R-1234yf: Reaction and Response

By Jim Taylor Editor MACS ACtion Magazine

As noted last week, the announcement by Daimler A.G that it will continue to use R-134a and not R-1234yf in its new cars sent a substantial shock throughout the automotive industry. Here are the first public statements in response to that announcement.

  DuPont statement in response to press release issued by Daimler on Sept.    25, 2012

Based on extensive data, and on independent risk assessments, HFO-1234yf can be used   safely as an automotive refrigerant.DuPont was surprised to read the Sept. 25, 2012 press release issued by Daimler. According to the release, the test they conducted did not involve other industry members or undergo peer review.

DuPont has requested the details of Daimler’s data and testing methodology, and we will review them as soon as possible, to understand if they do indeed represent new findings.

The statements in Daimler’s release are not consistent with the findings of extensive industry evaluations, including a paper that was co-authored by Daimler and presented by the German automakers association (VDA) on Sept. 17, 2012 in Frankfurt, which stated, “R1234yf equipped vehicles are as safe as those using R134a – for occupants, mechanics, first emergency responders and fire fighters.”

DuPont co-developed HFO-1234yf in response to Europe’s Mobile Air Conditioning (MAC) Directive, which requires an automotive refrigerant with a global warming potential (GWP) under 150. HFO-1234yf refrigerant has a GWP of 4, which is 99.7% lower than the refrigerant used in most cars today.In addition, HFO-1234yf enables energy efficiency, and has an optimal balance of safety, performance, sustainability and cost.

HFO-1234yf has performed well in extensive safety and efficacy testing conducted by leading automotive manufacturers and by independent testing groups such as SAE International. The SAE conducted an international Cooperative Research Program in which leading automakers participated.

According to SAE, “thorough international testing, including independent, third-party, documented tests…using real-world conditions have demonstrated that HFO1234yf is safe to use in mobile air conditioning.” The SAE also concluded that “HFO1234yf is safe to use in automobiles designed for use with HFO1234yf as verified through extensive third-party testing.”


Flammability: Risk assessments have shown that there is no significant additional flammability risk for HFO-1234yf versus R-134a, which it was developed to replace. Multiple industry risk assessments have been conducted, involving extensive testing in real life conditions, simulating many sorts of leaks, using various ignition sources, and simulating front-end crash conditions. In these tests, the refrigerant was extremely difficult to ignite even with very high temperature sources and flames did not spread in any of the tests.

HF Formation:
Industry groups have also thoroughly evaluated the risk of hydrogen fluoride (HF) formation due to exposure of HFO-1234yf to extreme heat or a flame. They concluded that use of HFO-1234yf in automotive air conditioning systems poses no increased risk compared to the current refrigerant HFC-134a, which has been used for nearly 20 years. During more than six decades’ use of fluorine-based automotive refrigerants, there is no documented incident related to HF exposure from refrigerant decomposition in a vehicle fire.

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Statement from Honeywell Performance Materials and Technology

The Mercedes-Benz media announcement last week that they had conducted additional in-house testing of HFO-1234yf on their vehicle designs came as a surprise to the entire industry. After committing to meet with Honeywell on Monday, October 1, to discuss their testing protocols, Mercedes-Benz canceled the meeting and still has not shared these details with us. Honeywell hopes to understand their test protocols and assess any deviation from industry standards.

Our primary concern about the Mercedes-Benz testing is whether it is relevant to automobile safety and whether any new insights can be added to the rigorous and comprehensive studies conducted over a period of several years that concluded that HFO-1234yf is safe for automobile use. These evaluation tests were conducted within the Cooperative Research Program (CRP) led by SAE, the independent global association of automotive engineers, together with leading automakers including Daimler and several independent institutes worldwide.

The unilateral decision by Mercedes-Benz to work on its own without engaging the rest of the industry is not typical of the way the industry assesses the safety of new products. In addition, it is worth exploring whether the test results apply only specifically to one automaker’s vehicles and thus may be remedied through better design.

Honeywell takes product safety and environmental responsibility very seriously, and stands committed to the global adoption of HFO-1234yf. Compared with R134a, the current refrigerant used in cars, HFO-1234yf offers a 99.7 percent improvement in global warming potential.


About macsworldwide

Mobile Air Conditioning Society (MACS) Worldwide Founded in 1981, MACS is the leading non-profit trade association for the mobile air conditioning, heating and engine cooling system segment of the automotive aftermarket. Since 1991, MACS has assisted more than 600,000 technicians to comply with the 1990 U.S. EPA Clean Air Act requirements for certification in refrigerant recovery and recycling to protect the environment. The Mobile Air Conditioning Society (MACS) Worldwide’s mission is clear and focused--as the recognized global authority on mobile air conditioning and heat transfer industry issues. www.macsw.org
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