Update: Car engineers pour cold water on Daimler refrigerant fire claims

29 April 2013 | By Andrew Gaved

Car engineering research group SAE International has reported the conclusions of its extensive analysis of HFO 1234yf, calling the refrigerant “safe and effective to use in automotive applications” - free to view, simply register

The team on SAE’s Cooperative Research Programme, comprising most car manufacturers from Ford to Renault to Toyota, concluded that “the risk of passenger exposure to a vehicle fire associated with this refrigerant is exceptionally remote”.

The CRP was established to examine Mercedes owner Daimler’s claims that HFO 1234yf ignited in a staged head-on collision, whereas the previous refrigerant R134a, outlawed by the Mobile Air Conditioning directive, did not.

In the wake of lurid claims about the risk of flammability in the UK tabloid press, the SAE said CRP team members had again concluded that the refrigerant release testing conducted by Daimler is unrealistic, following numerous additional tests of various types to study ignition of an HFO 1234yf leak in a crash-damaged vehicle.

In another strongly worded statement, SAE said Daimler’s test “is not an appropriate test to verify the safety of refrigerant applications in vehicles. The Daimler testing did not include any actual vehicle collisions or the mitigating factors that occur in an actual collision.”

It said these factors include the quenching effect of front end compartment deformation, the extinguishing effect of steam released due to radiator breakage, and dispersion of the refrigerant from the condenser outside the engine compartment.

“Daimler’s refrigerant release apparatus and nozzle does not represent actual crash-damaged refrigerant lines, and was found to be artificial.”

The report was welcomed by Honeywell Fluorine Products, the manufacturer of the HFO, which emphasised that even those German manufacturers which have indicated they are in favour of using CO2 in the future cars had not found anything unsafe about the HFO.

Honeywell European managing director Paul Sanders said: “Pretty much all of the car industry has said publicly it can use 1234yf safely, including all members of the [German carmakers group] VDA, apart from Daimler. Opel had its test programme undertaken by engineering body TUV (above), which is globally respected.”

Following the report, Mr Sanders said Honeywell was now calling for the European Commission to censure Daimler for continuing to defy the MAC Directive. If strictly applied, the EC could forbid the registering of non-compliant cars, such as the Mercedes A and B class models which are still being produced with R134a, in contravention of the directive.

He said: “All we can ask is that the law is adhered to. The MAC directive is unequivocal that non-compliant cars should not be registered. The car industry has had seven years to make a compliant vehicle. HFO 1234yf is available today, it meets the MAC directive and it is cost-effective.”

Mr Sanders also claimed that Daimler’s preferred refrigerant carbon dioxide – which it has asked the EC for more time to develop – is not as environmentally friendly as HFO 1234yf across the lifetime of a vehicle.

He said: “CO2 is a smokescreen and it is three to five years away at best. As it is an asphyxiant it would need significant changes to car designs and the service charges would be higher, since if it was to leak, it would all leak at once.”

He warned that the Commission needed to take action against Daimler or risk appearing ineffectual: “It sets a dangerous precedent for the forthcoming F-Gas regulations if one company is allowed to go its own way and flout the law. Allegedly Daimler is saving 50 euros a car for not using 1234yf.  It is not a safety issue, it is a political issue.”