Which two items must NH3 machine rooms have that are compliant with plumbing code?

For NH3 (anhydrous ammonia) machine rooms, compliance with plumbing code necessitates specific features to ensure safety and proper functionality. The inclusion of a floor drain is crucial because it allows for the safe disposal of any potential leaks or spills of ammonia, which can be hazardous. A backflow preventer is equally important; it prevents contamination of potable water systems by ensuring that ammonia cannot flow back into the public water supply in the event of pressure changes or equipment failures.

While other features might enhance safety and operational efficiency within the machine room—such as ventilation to manage air quality, temperature control to maintain optimal system performance, or safety exits and signage—these are not specifically mandated by plumbing code. Instead, the focus of plumbing code compliance is on preventing contamination and managing spills effectively, making the floor drain and backflow preventer vital components for NH3 machine rooms.