NOTE TO READERS: The author sits on both the ASHRAE 15 committee and the CSA B52 committee. The opinions in this article are solely those of the author and do not represent those of either committee.
I can’t help feeling like there is something of a paradox, or at the very least, some sort of incongruity between how long it takes to develop codes and rules compared to how often it feels those same regulations are changing.
Code and safety regulation development usually feels like a mind-numbingly slow process. The industry is changing quickly, and updates to new refrigerants are very frequent. The next phase of the transition to newer lower global warming potential (GWP) refrigerants is well underway and we are starting to see changes that have been in the works for over a decade come into effect quickly. There are plenty of high-level safety code updates and changes to the refrigerants themselves that are ultimately driving this change since we previously discussed this topic in July 2021.
A2L refrigerants
The GWP of R-410A is 2,088. This means that is it being phased-down in current F-Gas regulations in Europe and, although the path is less clear in Canada, it will catch up in the phase-down here as well. Because it has been very difficult to find replacement refrigerants with low GWPs that are not flammable, it has become necessary for the industry to transition to A2L refrigerants. This means new safety rules are necessary to accommodate their use.
ASHRAE 15 is the base standard that determines the installation requirements for most refrigeration and air conditioning systems in the U.S. It’s not adopted directly in many places, but its content is referred to by the UMC and IMC model codes throughout the U.S. Additionally, it is also referenced in installation in product listings. ASHRAE 15 has been working on rule changes to accommodate A2L refrigerants for over a decade and they continue to publish changes. ASHRAE 15 is republished every three years with the most recent edition published in 2019.
Since the 2019 publication, there have been a whopping 21 addenda! Compare that to seven for the 2016 edition, five for the 2013 and 2010 editions, and four for the 2007 edition, I think you get the point. A lot of that change has been made to accommodate A2Ls. A new edition of ASHRAE 15 is being published this year and, while the pace of addenda may slow down, there are already several in the works.
In my opinion, there are several challenges associated with the changes in ASHRAE 15 and how they treat A2L refrigerants. Fundamentally, the standard is relying on product listings such as UL 60335-2-40/CSA C22.2 No. 60335-2-40 to provide the safe design of the equipment and any associated leak detection equipment. Additionally, the primary focus has been on air conditioning applications for human comfort and chillers in machine rooms. This leaves out a lot of different applications this equipment could be used for. It also becomes challenging to rely on product listings for field built-up systems since they are often (and necessarily) one of a kind and can’t comply with a listing the way a factory product can. There is much discussion going on about these issues and I would expect more changes over the coming years.
Collaborating on standards
CSA B52 relies on ASHRAE 15 for some of its technical content, even with the standards diverging somewhat over the years. The Air-Conditioning, Heating, and Refrigeration Institute (AHRI) and ASHRAE have completed a huge amount of research into the safe application of these flammable refrigerants, and I would expect that CSA B52 will rely on the published changes in ASHRAE and the results of this research to develop changes for the safety standard used throughout Canada. CSA B52 is also on a planned publication cycle and will see a new version published in 2023. I expect there will be a lot of changes there to accommodate A2Ls as well.
Ultimately, because of the 3kg exemption and the lack of clarity in how B52 applies to residential installations, the equipment is likely going to precede the regulation changes here since it has become available in the U.S. This year saw the first R32 ductless split installed in North America and several others have been installed since. I do not keep up with state level regulations in the U.S, but I’m confident that several states have adopted recent regulations that allow the use of A2Ls and I’m sure more will follow as the code cycle progresses. The smaller packaged equipment has been available for a long time in Canada.
New classification
In case you haven’t kept up, A2L is a relatively new classification of refrigerants. The “A” means that it is low toxicity and the “2L” means it has a low flammability. For flammability, the old classification has only “1”, “2” and “3” classifications which were based on whether the refrigerant propagates flame, and if it does, its required ignition energy and its heat of combustion.
In other words, if it’s easy to light on fire and there is a lot of energy released when it burns, it is a “3” (e.g., propane, isobutane). If it’s flammable but doesn’t meet the requirements of a “3”, its a “2” (e.g., R-512A, R-465A), and if it doesn’t propagate flame, it’s a “1” (e.g., most common refrigerants in use today).
The addition of 2L added a class of refrigerants that would have previously been classified as a “2” but whose flame speed was less than 10 cm/s and reclassified them to “2L” (e.g., ammonia, R-1234yf, R-32). This was necessary so that rules could be developed that would allow the use of safer version of flammable refrigerants in systems that would not have previously been allowed to use them; all of this is being done to lower the GWP of the refrigerant.
Changes are coming in a lot of other ways as well. Unless there are rules developed to retrofit from A1 refrigerants to an A2L refrigerants, the transition from R-410a to A2Ls will necessitate A1 drop-in refrigerants to replace R-410A. Currently, two manufacturers have introduced A1 replacements with a lower GWP than R-410A. Honeywell introduced R-466A several years ago for use in new equipment. There may be some material compatibility issues and so far, the refrigerant has not been used widely in new equipment. R-470A was announced by Refrigerant Service Inc. (ComStar in the U.S.) as an A1 drop-in replacement in 2020 and has become commercially available in the U.S. as of this year; it was added to ASHRAE 34—the standard that designates refrigerants in both Canada and the U.S—in addendum “e” to the 2019 edition. It may interest you to know that R-470A is a six-component blend that contains none other than 10 per cent CO2. I expect there will be more drop-ins developed as the need for them draws closer.
Having been in the refrigeration industry from the tail end of the R-12 phase-out until now has been incredibly fascinating; while I understand the frustration that comes with change and what seems like a never-ending rainbow of refrigerant tanks in the trucks, I think the environmental progress is something we should be proud of.