How much a substance damages stratospheric ozone relative to CFC-11.
ODP rates ozone damage with CFC-11 set at 1. CFCs such as R-12 have high ODP, HCFCs such as R-22 have lower but non-zero ODP, and HFCs have an ODP of zero. Ozone-depleting refrigerants are phased out under the Montreal Protocol, which is why R-22 equipment is being retired or converted.
Exam work areas
A · Safety and trade practice