Backflow Prevention Practice Exam

A barometric loop must be installed 35 ft (10.7 m) above the highest ____?

1. Boiler

2. Fixture outlet

3. Gate valve

4. Service connection

The correct answer is: Fixture outlet

A barometric loop is a type of backflow prevention device that uses the principle of gravity and elevation to protect potable water supplies from contamination. This device is specifically designed to be installed at a certain height to ensure that it maintains the required hydraulic conditions to prevent backflow. The correct height for installation of a barometric loop is determined by its position relative to potential sources of backflow. The highest fixture outlet, which refers to the most elevated point in a plumbing system where water is used, is critical because it establishes the potential for backflow to occur if the pressure within the system drops. By installing the barometric loop 35 feet above the highest fixture outlet, you create a physical barrier that ensures any backflow would have to overcome significant elevation, which is unlikely to happen in practice, thus protecting the water supply from contamination. The importance of this installation height is rooted in maintaining the safety and integrity of the water supply system. If the barometric loop were installed lower than this height, it would not effectively prevent contaminants from flowing back into the potable water supply, posing a potential health risk.