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R290 (propane) air conditioning in commercial buildings

Updated 23 October 2026 · SEO Dons Editorial

What is R290, and is it an F gas?

R290 is refrigerant-grade propane. One supplier describes it as a hydrocarbon that, although highly flammable, is an efficient refrigerant with a low global warming potential. Great Britain's Regulation 517/2014 lists propane (R-290) at a GWP of 3, but only as a non-fluorinated substance used to calculate the GWP of mixtures.

It is not an F gas. GOV.UK uses the term F gases for hydrofluorocarbons, perfluorocarbons and sulphur hexafluoride, and says equipment that uses hydrocarbons needs no HFC quota authorisation. The company certification GOV.UK describes is for equipment containing F gas, so a propane-only circuit falls outside it. The competence question moves to flammable-refrigerant training: REFCOM notes that the BESA Academy runs a short online course, "Working with Flammable Refrigerants", for qualified F-gas engineers, and that ACRIB SKILLcards clarify which refrigerants an operative is qualified to work with.

Is R290 mandatory for new commercial air conditioning?

No. GOV.UK's bans table restricts new single split systems under 3kg to a GWP of 750 or below from 2025. R32, at 675, sits under that line, and the table's exceptions include larger systems such as chillers. Propane is one compliant route, not the only one. The 2026-27 changes page covers what Defra has and has not decided on the phasedown, and the R32 versus R454B page covers the A2L alternatives.

Where is R290 used in commercial buildings?

The common thread is a charge that stays outdoors or in a plant area, with water carrying the heating or cooling into the building. Examples from manufacturers' own pages:

  • Daikin Applied UK's R-290 chillers and heat pumps span 17 kW to 2,000 kW. Its EWAK-CZ is a monobloc air-to-water cooling-only unit of 20 to 85 kW.
  • Rinnai UK lists R290 water chillers and reversible heat pumps from 40 kW to 410 kW.
  • Split systems exist too. The International Institute of Refrigeration says India has led in R290 split room air conditioners, but that elsewhere market introduction is limited except for small and portable units.

The design principle is the same everywhere. According to the Institute, safety shut-off valves can keep the charge mostly in the outdoor section of a split system, limiting what can leak indoors. CIBSE Journal describes hybrid VRF systems that put all refrigerant-containing components outside commonly occupied spaces and use water for heat distribution.

Why do charge limits restrict R290 indoors?

The Institute calls R290 a class A3 refrigerant, "highly flammable", which presents a risk in the event of a leak. CIBSE Journal gives the minimum ignition energy of a typical A2L as 10 J, against about 0.0003 J for methane, and a quenching distance of 8 to 25 mm against about 1.5 mm for propane. A3 therefore tolerates far less leaked gas in a room.

Two standards set the limits:

  • BS EN 378. BSI says Part 1 applies to refrigerating systems of all sizes and helps determine the maximum charge suitable for the room volume. Part 3 covers the installation site, including plant space, and its 2020 revision considered 2L refrigerants and separate machinery rooms.
  • IEC 60335-2-40. This product standard covers factory-made air conditioners and heat pumps, including those used by laymen in shops, light industry and on farms. It excludes appliances designed exclusively for industrial processing. The IEC's page lists edition 7 (2022) and says a more recent version exists, so the edition in use matters.

The two are generally consistent. CIBSE notes they use the same intrinsic safety equation for minimum room floor area, and that product family standards take precedence over the horizontal EN 378 where they cover the same subject, including quantity limits. The Institute adds that the 2022 edition of IEC 60335-2-40 aims to keep the releasable charge from producing a concentration above 50% of the lower flammability limit, and allows higher charges where extra measures such as shut-off valves are used. Both standards are sold, not published openly, so this page gives no kilogram limits for R290. The designer's calculation for the actual room is the test.

What does DSEAR add?

HSE says the Dangerous Substances and Explosive Atmospheres Regulations 2002 require employers to find out what dangerous substances are in the workplace and what the risks are, and to identify areas where explosive atmospheres may occur and avoid ignition sources. Its examples of dangerous substances include flammable gases such as LPG. CIBSE says all refrigerants in the UK are subject to DSEAR, with risk assessment plus leak detection, ventilation, shut-off valves and alarms as the usual safeguards. Daikin's R-290 range, for instance, builds in continuous leak detection, ATEX-certified switchbox ventilation, visual and acoustic alarms, and an independent 230V supply for monitoring. The ATEX air conditioning page covers zoning in more depth.

Industry guidance covers the whole life of the system. The Institute of Refrigeration publishes a safety code for flammable lower-toxicity refrigerants in groups A2L, A2 and A3. It covers design, testing, maintenance and decommissioning, and is a guide to interpreting BS EN 378:2016 and legal requirements such as PED, PSSR and PUWER.

Pressure equipment rules also bite. CIBSE says systems with A2L and A3 refrigerants are more likely to fall in Category 2 or above, which needs assessment by an Approved Body before the UKCA mark can be applied to the installed system.

How does R290 compare with R32?

PointR290 (propane)R32
GWP, GB basis3675
Safety classA3A2L
F gas statusNot an F gas; no HFC quota authorisationHFC: leak-check bands apply, starting at about 7.4 kg (5 tonnes CO2e)
Typical commercial useChillers and heat pumps with outdoor charge; some splitsSplit and multi-room air conditioning
Indoor charge limitTighter, from A3 flammabilityLess tight, as the CIBSE room-area example shows
GB product ban exposureNone listedUnder the 750 GWP line for small single splits

No neutral source compares their efficiency across commercial products, and manufacturers describe both as efficient. Compare the SEER and SCOP figures on each datasheet instead; the SEER page explains them. Servicing differs as well, because the supplier notes that propane needs different charging and recovery procedures.

What should a buyer ask about an R290 proposal?

  • The charge per circuit and where it sits, outdoors or in the building.
  • Which standard and edition the design follows, and the room-by-room check where relevant.
  • Who holds the DSEAR risk assessment, and what the leak detection does on alarm and on power loss.
  • Evidence of the engineers' flammable-refrigerant training.

Those questions apply equally to air conditioning replacement projects. The refrigerant GWP table shows where R290 sits among the alternatives, and readers who want quotes can send an enquiry through the site's form.

Sources

Common questions

Is R290 banned or mandatory in the UK?

Neither. GOV.UK's bans table has no entry for propane, and the single split limit of GWP 750 from 2025 can be met by R32 at 675 as well as by propane. R290 is an option, not a requirement.

Does an R290 system need an F-gas certified engineer?

GOV.UK describes F gas certification for equipment containing F gas, and propane is not one. A propane circuit still needs engineers trained for flammable refrigerants and a DSEAR risk assessment, so ask for evidence of both.

Can R290 go in an ordinary office split system?

It depends on the charge and the room. IEC 60335-2-40 and BS EN 378 limit the charge in occupied spaces, and the limits depend on the edition and the unit. The manufacturer and designer should show the check for each room served.

Is R290 more efficient than R32?

No neutral source settles this across commercial products. Manufacturers describe propane as efficient, but results depend on the model. Compare the seasonal efficiency figures on each datasheet at the same conditions.

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