Blog - Laboratory: How a Climate Chamber Puts Packaging Through Its Paces for Days on End

How Climate Testing Works

Climate Testing: From the Refrigerator to the Climate Chamber

We all have a refrigerator at home to keep food fresh for longer. Just as commonplace is an oven for heating and cooking meals. The effects of temperature are something we encounter every day, often without giving them much thought.
A refrigerator typically operates at around 4 to 8°C (39 to 46°F), while an oven may be heated to 180°C (356°F) or more. Packaging is not normally exposed to such temperatures in everyday use. During storage and transportation, however, it is often subjected to heat, cold, and humidity, all of which can affect its performance and properties.
This is exactly what climate testing in the laboratory is designed to simulate.

What Happens Inside a Climate Chamber?

A refrigerator generally maintains a temperature just above freezing. In a climate chamber, on the other hand, both temperature and humidity can be precisely controlled.
Modern climate chambers can create not only constant environmental conditions but also temperature cycles. For example, alternating cold and warm environments can be simulated to reflect conditions encountered during storage, handling, and transportation.
Depending on the test objective, individual packages, shipping cartons, or even complete palletized loads can be examined.

Which Temperatures Are Tested?

The required temperatures depend on the applicable test standard and the intended use of the product. Typical ranges include:

Standard	Minimum	Maximum
ISTA	-29 °C	+60 °C
ASTM D4169 (typisch)	approx. -30°C	approx. +60°C
MIL-STD-810	-51 °C	+71 °C

These conditions make it possible to simulate many of the environments that packaging may encounter during transportation and storage around the world.
While temperatures only slightly below freezing may already feel uncomfortable to people, packaging and products may need to withstand temperatures far below -20°C or above +50°C. Climate chambers allow these conditions to be accurately reproduced and monitored.

Extreme Temperatures Are Not Uncommon

Temperatures of -30°C or +60°C may seem unrealistic at first glance. In reality, such conditions can occur throughout a distribution chain.

A shipment may spend extended periods outdoors during winter handling operations or be exposed to high temperatures inside containers, trailers, or warehouses during summer. International transportation routes often involve movement through multiple climate zones, where both temperature and humidity can vary significantly.

Climate testing makes it possible to reproduce these conditions under controlled laboratory settings.

Why Is Humidity Considered Alongside Temperature?

Anyone who wears glasses has experienced lenses fogging up when moving from a cold outdoor environment into a warm room. Packaging materials respond to humidity in a similar way.

Materials such as paper, corrugated board, and wood-based products absorb and release moisture depending on their surroundings. This can lead to changes in weight, strength, and dimensions.

For this reason, climate testing is frequently conducted not only at specific temperatures but also under controlled humidity conditions.

Why Does Climate Testing Often Last 72 Hours?

Many people assume that packaging quickly reaches the same temperature as the surrounding air. In reality, this process often takes much longer.

The same principle applies in everyday life. A bottle of water does not become cold immediately after being placed in a refrigerator, and a casserole remains hot long after it has been removed from an oven.

Packaging behaves similarly. Large shipping cartons and especially palletized loads require considerable time for temperature and humidity to penetrate to the center. A stretch-wrapped pallet may have already reached the desired external conditions while the core remains at a completely different temperature and moisture level.

As a result, climate conditioning is often carried out for 72 hours or longer to ensure that the specified conditions reach the entire test specimen.

Why Is Climate Testing Important?

Many packaging materials are sensitive to changes in temperature and humidity.

Corrugated board and other paper-based materials can lose strength when exposed to high humidity. Corrugated boxes that perform well under dry conditions may behave very differently in warm and humid environments.

Plastics generally respond more strongly to temperature. At elevated temperatures, many plastics become softer and more flexible, while low temperatures can make them brittle and more susceptible to cracking under load.

Adhesives, foams, cushioning materials, and other packaging components may also be affected by climatic influences.

Climate Testing as Preparation for Further Testing

In many test programs, climate conditioning is not the final step. Test samples are often first conditioned in a climate chamber and then subjected to additional evaluations.

For example, a package may be conditioned under high humidity for several days before being tested in a compression test. This makes it possible to assess how environmental exposure affects performance under transportation loads.

The key question is not only whether a package can withstand heat, cold, or humidity, but also how it performs afterward when exposed to the stresses of handling and transport.

Conclusion

Temperature and humidity influence packaging far more than many people realize. While we use refrigerators and ovens in everyday life to cool or heat food, climate chambers create controlled environmental conditions to study how packaging materials and products respond to their surroundings.

Climate testing helps reveal material changes and enables testing under reproducible conditions. For humidity-sensitive materials such as corrugated board and temperature-sensitive materials such as plastics, climate testing is therefore an essential part of packaging performance evaluation.

Would you like to find out how temperature and humidity affect your packaging?
BFSV can help you select appropriate climate tests as well as additional packaging performance tests.