Why are some hydrofluoroolefin refrigerants classified as a2l?
Why are some of the hydrofluoroolefins classified as A2L? They are less flammable than hydrocarbon refrigerants, but most are still mildly flammable.
HFO refrigerants generally fall in the category of A2L refrigerants because they contain fluorine. Fluorine makes HFO refrigerants less flammable than hydrocarbon refrigerants, which are highly flammable.
R-1234ze is an HFO and is classified as A2L, but, as previously noted, it is actually non-flammable at temperatures below 300C. R-1234yf is a closer match to the performance of R-134a, which makes it suitable for use in chillers where the system is designed to use a lower flammability refrigerant.
The notable difference between A2 and A2L refrigerants is the burning velocity, which is < 10 cm/s for A2L while it is > 10 cm/s for A2. This difference allows a higher charge of A2L refrigerants because the risks are considerably reduced (10 cm/s).
The hydrofluoroolefins are the synthetic refrigerants having zero ODP, low GWP and extremely short atmospheric lifetime. The fluorinated isomers also can be identified as for example HFO-1234ye, HFO-1234yf. When a carbon-carbon double bond exist is stereoisomers may exist.
While A2Ls are mildly flammable, they are less flammable than Class 3 refrigerants and are safe when handled properly. Like all refrigerants, specific codes and standards apply to A2Ls. A2L refrigerants, or A2Ls, are used in refrigeration systems around the world, making sure that cold items stay cold.
This is the substantial difference between a refrigerant in class A3 and a refrigerant in class A2L: the sufficient refrigerant quantity in air to generate a combustion is ≤ a 3% in case of an A3 and higher than this value in case of A2L.
What's in Your State? Connecticut, Florida, North Carolina, Ohio, Oregon, South Carolina, Utah, Washington, and West Virginia have already updated their state building codes to allow for the use of A2L refrigerants in air conditioners.
The A2L subgroup, as categorized by ASHRAE Standard 34, are a class of refrigerants that have lower toxicity and flammability (flame propagation speed is less than 10 cm/s) compared to other classifications — A = non-toxic, 2 = flammable, L = low burning velocity — making it the second-safest refrigerant category.
Class I includes the fully halogenated CFCs, halons, and the ODSs that are the most threatening to the ozone layer. Class II compounds are those substances that are known or reasonably anticipated to have harmful effects on the stratospheric ozone layer. Class II substances are all hydrochlorofluorocarbons (HCFC).
Is R-410A a A2L refrigerant?
A2Ls are seen as the replacement for the popular R410-A refrigerant, as passed by Congress' American Innovation and Manufacturing (AIM) Act. In line with the AIM Act, the use of R410-a refrigerant will be phased out in new HVAC systems in 2023 in favor of A2L refrigerants.
R1234yf is classified as an A2L mildly flammable refrigerant, and requires the use of equipment designed for use with such a refrigerant.
Classified as mildly flammable (A2L), R454B allows for a much higher charge size than other flammable refrigerants and can be safely used by following the applicable codes and standards.
Hydrofluoroolefin (HFO) refrigerants are unsaturated organic compounds composed of carbon, hydrogen and fluorine.
Many HFOs have the proper freezing and boiling points to be useful for refrigeration at common temperatures. They have also been adopted as blowing agents, i.e. in production of insulation foams, food industry, construction materials, and others.
HFOs Are Replacing HFCs (For the Better!)
HFO stands for hydrofluoroolefin. The chemical is also made of hydrogen, fluorine, and carbon. However, unlike HFCs, HFOs have zero ODP (Ozone Depletion Potential) and low GWP, making them a more environmentally-friendly option than HFCs.
Certification. The Low GWP Refrigerant Safety - A2L Refrigerants examination validates that a person possesses the knowledge to safely work with low GWP refrigerants and helps reduce liability. The 50-question, closed-book exam covers the following competencies: General Flammable Refrigerant Safety Knowledge.
In terms of an A2Ls flammability they typically require: Greater than 0.3kg/m³ concentration in air to burn. A heat of combustion of <19,000kJ/kg. A burning velocity of <10cm/s.
