According to the AHRI standard, what is the maximum acceptable level of unsaturated impurities in HFC-134a?

HFC-134a is a refrigerant commonly used in various cooling applications, and maintaining its purity is essential for efficient performance and system longevity. The AHRI (Air-Conditioning, Heating, and Refrigeration Institute) standard outlines specific guidelines to ensure the quality of refrigerants.

The maximum acceptable level of unsaturated impurities in HFC-134a is set at 40 PPM (parts per million). This standard is critical because unsaturated impurities can cause issues such as system degradation, increases in pressure drop, and potential reactions that could lead to the formation of harmful byproducts. By adhering to this purity standard, technicians can help ensure the reliability and efficiency of refrigeration systems using HFC-134a.

While other choices reflect varying levels of unsaturated impurities, they do not meet the established standards for HFC-134a. Therefore, the choice of 40 PPM is aligned with industry standards, ensuring the proper functioning and safety of systems using this refrigerant.