What is the ODP of R-22 versus HFC refrigerants?

What ODP measures

Ozone Depletion Potential indexes a substance's ozone damage against CFC-11, defined as 1.0. The destructive agent is the halogen: chlorine and bromine atoms freed by UV in the stratosphere catalytically destroy ozone molecules by the thousand. R-22's single chlorine, tempered by a hydrogen that shortens its atmospheric life, yields 0.055 — about one-eighteenth of CFC-11, low enough to serve as a "transitional" substance for decades, high enough to be scheduled for elimination.

The values, by family

Zero ODP is not zero impact

US EPA states the mechanism plainly: HFCs have zero ODP because they do not contain chlorine. That is why HFCs became the bridge away from CFCs and HCFCs. But zero ODP says nothing about climate — the same HFCs carry GWPs from 675 to 3,922, which is why the Kigali Amendment now phases them down (values and mechanics on the GWP page and in the Kigali guide). Modern refrigerant policy scores both axes at once.

Why this pairing matters in India

The two numbers explain the two regimes an Indian buyer navigates: R-22's 0.055 ODP is why its supply is quota-limited, registration-gated and servicing-only; the HFCs' zero ODP is why they face no such gate today and only a gradual CO₂e cap from 2028. When an auditor or customer asks "is your refrigerant ozone-safe?", the honest answer for every HFC line we stock is yes — and for R-22, that it is lawful, controlled, declining supply for existing equipment.

The proof the metric worked: ozone recovery

ODP is unusual among environmental metrics in having a visible success curve attached. Because the Montreal Protocol ranked and phased substances strictly by this number — CFCs at 1.0 first and hardest, HCFCs at a twentieth of that later and gentler — atmospheric chlorine peaked in the late 1990s and has declined since, and scientific assessments now project the Antarctic ozone layer's recovery toward mid-century on current compliance. That track record is why the ODP framework was trusted to carry the Kigali expansion: the same registration-quota-schedule machinery that retired CFCs is what now manages HCFC-22's descent and the HFC phase-down. It is also why the 0.055 number on R-22 should be read as neither trivial nor terrifying. Not trivial: multiplied across the tonnages a servicing market consumes, small ODPs aggregate into real stratospheric chlorine, which is why venting R-22 during service is both wasteful and genuinely harmful, and why recovery practice matters even for a 'low-ODP' gas. Not terrifying: 0.055 is the reason R-22 was granted a decades-long transitional role and a servicing tail to 2040 rather than a CFC-style hard stop — the regulatory system prices the harm proportionately. For an Indian buyer, the operational translation is simple: treat every kilogram of R-22 as accountable (registered purchase in, recovered gas out), and the metric that closed the ozone hole keeps working exactly as designed.

Related: GWP values · Is R-22 banned? · R-22 supply