Hydrocarbons such as R290 are A3 refrigerants; The refrigerants listed in the table above (R32 etc.) are classified A2L.
Please remember that using the wrong type of refrigerant for your system can create a hazard or cause serious damage so it is very important to get it right.
What are the three classes of refrigerant?
In sum, refrigerants in class “3” are highly flammable; refrigerants in class “2” are considered less flammable; and those in class “2L” are mildly flammable. These classifications are used in the guidelines for determining how much refrigerant can be used in an occupied space.
| Size | Height Range | Weight Range |
|---|---|---|
| A2L | 5ft 11” – 6ft 2” | 72 – 82kg |
| A3 | 6ft 1” – 6ft 3 | 82 – 95kg |
| A3L | 6ft 3” – 6ft 4” | 82 – 95kg |
| A4 | 6ft 1” – 6ft 4” | 95 – 120kg |
However, there isn't just one type of refrigerant, which makes it easy to get them confused. There are actually three different types, and using the wrong one can damage your air conditioner because they're not interchangeable.
They are divided into two groups: HC refrigerants and inorganic refrigerants. The following are natural refrigerants: 1) various hydrocarbons (HC), 2) carbon dioxide (R744), 3) ammonia (R717), 4) water (R718) and 5) air.
The Occupational Safety and Health Administration (OSHA) requires that if flammable refrigerant cylinders are to be stored in an enclosure, the enclosure be secure and ventilated. They cannot be enclosed in confined spaces, containers, or lockers.
The A2L subgroup, as categorized by ASHRAE Standard 34, are a class of refrigerants that have lower toxicity and flammability (flame propagation speed is less than 10 cm/s) compared to other classifications — A = non-toxic, 2 = flammable, L = low burning velocity — making it the second-safest refrigerant category.
ASHRAE class A2: 10–35°C (50–95°F); when the altitude exceeds 900 m (2953 ft), the maximum ambient temperature value decreases by 1°C (1.8°F) with every 300 m (984 ft) of altitude increase.
A1 equipment operates from 15 to 32 degrees Celsius at 20% to 80% relative humidity. A2 equipment operates from 10 to 35 degrees Celsius at 20% to 80% relative humidity. A3 equipment operates from 5 to 40 degrees Celsius at 8% to 85% relative humidity.
“Class II” ozone-depleting substances ( ODS. ODS include chlorofluorocarbons (CFCs), hydrochlorofluorocarbons (HCFCs), halons, methyl bromide, carbon tetrachloride, hydrobromofluorocarbons, chlorobromomethane, and methyl chloroform.
Group 2: low flammability index.
Those whose lower limit or whose minimum concentration of refrigerant can spread the flame in the homogeneous mixture with air at a percentage equal to or greater than 3.5% by volume (V/V).
What is the difference between primary and secondary refrigerant?
Refrigeration & Equipment Engineering (1+1)
The primary refrigerant which directly take part in the refrigeration system. Where as the refrigerant which are first cooled by primary refrigerants and then used for cooling purpose is called secondary refrigerants.
R410A refrigerant is a type of hydrofluorocarbon (HFC) refrigerant used in air conditioning systems and heat pumps. It is also known as Puron or Genetron R410A.
R 410A and R 22 both in Class 1 are considered virtually non-combustible.
ASHRAE Standard 15.2P
Currently the widely used R410A in packaged and split systems is classified as an A1 (Low Toxicity & No Flammability) refrigerant.
The auto industry has transitioned some U.S. models to R-1234yf, although it's not required by current U.S. law. The reason the auto industry is transitioning its U.S. models is to achieve commonality with European models, and to gain Corporate Average Fuel Economy (CAFE) “credits” from the EPA.
We have received some questions about putting R-134a into HFO-1234yf system and here's why you should not do that from EPA.
The R-1234yf is much more reactive than R-134a. On the positive side, this higher reactivity is why R-1234yf is so much more friendly to the environment. It tends to react with other gases in the atmosphere and break down within a couple of weeks, as compared to R-134a, which remains stable for over a decade.
