Backflow Prevention Practice Exam

An air-gap separation will tend to _____?

1. Admit air into the system to break a siphon

2. Allow air to backpressure instead of liquid

3. Dissipate chlorine residual

4. Generate a whistle to warn of a siphon

The correct answer is: Admit air into the system to break a siphon

An air-gap separation functions by creating a vertical space between the outlet of a water supply and the flood level of the receiving vessel. This gap ensures that there is no physical connection between the two, which is essential for preventing backflow. By allowing air into the system, the air gap effectively prevents the formation of a siphon when there's a drop in pressure or a potential reversal of flow. This mechanism is crucial in safeguarding potable water supplies from contamination. While the option regarding allowing air to backpressure instead of liquid points to the role of air in system dynamics, it does not accurately reflect the defining mechanism of an air gap, which specifically prevents siphoning by maintaining a separation. Similarly, dissipating chlorine residual is associated with chemical interactions in water treatment, and generating a whistle is not a standard function of an air gap. The primary purpose remains the prevention of any backflow that could compromise water quality, effectively accomplished through the air gap's design.