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Opinion

Higher Hydrocarbon Charge Limits: A Long and Winding Road The charge sizes and safety requirements for flammable refrigerants went through years of heated review before the IEC’s recent approval of 500g for A3 and 1.2 kg for A2 and A2L. But is there a new twist in the road?

— By Daniel Colbourne

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se of hydrocarbon refrigerants in commercial refrigeration systems has steadily developed over the past decade or so, but the technology h as b e e n h e l d b a c k by th e limi-tations on refrigerant charge size in the product standard, IEC (International Electrotechnical Commission) 60335-2-89.

The proposal included a number of protective measures intended to minimize the potential increase in flammability risk arising from the greater charge amount. These included:

That recently changed when the IEC approved a revision including a charge limit increase from 150 g to 500 g for A3 (hydrocarbon) refrigerants, and up to 1.2 kg for A2 and A2L refrigerants, used in self-contained cabinets.

Additional construction features

Releasable charge test Surrounding concentration test

Minimum height of refrigerantcontaining parts Minimum airflow

But the road to the new standard was long and winding. It began in July 2014 when the British National Committee circulated a draft for comment (61C/581/ DC), which was a proposal to increase the flammable refrigerant charge to above 150 g. This was motivated by a substantial number of commercial appliance manufacturers wanting to use larger R290 (propane) charge amounts.

Accelerate Magazine // June 2019

These were in conjunction with other measures intended to demonstrate the resilience of the system tightness.