Which refrigerant does not require a refrigerant detector in the equipment room if mechanical ventilation is running continuously?

R-717, commonly known as ammonia, does not require a refrigerant detector in the equipment room if mechanical ventilation is continuously running. The use of mechanical ventilation helps to disperse any potential leaks of ammonia gas, reducing the risk of accumulating harmful concentrations in the enclosed space.

Ammonia is classified as a hazardous substance due to its toxicity at certain concentrations, but its physical properties allow for effective dilution when adequate ventilation is present. The continuous operation of mechanical ventilation ensures that any ammonia released into the air is quickly mixed with fresh air, preventing it from reaching dangerous levels that might warrant the use of a refrigerant detector.

In contrast, other refrigerants such as R-12, R-134a, and R-410A do not have the same toxic properties as ammonia but may still require monitoring systems due to their potential environmental impact or flammability in certain scenarios. Therefore, the presence of a refrigerant detector is often recommended for those refrigerants, especially in cases where leaks could result in significant environmental harm or safety concerns.