Quick answer
A1, A2L and A3 are refrigerant safety classes. They come from ISO 817 and from ANSI/ASHRAE Standard 34, not from Union law, and they are not the same thing as the hazard classification that appears on the cylinder label under Regulation (EC) No 1272/2008 (CLP).
The class has two parts. The letter is toxicity: A for lower toxicity, B for higher toxicity. The figure is flammability: 1, 2L, 2 or 3, from practically non-flammable to extremely flammable. A2L therefore means lower toxicity and mild flammability; A3 means lower toxicity and high flammability.
Regulation (EU) 2024/573 does not assign safety classes. It does three things that depend on them: it requires certification programmes to cover the safe handling of flammable, toxic and high-pressure gases (Article 10(5), point (e)); it allows a higher GWP where the safety requirements at the site rule out the lower one (Annex IV, point 8); and it requires that fact to be written on the label (Article 12(15)).
It does not reproduce or summarise ISO 817, EN 378 or IEC 60335. Those standards are not freely readable and cannot be verified from a primary source. You will not find charge limits, room-size formulas, occupancy limits or ventilation rates here. Those come from the applicable standard, from the equipment manufacturer's instructions and from the safety data sheet of the product you actually have.
The two axes of the scheme
Manufacturer technical documentation describes the scheme the same way. Toxicity is divided into two groups: A for lower-toxicity refrigerants and B for higher-toxicity ones. Higher-toxicity refrigerants such as R-123 and R-717 (ammonia) are typically limited to indirect systems, for example chillers in machinery rooms.
Flammability is divided into four classes, defined by a flame-propagation test and by three parameters: the lower flammability limit, the heat of combustion and the burning velocity.
- Class 1 — no flame propagation in the test at 60 °C and 101,3 kPa. Described as practically non-flammable under most use conditions.
- Class 2L — flame propagation occurs, the lower flammability limit is above 0,10 kg/m3, the heat of combustion is below 19 000 kJ/kg, and the burning velocity is 10 cm/s or less.
- Class 2 — the same first three conditions, without the burning-velocity limit.
- Class 3 — flame propagation occurs and either the lower flammability limit is 0,10 kg/m3 or below, or the heat of combustion is 19 000 kJ/kg or more.
Supplier documentation says so explicitly: a refrigerant with safety class 1, which shows no flame propagation, may still decompose when exposed to a flame. That is why open flames in the work area are a problem with every class, not only with the flammable ones.
The 2L class exists because the older three-class scale put very different substances in the same box. A mildly flammable refrigerant with a burning velocity below 10 cm/s does not behave like propane. The 2L class is recognised in ISO 5149 and in EN 378, which also set out the precautions that go with it.
Where the refrigerants you meet fall
The table below lists only classes confirmed in the manufacturer documentation consulted for this page. It is not a complete list and it does not replace the document that comes with your product.
| Refrigerant | Safety class | Where it was verified |
|---|---|---|
| R-410A | A1 | Chemours technical bulletin for R-407C and R-410A |
| R-407C | A1 | The same technical bulletin |
| R-22 | Class 1 | Chemours bulletin on the safety of Opteon XL refrigerants |
| R-32 | A2L | Chemours bulletin on A2L refrigerants |
| R-1234yf | A2L | Both Chemours bulletins |
| R-454B | A2L | Opteon XL property table |
| R-454C | A2L | Opteon XL property table |
| R-152a | Class 2 | Chemours bulletin on the safety of Opteon XL refrigerants |
| R-290 (propane) | A3 | Chemours bulletin on A2L refrigerants |
| R-717 (ammonia) | Higher toxicity (group B) | Chemours bulletin on A2L refrigerants, as a group B example |
Two points that matter at goods-in. First, two blends with similar names can sit in different classes, because the ratio of the components differs. Second, you cannot infer the class from the working pressure or from the chemical family. Check the product document, not your memory.
If you are choosing between an A1 and an A2L for a specific system, see also R-32 or R-410A and low-GWP refrigerants on site.
The safety class is not the CLP classification
What you find on the cylinder is a hazard label drawn up under Regulation (EC) No 1272/2008. It does not say A1, A2L or A3. CLP uses different scales:
- Flammable gases — category 1A, 1B or 2 (Annex I, section 2.2.2.1).
