The warmest reading is almost never the problem.
Open the doors at a delivery in a Riyadh August and the probe will record a number that looks alarming. Meanwhile a unit quietly failing overnight never gets near it, and that is the load you lose.
Three excursions, one week
Same vehicle type, same -18°C setpoint. Switch between them — the verdicts do not follow the peaks.
- Peak
- -13.4°C
- warmest reading
- Above limit
- 102 min
- over -15°C
- Degree-minutes
- 105
- how far, how long
- Doors
- Shut throughout
- warming unexplained
Load compromised
Reefer unit cut out overnight in the yard. Doors never opened.
Load rejected at the customer's gate. The record is why the claim went to the reefer contract, not to us.
Delivery stop reached -8.2°C and cost nothing. Compressor stall never got past -13.4°C and lost the load. Ranked on peak temperature the two are the wrong way round, which is why peak temperature is not what the verdict is built on.
Four things decide it, not one
No single number adjudicates an excursion, and any vendor offering one is selling you a threshold you will end up ignoring.
Dock wait carries the highest degree-minutes of the three and is still only an advisory, because the doors were open and the unit pulled back down normally. The same curve with the doors shut is a fault.
- Time above limit
- Under 15 minutes is a door opening. Over an hour is a failure, whatever the peak was.
- Door correlation
- Warming while the doors are open is physics. The same curve with the doors shut is a fault.
- Recovery rate
- A unit that pulls back down at the normal rate is working. One that crawls back is the next failure.
- Degree-minutes
- How far above the limit, for how long, summed. Spoilage does not care about the highest reading.
| Excursion | Peak | Minutes above -15°C | Degree-minutes | Doors | Verdict |
|---|---|---|---|---|---|
| Delivery stop | -8.2°C | 20 | 66 | Open | Within tolerance |
| Compressor stall | -13.4°C | 102 | 105 | Shut | Load compromised |
| Dock wait | -10.6°C | 44 | 130 | Open | Advisory |
A reefer is not one temperature
Multi-temperature trailers run three setpoints behind two bulkheads, and a compartment can fail while the one next to it is perfect. One probe on the return air tells you almost nothing about either.
Probes go where the load is, not where the wiring is convenient — two per frozen and chilled compartment, so a single failed sensor is visible as a disagreement rather than quietly becoming the record.
Compartment 1
-18°CFrozen
- Tolerance
- ±3°C
- Probes
- 2
Compartment 2
+ 2°CChilled
- Tolerance
- ±2°C
- Probes
- 2
Compartment 3
+ 18°CAmbient
- Tolerance
- ±6°C
- Probes
- 1
The record is the product
Nobody buys temperature monitoring to look at charts. They buy it so that when a receiving department refuses a pallet, there is something to put in front of them the same afternoon.
How a disputed delivery becomes a file- Every reading, not a summary
- One sample every 2 minutes per probe, kept for six years. A customer asking about a delivery in 2029 gets the actual trace, not an average.
- Gaps are recorded as gaps
- If a probe drops out, the record says so at that timestamp. A trace with an unexplained flat section is worth less than one that admits what it does not know.
- Door state alongside
- Because every reasonable question about a rise starts with whether the doors were open.
- Signed export
- The window either side of a delivery as one file, in the format receiving departments and SFDA submissions expect.
A rejected pallet of frozen goods costs more than a year of monitoring on that vehicle.
Long enough to outlast the contract the dispute will be about.
Fine enough that a fifteen-minute door opening has seven points in it, not one.
The rest of the platform
Live tracking
Position, speed and ignition every ten seconds.
Routing and dispatch
Plan the day, send it to the driver's phone.
Asset and trailer tracking
Trailers, generators, plant and containers.
AI dashcam
Road and cabin, clipped to the event.
Driver behaviour
Scored per driver and per trip.
Incident centre
Footage, telemetry and witnesses in one file.