A2L Refrigerants - Frequently Asked Questions

The EPA began the phasedown of Hydrofluorocarbon refrigerants including R-410A on January 1, 2022. As a result, the HVACR industry is transitioning to Low GWP Refrigerants including R-32, R-454B, and equipment that runs on them.

While HVACR professionals should educate themselves on the codes and standards for safe handling, storage, and transportation of these mildly flammable refrigerants (A2L), our customer service team has shared the most frequently asked questions they receive.

Q: Why the sudden transition away from HFC refrigerants?

A: This transition is not sudden! It has been progressing for some time.

• For the past few years, the air conditioning systems in our cars have operated with an A2L refrigerant, namely R-1234yf.
• The window units that we can buy anywhere have operated with R-32 since 2015.
• The refrigerators that we buy for our houses contain an A3 refrigerant, either R-290 (propane) or R-600a (isobutane).?

The transition has been slow, but now with the AIM (American Innovation and Manufacturing) Act of 2022, it's starting to speed up. There are over 100 million A2L units installed worldwide (including, Japan, and Australia) and they've been operating safely for the last decade. ?

When we (the U.S.) switched from R-22 to R-410A, the rest of the world was switching to R-32. So again, the transition is not new, it's just new to us.?

Q: Why does the industry keep changing refrigerants?

A: There are a couple of important reasons.

• As technologies change, equipment and refrigerants change to maximize energy efficiency, improve system performance, and reduce harmful greenhouse gas levels in our atmosphere.
• Quite often, refrigerant changes are in response to regulatory changes. In many cases, refrigerant and equipment manufacturers are not the driving force behind refrigerant change.?

Q: Has the industry adopted new standards for Low GWP Refrigerants, if so, when?

A: Yes, ASHRAE, NFPA, UL, and AHRI have all established new standards starting in 2019.

• ?As technologies change, systems and refrigerants change.
• As the GWP (global warming potential) of a refrigerant decrease, its flammability goes up. So, if there is a move to refrigerants with even lower GWP levels, building codes and design standards for refrigerants will likely have to change as well. ?

Q: Since these refrigerants are flammable, aren’t they dangerous to work with?

A: Yes and no. All refrigerants, if properly handled, contained, and stored, are safe. If best industry practices and procedures are followed, the possibility of a mishap or injury are very low. Any refrigerant can be dangerous if proper safety and service procedures are not followed. So, it’s extremely important to get the training you need to stay safe!

• ?Cars, which, for the most part, rely on gasoline (an A3 substance) to operate. Automobile technologies include safety protocols to keep us safe.
• Gas furnaces require that fuel be brought into the house to operate. Safety devices (rollout switches, a limit switches, pressure switches, auxiliary limit switches) are built-in to help ensure safe appliance operation.??
• A2L units are going to have safety in mind when they're designed. Details of these safety considerations can be found in UL Standard 60335-2-40.?

Q: What is LFL and why is it important?

A: LFL (lower flammability limit): The minimum concentration of a flammable substance that is capable of ignition when there is sufficient mixture with air.

• Expressed as refrigerant percentage by volume
• The lower the number, the greater the probability for ignition.
• R-290 has an LFL of 2.1%, which means when it reaches 2.1% of the air by volume, it can be considered a competent mixture, and will burn
• A2Ls have higher LFLs, so you need more of it (and more oxygen) to achieve a competent mixture
• R-32 has an LFL of 14.4%
• R-454B has an LFL of 11.8%
• A lot of energy is also required to ignite the fuel/air mixture.
• Refrigerant + Air + Ignition Source = Ignition = Not Easy?

Q: What happens if an A2L leaks?

A: The system will shut down.

• Refrigerant sensors are located on the evaporator and on the condenser.
• A refrigerant detection system (RDS) senses the presence of refrigerant.
• If enough refrigerant is detected, the system will be shut down.
• A2L refrigerants are very efficient and have high thermal (heat) transfer capabilities, so units typically contain less refrigerant than traditional systems. ?

Q: Is there a potential for ignition during installation or service?

A: Yes, but not likely. If the safeties are not bypassed, and proper field practices and processes are demonstrated, this should not be an issue.

• Ignition if a leak occurs. Safety devices and features are built into the A2L system to shut it down in the event of a leak.
• Ignition during service? If technicians are not putting a torch to a line charged with refrigerant that will not happen.
• Note: All refrigerants will burn under certain conditions, even A1s like R-410A.?

Q: What is active mitigation?

A: Active mitigation refers to physical actions that are employed by the system to reduce the concentration of refrigerant. Examples of active mitigation include:

• initiating a pump down cycle to trap refrigerant in the condenser.
• turning on the blower motor to move air through the space. ??

Q: Do I need to use different tools to service systems that operate with A2L refrigerants?

A: Yes. Some tools will need to be rated for use with A2L refrigerants. These tools include, but are not limited to gauges, vacuum pumps, and recovery machines.?

Q: Can you put an A2L refrigerant into an A1 system?

A: No. Retrofitting from one refrigerant safety classification to another is a violation of Environmental Protection Agency (EPA) SNAP Rule 23.

