Overview
EN ISO 9073-4:2021 - "Nonwovens - Test methods - Part 4: Determination of tear resistance by the trapezoid procedure" - is a standardized test method published by CEN/ISO for measuring the tear resistance of nonwoven materials using the trapezoid test specimen and a tensile-testing machine. The document defines specimen preparation, conditioning, apparatus requirements, test execution and reporting so results are comparable across laboratories and suppliers.
Key Topics and Requirements
- Scope: Applies to all nonwovens for determination of tear resistance by the trapezoid procedure (ISO 9073-4:2021).
- Specimen dimensions & preparation:
- Cut specimens nominally (75 ± 1) mm × (150 ± 2) mm.
- Mark an isosceles trapezoid with a 15 mm preliminary cut in the centre of the short side.
- Test five specimens in the machine direction and five in the cross-machine direction unless otherwise agreed.
- Conditioning & wet testing:
- Condition specimens in the standard atmosphere per ISO 139 (recommended ≥24 h relaxed).
- For wet testing, immerse specimens 1 hour in Grade 3 water (ISO 3696) at 20 ± 2 °C; for poorly wettable materials a nonionic wetting agent (≤1 g/L) is permitted.
- Apparatus & machine settings:
- Use a CRE (constant rate of extension) tensile-testing machine with gauge length (25 ± 1) mm and extension rate (100 ± 10) mm/min.
- Force-measuring accuracy to Class 1 per ISO 7500-1; data acquisition at ≥8 samples/s if used.
- Jaws must hold specimens without slippage or damage; jaw width preferably 100 mm.
- Procedure & results:
- Clamp the non-parallel trapezoid sides with the cut midway between clamps; start the test and record the tearing force.
- Test result is the arithmetic mean of maximum forces from the series of specimens; specimens that do not tear correctly are discarded and replaced.
Applications and Who Uses It
- Manufacturers of nonwovens and technical textiles use this standard to specify product performance (medical wipes, geotextiles, filtration media, hygiene products).
- Quality control laboratories and third-party test houses apply the method for acceptance testing, R&D comparisons and supplier qualification.
- Specifiers and procurement teams reference EN ISO 9073-4:2021 in material standards, tenders and product datasheets to ensure consistent tear-resistance metrics.
- Useful for product development where tear propagation characteristics affect durability, safety and end-use performance.
Related Standards
- ISO 139 - Standard atmospheres for conditioning and testing
- ISO 3696 - Water for analytical laboratory use (Grade 3)
- ISO 7500-1 - Calibration/verification of tensile testing machines
- ISO 186 - Sampling (for specimen selection)
By following EN ISO 9073-4:2021, organizations achieve reproducible tear resistance data for nonwovens using the trapezoid procedure, enabling reliable product comparison and quality assurance.
