A backflow preventer is a means or mechanism to prevent backflow. The basic means of preventing backflow is an air gap, which either eliminates a cross-connection or provides a barrier to backflow. The mechanism for preventing backflow is a mechanical backflow preventer, which provides a physical barrier to backflow.
Type of Backflow Preventers
The principal types of mechanical backflow preventers are:
- Double check valve assembly
- Pressure vacuum breaker assembly
- Reduced-pressure principle assembly