EU Debate Over New Refrigerant Escalates

Europe plans to phase out R134a, the auto industry's standard refrigerant for air-conditioning systems, beginning in January. But Daimler AG says its tests show that the only planned substitute HFO-1234yf can ignite in a crash and release highly toxic fumes.

Daimler's test in August and subsequent tests by other carmakers that duplicated the flammability problem has left regulators uncertain. The EU's current timetable would eliminate 134a by 2017. But Reuters reports that the German auto industry has asked for a six-month delay to allow more testing.

Honeywell and DuPont, which co-developed 1234yf and currently are the world's sole source of the refrigerant, complain that Daimler's tests were secret and not verified by an outside party. They also consider Daimler's concern suspiciously timed, coming on the eve of a standard announced six years ago and after years of independent successful tests by 18 other laboratories.

Plans by the two companies to open a large plant in China this year to make 1234yf have already been delayed for months by governmental licensing issues.

The EU ordered the phase-out of R-134a to help reduce global warming. Today's R-134a has a global warming potential (GWP) rating of 1,430. The EU law sets a GWP cap at 150. HFO-1234yf has a GWP of 4 and can be used in existing A/C architectures with few modifications to those systems.

Daimler's test simulated crash damage that released a fine spray of the refrigerant and air-conditioning system compressor oil. The mix immediately caught fire when it hit the hot surfaces of the 1.6-liter turbocharged test engine, releasing toxic hydrogen fluoride that turned the windshield glass opaque. HF forms highly corrosive hydrofluoric acid that can quickly cause blindness or severe burns on contact with human flesh.

The question for carmakers and regulators is whether Daimler's test conditions could occur in an actual crash. Reuters says follow-up tests by 13 major carmakers duplicated Daimler's results in more than two-thirds of the simulations.

Honeywell acknowledges that 1234yf shows "mild flammability." But the company declares the new refrigerant is "safe under the most extreme conditions" and less risky than many other flammable materials found under the hood of a car.

Honeywell's own tests spraying liquid mixed with 5% oil onto a metal plate heated to about 600 C found that motor oil, automatic transmission fluid, radiator antifreeze, brake fluid, diesel fuel and compressor lubricant all burned. But the company says neither 134a nor 1234yf ignited.