Wire Rope Slings – Care and Maintenance

Wire_Rope_Sling

Terry Young, president of Construction Safety Experts, in the US, discusses identification, inspection and removal criteria for wire rope slings. The ASMEB30.9-2006 Standard requires wire rope slings to show the name or trademark of the manufacturer, diameter or size, number of legs, if more than one, and the rated loads for the types of hitches used and the angle upon which it is based.

The initial identification is done by the manufacturer and should be maintained by the user so as to be legible during the life of the sling. Replacement of wire rope slings identification should be considered as a repair and is required to be performed by the manufacturer or a qualified person. It must be marked to identify the repairing agency.

Wire rope sling 2

Additional proof testing is not required when replacing sling identification. An initial inspection should be performed prior to using new, altered, modified or repaired wire rope slings. It should be conducted by a designated person to verify compliance with applicable ASME 30.9-2006 standards.

A frequent visual inspection for damage must be performed by the user or designated person each day or shift the sling is used. The best safety practice is to inspect the wire rope before each use, task or lift.

Any condition meeting the ASME 30.9 – 2006 removal criteria or other condition that may result in a hazard must result in the sling being removed from service. The sling should then not be returned to service until approved by a qualified person. Written records are not required for frequent inspections.

A periodic inspection is to be conducted at intervals, not exceeding one year. This requires a complete inspection for damage to the sling by a designated person. The inspection should be conducted on the entire length, including splices, end attachments and fittings.

The frequency of periodic inspections should be based on frequency of use, severity of service conditions, nature of lifts being made and experience gained from the service life of slings used in similar circumstances or conditions.

Guidelines for the time intervals are

  • Normal service – yearly
  • Severe service – monthly to quarterly
  • Special service – as recommended by a qualified person or manufacturer
  • A written record shall be made and maintained of the most recent periodic inspection

Removal criteria

A wire rope sling shall be removed from service if conditions such as the following are present.

  • Missing or illegible sling identification
  • Broken wires
  • For strand- laid and single-part slings, 10 randomly broken wires in one rope lay, or five broken wires in one strand in one lay.
  • For cable-laid slings, 20 broken wires per lay.
  • For six- part braided slings 20 broken wires per braid.
  • For eight-part braided slings 40 broken wires per braid.
  • Severe localized abrasion or scraping
  • Kinking, crushing, birdcaging or any other damage resulting in damage to the rope structure
  • Evidence of heat damage
  • End attachments that are cracked, deformed or worn to the extent that the strength of the sling is substantially affected
  • Severe corrosion of the rope, end attachments or fittings.
  • Other conditions including visible damage that may cause doubt to the continued use of the sling

Hook removal criteria is listed in the ASME B30.10 Standard. Rigging hardware removal criteria is listed in the ASME B30.26 Standard.

Read original article here at International Cranes and Specialized Transport

For all your rigging repairs, inspections and services, call Hercules! Our inspectors are trained to the highest standard and are LEEA registered.

Hercules SLR is part of the Hercules Group of Companies which offers a unique portfolio of businesses nationally with locations from coast to coast. Our companies provide an extensive coverage of products and services that support the success of a wide range of business sectors across Canada including the energy, oil & gas, manufacturing, construction, aerospace, infrastructure, utilities, oil and gas, mining and marine industries.

Hercules Group of Companies is comprised of: Hercules SLRHercules Machining & Millwright ServicesSpartan Industrial MarineStellar Industrial Sales and Wire Rope Atlantic.

We have the ability to provide any solution your business or project will need. Call us today for more information. 1-877-461-4876. Don’t forget to follow us on Twitter LinkedIn and Facebook for more news and upcoming events.

Steel Wire Rope – How, Where, What and Why

steel wire rope

Steel wire rope is several strands of metal wire twisted into a helix forming a composite “rope”, in a pattern known as “laid rope”. Larger diameter wire rope consists of multiple strands of such laid rope in a pattern known as “cable laid”.

In stricter senses the term “steel wire rope” refers to diameter larger than 3/8 inch (9.52 mm), with smaller gauges designated cable or cords. Initially wrought iron wires were used, but today steel is the main material used for wire ropes.

