This SAE Recommended Practice is restricted to mechanical vapor compression refrigerant systems that provide cooling for the occupant's compartment. This document provides guidelines for refrigerant containment and safety for a mobile air-conditioning (A/C) system. It is not intended to restrict the use of, or further development of, other types of refrigeration systems for passenger compartment cooling. Should other systems be found practical at some future time, this document may be amended or an additional recommended safety practice drawn up for other types of systems. This document only addresses CFC-12 (R-12) and HFC-134a (R-134a) refrigerants. To prevent mobile A/C system refrigerant contamination, all other alternate refrigerants considered for automotive use require unique service fittings.