ISO 858:1973

Overview

ISO 858:1973 specifies how to designate fishing net netting yarns using the Tex System (linear density in tex). The standard establishes a consistent, machine- and procurement-friendly notation for single yarns, folded yarns, cabled yarns and braided yarns used in fishing nets. It replaces the earlier ISO Recommendation R 858‑1968 and is intended mainly for grey (unprepared) netting yarns.

Key topics and requirements

• Designation format (complete) - Five characteristics in order:
  1. Linear density of the single yarn (in tex)
  2. Number of single yarns in the first fold
  3. Number of folded yarns (or folded then cabled yarns) in the finished product
  4. Resultant linear density (in tex), preceded by the letter R
  5. Final twist direction, indicated by S or Z (per ISO 2)
• Notation rules
  • The first three numeric characteristics are joined by the multiplication sign (X).
  • The resultant linear density (R...) and the twist letter are separated from the first three characteristics by a semicolon (;).
  • Example: 23 tex X 6 X 3; R 460 tex Z
• Particular cases / brief designation
  • Yarns composed of dissimilar components or heavily twisted trawl twines may be designated by only the resultant linear density and the final twist direction to avoid overly complex notation.
  • Example (brief): R 4000 tex S
• Braided yarns
  • Braided netting yarns are designated only by their resultant linear density (R...).
• Important technical note
  • The resultant linear density differs from the simple sum (total) of component linear densities; twisting and cabling increase the measured resultant linear density versus the calculated total from components.
  • The term nominal denotes a reference value useful for designation, not an exact measured value.

Applications and users

ISO 858:1973 is practical for:

• Fishing-net manufacturers and yarn suppliers for clear product specification and labeling
• Gear designers and marine engineers specifying net materials by linear density and twist
• Procurement and quality-control teams verifying delivered netting yarns
• Textile laboratories and standards bodies applying consistent Tex‑based designations

Keywords: fishing nets, netting yarns, Tex System, linear density, yarn designation, twist direction, braided yarns, cabled yarns.

Related standards

• ISO 2 - Designation of the direction of twist in yarns and related products
• ISO 1139 - Textiles - Designation of yarns
• ISO 1144 - Textiles - Universal system for designating linear density (Tex System)