Knowledge / Selection and temperature ranges
Designing Reliable Shipping at +2 to +8 °C
Passive thermal packaging for +2 to +8 °C must prevent warming above +8 °C and cooling below +2 °C. The shipper, cooling elements, preparation and payload are tested together. The temperature marking on the packaging indicates its intended range; the test report shows the conditions under which it maintains that range.
Practical guidance
Check whether small containers and products at the edge of the shipper also remain between +2 and +8 °C.
THERMOCON thermal packaging in the laboratory. The complete configuration of shipper, cooling elements and defined payload is tested.
In this guide
- Define product quantity and initial temperature
- Water-based cooling elements or PCM +5?
- Why the same shipper can be too warm and too cold
- What happens if the packed shipper waits in a cold room?
- Select the correct summer or winter configuration
- Check these four points before the first shipment
- Temperature limit breached: preserve the records and have the goods assessed
Define product quantity and initial temperature
First check the product documentation to establish whether +2 to +8 °C is actually required. Also record the temperature at packing and the time until the goods enter storage at the recipient’s site.
Describe both individual small containers and full orders. The internal volume of the shipper alone says little about temperature behaviour: a light carton containing a lot of air responds differently from the same volume of liquid goods.
Water-based cooling elements or PCM +5?
Water-based elements can be suitable if the tested configuration maintains both temperature limits. Follow the prescribed preparation exactly. A frozen pack and a merely chilled pack affect the goods differently.
PCM with a melting range close to +5 °C absorbs heat during melting near the desired product range. Nevertheless, product temperature depends on the entire packaging system. If a PCM element is used too cold, it can initially overcool the goods as well.
Gel packs, foam bricks and rigid-shell packs describe the format. Water or a specialised PCM describes the medium inside the element. Compare both specifications; similar-looking packs are not automatically interchangeable. The cold shock troubleshooting guide explains how to investigate excessive cooling.
Why the same shipper can be too warm and too cold
Heat enters the shipper through walls, joints and the lid, and is absorbed by the cooling elements. This creates temperature differences. A container directly beside a frozen element may become too cold while a more distant location is already above +8 °C. Additional coolant packs do not necessarily correct an unfavourable heat distribution.
Small fill quantities can respond faster than larger liquid containers. The speed also depends on surface area, outer packaging and position. Substitute products used in testing must represent these properties adequately; equal weight alone is insufficient.
Use the designated product compartment and all separating layers. Additional filling material can change air paths and contact areas. A shipper lying on its side should also be tested if this orientation is expected during shipping.
What happens if the packed shipper waits in a cold room?
Example: A shipper designed for warm ambient temperatures contains frozen water-based packs. After packing, it waits in a cold room. Less heat enters from outside, while the frozen packs can continue removing heat from the goods. This can increase the risk of excessive cooling.
The correct waiting area therefore depends on the tested packaging configuration. For some designs, refrigerated intermediate storage is intended and beneficial. For others, it changes the conditions for which the packout was tested.
Define the storage location, temperature and maximum waiting time between packing and collection. Test this stage together with the subsequent transport. The effect on the packed shipper cannot be inferred from the storage room’s set temperature alone.
Select the correct summer or winter configuration
In warm surroundings, the system must absorb heat; in cold surroundings, it must protect the goods from further cooling. Passing a summer test therefore does not establish sufficient winter protection.
Check whether different seasonal configurations or a demonstrated year-round packout are specified. The packing instructions must identify which variant to use. The packing process guide provides advice on identification and staging.
Check these four points before the first shipment
- Components: Do the shipper, coolant pack type, number, arrangement and separating layers match the test report?
- Payload: Are product quantity and initial temperature within the tested limits?
- Preparation: Do the packs reach the prescribed state with the available equipment and its usual loading?
- Transport: Are summer, winter, waiting times and the entire duration until storage covered?
Look for measurement locations close to cooling elements and at other critical product positions in the test report. An average can conceal local excessive cooling.
Products requiring +15 to +25 °C have different preparation requirements. These are explained in the article on CRT shipping.
Temperature limit breached: preserve the records and have the goods assessed
A return to the +2 to +8 °C range does not demonstrate that the goods are unaffected. Preserve the complete temperature history, timings and packing data. The responsible quality assurance team assesses the excursion using the affected products and their stability data; usability cannot be determined from the packaging alone.
Sources
- EU GDP Guidelines 2013/C 343/01, Chapter 9. Chapter 9: transport, packaging and special storage conditions for medicinal products for human use.
Sources checked on 12 September 2026.
Select packaging for +2 to +8 °C
To select a system, we need the smallest and largest payload, the temperature at packing and the planned waiting times before collection.