Cross Connection Practice Exam

Which backflow preventer is effective only under backsiphonage conditions?

1. Reduced Pressure Principle Assembly

2. Spill Resistant Type Pressure Vacuum Breaker

3. Atmospheric Vacuum Breaker

4. Double Check Valve Assembly

The correct answer is: Spill Resistant Type Pressure Vacuum Breaker

The Spill Resistant Type Pressure Vacuum Breaker is specifically designed to provide protection against backsiphonage conditions. When a negative pressure occurs in the distribution system, this type of backflow preventer effectively prevents contaminants from being drawn into the potable water supply. This backflow preventer has unique features that counteract the effects of backsiphonage, such as a special design that includes an air inlet, which allows air to enter the system and break the siphon effect. This activation occurs only when there's a drop in pressure, making the device effective specifically for those conditions. While other options might provide various types of backflow prevention, they do not solely function under backsiphonage circumstances. For instance, the Reduced Pressure Principle Assembly and the Double Check Valve Assembly are designed to address both backpressure and backsiphonage scenarios, making them broader in application. The Atmospheric Vacuum Breaker, while effective in certain situations, doesn’t have the same spill-resistant qualities as the Spill Resistant Type. This is why the Spill Resistant Type Pressure Vacuum Breaker is the best choice for effectiveness solely under backsiphonage conditions.