- Gases under pressure — compressed gas, liquefied gas, refrigerated liquefied gas or dissolved gas (Annex I, section 2.5.2.1). A gas counts as under pressure when it is contained in a receptacle at 200 kPa gauge or more at 20 °C, or when it is liquefied, or liquefied and refrigerated (section 2.5.1.1).
The three safety data sheets consulted for this page show the difference:
| Product (sheet consulted) | CLP classification | Pictograms | Signal word |
|---|---|---|---|
| Propane (Air Liquide sheet, version 6.0) | Flammable gases category 1A, H220; gases under pressure, liquefied gas, H280 | GHS02, GHS04 | Danger |
| R-1234yf (Messer sheet, version 1C) | Flammable gases category 1B, H221; gases under pressure, liquefied gas, H280 | GHS02, GHS04 | Danger |
| R-410A (Messer sheet, version 2D) | Gases under pressure, liquefied gas, H280 | GHS04 | Warning |
You can see at once that an A2L refrigerant is, in CLP language, a flammable gas, while an A1 refrigerant normally carries only the gas-under-pressure hazard. You can also see something more subtle: the R-410A sheet declares a 50/50 blend of R-125 and R-32, and the R-32 component is itself classified as a flammable gas, category 1B, H221. The blend is not flammable as placed on the market, but it contains a flammable component, and that only shows up in section 3 of the sheet.
Implementing Regulation (EU) 2024/2174 provides in Article 1(6) that, where a container also has to be labelled under CLP, the information required by Article 12 of Regulation (EU) 2024/573 is to be given in the supplemental information section of the CLP label referred to in Article 25 of Regulation (EC) No 1272/2008. One label, two regimes.
Two CLP rules are worth remembering when you check paperwork. Article 18(1) requires the term used to identify the product on the label to be the same as the one used in the safety data sheet. Article 25(3) forbids supplemental information that contradicts or casts doubt on the mandatory label elements. If you hit that kind of discrepancy, see what to do when the cylinder label does not match the safety data sheet.
What actually changes on the job
What follows are general principles. The instructions that bind you come from the safety data sheet for the product (sections 2, 5, 6, 7 and 8), from the equipment manufacturer's instructions, and from the standard applicable to the installation. The format of the sheet is set by Regulation (EU) 2020/878, so the information sits in the same place whoever the supplier is.
- Oxygen displacement applies to every class. An A1 refrigerant is not flammable, but in a confined space it is still an asphyxiant. The safety class does not change that risk.
- With 2L, 2 and 3 you add the flammable-mixture question. The precautionary statements in the sheet, of the kind "keep away from heat, hot surfaces, sparks, open flames and other ignition sources", become instructions for organising the work area, not paperwork.
- Recovery and service equipment has to suit the refrigerant. For flammable refrigerants the vacuum pump, hoses, valves and recovery cylinder must be suitable, and it is the equipment manufacturer who states that, not the F-gas Regulation.
- Cylinder connections differ. Implementing Regulation (EU) 2024/2215 requires, in Annex I, item 12.01, knowledge of the special requirements for flammable refrigerants in equipment, systems and refrigerant cylinders, including the special requirements on bottle connections.
- Storage changes. The conditions in section 7.2 of the sheet are different for an A3 than for an A1. See also storing cylinders.
Above all of this sits the general duty in Article 4(3) and (4) of Regulation (EU) 2024/573: whoever is in possession of the equipment, including during its transport or storage, shall take all necessary precautions to prevent the unintentional release of the gases.
Read the sheet for the exact product you have
Not for a refrigerant with a similar name. Section 2 gives you the CLP classification and the hazard statements, section 3 the composition, section 7 handling and storage.
Establish the safety class from the supplier documentation
The class A1, A2L, A2 or A3 comes from ISO 817 and ASHRAE 34 and appears in the product data sheet or technical bulletin. If you cannot find it, ask the supplier for it in writing.
Check which refrigerant the equipment was designed for
A system designed for an A1 does not become suitable for an A2L because the pressures look similar. See the difference between a straight replacement and a retrofit in the drop-in or retrofit guide.
Prepare the work area before you open the circuit
Remove ignition sources, secure ventilation, and assess whether the space is enclosed or partly enclosed. With classes 2L, 2 and 3, brazing, welding and electrical work are planned, not improvised.
