A2L Refrigerants in Commercial Refrigeration Applications

A2L encompasses a class of refrigerants that have lower toxicity and flammability than A2 or A3 refrigerants, as listed by the American Society of Heating, Refrigeration, and Air Conditioning Engineers (ASHRAE) in ASHRAE Standard 34 (2019).

Compared to “highly flammable” A3 refrigerants, A2Ls are less flammable, as measured by three flammability criteria: 1) Higher lower flammability limit (LFL), meaning that it is less likely to form flammable concentrations; 2) Lower minimum ignition energy (MIE), meaning that it requires an open flame or strong electrical energy source to sustain an ignition; 3) Lower heat of combustion (HOC), meaning that it has a lower severity of ignition events.

It’s important to remember that individual A2L refrigerants will have varying degrees of flammability or global warming potential (GWP).

As of June 2021, A2Ls have been approved by the Environmental Protection Agency’s (EPA) Significant New Alternatives Policy (SNAP) Rule 23 for use in residential AC applications. Although the EPA has not yet approved A2Ls for use in commercial refrigeration, industry stakeholders expect further guidance and SNAP approvals in the near future. A2Ls have proved to be operationally safe and effective for commercial refrigeration applications in Europe and other regions.

A2L refrigerants offer unique thermodynamic properties and excellent performance characteristics that are similar to or better than common A1 HFC refrigerants such as R-404A or R-448A. Because performance characteristics will vary depending on the application, it’s important to check with Emerson’s application engineers to determine the optimal A2L refrigerant for your specific application.

A2L refrigerants are subject to refrigerant-specific charge limits based on the lower flammability limit (LFL) of each refrigerant. These are among the first of many mitigation strategies when using flammable refrigerants. Per a recent update to the second edition of the UL 60335-2-89 safety standard, A2L charge limit guidelines have been established for self-contained and remote refrigeration systems. For cases, charge limits are determined on whether equipment has an open design (without doors) or a closed design (with doors or drawers).