Which backflow device provides effective protection from both backpressure and backsiphonage?

Which backflow device provides effective protection from both backpressure and backsiphonage?

• A. Reduced Pressure Principle backflow device
• B. Double Check backflow device
• C. Air Gap
• D. Pressure Regulating Valve

Answer: (B)

Backflow occurs when water from a downstream system can flow back into the potable supply due to backpressure or backsiphonage. The device that provides protection against both of these conditions is the double check backflow preventer. It uses two check valves in series, with a testable chamber between them, so water can only flow forward into the system. If pressure tries to push water backward, both checks must fail for backflow to occur, which makes it effective against both backpressure and backsiphonage. This makes it suitable for many moderate-hazard cross-connections. A reduced pressure device offers even greater protection and is used for higher hazards, while an air gap provides a physical separation, and a pressure-regulating valve by itself does not prevent backflow.

Backflow occurs when water from a downstream system can flow back into the potable supply due to backpressure or backsiphonage. The device that provides protection against both of these conditions is the double check backflow preventer. It uses two check valves in series, with a testable chamber between them, so water can only flow forward into the system. If pressure tries to push water backward, both checks must fail for backflow to occur, which makes it effective against both backpressure and backsiphonage. This makes it suitable for many moderate-hazard cross-connections. A reduced pressure device offers even greater protection and is used for higher hazards, while an air gap provides a physical separation, and a pressure-regulating valve by itself does not prevent backflow.