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Inflation Burst

"Calculating Burst Values"

How do you determine the minimum burst value of a pouch? Example would be a pouch measuring 5 x 5 in. ID with a seal strength of 1 lb/in.

Last Updated On April 18, 2011

It is important to understand that the burst value of a pouch of a given seal strength (e.g., 1 lb/in.) is dependent upon a number of factors including:

• The dimensions of the pouch—the size of the pouch as well as the width-to-length ratio directly impact the burst value. In general, the larger the pouch, the lower the value.
• The configuration of the pouch—e.g., the same size chevron, three-side seal, and header bag will yield different burst values.
• The materials of construction—nonporous pouches will yield significantly different results than pouches that include a porous material. In addition, the extensibility of the materials used to construct the pouch can affect the results.
• Test equipment.
• Rate of air flow into the package.
• Sensitivity of burst test equipment (machine response to pressure drop).
• Whether or not restraining plates are used, and if so, their gap separation. Because of the complexity of the stresses that the seal experiences, theoretical models for predicting the correlation between seal strength values as tested via a tensile test (i.e., ASTM F88) and burst value historically have had very poor results. Therefore, empirical studies are the preferred method of determining the relationship between tensile seal strength and burst test values. This can be accomplished through a ladder study where packages with differing tensile seal strength values are created and the corresponding burst strengths value determine. Regression analysis can then be employed to characterize the relationship between the values.