GIFSQ Tools · Module 10 — Packaging & Shelf-Life · Tool 187 of 500
Turn a peel-test peak force and seal width into seal strength in N/15 mm and N/m, and check it against your specification minimum (ASTM F88).
Try sample values — fills the form with the worked example below.
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Seal strength (N/15 mm)
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Seal strength (N/m)
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Margin over spec (%)
Equation: Seal strength (N/15 mm) = peak force (N) ÷ seal width (mm) × 15. Seal strength (N/m) = peak force (N) ÷ seal width (m). Margin (%) = (strength − minimum) ÷ minimum × 100.
Method: Seal strength by ASTM F88 (standard test method for seal strength of flexible barrier materials): peel the seal at a controlled rate and record the peak force, then normalise by the seal width.
Assumptions: the seal is peeled at the rate and angle in ASTM F88; the width is the sealed width, measured across the seal.
Limitations: a single peel says nothing about seal integrity under flexing, heat or storage; strength and leak-tightness are different properties and both must be checked.
Rounding: strength to 2 decimal places; margin to 2 decimal places; intermediates unrounded.
This is a calculation aid, not a laboratory report — confirm against your accredited method before citing a value.
Method: Seal strength by ASTM F88 (standard test method for seal strength of flexible barrier materials): peel the seal at a controlled rate and record the peak force, then normalise by the seal width.
Assumptions: the seal is peeled at the rate and angle in ASTM F88; the width is the sealed width, measured across the seal.
Limitations: a single peel says nothing about seal integrity under flexing, heat or storage; strength and leak-tightness are different properties and both must be checked.
Rounding: strength to 2 decimal places; margin to 2 decimal places; intermediates unrounded.
This is a calculation aid, not a laboratory report — confirm against your accredited method before citing a value.
Worked example: A 45 N peak force on a 15 mm seal: strength = 45 ÷ 15 × 15 = 45.00 N/15 mm (3,000.00 N/m); against a 30 N/15 mm minimum the margin is 50.00%.
Enter values above to see results.
Typical minimum: 20–30 N/15 mm for flexible pouches — always use the value in your own product specification. Tool 187 of 500 — GIFSQ