Use recovery equipment suited to the class
Recovery is required by Article 8 of Regulation (EU) 2024/573 and is carried out by certified persons. The equipment must be declared by its manufacturer as suitable for that refrigerant.
Record what you used and how much
For equipment subject to leak checks, Article 7(1) of Regulation (EU) 2024/573 requires the quantity and type of gas added to be recorded. See the guide on F-gas equipment records.
Certification covers the alternatives too, not just the fluorinated gases
This is the point where safety classes enter the regulation explicitly. Article 10(1) of Regulation (EU) 2024/573 says that natural persons shall be certified to carry out the listed activities involving fluorinated greenhouse gases "or involving relevant alternatives to fluorinated greenhouse gases, including natural refrigerants, where relevant".
The certification programmes and the training on practical skills and theoretical knowledge shall cover, among other things, the "safe handling of equipment containing flammable or toxic gases or operating under high-pressure or involving other relevant risks".
Implementing Regulation (EU) 2024/2215 carries that requirement through. Article 2(1), points (b) and (c), brings within scope the installation, repair, maintenance, servicing and decommissioning of the equipment listed in Article 1 containing fluorinated greenhouse gases or the alternative substances ammonia (NH3), carbon dioxide (CO2) or hydrocarbons. Article 2(2) extends the same thing to legal persons carrying out that work for third parties.
The content of the examination is in Annex I:
- Item 1.08 — knowledge about flammability, flame propagation, charge size restrictions and occupancy limits for HFCs, H(C)FOs and hydrocarbons. Examined for every certificate type.
- Item 11.03 — knowledge of the relevant safety regulations and standards for the use, storage and transport of flammable or toxic refrigerants, or refrigerants requiring a higher operating pressure, and understanding of the site-specific conditions under which equipment that does not meet the requirements of Annex IV to Regulation (EU) 2024/573 may be used for safety reasons.
- Item 12.01 — the labelling requirements and the special requirements for flammable refrigerants in equipment, systems and refrigerant cylinders, including bottle connections.
Under Annex I, point (2), knowledge group 12 (hydrocarbons) is examined for certificates A1 and A2, group 13 for certificate B (CO2) and group 14 for certificate C (NH3). In short: an A1 or A2 certificate covers hydrocarbons as well, not only fluorinated gases. The detail by category is in the guide on F-gas certificate categories.
The safety derogation in Annex IV and the label that goes with it
The regulation accepts that at some sites the safety requirements rule out the lower-GWP refrigerant. Article 3, point (42), defines "safety requirements" as requirements on the safety of using fluorinated greenhouse gases and natural refrigerants, or products and equipment containing or relying on them, prohibiting the use of certain fluorinated greenhouse gases or their alternatives, including when contained in a product or in equipment at a specific place of intended utilisation, because of site and application specificities, set out in Union or national law or in a non-legally binding act containing technical documentation or standards that have to be applied to ensure safety at that location.
The practical consequence shows up in Annex IV:
- Point 8(b), (d) and (e) — for monobloc and other self-contained air-conditioning equipment and heat pumps, the prohibition targets gases with a GWP of 150 or more, "except if required to meet safety requirements". And where the safety requirements at the site of operation would not allow using a gas with a GWP of less than 150, the limit becomes 750.
- Point 8(c) — from 1 January 2032 the prohibition targets fluorinated greenhouse gases as such; where safety requirements at the site do not allow using alternatives to fluorinated greenhouse gases, the limit is again 750.
- Point 9(b) to (f) — for split systems the exception is stated plainly, "except if required to meet safety requirements at the site of operation", with no numeric fallback value.
Article 12(15) requires the product or equipment in those cases to be labelled with an indication that it shall be used only where required by the safety requirements or national safety standards, and those requirements or standards have to be specified on the label. Implementing Regulation (EU) 2024/2174 sets the exact wording in Article 1(12)(a) for the equipment in Annex IV, points 8(b) to (e) and 9(b) to (f), with a reference to the applicable safety requirement or space left on the label for the supplier, installer or operator to insert it before the equipment is put into operation.
The practical reading: the 750 limit is not a general escape hatch to a higher-GWP gas. It applies only where the safety requirements at that particular site rule out the lower-GWP option, and the reason has to stay visible on the label. The full ban timetable is in the guide on the F-gas ban timetable.
Checklist
- You have the safety class in writing, for the exact productFrom the supplier's product data sheet or technical bulletin. Not inferred from the chemical family.
