ISO 4602:2010

Overview

ISO 4602:2010 defines standardized procedures for determining the number of yarns per unit length in woven textile-reinforcement fabrics made of glass, carbon, aramid or other reinforcement fibres. The standard supports consistent yarn count measurement for material specification and composite quality control by specifying two complementary methods (Method A and Method B), required apparatus and reporting elements.

Key Topics

• Scope: Measurement of yarns in the warp and the weft of woven reinforcement fabrics used in composite materials.
• Two methods:
  • Method A - count a fixed number of yarns (preferably 50 or more; minimum 20 when spacing exceeds limits) and measure the distance between the first and last counted yarn.
  • Method B - count all yarns (including partial yarns, to the nearest tenth) within a fixed distance (10 mm to 200 mm), ensuring at least 20 yarns are included where possible.
• Apparatus: simple and practical tools are specified, for example:
  • a graduated rule (millimetres),
  • a yarn-counting device (counting glass with lens magnifications typically ×7 to ×10, or a traversing microscope),
  • a suitable needle for separating yarns when needed.
• Test area and positioning: samples must be laid flat and untensioned; measurements should not be made within 50 mm of fabric edges or selvedges.
• Replicates: at least four measurements in different positions are recommended (reduced to three or two only by agreement for narrow fabrics).
• Expression of results: convert counts to a chosen unit length (10 mm or 25 mm) and report average warp and weft yarns per unit length to three significant figures.
• Precision: interlaboratory precision is not available; the standard states that a precision statement will be added when such data exist.

Applications

ISO 4602:2010 is practical for laboratories, manufacturers and quality engineers working with composite reinforcement textiles. Common applications include:

• Verification of fabric architecture for composite layup and design.
• Material specification and acceptance testing for glass, carbon and aramid reinforcement fabrics.
• Process control in textile and composite manufacturing where consistent yarn density affects mechanical performance.
• Supporting procurement and certificate-of-conformance documentation through standardized test reporting.

Related Standards

• ISO 4602:2010 should be used alongside material and composite standards that reference yarn count or fabric architecture.
• Test reports should reference ISO 4602:2010 and specify which method (A or B) was used, plus details such as window size of the counting glass, individual measurements and averages, and any deviations from the procedure.

By following ISO 4602:2010, organizations ensure repeatable, documented yarn-count measurements that feed directly into material specifications and composite quality assurance processes.