Beyond Basis Weight: What Is ECT, and Why Does It Determine Your Warehouse's Capacity?
In the packaging industry, paper weight (grammage) is no longer an indicator of quality. The ACIS Manual emphasizes the importance of a performance-based approach: the key metric isthe ECT (Edge Crush Test).
This test measures the vertical compression strength of a corrugated cardboard sample, and this value determines the box’s load-bearing capacity. A higher ECT value indicates better resistance to vertical compressive loads and greater stackability.
This figure is not an abstract value: it is directly correlated with the BCT (Box Compression Test), which measures the crush resistance of the entire finished package. While the ECT tests the material, the BCT assesses the empty box’s ability to withstand the weight of other packages stacked on top of it.
Designing based on ECT performance means ensuring the stability of packaging by using only the necessary amount of fiber, while embracing eco-design principles that reduce waste without compromising product safety.
How Relative Humidity Affects the Strength of Cardboard
Corrugated cardboard is a hygroscopic material, which means that its mechanical properties vary depending on environmental conditions. A key technical insight for every supply chain manager is the impact of humidity and the material’s inherent production tolerance:
- Tolerances: ECT and BCT values are subject to a manufacturing tolerance of ±10%. Knowing this information is vital for a logistics manager when determining safety factors.
- Relative humidity: An increase in relative humidity in the warehouse—from 50% to 60%—can reduce compressive strength by approximately 8%. In even more humid environments, the loss in strength can exceed 20%.
For this reason, a high-quality design must include an adequate safety factor that takes into account not only static weight but also vibrations during transport and climatic fluctuations. Using high-performance corrugated flutes (E, B, or C) and testing quality in the lab is the only way to avoidunderpackaging, the primary cause of returns and complaints.
Logistics Efficiency and PPWR Compliance: Less Air, More Stability
With the entry into force of the new European PPWR (Packaging and Packaging Waste Regulation), volume optimization has become a regulatory requirement: the maximum allowable void space will be 50%. This necessitates a shift to custom-fit packaging that eliminates internal voids.
Reducing empty space not only lowers shipping costs related to volumetric weight but also improves the box’s resistance to compression: a product that internally supports the box walls creates a structural synergy that increases the stability of the entire pallet. The goal of a proper technical analysis is to identify the perfect balance, avoiding both overpackaging (unnecessary material costs) and underpackaging (risk of breakage).
Designing packaging made from a single type of paper material not only facilitates recycling but also allows for the precise calculation—down to the millimeter—of the strength required for each specific logistics flow.
Turn packaging into a strategic asset
Would your current packaging pass a professional compression test? Understanding and demanding reliable technical data—such as ECT—is the first step toward modern, safe, and sustainable logistics. Scientifically designed packaging isn’t just a cost; it’s the primary ambassador of your company’s efficiency, capable of protecting the value of your product from the end of the production line through to final delivery.
Contact us to design packaging that’s optimized for warehouse logistics.
