* Controversial refrigerant does not start fire in Opel SUV
* Testing agency says test done under extreme conditions
* Honeywell/DuPont's 1234yf is only EU-approved refrigerant
* Daimler says coolant can cause fire, but test
By Christiaan Hetzner
FRANKFURT, April 3 General Motors' German
brand Opel said on Wednesday that it had found no evidence in a
crash test on its new Mokka SUV that a controversial air
conditioning refrigerant could catch fire in a collision and
release toxic fumes.
Opel's domestic rivals Daimler and Volkswagen
are both developing expensive carbon dioxide-based
air conditioning systems in order to avoid what they say is a
fire hazard posed by Honeywell and DuPont's new
refrigerant HFO-1234yf, which emits poisonous hydrogen fluoride
gas when it burns.
Opel said a realistic test conducted together with the
independent testing agency TÜV Rheinland had failed to ignite
refrigerant that leaked from the system after impact.
The test is the first to be published since Daimler said in
September that 1234yf, the only air conditioning coolant on the
market that conforms to a new European Union directive on
greenhouse gases, could be the primary source for a vehicle
Many in the industry have questioned the relevance of
Daimler's test procedure, but its findings have nevertheless
rattled global carmakers, which had so far universally agreed to
employ the chemical. It could also cost the two producers of the
patented HFO-1234yf billions of dollars in lost investments and
The EU has ordered a phase-out of the widely used
refrigerant R134a because of its potency as a greenhouse gas.
Opel began installing 1234yf-based systems in its Mokka
model at the start of the year but Daimler is violating the EU
directive by continuing exclusively to use the non-flammable
Opel research and development chief Michael Ableson said
there was "no alternative in the near future to refrigerant
"Other possibilities such as CO2-based refrigerants are
still in the development stage and are years away from entering
the market," he said in the statement.
Daimler says frontal crash simulations that it conducted
internally last August showed that a fire could ignite under the
hood of a car when the new Honeywell refrigerant, mixed with air
conditioning lubricant, came into contact with the manifold of a
turbo-charged petrol engine at around 650 degrees Celsius (1,200
Opel said on Wednesday it had crash-tested a 1.4 litre
turbo-charged Mokka at a speed of 50 km/h (31 mph) against a
movable deformable barrier, meant to simulate driving headlong
into the last car in a tailback.
It said the impact had damaged the air conditioning system,
causing a leak near the Mokka's hot engine manifold, but without
causing a fire.
Gunnar Pflug, head of the traffic safety centre at TÜV
Rheinland, said the test had been designed and conducted under
TÜV Rheinland's supervision to recreate the extreme conditions
that Daimler says are necessary to induce a fire. It included
reaching an engine temperature more than 100 degrees Celsius
higher than that recorded by Daimler.
"Much faster speeds and there would have been nothing left
of the engine compartment, basically," he said. "What we did was
no standard test, this was the first of its kind."
Manufacturer Honeywell concedes that the mixture is indeed
flammable and releases toxic gases when burning, but argues that
Daimler's simulations employed 'ideal' conditions expressly
designed to create a desired effect.
Daimler, Mercedes' parent, says simulations as opposed to
real crash tests were necessary because each car deforms
differently during impact, even if the same test parameters are
Pflug said this was only partly true.
"The same parts are not always damaged exactly the same way
down to the millimetre, but if it isn't the third air
conditioning fin that breaks, then it's the second or seventh,"