Crane Rentals: Wire Rope Inspection And Obvious Signs That The Wires Need To Be Replaced

Although crane rental companies are responsible for providing periodic maintenance services, it is the renter's responsibility to inspect the cranes before every shift to ensure that all components are in working condition. As outlined in Regulation Standard 1926.1413(a)(1) by the Occupational Safety and Health Administration, the renting company must have a competent person inspect the equipment before and after each shift. The condition of the wire ropes is of particular concern, and should be inspected while running and standing. 

An Overview Of Wire Rope Inspections

Wire ropes must be inspected periodically because they are considered as a consumable part of the crane, and will deteriorate with each use. During its life, the physical properties of the wire will change. This affects the structural integrity and performance of the wires, which ultimately affects the safety of all workers on site considering the fact that 90% of all crane accidents occur due to human error and 40% of all victims were struck by an object. Wire rope inspections greatly reduce the risk of an accident happening, as the wire ropes can be replaced and removed before they become a safety hazard.

Wire rope inspections should assess the condition of as much as the rope length as possible with an emphasis at the points of attachment. Most experts recommend paying special attention to the rope zones subject to the highest number of cycles, pick-up points, sheaves, end fittings and wires that are subject to hostile working conditions.

Obvious Signs Of Deterioration

Wire rope inspections measure the rate of deterioration and look for obvious signs of deterioration, so that the wire ropes are removed and replaced before an accident can happen. Some obvious signs of deterioration indicating that the wire ropes need to be replaced include:

  • broken wires. Wire ropes generally break at a steady rate. Wire ropes need to be replaced when there are 6 or more broken wires in one rope lay length for running ropes or 3 more or more broken wires in one strand in one rope lay. 
  • a reduction in the diameter of the wires. A reduction in the diameter of the wires can be caused by natural abrasion or corrosion. Although a minor reduction in the diameter of the wires is not a concern, wires that exhibit wear exceeding 1/3 of the original diameter should be replaced immediately.
  • strong presence of corrosion. Regardless of whether the corrosion is present on the external or internal surface, wire ropes should be replaced when there is evidence of severe roughening or pitting.
  • rope deformation. There are many different ways that the wires can be deformed. The wires should be replaces when you see waves, birdcages ( which is when the outer strands of wires are longer than the inner strands), loop formations, loose wires, nodes, misplaced outer wires, kinks and flat areas. These deformations generally indicate that the structural integrity of the wire ropes are heavily compromised, and that the wires may break at any given time. 
  • presence of damaged caused by excessive heat. Check for burn marks on the wires.

Depending on the condition of the wires, they may need to be cleaned prior to being inspected, so that no flaws can be concealed. Use a wire brush and a scraper to remove any particles that cling onto the surface of the wire ropes.

Conclusion

Depending on the terms and conditions of your rental agreement, you may be responsible for the full cost of replacing wire ropes. Some rental companies will partially reimburse you for the cost. It is important to fully understand what you are responsible for, and what you can expect from the rental companies before signing the rental contract. 

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