01The difference between a mark and a record
The IPPC mark burned into a stringer says that a registered facility performed a compliant treatment on that pallet. It is a declaration. It is not evidence.
Evidence is the charge record: which chamber, which day, how long, what the probes read, who ran it and how many units were in it. In routine trade nobody asks. In an investigation, a dispute, or a customer audit, it is the only thing that matters.
02What a compliant charge record contains
| Field | Why it exists |
|---|---|
| Charge number | Ties a specific batch of wood to a specific treatment event |
| Date and start/end times | Establishes the treatment window |
| Probe count and placement | Demonstrates the coldest point was measured, not the easiest |
| Continuous temperature trace | Proves 56°C was held for 30 uninterrupted minutes |
| Ramp and cool-down times | Shows the full cycle, not just the compliant window |
| Operator identity | Accountability, and it changes behaviour |
| Unit count and description | Ties the record to a quantity that can be reconciled |
| Facility registration number | Links the record to the mark applied |
03Where charges actually fail
- Solid stacking. Pallets stacked without airflow channels heat unevenly. The centre never reaches 56°C and the probes, if placed correctly, say so.
- Probe placement in a warm spot. Putting the thermocouple in an accessible outer pallet produces a compliant-looking trace and an untreated core.
- Opening the door mid-charge. Probe temperatures drop within seconds and the 30-minute clock restarts. Operators learn this once.
- Green or very wet wood. Water absorbs enormous energy. A charge of soaked pallets can take twice as long to reach temperature.
- Overloading the chamber. More mass than the burner can bring up in a reasonable time.
I distrust any treatment record showing a suspiciously round total time. Real charges have ragged ramp profiles, and the ones that had to restart the clock show it.
04How long to keep them
We retain seven years. That is longer than most requirements and it is deliberate: a phytosanitary investigation can reach back a long way, and the marginal cost of storing a data file is nothing against the cost of not having it.
If you treat in-house, keep the traces themselves rather than a summary. A summary is somebody's assertion about the trace; the trace is the trace. And keep them somewhere that survives a change of chamber supplier — records stranded in a decommissioned controller are records you do not have.
05The scenario this is for
A container is stopped. Live insects, or a suspect mark, or a routine inspection that escalated. The agency wants to know whether the treatment claimed by the mark actually happened.
If the answer is a charge number, a date and a probe trace showing 32 continuous minutes above 56°C, the conversation usually ends there. If the answer is that the supplier says they treated it, the outcomes range from on-arrival fumigation at $400 to $2,500 per container, through re-export at your cost, to destruction of the packaging and occasionally the goods.
This is why we treat in our own chambers rather than subcontracting it. Not because subcontractors are unreliable, but because the record needs to be ours to produce. More on how we run charges is on the heat treatment service page.
