ISO 20932-1:2018

Overview

ISO 20932-1:2018 - Textiles: Determination of the elasticity of fabrics - Part 1: Strip tests - specifies laboratory methods for measuring fabric elasticity using straight strip tests or loop tests. The standard covers test specimen preparation, apparatus, testing procedures and result calculations for woven, knitted and non‑woven fabrics (excluding narrow fabrics). It is based on EN 14704-1 and references conditioning and equipment standards to ensure reliable, repeatable elasticity measurements.

Key topics and technical requirements

• Scope and terms: Defines key concepts such as elasticity, elongation, pretension, permanent deformation, force decay and cycle.
• Test methods: Two main specimen methods:
  • Method A - Strip test specimens (full‑width gripped in line clamps).
  • Method B - Loop test specimens (seamed loop placed on a loop bar assembly).
• Apparatus:
  • CRE testing machine (constant‑rate‑of‑extension) with metrological confirmation per ISO 10012 and force/elongation accuracy at least class 1 of ISO 7500‑1.
  • Data acquisition frequency: ≥ 8 samples/s.
  • Extension rates 20–500 mm/min (±10 %); gauge lengths 100–250 mm (±1 mm).
  • Line clamps designed to prevent slippage (convex jaw radius 3 mm) and wide enough for specimen width; pneumatic grips recommended.
  • Loop bar assembly with bar diameters typically 4–8 mm and minimum internal dimension 80 mm.
• Specimen preparation: Procedures for woven, knitted and nonwoven fabrics, including cutting, fraying control and sewing (type 301 lockstitch per ISO 4915) for loop specimens.
• Testing and reporting: Cycling a specimen between gauge length and fixed load/extension; measurement of maximum force, elongation, force decay (time and exercising), permanent deformation and elastic recovery. Sampling guidance is provided (see Annex B).

Applications and practical value

ISO 20932-1:2018 is used to:

• Evaluate elastic performance of fabrics in quality control and product development.
• Compare materials for sportswear, medical textiles, upholstery, technical textiles and other applications where stretch and recovery are critical.
• Provide data for specification writing, supplier agreements and conformity testing.
• Support R&D teams in assessing the behaviour of elastane‑containing or engineered yarn/fabric constructions.

Who should use this standard

• Textile testing laboratories and quality control teams
• Textile engineers and product developers
• Manufacturers of garments, technical and medical textiles
• Standards bodies and compliance officers

Related standards

• ISO 139 - Standard atmospheres for conditioning and testing
• ISO 4915 - Stitch types (sewing for loop specimens)
• ISO 7500‑1 - Verification of tensile testing machines
• ISO 10012 - Measurement management systems
• EN 14704‑1 - Basis for this ISO document

Keywords: ISO 20932-1:2018, textile elasticity test, strip tests, loop tests, CRE testing machine, fabric elongation, elastic recovery, force decay.