What are A2L Refrigerants?
Primarily used in air conditioning and commercial refrigeration systems, A2L refrigerants belong to a class known for their efficiency and lower environmental impact. The designation “A2L” comes from the ASHRAE safety classification, where:
- “A” indicates low toxicity.
- “2” signifies flammability, though at a lower level than class 3 refrigerants.
- “L” stands for low burning velocity, meaning the rate at which they burn is much slower compared to other flammable substances.
Regulatory Landscape
- In the U.S., the EPA regulates refrigerants under the AIM Act, phasing down HFCs via an allowance and allocation program.
- A2Ls are included in the list of acceptable alternatives under EPA’s SNAP program for specific applications.
- International regulations (e.g., F-Gas Regulation in the EU) have already accelerated A2L adoption due to stricter GWP limits.
How They Measure Up
ASHRAE Class |
GWP |
Application |
Composition |
|
R-454C |
A2L | 148 | R404A Replacement |
78.5% R1234yf / 21.5% R32 |
R-513A |
A1 | 573 | R134A Replacement |
56% R1234yf /44% R134a |
R-515B |
A1 | 299 | R134A Replacement |
91.1% R-1234ze / 8.9% R-227ea |
R-744 |
A1 | 1 | Low & Med Temp Ref |
Carbon Dioxide |
R-717 |
B2 | 0 | Low & Med Temp Ref |
Ammonia |
R-290 |
A3 | 3 | Low & Med Temp Ref |
Propane |
Comparison to Other Refrigerants
- Compared to CO₂ (R-744), A2Ls operate at lower pressures.
- CO₂ is non-flammable but requires complex controls and high-pressure equipment.
- Compared to A3 refrigerant, A2Ls allow larger charge sizes and can be used in more applications due to reduced flammability risks.
R454C Refrigerant
ENVIROMENTALLY FRIENDLY
EPA’s Push for Lower-GWP Refrigerants: A Milestone in Climate Action
The Environmental Protection Agency (EPA) has proposed new global warming potential (GWP) limits for refrigerants, with the goal of reducing the production and consumption of hydrofluorocarbons (HFCs). This means that by January 1, 2026 refrigerants used in new equipment must have a GWP of no more than 700
The EPA estimates that the proposed rule could reduce CO₂ equivalent emissions by up to 903 million tons from 2025 to 2050.
Hydrofluorocarbons (HFCs) high GWP means that they contribute significantly to the greenhouse effect. The EPA’s phasedown of HFCs is expected to reduce emissions by 4.6 billion metric tons of CO2 equivalent between 2022 and 2050—a reduction comparable to removing over 25 million railcars worth of coal from the energy mix.
THE BENEFITS
The Advantages of A2L Refrigerants: Efficiency, Compliance, and Safety
- Significantly Lower GWP: A2L refrigerants like R1234yf offer up to a 99% reduction in Global Warming Potential (GWP) compared to traditional refrigerants like R134a.
- Regulation Compliance: A2Ls are an attractive choice as environmental regulations [evolve], due to their very low or ultra-low GWP levels
- Similar Physical Properties to HFCs: A2L refrigerants have similar physical characteristics to HFCs, making them easy to use without adding system complexity.
- Compatibility with Existing Tools: Most tools used by installers for HFC systems can also be used with A2L refrigerants, reducing the need for new equipment.
- Safety in Application: Although classified as “mildly flammable,” A2L refrigerants are difficult to ignite, making them a safe option for refrigeration, air conditioning, and heat pump applications.
Thermodynamic Properties
- Operating pressures are similar to existing HFCs, allowing relatively straightforward system design adaptations.
- A2Ls typically offer comparable efficiency relative to high-GWP HFCs.
- They support larger system capacities due to more permissive charge limits compared to Class 3 refrigerants.
Application and Use Cases
- A2Ls are used in industrial and commercial refrigeration, residential and light commercial air conditioning, and transport refrigeration.
- Equipment design must address refrigerant containment, airflow, leak detection, and automatic shut-off control.
- Transition from HFCs to A2Ls require component replacement and technician certification.
- Manufacturers are releasing A2L-compatible compressors, heat exchangers, and system components.
Design and Maintenance Considerations
- System designs must limit the risk of refrigerant accumulation in case of leaks.
- Installation must ensure proper ventilation, sensor placement, and shutdown sequences.
- Technicians must be trained in A2L-specific handling procedures.
- Ongoing system monitoring is essential due to the odorless nature of A2Ls and mild flammability.
A2L Refrigerants: What You Need to Know
A2L refrigerants are a class of mildly flammable (A2), low-toxicity (L) refrigerants. They are part of a newer generation of refrigerants designed to reduce environmental impact while maintaining reliable performance in commercial and industrial refrigeration systems.
Certain hydrofluoroolefins have double bonds that enhance the flammability of olefinic compounds because of their reactivity and the energy released during combustion. However, the arrangement of fluorine atoms around these double bonds can reduce flammability. Additionally, the position of the double bonds within the molecular structure influences the burning velocity and flammability limits.
With a lower GWP than many traditional refrigerants, A2L refrigerant options provide companies a smart way to reduce their environmental footprint while preparing for future regulations.
Yes—when used with proper safety measures. Although A2Ls are classified as mildly flammable, modern refrigeration systems are designed with built-in safety features such as:
- Leak detection sensors
- Electronic shut-off controls
- Ventilation or circulation systems
- Isolation valves
These measures help prevent, detect, and respond to leaks, keeping systems safe and compliant with applicable safety standards.
Yes, refrigeration systems using A2Ls must meet updated safety standards and may require certified technicians trained to install and maintain them. However, many components and control systems are already compatible with A2Ls, and manufacturers are providing clear guidelines for safe integration.
Higher charge limits compared to some other flammable refrigerants enable the design of larger-capacity systems. This added flexibility makes them well-suited for applications like centralized refrigeration setups serving multiple zones or walk-ins.
While CO₂ is a non-flammable refrigerant with ultra-low GWP, it operates at much higher pressures and may require more complex system designs. A2Ls strike a balance between performance, safety, and environmental impact, especially in systems where CO₂ may not be practical.
No. A2Ls are odorless, which is why leak detectors are essential. Sensors ensure that leaks are identified quickly, even if they are not detectable by smell.
The U.S. Environmental Protection Agency (EPA) regulates the production and import of high-GWP refrigerants under the American Innovation and Manufacturing (AIM) Act. Through an allowance allocation program, the EPA is gradually reducing the availability of traditional refrigerants and encouraging the adoption of lower-GWP options, such as A2Ls.
If you’re considering transitioning to A2L refrigerants, you should:
- Confirm system compatibility
- Plan for required safety features
- Work with certified professionals
- Stay informed on federal and local regulations
