Mercedes-Benz Rejects Environmentally Friendly Air Conditioner Refrigerant Because of Fire Danger

By Blake Z. Rong | September 26, 2012
What's in your air conditioning? Who cares, usually is the answer, unless your car was built during the Watergate scandal and blows with the asthmatic force of a toddler with a Silly Straw. The refrigerant in your car is slowly being switched over to a more environmentally friendly version, which sounds great on paper—except for one minor caveat, with which Mercedes-Benz is taking issue. Current automotive air conditioning units use R134a, which has been the standard for years. But it's being phased out: some states like Washington and the ever-fastidious California restrict the use of it in recharging systems. The new refrigerant is called R1234yf, and carries a lower global warming potential than R134a, expressed in a number in accordance with the way humans process data: about 335 times less damaging to the thin remaining wisps of exosphere that we laughably call an ozone "layer." It is a direct replacement in a new car, doesn't require specialized equipment to install, and—with the forcible greening of European Union policy—will be a requirement on European cars starting right around last year. To heck with that, says Mercedes-Benz. Because as it turns out, the new eco-friendly R1234yf is "slightly flammable," according to the Society of Automotive Engineers, which doesn't sound very eco-friendly at all.
So Mercedes-Benz is wisely eschewing it—but not without testing it themselves: its engineers conducted a test simulating a head-on collision, where the lines to the air conditioning refrigerant were severed and R1234yf sprayed all over the hot engine bay. And it turns out, "the refrigerant which is otherwise difficult to ignite under laboratory conditions can indeed prove to be flammable in a hot engine compartment." Meanwhile in the States, GM is introducing the new refrigerant to all of its new cars: in all 2013 Buick, Chevrolet, GMC and Cadillac models, with the XTS the first to receive it. We can see the headlines now: GM RISKING AMERICAN LIVES! ARE CHEVROLETS FLAMMABLE? But then again, American cars have always maintained a reputation of forming icicles on the air vents. The flammability can only be damped by the icebox-quality cool, enough to change ecosystems just by rolling up the windows. But the new refrigerant is more expensive to produce, and because of that niggling flammability aspect it requires specialized equipment, a cost passed down to your local repair shop. We've come a long way since CFCs; is this new greenhouse gas eliminating refrigerant as much of a boon? Or are the flammability concerns present but exaggerated, as the SAE found out? Source: Mercedes-Benz