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7-3 | Synthetic Rope Sling Construction and Component Specifications

ASME B30.9 has laid out specifications for the construction and components of synthetic rope slings.

Synthetic Ropes

Although ASME B30.9 covers synthetic ropes made from either nylon or polyester fiber materials, fiber rope slings can also be made from a variety of other synthetic fiber materials. These ropes shall be made of fibers that have been produced with an appropriate ultraviolet inhibitor.

Rope constructions covered under ASME B30.9 include three-strand laid, eights-trand plaited, single braided, and double braided. ASME requires that each rope construction be manufactured and tested in accordance with the following Cordage Institute specifications:

Synthetic Rope Slings Construction Component Specifications for Ropes


Fittings should be selected to meet the following requirements:

  • Suitability of mechanical or socketed fittings shall be verified by a Qualified Person
  • Material shall be compatible with the mechanical and environmental requirements imposed on the sling
  • Fittings shall have sufficient strength to sustain twice the rated load of the sling without visible permanent deformation
  • Fitting surfaces in contact with the sling shall be finished to remove edges that could damage the sling
  • Thimbles shall have a minimum diameter at the beating surface of at least 2 times the rope diameter
  • When employed, hooks shall meet the requirements of ASME B30.10
  • When employed, rigging hardware shall meet the requirements of ASME B30.26
Synthetic Rope Slings Construction Component Specifications for Fittings

Other Components

Slings that employ synthetic ropes and fittings other than those listed in ASME B30.9 may be used. When such components are employed, the sling manufacturer or a Qualified Person shall provide specific data regarding deviations from the applicable sections of the B30.9 standard and shall comply with all other requirements of the B30.9 standard.

Lesson tags: Lifting Sling Inspection Course