DUH: High HF concentration measured in new HFC1234yf tests

By Klara Skačanová, Jan 22, 2014, 16:12 2 minute reading

Results of a new test revealed by the Deutsche Umwelthilfe (DUH) this week draw attention to the hazards of high concentration of toxic hydrogen fluoride (HF) in a situation where a car catches fire in a tunnel. Consequently, the DUH calls on the European Commission to perform further testing and urges carmakers to deploy CO2 as soon as possible. + VIDEO

The new test commissioned by the Deutsche Umwelthilfe (DUH) and performed by DMT, a subsidiary of TÜV Nord, adds to the growing evidence of hazards related to refrigerant HFC1234yf in mobile air conditioning (MAC) and brings a new perspective to the discussion on the EU Directive on Mobile Air Conditioning (MAC Directive).

Given the reconfirmed hazards, the DUH requests banning HFC1234yf and demands the fastest possible deployment of natural refrigerant CO2 in mobile air conditioning. “Alarming levels of hydrogen fluoride were found during the vehicle fire. Almost 45ppm was measured in the air – this concentration results in irreversible health damage only after a short time,” said international transport expert Axel Friedrich, who supervised the testing.

Concentration of almost 45ppm of HF measured after 5 minutes of fire

In order to simulate a realistic scenario whereby a car catches fire in spaces with limited air circulation, such as tunnels or underground garages, a tyre of a test vehicle was ignited and within a very short time the whole car burst into flames reaching a temperature of 800˚C. After about five minutes, concentration of HF was measured at the level of almost 45ppm (parts per million). In the period between 5 and 15 minutes after the fire started, on average 17ppm of HF was recorded. While the tunnel was mechanically ventilated, higher HF concentrations could occur in tunnels that are ventilated naturally. The charge of the refrigerant HFC1234yf in the mobile air conditioning of the tested vehicle before the fire amounted to 327g.

According to DMT, a 30 – 60- minute exposure to a concentration of 50ppm of HF would have fatal consequences for humans.

DUH: EC should conduct new tests to fully evaluate hazards of HFC1234yf

The DUH test confirms the risk not only for vehicle occupants, but also for fire fighters and emergency personnel even in situations when the vehicle fire is not directly related to discharge of HFC1234yf. This experiment brings a new perspective as until now the focus of other tests has been to evaluate the risk of HF formation after an accident, in contact of the refrigerant with hot surfaces or after its inflammation.

According to the DUH, many of the approximately 20,000 vehicle fires in Germany are caused by vandalism, cable defects, overheated brakes and tires or cross flames of other burning vehicles. These scenarios have so far not been considered in the safety analysis of the refrigerant. The DUH therefore calls on the European Commission to conduct new tests that take account of such situations in order to fully evaluate the hazards.


By Klara Skačanová

Jan 22, 2014, 16:12

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