaker (AVB): A device prevent backflow between the free- flowing discharge that prevents back-siphonage by creating an end of the potable water system and any other atmospheric vent when there is either a negative system. Physically defined as a vertical distance equal pressure or sub-atmospheric pressure in a water to twice the diameter of the supply side pipe system. diameter, however, no less than one inch.

Double Check Valve Assembly (DCVA): An Pressure Vacuum Breaker (PVB): A device assembly of two independently operating check containing one or two independently operated check valves with tightly closing shut-off valves on each valves and an independently operated spring loaded side of the check valves, plus properly located test air inlet valve located on the discharge side of the cocks for testing each check valve. check valve(s). The device includes tightly closing shut-off valves on each side of the check valve(s) and properly located test cocks for the testing of the check valve(s).

Backflow Preventer with Intermediate Hose Bibb Vacuum Breaker: A device connected Atmospheric Vent (BPIAV): A device having two to a hose bib acting as an Atmospheric Vacuum independently operating check valves separated by Breaker; this device is not to be used under constant an atmospheric vent chamber. pressure.

Residential Dual Check: An assembly of two Reduced Pressure Backflow Preventer loaded, independently operating check valves (RPBP): An assembly consisting of two without tightly closing shut-off valves and test cocks. independently operating check valves with an Generally employed immediately downstream of the automatically operating differential relief valve water meter to act as a containment device. located between the two check valves, tightly closing shut-off valves on each side of the check valves, plus properly located test cocks for the testing of the check.

Barometric Loop: A fabricated piping arrangement rising at least thirty-five (35) feet at its topmost point above the highest fixture it supplies. It is utilized in water supply systems to protect against back- siphonage.