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"Seal Validation and Seal Strength Testing"

I recently inherited a sealer validation project. Having never worked on packaging equipment before, I'm looking for guidance in determining the burst requirement for my packaging. The contract manufacturing company I am working with has conducted burst tests and recorded the values for me. They have informed me that they typically take 70% of the average from the samples that were set at the minimum parameter settings. When I questioned how this was derived, they were unable to provide the source. The question I have for you, is this approach sound and consistent with industry practices? I'm currently awaiting for my copy of F1140-00 and F2054-00. Are there any other sources I should be referencing?

Last Updated On September 4, 2019

Before attempting to use a burst tester to validate a sealer, it is important to first determine if burst testing is suitable for evaluation of seals in the specific package type you are working with. While a burst test might be useful in a standard flat rectangular pouch, there are many types of packages where burst testing will not help determine the suitability of a specific seal.

If the package has certain types of opening features, the failure of that feature prior to the final seal will make burst testing for seal strength impossible. It is also difficult to use a burst tester for seal testing on any package that has multiple components such as a breather bag or a pouch with fitments. The final seal you want to optimize may be stronger than the other components and the package would fail during burst testing before the seal conditions were optimized and validated.

Similarly using a burst tester to validate seals on a tray is very difficult. The differences in strength and extensibility between the tray and the lidding material make it difficult to optimize seals using a burst tester.

A burst test is really a stress test for the entire package, not just one seal. Therefore it can only be used to optimize a seal if that seal is equal to or weaker than the other seals and the other components of the package. When performing a heat seal validation, ASTM F88 (Standard Test Method for Seal Strength of Flexible Barrier Materials) is more frequently employed. This test allows the user to assess each seal area separately against the appropriate requirements. For further information on seal validation it may also be helpful to review the GHTF Process Validation Guidance GHTF/SG3/N99-10: 2004 Edition 2.