If your equipment holds 5 tonnes of CO2 equivalent (tCO2e) or more of F-gas, it must be leak checked on a schedule set by its charge: at least every 12 months from 5 tonnes, every 6 months from 50 tonnes. The equipment user is normally responsible for arranging the checks. You must keep the records for 5 years. This guide covers what counts as covered equipment, how to work out your charge, the frequency at each level, the exemptions, what to do when a leak is found, and how to keep records that stand up to inspection.
TL;DR
- Leak checks apply to covered equipment holding 5 tCO2e or more of F-gas. The charge is the amount of gas weighted by its global warming potential.
- From 5 to under 50 tCO2e, check at least every 12 months. From 50 to under 500 tCO2e, at least every 6 months.
- Automatic leak detection doubles the permitted gap between checks, but the detection system itself needs checking too.
- When a leak is found, repair it without delay and run a follow-up check within one month.
- Keep records for 5 years: gas quantities and types, check dates and results, and the details of the companies who worked on the kit.
Table of Contents
- Which equipment and operators are covered
- How to work out your charge in tCO2e
- How often you must leak check
- Who can carry out the check
- What to do when a leak is found
- F-gas leak check records: what to keep and for how long
- A simple compliance routine for multi-site operators
- Keeping F-gas records without the admin
- FAQ
- Sources
Which equipment and operators are covered
The GOV.UK guidance on checking F-gas equipment for leaks applies the requirement to stationary refrigeration, air-conditioning, heat-pump and fire-protection equipment. It also covers the refrigeration units of refrigerated trucks and trailers, electrical switchgear, and organic Rankine cycles. The trigger is a charge of 5 tCO2e or more.
Three practical points follow from that list:
- It is about the equipment, not the building. A site with several small split systems can be covered even if each unit feels minor, so count per piece of equipment and check where the threshold sits for each.
- Foams are out. The September 2024 F-gas guidance states that leak check requirements do not apply where the F-gas is contained in foams.
- The operator carries the duty. GOV.UK says the user of the equipment is responsible for getting it checked. If the equipment is rented out, the owner may be responsible instead, depending on the rental agreement. Landlords, facilities managers and tenants should settle this in writing, not assume it.
Do the rules differ across the UK?
The EU Withdrawal Act kept EU F-gas legislation in UK law, and later regulations set separate arrangements for Great Britain and Northern Ireland, according to the September 2024 guidance. If you run sites on both sides of the Irish Sea, confirm which regime applies to each site rather than applying one schedule everywhere.
How to work out your charge in tCO2e
The leak check frequency depends on the amount of F-gas and its global warming potential (GWP). The charge is expressed as the equivalent weight of carbon dioxide, as GOV.UK explains.
In practice that means three inputs: the kilograms of refrigerant in the system, the GWP of that specific gas, and a conversion to tonnes. Multiply the charge in kilograms by the GWP, then divide by 1,000.
A purely illustrative example: a system holding 10 kg of a gas with a GWP of 2,000 has a charge of 20 tCO2e (10 × 2,000 ÷ 1,000). That puts it in the 5 to under 50 band. Swap in a lower-GWP gas and the same 10 kg could fall below 5 tCO2e and out of scope. This is why the gas type on the nameplate and in your records matters as much as the quantity.
Two habits stop errors here:
- Record the gas type and the charge on the asset register the day the equipment is installed, not when the first check falls due.
- Re-calculate after any top-up or retrofit that changes the gas or the quantity. A system can move between bands.
How often you must leak check
The frequencies below come from the GOV.UK leak check guidance.
| Charge (tCO2e) | Minimum check frequency |
|---|---|
| Under 5 | No mandatory leak check under these rules |
| 5 to under 50 | At least every 12 months |
| 50 to under 500 | At least every 6 months |
| 500 or more: electrical switchgear or organic Rankine cycles installed before 1 January 2017 | Every 3 months |
For other equipment at 500 tCO2e or more, read the frequency on the GOV.UK page itself and apply it to your asset. Large systems are the ones where a missed interval is most expensive, so do not work from a summary table alone.
These are minimums. Equipment that has a history of leaking, runs hard, or sits in a hard-to-reach location may justify checking more often through your planned maintenance programme.
Automatic leak detection
Fitting an automatic leak detection system doubles the permitted period between checks. That could move a 6-monthly system to 12-monthly. The system is not set-and-forget: GOV.UK states the detection system must be checked every 6 years on electrical switchgear and every year on other equipment. Put that annual check in the same schedule as the leak checks so it does not slip.
Hermetically sealed systems
Hermetically sealed refrigeration and air-conditioning systems containing less than 10 tCO2e have no maximum period between checks, per the same guidance. That does not mean the equipment never needs attention. It means the fixed interval does not apply, and you should still keep the gas type and charge on file.
Electrical switchgear exemptions
The September 2024 guidance says electrical switchgear is exempt from leak checks if any one of these applies:
- it has a tested leak rate of less than 0.1% per year and is labelled as such;
- it is fitted with a pressure or density monitoring device; or
- it contains less than 6 kg of F-gas.
Keep evidence of whichever exemption you rely on, such as the label or the monitoring device specification, in the asset file.
Who can carry out the check
Operators must identify and stop leaks using qualified personnel, either from inside the organisation or from certified service companies. The September 2024 guidance describes responsibility as shared between operators and the service companies they employ. Repairs, and confirmation that a repair worked, must also be done by suitably qualified personnel.
If you use a contractor, ask for their F-gas certificate details before the visit and store them with the job. Those details are also a record-keeping requirement, as the next sections show. If your own engineers do the work, track their certification expiry so no one is sent to a covered system with lapsed credentials. Our guide on engineer certification tracking sets out a workable routine.
