Measurement of the edgewise compression strength of corrugated board has been going on for over 40 years. At the present time, only the TAPPI Test Method T 811 "Edgewise Compression Strength of Corrugated Fiberboards" is recognized as the standard for the edge crush test.
From the very beginning, it was realized that in most cases the test crushed the end surfaces. This was addressed in paragraph 7.1.2 "Whether or not a specimen exhibited a valid failure." Unfortunately there are no
guidelines to an "invalid failure."
The circular neckdown method is not new. It was presented in an article in Boxboard Containers in 1986 by David W. Bormett of the Forest Products Laboratory, Madison, Wisconsin.
The samples used in this test comparison were sampled and randomized very carefully to ensure that the samples were, for all intents and purposes, identical for the two methods.
