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Four Common Types of Backflow Prevention Devices for Irrigation Systems

Double Check Valve Assembly (DCVA)

  • This is the most widely used backflow prevention device on sprinkler systems. It can be installed below grade in a standard rectangular valve box. The irrigation system can be turned off at 1 of 2 shut off valves on the assembly.

Pressure Vacuum Breaker (PVB)

  • This device is approved for irrigation systems; however, it is rarely used because of its limitations. It must be installed above grade, 12 inches above the highest downstream sprinkler head and is subject to freezing in winter months. This device is also approved for chemical injection systems on sprinklers. The irrigation system can be turned off at 1 of 2 shut off valves on the assembly.

Reduced Pressure Zone Assembly (RPZA)

  • This device is approved for irrigation systems; however, it is rarely used because of its limitations. It must be installed a minimum of 12 inches above grade, and is subject to freezing in winter months. This device is also approved for chemical injection systems on sprinklers and systems that might create backpressure. The irrigation system can be turned off at 1 of 2 shut off valves on the assembly.

Atmospheric Vacuum Breaker (AVB)

  • This device is commonly found on older sprinkler systems, but is not approved for new installations because it is non-testable and cannot have any downstream valves. It must be replaced by a Double Check Valve Assembly when upgrading an irrigation system. There are no shut off valves to isolate the irrigation system.