In its brief update, SAE noted that “To date, the majority of the OEMs involved in the new CRP do not believe that any of the new information reviewed will lead to a change in the overall risk assessment. With the exception of Daimler, no OEM in the CRP has provided information that would suggest a concern for the safe use of R-1234yf in their vehicles.”

Based on today’s announcement, Honeywell continues to believe that SAE International’s latest evaluation will only reconfirm the overwhelming body of data—including rigorous and comprehensive studies conducted in Europe, the US and Japan—that have clearly and repeatedly determined that HFO-1234yf is safe for use in automobiles. HFO-1234yf is a safe and effective refrigerant, and it is better for the environment.

—Dr. Ian Shankland, chief technology officer for Honeywell Performance Materials and Technologies

Previously, HFO-1234yf was the subject of comprehensive testing conducted over a three-year period under an SAE International CRP using proven, standard methods for evaluating new products and materials in automobiles. That CRP, which was sponsored by 15 global automakers, including all leading German automakers, concluded that HFO-1234yf is safe for use in automobile applications.

HFO-1234yf is an efficient, low-global-warming refrigerant that was developed as a direct replacement to HFC-134a in mobile air-conditioning (MAC) applications. Compared with HFC-134a, HFO-1234yf offers a 99.7% improvement in global warming potential and far exceeds the European Union Mobile Air Conditioning (MAC) Directive requirement.

Under certain conditions, HFO-1234yf exhibits mild flammability, at levels significantly lower than highly flammable materials already present under the hood of an automobile, including motor oil, automotive transmission fluid, radiator antifreeze, brake fluid, and compressor lubricant—not to mention fuel, Honeywell argued.

SAE International’s previous research projects have addressed the issue of flammability, employing fault-tree risk assessment techniques to evaluate the real-world possibility of a fire and human impact. SAE International said in its latest statement that it has expanded its fault-tree assessment in the new CRP to “ensure that newly-identified information and testing from each of the OEMs is incorporated.”

As part of SAE International’s programs, internationally recognized laboratories—including Hughes Associates Inc. and France’s Institute National de l’Environment Industriel et des Risques (INERIS)—conducted extensive testing on flammability and safety, and all concluded that HFO-1234yf is safe for use in automobiles, Honeywell said.