3.3 Rigging & Sling Selection Standards (OSHA 1910.184)

Rigging slings represent the primary structural link connecting an overhead crane's hook to the load. Choosing the proper sling requires thorough understanding of material properties, environmental limitations, mandatory identification standards, and edge protection requirements. Governance for sling usage in overhead industrial lifting is mandated by OSHA 1910.184 (Slings) and ASME B30.9 (Slings).

Primary Sling Classifications & Selection Criteria

Riggers must select slings based on load geometry, weight, sharp edge hazards, operating temperatures, and ambient chemical exposure.

1. Alloy Steel Chain Slings

Alloy steel chain slings are renowned for their extreme durability, flexibility, abrasion resistance, and high-temperature tolerance.

• Approved Overhead Lifting Grades: OSHA 1910.184 strictly mandates that only Grade 80 and Grade 100 alloy steel chains may be used for overhead lifting. Carbon steel chains, Grade 30 (Proof Coil), Grade 40 (High Test), and Grade 70 (Transport/Logistics Chain) are strictly prohibited for overhead crane lifting due to low ductility and rapid catastrophic failure characteristics.
• Properties: Grade 100 chain provides approximately 25% higher working load limit than Grade 80 of equivalent diameter. Chain slings can operate at elevated temperatures up to 1000°F (538°C), provided proper manufacturer thermal de-rating factors are applied above 400°F (204°C).

2. Wire Rope Slings

Wire rope slings provide a balance of strength, flexibility, fatigue resistance, and reserve strength.

• Construction & Grades: Wire rope slings for overhead lifting are fabricated from Extra Improved Plow Steel (EIPS) or Extra Extra Improved Plow Steel (EEIPS). The standard industrial construction is 6x19 or 6x36 classification.
• Core Types: Slings must feature an Independent Wire Rope Core (IWRC) for overhead industrial applications. IWRC provides superior crushing resistance when wrapped around loads and maintains structural integrity under heavy tension. Fiber Core (FC) ropes contain sisal or synthetic fibers, which lack thermal resistance and crush easily under heavy loads.

3. Synthetic Web & Synthetic Roundslings

Synthetic slings are lightweight, highly flexible, non-marring, and non-conductive, making them ideal for polished shafts, painted assemblies, and delicate machinery.

• Material Differences & Chemical Sensitivities:
  • Nylon (Polyamide): Resistant to alkalis, grease, and hydrocarbons, but severely degraded by acids and bleaching agents. Nylon stretches up to 6% to 8% at rated capacity, absorbing shock loads.
  • Polyester (Polyethylene Terephthalate): Resistant to acids and bleaching agents, but severely degraded by alkalis and strong bases. Polyester stretches only ~3% at rated capacity, providing tighter load control.
  • High-Performance Modular Polyethylene (HPPE/Dyneema): Exceptional strength-to-weight ratio, extreme cut resistance, and low stretch, suitable for heavy industrial picks.
• Synthetic Roundslings: Composed of continuous loops of synthetic core yarns encased in a protective woven outer jacket.

4. Metal Mesh Slings

Fabricated from high-tensile steel wire mesh attached to end handles. Metal mesh slings excel in handling hot, abrasive, or sharp metal stock, such as steel bar inventory, coils, and castings, without suffering cutting or tearing damage.

Mandatory Sling Identification Tags

Under OSHA 1910.184 and ASME B30.9, every sling must feature a permanently attached, durable identification tag. Using an untagged, illegible, or modified sling is a serious safety violation. If a sling tag is missing or unreadable, the sling must be removed from service immediately.

The tag must contain the following permanent information:

1. Name or trademark of the manufacturer
2. Material grade (e.g., Grade 80 / Grade 100 chain, EIPS wire rope, Nylon/Polyester)
3. Rated load capacities for vertical, choker, and basket hitch configurations
4. Stock diameter or size and sling length / reach
5. Serial number or tracking ID

Edge Protection Requirements

Sharp load corners present an extreme shearing hazard to rigging slings. When a sling is tensioned against a corner whose radius is smaller than the sling's thickness or wire rope diameter, concentrated cutting stresses drastically reduce sling strength or sever the sling entirely.

• Mandatory Corner Protection: Riggers must install approved edge protection—such as split heavy-wall pipe, engineered polyurethane corner guards, aluminum saddles, or reinforced rubber padding—on all sharp corners.
• Protection Application: Edge protection must be used regardless of sling material. While synthetic slings cut easiest, sharp steel corners can cut wire rope strands and gouge alloy chain links.

Environmental Degradation & Thermal Limits

Riggers must inspect synthetic slings daily for sun-bleaching, stiffening, chemical burns, or melted fibers. Any synthetic sling exposed to temperatures exceeding 194°F or showing chemical degradation must be removed from service and destroyed.