Short answer: multiply the refrigerant charge in kg by its global warming potential (GWP) and divide by 1,000 to get tonnes of CO2 equivalent. In Great Britain, equipment from 5 to under 50 tonnes needs a leak check at least every 12 months, 50 to under 500 every 6 months, and 500 or more every 3 months. A leak detection system doubles each interval.
Work out the leak check interval
Result
| CO2 equivalent | |
|---|---|
| Band | |
| Leak check at least every | |
| Next leak check due by | |
| Leakage detection system required? |
| 5 tonnes CO2e reached at | |
|---|---|
| 50 tonnes CO2e reached at | |
| 500 tonnes CO2e reached at |
The calculator covers stationary refrigeration, air conditioning and heat pump equipment in Great Britain. It does the arithmetic. Nothing you type is stored.
Which rules apply
In Great Britain the leak check duty sits in Regulation (EU) No 517/2014 as it was retained and amended for GB after 31 December 2020. legislation.gov.uk shows no outstanding changes to Article 4 as of 5 November 2026. GOV.UK states that Northern Ireland is part of the EU F gas system, so its rules differ and this calculator does not cover it.
The duty falls on the operator: the person with "actual power over the technical functioning" of the equipment (Article 2). For stationary refrigeration, air conditioning, heat pumps and fire protection equipment, the leak checks must be carried out by certified people (Article 4(2)).
How the calculation works
- Find the charge in kg on the nameplate or in the equipment records.
- Find the GWP of the gas. Single gases are listed in Annex I to the regulation; for blends, Annex IV says the GWP is a weighted average of the parts. GOV.UK publishes both as a list.
- Work out the tonnes of CO2 equivalent: charge in kg ÷ 1,000 × GWP. GOV.UK's own example: 10 kg of R-404A is 0.01 tonnes × 3,922 = 39.2 tonnes CO2e.
- Read off the interval from the table below.
| Tonnes CO2e in the equipment | Without leak detection | With leak detection |
|---|---|---|
| Under 5 | No mandatory leak check | No mandatory leak check |
| 5 to under 50 | At least every 12 months | At least every 24 months |
| 50 to under 500 | At least every 6 months | At least every 12 months |
| 500 or more | At least every 3 months | At least every 6 months |
| Hermetically sealed, labelled as such, under 10 | No mandatory leak check | No mandatory leak check |
Stationary refrigeration, air conditioning, heat pump and fire protection equipment with 500 tonnes CO2e or more must have a leakage detection system that alerts the operator or a service company, and that system must be checked at least once every 12 months (Article 5). In practice, equipment at that size should be on the 6-month interval.
"Hermetically sealed" has a strict meaning: all parts containing F gas are made tight by welding, brazing or a similar permanent connection, with a tested leakage rate of less than 3 grams per year (Article 2). The exemption only applies under 10 tonnes CO2e and only if the equipment is labelled as hermetically sealed (Article 4(1)). GOV.UK gives 10 tonnes as 2.6 kg of R-404A or 7 kg of R-134a.
Worked example: an office with three systems
| Equipment | Gas and charge | Tonnes CO2e | Leak check |
|---|---|---|---|
| Split unit, meeting room | R-410A, 1.8 kg | 3.7584 | No mandatory check |
| Split unit, server room | R-410A, 4.2 kg | 8.7696 | Every 12 months |
| VRF system, open-plan floors, no leak detection | R-410A, 28 kg | 58.464 | Every 6 months |
| Cold room, kitchen | R-404A, 9 kg | 35.298 | Every 12 months |
The VRF system needs two leak checks a year. If the operator fits a leakage detection system that alerts them or the service company, the interval becomes 12 months. The meeting room unit still needs servicing to the manufacturer's instructions, even though the law sets no leak check interval for it.
If a leak is found
- The operator must have the equipment repaired "without undue delay" (Article 3(3)).
- For equipment that needs leak checks, a certified person must check it again "within one month after the repair to verify that the repair has been effective" (Article 3(3)).
- GOV.UK: you could receive a civil penalty if you do not have the right leak checks in place or do not fix leaks.
Who does what
- The operator (often the building owner or occupier) makes sure the checks happen, keeps the records and has leaks repaired. If equipment is rented out, GOV.UK says the rental agreement may make the owner responsible instead.
- The certified engineer carries out the leak check and the follow-up check after a repair.
- The certified company employs them: firms that install, service, maintain, repair or decommission this equipment must hold a company certificate (Article 3(4)).
Before you send an engineer, check their personal F gas certificate and your company certificate. Our guide to subcontractor documents covers what to check for refrigeration subcontractors.
What to record
For each piece of equipment that needs leak checks, Article 6(1) lists the records. GOV.UK says to keep them for 5 years.
