Cross Connection Practice Exam

Which backflow preventer consists of two check valves and two shutoff valves?

1. Reduced Pressure Principle

2. Atmospheric Vacuum Breaker

3. Double Check Valve Assembly

4. Pressure Vacuum Breaker

The correct answer is: Double Check Valve Assembly

The Double Check Valve Assembly is designed specifically to prevent backflow in plumbing systems and consists of two check valves positioned in series. The primary function of this assembly is to ensure that any water that has the potential to flow backward into the potable water supply is effectively stopped. Each check valve operates independently, providing an additional layer of protection against backflow. The configuration of this assembly is crucial because it effectively isolates the drinking water supply from potentially contaminated sources. Accompanying the two check valves are two shutoff valves, one located on either side of the check valves. These shutoff valves allow for maintenance and testing of the check valves without needing to drain the entire system, ensuring continued safety and compliance with plumbing codes. In contrast to other backflow preventers like the Reduced Pressure Principle or Pressure Vacuum Breaker, which have different configurations and operational mechanisms focused on specific situations, the Double Check Valve Assembly's specific setup of two check valves and two shutoff valves makes it uniquely effective for many general-purpose applications where contamination risk is present but not imminent.