Final answer:
ASHRAE Standard 15 commonly requires refrigerant monitors for refrigerants like R-123 due to potential health risks. While the standard can vary based on the refrigerant's toxicity, refrigerant monitoring is generally mandated for any that can significantly affect health, particularly in the event of a leak.
Step-by-step explanation:
Under ASHRAE Standard 15, which is related to safety standards for refrigeration systems, equipment room refrigerant monitors are typically required for refrigerants that have higher toxicity levels or pose greater risks to human safety. Among the options provided, ASHRAE Standard 15 specifically would call for refrigerant monitoring in the machinery room for refrigerants like R-123, which is a chlorofluorocarbon (CFC). This is due to its potential to cause harm if it leaks, as it can displace oxygen, leading to asphyxiation, and may have other health impacts. It's also worth noting that regulations and codes can evolve, so it's essential to refer to the latest version of the standard for accurate requirements.
The amount of refrigerant that necessitates a refrigerant detector depends on the specific refrigerant and the size of the equipment room among other factors. Systems using R-11, R-123, and other refrigerants that can have significant health effects in the event of a leak are those where monitoring is more commonly required.
However, it is important to review the ASHRAE Standard 15 for the most up-to-date information, as the standards can change. For refrigerants such as R-134a, which are less harmful, monitoring requirements may differ based on the charge size and application context.