Navigating the Transition to A2L Refrigerants

Navigating the Transition to A2L Refrigerants

In 2020 the American Innovation and Manufacturing (AIM) Act was signed into law, a bill aiming to reduce harmful, planet-warming pollutants emitted by refrigerators and air conditioners.

As the industry transitioned toward refrigerants with lower global warming potential and improved efficiency, it was discovered these alternatives are mildly flammable. To address this challenge, a new designation of A2L was created, prompting the industry to rapidly develop and codify proper safety precautions. In fact, the 2022 version of ASHRAE Standard 15, which serves as the basis for the 2024 International Mechanical Code (IMC), underwent so many revisions that an updated version was issued a full year earlier than the typical update cycle.

These rapid changes resulted in widespread uncertainty around the requirements for installing systems using these refrigerants. Even more confusing is that the majority of jurisdictions are still enforcing the 2021 IMC, which does not reference A2L refrigerants at all, leaving designers, contractors, and code officials navigating inconsistent and sometimes unclear guidance.

Evolving Refrigerant Safety Requirements: Changes in ASHRAE 15

For any refrigerant there are three general safety concerns:

• Limiting the amount of refrigerant (releasable charge) that could leak to minimize the possibility of suffocation.
• Setting the smallest size space (dispersal volume) into which the releasable change can leak into.
• Protecting the building from fire to ensure safe egress.

 

The 2022 version of ASHRAE 15 addressed these requirements as follows:

• The allowable amount of refrigerant per 1,000 cubic feet of space was reduced by almost 80% when compared to the previous generation of refrigerants.
• Normally unoccupied areas now must be considered when calculating the dispersal volume.
• There was no mention of packaged self-contained, or rooftop units.
• A ventilated and fire rated shaft was required for refrigerant piping passing through more than two floors of a building.

 

These requirements made it very difficult to apply A2L refrigerants. The 2024 version of ASHRAE Standard 15, however, provides the following relief:

• It allows the releasable volume of refrigerant to be reduced by the use of isolation valves that close when a leak is detected, allowing larger systems to be installed.
• It also allows the dispersal volume to be increased by combining rooms that are connected by a common, ducted, heating or air conditioning system; so long as the fan energizes when a leak is detected.
• The application of self-contained, packaged systems with less than 22 pounds of A2L refrigerant are no longer restricted if they are not installed in an egress path.
• Ventilated, fire rated, shafts are no longer required for refrigerant piping if the piping is properly tested.

There are additional technicalities in applying these rules. For example, the residential version of the standard, ASHRAE 15.2, only allows the elimination of ventilated shafts if there are no joints in the piping.

Understanding the Path Forward for A2L Adoption

The path forward is still murky because different jurisdictions recognize different versions of the building code; for example:

• Prince George’s County in Maryland explicitly requires rated and ventilated shafts, as does the City of New York.
• The District of Columbia has officially adopted the 2022 version of ASHRAE 15. However, they have been approving code modifications for the use of the 2024 version.

As the industry continues to navigate these evolving requirements, the path forward remains unclear due to varying code adoptions across jurisdictions. GPI has the knowledge and experience to apply A2L refrigerants in a code‑compliant manner regardless of location, and we are here to answer your questions and support your projects. We will also continue monitoring future regulatory developments, including the industry’s growing consideration of R‑290 (propane), a refrigerant with zero global warming potential.