Practical guide to the relevant safety standards
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In recent years, growing awareness of environmental impact — and specifically the role of refrigerants — has accelerated the adoption of R‑32 VRV systems across Europe. As this transition gains momentum, industry professionals increasingly seek clarity on how to correctly apply the various standards governing F‑gas safety.
Through our leading position in R‑32 VRV solutions and our close collaboration with installers, designers, compliance experts, and policymakers, Daikin has developed a deep understanding of the practical implementation of these safety standards. We have consolidated this knowledge to provide clear, actionable guidance for all stakeholders involved in the design, installation, and assessment of VRV systems.
Which standards regulate refrigerant safety?
IEC 60335-2-40 is a product standard, setting the safety requirements for electrical heat pumps, air-conditioners and dehumidifiers.
EN 378 is a general standard, setting requirements for refrigeration systems, covering design, manufacture, installation, operation, maintenance, and disposal.
Within their scope, both IEC 60335-2-40 and EN 378 state that where a specific safety product standard exists, for example IEC 60335-2-40, it takes precedence over a general standard such as EN 378 (excerpts 1 and 2).
EN 378 further reinforces this principle when defining permitted refrigerant charge limits (excerpt 3).
Conclusion: IEC 60335-2-40 takes precedence over EN 378.
Excerpt 1 – EN378 scope: “Product family standards dealing with the safety of refrigerating systems take precedence over horizontal and generic standards covering the same subject.”
Excerpt 2 – IEC 60335-2-40 scope: “This part of IEC 60335 deals with the safety of electric heat pumps, sanitary hot water heat pumps and air conditioners, incorporating motor-compressors as well as hydronic fan coils units, dehumidifiers (with or without motor-compressors), thermoelectric heat pumps and partial units. Their maximum rated voltage being not more than 300 V for single phase appliances and 600 V for multi-phase appliances.”
Excerpt 3 – EN 378 (part 1): “Article 6 Quantity of refrigerant: Where product standards exist for particular types of systems and where these product standards refer to refrigerant quantities limits, such quantities shall overrule the requirements of this standard.“
- Applying the relevant standards to R-32 A2L systems
- Applying the relevant standards to R-410A (A1) systems
IEC specifies that the most stringent requirement (flammability or toxicity) shall apply (excerpt 4).
Overview of permitted concentration limits for R-32
Safety standard | Max. allowed concentration |
|---|---|
IEC 60335-2-40 | Flammability (LFL): 75% of the lower Flammability Limit (LFL) = 0.75 × 307 g/m³ → 230 g/m³ |
EN 378 | Toxicity (ATEL/ODL): 300 g/m³ |
As the flammability limit of 230 g/m³ is lower than the toxicity limit of 300 g/m³, the more stringent flammability limit applies. Compliance with this limit inherently ensures that toxicity limits are not exceeded, so no additional checks are required.
What does this mean for the design of your R-32 systems?
If the calculated refrigerant concentration is below 230 g/m³, no additional safety measures are required.
Where the concentration exceeds 230 g/m³, Daikin’s Shīrudo Technology supports compliance with IEC 60335-2-40 and EN 378, helping you meet the required safety standards with confidence.
Related to charge limits, IEC only covers flammable refrigerants (A2L, A2, A3).
→ Therefore IEC cannot be used for these evaluations for systems using non-flammable refrigerants (A1).
Overview of permitted concentration limits for R-410A
Safety standard | Max. allowed concentration |
|---|---|
IEC 60335-2-40 | Flammability (LFL): N/A – IEC only covers flammable refrigerants (A2L, A2, A3) |
EN 378 | Toxicity (ATEL/ODL): 440 g/m³ |
The toxicity limit specified in EN 378 for R-410A, classified as an A1 non-flammable refrigerant, is 440 g/m³ and should be applied.
What does this mean for the design of your R-410A systems?
As R-410A does not fall within the scope of the IEC standard relating to refrigerant safety, EN 378 applies as the governing standard.
Refrigerant concentration for R-410A must remain below 440 g/m³. Where this limit is exceeded, appropriate field-supplied safety measures are required in line with EN 378.
Greater design flexibility compared to R-410A systems
By meeting the more stringent IEC requirements, R-32 systems offer significantly greater design flexibility, compared to R-410A equivalents.
Design comparison: Calculation example for a hotel application
For a typical hotel VRV system (8 indoor units, 1 BS box), a VRV 5 system using Shîrudo technology built-in safety measures, only requires a minimum room size of 3.08m², while a similar R-410A systemwould require 12.7m² !
Minimum hotel room area: 3.08 m2
following IEC60335-2-40 and applying Shîrudo Technology
Minimum hotel room area: 12.7 m2
following EN378
More details can be found in our guide:
Frequently Asked Questions
Yes. By designing in line with IEC 60335-2-40 (we ensure compliance), you also meet the relevant requirements of EN 378, including checks on maximum refrigerant concentration per room.
Daikin’s Shīrudo Technology further ensures that refrigerant concentration does not exceed 230 g/m³, equivalent to 75% of the lower flammability limit, as defined in IEC 60335-2-40.
For comparison, a system designed strictly to the EN 378 toxicity limits could allow concentrations of up to 300 g/m³, around 30% more refrigerant in a worst-case leak scenario.
For aspects not covered by IEC 60335-2-40, such as the installation of outdoor units in open air, you should refer to EN 378 for guidance.
Yes. EN 378 is a general standard, and within its scope and Clause 6, it refers directly to applicable product standards, in this case IEC 60335-2-40.
Compliance with IEC 60335-2-40 therefore constitutes compliance with EN 378 for the areas covered by that product standard.
No. Compliance with IEC 60335-2-40, and consequently EN 378 Parts 1 and 2, is sufficient. There is no requirement to apply EN 378-3, including provisions such as an independent power supply for the leak detection system.
EN 378 Table C.1 sets charge limits based on the toxicity limit multiplied by room volume, or as defined in Clause C.3. In practice, the applicable charge limit is always determined using the more stringent criterion. The toxicity limit is therefore not exceeded.
As a result, the additional safety measures described in EN 378-3, Clause C.3, are not required.
This approach aligns with established practice for A-class refrigerants, such as R-410A, where no additional safety measures are needed provided toxicity limits are not exceeded.
Daikin’s unique Shîrudo Technology addresses all relevant IEC requirements, delivering compliant system design and peace of mind straight out of the box.
No complex safety measure calculations required
No additional installation or commissioning work
No visual impact from extra sensors or components
No additional work or redesign if the layout changes
No requirement for periodic safety checks
How Shîrudo Technology works
- Integrated sensors to detect refrigerant leak
- Integrated alarm
- Shut-off valves
Integrated sensors to detect refrigerant leak
- Integrated in every indoor unit
- Self-monitoring, detects even the smallest refrigerant leak
- Automatically activates refrigerant response measures: an alarm and shut off valves
Integrated alarm
- Local visual and audible alarm integrated in Madoka wired remote control
- An additional supervisor alarm can be integrated via:
- A field setting on the Madoka controller
- An input signal that triggers a 3rd party alarm
To ensure compliance to IEC60335-2-40 for even the smallest rooms shut off valves are provided.
Depending on the system, these are either integrated in the outdoor unit or (BS)SV box. In case of a leak the refrigerant is either pumped back to the outdoor unit or specific branches are closed to contain the leak and minimize the refrigerant that can leak.
