Important Notes on Cardboard Ratings

When it comes to the strength ratings of boxes, the cardboard industry unfortunately has a couple of standards. After many years of only the Mullen Test which measures the bursting strength, the ECT (edge crush strength) was developed in the late 90’s. The ECT or stacking strength is a more meaningful measure of how a box will perform in the field.

The Spirited Shipper Kraft boxes utilize the ECT ratings on all our cardboard boxes. Don’t be fooled by high numbers like 200# Mullen ratings when comparing boxes as the ECT numbers are on a scale which doesn’t actually indicate a specific burst strength in pounds. For instance, it is widely accepted that a 32ECT rating is similar strength to a 200# rating. A higher number in either system will provide better protection. We recommend and utilize 44ECT and 48ECT rated cardboard for shipping glass bottles of wine, alcohol or any other liquid.