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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.  

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.

Stay Safe in the Heat

When you think about the dangers of working on air conditioning equipment, you probably think about working with electricity, refrigerant, and torches. We often overlook a more obvious danger: the weather. The reason we have a job is because it is either hot or cold. It seems like every year there is tragic news involving the death of an HVAC worker found unconscious or dead in an attic due to heat stroke. These tragic deaths are totally preventable and unnecessary.

To avoid becoming a victim of heat stroke you must monitor your body’s reaction to the heat. When you are hot, sweating is good. The evaporation of sweat is your last line of defense against overheating. Sometimes sweating just isn’t enough to counteract the effects of work and hot, humid conditions. If you are sweating profusely and experiencing a rapid pulse, muscle cramps, and dizziness, you are experiencing heat exhaustion. To avoid becoming a victim of heat stroke you need to get out of the heat, hydrate, and cool off. If it is hot and you are NOT sweating, you are past heat exhaustion and entering into heat stroke. This is very dangerous, you can pass out from heat stroke. Symptoms include dry, hot skin (90+); rapid pulse (130+), headache, dizziness, and confusion. If you have these symptoms, you may be the victim of heat stroke – which is life threatening. You should get out of the heat, hydrate, and call 911. Don’t ignore what your body is telling you. If you start feeling bad while working in the heat – get to a cool place and hydrate.

The locations where HVAC techs are exposed to the most extreme heat are attics and commercial rooftops. Jobs in these locations should be scheduled for early morning to avoid the worst heat. Air movement can help in attics. On rooftops you can shield yourself from the sun using canopies or umbrellas. Keeping hydrated is critical. You should have plenty of water and sports drinks available all the time. You should avoid alcohol or caffeinated sodas because they are diuretics and can actually dehydrate you. Sorry, but you cannot keep hydrated by drinking beer.

Tools that can help you stay safe include heat stress meters and wearable health monitoring devices. Heat stress meters can help determine the effective heat index of the work area. They measure the combined effect of temperature, humidity, and mean radiant temperature to determine the effective temperature in an area where you are working. They can include an alarm that warns you if the heat index will exceed a safe level. Wearable devices can measure your body’s reaction to the work environment. While a heat stress meter measures the area, the wearable monitor measures you. One, the CORE, measures your body temperature and heart rate. Using this device you can determine how your body is handling the heat and take action when signs of heat exhaustion are indicated. Here are links for these two devices.

Heat Stress WBGT Meter-HT30 (trutechtools.com)

CORE Body Temperature Sensor

I highly recommend that you do some research to better understand how to stay safe. To that end I am including several links

Heat exhaustion – Symptoms and causes – Mayo Clinic

Heatstroke – Symptoms and causes – Mayo Clinic

Heat Stress Related Illness | NIOSH | CDC

OSHA Guidelines to Prevent Heat Illness | TFT Pneumatic (tft-pneumatic.com)

Beat the Heat: Identifying and Preventing Heat Stress | (3m.com)

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.

Teach the Process , part 2

In an earlier post entitled “Teach the Process”, I made the observation that many students across all levels of education fail to gain a thorough understanding of the subject matter being taught. I named standardized, multiple-choice tests as the primary culprit. It is not that these assessments don’t have value. It is that they should just be a part of the learning tapestry, not the overarching goal. Nobody’s educational goal should be to pass a multiple choice test. The goal should be to understand the subject matter. Really, this gets back to how we learn. I found a quote by Ruth and Art Winter describing what learning is. According to the Winters, “Learning is the ability to make sense out of something you observe based on your past experience and being able to take that observation and associate it with meaning.” Not just storing away facts, but organizing and associating these facts in our minds so that we can use previous experiences to understand new ones. In our brains, we make new connections between neurons when we learn new things. The more connections you have to any given “fact”, the better the likelihood you will be able to recall it and use it for meaningful association. It is a teacher’s job to help students make these connections. We need to show how the data are related and engage the student’s interest. To achieve good results, teachers need use a variety of techniques beside the standard, and somewhat boring lecture.

