New flammable refrigerants safety standard

After much delay the new version of BS EN IEC 60335-2-89[1] is available from BSI (BSI Knowledge). The standard covers commercial refrigerating appliances and ice-makers with an incorporated or remote refrigerant unit or motor-compressor and now includes safety assessment for appliances that have a flammable refrigerant charge of greater than 150 g. The new clauses which deal with systems that have more than 150 g of charge cover construction requirements and also a new test for leakage to determine gas concentration beyond the boundary of the appliance.

Previous versions of the standard only allowed refrigerant charges up to 150 g. These previous clauses remain, so all systems irrespective of their flammable refrigerant charge need to be safety tested.

The maximum flammable refrigerant charge that is allowed within the new standard is dependent on the refrigerant. The maximum charge allowed is determined by applying a calculation and can vary quite considerably depending on the flammability of the refrigerant.

New clauses dealing with construction are now included. These need to be assessed by inspection and physical testing and include several new requirements to minimise vibration of piping, test the protection of the appliance, ensure that solder alloys are safe and a requirement to ensure service ports comply with tightness control levels. A new room area safety clause is included which defines the smallest value of the room floor area limit for a system which must be marked on the appliance.

Additional physical testing is required to determine whether areas surrounding the boundary of the appliance are safe. This stipulates a controlled leakage test in defined test room conditions where the flammable gas concentration must not exceed certain levels.

To date most manufacturers providing appliances with flammable refrigerants have remained within the 150 g charge limit prescribed in previous versions of 60335-2-89. The new standard allows manufacturers to apply higher flammable refrigerant charges but does add extra testing requirements. Being able to apply a higher flammable refrigerant charge to appliances has significant advantages in terms of manufacturing cost. It also enables flammable refrigerants to be applied to larger appliances which in the past would have required 2 refrigeration circuits (with up to 150 g each) or where a non-flammable refrigerant would have been applied.

If you are interested in how the new standard can be applied to commercial refrigerating appliances and would like any advice, then please contact Alan Foster (alan.foster@rdandt.co.uk) at RD&T.

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