- the quantity and type of F gas installed;
- the quantities added during installation, maintenance or servicing, or because of leakage;
- whether installed gas was recycled or reclaimed, with the facility's name, address and certificate number;
- the quantity of F gas recovered;
- the company that installed, serviced, repaired or decommissioned it, with its certificate number;
- the dates and results of the leak checks;
- if decommissioned, how the gas was recovered and disposed of.
Companies that do this work for operators must also keep copies for at least 5 years (Article 6(2)(b)).
F gas checks in Field Suite
- F-gas leak check form: the form library has a ready-made leak check form. It works out the CO2 equivalent from the charge and the gas, sets the next check from the 5, 50 and 500 tonne bands (12, 6 or 3 months, doubled with leak detection), and asks for a follow-up date when a leak is found.
- Sign-off: with the People module on, the form can require an in-date F gas qualification recorded in People and checked by an owner or admin before the engineer signs it off.
- Contracts: visits repeat every set number of months, so 3, 6, 12 and 24-month leak checks fit directly, each created as a job a set number of days before it is due.
- Coming due: certificates due in the next 60 days are listed on the forms page, with a button to book the next visit.
See planned maintenance software, read our PPM schedule guide, check prices, or book a demo.
Field Suite is job management software. The operator and the certified company remain responsible for the leak checks and the records.
Questions
Does a small split system need a leak check?
Only if it holds 5 tonnes CO2e or more. With R-410A that is 2.40 kg or more; with R-32 it is 7.41 kg or more.
Is "every 12 months" the same as once a calendar year?
No. Article 4(3) says "at least every 12 months", so the calculator counts 12 months from the last check.
Which GWP do I use for a blend?
The weighted average set by Annex IV. GOV.UK lists the result for common mixtures, which is what the calculator uses.
Does this apply in Northern Ireland?
No. GOV.UK says Northern Ireland is part of the EU F gas system. Check the Northern Ireland Environment Agency's guidance.
Sources
- Regulation (EU) No 517/2014 as it applies in Great Britain, Article 2. https://www.legislation.gov.uk/eur/2014/517/article/2
- Regulation (EU) No 517/2014 as it applies in Great Britain, Article 3. https://www.legislation.gov.uk/eur/2014/517/article/3
- Regulation (EU) No 517/2014 as it applies in Great Britain, Article 4. https://www.legislation.gov.uk/eur/2014/517/article/4
- Regulation (EU) No 517/2014 as it applies in Great Britain, Article 5. https://www.legislation.gov.uk/eur/2014/517/article/5
- Regulation (EU) No 517/2014 as it applies in Great Britain, Article 6. https://www.legislation.gov.uk/eur/2014/517/article/6
- Regulation (EU) No 517/2014 as it applies in Great Britain, Annex I. https://www.legislation.gov.uk/eur/2014/517/annex/I
- Regulation (EU) No 517/2014 as it applies in Great Britain, Annex IV. https://www.legislation.gov.uk/eur/2014/517/annex/IV
- GOV.UK, Checking F gas equipment for leaks. https://www.gov.uk/guidance/checking-f-gas-equipment-for-leaks
- GOV.UK, Calculate the carbon dioxide equivalent quantity of an F gas. https://www.gov.uk/guidance/calculate-the-carbon-dioxide-equivalent-quantity-of-an-f-gas
- GOV.UK, Fluorinated gases (F gases): list and global warming potentials. https://www.gov.uk/guidance/fluorinated-gases-f-gases
- GOV.UK, Record F gas in equipment you own or service. https://www.gov.uk/guidance/record-f-gas-in-equipment-you-own-or-service
- GOV.UK, Fluorinated gas (F gas): guidance for users, producers and traders (regulators, Northern Ireland). https://www.gov.uk/government/collections/fluorinated-gas-f-gas-guidance-for-users-producers-and-traders
Last checked: 5 November 2026 against the sources above.
Checked in detail: Regulation (EU) No 517/2014 as it applies in GB, Articles 2 to 6 on legislation.gov.uk (no outstanding effects by UK legislation on any of them), GOV.UK F gas list (last updated 7 February 2024) for every GWP value, GOV.UK pages on leak checks (10 t hermetic = 2.6 kg R-404A or 7 kg R-134a, 500 t table, civil penalty, rental), CO2e calculation (10 kg R-404A = 39.2 t), record keeping (5 years) and the collection page (Northern Ireland in the EU system).
Field Suite is job management software for UK building services firms, not a consultancy. Your own risk assessments, contracts and advisers decide what applies to your work. Spotted a mistake? Email info@fieldsuiteapp.com and we correct it.