A2Ls 101: What You Need to Know to Handle A2Ls Safely
By Don Gillis, Senior Technical Trainer, The Chemours Company
Following best practices that have been in use for decades is the foundation for safe handling of A2Ls. A2L equipment is also being manufactured with technology to support mitigation steps due to their mild flammability.
For quite some time the HVAC industry has been hearing that A2L refrigerants “are coming.” This is no longer the case. The industry’s transition away from legacy hydrofluorocarbon (HFC) refrigerants to hydrofluoroolefins (HFOs) — and A2Ls especially — is in full swing. In fact, we expect to see A2L refrigerants like R-454B replace R-410A in new residential airconditioning systems this year. In commercial refrigeration, multiple OEMs have selected A2L replacements such as R-454A and R-454C, which stand to become major refrigerant products. Change is coming fast, necessitating that technicians get up to speed on A2Ls as quickly as possible.
As part of Chemours’ efforts to ensure that the industry has the knowledge to work safely and confidently with A2Ls, I spend about 35 weeks during the year traveling across the country providing A2L training courses and interacting with installers, technicians, and distributors, listening to and addressing their concerns. Below is an overview of key points I cover to help you prepare for working with A2Ls.
Why We Have A2Ls
In essence, A2Ls are the industry’s solution to the high global warming potential (GWP) of legacy HFCs. Once HFCs’ potential to significantly contribute to global warming was discovered, chemists created HFOs. Like HFCs, HFOs have zero ozone depletion potential and they offer similar operation and performance properties. However HFOs break down more quickly in the atmosphere while offering strong stability in HVAC systems.
To understand A2Ls’ potential positive impact on global warming, consider R-134a, which has an atmospheric lifetime of 13 years and a GWP of 1,430. HFO-1234yf — a component of many A2Ls — has an atmospheric lifetime of 10 days and a GWP of less than four. Refrigerant blends tell a similar story. R-410A, an HFC blend of R-32 and R-125, has a GWP of 2,088. R-454B, an A2L blend of R-32 and R-1234yf, has a GWP of 466.
As HFC production and consumption phasedowns continue under the American Innovation and Manufacturing (AIM) Act, and as technology transitions begin limiting the use of HFCs in specific technology sectors and subsectors, A2L usage and importance will grow. A2Ls are here to stay, making it critical that everyone in the industry is prepared to install and service A2L equipment.
A2Ls represent the new-generation refrigerant solution for a greener future, offering zero ozone depletion potential and significantly lower global warming potential compared to legacy HFCs.
American Society for Testing Materials results demonstrate the difference in flammability between A1, A2L, and A3 refrigerants. These photos indicate that A2Ls are much closer to nonflammable A1s than they are to highly flammable A3s (hydrocarbons).
Flammability Comparison
A2Ls are named for their ASHRAE safety classification of mild flammability and nontoxicity. Interestingly, when A2Ls were innovated, this classification didn’t exist. It was created because the refrigerants were slightly more flammable than A1s, but not as flammable as A2s, and far less flammable than A3s. To summarize:
A1s: Do not propagate a flame.
A2Ls: Mild flammability and slow flame propagation (burning velocity of A2L’S – less than 10 cm/sec.)
A2s: Lower flammability and faster flame propagation (burning velocity of more than 10 cm/sec.)
A3s: Higher flammability and faster flame propagation (burning velocity of more than 10 cm/sec.)
One big misconception I encounter is that A2Ls contain propane — which is not true. Compared to A3s (hydrocarbons), A2Ls are less likely to form flammable concentrations and are harder to ignite.
Working Safely and Confidently with A2Ls
The goal of training is to make sure everyone has the tools to work safely. Three key points I lead with during training are:
1. A2L standards require you to continue safety best practices you’ve been using for years or even decades and to adopt procedures for mildly flammable refrigerants. This holds true whether you’re installing new equipment or servicing existing systems.
2. A2Ls are only for new equipment. Currently, there are no retrofit applications.
3. Mixing A2Ls with A1s is unsafe, potentially harmful to equipment and performance, and illegal.
A2L equipment and tools are designed to support their safe use. Here are just a few examples: HVAC systems using A2Ls are manufactured with leak detectors. A flammability label is required on A2L equipment, products, and literature. A2L cylinders have a red stripe and opposite-side threading to prevent mixing with A1s. Cylinders also have a safety relief valve instead of a rupture disc.
In terms of working with A2Ls, my golden rule for safety is to now consider what had been best practices as required.
Here’s a preliminary checklist:
New equipment installation.
Read OEM manuals, follow lockout/tagout procedures, verify no voltage is present, ensure the area is well ventilated, have a 10-foot work perimeter, and evaluate the work area for ignition sources, flammable vapors, confined spaces, and clear exit points.
Recovery.
Use proper PPE and lockout/tagout, have a 10- foot work perimeter, do not vent or mix A2Ls with A1s, use A2Lrated tools, recover all refrigerant before opening the system, and use and label A2L recovery cylinders and don’t exceed their fill rate.
Service/repair.
Follow OEM literature, only use OEMapproved A2L replacement parts, use inert gas to remove residual refrigerant, ensure equipment is grounded, use a proper capacitator discharge method and nitrogen before and after brazing, install new liquid line filter driers, recharge the system by weighing in charge, and document information inside the equipment door.
Transporting A2Ls in your service truck is business as usual. Regardless of the hazard, 440 pounds is the total weight of combined materials and packaging that can be transported in a service van as a “Material of Trade.” Special placards and ventilation are not required. If the weight of finished goods containing A2Ls is less than or equal to 26.4 pounds, HAZMAT protocols are not needed, and there’s no limit to the number of cylinders you can transport. A2Ls can also be transported on their side if the cylinders indicate the manufacturer obtained a special permit.
Conclusion
What I’ve shared here offers a basic overview to get you started on understanding and feeling comfortable working with A2L refrigerants. A wealth of educational resources and training opportunities are available from companies like Chemours, as well as associations including AHRI, ESCO, RSES, ACCA, and others. Engaging in A2L training and continuing education is the best strategy to ensure that you and your crew are handling A2Ls safely and effectively with every installation and service call.
For more than 30 years, from service technician to territory sales manager to a national senior training specialist, Don Gillis has built experience and knowledge in the HVACR industry. He began his national training career while working for Emerson, conducting training sessions for thousands of HVACR professionals across North America. Don holds a Journeyman license for HVACR and sits on several committees including The SkillsUSA Nationals HVACR. At Chemours, he plays a vital role by helping to educate the industry through the transition to A2L refrigerant solutions
