The Cold Store Log with Gaps and a Dead Detector
A cold store distribution depot runs a single R-404A low-temperature condensing unit with a nameplate charge of 180 kg. A fixed refrigerant detection system was fitted in 2019, but the maintenance file shows no calibration or bump test since commissioning, and the operator says it 'beeps sometimes'. The F-gas log is a ring binder with two handwritten pages: one entry from 2021 reading 'leak on liquid line - gassed up', and one from last month reading 'service'. The depot manager argues that because the detection system is fitted, the unit only needs checking every 12 months, and that the binder is enough 'because everything is in there'. A pinhole leak has just been found on the condenser coil.
1. Calculate the CO2-equivalent of the unit and state the correct leak-check interval. Explain whether the detection system changes it.
Read the worked answer
Calculation
- 180 kg x GWP 3922 (R-404A) = 705,960 kg CO2e = 706 tonnes CO2e
Interval
- At or above 500 t CO2e, the base interval is every 3 months.
- A properly functioning fixed leak detection system allows the interval to be doubled, to every 6 months.
- The manager's '12 months' is wrong on any reading: it is not a permitted interval for this charge at all.
The catch The interval can only be doubled if the detection system is genuinely functional, and the operator must have it checked at least once every 12 months. This one has had no calibration or bump test since 2019, and 'beeps sometimes' suggests it may be a nuisance-alarm fault rather than a working detector. Until it is calibrated, tested with a known challenge gas and documented, it cannot be relied on.
Practical answer: the unit must be leak-checked every 3 months now, and the detection system should be serviced and certified; only then can the interval move to 6 months. Given a pinhole has just been found, the immediate priority is repair and a verification check, not arguing about intervals.
2. Assess the logbook against the record-keeping requirements and list what is missing.
Read the worked answer
The binder is not a compliant record. Two lines do not capture what the regulation requires for a unit above 5 t CO2e.
What must be present
- Type of refrigerant and the charge: R-404A, 180 kg, with its CO2e (706 t).
- Identification of the equipment: asset number, location, make/model.
- Dates and results of every leak check, not just the ones that found something.
- Location and nature of any leak found, and the date and description of the repair.
- Quantity of refrigerant charged and recovered at each visit. 'Gassed up' records nothing - the quantity is the single most important number in the log, because it quantifies the loss.
- Details of the leak detection system, its installation and its annual check.
- Name and certification details of the company and technician who did each piece of work.
Retention and access: at least 5 years, produced to the EPA on request. The duty sits with the operator - the depot - not only with the contractor, so the depot has to be able to show the file is complete.
Also missing: there is no record of the 2021 repair being verified, which should have been done within one month.
3. The leak is repaired on 3 March. What checks and records follow, and how does the servicing restriction on high-GWP gases affect this unit?
Read the worked answer
Immediately after repair
- A verification leak check within one month of the repair - with a pinhole on a condenser coil, pressure testing or a targeted electronic sweep, not just 'it holds gas'.
- Record the repair date, the leak location, the parts used, the quantity of gas charged, the verification result, and the name of the certified technician.
- Update the leak-check schedule; the three-monthly clock restarts from the verification check.
The high-GWP servicing restriction
- The unit's charge is 706 t CO2e, well above the 40 t CO2e threshold, and R-404A has a GWP of 3922, above 2500.
- Since 1 January 2020, using virgin HFCs with GWP of 2500 or more to service refrigeration equipment of 40 t CO2e or more has been prohibited.
- Until 1 January 2030, reclaimed or recycled R-404A may still be used, provided it is labelled as reclaimed/recycled and comes through a proper take-back route.
So the top-up must be with reclaimed gas, documented as such. Given the age, the leak history and the direction of the phase-down, the honest advice to the depot is to price a retrofit to a lower-GWP refrigerant or a replacement unit rather than plan around reclaimed R-404A indefinitely.