7 Ways to Test Shipping Box Strength

Written by UPrinting    ●    Updated on October 11, 2023

When we say that our shipping boxes are durable and are made from high-quality corrugated cardboard, we aren’t just tooting our own horn. There are numerous standardized tests that are employed to test the strength of cardboard boxes. These help determine the box's ability to withstand various stresses and provide information about its structural integrity. In this article, we go over seven of the most common strength tests employed.

1. Burst Strength Test

Also known as the Mullen Burst Test, this measures the ability of a shipping box to withstand pressure and resist bursting when subjected to force. In this test, a hydraulic or pneumatic device applies pressure to a small area of the box until it bursts. The bursting strength is recorded as the maximum pressure the box can withstand. This test is important for assessing the box's resistance to punctures and compression forces during transportation.

This test is measured in pounds per square inch (lb/in) and are reported as a box rating. You’ll see this written as 100#, which means that the material can withstand 100 pounds per square inch force applied before bursting.

2. Edge Crush Test (ECT)

The edge crush test checks the stacking strength of corrugated shipping boxes. It measures the force required to crush the edges of a box vertically. How it’s done is a sample of the box is placed between two rigid plates, and force is applied until the box collapses. The ECT value is measured in pounds per inch (lb/in) and is an indicator of the box's resistance to vertical compression. Higher ECT values indicate greater stacking strength and durability.

3. Box Compression Test (BCT)

The box compression test, also known as the container compression test, measures the overall strength and load-bearing capacity of a shipping box. It involves subjecting a box to gradually increasing compressive forces until it deforms or collapses. The BCT value is measured in pounds and indicates the maximum weight a box can withstand without failing. This test is crucial for determining if a box can support the weight of other boxes during storage or transportation.

4. Stacking Test

The stacking test evaluates the ability of shipping boxes to withstand vertical stacking pressure. It simulates real-world conditions by stacking boxes on top of each other to assess their resistance to compression and deformation. The boxes are loaded with weights according to specific protocols, and their ability to maintain their shape and structural integrity is observed. This test helps determine the suitability and strength of the boxes for stacking during storage and transportation.

5. Drop Test

The drop test checks the ability of shipping boxes to protect their contents from impact and shock during handling and transit. Boxes are subjected to controlled drops from predetermined heights onto various surfaces (e.g., plywood, concrete) to simulate different impact scenarios. The drop test assesses the box's ability to withstand impact without damage, such as structural failure or product breakage. It helps determine if a box provides sufficient protection for fragile or valuable items.

6. Vibration Test

The vibration test evaluates the ability of shipping boxes to withstand vibrations that occur during transportation, particularly for long distances or rough terrains. The box is subjected to specific frequencies and levels of vibrations to simulate real-world conditions. This test helps identify potential weaknesses in the box's design or construction that may lead to product damage or failure due to excessive vibrations.

7. Packaging Moisture Level Test

The packaging moisture level test determines the moisture content within the shipping box. Excessive moisture can weaken the box and compromise its strength and integrity. Moisture content is measured using specialized instruments or by weighing the box before and after drying it in controlled conditions. By maintaining appropriate moisture levels, the test ensures that the box remains structurally sound and resistant to damage caused by humidity, rain, or other environmental factors.

When it comes to shipping, you have to have the peace of mind that your products are safe, whether they’re in storage or in transit. These tests, conducted according to industry standards, such as those set by organizations like the International Safe Transit Association (ISTA) or the American Society for Testing and Materials (ASTM), are all done to ensure consistent and reliable measurement of cardboard box strength.

With UPrinting, you can rest assured that all of our custom boxes, from large corrugated shipping boxes to mailer boxes for e-commerce, are thoroughly tested to meet industry standards and provide optimal protection for your products.