Cross Connection Practice Exam

Which method provides the highest degree of backflow protection?

1. Reduced Pressure Principle Assembly

2. Approved Air Gap

3. Pressure Vacuum Breaker

4. Double Check Valve Assembly

The correct answer is: Approved Air Gap

The approved air gap provides the highest degree of backflow protection because it creates a physical separation between the potable water supply and any potential contaminants. An air gap ensures that no backflow can occur, as it relies on the principle of gravity and the physical distance that must be maintained between the highest point of the water supply and the flood level of the discharge point. This method is particularly effective in preventing back siphonage, where negative pressure can pull contaminants back into the clean water supply. Unlike mechanical devices, which can fail or require maintenance, an air gap is a simpler, reliable solution that inherently prevents any interchange between potable water and non-potable sources. While other methods, like the reduced pressure principle assembly, provide substantial protection as well, they rely on mechanical parts that may be subject to failure or require testing and maintenance, making the air gap a more fail-safe option in critical applications.