What is required for Al refrigerants as per ASHRAE Standard 15?

The requirement for aluminum refrigerants under ASHRAE Standard 15 involves the necessity of a sensor and alarm for oxygen deprivation. This is critical because certain refrigerants can displace oxygen in the air, which poses a safety hazard for individuals working in areas where these refrigerants are used. The inclusion of a sensor and alarm system ensures that if oxygen levels drop dangerously low, a warning is provided to occupants, allowing for timely evacuation or corrective actions to be taken. This aligns with ASHRAE's focus on ensuring safety in environments where refrigerants are utilized, particularly in terms of preventing asphyxiation risk and promoting health standards.

Other options may involve equipment or measures that are important for the functionality and monitoring of refrigeration systems, but they do not directly address the specific safety measure needed to protect against oxygen depletion. A pressure gauge, for example, is more related to monitoring the operational status of the refrigeration system rather than directly safeguarding against the risks associated with low oxygen levels. Therefore, the focus on oxygen deprivation underscores the importance of health and safety regulations in refrigeration applications.