Which ASHRAE refrigerant safety classification denotes the most toxic refrigerant?

The correct classification for the most toxic refrigerants is Class B3. In the ASHRAE refrigerant safety classification system, refrigerants are categorized based on toxicity and flammability. Class B refers to higher toxicity levels compared to Class A, where Class B1, B2, and B3 indicate increasing levels of toxicity.

Class B3 encompasses refrigerants that present severe toxicity risks in both short-term and long-term exposures. This classification implies that handling and exposure to refrigerants within this class require strict safety measures and protocols due to their potential health hazards. Understanding these classifications is essential for ensuring the safety of personnel working with refrigerants and to comply with regulatory standards.

In contrast, Class A refrigerants are considered to have low toxicity, and as the subclasses of B1 and B2 indicate, while they are more toxic than Class A, they still do not reach the high toxicity levels characteristic of Class B3. Thus, recognizing the significance of Class B3 helps professionals prioritize safety when working with these substances.