This article is written by Daniel Robert, Senior Vice-President, Special Projects, and was published in GESTION IMMOBILIÈRE magazine. To read the full article in the magazine, you can access it via the following link: Gestion immobilière – N°4 – November 2025
The current phase-out of hydrofluorocarbon (HFC) refrigerants is motivated by their moderately high Global Warming Potential (GWP). The HVACR and refrigeration sectors have been engaged in a global transition for the past 30 years and at least until 2050. This transition implies that the majority of companies in these sectors will be using “fourth generation” refrigerants, as illustrated in Figure 1. However, some segments of the industry are already turning to the “new generation” of ultra-low GWP refrigerants. Unfortunately, regulatory hurdles are limiting their adoption, mainly with regard to their safe use.
A significant reduction in GHG emissions was applied in 2024 in the USA and 2025 in Canada. This will be followed by a further reduction in 2029, before the final stage in 2036, which will bring emissions down to 15% of the initial reference level. The European Union, on the other hand, has a much more aggressive timetable for the complete elimination of GHGs.
First-generation refrigerants were simply working fluids in mechanical refrigeration systems, and many of them were characterized by rather high toxicity and/or flammability. Second-generation CFC refrigerants (e.g. R-11 and R-12) were used because of their increased safety thanks to lower toxicity and non-flammability, but were phased out because of their impact on the ozone layer. Third-generation HCFC (such as R-22) and HFC (such as R-134a and R-410A) refrigerants had low ozone-depleting potential, but were considered potent GHGs.
The transition to fourth-generation refrigerants (such as R-454B, R-32, R-513A, R-515B) offers industry options with no ozone-depleting potential and low to moderate GWP. Industry owners and end-users looking to move directly to the next generation of refrigerants are motivated by the need for ultra-low GWP options. Interestingly, these refrigerants offer a short list of options that were used in the first generation. So we’re seeing a return to basics.
WHAT ARE ULTRA-LOW PRP (GWP) REFRIGERANTS AND WHY THE GROWING INTEREST?
Since 2010, the United Nations has classified ultra-low GWP refrigerants as having a GWP of less than 10, a very low GWP of less than 100, a low GWP of less than 300 and a moderate GWP of less than 1,000.
The industrial sector seeking ultra-low GWP refrigerants includes, in most cases, government owners, large building owners and end-users with ambitious climate commitments. They are actively striving to reduce their refrigerant emissions and are looking to further reduce operational carbon.
WHAT ARE SOME EXAMPLES OF ULTRA-LOW PRP (GWP) REFRIGERANTS AND WHAT ARE THE OBSTACLES TO THEIR USE?
Table 1 shows several examples of ultra-low GWP refrigerants, together with dice indicators of the associated safety risks, dictated by ANSI/ ASHRAE 34-2024, Designation and Safety Classification of Refrigerants Taking into Account the Toxicity and Flammability of Individual Refrigerants. The table also includes quantitative measurements of the Occupational Exposure Limit (OEL), Refrigerant Concentration Limit (RCL) and Lower Flammable Limit (LFL).
Most ultra-low GWP refrigerants present higher risks in terms of flammability, toxicity, or both. These include hydrocarbon refrigerants (categorized as A3), notably propane, butane and isobutane. Their use has recently expanded in applications such as domestic refrigerators, refrigerated vending machines and bottle coolers, as well as refrigerated supermarket counters, in Europe, Asia and North America.
Driven by increasingly stringent energy standards, the manufacturers of these products have chosen isobutane and propane for their ability to meet these standards cost-effectively while maintaining an extremely low refrigerant charge, a guarantee of safety.
WILL THE USE OF HYDROCARBON REFRIGERANTS IN REFRIGERATORS BE EXTENDED TO AIR-CONDITIONING PRODUCTS?
In Europe and Australasia, hydrocarbon-based air conditioners have been developed and are used in homes and small commercial buildings. Already in Europe, air-cooled chillers weighing over 100 tonnes are operating on propane. In the USA and Canada, the use of hydrocarbon refrigerant systems in HVAC systems is restricted by the limitations imposed by ASHRAE 15-2024, as well as by model codes such as CSA-B52-2023, which adopt or adapt the provisions of ASHRAE. It should be noted that ASHRAE 15-2024 authorizes the use of hydrocarbons in refrigeration units, but the quantities allowed are so small (in the order of 100 to 150 g) that they are unsuitable for large-capacity systems. There are a few exceptions, but in general, North American regulations do not favor the use of ultra-low GWP hydrocarbon refrigerants… Pity!
DOES ASHRAE 15-2024 ALLOW THE USE OF OTHER ULTRA-LOW PRP (GWP) REFRIGERANTS?
Yes, the standard contains well-established requirements for A1 and B1 group refrigerants, and new requirements for A2L group refrigerants. As shown in Table 1, ultra-low GWP options are available in these safety groups, and their deployment is permitted.
Conclusion
As professionals, we have an obligation to give paramount importance to the safety of our buildings’ occupants.
Given that many ultra-low GWP refrigerants, such as hydrocarbons, are highly efficient and economically viable, but are also highly flammable, it will be essential to refine the ASHRAE 15-2024 and CSA-B52 standards, among others, in order to properly regulate their safe use in the building sector, as quickly as possible.
Currently, government agencies, national laboratories, non-governmental organizations, ASHRAE, equipment manufacturers, owners and others are joining forces to carry out the research necessary for the safe application of A3 refrigerants. The research should provide the technical basis for revised safety standards, which in turn will feed into model codes. Note that this transition to refrigerants dates back to several refrigerants first used in mechanical refrigeration systems in the 19th century. Our challenge today is to ensure their responsible and safe use for the foreseeable future. The future of our planet depends on it!
References:
– Real Estate Management article; https://jbcmediakiosk.milibris.com/reader/b389d544-4734-4814-91ad-f8ad61c9365b?origin=%2Fgestion-immobiliere%2Fgestion-immobiliere%2Fn3-2025