Corrugated Box Strength Test – Bursting Strength Explained

How do you know if a corrugated box is strong enough for your product? Strength testing provides objective, measurable answers. The three primary tests – Bursting Strength Test (BST), Edge Crush Test (ECT), and Box Compression Test (BCT) – each measure different aspects of box performance. Understanding these tests helps you specify the right box strength and avoid both over-engineering (wasting money) and under-engineering (risking product damage).

The bursting strength test measures the maximum pressure a corrugated board can withstand before rupturing. A rubber diaphragm is pressed against the board with increasing hydraulic pressure until the board bursts. The result is measured in kg/cm². This test is most relevant for protection against puncture and concentrated impacts – like a forklift tine or sharp corner pressing against the box.

The edge crush test measures the resistance of corrugated board to crushing forces applied along the edge. A sample is placed vertically and compressed until it collapses. This test directly predicts stacking strength – how many boxes can be stacked on top of each other without the bottom box collapsing. ECT is increasingly preferred over BST for specifying box strength.

The box compression test is the ultimate performance test – it measures the maximum weight a complete, assembled box can support before collapsing. Unlike BST and ECT which test the board material, BCT tests the entire box including its dimensions, flap design, and closure method. This is the most practical test for warehouse and shipping applications.

Europack tests every batch of corrugated boxes against the specified strength parameters. Our quality control lab performs BST, ECT, and moisture content testing to ensure consistent performance. Test certificates are available on request for quality-conscious clients.