Overview
EN ISO 3379:2024 - “Leather - Determination of distension and strength of surface (Ball burst method)” (ISO 3379:2024) is a CEN-adopted international test standard for assessing the distension (stretchability) and surface strength of leather. It specifies a reproducible ball-burst test in which a hemispherical steel ball distends a clamped circular leather specimen from the reverse side. The method is applicable to all flexible leathers and is particularly suited to determine lastability for footwear uppers and other applications where the wearing surface must resist cracking.
Key topics and technical requirements
- Test principle: A circular test piece is clamped around its edge and distended by a hemispherical plunger; the distension at first surface crack (first damage) and, if applicable, the distension at burst are recorded.
- Specimen preparation and conditioning: Follow ISO 2418 (specimen position/preparation) and ISO 2419 (conditioning). At least three circular test pieces are recommended.
- Apparatus parameters:
- Clamp aperture diameter: 25.0 mm ± 0.5 mm
- Plunger (hemispherical end) nominal diameter: 6.25 mm ± 0.05 mm
- Plunger travel rate: 0.20 mm/s ± 0.05 mm/s
- Displacement measurement accuracy: ±0.05 mm
- Force measurement accuracy: ±10 N
- Measurements reported: Distension (mm) to nearest 0.1 mm and force (N) to nearest 10 N at cracking and at burst. Special notes address patent leather behaviour and force–displacement curve interpretation.
- Related instrumentation: Press knife for cutting circular specimens (ISO 2418), thickness gauge (ISO 2589), and clamp design that prevents specimen slippage.
Applications and users
- Primary users: Leather manufacturers, footwear component producers, quality-control and testing laboratories, and material engineers assessing leather performance.
- Practical uses:
- Evaluate lastability and suitability of leather for footwear uppers.
- Compare surface durability between leather grades, finishes, or treatments.
- Quality control acceptance testing and supplier verification.
- Support product development where surface cracking resistance is critical (footwear, apparel, upholstery).
- Using EN ISO 3379:2024 helps manufacturers reduce product failures linked to surface cracking and supports consistent, comparable test data for procurement and compliance.
Related standards
- ISO 2418 - specimen position and preparation for leather tests
- ISO 2419 - conditioning of leather specimens
- ISO 2589 - leather thickness measurement
- ISO 15115 / EN 15987 - leather vocabulary and terminology
Keywords: EN ISO 3379:2024, ball burst method, leather testing, distension, surface strength, lastability, footwear uppers, grain cracking, test method.