Vehicle qualification and thermal mapping

What exactly is vehicle qualification?

It is the documented and experimental exercise proving that one specific trailer — not a model, not the fleet in general — can hold the declared temperature range under real operating conditions. GDP guidelines do not prescribe the test step by step, but they do require suitable equipment and evidence; the method the industry accepts is the one used for equipment qualification under Annex 15 of GMP: installation, operation and performance under working conditions.

What does a thermal mapping measure?

It measures temperature at many points of the box simultaneously, over hours, to find where it behaves worst. A trailer does not have one temperature: it has a temperature distribution, and the extremes are always far from the control probe.

Multiple loggers

Distributed through the load volume — floor, roof, corners, doors and bulkhead — to cover the whole box, not one plane.

Worst case, hot and cold

The test runs under the least favourable conditions, which is when the equipment has to prove it copes.

Doors included

The door area is the most frequently recurring critical point of any mapping, and it is exactly where the last pallet loaded ends up.

Outcome

A report identifying the hot and cold spots, which is what then justifies where the control probe sits and which zones are avoided.

Why does probe placement matter?

Because the record handed to the customer is the probe’s, and if the probe sits in the most favourable spot the record says everything went well while product in the corner was out of range. Mapping is what prevents that self-deception: once the worst point is known, the control probe goes where the reading is representative, not where it is convenient to fit.

What else is part of qualification?

1. Probe verification against a reference, so the reading is reliable and not an estimate.
2. Continuous recording with two independent probes throughout the service, not spot checks.
3. Written procedures for pre-cooling, loading, incidents and delivery, within the ISO 9001:2015 system.
4. Preventive maintenance of the cooling unit with its documented history.
5. Recorded training for the driver who will handle the product.

How often is it repeated?

Periodically, and additionally whenever something happens that could change how the equipment behaves: a significant repair to the cooling unit, work on the insulation, or a new trailer joining the fleet. An old mapping of a trailer that has since been repaired proves nothing about its current state, and that is precisely what an auditor looks at.

Frequently asked questions