What to do when a leak is found
The operator must make sure the leak is repaired without delay and that the repair is verified by a subsequent check. An additional follow-up check must be carried out within one month to confirm the repair is effective, as the September 2024 guidance sets out.
A clean sequence looks like this:
- Log the leak against the specific asset, with date, location on the system and how it was found.
- Book a suitably qualified engineer to repair it, without delay.
- Verify the repair with a check at the time of the repair.
- Diarise the follow-up check inside one month, and assign it to a named person.
- Record the gas added, the check results and the outcome on the asset history.
The follow-up is the step most often forgotten, because the job feels closed once the engineer leaves site. Creating it as a scheduled job at the moment the repair is booked removes the reliance on memory.
F-gas leak check records: what to keep and for how long
Records must be kept for 5 years, according to GOV.UK's record-keeping guidance. They must include:
- the quantity and type of gas when installed, and any gas added during maintenance;
- the dates and results of mandatory leak checks;
- what was done to recover and dispose of gas; and
- the names, addresses and certificate numbers of the companies used to install, service or decommission the equipment.
The Environment Agency may ask to see these records during an inspection, per the same page. In practice, the question is rarely whether a check happened. It is whether you can prove it quickly, for the right asset, with the right gas type and a named, certified engineer.
Where records usually fall down
- Paper logbooks on the unit. They get wet, filled in late, or left behind when the equipment is replaced.
- Contractor reports in an inbox. The check happened, but nobody can find the PDF a year later.
- No link between the check and the asset. A report that says "AC unit, first floor" is weak evidence on a site with six of them.
- Gas top-ups recorded on invoices only. The quantity is there, but not where the compliance manager looks.
We go deeper on structuring this data in our piece on mapping GOV.UK F-gas duties to audit-ready records. For a wider view of how to prove work was done properly on any job, the job audit checklist is a useful companion.
A simple compliance routine for multi-site operators
Whether you run five assets or five hundred, the routine is the same:
- Build the register. Every piece of covered equipment, with location, gas type, charge, calculated tCO2e and install date.
- Set the interval from the band. 12 months, 6 months, or the interval for your larger equipment, doubled only where automatic leak detection is genuinely fitted and itself checked.
- Generate the jobs automatically. Do not rely on a spreadsheet reminder that one person owns.
- Capture the evidence on site. Result, gas quantities, engineer name and certificate number, photos of nameplate and detection equipment.
- Trigger the follow-up. Any leak found creates a repair job and a one-month verification job.
- Review quarterly. Look for overdue checks, repeat-leak assets and equipment that has changed band.
Facilities teams managing many sites also need this tied to service-level agreements, so a missed check shows up as a risk before it becomes a finding. Our facilities management software is built around that multi-site view.
Our view: compliance should fall out of the job, not sit beside it
We built Curcle inside a real UK service and engineering business, and F-gas is a good example of where disconnected tools hurt. The rule itself is not complicated: a threshold, an interval, a follow-up, five years of records. The difficulty is joining the asset, the gas charge, the engineer's certificate and the job report so they agree with each other months later.
That is why we treat compliance as part of the platform backbone, not a module bolted on. When the asset register holds the gas type and charge, the next check can be scheduled from it. When the engineer completes the job on the mobile app, even offline, the result, photos and certificate details land on that asset's history. When an inspector asks, you export one record, not a folder hunt.
We also think software should show you what needs attention, not just log what already happened. An overdue 6-monthly check or an unscheduled one-month follow-up is exactly that kind of signal. AI can help surface it, but the judgement on a leak stays with your qualified engineer.
Luke Herridge
Keeping F-gas records without the admin
If you manage covered equipment across several sites, our refrigeration software keeps F-gas records and asset history in one place, so checks, top-ups and certificates stay linked to the right unit. Jobs can be scheduled from the asset register, completed by engineers in the field, and exported for audit when needed. You can see how the pieces connect on our workflows page and compare plans on the pricing page: Starter is from £99 per month, Professional from £249 per month and Business from £499 per month, with Enterprise priced on request.
If you also handle gas appliances or water systems, the same record-first approach applies. See our notes on Gas Safe engineering software and on water hygiene record keeping.
FAQ
How often does an F-gas system need a leak check?
Equipment holding 5 to under 50 tCO2e needs a check at least every 12 months. From 50 to under 500 tCO2e it is at least every 6 months. Switchgear or organic Rankine cycles installed before 1 January 2017 with 500 tCO2e or more need checks every 3 months. Automatic leak detection doubles the permitted period.
Who is responsible for arranging the leak check?
The user of the equipment is responsible for getting it checked. If the equipment is rented out, the owner may be responsible instead, depending on the rental agreement. Agree this in the lease or service contract so there is no gap on a shared or sublet site.
How long do I keep F-gas leak check records?
Five years. The records should show gas quantity and type at installation and on top-up, the dates and results of leak checks, what was recovered or disposed of, and the names, addresses and certificate numbers of the companies who worked on the equipment. The Environment Agency may ask to see them.
What happens after a leak is found?
The operator must have it repaired without delay by suitably qualified personnel, and the repair must be verified by a check. A further follow-up check is needed within one month to confirm the repair is effective. Record both checks on the asset history.
Do small or sealed systems need leak checks?
The mandatory checks start at 5 tCO2e. Hermetically sealed refrigeration and air-conditioning systems under 10 tCO2e have no maximum period between checks. Work out the charge in tCO2e for each unit and keep that calculation on file.
Sources
- Checking F gas equipment for leaks, GOV.UK
- Record F gas in equipment you own or service, GOV.UK
- Fluorinated greenhouse gases guidance, September 2024, GOV.UK