Visual aids help catch student attention and can illustrate things that are awkward to describe in words. For example, try writing out the detail for connecting a standard gauge manifold. Each valve on the system needs a name, each valve on the manifold needs a name, you have to describe which way valves are being turned or positioned. It gets complicated and is very confusing to read. Now replace that with a video showing the connections. It is much easier to understand and a whole lot less confusing.

Manipulatives are items that students hold in their hands that help them learn. This is actually a term used for kindergarten classes. I have found that what works with kindergarteners also works with adults. So if you are talking about electric meters, each student should have a meter in their hand during the lecture. Then design the lesson around the fact that the students can actually handle and operate the meters during the lesson.

Analogies are great for helping students understand concepts. Dave Boyd of Appion used to compare pulling a vacuum through a 1/4” charging manifold  to the traffic jams created by merging two lanes of traffic into one. Everyone has experienced that and can relate that experience to the gas slowing down as it travels through the manifold.

Scaffolding is a way to help students reach a higher level of understanding by building information one piece at a time. It can be more successful to describe a complicated procedure in small steps. One way we do this at Athens Tech is to wire a project resembling a packaged air conditioner one circuit at a time. Students often are glassy eyed when they see the whole thing, already done. But each circuit is pretty simple. So doing one at a time gets the job done.

All of these techniques involve exploring relationships. The more ways you can describe something and how it relates to other things, the more brain connections you build. The more connections you build, the better your chance of using that information. I will be speaking at the upcoming National HVACR Education Conference by HVAC Excellence in Las Vegas on Tuesday, March 22. Come see me and we can brainstorm about more ways to make connections.

Duck Tape

Like many others, I have assumed for years that the original and proper spelling for the ubiquitous gray cloth tape is duct tape, as in taping duct seams. I was wrong. I just recently learned some of the history of the original invention of Duck Tape by reading about it on a Facebook post by George Lanthier. If you work in oil or gas heat in the northeast, you probably have at least heard of George.  I know he knows what he is talking about, but we are talking about a Facebook post, so I did a little more research. According to Educationalnow.com, the word duck comes from the Dutch word doek, which means linen canvas. According to thoughtco.com, soldiers called it “Duck Tape” because of the way it repelled water. Perhaps both are true. But that is not really the interesting part of the story.

A mom named Vesta Stoudt came up with the original idea for Duck Tape while working in a factory packing ammo boxes. Before the development of Duck Tape, cartridges were packed in heavy cardboard boxes that were taped and dipped in wax to make them waterproof. The box flaps were sealed with thin paper tape, and a tab of tape was left loose so that it could be pulled to release the waterproof wax coating and open the box. The problem was that the thin paper tape wasn’t strong enough, and the tabs frequently tore off when soldiers pulled on them to open the ammo boxes, leaving them frantically scrambling to claw the boxes open while under enemy fire. Vesta developed a prototype cloth tape to solve this problem. She had a personal reason for her concern about the effectiveness of the ammo box sealing method, she had two sons in the Navy.  Unable to convince her supervisors of the merits of her idea, she wrote president Roosevelt. President Roosevelt and his military advisors liked Vesta Stoudt’s idea, and they asked the Industrial Tape Corporation, a division of Johnson & Johnson, to develop and manufacture a cloth-backed, water-resistant tape with a strong adhesive. Duck tape was made with a layer of cotton canvas (doek) coated in waterproof polyethylene, and a layer of strong rubber-based adhesive. Soldiers returning from the war found all sorts of uses for Duck Tape and its usefulness made it popular. Duck tape was not used for duct work until after World War II. Unfortuneately, the original style Duck tape is not actually recommended for use on duct work. It tends to dry up and become brittle. However, there are many other practical uses for general purpose Duck Tape.  Manco, now part of ShurTech Brands,  trademarked the name “Duck Tape” in 1980. Today, any tape actually named “Duck Tape” is from ShurTech. Now there actually is tape designed specifically for sealing ductwork, and it is referred to as “duct tape.”  Tape used with ductwork should have a UL 181 rating. The next time you hear someone mention “Duck Tape,” just realize they are being historically correct.

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