Backflow Prevention Practice Exam

Backsiphonage may occur when the pressure inside copper tubing is ____?

1. Greater than atmospheric pressure

2. Greater than barometric pressure

3. Less than absolute pressure

4. Less than atmospheric pressure

The correct answer is: Less than atmospheric pressure

Backsiphonage occurs when there is a negative pressure in a plumbing system, which can cause contaminants to be siphoned back into the potable water supply. The situation typically arises when the pressure inside a system drops below atmospheric pressure. When this negative pressure condition exists, it can lead to the drawing of water from the surrounding environment, including potentially contaminated sources, into the clean supply. In this context, since atmospheric pressure is the threshold that prevents backsiphonage, the correct answer indicates that when the pressure inside copper tubing is less than atmospheric pressure, backsiphonage can occur. This is critical in maintaining the integrity of the water supply and preventing contamination, highlighting the importance of proper backflow prevention measures.