The European Committee for Standardization (CEN) has released an updated draft version of safety standard EN 378 for voting and comments by national standardization committees and other stakeholders.
The draft version – officially prEN 378:2025 – was issued on July 3 and will be open for voting and comments until September 25. A final vote will occur in 2026.
The national standards bodies in the 34 CEN member states, which will vote on the proposed standard, provide a means for individuals to access the draft standard and submit comments. Interested stakeholders can visit the website of their national standards body such as in Spain, the Netherlands, Ireland and the U.K.
The new version contains “significant advances for natural refrigerants,” particularly for hydrocarbons, according to a eurammon webinar on August 19 given by Daniel Colbourne, Co-Owner of U.K. consulting firm Re-Phridge, which specializes in low-GWP refrigerants, including flammables. “Historically, [the standard’s] requirements have been reasonable for R744 [CO2] and R717 [ammonia] but very obstructive for hydrocarbons.”
It is essential that prEN 378:2025 receive positive votes and that stakeholders submit comments for clarification and technical corrections to counter the “considerable opposition from anti-natural [refrigerant] interest groups,” said Colbourne, adding, “Negative votes will be used as justification to tone down elements that support naturals.” Most problems in the prEN draft relate to “flow (logic), clarity [and] interlinkages between requirements,” he said.
It would be “catastrophic” for any part of the updated standard to fail, said Colbourne.
The proposed standard, which would update the current edition (EN 378: 2016), lists requirements for the design, testing, installation and operation of refrigeration, air- conditioning and heat pump systems, ranging from small to large capacities.
It consists of four parts:
- prEN 378-1 – general, definitions, charge limits
- prEN 378-2 – system design, construction and testing
- prEN 378-3 – installations
- prEN 378-5 – refrigerant data
Part 4 on operation, maintenance, repair and recovery is being replaced by ISO 5149-4.
The main changes to the standard regarding refrigerant charges are in part 1, noted Colbourne.
Natural refrigerant trade group eurammon said it “welcomes the standard’s more flexible and risk-based design approach, which could better accommodate the unique properties of natural refrigerants such as R717, R744 and hydrocarbons.” However, the group is urging further improvements, particularly to “charge limit restrictions and overly prescriptive safety caps that still pose barriers to wider application of natural refrigerants.”
eurammon is encouraging stakeholders “to support the revised standard by voicing expressions of approval to national standardization committees.”
The European FluoroCarbons Technical Committee, which represents chemical producers, declined to comment on prEN 378:2025.
Changes in part 1
According to Colbourne, the major changes in part 1 of the proposed EN 378 standard involved:
- Determination of room size (for refrigerant amounts)
- Determination of refrigerant amounts
- Intrinsic and extrinsic design methods
- Capped quantity limits
- Refrigerant quantity safety limits (charge limits)
- The releasable charge concept
- Integrated mitigation measures
- Surrounding concentration testing
EN 378 does not set a single hydrocarbon charge limit for equipment like commercial cabinets, but provides a calculation method and maximum values that depend on the refrigerant type, the room size, and the safety classification of the equipment and location.
The general standard EN 378 establishes different classes of location and access categories, which determine the maximum refrigerant charge that can be used considering the flammability (and toxicity) class of the refrigerant. For instance, a system with a high quantity of flammable refrigerant may need to be located in a machinery room, with a certain type of access, or in a room with a ventilated enclosure or outdoors, noted component manufacturer Carel.
Colbourne explained the specific changes in quantity limit requirements for flammable refrigerants in a presentation last year in Dublin for the Institute of Refrigeration Ireland.
The charge limits for flammable refrigerants can be found in a number of international standards for refrigeration, air conditioning and heat pumps, including ISO 5149, IEC 60335-2-40 and IEC 60335-2–89. In Europe, in additional to EN 378, there are EN versions of the IEC standards, while other regions have their own versions of the global standards.
This results in varying charge levels for hydrocarbons. For instance, noted the International Institute of Refrigeration (IIR), the upper charge limit for domestic refrigeration is 150g, while the upper charge limit for commercial refrigeration ranges from 500g to 1.5 kg depending on the standard.
“Negative votes will be used as justification to tone-down elements that support naturals.”
Daniel Colbourne, co-owner of Re-phridge
