Mullen vs ECT
Mullen and ECT (Edge Crush Test) are the two primary standards used to measure the strength and quality of corrugated cardboard boxes, representing two different philosophies of durability.
Mullen Test (Bursting Strength)
The Mullen test measures the pressure required to puncture or burst the face of a corrugated board. It is the older of the two standards and focuses on how much force the box walls can withstand from the inside out or outside in.
How it is measured: A hydraulic device applies pressure to a circular area of the board until it ruptures. The result is expressed in pounds per square inch (e.g., 200#).
Best for: Shipping heavy, dense items or individual products that might shift or push against the sides of the box.
Key benefit: Superior protection against puncture, Rough handling, and "bulging" from heavy contents.
ECT (Edge Crush Test)
The Edge Crush Test measures the compressive strength of the board by applying pressure to the edge of the cardboard. Since most modern warehouse shipping involves stacking boxes on pallets, the industry has largely shifted toward ECT.
How it is measured: Pressure is applied vertically to the edge of a sample until it collapses. The result is measured in pounds per lineal inch (e.g., 32 ECT).
Best for: Palletized shipping and stacking where the primary concern is the box collapsing under the weight of other boxes.
Key benefit: Highly predictive of stacking strength and often more material-efficient (and cost-effective) for standard shipping needs.
Quick Comparison Summary
While a 200# Mullen box and a 32 ECT box are often considered roughly equivalent for general use, they are not identical. The Mullen test requires a higher weight of "linerboard" (the flat outer layers), which generally makes the box heavier and more resistant to tearing. In contrast, an ECT box focuses on the strength of the the wavy middle layer to provide vertical support.
For 95% of uses, ECT is the way to go. For E-Commerce purposes, Mullen should almost never be considered.
