A lawn irrigation system with chemical injection is connected to a potable supply. This is classified as a high health hazard under backpressure and backsiphonage conditions. Which backflow assembly is required?

Explanation

Chemical injection creates a high health hazard and can occur under backpressure, so a reduced-pressure principle assembly is required because it protects against both backpressure and backsiphonage of a health hazard. An atmospheric vacuum breaker only protects against backsiphonage and cannot be under continuous pressure. Dual checks are for low-hazard applications only.