Overview
EN ISO 5079:2020 - Textile fibres: Determination of breaking force and elongation at break of individual fibres specifies a standardized tensile test for measuring the breaking force and elongation at break of single textile fibres in the conditioned or wet state. The method is restricted to tests carried out on a constant-rate-of-extension (CRE) testing machine to reduce inter-equipment variability. It applies to all fibre types (including crimped fibres) provided the available fibre length allows the required gauge length.
Key topics and technical requirements
- Test principle: an individual fibre is extended at a constant rate until rupture; force and elongation are recorded. Breaking tenacity requires a linear-density measurement.
- Equipment:
- CRE tensile testing machine with one fixed clamp and one moving clamp (constant speed).
- Clamps suitable for individual fibres; visualization of force/extension curves recommended to detect slippage.
- Tweezers and wetting solution for wet-state tests.
- Metrology and accuracy:
- Machine verification per ISO 10012 and ISO 7500-1 (accuracy class 1).
- Force error ≤ ±1 %; extension error ≤ ±0.1 mm; gauge length accuracy ±0.2 mm; constant-rate displacement accuracy ±5 %.
- Operable rates of extension typically between 5 mm/min and 40 mm/min.
- Conditioning and sampling: follow standard atmospheres (e.g., ISO 139) and sampling methods (e.g., ISO 1130) as cited.
- Results and reporting: report breaking force (preferably in centinewtons), elongation at break (%), and, if required, breaking tenacity (cN/dtex). Annexes provide guidance on specimen mounting (Annex A) and testing of high‑tenacity filaments (Annex B).
Applications and users
EN ISO 5079:2020 is intended for:
- Textile testing laboratories performing fibre-level tensile characterization.
- Fibre and yarn manufacturers validating raw material performance.
- R&D teams and product engineers developing high-performance or specialty fibres.
- Quality assurance and compliance teams requiring reproducible comparison of fibre strength and elongation.
- Instrument manufacturers seeking conformance criteria for CRE tensile testers.
Practical uses include comparing fibre strength across batches, determining elongation properties for process control, calculating tenacity for performance specifications, and supporting product development where single-fibre behavior is critical.
Related standards
Keywords: EN ISO 5079:2020, textile fibres, breaking force, elongation at break, constant-rate-of-extension, tensile testing machine, breaking tenacity, fibre testing.