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SAE International Announces Progress Update on Alternate Refrigerant Testing by MRB CRP

WARRENDALE, Pa., May 13, 2013 -  The SAE International MAC Refrigerant Blend Cooperative Research Program [MRB CRP], comprising a group of leading global OEMs plus Tier One suppliers, has been assessing the operating, technical and safety performance of two low GWP blended refrigerants developed by Mexichem. These blended refrigerants meet the requirements of the EU MAC Directive. As the world’s vehicle MAC usage increases there will be a need for additional refrigerant supply in meeting the international environmental goals. 

The blends are based on R-1234ze(E) with additional refrigerants that are all currently in production.  AC5 is a mixture of R-32, R-152a and R-1234ze(E) and AC6 is a mixture of R-744, R-134a and R-1234ze(E).Details of these refrigerants and promising initial findings were shared in October 2012 at the SAE International Thermal Management System Symposium [TMSS] event in Phoenix, AZ.

Since then more in-depth work has continued and at a meeting of the MRB CRP held 14th and 15th April 2013 in Detroit, the team reviewed the progress of this work and decided there was a need to share information relevant to the public discussion about low GWP refrigerants for MAC applications.

Specifically the MRB CRP wants to ensure that information that it has generated regarding the performance, flammability and risk assessment of these low GWP blended refrigerants is available to be included in the important discussion regarding replacement of MAC system refrigerant.  Based on a detailed fault tree analysis AC6 offers a risk profile that is equal to or better than that of R-1234yf in all significant respects.  AC5 is comparable to R-1234yf

MRB CRP members delivered, at TMSS 2012, several presentations on different technical aspects of AC5 and AC6 including performance, risk assessment and materials compatibility showing that AC5 and AC6 were technically credible low GWP refrigerants. [These presentations are available on the SAE International website:].  Since late 2012 MRB CRP has been focusing on the low GWP blended refrigerant AC6 and has already reported on its reduced flammability compared to R-1234yf at TMSS 2012.

In order to ensure that information generated by the work of MRB CRP is available the CRP has now decided to issue a preliminary report reflecting these presentations as well as updated information and expects to issue further reports as the project progresses before MRB CRP members present final reports on the risk assessment, first fill, servicing and flammability work at the 2013 TMSS in October, 2013 in Troy, Michigan.



Inquiries about the MRB CRP, its membership, the scope of the work being carried out and the fluids under assessment should be directed to Enrique Peral (Chair)( and William Hill (Technical Advisor)(


MRB CRP is a Cooperative Research Program administered by SAE and comprising the following companies: Behr, Bosch, Chrysler, Cinetic Filling, Daimler, Denso, Doowan, General Motors Company, Halla Visteon Climate Control, Hyundai, Jaguar Land Rover, Mexichem, Nissan, PSA, Renault, SAIC Motors, Sanden, Schrader International, Texa and Volvo Cars.

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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