Compliance4 November 2026 · 4 min read

F-gas leak check frequency: how often, and what to record

Leak checks depend on the refrigerant charge in tonnes of CO2 equivalent, not kilograms. Here are the bands, what they mean in kg for the common refrigerants, and the records you have to keep.

By PPMdesk

In Great Britain, how often a refrigeration, air conditioning or heat pump system must be leak checked depends on how much refrigerant it holds, measured in tonnes of CO2 equivalent (tCO2e): the charge in kilograms multiplied by the refrigerant's global warming potential (GWP), divided by 1,000. The same 5 kg charge can need checking every year with one refrigerant and not at all with another.

The rules come from the F-gas Regulation (EU 517/2014, retained in GB law). DEFRA consulted on reforms in late 2025, but the proposals change the HFC phase-down from 2027, not the leak-check rules below.

Leak check frequency by charge

Charge	Without leak detection	With automatic leak detection
Under 5 tCO2e	No mandatory check	No mandatory check
5 to under 50 tCO2e	At least every 12 months	At least every 24 months
50 to under 500 tCO2e	At least every 6 months	At least every 12 months
500 tCO2e or more	Automatic leak detection is required	At least every 6 months

Hermetically sealed systems under 10 tCO2e have no maximum interval. Leak detection systems must themselves be checked at least every 12 months.

If a check finds a leak, it must be repaired as soon as possible and the system checked again within one month to confirm the repair worked.

What the bands mean in kilograms

Most engineers think in kilograms on the rating plate, so here are the thresholds for the refrigerants you will meet most on commercial sites.

Refrigerant	GWP	5 tCO2e	50 tCO2e	500 tCO2e	Typically found in
R32	675	7.4 kg	74 kg	741 kg	Most new split and VRF air conditioning
R410A	2,088	2.4 kg	24 kg	239 kg	Split and VRF air conditioning, most installed before about 2020
R407C	1,774	2.8 kg	28 kg	282 kg	Older air conditioning and chillers
R134a	1,430	3.5 kg	35 kg	350 kg	Chillers and medium-temperature refrigeration
R404A	3,922	1.3 kg	13 kg	127 kg	Older commercial refrigeration and cold rooms

Charge in kg at which each band starts, from the GWPs in Annex I of Regulation 517/2014. A 3 kg R410A split system is 6.3 tCO2e, so it needs an annual check; the same 3 kg of R32 is 2.0 tCO2e, so it does not.

Who can do the check

Anyone carrying out leak checks, installation, maintenance, servicing or refrigerant recovery on this equipment must hold the appropriate F-gas qualification, and the business they work for must hold an F-gas company certificate from an approved certification body. If you use subcontractors for F-gas work, keep a copy of their company certificate and their engineers' qualifications.

Records you must keep

For every system that needs leak checks, the operator must keep records for at least five years. Where a contractor services the system, they should keep copies too. The record needs:

The type and quantity of F-gas in the system, and its charge in tCO2e
Any refrigerant added, and why
Any refrigerant recovered, and where it went
Who carried out the work, with their certification
The date and result of every leak check, and what was done about any leak

Equipment must also carry a clearly visible label showing that it contains F-gas, which gas, the charge in kg, the charge in tCO2e and the gas's GWP.

Running it on a maintenance contract

For a contractor, the work is less the rule than keeping track of it across hundreds of units: knowing which units are in which band, booking each check before it falls due, sending an engineer with the right certificate, and keeping a record you can produce for a client or an auditor five years later.

Record each unit's refrigerant and charge in your asset register, and work out its tCO2e once.
Set the leak check interval per unit from the table above, not per site.
Put the leak check on the job sheet for that unit, with the charge pre-filled and readings to fill in.
Only send engineers whose F-gas certificate is in date, and keep subcontractors' certificates on file.
Keep the signed job sheet against the unit, so its full history is in one place.

PPMdesk does this as part of planned maintenance: each unit in the asset register holds its refrigerant and charge, engineers record leak checks on the job sheet, and only certified engineers are offered F-gas work. See how it works for HVAC contractors.

Frequently asked questions

How often does a 5 kg R410A system need a leak check?

5 kg of R410A is 10.4 tCO2e, which is in the 5 to 50 tCO2e band, so it needs a leak check at least every 12 months, or every 24 months if it has automatic leak detection.

Do R32 air conditioning units need F-gas leak checks?

Only if the charge is 7.4 kg or more, which is 5 tCO2e for R32. Many small split systems hold less than that and have no mandatory leak check, although a manufacturer or client may still require one.

How long must F-gas records be kept?

At least five years, by the operator of the equipment. Contractors who service it should keep copies for the same period.

What happens if a leak is found?

It must be repaired as soon as possible, and the system must be checked again within one month to confirm the repair has worked.

Sources

Checked on 4 November 2026. If anything here is out of date, tell us and we will correct it.

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