EN ISO 2061:2015 PDF

Overview

EN ISO 2061:2015 - Textiles: Determination of twist in yarns - Direct counting method specifies a laboratory procedure to measure the direction of twist, the amount of twist (expressed as turns per unit length, e.g., turns/m), and the change in length on untwisting using a direct counting technique. Published by ISO and adopted by CEN as EN ISO 2061:2015, the standard addresses single yarns (spun and filament), plied yarns and cabled yarns with separate procedures for each type. It is primarily intended for yarns in packages, and - with precautions - for yarns removed from fabrics.

Key topics and technical requirements

• Measured parameters: direction of twist (S/Z), twist level (turns per unit length), and untwist-induced change in length.
• Yarn types covered: single spun, single filament, plied and cabled yarns (procedures tailored to each).
• Plied/cabled detail:
  • Plied yarns: final plied twist and original twist of singles before plying.
  • Cabled yarns: final cabling twist, the original twist of plied yarn after plying (prior to final processing), and the single-yarn twist before plying.
• Procedure content: sampling, specimen lengths, conditioning (standard atmosphere), apparatus and clamping, Procedure 1 (direction), Procedure 2 (amount of twist), calculations, twist factor and test reporting.
• Limitations: not suitable for monofilaments, many open‑end or intermingled multifilament yarn products, or yarns too large to clamp without distortion. By agreement only for yarns that stretch >0.5% when tension increases from 0.5 cN to 1.0 cN per unit linear density (tex).
• Outputs: average twist per specimen/sample, variation of observations, percentage change in length on untwisting, and twist factor (α).

Applications and users

EN ISO 2061:2015 is used by:

• Textile and yarn manufacturers for quality control and process optimisation.
• Independent testing laboratories and certification bodies for compliance testing.
• R&D teams and textile engineers characterising yarn structure and performance.
• Converters, knitters/woven-fabric producers and procurement teams specifying yarn acceptance criteria.

Practical uses include acceptance testing of incoming yarns, troubleshooting twisting/plying and cabling operations, correlating yarn twist to fabric appearance and mechanical performance, and documenting twist parameters in supplier specifications.

Related standards

• ISO 2 - Designation of the direction of twist in yarns and related products.
• ISO 139 - Standard atmospheres for conditioning and testing.
• ISO 1890 and ISO 7211‑4 - referenced for specialized applications (glass textiles and related test methods).

Keywords: EN ISO 2061:2015, twist in yarns, direct counting method, yarn twist, turns per metre, twist factor, plied yarns, cabled yarns, textile testing standard.