ISO 2234 Packaging - Completed, Filled Transport Packages and Unit Loads - Stacking Tests Using Static Loads

The International Organization for Standardization (ISO) standard "ISO 2234 Packaging - Completed, filled transport packages and unit loads - Stacking tests using static loads" describes three methods for performing stacking tests on a fully filled transport package or a unit load using static loads. Regardless of which method is used, the tests are performed to evaluate the performance of a package or unit load in terms of the durability or protection it provides to its contents when stacked.

It can be performed as a single test to investigate the effects of stacking (deformation, creep, collapse or fracture) or as part of a series of tests designed to measure the ability of a package or unit load to withstand a distribution system containing a stacking hazard.

The test can also be used to investigate performance under specific loading conditions, such as when the bottom package of a stack rests on an open-deck pallet, or when the overlapping load is supported on supports by a single-deck pallet resting on a container where the profile of the load is eccentric. For these purposes, one of three test methods may be more suitable than the others. A method for performing the stacking test using a compression tester is described in ISO 120481.

In a simple test, the test package is placed on a flat, horizontal surface and subjected to a uniformly distributed load from above using one of three methods. The load, atmospheric conditions, duration of exposure, and the environment to which the package will be exposed are determined in advance. If appropriate, the package's top-down or side-to-side deflection during the test can be measured.

The test pack should normally be filled with the intended contents. However, simulated or dummy contents may be used, provided their dimensions and physical properties are as close as possible to the intended contents. It is important to ensure that the test pack is dosed normally, as if ready for distribution. If simulated or dummy contents are used, it is important to ensure that the normal sealing method is still used.

The package should be conditioned in accordance with one of the conditions described in ISO 2233. Where the materials or package are critical to its application, testing should be conducted under atmospheric conditions used for conditioning, as close as possible to those used for conditioning. In other cases, testing should be conducted under atmospheric conditions as close as possible to those used for conditioning.

When performing the test, the package stack, or alternatively, the loading platform, is placed in the center of the test package, which is placed on a flat, horizontal surface. If Methods 2 and 3 are used, the masses comprising the load are placed on the loading platform without impact, ensuring that they are in full contact with the loading platform before being released. The masses should be evenly distributed across the portion of the loading platform surface in direct contact with the test package, ensuring that the center of gravity of the load is just above the center of the package's top surface. The distribution of the total load, including the loading platform mass, should be within 2 percent of the predetermined value. The distance from the load's center of gravity above the loading platform should not exceed 50 percent of the test package's height. The load is applied for the required time (typically 24 hours, depending on the material) or until collapse occurs. The load is then removed and the package inspected. Dimension measurements may be required at any time during the test. Appropriate profiled inserts can be placed above, below, or both above and below the test package, as required, to meet specific loading conditions.

In short, the ISO 2234 standard outlines three different test methods for assessing the performance of a full transport package or entire unit load when subjected to static stacking forces:

• Single stacking test: This method applies a single static load to simulate stacking conditions. It evaluates direct effects such as deformation, creep, collapse, or other types of damage under compression.
• Integrated (serial) stacking test: Performed as part of a series of tests, this method evaluates how well a package or unit load withstands stacking in the context of a complete distribution system containing stacking hazards.
• Special Condition Stacking Testing: This method is designed for specific or non-standard stacking scenarios. For example, when the subpack rests on an open-deck pallet or when the applied load is eccentric, such as when the pallet is supported only by its bearers. This approach helps evaluate performance under these atypical loading conditions.

The ISO 2234 standard is a critical part of quality assurance in industries where packaging must withstand stacking during storage or transport. Its primary purpose is to determine how well a filled package resists crushing or deformation when stacked. This helps manufacturers and logistics companies:

• Ensuring package integrity during long-term storage or transportation
• Preventing product damage caused by stacking pressure
• Optimizing material use by avoiding over-engineering of packaging
• Compliance with international shipping and safety standards

The ISO 2234 standard applies to complete and solid transport packaging made from any material (e.g., cardboard, plastic, wood). It does not cover unit loads (such as pallets or containers consisting of multiple packages) or individual product packaging.

ISO 2234 testing is widely applied in the following sectors:

• Food and drink
• Medicines
• Electronics
• Retail and e-commerce
• Production

The ISO 2234 standard outlines static pressure testing, which simulates the vertical load a package may be subjected to when other packages are stacked on top of it during storage or transport. Key considerations for these tests include:

• Preparation: A complete and full package is used as intended for shipment. The sample is prepared according to ISO 2233, which addresses the effects of temperature and humidity on the packaging.
• Test setup: A constant load is applied to the package using a compression tester. The weight simulates the load the package would experience at the bottom of a stack.
• Test duration: The load is applied for a specified period (typically 24 hours, but may vary depending on the intended stacking time under real-world conditions). The package is then inspected for deformation, collapse, or failure.
• Evaluation: The results help determine whether the packaging can safely support the intended stacking load.

The main benefits of ISO 2234 test methods are:

• Enhanced safety: Prevents packages from collapsing, carriers from being injured, or products from being damaged.
• Standardization: Provides a consistent method for comparing packaging strength across industries and regions.
• Sustainability: Promotes the efficient use of materials by determining the optimum packaging strength required for a given load.
• Cost reduction: Prevents over-packaging and reduces waste while maintaining protection.

Consequently, the ISO 2234 standard plays a vital role in the safe and efficient transportation of goods worldwide. By providing a standardized method for testing how packages perform under static stacking loads, it helps manufacturers ensure product safety, minimize waste, and meet international logistics requirements. For companies involved in packaging design, production, or distribution, compliance with this standard can be a valuable tool for improving performance and customer satisfaction.

Our organization, which has been serving for many years and meticulously following global developments in science and technology, employs a team of experienced professionals and a broad infrastructure to conduct testing, measurement, and analysis in a wide range of areas for businesses across all sectors. In this context, we also provide testing services in accordance with the ISO 2234 Packaging - Completed, filled transport packages and unit loads - Stacking tests using static loads standard.