OSHA advises employers on working with wire rope
Posted January 31, 2017
A new OSHA Safety and Health Information Bulletin (SHIB) advises employers on working safely with wire rope. Recent OSHA investigations found several workplace incidents, many involving fatalities, were connected to wire rope failures.
To assist employers in protecting workers from the hazards of rope wire failure, the new SHIB provides information on how wire rope is structured, what causes degradation, what to look for when inspecting ropes, and how often to inspect them.
According to OSHA, wire ropes used for hoisting, lowering, and horizontally moving suspended loads are subject to high tensile stress and degradation through wear and corrosion. Wire ropes are made up of multiple strands of concentrically wound wire; the degradation of even one strand may result in an unexpected break of that strand and a sudden release in rope tension. This loss of tension may cause the load the rope is holding or the machine it is controlling to fall or move, putting workers at risk for crushing and struck-by injuries.
OSHA says that all wire rope components degrade over time in service but the degradation rate depends on several variables. The degradation rate can depend on such variables as:
- How often the load limit is exceeded;
- Cyclic loading history;
- Proper periodic maintenance and lubrication;
- Abrasive service history;
- Core/rope design and weather; and
- Chemical exposure.
The SHIB also includes a case study of a fatality that took place after a crane’s boom hoist wire rope failed, dropping the boom and load onto workers. The accident occurred in 2013 in Utah. OSHA's Directorate of Technical Support and Emergency Management's Salt Lake Technical Center analyzed rope samples from the section that failed and determined that most of the wires in the rope were already broken from fatigue before the incident occurred.
OSHA concluded that six years of loading and bending likely made the individual wires in the rope more brittle (i.e., metallurgical work hardening) before fatigue and tensile failure occurred. Numerous brittle wires in the rope broke over time and the remaining wires were unable to carry the load failure. Inspectors said that roper rope inspection and maintenance could have prevented the loss of these workers' lives.
General industry and construction standards that apply to wire rope inspection include the following in 29 CFR:
- 1926.251, Rigging equipment for material handling
- 1926.1413, Wire rope – inspection
- 1926.1414, Wire rope – selection and installation criteria
- 1910.179(m), Overhead and gantry cranes – Rope inspection
- 1910.180(d)(6), Crawler locomotive and truck cranes – Inspection records
- 1910.184, Slings – Wire rope
- 1919.79, Wire rope
J. J. Keller's Crane Safety Handbook: For Operators and Ground Crew serves as a jobsite reference for the ground crew, crane operator, competent and qualified persons, and others working with cranes.
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