Backflow Prevention Practice Exam

A properly installed barometric loop will prevent _____?

1. Backpressure

2. Backsiphonage

3. Freezing

4. Surges

The correct answer is: Backsiphonage

A properly installed barometric loop is designed specifically to prevent backsiphonage, which is the reverse flow of water due to a negative pressure in the supply line. Backsiphonage can occur when there is a sudden drop in pressure in the water supply system, such as when there is a main break or high water demand in the area. The barometric loop functions by utilizing the principle of atmospheric pressure. It creates a vertical rise in the piping system that provides a physical barrier against the possibility of contaminated water flowing back into the potable water supply. If backsiphonage occurs, the water would have to travel vertically upward against gravity in the loop, which is not possible unless there is sufficient pressure to do so. Therefore, the barometric loop effectively protects the water supply by maintaining a separation between potable water and potential contaminants. In contrast, while backpressure, freezing, and surges are relevant concerns in plumbing systems, they are mitigated through different types of devices or methods. Each of these situations requires specific solutions, such as pressure relief valves for backpressure or thermal insulation for freezing, emphasizing the unique role that a barometric loop has in specifically preventing backsiphonage.