A2L Transition & Code Updates

Today, the intense desire of governments to move rapidly forward with implementing a low carbon economy means the regulatory burden placed on the HVAC/R industry including manufacturers, wholesalers, contractors, technicians, and a variety of other stakeholders amplifies the need for improved communication from governments to the governed. HRAI provides up to date industry information along with government and industry advocacy. We are currently involved in several regulatory arenas, such as: Amendments to the Energy Efficiency Act, The Canadian Registration Number (CRN) required for most pressure equipment in Canada, and the transition to A2L refrigerants. 

Of all, the transition to A2L “mildly flammable” refrigerants has enormous regulatory impacts. Scientists continue to search for ideal refrigerants that are non-ozone depleting, have zero ODP, are non-toxic and non-flammable, but, in the interim, a decision was made to phase down unacceptably high GWP products like R410A.   

Adopting A2L refrigerants affects several codes and manufacturing standards.  Advances in building science, construction technology, safety practices and the need to remain in consistent conformity with other codes such as the National Fire Code or National Plumbing Code require a review and update of the NBC every 5 years.  The review process requires input from a variety of stakeholders such as engineers, safety experts, building professionals and members of the public. All these groups gather to supply input and feedback on proposed changes to the code. 

HRAI along with the Air Conditioning, Heating, & Refrigeration Institute (AHRI) formed a working group last year to examine the impact A2L refrigerants will have on various codes such as the NBC, NFC and the B52 among others.  We have already submitted comments to the NRC concerning code changes related to the adoption of A2L’s and there will be more to come. 

As it pertains to the B52 code, the latest version was published in 2018, one year prior to the ASHRAE 15 standard. Thus, the current B52 is not up to date with the 2019 version of ASHRAE 15.  The B52 is on a five-year cycle, next publication date will be near the end of 2023. Our CSA B52 committee is actively examining further B52 code updates to deal with A2, A2L and A3 refrigerants.   

  • B52 is being updated to align with ASHRAE 15-2022 and most of the Addendums. At this point, 15.2 has not been included in the update. 

  • B52 is being updated to reference ASHRAE 34-2022 rather than keeping its own refrigerant tables. 

  • As of 1st January 2024, UL 60335-2-40/CSA C22.2 No. 60335-2-40 will replace all these standards, becoming the primary/harmonized standard for HVAC equipment in North America 

  • Products certified to earlier standards will not be grandfathered to UL 60335-2-40, meaning both new and existing products will eventually need to be tested to the new standard. 

  • Electric heat pumps, hot water heat pumps, air conditioners, dehumidifiers, and hydronic fan coils units utilizing refrigerants classified A2, A2L, or A3 per ASHRAE 34 shall not be certified to UL 1995 or CSA C22.2 No. 236. 

  • Equipment utilizing these refrigerants must be certified to a more rigorous UL 60335-2-40 / CSA C22.2 No. 60335-2-40 

Here is a look at the tentative dates for public input relating to the National Building Code review process.  

Public Reviews 


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There are a total seven public reviews planned. There are 3 fall reviews, occurring in October, November and December of the year, in 2022, 2023 and 2024. 

There are 2 winter public reviews, occurring in February, March and April of the year, in 2023 and 2024; and there are also 2 spring reviews, in May, June and July of the year, in 2023 and 2024. 

Public review documents are made available through announcements made in Construction Innovation (NRC-IRC's quarterly newsletter, which is posted at: 

and on the National Code Documents Web site at

The Internet is the primary format for distribution of public review information and receipt of comments. 

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