IE F-Gas Category IV common mistakes
IE F-Gas Category IV · Understand the traps and how to avoid them.
Treating GWP values as interchangeable or guessing a number instead of recalling that R-404A is around 3922 and R-134a around 1430, then multiplying charge mass by the wrong figure for CO2-equivalent reporting.
Candidates memorise 'high GWP' and 'low GWP' labels but never practise the arithmetic, and the exam phrases the question as a CO2e tonne calculation rather than asking for the GWP directly.
What to do instead
Build a short reference table for the common refrigerants (R-134a, R-404A, R-407C, R-410A, R-32, R-744) and rehearse converting kilograms of charge into tonnes CO2e by hand until the division by 1000 becomes automatic.
Confusing the leak-check intervals for hermetically sealed equipment with those for non-hermetic equipment, or applying the 5-tonne threshold to sealed systems that are actually assessed on a different basis.
The thresholds and intervals are a cluster of similar-looking numbers (5, 50, 500 tonnes CO2e and 12, 6, 3 months), and candidates learn them as a list rather than as a decision tree.
What to do instead
Draw the decision tree once: charge in tonnes CO2e, then sealed versus non-sealed, then interval, then whether a leak-detection system halves the frequency. Answer practice questions by walking the tree aloud before choosing.
Recording the recovery cylinder's gross weight rather than the recovered quantity, or omitting the refrigerant type and the destination of the recovered gas from the record.
In the workshop the cylinder is simply weighed, so the tared weight is subtracted mentally and never written down; the paperwork then lacks the figure an inspector would recompute.
What to do instead
Practise writing a complete recovery record from a worked example: cylinder tare, gross weight, net recovered mass, refrigerant identity, date, operator, and where the gas went. Check that every field would let a third party recompute the net figure.
Venting residual refrigerant from a recovered appliance or from the recovery set's hoses to atmosphere because 'it's only a little bit' or because the machine is being scrapped.
Small residual pressures feel harmless and the deliberate-release prohibition is remembered as applying to big systems, not to hose purges or a scrap condensing unit.
What to do instead
Learn the containment rule as absolute: refrigerant is recovered, never vented, regardless of quantity or the fate of the equipment. Rehearse the correct hose-purge procedure using recovery or a closed loop rather than open release.
Selecting a recovery cylinder by size alone without checking its pressure rating and whether it is dedicated to that refrigerant, then overfilling it past the 80 percent liquid-fill limit.
Cylinders look alike, and the fill limit is a percentage of water capacity that is not marked as a weight on the collar, so candidates rely on feel or on the scales stopping at an arbitrary point.
What to do instead
Before recovery, confirm the cylinder's service pressure suits the refrigerant and calculate the maximum fill from its water capacity and the refrigerant's liquid density. Use scales every time and stop at the calculated mass, not at a visual level.
Identifying a refrigerant by the colour of the cylinder or by the system label alone when the label is missing or illegible, and proceeding to recover into an unlabelled cylinder.
Colour coding is convenient and widely used in practice, but it is a convention rather than a guarantee, and mixed refrigerants in an unlabelled cylinder cannot later be reclaimed.
What to do instead
State the identification hierarchy explicitly: system documentation and nameplate first, then cylinder markings, then analysis where doubt remains. Never recover an unknown gas into a cylinder that will be sent for reclamation without flagging it as unknown.
Describing PPE as 'gloves and goggles' without distinguishing task-specific protection, such as cryogenic-rated gloves and a face shield for liquid refrigerant contact versus simple safety glasses for routine leak checking.
The generic phrase is repeated in training and feels sufficient, but exam questions probe the specific hazard of frostbite from a liquid spray or the eye risk from a pressurised jet.
What to do instead
Map PPE to hazard: liquid or high-pressure release means impervious cryogenic gloves and a full face shield; leak detection with an electronic detector means normal site PPE. Learn the first-aid response for skin contact with liquid refrigerant alongside the PPE list.
Entering an enclosed plant room to investigate a suspected refrigerant leak without using a portable detector at the doorway first, or without knowing that refrigerant vapour is heavier than air and collects at low level.
The smell of refrigerant oil or a hiss draws the candidate straight in, and oxygen-displacement risk is associated in candidates' minds with nitrogen rather than with a large refrigerant release in a basement.
What to do instead
Rehearse the entry sequence: detect at the threshold before entry, ventilate, never enter alone, and treat low-lying areas as the danger zone. Link the physical property (vapour density greater than air) to the procedural step so the two are recalled together.
Assuming a blend such as R-407C or R-410A can be topped up as a liquid or vapour without consequence, or treating a zeotropic blend's temperature glide as negligible when charging.
Single-component refrigerants behave simply, and candidates carry that intuition across to blends without accounting for fractional distillation in the cylinder and the composition shift during a vapour leak.
What to do instead
Learn which common refrigerants are zeotropic blends and their approximate glide, then charge blends as liquid and check superheat or subcooling against the manufacturer's data. Be able to explain why a vapour leak from a blend leaves a different composition behind.
Skipping the decommissioning step for equipment being permanently taken out of service, such as failing to recover the full charge, cap the connections, and record the final recovery before the unit leaves site.
Attention is on the installation or repair, and disposal is treated as someone else's job, so the last recovery and its documentation are done hastily or not at all.
What to do instead
Treat decommissioning as a defined procedure with its own checklist: isolate, recover to the required vacuum, cap and label, weigh and record, and note the destination of both gas and equipment. Practise it as a sequence so no step is left implicit.