The number of compartments in a multi-zone body does not by itself show that temperatures stay separate in practice. Check closure of the walls and seals, supply and return airflow for each zone, evaporator capacity, sensor locations and door-opening profile together. The Thermo King Precedent manual treats cargo starting at the proper condition, clear air inlets and outlets, and tight centre-bulkhead seals as separate checks for each zone (manual, pp. 125-127). The airflow checks in the stacking and circulation guide apply separately to each zone.
How is the system separated?
Do not rank fixed or movable partitions only by flexibility. Check how the edges close against the floor, roof and side walls, whether air paths mix, and whether evaporator capacity matches the load and compartment volume in the drawing and installation file. A simple curtain does not automatically provide the function of a closed thermal zone.
The same displayed setpoint in two zones does not prove that the control arrangement is the same. The Thermo King Precedent manual gives an example where zones can be controlled individually with centre bulkheads in place, and a designated single-zone arrangement where bulkheads are removed and the host evaporator sensor controls both areas (manual, pp. 126-127). This distinction is scoped to that named unit; do not assume the same operation in every vehicle.
Two load profiles at once
If one zone carries frozen cargo and another chilled cargo, write down product acceptance conditions, load mass, door openings and waiting times together. Full, partial and empty-zone loads create different air and heat loads. The result of one operating scenario does not automatically transfer to another volume split or route.
Acceptance-test table
| Check | Condition to represent | Acceptance record |
|---|---|---|
| Partition and seal | Edge, floor and roof closure | Drawing, photo and leakage finding |
| Airflow and evaporator | Supply-return path, clearance and capacity | Unit setting, air path and measurement time |
| Sensors | Risk and representative points in each volume | Location plan, device ID and logging interval |
| Door profile | Independent access, sequential openings and waiting | Start and end minutes for each event |
| Load | Matched product, mass and placement | Dispatch scenario and decision |
Two devices do not establish that both compartments are fully represented. Proximity to supply air, a door or the load affects the reading. The measurement plan should identify the area each location represents, instrument verification and logging interval. A unit's return-air display and product temperature are different measurements.
Door profile also changes the test. If every delivery through the rear door opens both zones, a short stable-temperature record may not show the operational effect of independent access. Compare a side door, separate loading sequence and waiting between openings with the same cargo and ambient conditions. The fresh and frozen cargo in one vehicle guide provides a planning checklist.
For a small load, a passive insulated container can be an alternative; compare a qualified route, preparation, actual usable volume, handling and total cost of ownership together. Empty-container volume and preparation energy remain part of the calculation. A container is not equivalent to an active compartment in every condition.
Hypothetical example: a movable partition initially allocates space for four pallets at the front and two at the rear. Moving it to allow two at the front and four at the rear can change each evaporator's demand and airflow path as well as the volume split. Acceptance of the first layout does not automatically cover the second. Match permitted partition positions to the drawing and test scope.
For offer acceptance, request the partition drawing, seal and airflow information, evaporator capacity, sensor map, matched load profiles and door-event records in one file. Read them with the clearance and airflow checks in the refrigerated-body loading guide; compartment count alone is not proof of separation or performance.
