A call that comes often in July: the driver rings, the refrigeration unit has gone quiet, the cab display reads +9 °C. The person at the depot has to choose between recalling the vehicle and letting it carry on. Both cost money, and the display cannot say which costs less, because it usually reads return air. The Thermo King manual also describes the check through return air and asks for the load temperature to be checked separately (pp. 125-129). The core temperature of the product needs a measuring point, an instrument and a time record.
The first half hour
- Secure vehicle and people first; stop somewhere safe to record and call. Do not open the doors unnecessarily, since every opening spends the cold that is left.
- Write down the failure time, location, setpoint, display value, alarm and last door opening, and preserve the existing temperature data.
- Have the product temperature measured by a defined method, and record the point, the instrument and the time.
- Inform the operations owner and the consignee, with the records.
Work on the electrical, fuel or refrigerant systems belongs to service. According to the manual, if the compartment temperature does not return to range on two consecutive 30-minute checks, the unit is stopped, service is contacted and every step needed to protect the load is taken. The same manual states that the unit only maintains the loading temperature and does not pull a warm load down (p. 125).
Routing: the point the plan names
The contingency plan should state which receiving or transfer point can take this load, who decides and who measures. Capacity, product regime, operating status and safe access are confirmed in advance. In FAO's food HACCP guidance, Step 9 asks for planned monitoring and records, and Step 10 treats evaluating the affected product, bringing the process back under control and recording the corrective action as separate jobs.
If the cold is inside the container
In a GEBHARDT Isotec TBX the regime is carried by eutectic plates frozen at the depot, not by a unit on the vehicle; if the vehicle breaks down, the regime stays in the container. The plates melt at -3, -14, -18 and -21 °C, the GEBHARDT TBX document gives up to 24 hours of cold-chain security, and an optional external thermometer can be fitted to the door, so the driver reads the internal air temperature without opening it and writes it down with the time. This works only if the plates were frozen sufficiently before loading, and it does not bring back a load that has warmed. Models: Isotec TBX.
| Record | Why it matters |
|---|---|
| Time, location, setpoint, display and alarm | Event timeline |
| Product temperature, measuring point and instrument | Load assessment |
| Last door opening and estimated arrival | Heat exposure comparison |
| Decision owner, receiving point and action | Traceable corrective action |
Keep the records together using the cold-chain evidence approach.
