Mercedes nixes new eco-friendly a/c refrigerant on fire safety claims

R1234yf

2,2,2,3 tetrafluoropropane, otherwise known as the refrigerant F1234yf, which Mercedes-
Benz calls too flammable for automotive use.

Daimler, the manufacturer of Mercedes-Benz cars, is putting the brakes on the new vehicle air conditioning refrigerant R1234yf. That new gas for a/c is being adopted by carmakers worldwide, and is intended to have a lower “global warming” impact compared to the currently used R134. Tests by Mercedes-Benz suggests that in real world-type crashes, R1234yf has a potential flammability that could cause a very localized warming. Specifically, R1234yf caused test cars to go up in flames.

The “climate-friendly chemical” R1234yfhad been poised to replace R134,  and had previously been consided safe, based on numerous laboratory and crash tests by international vehicle manufacturers and independent institutions.

However, in a statement released today, Daimler reported that in its new real-life test scenario, the refrigerant is dynamically dispersed at high pressure near to hot components of the test vehicle’s exhaust system. This corresponds to a serious head-on collision in which the refrigerant line is severed and the reproducible results demonstrate that refrigerant which is otherwise difficult to ignite under laboratory conditions can indeed prove to be flammable in a hot engine compartment. Similar tests of the current R134a refrigerant did not result in ignition.”

The new R1234yf refrigerant is slated for use by most automakers around the world. It requires few changes in equipment, either in the shop or vehicle, and it has similar performance characteristics to R132. With the U.S. and EU governments requiring the use of refrigerants with a “Global Warming Potential” of less than 150, and R134 having a 100 year GWP of 1300, a change was deemed necessary.

GWP attempts to measure heat trapped in the atmosphere by a “greenhouse gas” by comparing it to carbon dioxide. GWP is expressed in multiples of that of carbon dioxide. Based on the assumptions about global warming—or climate change, as it is otherwise called—the GWP of R1234yf is just 4.

Daimler is in effect placing the  immediate safety of passengers of Mercedes-Benz vehicles ahead of the purported long-term global warming effect of R134 refrigerant. The refrigerant E1234yf will not be used in Mercedes-Benz vehicles.

According to the statement by Daimler, the company “has already informed the relevant authorities of these facts and will also make the results of this investigation available to all relevant associations as well as to other vehicle manufacturers.”