Trims & Fasteners

Zipper Lateral Pull Strength Calculator (ASTM D2061)

Zippers rarely fail end to end. They burst sideways, which is the load this test applies and the one the specification should quote.

Specimen Forces Crosswise
N
N
N
Chain & Specification Acceptance
no.
mm
N

Mean Lateral Pull Strength

— N

Average bursting force across the three specimens

Series & Margin

Standard Deviation
— N
Coefficient of Variation
— %
Margin Over Minimum
— N
Minimum Against Result
— %
Elements Under Load
— no.
Load per Element
— N

Load per element assumes the gripped length shares equally, which a real burst does not — failure starts at one element and unzips from there, so the first element sees more than the average. Report the lowest specimen alongside the mean, since that is closer to what a garment will experience.

Zipper Lateral Pull Strength Calculator (ASTM D2061) — free, with the formula and a worked example, at Textile School.