The purpose of this SAE Recommended Practice is to establish the specific criteria for the selection of a replacement refrigerant for mobile CFC-12 (R12) air conditioning systems. This document provides guidelines for qualifying candidate refrigerant. The requirements include laboratory and field testing. The alternate refrigerant shall provide comparable system performance as CFC-12 as defined herein. The vehicle testing shall be conducted on representative vehicle manufacturer's product line, in which the refrigerant is intended to be used, such as cycling clutch orifice tube, constant run orifice tube, cycling clutch expansion valve, or continuous run expansion valve refrigerant system. This document is complete only when combined with the requirements of SAE J1657.