Based on the GB F-Gas Regulation (assimilated Reg 517/2014) thresholds and IPCC AR4 GWPs. Hermetically sealed equipment is exempt below 10 t CO₂e. Records and leak checks must be carried out by an F-Gas certified engineer — this is a guide, not compliance advice.
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This calculator converts a refrigerant charge into its CO₂ equivalent and tells you the mandatory leak-check interval. Choose the refrigerant, enter the charge in kilograms and say whether a fixed leak detection system is fitted, and it returns the tonnes of CO₂e and how often the system must be checked for leaks.
It is for refrigeration and air-conditioning engineers who need to know where a system sits against the F-Gas thresholds. The leak-check duty is set by CO₂ equivalent, not by weight of gas, so a small charge of a high-GWP refrigerant can carry the same obligations as a much larger charge of a low-GWP one.
The calculation multiplies the charge by the refrigerant's global warming potential (GWP) and divides by 1,000 to give tonnes of CO₂e, then reads that figure against the GB F-Gas leak-check tiers. A fitted leak detection system relaxes the interval by one tier.
Tonnes CO₂e = charge (kg) × GWP ÷ 1000
Global warming potential (GWP) expresses how much heat a refrigerant traps compared with the same mass of CO₂ over 100 years — R32 has a GWP of 675, R410A of 2,088, R404A of 3,922, while R290 (propane) is 3. Multiplying the charge in kilograms by the GWP and dividing by 1,000 gives the CO₂ equivalent in tonnes. So 3 kg of R410A is 3 × 2088 ÷ 1000 = 6.26 t CO₂e.
Choose the refrigerant from the list — R32, R410A, R407C, R134a, R404A, R507A, R290 or R744. Each carries its GWP, which is what determines the CO₂ equivalent. The gas type matters as much as the quantity.
Type the total refrigerant charge in the system in kilograms, from the nameplate or commissioning records. Use the full system charge, not a top-up amount, as the thresholds apply to the whole charge.
Select whether a fixed leak detection system is installed. A permanent LDS that alerts the operator to a leak allows the leak-check interval to be relaxed by one tier under the regulation.
The calculator shows the charge as tonnes of CO₂e and the mandatory leak-check frequency for that tier — no check below 5 t, then 12, 6 or 3-monthly as the tonnage rises, each relaxed by one step where an LDS is fitted.
The leak-check tiers come from the GB F-Gas Regulation (assimilated Regulation 517/2014). Below 5 t CO₂e there is no mandatory periodic check; from 5 to under 50 t it is every 12 months (24 with a leak detection system); from 50 to under 500 t it is every 6 months (12 with an LDS); and at 500 t or more it is every 3 months (6 with an LDS). Hermetically sealed equipment is exempt from checks below 10 t CO₂e.
Because the duty is driven by CO₂ equivalent, the choice of refrigerant changes everything. The same 4 kg charge is under 3 t CO₂e as R32 but over 15 t as R404A — the latter crosses into mandatory checking while the former does not. This is a large part of why the industry is moving toward lower-GWP gases like R32 and R290.
Only F-Gas certified engineers may install, service, decommission or leak-check this equipment and handle the refrigerant, and records must be kept. This tool tells you where a system sits against the thresholds so you can plan the check regime, but it is general guidance, not compliance advice — always work to the current regulation and your certification body's requirements.
Based on the GB F-Gas Regulation (assimilated Reg 517/2014) thresholds and IPCC AR4 GWPs. Hermetically sealed equipment is exempt below 10 t CO₂e. Records and leak checks must be carried out by an F-Gas certified engineer — this is a guide, not compliance advice.
Multiply the refrigerant charge in kilograms by the gas's GWP, then divide by 1,000. For example, 2.5 kg of R32 (GWP 675) is 2.5 × 675 ÷ 1000 = 1.69 t CO₂e. The same 2.5 kg of R410A (GWP 2,088) is 5.22 t CO₂e — enough to cross into the mandatory leak-check band.
It depends on the CO₂ equivalent of the charge. Below 5 t there is no mandatory periodic check; 5 to under 50 t needs a check every 12 months; 50 to under 500 t every 6 months; and 500 t or more every 3 months. Fitting a fixed leak detection system halves the frequency in each band — for example 24 months instead of 12.
GWP, or global warming potential, is how much heat a refrigerant traps in the atmosphere compared with the same weight of CO₂ over 100 years. CO₂ itself is 1. R32 is 675, R410A is 2,088 and R404A is 3,922, so a kilogram of R404A does nearly 4,000 times the warming of a kilogram of CO₂ — which is why the leak-check duty is based on CO₂ equivalent rather than weight.
Yes. A fixed, permanently installed leak detection system that warns the operator of a leak lets you relax the mandatory leak-check interval by one tier under the F-Gas rules — for instance, from 12 months to 24, or from 6 months to 12. It does not remove the duty, but it reduces how often the manual check is required.
Yes. Installing, servicing, leak-checking and decommissioning F-Gas equipment, and recovering or handling the refrigerant, must be done by an appropriately F-Gas certified engineer, and records have to be kept. This calculator is a planning aid to show where a system sits against the thresholds — it is guidance, not a substitute for the regulation or your certification requirements.