The F-gas Regulation (EU) 2024/573 progressively bans refrigerants with a high global warming potential (high GWP). Alternatives with a very low GWP are often Class A3 flammable gases, such as propane (R-290). However, in many locations these flammable gases cannot be used safely.
For these specific cases, the Regulation provides for an important safety exemption: this allows systems using safer refrigerants (belonging to classes A1 or A2L) to be legally installed, even if their GWP is theoretically too high, provided that local safety regulations prohibit or restrict the use of highly flammable gases.
What are classes A1, A2L and A3?
Refrigerants are classified according to their flammability (all those mentioned have low toxicity, indicated by the letter ‘A’):
- Class A1: Non-flammable. This is the safest class in terms of fire risk (e.g. R-744, R-513A, R-134a, R-410A). No risk of ignition.
- Class A2L: Low flammability. These gases are difficult to ignite and burn slowly (e.g. R-32, R-1234yf, R-1234ze, R-454B) and have a low calorific value. The risk is very low and easily manageable.
- Class A3: Highly flammable, explosive. Dangerous even in the event of a small leak (e.g. R-290, R-600a). The risk of fire and explosion is high.
When it is possible (and advisable) to install A1 or A2L instead of A3
The safety exemption is applied on a case-by-case basis, carefully assessing the combination of {system + refrigerant + installation site}. Here are the typical cases in which an A3 gas is not permitted and A1 or A2L are chosen:
Tall buildings (skyscrapers / high-rise buildings): Above 28 metres (offices, hotels, hospitals) or 50 metres (residential), many national standards and fire safety codes prohibit flammable refrigerants. → Use A1 or A2L.
- Crowded public places: Shopping centres, schools, hospitals and cinemas. → Opt for A1 or A2L.
- Enclosed, underground or poorly ventilated spaces: Places where any gas leak would accumulate, creating a risk of explosion. → Use A1 (or A2L with the necessary precautions).
- Critical infrastructure: Stations, airports, data centres and tunnels, which are often subject to specific technical regulations. → Choose A1 or A2L.
- Gas charge too high for the room: Standards EN 378 and IEC 60335-2-40 set the maximum quantity of flammable refrigerant based on the room’s volume. For medium-to-large systems, the permitted A3 charge is often insufficient. → A2L allows for higher charges, whilst A1 has no limits related to flammability.
- Restrictions imposed by the manufacturer’s manual: If the manual excludes a specific location for the flammable gas model, installation is not permitted. → Choose a suitable A1 or A2L system.
Practical guide for operators and installers
- Follow these steps to correctly certify an A1 or A2L system in place of an A3 system:
- Assess the site: Consider the type of building, the ventilation and the volume of the room.
- Check the regulations: Verify fire safety codes, local regulations and standards EN 378 and IEC 60335-2-40.
- Check whether A3 gas is permitted: If excluded by regulations or charge limits, do not use it.
- Choose the safest alternative: Opt for A2L where permitted, or A1 where maximum safety is required.
- Apply the exemption: No prior authorisation is required; install the unit, stating the safety reason.
- Label the equipment: Include the wording ‘Use prohibited except where required by safety requirements applicable at the place of use’.
- Keep records for at least 5 years: The burden of proof lies with the operator. The documents to be retained include regulatory references, extracts from the manual, copies of labels and, crucially, any risk analysis/assessment or document from the designer.
The key message: Where flammable A3 gases are unsafe or not permitted, A1 and A2L gases are the legal and safer alternative. The safety exemption is specifically designed to make this possible.
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