ISO 3377-2:2016

Overview

ISO 3377-2:2016 defines the standardized method for determining the tear load of leather using the double edge tear test, also known as the Baumann tear. Developed by the International Organization for Standardization (ISO), this standard is essential for accurately measuring the tear strength of all types of leather. It ensures consistent, reliable mechanical testing results by specifying precise sample preparation, test apparatus, and procedures.

This part of ISO 3377 supplements Part 1, which covers the single edge tear test, by focusing specifically on tear resistance measured through tearing from two edges. The method is widely recognized in the leather industry to assess durability, quality control, and product performance.

Key Topics

• Scope: Applicable to all leather types for evaluating resistance to tear load from two edges.
• Reference Standards: Includes ISO 2418 for sampling, ISO 2419 for sample preparation and conditioning, ISO 2589 for thickness measurement, and ISO 7500-1 for verifying testing machines.
• Test Principle: A rectangular leather specimen with a specific hole design is subjected to tensile force in a universal testing machine until it tears. The maximal tearing force is recorded.
• Apparatus Requirements:
  • Testing machine with force range suitable to sample strength and recording accuracy of at least ±2%.
  • Specialized specimen holders made from rigid steel strips to secure samples during tearing.
  • Tools conforming to dimensional specifications to cut test specimens accurately.
• Specimen Preparation:
  • Sampling according to ISO 2418.
  • Preparation of six test specimens: three with the longer edge aligned parallel to the backbone (spine), and three perpendicular.
  • Conditioning of specimens under standard atmospheres as per ISO 2419.
  • Thickness measurement following ISO 2589.
• Test Procedure:
  • Specimens are mounted on holders and loaded in the tensile tester at a controlled speed of 100 mm/min ± 20 mm/min.
  • Testing is conducted until complete tearing occurs, capturing maximum tear force.
• Reporting Requirements: Test reports must include tear force averages for both grain directions, specimen thickness, conditioning atmosphere, and any deviations from the standard method.

Applications

ISO 3377-2:2016 is critically important for:

• Leather manufacturers ensuring consistent quality and durability of their products.
• Footwear, upholstery, leather goods, and automotive industries where leather tear resistance impacts product lifespan and safety.
• Product development and R&D teams that require standardized testing to compare materials or optimize processing methods.
• Quality assurance laboratories performing routine mechanical tests to certify leather for compliance with customer or regulatory requirements.

By implementing this standard, organizations achieve:

• Reliable benchmarking of mechanical properties across different leather batches.
• Improved consumer confidence due to certified material strength.
• Streamlined acceptance criteria between suppliers and clients.
• Enhanced understanding of leather performance under mechanical stress conditions.

Related Standards

• ISO 3377-1: Leather - Physical and mechanical tests - Determination of tear load - Part 1: Single edge tear
• ISO 2418: Leather - Chemical, physical and mechanical tests - Sampling location
• ISO 2419: Leather - Physical and mechanical tests - Preparation and conditioning of test specimens
• ISO 2589: Leather - Physical and mechanical tests - Determination of thickness
• ISO 7500-1: Metallic materials - Verification of static uniaxial testing machines - Part 1: Tensile/compression testing machines - Verification and calibration of force measurement system

Adhering to these complementary standards ensures a comprehensive and harmonized approach to leather testing and evaluation.

By following ISO 3377-2:2016, professionals in the leather industry can confidently assess tear resistance with a respected, internationally recognized testing protocol that supports product quality, research insights, and regulatory compliance.