• Category Archives: A2L

New Refrigerants Transitional

The American Innovation and Manufacturing Act of 2020, or AIM was passed as part of the 2021 appropriation bill, passed on December 27, 2020. Although you probably would not know it from the title, the AIM Act is about phasing down HFCs. This is a phasedown, not a phase out. This table shows the phasedown schedule. Noite, we started the 60% of baseline period this year.  

AIM Act HFC Phasedown Schedule
Date% of Production Baseline% of Consumption Baseline
2020 – 202390%90%
2024 – 202860%60%
2029 – 203330%30%
2034 – 203520%20%
2036 –15%15%

Allowances

Because this is a phasedown and not a phaseout, some HFCs will still be available for a long time. However, ALL HFCs will not necessarily be available. The phasedown is regulated by assigning allocations for production and/or importing HFCs to producers and distributors. How quickly a company uses up their allocation is calculated by multiplying the quantity of HFC produced or used times its exchange value, which is basically its AR4 GWP. For example, R410A has an exchange value of 2088, R32 has an exchange value of 675, and R454B has an exchange value of 465. This means that a company can make 3 times as much R32 as 410A, or almost 4.5 times as much R454B as 410A.

Still Using HFCs?

One interesting situation is that the “new” refrigerants which will be replacing the current high GWP HFC refrigerants also contain HFCs. R32 is an HFC and it is on the list of refrigerants being phased down. Other alternatives being studied, such as R454B, are blends that contain R32. Phasing down R32 will eventually make both R32 and R454B not practical for equipment manufacturers. They will probably be replaced in ten years or less.

Making the Switch

HFC allowances are currently 60% of the baseline. If manufacturers continue to make exactly the same equipment with the same HFC refrigerants that they have been using, they will run out of their HFC refrigerant allowance before the end of the year. I believe most manufacturers will start producing R32 and R454B equipment this year. Just by switching from R410A to R32 a manufacturer can triple the amount of refrigerant they can use. Doing the math 60% x 3 = 180%. Suppose they used up half of their allowance on R410A before switching, that would be 30% x 3 = 90%. This means they could actually increase their overall production. The math is even better for R454B. 60% x 4.5 = 270%, or 135% if you had already used up half your allocation on R410A.

Down the Road 2029

Things get a bit tighter down the road in 2029 when HFCs are restricted to 30% of baseline. Now the R32 calculation is 30% x 3 = 90%, meaning you are restricted to less than the baseline for your entire production. The manufacturer will either have to use a refrigerant with a lower GWP or figure out a way to reduce the charge of the systems they produce. R454B looks a bit better with 30% x 4.5 = 135%, so you are still in business assuming you have not increased production a great deal and you are not using your HFC allocation for anything else.

Down the Road 2034

By 2034 manufacturers will definitely need to have more answers because the allocation drops to 20% of baseline. Now the R32 calculation is 20% x 3 = 60% and the R454B calculation is 20% x 4.5 = 90%: both fall short, and that is before accounting for any growth or using your HFC allocation for any other purpose.

Crystal Ball

In ten years or less I believe we will see systems using other refrigerants start to take over. At this point, I think the manufacturers are thinking HFOs. They are already widely used in car air conditioning and have very low GWPs. What remains to be seen is whether they will be widely accepted. The European Union is pushing back against fluorochemicals in general. They want “natural” refrigerants such as propane or carbon dioxide. Europe seems more comfortable with R290 in larger systems than we are in the US. I don’t think the added fire risk of R-290 is going to be accepted in larger systems in the US. I don’t believe CO2 is practical in smaller systems the size of residential air conditioners and heat pumps. Whatever the form, I believe in ten years we will be looking at very different equipment.  

A2L Guides, Standards, and Codes

The regulations regarding A2L refrigerant are found in a tapestry of Guides, Standards, and Codes which often refer to each other. Here is a list of the most consequential.

ICC International Mechanical Code 2024, IAPMO Uniform Mechanical Code 2024
These recently revised codes allow the use of A2L refrigerants in traditional HVAC systems. They specify conditions for use of A2L refrigerant and refer to ASHRAE Standard 15/34 2022 and UL 60335-2-40, 2022.

Amendments to ICC International Mechanical Code 2021, IAPMO Uniform Mechanical Code 2021
Some states have passed amendments to their existing 2021 codes to allow the use of A2L refrigerants in traditional HVAC systems and specifies conditions for use of A2L refrigerant. They refer to ASHRAE Standards 15/34 2019 and UL Standard 60335-2-40, 2022.

