The Supermarket 'Gas Log' With Three Words On It
You take over maintenance of a small supermarket with three systems: Unit A, a dairy case on R-134a with a nameplate charge of 8.0 kg; Unit B, a medium-temperature pack on R-407C with 22 kg; Unit C, a hermetically sealed R-410A split serving the office, 4.5 kg. The handover folder contains a single sheet headed 'gas log' with three entries reading 'checked, OK'. There are no dates, no technician names and no record of a 3 kg R-134a top-up invoiced last year. The store manager asks which units need checking and how often, and says he will bin the old paperwork because it is out of date.
1. For each of the three units, state whether periodic leak checks are required and at what interval. Show your figures.
Read the worked answer
Unit A - R-134a, 8.0 kg: 8.0 × 1430 = 11,440 kg CO2e = 11.4 t → 5–50 t band → every 12 months (24 with a leak detection system).
Unit B - R-407C, 22 kg: 22 × 1774 = 39,028 kg CO2e = 39.0 t → still in the 5–50 t band → every 12 months. It is close to the 50 t line but does not cross it; a 29 kg charge would.
Unit C - R-410A, 4.5 kg, hermetically sealed: 4.5 × 2088 = 9,396 kg CO2e = 9.4 t. Hermetically sealed equipment below 10 t CO2e is exempt from periodic leak checks, so no scheduled check is required - it is only 0.6 t under the threshold, so any increase in charge on that unit would change the answer.
Note that Unit C is exempt from checking but is not exempt from record keeping, because it is at or above 5 t CO2e.
2. What records must the operator hold, and can the manager simply discard the old folder?
Read the worked answer
No, the folder cannot be binned - records must be kept for at least 5 years, and a three-word 'checked, OK' entry is not a record.
For each unit at or above 5 t CO2e the operator needs:
- Type and quantity of gas installed
- Quantity added at each intervention and quantity recovered
- Date and result of each leak check
- Name of the certified company and technician certificate number
- Where a leak detection system is fitted, its inspection records
Which is why the missing 3 kg R-134a top-up matters: the label says 8.0 kg, so an undocumented addition means nobody can say what is actually in Unit A, or whether the leak was ever found. Undocumented charge also undermines the CO2e figure used to determine the leak-check frequency. Your first job is to reconstruct what you can, verify the charge, and start a compliant log with dated, signed entries.
3. What labelling should be on these units, and what would you do about the missing top-up?
Read the worked answer
Each unit should carry a label showing the refrigerant designation (and blend composition for R-407C), the charge in kg and in t CO2e, and the GWP. Unit C, being hermetically sealed and factory-charged, still needs the label. Labels must be legible, fitted at commissioning, and updated whenever the charge or the refrigerant changes.
On the missing 3 kg:
- Do not accept the invoiced figure as a record; verify by weighing in and checking against the nameplate.
- If the system has been topped up, the leak was never fixed - leak-check it, then repair and carry out the one-month confirmation check.
- Record the addition you make (or the verified installed charge) with date, quantity and certificate number so the tCO2e on the label and the leak-check interval are both defensible.
- Raise the record-keeping failure with the operator in writing; it is their legal obligation, not the contractor's.