What is the role of air gaps in backflow prevention?

The role of air gaps in backflow prevention is essential for maintaining the safety of the potable water supply. An air gap acts as a physical barrier between the contaminant source and the clean water supply. When there is a physical separation, it prevents the potential for back pressure from contaminated water flowing back into the clean water system.

This design is critical because it ensures that even if a negative pressure situation occurs, where the flow of water reverses, contaminants cannot enter the potable system through the air gap. The air gap must be of a certain height, typically a minimum of two inches, to be considered effective in preventing any siphoning of water back into the clean supply. Overall, this method is one of the simplest and most effective means of backflow prevention, as it does not rely on mechanical parts that can fail over time.