ODP (ozone depletion potential)
Also known as: ozone depletion potential
Short definitionA number showing how much a refrigerant thins the ozone layer, relative to R11. It is above zero for older gases that contain chlorine and zero for HFCs, HFOs and natural refrigerants.
The ozone layer filters the sun’s ultraviolet rays. Chlorinated refrigerants break this layer down in the atmosphere. On the ODP scale R11 is taken as 1; R12 is also 1 and R22 is 0.055. Starting in 1987, the Montreal Protocol phased these gases out step by step. Every refrigerant sold today has an ODP of zero, so regulations now look at GWP.
ODP is not a selection criterion for a newly built cold room. It comes up in old plants: there are still rooms in the field running on R22, and that gas is available only as reclaimed product. When quoting an extra unit or a refurbishment for such a room, read the existing refrigerant from the nameplate. A gas with zero ODP can still have a high GWP; they are two separate measures.