CEN/TR 14739:2004

The document gives a scheme for carrying out a risk assessment for flammable refrigerants in case of house-hold refrigerators and freezers with refrigerants of group A3 according to EN 378 1, taking into consideration a sealed system and a refrigerant charge of not more than 150 g. Sealed systems are refrigerating systems in which all refrigerant containing parts are made tight by welding, brazing or similar permanent connection.
NOTE  For risk assessment the method with flow diagrams is selected, because these are helpful for checking the possible ignition of the whole appliances and to estimate the probability of ignition. It takes EN ISO 12100, EN 1050, EN 1127, EN 60335 2 24/A53, E DIN 7003 into consideration.
At least the probability of deflagration is the product of multiplication of the probability of defects of different components and the probability for the presence of explosive atmosphere and the probability for the ignition sources.