Which of the following refrigerants has a safety classification of B-1?

The refrigerant classified as B-1 indicates that it is non-toxic and has a low flammability classification, making it a safer choice in certain applications. HCFC-123 (R-123) fits this classification due to its properties. It is a hydrochlorofluorocarbon with a relatively low toxicity level and is not flammable under normal conditions, which contributes to its safety designation.

In contrast, the other refrigerants listed have different safety classifications based on their chemical properties. CFC-12 (R-12) and CFC-11 (R-11) are both classified as A1, indicating that they are non-flammable and have low toxicity, but they do not meet the criteria that would allow them to receive a B-1 classification. HFC-134a (R-134a) is generally considered to have a safety classification of A1 as well, meaning it is also non-flammable but does not possess the specific characteristics that define a B-1 classification. The classification system plays a crucial role in determining how each refrigerant should be handled, stored, and utilized in HVAC applications, giving preference to substances that pose a reduced risk to safety.