ISO 3377-1:2011

Overview

ISO 3377-1:2011 specifies a standardized method to determine the tear strength of leather using a single-edge tear (commonly called a "trouser tear"). This test is applicable to all types of leather and is intended for routine quality control, material specification and comparative testing between batches or treatments.

The method records the mean force required to propagate a tear from the end of a slit in a rectangular test specimen. The standard emphasizes reproducible sampling, sample conditioning and clear evaluation rules so results can be compared within and between laboratories.

Key Topics

• Specimen and sampling: Obtain test pieces in accordance with ISO 2418 and prepare/condition them per ISO 2419. Typically six specimens are cut - three with the long side parallel to the backbone and three perpendicular - unless alternate sampling rules apply.
• Apparatus requirements:
  • Tensile testing machine with a force range appropriate to leather and force-measuring accuracy at least 2 % (Class 2 of ISO 7500-1).
  • Uniform jaw separation speed of 100 mm/min ± 20 mm/min and jaw width minimum 50 mm ± 2 mm.
  • Thickness gauge as specified in ISO 2589 and a press knife able to cut the specified specimen in one operation.
• Test procedure:
  • Clamp one leg of the specimen in each jaw (other leg folded 180°) so long edges are parallel to the test direction and run until complete separation.
  • Record force-extension trace throughout the tear.
• Evaluation:
  • The tear load is determined as the arithmetic mean of the forces on the central portion of the peak trace (the two middle quarters). Electronic evaluation using all data points in the middle subsections is preferred and required in case of litigation.
  • A manual method is allowed but must be noted in the report; it uses selected peaks and valleys and can yield different results from electronic evaluation.

Applications

• Routine quality control of leather for footwear, leather goods and upholstery.
• Comparative testing of processing treatments, tanning methods or coatings that affect tear resistance.
• Material specification and acceptance testing where tear strength is a performance criterion.

Practical value: the standard provides a repeatable protocol and clear reporting requirements that help manufacturers, test labs and purchasers compare tear strength data reliably.

Related Standards

• ISO 3377-2 (Double edge tear)
• ISO 2418 (Sampling location)
• ISO 2419 (Sample preparation and conditioning)
• ISO 2589 (Thickness measurement)
• ISO 7500-1 (Verification of tensile testing machine force-measuring system)

For test reporting, include reference to ISO 3377-1:2011, sample identification, thickness, specimen orientation results, conditioning atmosphere and any deviations from the method. This ensures traceable, comparable tear-load data for decision-making.