F-Gas Category I common mistakes
F-Gas Category I · Understand the traps and how to avoid them.
Treating the F-Gas leak-check intervals as a single fixed period and stating that every system must be checked every 12 months regardless of charge size.
Candidates memorise one number and stop there, missing the tiered thresholds (5 t CO2e, 50 t CO2e, 500 t CO2e) that shorten the interval and the CO2e conversion that decides which tier applies.
What to do instead
Learn the decision path: convert charge mass to CO2e using the refrigerant's GWP, then map to the interval (12, 6, or 3 months) and note the doubling rule when leak-detection systems are fitted. Practise converting a charge in kg to tonnes CO2e for several refrigerants.
Recording a leak check as complete without logging the calculated CO2e charge, the GWP used, or the date and identity of the checker.
Candidates focus on the physical test and treat paperwork as an afterthought, so they omit the data fields that make a record compliant and auditable.
What to do instead
Before answering record-keeping questions, list the mandatory fields: date of check, refrigerant type, charge in kg and in tonnes CO2e, GWP value used, leak-detection method, and the person's name/competence. Check each field against the question stem.
Assuming a system that has been retrofitted to a lower-GWP refrigerant keeps its original leak-check frequency and record thresholds.
Candidates carry over the old charge-size classification without recalculating, not realising the CO2e figure changes with the new GWP.
What to do instead
Always recompute tonnes CO2e after any refrigerant change and state explicitly that the frequency tier must be reassessed. Treat the retrofit as a new baseline for records.
Confusing recovery, recycling, and reclaim, and describing recycled refrigerant as if it were reclaimed product.
The three terms sound similar and candidates learn them as synonyms rather than as a hierarchy of cleanliness and destination.
What to do instead
Anchor each term to its destination: recovery = removal and storage; recycling = cleaned on site for reuse, no full analysis; reclaim = reprocessed to virgin specification with analysis and certification. Match the term to whether the refrigerant may be charged into another owner's equipment.
Answering leak-detection questions by choosing the cheapest or quickest method (soap bubbles, electronic probe only) without considering the required sensitivity, location, or confirmation step.
Candidates default to the method they have seen used, ignoring that different situations (underground pipework, inaccessible joints, oxygen-depleted spaces) demand specific techniques or a follow-up confirmation.
What to do instead
Build a method-to-situation table: electronic detector for general joint checking, UV dye or pressure/standing test for concealed or buried sections, and a documented confirmation and repair-verification step. Read the stem for the constraint (access, location, refrigerant type) before selecting.
Selecting a recovery cylinder by size alone and ignoring its pressure rating, refrigerant compatibility, and the fill limit.
Candidates treat cylinders as generic containers and forget that recovered refrigerant may be a different pressure class and that overfilling is a safety and legal issue.
What to do instead
Check three things before answering: the cylinder's design pressure against the refrigerant, that it is dedicated to that refrigerant (labelled), and that the fill stays within the safe fill density/weight limit. State the check sequence rather than just naming a cylinder.
Describing recovery as finished when the system pressure reads zero, without addressing residual refrigerant in oil, or the evacuation and safe disposal of the recovered gas.
Candidates equate 'no pressure' with 'empty', overlooking refrigerant dissolved in lubricant and the requirement to handle the recovered charge properly.
What to do instead
Include the residual step: recover from oil where relevant, confirm the system is at the required vacuum/pressure, then state where the recovered refrigerant goes (reclaim, recycle, or destruction) and how the cylinder is labelled and stored.
Mixing up GWP and ODP and applying the wrong metric to a refrigerant.
Both are environmental impact numbers and candidates use them interchangeably, especially for blends and HCFCs where both matter.
What to do instead
Separate the concepts: ODP relates to ozone depletion (chlorine/bromine content), GWP relates to climate impact over a time horizon. For each refrigerant, state which metric drives the regulatory duty (GWP for leak checks and CO2e; ODP for phase-out of ozone-depleting substances).
Handling a leak or spill scenario by starting with the repair rather than isolating, ventilating, and making the area safe.
Candidates jump to the technical fix and forget the safety sequence, especially for flammable or asphyxiant refrigerants in confined spaces.
What to do instead
Answer scenario questions in order: make safe (isolate, ventilate, exclude ignition sources, use PPE and gas detection), then assess and repair, then verify and record. State the sequence explicitly.
Treating commissioning records as a formality and omitting the pre-charge checks (pressure/leak test, evacuation and dehydration, charge verification) from the answer.
Candidates focus on the final charge figure and skip the steps that prove the system is leak-free and dry before refrigerant is added.
What to do instead
For commissioning questions, list the sequence: strength/pressure test, leak test, evacuation to target vacuum and hold, then charge and record actual charge against design. Include the record fields for each step.