Backflow Prevention Practice Exam

Which of the following statements is true about pressure vacuum breakers?

1. They are installed below the discharge point

2. They can be submerged underwater

3. They require a minimum elevation above the high water line

4. They cannot be used in frost-prone areas

The correct answer is: They require a minimum elevation above the high water line

Pressure vacuum breakers are designed to prevent backflow in irrigation systems and require specific installation parameters to function correctly. One key factor is that they need to be installed at a minimum elevation above the high water line. This positioning allows them to effectively break the vacuum that could occur in the system, thus preventing contaminated water from siphoning back into the potable water supply. If they were installed below the high water line, there would be a risk of backflow occurring in situations where negative pressure could develop in the system. The requirement for elevation ensures that the device operates properly during normal functioning and in scenarios where backpressure might occur. This is critical for maintaining the integrity of the drinking water system and ensuring public health safety. In contrast, the other statements do not align with standard practices and requirements for pressure vacuum breakers. They are not designed to be submerged underwater, as this could inhibit their function. Additionally, although they can be used in frost-prone areas, it is generally advised to take precautions against freezing conditions to ensure reliable operation.