Making sure your corrugated packaging is protecting your products correctly is a cornerstone in optimizing your facility's packaging operation. The box maker's certificate that is printed on corrugated boxes serves as an indicator of quality in the construction of the box. Often listed on the certificate are two values, one being Burst (Mullen) Test and the other being Edge Crush Test (ECT). However, not all boxes have both values stamped on them, so what’s the difference between the two? Both tests tell you the strength and durability of a box but are measured in different ways.
The Edge Crush Test measures the vertical compression stretch along the edge of a package. This test focuses on compression and stacking strength. This test was developed around 1990 to provide a better measure of how well boxes will hold up during palletizing and vertically stacking. ECT is often looked at by customers who are concerned about the max weight a box can stand during pallet shipments or warehouse stacking. The most common and universal boxes used today are 32 ECT.
The Mullen Test measures the bursting strength or the force required to burst a hole through the corrugated material. This measurement is calculated in pounds per square inch (PSI). Originally developed in 1887, the Mullen Test became a key regulation in the packaging industry. The test indicates how a package will perform when handled individually as many hands interact with the package giving more opportunity for damage from the outside. As the package moves from carrier to carrier its contents are more likely to be rattled around inside possibly causing a puncture. While it's not quite as common these days as ECT, many customers like the assurance of a Mullen tested box to protect heavier items for shipment.
Both Mullen and ECT tested boxes come in several options. The chart below shows where the two tests meet for similar strength.
To defend your product from being crushed during shipment, use Edge Crush Test certified boxes. If you're concerned about a package being punctured during shipment use Mullen Burst Test certified boxes. We always recommend reaching out to our packaging experts to make sure you are getting the most protection at the best cost. Contact us to make sure you're getting the most out of your corrugated packaging.