Cardboard Box Testing - Understanding BCT & ECT
- , by EJ Sinclair
- 5 min reading time

If you rely on shipping and packaging to transport your products, choosing the right cardboard box is essential so that your products arrive at their destination safely and in good condition. Understanding the difference between the Box Compression Test (BCT) and the Edge Crush Test (ECT) can help you make more informed decisions when selecting cardboard boxes.
What is BCT or Box Compression Test?
The Box Compression Test (BCT) is a test used to measure the maximum load a box can withstand before it collapses. The BCT is a widely accepted method for measuring the strength of corrugated cardboard boxes commonly used in the packaging industry. During the test, the box is placed on a compression machine and pressure is gradually applied until the box collapses. It can also be used to check that a box can withstand a predetermined force.
The force is measured in pounds per square inch (PSI). The BCT is typically used for larger boxes that are designed to hold heavy or bulky items. The BCT measures the vertical compression strength of a box. BCT is an important measure of a box's strength, as it simulates the weight and pressure that the box may encounter during shipping and handling.
What is ECT or Edge Crush Test?
The Edge Crush Test (ECT) on the other hand measures the strength of the cardboard material itself, rather than the box as a whole. This test measures the amount of force needed to crush a small section of the box's edge. The ECT is conducted by placing a small section of the edge between two flat plates and applying force until the section crushes or collapses.
The force is measured in pounds per inch (PPI). The ECT is typically used for smaller boxes or packaging materials that are designed to hold lighter or smaller items. The ECT shows the strength of the cardboard material, which is an essential factor in determining the overall strength and durability of the box.
Factors That Contribute to the Strength and Quality of a Cardboard Box
Both the BCT and ECT are important for determining the quality of a cardboard box. A box that fails either test indicates that it is not strong enough to withstand the weight and pressure it may encounter during shipping or handling. A good quality cardboard box should be able to pass both tests.
There are a few factors that contribute to the strength and quality of a cardboard box, including:
- The thickness of the cardboard material and the type of flute – thicker cardboard and boxes that are well-designed generally provide more strength and durability.
- The quality of the cardboard material – high-quality cardboard made from new fibres tends to be stronger than recycled cardboard.
Other factors can also affect its strength and durability, including the size and shape of the box, and the adhesive used to join the layers of the cardboard.
How Does Flute Type Affect Cardboard Box Quality?
Corrugated cardboard is made up of three layers: an outer layer, an inner layer, and a corrugated medium that runs between the two liners. The corrugated medium typically comprises a series of parallel ridges and valleys, which creates a series of flutes.
The flute size and shape can vary, and different flutes offer different levels of strength and cushioning. The choice of flute depends on the specific needs of the product being shipped and the desired level of protection.
For example, if you are shipping fragile items, you may need to choose a box with additional layers or a thicker flute for cushioning so that your products are kept safe during transit. On the other hand, a box with a flute that is thinner and lighter makes it easier to handle and store.
Balancing the Benefits of New and Recycled Cardboard
Although high-quality cardboard made from new fibres tends to be stronger than recycled cardboard, it is important to also consider sustainability. Choosing boxes made from sustainable and recycled materials is not only better for the environment but is also increasingly important for consumers who like environmentally responsible companies.
When cardboard is recycled, it goes through a process of being pulped and then re-formed into new sheets of cardboard. During this process, the cardboard fibres can become shorter and weaker, which can impact the overall strength and durability of the final product.
The quality of the recycled cardboard also depends on the source of the recycled material. Clean, unprinted boxes produce stronger recycled cardboard. However, the end product may be weaker if the recycled fibres come from lower-quality sources, such as mixed paper or contaminated cardboard.
Boxes that pass the compression and edge crush tests are a good indicator of quality. At The Packaging Club, our 0201 cardboard boxes are made from high quality corrugated cardboard and they perform above industry standards – they are excellent value for money too!
In summary
Understanding the Box Compression Test (BCT) and Edge Crush Test (ECT) can help you make more informed decisions when selecting cardboard boxes. The BCT and ECT testing methodologies are important for determining the strength and quality of cardboard boxes.
A good quality cardboard box should be able to pass both tests. Factors such as the thickness and quality of the cardboard material, as well as the construction of the box, contribute to its strength and durability. The type of box that is best for you depends on your specific packaging needs.
Consider the fragility and size of your products, as well as the shipping method and destination. Choosing the right cardboard box will help your products arrive at their destination safely and in good condition.