- You have the safety data sheet in the working languageThe format is the one set by Regulation (EU) 2020/878; sections 2, 3, 7 and 8 are the ones that change between classes.
- You checked the CLP classification, not just the safety classFlammable gas category 1A, 1B or 2, and gas under pressure. Those are different scales from A1, A2L, A3.
- The working equipment is declared suitable for that refrigerantVacuum pump, hoses, detectors and recovery cylinder. The declaration comes from the equipment manufacturer.
- The work area is prepared before the circuit is openedIgnition sources removed, ventilation secured, the space assessed. Mandatory practice with classes 2L, 2 and 3.
- The certificate of the person doing the work covers the substance usedArticle 10(1) of Regulation (EU) 2024/573 and Article 2 of Regulation (EU) 2024/2215, including for NH3, CO2 and hydrocarbons.
- If you rely on the safety derogation, the requirement is written on the labelArticle 12(15) and Article 1(12)(a) of Regulation (EU) 2024/2174.
- Recovery is planned before the interventionArticle 8 of Regulation (EU) 2024/573. See the guide on the refrigerant recovery obligation.
- You recorded the quantity and type of gas addedArticle 7(1) for equipment subject to leak checks.
Frequently asked questions
Does Regulation (EU) 2024/573 use the term A2L?
No. The regulation does not assign safety classes and does not use the notations A1, A2L or A3. The classes come from ISO 817 and ANSI/ASHRAE 34. The regulation reaches safety through other wording: "flammable or toxic gases or operating under high-pressure" in Article 10(5), point (e), and "safety requirements" in Article 3, point (42), and throughout Annex IV.
Why does the cylinder label not say A2L?
Because the hazard label follows Regulation (EC) No 1272/2008, which uses different categories: flammable gases 1A, 1B or 2, and gases under pressure. The fluorinated-gas information is added in the supplemental information section of the same label, under Article 1(6) of Implementing Regulation (EU) 2024/2174. The ISO 817 safety class appears in the product technical documentation, not as a mandatory label element.
Can a non-flammable blend contain a flammable component?
Yes, and the sheet shows it. The sheet consulted for R-410A declares a 50/50 blend of R-125 and R-32, classified as a product only as a liquefied gas under pressure, H280, while the R-32 component is separately classified as a flammable gas, category 1B, H221. Composition is read in section 3 of the sheet.
What exactly separates 2L from 2?
Both classes require flame propagation in the test, a lower flammability limit above 0,10 kg/m3 and a heat of combustion below 19 000 kJ/kg. Class 2L adds one condition: a burning velocity of 10 cm/s or less. That is the difference that justified separating 2L and having it recognised in ISO 5149 and EN 378.
Does my F-gas certificate let me work with propane?
It depends on the certificate type. Under Annex I, point (2), of Implementing Regulation (EU) 2024/2215, knowledge group 12, on the installation and good servicing practice for equipment relying on hydrocarbons, is examined for certificates A1 and A2. Group 13 is examined for certificate B (CO2) and group 14 for certificate C (NH3). Check which type you hold and which activities it covers.
Can I use a gas with a GWP of 750 by invoking safety?
Only in the situations described in Annex IV, point 8, and only where the safety requirements at the site of operation would not allow a gas with a GWP below 150. The reason has to be a safety requirement within the meaning of Article 3, point (42), and the specific requirement has to be stated on the label under Article 12(15). For the split systems in Annex IV, point 9, there is no 750 fallback: the exception there is the safety one, with no alternative numeric value.
Official sources
The articles and annexes cited were read directly in the Official Journal text. The safety classes and their numeric criteria come from manufacturer technical documentation, and the CLP examples from real safety data sheets, consulted in the form published by the supplier.
Currency of this page and limits of responsibility
This page explains a classification scheme and the points where the F-gas Regulation relies on it. It does not replace the standard applicable to the installation, the equipment manufacturer's instructions or the product safety data sheet. It contains no charge limits, no occupancy limits, no ventilation formulas and no numeric transport thresholds.
General information prepared by EgoLog from Union legislation and manufacturer technical documentation. It is not legal advice.
Work on systems with flammable or toxic refrigerants, or at high pressure, is carried out by certified persons with suitable equipment. Confirm the applicable requirements with your supplier, with the equipment manufacturer and with your national competent authority.