Safety Focus of the Week: Basic Rigging – Wire Rope Slings
Wire Rope Slings are another common rigging item that we use on the jobsites, in the yard, and in our shops. The major advantage wire rope is that it would be suitable for handling hot materials (up to 180 deg F for fiber core and 400 deg F for metallic core). The wire rope sling is also light-weight, durable, abrasion resistant, and forms to the shape of the lifted object.
Aside from the capacity and length, an important consideration in selecting the sling is the end connections. The options include mechanical fitting, braided, or clipped open loops, a variety of thimble types, hooks, and a variety of specialty sockets, eyes, and threaded ends. The main thing to consider for an eye loop is that the hook or shackle should be at least the nominal diameter of the cable.
When lifting, the D/d ratio (D=dia of lifted object; d=dia of cable) should be 25:1 or greater. Also protect the cable from sharp corners that will kink or damage the cable.
OSHA provides a comprehensive Guideline for wire rope slings: https://www.osha.gov/dsg/guidance/slings/wire.html
and the accompanying Figures and Tables: https://www.osha.gov/dsg/guidance/slings/tables-figures.html
Finally, as with all rigging, daily inspections are required before putting the rigging into service. For wire rope slings, look for the following:
- Broken Wires
- Kinking/Crushing/Bird Caging
- Evidence of Heat Damage
- Crushed/Deformed/Worn/Corroded End Attachments or Fittings
- Missing or Illegible Sling Identifications
Remove the rigging from service upon identifying one of these defects and provide to the safety department for further evaluation.