In summary, A2L refrigerants are not toxic but mildly flammable refrigerants, and most HFOs as well as R-32 belong to this category. The definition alone suggests a pro and a con of this class of refrigerant: they are less flammable than A2 and A3 refrigerants but more flammable than A1 refrigerants.
It is important to note that as a mildly flammable refrigerant, R-454B cannot be retrofitted into existing R-410A or R-22 systems.
In general, these results show that R452B and R454B are good replacement candidates for R410A for heat pump using tube-fin heat exchangers and microchannel heat exchangers.
Why are some HFOs classified as A2L?
HFO refrigerants generally fall in the category of A2L refrigerants because they contain fluorine. Fluorine makes HFO refrigerants less flammable than hydrocarbon refrigerants, which are highly flammable.
Why are some of the hydrofluoroolefins classified as A2L? They are less flammable than hydrocarbon refrigerants, but most are still mildly flammable.
HFO-1234yf is a new class of refrigerants known as hydrofluoroolefins. These refrigerants are similar to HFC refrigerants except that they have a much much lower Global Warming Potential number.
The hydrofluoroolefins are the synthetic refrigerants having zero ODP, low GWP and extremely short atmospheric lifetime. The fluorinated isomers also can be identified as for example HFO-1234ye, HFO-1234yf. When a carbon-carbon double bond exist is stereoisomers may exist.
Hydrofluorocarbons (HFCs) contain Hydrogen, Fluorine, and Carbon (no chlorine). Hydrochlorofluorocarbons (HCFCs) contain Hydrogen, Chlorine, Fluorine, and Carbon atoms.
A2L refers to a class of refrigerants that possess lower flammability and toxicity levels compared to other classifications. The name is derived from the ISO 817 standard, “Refrigerants —Designation and safety classification”: A = Non-toxic. 2 = Flammable. L = Low burning velocity.
Certification. The Low GWP Refrigerant Safety - A2L Refrigerants examination validates that a person possesses the knowledge to safely work with low GWP refrigerants and helps reduce liability. The 50-question, closed-book exam covers the following competencies: General Flammable Refrigerant Safety Knowledge.
Hydrocarbons such as R290 are A3 refrigerants; The refrigerants listed in the table above (R32 etc.) are classified A2L.
They are divided into two groups: HC refrigerants and inorganic refrigerants. The following are natural refrigerants: 1) various hydrocarbons (HC), 2) carbon dioxide (R744), 3) ammonia (R717), 4) water (R718) and 5) air.
Class 2 is for refrigerants that, when tested, exhibit flame propagation at 140°F (60°C) and 14.7 psia (101.3 kPa), have a heat of combustion less than 19,000 kJ/kg (8,174 British thermal units BTU/lb), and have a lower flammability limit (LFL) greater than 0.10 kg/m3.
What is upon completion of an A2L system installation?
Upon completion of an A2L system installation: a permanent label must be placed on the system to show required service dates. the fire suppression system must be tested to ensure proper operation. the manufacturer's literature must be kept on file by the contractor performing the installation.
What is the new HVAC refrigerant type in 2023? R-454b is a more environmentally friendly alternative to R-410a. The industry change will create much lower global warming potential.
Ammonia refrigerant is highly toxic and flammable.
The aqueous form of ammonia is known as ammonium hydroxide. This compound has a pungent smell. It is a dangerous and caustic compound. Hence, ammonia refrigerant is highly toxic and flammable.
The most common toxic refrigerant is ammonia, and you would generally only find it in old appliances or large industrial applications. Propane (R290) is a flammable refrigerant and is becoming quite popular in small self-contained refrigeration units like vending machines and reach-in coolers.
Class A denotes refrigerants of lower toxicity, and class B denotes refrigerants of higher toxicity.
Replacement refrigerants
Alternative substances for R290 is R600a and R1270.
R290 is Class A3 refrigerant by ASHRAE's Standard 34 refrigerant safety group. It is a highly flammable compressed gas and should only be handled by experienced and properly instructed persons. R290 is an extremely pure propane which is used in low temperature refrigeration applications.
According to this classification, the SDS and labels are required to provide specific information under the GHS such as the Signal Word: DANGER and Hazard Statement: Extremely Flammable (code:H220). This must be shown on the product SDS and package labels.