When looking through our cardboard shipping box order forms and featured inventory list, you will see numbers under the column “Test”. What does this mean? The Burst Test (aka Mullen Test) measures the force, expressed in pounds per square inch, required to rupture or burst the side of a cardboard box. This indicates the ability of the box to withstand external or internal forces and how the box will contain its contents during rough handling. A box with burst strength of 125 lbs per sq. inch indicates that the cardboard used to make the box can withstand 125 lbs of pressure per square inch.

Edge Crush Test (ECT) measures the stacking strength of corrugated cardboard boxes. Compression strength is defined by the amount of force, in pounds per square inch that is needed to crush cardboard by standing it on its edge. For example, a box with an ECT rating of 32 lbs per square inch indicates that the cardboard used in the box, standing on edge, can withstand a force of 32 lbs per square inch before crushing.

Single-wall Corrugated Board, used in standard boxes