2 Refrigerants and Environmental Regulations
Understand refrigerant families, environmental effects, safety classifications, identification practices, and the U.S. rules governing refrigerant use and servicing.
Refrigerant families and environmental effects
Refrigerants transfer heat in air-conditioning and refrigeration systems. Their environmental effects, operating properties, and safety hazards differ, so identifying the refrigerant correctly is essential before servicing equipment. A refrigerant number identifies a chemical or blend; it does not, by itself, state the refrigerant’s environmental impact or safety classification.
Families and examples
contain chlorine, fluorine, and carbon. R-12 and R-11 damage stratospheric ozone. Their production and import have been phased out in the United States, subject to limited exceptions.
contain hydrogen as well as chlorine, fluorine, and carbon. R-22 depletes ozone, though less than many . New production and import of most have been phased out, but recovered or previously produced refrigerant may remain available for servicing existing equipment.
contain hydrogen, fluorine, and carbon, but no chlorine. R-134a and R-410A do not deplete ozone, but many have high . U.S. law phases down their production and consumption.
are unsaturated fluorinated compounds often used as lower-GWP alternatives. R-1234yf is one example; some are mildly flammable.
Hydrocarbons and inorganic refrigerants include naturally occurring or simple compounds. Propane (R-290), isobutane (R-600a), ammonia (R-717), and carbon dioxide (R-744) can have low or zero ozone-depletion potential, but still require safety controls appropriate to the application.
Blends combine two or more refrigerants. A suffix such as the A in R-410A distinguishes a blend composition. Do not substitute one refrigerant for another based only on similar names or pressure: equipment is designed for specified refrigerants.
Identification and safety classifications
Read the label; do not identify a refrigerant by cylinder color. Check the refrigerant number and product name, the cylinder’s required hazard and transport markings, and the safety data sheet (SDS). Do not use a mislabeled cylinder or one whose contents are uncertain.
AHRI Guideline N recommends a common light gray-green paint color for refrigerant containers rather than a different paint color for each refrigerant. This is an industry recommendation, not a law, and older cylinders may still have legacy colors. Color is not a reliable way to confirm contents.
Toxicity and flammability classifications
ASHRAE Standard 34 assigns a safety group with a letter for toxicity and a number for flammability. A means lower toxicity and B means higher toxicity, based on occupational exposure limits. The flammability classifications are:
1: No flame propagation under the standard’s test conditions.
2: Lower flammability.
2L: A lower-flammability subclass with low burning velocity.
3: Higher flammability.
Examples include R-410A as A1; R-32 and R-1234yf as A2L; propane R-290 as A3; and ammonia R-717 as B2L. These classifications do not mean a refrigerant is harmless. Even an A1 refrigerant can displace oxygen, and high pressure, cold liquid, or decomposition products can cause serious injury. Follow the equipment maker’s instructions, applicable safety standards, and the SDS.
Ozone-depleting refrigerant controls
The is the international agreement to protect the ozone layer. In the United States, Clean Air Act Title VI implements controls on ozone-depleting substances. are generally phased out, and new production and import of most ended in 2020. This does not mean that every existing HCFC system must immediately be removed; refrigerant already available may be used for permitted servicing. EPA’s phaseout schedule includes remaining HCFC controls and exceptions.
HFC phasedown and substitute approvals
The American Innovation and Manufacturing (AIM) Act addresses . Although do not deplete ozone, they can be powerful greenhouse gases. The Act directs EPA to reduce HFC production and consumption to of baseline levels by 2036 through staged limits and an allowance program. This phasedown is not, by itself, a blanket ban on servicing every existing HFC system.
Separately, EPA’s Technology Transitions Program restricts certain HFC uses in specified product and equipment sectors. Some restrictions began January 1, 2025. Whether a refrigerant may be used depends on the end-use, equipment, and applicable rule provisions.
EPA’s Significant New Alternatives Policy () program evaluates substitutes for specific end-uses and lists them as acceptable, acceptable subject to use conditions, or unacceptable. An acceptable listing does not override a separate restriction under the or another applicable rule.
Recovery, reuse, and service requirements
Under , intentional venting of ozone-depleting refrigerants and most substitutes during service, repair, or disposal is prohibited. Section 608 also establishes technician-certification, recovery, and other service requirements.
Recovered refrigerant can be reused only as allowed by the rules. Refrigerant sold for reuse generally must be reclaimed to the required purity by an EPA-certified reclaimer. Limited regulatory exceptions exist, so requirements should be checked for the refrigerant and activity involved.