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SAE International analysis of R-1234yf nears completion

April 23, 2013: The SAE International Cooperative Research Project (CRP1234-4) team, formed last year to perform an updated engineering safety analysis of R-1234yf refrigerant, met during the SAE World Congress in Detroit. The team includes European, North American and Asian OEMs including Chrysler/Fiat, Ford, General Motors, Honda, Hyundai, Jaguar Land Rover, Mazda, PSA, Renault and Toyota.

The SAE CRP has carefully evaluated the extensive testing conducted by its members. The fault tree analysis was subsequently updated with regard to actual collision scenarios and is now complete pending final review. Based on this conservative analysis, the team believes that the R-1234yf refrigerant is safe and effective to use in automotive applications. The risk of passenger exposure to a vehicle fire associated with this refrigerant is exceptionally remote. This is consistent with the overall risk levels established by the original SAE CRP1234-3.

In September of 2012, Daimler announced that it had developed a new test method that demonstrated an additional risk of post-collision fires in vehicles using R-1234yf. In response, SAE CRP1234-4 was formed to further evaluate the safety of R-1234yf. All OEMs, including Daimler, were invited to participate. The SAE CRP team members have conducted numerous additional tests of various types to study ignition of an R-1234yf leak in a crash-damaged vehicle.

The SAE CRP team of OEMs has concluded that the refrigerant release testing conducted by Daimler is unrealistic and that it is not an appropriate test to verify the safety of refrigerant applications in vehicles. The Daimler testing did not include any actual vehicle collisions or the mitigating factors that occur in an actual collision. These factors include the quenching effect of front end compartment deformation, the extinguishing effect of steam released due to radiator breakage, and dispersion of the refrigerant from the condenser outside the engine compartment. Daimler’s refrigerant release apparatus and nozzle does not represent actual crash-damaged refrigerant lines, and was found to be artificial.

Fault tree analysis, as conducted by the SAE CRP, is the most appropriate approach for evaluating risks of new alternative refrigerants. This approach has been recommended and employed by numerous public and private organizations, including the U.S. Environmental Protection Agency, the U.S. Department of Energy, the International Electrotechnical Commission, the European Union Joint Research Centre and the United Kingdom Health and Safety Executive.

The SAE CRP is currently finalizing its report and is targeting June 2013 for publication.

SAE International is a global association of more than 138,000 engineers and related technical experts in the aerospace, automotive and commercial-vehicle industries. SAE International’s core competencies are life-long learning and voluntary consensus standards development. SAE International’s charitable arm is the SAE Foundation, which supports many programs, including A World In Motion® and the Collegiate Design Series™.

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