Daimler Prefers CO2 AC Gas
Daimler Benz Says 1234yf Safety Report Too Narrow
As our readers would be aware the Honeywell-DuPont refrigerant HFO-1234yf was the most preferred option by most of the world’s OEM’s to replace R134a. However, as previously reported Mercedes-Benz/Daimler were not convinced that it could be used safely due to flammability and toxicity when tested.
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The final report by the European Commission’s Joint Research Centre (JRC) that aimed to provide an analysis of the report by Germany’s Federal Motor Transport Authority (KBA) related to safety aspects of R1234yf (in vehicle A/C), concludes that under “normal and reasonably foreseeable conditions of use” there is no evidence of a serious risk associated with the refrigerant.
Mercedes-Benz (Daimler) however, has criticised the report for being too narrow, as it does not take into account the tests conducted by automakers or the evidence of potential hazards related to HF formation provided by other institutions. “Our preferred solution therefore continues to be the development of CO2 mobile air-conditioning systems,” said Daimler in reaction to the JRC report.
Our readers would recall that previous tests revealed toxic substances could be released in the event of a serious fire.
Both KBA and JRC shared the view that the level 1 and 2 tests, considered for the purpose of regulatory product safety purposes, do not provide evidence of a serious risk related to R1234yf. Under these two levels of the refrigerant release test, no refrigerant ignition and no HF release was recorded. However, under level 3 that included further leakage modifications and configurations in the refrigerant release setup:
• Two cars in 3 out of 6 tests released elevated HF concentrations under the hood (18, 133, 150 ppm)
• R1234yf ignited in one car in 2 out of 3 identical tests, and a high HF concentration was measured in the engine compartment (3300, 5400 ppm)
While the KBA pointed out that based on level 3 tests R1234yf would “not be without danger” and further testing is necessary to fully understand the flammability and HF formation related to the refrigerants, the JRC report concludes that to make deductions from level 3 is not appropriate in light of product liability legislation.
Similar Level 3 tests with R134a resulted in no ignition or elevated HF concentration.
Watch this space. More info, www.r744.com
