When looking for a refrigerated-van alternative, the first question is not only "how many hours?" A passive container spends the thermal capacity placed inside at loading; route suitability depends on the product band, starting load, coolant pack-out, lid openings and delays together. Do not declare a powered unit necessary or unnecessary before these inputs are verified.
Required route-card inputs
| Input | How to record it | Why it matters |
|---|---|---|
| Product condition | Accepted band, product/lot and measurement method | Prevents a single-temperature assumption |
| Starting load | Loading temperature and minimum-maximum mass/volume | Defines thermal load |
| Coolant pack-out | Plate, gel or other source; amount and placement | Makes protection capacity visible |
| Lid openings | Actual number and duration of container-lid openings, not vehicle stops | Separates each opening event |
| Ambient profile | Hot and cold scenario, sun, dock and warehouse conditions | Avoids one ambient value |
| Waiting and transfer | Loading, dock, transfer and delivery delays | Includes hidden time |
Take the product band from the label, specification or current procedure. Record minimum and maximum starting-load scenarios, not only an average; the same container can behave differently when lightly and fully loaded. Count container-lid openings rather than vehicle stops: a stop without opening is a different thermal event, while one stop can include several openings.
Define the starting event in the test and packing plan in advance. For a hypothetical time calculation, take a start at 08:00, final delivery at 14:00 and controlled put-away at 14:30: the interval to assess is 6 hours 30 minutes. This arithmetic does not prove temperature compliance; measurement records are also needed.
Record the product starting temperature, coolant model, preparation state and package layout. GEBHARDT's eutectic plate instructions require full solidification of specified plates; the table's 24 hours refers to freezing. When using the technical paper, keep that separate from transport duration. Gaps and dividers follow the selected packing configuration.
Pre-test arrangement
Use the real cargo or a technically justified representative load. Define product requirements, minimum and maximum loads, hot and cold ambient conditions, openings and delays beforehand. Record sensor positions, and do not label a sensor reading box air as a direct product-temperature measurement.
WHO’s annex on qualification for pharmaceutical temperature-controlled distribution considers load, ambient profile, pack-out and acceptance conditions together; its examples are within pharmaceutical qualification scope (pp. 18-19). When route, pack-out or equipment changes, the annex’s change approach calls for reassessment (p. 23). This is not automatic approval for food or every product.
What to do when evidence is missing. List the missing input, who will provide it and the required check. For example, a closed-container test does not establish performance for a route with repeated openings. That does not automatically make active refrigeration the only option; it identifies the passive candidate's unverified condition.
Add product, route, freezer and handling inputs to the Isotec TBX needs-analysis form. Review earlier evidence when preparation or the route changes; the cold-chain box duration guide explains how to read a duration report.
The 'up to 24 hours' statement on the GEBHARDT TBX page is a manufacturer's product claim. The stated duration alone does not establish performance for your cargo, ambient conditions, openings and delays. Ask for those conditions and the supporting test evidence together.
