Which device is used to prevent backflow on a service connection?

Which device is used to prevent backflow on a service connection?

• A. A backflow prevention device on service connection: Air gap
• B. A reduced pressure principle backflow assembly (RP)
• C. A check valve
• D. A surge suppressor

Answer: (B)

On a service connection, preventing backflow requires a device that provides reliable isolation against both backsiphonage and backpressure. A reduced pressure principle backflow assembly achieves this by using two check valves with a relief valve between them that vents to the atmosphere. If downstream pressure drops or contamination tries to flow back toward the supply, the relief valve opens and prevents reverse flow, giving the highest level of protection for the distribution system on a service line. An air gap is another backflow protection method but is typically used at fixtures or points of use rather than the service connection itself. A simple check valve alone can be bypassed or fail under certain conditions, and a surge suppressor does not prevent backflow. Therefore, the reduced pressure principle backflow assembly is the most appropriate device for service-connection protection.

On a service connection, preventing backflow requires a device that provides reliable isolation against both backsiphonage and backpressure. A reduced pressure principle backflow assembly achieves this by using two check valves with a relief valve between them that vents to the atmosphere. If downstream pressure drops or contamination tries to flow back toward the supply, the relief valve opens and prevents reverse flow, giving the highest level of protection for the distribution system on a service line. An air gap is another backflow protection method but is typically used at fixtures or points of use rather than the service connection itself. A simple check valve alone can be bypassed or fail under certain conditions, and a surge suppressor does not prevent backflow. Therefore, the reduced pressure principle backflow assembly is the most appropriate device for service-connection protection.