A system that includes a chemical injector must have what type of protection for the potable system?

A system that includes a chemical injector requires a reduced pressure zone (RPZ) backflow prevention assembly to protect the potable water supply. This type of protection is essential because a chemical injector introduces substances that could potentially contaminate the drinking water. The RPZ is designed to maintain a lower pressure in the supply line than in the protected system, which ensures that if a backflow event occurs, the potentially contaminated water cannot flow back into the potable water system.

The RPZ consists of two check valves with a pressure differential relief valve located between them. This setup effectively prevents backflow even under varying pressure conditions, maintaining the integrity of the potable water. By utilizing an RPZ, the system is compliant with regulations that safeguard public health, particularly in scenarios where hazardous substances are injected into the water supply.

Other options such as air gap separation, atmospheric vacuum breakers, or testable double check valves may serve certain protective functions but do not specifically provide the comprehensive protection needed where chemicals are being injected. For instance, while an air gap is an effective method of backflow prevention, it may not be practical in all situations requiring chemical injection. Similarly, an atmospheric vacuum breaker protects against backpressure but is not sufficient for systems with heightened contamination risks like those involving chemical inject