In the International Fire Code, Section 606 – Mechanical Refrigeration has two distinct requirements regarding the refrigerant detector(s) and their alarm signal and in both requirements, the phrase “approved location” is used. In one case, they are talking about the location of the actual refrigerant detector/sensor, and in the other case, they are talking about where the detection alarm will be sounded. In the case of ammonia refrigeration systems, the engine/machinery room is often UNOCCUPIED, and therefore these detection systems play a KEY role in identifying leaks very early. But this relies on the detectors being placed in the proper area(s) AND the alarm(s) sounding in a way that it can be received and responded to. Section 606.8 Refrigerant Detector states: