Describing refrigerant release testing undertaken by Daimler as "unrealistic", the SAE International Cooperative Research Project team has issued a statement confirming that R-1234yf refrigerant is safe for use in motor vehicle air conditioning systems.
In fact, the SAE team believes the risk of passenger exposure to a vehicle fire associated with this refrigerant is "exceptionally remote."
SAE members include 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.
As a result, 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.
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," the statement said.
"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."
The SAE CRP is currently finalizing its report and is targeting June 2013 for publication.
Only last month Volkswagen, Daimler, Audi, BMW and Porsche announced plans to develop CO2 technology as a more climate-friendly refrigerant for air conditioning systems.
The automakers are rejecting R-1234yf as a replacement for R134a.
Late last year Daimler undertook tests with R-1234yf which raised safety concerns.
In some head-on collision test scenarios, the refrigerant burst into flames, Daimler said.
