The U.S. Environmental Protection Agency (EPA) has made a final rule approving the use of R-152a refrigerant in automobiles as an alternative to the industry's R-134a, according to an Automotive Aftermarket Industry Association (AAIA) report. R-152a has a much lower Global Warming Potential (GWP) than the current refrigerant in use. R-152a's GWP is 130. In comparison, R-134a has a GWP of 1,300. However, R-152a is also mildly flammable. For this reason, the EPA's rule requires that new R-152a systems be designed to avoid occupant exposure to concentrations of the refrigerant above 3.7 percent in the passenger cabin for more than 15 seconds even in the event of a leak. Further, the agency is requiring the air conditioning systems to be prominently labeled "CAUTION SYSTEM CONTAINS FLAMMABLE R-152a REFRIGERANT – TO BE SERVICED ONLY BY QUALIFIED PERSONNEL." The label must be mounted in the engine compartment on a component that is not normally replaced and where it can be easily seen, states the AAIA report. The label also will include refrigerant identification information and indicate that the refrigerant is flammable. Additionally, the final rule recommends further training for vehicle service technicians and that the car companies conduct and keep on file R-152a systems failure mode and effects analysis (FMEA) tests they perform to ensure that the air conditioning system are safe and are designed with sufficient risk mitigation devices to ensure that occupants are not exposed beyond recommended levels. According to EPA, this rulemaking applies to the vehicle manufacturers, but does not impact service technicians. A separate rulemaking will be issued to specify new equipment and practices required in the servicing of air conditioning systems using R-152a.
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