Overview
ISO 1139:2025 - Textiles - Designation of yarns defines standardized, concise notations for describing yarn construction using the Tex system. The second edition (2025) specifies two complementary notation methods for single, folded, cabled and multiple wound yarns: the single-to-fold method (starting from single-yarn linear density) and the fold-to-single method (starting from the resultant linear density). The notation covers linear density (tex), number of filaments, direction and amount of twist, and number of folds. It excludes certain special yarns (for example, fancy, textured/bulked, wrapped-core yarns) and does not specify constituent fibres, after-treatment or package type.
Key topics and technical requirements
- Linear density in the Tex system: All linear densities are expressed in tex (and submultiples where applicable) as nominal or actual values.
- Yarn construction elements: Notation must capture number of filaments, twist direction (Z or S), twist amount (turns per metre or explicit unit), and number of folds/cables.
- Two notation methods:
- Single-to-fold notation: Starts from single yarn parameters; uses the multiplication sign (×) to indicate folding/plying.
- Fold-to-single notation: Starts from resultant linear density of the final yarn; uses the solidus (/) in the notation.
- Nominal vs actual values: Nominal values are used for general description and commercial transactions (subject to tolerances); actual values come from authorized test procedures.
- Resultant linear density: The standard recognizes that folding, cabling and twist can change resultant linear density and that manufacturing conditions (tension, machine type, moisture) influence final values.
- Symbols and terminology: Uses standardized terms (single yarn, folded yarn, cabled yarn, multiple wound yarn) and symbols consistent with ISO conventions.
Applications
- Standardized yarn specification and labeling for procurement and trade.
- Technical communication between spinners, textile mills, converters, and testers.
- Basis for manufacturing calculations (machine settings, material planning) using nominal tex values.
- Input to quality control, testing reports and product datasheets when reporting actual measured values.
- Useful for industries producing woven/knitted fabrics, ropes, fishing nets and technical textiles where precise yarn description is required.
Who should use ISO 1139:2025
- Yarn and textile manufacturers
- Quality assurance and laboratory testing teams
- Product designers and textile engineers
- Procurement and specification writers in textile supply chains
- Standards committees and educators in textile technology
Related standards
- ISO 1144 (linear density nomenclature / tex/dtex)
- ISO 2061 (twist measurement terminology)
- ISO 858 (yarns for fishing nets-uses single-to-fold notation)
- ISO 2947 (lists of nominal linear densities and industry practice)
ISO 1139:2025 provides a clear, consistent framework for yarn designation, improving interoperability across textile production, testing and trade while aligning with established ISO terminology and measurement practices.
