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:
- Linear density of the single yarn (in tex)
- Number of single yarns in the first fold
- Number of folded yarns (or folded then cabled yarns) in the finished product
- Resultant linear density (in tex), preceded by the letter R
- 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)
