What type of backflow prevention is used between the sprinkler and circuit valve?

• A. Pressure vacuum breaker
• B. Reduced pressure principle preventer
• C. Atmospheric vacuum breaker
• D. Double check valve

Answer: (C)

Backflow prevention in irrigation protects drinking water by stopping irrigation water from flowing backward into the potable supply. An atmospheric vacuum breaker is a simple device placed on the zone line between the circuit valve and the sprinkler heads. When pressure in the line drops, the vent opens to the atmosphere, letting air into the line and breaking any siphon, so contaminated water can’t be drawn back toward the supply. It’s a common, inexpensive choice for low-hazard residential irrigation because it provides effective back-siphonage protection without the complexity of more robust devices. Remember it only guards against back-siphonage, not backpressure, and must be installed with the vent end elevated above the highest head and in a location suitable for annual maintenance and winterization.