A fire sprinkler system with no antifreeze or chemical additives is connected to the potable water supply under continuous pressure. Which assembly is the appropriate minimum protection for this low hazard connection?

Giải thích

A non-additive sprinkler system is a low hazard (pollutant, not contaminant) connection under continuous pressure, which is the exact application for a double check valve assembly. A reduced pressure assembly exceeds the minimum required here and adds an unnecessary relief discharge. An atmospheric vacuum breaker may never be used under continuous pressure, and a pressure vacuum breaker protects against back-siphonage only, not back-pressure.