What is the minimum reading required when performing a directional flow test on the #2 check valve of a RPZ?

When performing a directional flow test on the #2 check valve of a Reduced Pressure Zone (RPZ) assembly, the minimum reading required is 1.0 psid. This value is established based on the operational standards for RPZs, which are designed to ensure that the check valves maintain adequate pressure differences to function effectively.

The rationale behind the minimum reading of 1.0 psid is tied to the need to demonstrate that the check valve is working properly by preventing backflow. A pressure differential of at least 1.0 psid is necessary for the valve to close fully against any potential backflow. If the reading were lower than 1.0 psid, it could indicate that the valve is not properly sealing, which would compromise the safety and integrity of the water supply system.

Understanding this minimum threshold is crucial for professionals in the field, as it allows them to verify the functionality of the RPZ assembly and ensure compliance with regulatory standards, thereby protecting public health and safety.