Eutectics and insulation24 / 26

An EPS box has no fixed number of hours; wall thickness, outside temperature and the amount of ice give the time through a calculation. In the example box at 30 °C the ice is gone in about 14 hours.

The box average does not show contact risk. Place sensors against the actual product layout and assess the result.

A half-frozen pack and a warm box use up part of the calculated time before the shipment leaves. Conditioning is the performance step that needs no extra investment.

A foam box has no hours of its own; wall, coolant and outside air decide it. Worked example: a 46-litre EPP box with 31 mm walls stays cold for about 7 hours with 2 kg of ice at 25 °C.

Compare tested performance, usable volume and total cost under the same route and load.

Age alone is not a diagnosis: inspect panels, seals, holes, unit service, route and sensors as separate field trends.

Both work by phase change; for medicines the choice turns on the temperature at which the pack goes into the box. A pack straight from the freezer, or a frozen gel pack, can freeze a 2-8 °C product.

Separate plates per container from the total plate pool. Combine the thermal assessment for your load and route with return and freezing schedules.

Appearance, weight or one brief test cannot prove insulation. Confirm the model, inspect the lid and compare measurements under matched conditions.

Design summer and winter trials around your product, pack and route; one test duration does not fit every shipment.

Do not decide on a separate cabinet from trip count alone. Record model preparation time, freezer load and time between trips.

Test both transport options under the same load, route and lid-opening conditions; assume no universal duration or winner.

Once you know how many trips a container makes and how many never come back, the EPP or EPS question comes down to one calculation. Density, temperature limits and the breakeven loss rate are below.

Fixed external size means less internal space; fixed internal space means a larger footprint. Compare thermal performance under the same test separately.

The gap between hot food and outside air is roughly twice that of a chilled load. So the same thermobox holds hot food for less time, and the clock runs against 60 °C at the core of the food.

A catalogue figure is measured at 43 °C in an empty carrier up to a 10 °C limit, while the vaccine range is 2-8 °C. Field time depends on ambient heat, fill, lid openings and coolant preparation.