Refrigerant Classifications
& Properties

The Refrigerant Family Tree

Modern refrigerants are classified by their chemical composition into four main families. Understanding these classifications is essential - they determine ODP, GWP, flammability, regulatory status, and handling requirements.

CFC - Chlorofluorocarbons (Banned)

CFCs contain carbon, chlorine, and fluorine. The chlorine atoms are highly reactive with stratospheric ozone - one CFC molecule can destroy up to 100,000 ozone molecules through a catalytic chain reaction.

Refrigerant	Application	ODP	GWP	Status
R-11	Centrifugal chillers	1.0 (reference)	4,750	Banned - production ended 1996
R-12	Automotive, household refrigerators	1.0	10,900	Banned - production ended 1996
R-113	Large centrifugal chillers	1.0	6,130	Banned - production ended 1996

HCFC - Hydrochlorofluorocarbons (Being Phased Out)

HCFCs contain hydrogen in addition to chlorine and fluorine. The hydrogen makes them less stable, so they break down before reaching the upper atmosphere - resulting in lower ODP than CFCs. However, they still damage ozone and are being phased out under the Montreal Protocol.

Refrigerant	Application	ODP	GWP	Status
R-22	Residential and commercial AC	0.05	1,810	No new production since Jan 1, 2020. Reclaimed/recycled only.
R-123	Large centrifugal chillers	0.02	77	Being phased out; low GWP gives it extended use period

? R-22 Is Expensive and Scarce

R-22 production ended January 1, 2020. All available R-22 is recycled or reclaimed from existing systems. Prices have risen dramatically - often $50-$150 per pound. R-22 system owners face a choice: keep repairing or replace with R-410A equipment.

HFC - Hydrofluorocarbons (Current Standard)

HFCs contain no chlorine - zero ozone depletion potential. They replaced CFCs and HCFCs but have high GWP values, making them targets for phase-down under the Kigali Amendment to the Montreal Protocol.

Refrigerant	Application	GWP	ASHRAE Group
R-134a	Automotive AC, medium-temp refrigeration	1,430	A1
R-410A	Residential/commercial AC	2,088	A1
R-404A	Commercial refrigeration	3,922	A1
R-407C	R-22 retrofit refrigerant	1,774	A1

HFO - Hydrofluoroolefins (Next Generation)

HFOs contain a carbon-carbon double bond that makes them unstable in the lower atmosphere - they break down quickly, resulting in very low GWP. Zero ODP. The future of refrigerants.

Refrigerant	Application	ODP	GWP	ASHRAE Group
R-1234yf	Automotive AC (replacing R-134a)	0	4	A2L (mildly flammable)
R-1234ze	Chillers, heat pumps	0	7	A2L (mildly flammable)

ASHRAE Safety Classifications

Classification	Toxicity	Flammability	Examples
A1	Lower toxicity	No flame propagation	R-22, R-410A, R-134a, R-404A
A2L	Lower toxicity	Mildly flammable (LFL >3.5%, low flame speed)	R-1234yf, R-1234ze, R-32
A2	Lower toxicity	Flammable	R-152a
A3	Lower toxicity	Highly flammable	R-290 (propane), R-600a (isobutane)
B1	Higher toxicity	No flame propagation	R-123
B2L	Higher toxicity	Mildly flammable	R-717 (ammonia)

? Exam Tip

Memorize: R-22 ODP=0.05, phased out 2020. R-410A ODP=0, GWP=2,088, A1. R-1234yf ODP=0, GWP=4, A2L (mildly flammable). The ASHRAE A/B designates toxicity (A=lower, B=higher); 1/2/3 designates flammability (1=none, 2L=mildly, 2=flammable, 3=highly flammable).

Key Terms

ODP (Ozone Depletion Potential)

Relative measure of ozone damage compared to R-11 (ODP=1.0). CFCs have high ODP; HFCs and HFOs have zero ODP.

GWP (Global Warming Potential)

Heat-trapping ability relative to CO? (GWP=1) over 100 years. R-410A GWP=2,088 means it is 2,088 times more potent than CO?.

A2L

ASHRAE safety group for mildly flammable refrigerants with lower toxicity. LFL above 3.5% and low flame speed. Requires special handling vs A1.

? Overview Module 2: EPA Regulations ?