• You can't go from an A1 refrigerant to an A2L refrigerant
• You can’t go from an A2L refrigerant to an A1 refrigerant
• You may be able to reuse line sets, depending on local codes.
• If reusing line sets, you must be able to verify that they are clean.
• Be sure to pressure test all lines sets before using.

Q: Can you top off an A2L system, or do you have to completely remove the charge and replace it?

A: Yes and no.

• R-32 is a single component refrigerant, so topping off an R-32 system should not be an issue.
• R-454B is a refrigerant blend but has a very low fractionation potential and a very low temperature glide, so topping off an R-454B system should not be an issue.
• Composition doesn’t matter if there’s a known A2L refrigerant leak. If you must add refrigerant more than once in a three-year period, you have to find and repair the leak, pull a vacuum, pressure test, and then recharge the system. Any leaks are to be recorded on the permanent service log that’s attached to the unit. ?

Q: What are some of the differences between installing an A1 system and an A2L system?

A: The installation procedures for A2L and A1 systems are very similar. Many of the differences that do exist are pre-installation safety precautions that primarily involve evaluating the installation site. The space must be large enough, and have enough air, to keep the refrigerant charge at or below a percentage of the lower flammability limit (LFL) should the entire charge leak into the space. Always defer to the manufacturer’s installation guide and the authority having jurisdiction for specific installation requirements and guidelines as they can vary. ?

Q: Can I add A2L refrigerants to other refrigerants in my recovery cylinder?

A: No! Each refrigerant needs to be recovered into a separate recovery cylinder.?

Q:?Are there drop in refrigerants to replace R-410A?

A: No! Currently, there are no retrofit refrigerants on the market for R-410A.?

Q: How can I visually identify a system that operates with A2L Refrigerants?

A: Systems that operate with A2L systems will be clearly marked and labeled. For example, piping near system service ports (apertures) will be color-coded red. ?

Q: Do you still charge an A2L system using superheat and subcooling?

A: Yes. Technicians will still calculate superheat and subcooling

• There are maximum allowable charge limits for each system that cannot be exceeded.
• System literature will spell out the maximum charge and line set length.
• System components may need to be relocated to shorten the line set length.

Q: Are A2L refrigerants covered under EPA Section 608?

A: Yes. These refrigerants are still covered under Section 608, so they must be recovered.

• A3 refrigerants such as R-290 and R-600a are exempt.
• A2Ls are HFOs (hydrofluoroolefins) and are not exempt.
• Technicians will still need a license to purchase A2L refrigerants through a distributor. There may be additional state or local laws that must be followed. ?

Q:?Will the EPA Certification exam change?

A: No. However, the EPA does reserve the right to update the examination as they deem appropriate or necessary. ?

Q. What is happening with the petition submitted to EPA to ban R-410A in comfort cooling?

A. EPA is addressing petitions to limit the GWP of refrigerants in residential and light commercial air conditioning, and it is likely that the draft rule will be published before the end of 2022, proposing a 750 GWP limit in January 2025.?

Q. Will this Low-GWP transition only affect mini-split systems?

A.?The AIM Act will impact all refrigerant applications, including ducted split systems and packaged terminal air conditioners (PTAC).

Q: When will equipment that runs on Low GWP refrigerants become available?

A: A2L refrigerant and equipment is already available in many states. Check with your local code authority to find out when they will be permitted in your state. Then, check with your local distributor for availably information.?

Q. How do I know if my state allows the use of A2L (or A3) equipment?

A.?Contact the equipment manufacturer to inquire. Also, AHRI maintains a list of states that allow the use of low-GWP refrigerants (A2L, A2, A3) either through model codes or through legislative action. Visit their website: ahrinet.org ?

Q. Which manufacturers have decided on the refrigerant that they will use?

A.?Several manufacturers have noted that they will move forward with A2L refrigerants that are SNAP-listed for AC use. Those refrigerants are R-32, R-452B, R-454A, R454B, R-454C, and R-457A.

More details about which low-GWP refrigerants are SNAP-listed can be found on the Environmental Protection Agency’s?website.

Q: Will the manufacturers make any efforts to educate HVACR professionals on the transition?

A: Yes. AHRI, an association of manufacturers established the Safe Refrigerant Transition Task Force (SRTTF) to educate the industry on new standards. Free information and webinars are available here https://www.ahrinet.org/advocacy/safe-refrigerant-transition-task-force.?

Q: Do I need a special Low GWP Safety Certification to handle A2L refrigerants?

A: Subsection (h) of the Aim Act granted EPA the authority to regulate the phasedown of Hydrofluorocarbons and the management of substitutes. This empowered the EPA to initiate a rulemaking process, seeking industry input on technician training and certification requirements for handling ASHRAE 2, 2L, and 3 refrigerants. While the EPA is still gathering information, they have the authority to require special training and or certification. As more information is available, we will keep you apprised.

Q:?Where can I get trained on Low GWP Refrigerants?

A: There is a comprehensive course available on the HVACR Learning Network. https://hvacr.elearn.network/courses/A2L-Refrigerant-Safety

We also encourage you to watch these videos.