Which refrigerant does not require a room detector under ASHRAE Standard 15 if the ventilation system runs continuously?

R-717, or ammonia, is a refrigerant that is associated with specific safety protocols due to its toxicity and flammability. Under ASHRAE Standard 15, which governs the use of refrigerants in occupied spaces, certain conditions must be met to ensure safety and proper ventilation.

If the ventilation system operates continuously, it effectively dilutes any potential ammonia leaks in the air, minimizing the risk of dangerous concentrations. This is a crucial consideration since ammonia is hazardous in higher quantities. In contrast, the other refrigerants listed (R-134a, R-410A, and R-22) do not have the same level of toxicity but may still require specific safety measures, including detection systems, to ensure that any leaks are promptly identified and addressed to safeguard occupants.

The ability to forego the use of a room detector for R-717 under these specific ventilation conditions highlights the importance of context in safety regulations, recognizing that adequate ventilation can significantly mitigate risks associated with the use of certain refrigerants.