CFC, HCFC, HFC and HFO: telling refrigerant families apart
A refrigerant's family comes from its atoms. Chlorine with no hydrogen makes a CFC, the worst for ozone. Add hydrogen and it's an HCFC, which breaks down sooner and does less harm. No chlorine at all makes an HFC or HFO: no ozone harm, but HFCs still warm the climate strongly.
From the lesson Refrigerant Families, ODP and GWP
Why it matters on the exam
The Core section expects you to classify a refrigerant from its makeup, and to know which families the rules phase out. The phaseouts follow ozone depletion potential first and global warming potential second.
Key points
- Chlorine harms ozone. One chlorine atom in the stratosphere can destroy many ozone molecules. Fluorine and hydrogen do not.
- ODP against CFC-11. Ozone depletion potential is measured against CFC-11, which is 1. HCFCs sit well below 1, HFCs and HFOs at 0.
- GWP against carbon dioxide. Global warming potential is measured against CO2, which is 1. HFCs run into the thousands, HFOs into single figures.
| Family | Chlorine | Ozone harm | Example |
|---|---|---|---|
| CFC | Yes | High | R-12 |
| HCFC | Yes | Low | R-22 |
| HFC | No | None | R-134a |
| HFO | No | None | R-1234yf |
Sort these refrigerants into their families
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Drag each card into its box, or tap a card and then a box.
Common trap
Assuming zero ozone depletion means harmless. HFCs have none, yet the AIM Act phases them down because of their global warming potential.
Question 1 of 5
Which family has an ozone depletion potential of zero but a high global warming potential?
Tap an answer and I’ll tell you why.
Question 1 is written for this page and checked by a person. The others are practice questions from the MindMax app. None are from a past exam.
Where it comes from
Lesson 2 in Ozone, Climate and Refrigerant Chemistry · Core Section
Refrigerant Families, ODP and GWP
- Classify a refrigerant as a CFC, HCFC, HFC or HFO from its chemical makeup
- Define ozone depletion potential as a value relative to CFC-11
- Define global warming potential as a value relative to carbon dioxide
- Explain why HCFCs have a lower ODP than CFCs
- State that HFCs have zero ODP but non-zero GWP
Key terms in this lesson
- CFC
- A chlorofluorocarbon: chlorine, fluorine and carbon, no hydrogen. The most ozone-depleting family, such as R-12.
- Global warming potential
- A gas's warming effect over time, measured against carbon dioxide, which is 1.
- HCFC
- A hydrochlorofluorocarbon: a CFC with hydrogen added, so it breaks down sooner and harms less ozone, such as R-22.
- HFC
- A hydrofluorocarbon: no chlorine, so no ozone depletion, but a high global warming potential, such as R-134a.
- HFO
- A hydrofluoroolefin: no chlorine and a very low global warming potential, such as R-1234yf.
- Ozone depletion potential
- A refrigerant's power to destroy ozone, measured against CFC-11, which is 1.
Learn more
FAQ
An HCFC. It contains hydrogen as well as chlorine, fluorine and carbon. New R-22 hasn’t been made or imported in the US since 1 January 2020, so servicing relies on recovered and reclaimed stock.
No. HFCs contain no chlorine, so their ozone depletion potential is zero. They are strong greenhouse gases, though, which is why the AIM Act phases them down.
CFCs, such as R-11 and R-12. CFC-11 is the reference every other refrigerant is measured against, with an ODP of 1.