Converting Stacking Strength to Burst Strength

Krista asks:

We had a compression test performed on a box, then on the box with our partition inside of it. How do we convert these results from stacking strength to bursting strength? We are trying to figure out what would be the ECT equivalent of our partitions.

I don’t know of any formula for directly converting compression, or stacking, strength to burst strength. The Georgia boy in me would say it’s kind of like comparing peaches and nectarines. Though related, they are really two different measurements.

The best way to determine the exact ECT value of the partition is to have it tested separately.

So you have the compression strength of the box and the combined compression strength of the box and partition. Subtracting the box compression strength from the combined compression strength will give you, roughly, the compression strength of the partition ‘in use’. However, the box flaps and panels will contribute, to some extent, to the partition strength and vice versa. So, one would believe that the components tested together may provide a somewhat higher (stronger) result than the total of the box and partition tested separately.

If you choose to test the compression of the partition by itself, I would be interested in finding out how the individual strength of the box and partition compare to the combined strength.

If anyone out there has already done such a comparison and would like to share your findings, we would be very interested in hearing what you found.

-Ralph

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5 Responses to “Converting Stacking Strength to Burst Strength”

  1. Jeff Says:

    We are a sheet plant that tests incoming material on a regular basis. One of the tests we perform is an ECT test regardless of whether the material is ECT or Mullen grade. Through the course of our testing we have found that the 150C material we receive averages 41.0 ECT compared to our 32 ECT which averages 40.1 ECT when we receive it. Also, our 200C averages 47.7 ECT compared to our 44 ECT which averages 48.0 ECT when we receive it. The only other Mullen grade we test on a regular basis is 275C and it averages 62.6 ECT when we receive it.

    By no means is this a scientific calculation that directly converts from one to the other but it gives a little insight as to how they relate to one another for us. Due to diferences in liner combinations and various other factors, you may end up with different results.

  2. Ralph Says:

    Thanks for the input Jeff. This is good information.

  3. Len Oppenheimer Says:

    Ralph, I’m assuming the request is being made because of crushing while stacked and the bursting due to somthing like handel tearing during lifting. in the end whats needed is to get max strength from minimum board material on both counts. Krista may be interested in these partitions found at http://www.strongholdpartitionsets.com which we have developed for this very reason. if you would share it with her im sure it would be appreciated.

  4. Ralph Says:

    Len – More good information. Your participation is appreciated. We’ll make sure Krista sees it. I believe she is following the post now.

  5. Rohit Chawla Says:

    I may be a little too late on this subject but will still write nonetheless. Compression and Bursting Strength are generally but not necessarily related to each other. And agree to Jeff’s statement “Due to diferences in liner combinations and various other factors, you may end up with different results.”
    Building up on the same concept, I would like to share an article or writeup I made sometime ago on “Performance of a Carton”.

    http://www.slideshare.net/rohitchawlaindia/performance-of-a-carton-a5-simple

    Bouquets and Brick-Bats shall be appreciated…. LOL…

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