UL 60335-2-40, 2022
This is the latest standard from UL for HVAC systems. It is similar to the international IEC standard with the same name and number. The provisions in the IEC standard have already been in place in many other places around the world; including, Europe, Japan, and Australia. UL 60335-2-40 spells out in detail how A2L refrigerant may be safely applied. It refers to ASHRAE Standards 15/34 2022.

ASHRAE Standards 15 2022 “Safety Standard for Refrigeration Systems”
This standard describes how refrigeration systems may be safely installed and operated. The 2022 edition includes specific conditions for A2L refrigeration systems.

ASHRAE Standard 15.2 “Safety Standard for Refrigeration Systems in Residential Applications” Standard 15 addresses larger buildings while 15.2 describes how refrigeration systems may be safely installed and operated in residential low-rise applications, including specific conditions for A2L refrigeration systems.

ASHRAE Standard 34 – 2022 “Designation and Classification of Refrigerants” Standard 34 lists refrigerant safety ratings and important safety data for a long list of refrigerants, including several A2L refrigerants. Data listed in Standard 34 is used to determine specific system requirements detailed in Standards 15 and 15.2. Taken together, Standards 15 and 34 provide very clear guidance for application of A2L refrigerant.

EPA Final SNAP Ruling 23
This ruling specifically allows the use of A2L refrigerants R-32, R-452B, R-454A, R-454B, R-454C, and R-457A in new residential and light commercial air conditioners and heat pumps. The rule incorporates UL 60335-2-40 by reference.

EPA AIM Act Final Ruling, Sept 2021
This ruling establishes the HFC allocations for the phasedown of HFC refrigerants under the AIM Act. One unexpected significant component of this ruling is a ban on disposable refrigerant cylinders beginning in 2025.


AHRI Guideline M 2020 “Unique Fittings and Service Ports for Flammable Refrigerant Use”
AHRI Guideline M specifies that service connections for systems with flammable refrigerant. For cylinders holding less than 50 lbs. of A2L refrigerant, it specifies CGA 164 fittings which are 1/4 inch flare with left-hand threads. For equipment using A2L refrigerant it specifies 1/4 inch flare with right-hand threads, exactly the same as those used on systems with A1 refrigerant. Same size and same threads.


CGA Standard V-1 2019 “Standard for Compressed Gas Cylinder Valve Outlet and Inlet Connections” The CGA V-1 standard describes the connections on compressed gas cylinders. Standard CGA V-1 2019 introduces the CGA 164 connection specifically for A2L refrigerant cylinders. It describes the CGA 164 connection as a 1/4 inch flare with left hand threads. The latest edition of this standard is now CGA V-1 2021.

What is an HFO Refrigerant?

I have talked to many folks who wondered what exactly is the difference between HFC refrigerants, the refrigerants being phased down, and HFO refrigerants, the low GWP refrigerants that will be replacing HFCs in many applications. The puzzle is that HFOs are also HFCs. That is, they contain hydrogen, fluorine, and carbon. So why the different name?

Alphabet Soup

For many years we have used a sort of short-hand to describe a refrigerant based on the atoms in the molecule. CFC for the older chlorofluorocarbons containing chlorine, fluorine and carbon. HCFC for the Hydrochlorofluorocarbons containing hydrogen, chlorine, fluorine, and carbon. And more recently, HFC for the hydrofluorocarbons containing hydrogen, fluorine, and carbon. So it is natural to think that the O in HFO stands for a single chemical, but it doesn’t. Instead, the O stands for Olefin, which is a description of a hydrocarbon chain containing a double bond between two of the carbons. All our previous hydrocarbon-based refrigerants (CFCs, HCFCs, HFCs) were all built on hydrocarbon chains that used only single bonds. For example R-12 and R22 are methane molecules  while R-32, R-125, and R-134a are ethane molecules. HFOs (Hydrofluoro olefins) are based on carbon chains that contain a double bond between two of the carbons, in other words, an olefin. The most well known HFO R1234yf is based on propene. Notice the “ene” at the end. Hydrocarbons ending in “ane” are single bond molecules while hydrocarbons ending in “ene” have a double bond between two of the carbon atoms.

Why This Matters

So why is this important? The olefin based compounds break down much more rapidly in the air than their single bond cousins, which is how they achieve such low global warming numbers. Their calculated GWP is much lower because of their short atmospheric life. They don’t survive intact for long in the atmosphere. This reduced chemical stability is also why the HFO refrigerants are mildly flammable. So what is the difference between an HFC and an HFO? Basically the way they are put together.

A2L Refrigerant Standards and Regulations

The regulations regarding A2L refrigerant are found in a tapestry of Standards, Codes, and Rulings. I like to research using original documentation whenever possible. Not that I don’t trust the folks doing webinars, blogs, and videos, but when answering questions about new technology I want to be able to point to authoritative documents. So, I look for the actual standards, guidelines, and codes. I found it a bit confusing because there are so many agencies publishing many standards and regulations regarding A2L refrigerant. Furthermore, these standards often refer to each other. I have listed below some of the more important documents you should study if you like to do your own research.

ICC International Mechanical Code 2024, IAPMO Uniform Mechanical Code 2024
These completed but yet unpublished codes allow the use of A2L refrigerants in traditional HVAC systems and specify conditions for use of A2L refrigerant. They refer to AHRI Standards 15 and 34 2019 and UL 60335-2-40, 3rd edition.

Amendments to ICC International Mechanical Code 2021, IAPMO Uniform Mechanical Code 2021
Some states have passed amendments to their existing 2021 codes to allow the use of A2L refrigerants in traditional HVAC systems. Typically these amendments accomplish this by referring to AHRI Standards 15/34 2019 and UL Standard 60335-2-40, 3rd edition.

UL 60335-2-40, 3rd edition
This is the latest standard from UL for HVAC systems. It is similar to the international IEC standard with the same name and number. The provisions in it have already been in place in many other places around the world; including, Europe, Japan, and Australia. It spells out in detail how A2L refrigerant may be safely applied. It refers to ASHRAE Standards 15/34 2019.

ASHRAE Standard 15 – 2019 Safety Standard for Refrigeration Systems describes how refrigeration systems may be safely installed and operated. The 2019 edition includes specific conditions for A2L refrigeration systems.

ASHRAE Standard 34 – 2019 Designation and Classification of Refrigerants lists refrigerant safety ratings and important safety data for a long list of refrigerants, including several A2L refrigerants. Data listed in Standard 34 is used to determine specific system requirements detailed in Standard 15. Taken together, Standards 15 and 34 provide very clear guidance for application of A2L refrigerant.

ASHRAE Standard 15.2 – 2022 Safety Standard for Refrigeration Systems in Residential Applications is the low-rise residential companion to ASHRAE Standard 15. Standard 15 has historically primarily been applied to larger commercial buildings, not low-rise residential homes. Standard 15.2 describes in detail what must happen to safely use A2L refrigerant in a residential application.

EPA Final SNAP Ruling 23, April 2021
This ruling specifically allows the use of A2L refrigerants R-32, R-452B, R-454A, R-454B, R-454C, and R-457A in new residential and light commercial air conditioners and heat pumps. The rule incorporates UL 60335-2-40, 3rd edition by reference.

EPA AIM Act Final Ruling, Sept 2021
This ruling establishes the HFC allocations for the phasedown of HFC refrigerants under the AIM Act. One unexpected significant component of this ruling is a ban on disposable refrigerant cylinders beginning in 2025.

AHRI Guideline M 2020, Unique Fittings and Service Ports for Flammable Refrigerant Use specifies that service connections for systems with A2L refrigerant should be exactly the same as those used on systems with A1 refrigerant. The connection on A2L refrigerant cylinders is described as a CGA 164 connection. The CGA 164 connection is described in the CGA Standard V-1 2019 as a 1/4 inch flare with left hand threads.

CGA Standard V-1 2019 Standard for Compressed Gas Cylinder Valve Outlet and Inlet Connections introduces the CGA 164 connection. It is designed specifically for A2L refrigerant cylinders. The standard describes the CGA 14 connection as a 1/4 inch flare with left hand threads. While the CGA 164 connection is first introduced in the 2019 edition, the latest edition of the CGA V-1standard is now 2021.

UL Standard 207 Standard for Safety Refrigerant-Containing Components and Accessories, Nonelectrical covers nonelectrical, refrigerant-containing components and accessories in accordance with ASHRAE Standard 15. This standard is specifically referenced by ASHRAE Standard 15.2 when describing fittings, valves, and mechanical joints.

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