Historically, steel wire rope evolved from wrought iron chains, which had a record of mechanical failure. While Fraying_steel_wire_ropeflaws in chain links or solid steel bars can lead to catastrophic failure, flaws in the wires making up a steel cable are less critical as the other wires easily take up the load. While friction between the individual wires and strands causes wear over the life of the rope, it also helps to compensate for minor failures in the short run.

Steel wire ropes were developed starting with mining hoist applications in the 1830s. Wire ropes are used dynamically for lifting and hoisting in cranes and elevators, and for transmission of mechanical power. Wire rope is also used to transmit force in mechanisms, such as a Bowden cable or the control surfaces of an airplane connected to levers and pedals in the cockpit. Only aircraft cables have WSC (wire strand core). Also, aircraft cables are available in smaller diameters than steel wire rope. For example, aircraft cables are available in 3/64 in. diameter while most wire ropes begin at a 1/4 in. diameter. Static wire ropes are used to support structures such as suspension bridges or as guy wires to support towers. An aerial tramway relies on wire rope to support and move cargo overhead.

History

Modern steel wire rope was invented by the German mining engineer Wilhelm Albert in the years between 1831 and 1834 for use in mining in the Harz Mountains in Clausthal, Lower Saxony, Germany. It was quickly accepted because it proved superior to ropes made of hemp or to metal chains, such as had been used before.

Wilhelm Albert’s first ropes consisted of three strands consisting of four wires each. In 1840, Scotsman Robert Stirling Newall improved the process further. In America wire rope was manufactured by John A. Roebling, starting in 1841 and forming the basis for his success in suspension bridge building. Roebling introduced a number of innovations in the design, materials and manufacture of wire rope. Ever with an ear to technology developments in mining and railroading, Josiah White and Erskine Hazard, principal owners[9] of the Lehigh Coal & Navigation Company (LC&N Co.) — as they had with the first blast furnaces in the Lehigh Valley — built a Wire Rope factory in Mauch Chunk, Pennsylvania in 1848, which provided lift cables for the Ashley Planes project, then the back track planes of the Summit Hill & Mauch Chunk Railroad, improving its attractiveness as a premier tourism destination, and vastly improving the throughput of the coal capacity since return of cars dropped from nearly four hours to less than 20 minutes. The decades were witness to a burgeoning increase in deep shaft mining in both Europe and North America as surface mineral deposits were exhausted and miners had to chase layers along inclined layers. The era was early in railroad development and steam engines lacked sufficient tractive effort to climb steep slopes, so incline plane railways were common. This pushed development of cable hoists rapidly in the United States as surface deposits in the Anthracite Coal Region north and south dove deeper every year, and even the rich deposits in the Panther Creek Valley required LC&N Co. to drive their first shafts into lower slopes beginning Lansford and its Schuylkill County twin-town Coaldale.

The German engineering firm of Adolf Bleichert & Co. was founded in 1874 and began to build bicable aerial tramways for mining in the Ruhr Valley. With important patents, and dozens of working systems in Europe, Bleichert dominated the global industry, later licensing its designs and manufacturing techniques to Trenton Iron Works, New Jersey, USA which built systems across America. Adolf Bleichert & Co. went on to build hundreds of aerial tramways around the world: from Alaska to Argentina, Australia and Spitsbergen. The Bleichert company also built hundreds of aerial tramways for both the Imperial German Army and the Wehrmacht.

In the last half of the 19th century, steel wire rope systems were used as a means of transmitting mechanical power including for the new cable cars. Wire rope systems cost one-tenth as much and had lower friction losses than line shafts. Because of these advantages, wire rope systems were used to transmit power for a distance of a few miles or kilometers.

Safety

The steel wire ropes are stressed by fluctuating forces, by wear, by corrosion and in seldom cases by extreme forces. The rope life is finite and the safety is only ensured by inspection for the detection of wire breaks on a reference rope length, of cross-section loss, as well as other failures so that the wire rope can be replaced before a dangerous situation occurs. Installations should be designed to facilitate the inspection of the wire ropes.

Read more about Wire Rope here

Hercules SLR is part of the Hercules Group of Companies which offers a unique portfolio of businesses nationally with locations from coast to coast. Our companies provide an extensive coverage of products and services that support the success of a wide range of business sectors across Canada including the energy, oil & gas, manufacturing, construction, aerospace, infrastructure, utilities, oil and gas, mining and marine industries.

Hercules Group of Companies is comprised of: Hercules SLR, Hercules Machining & Millwright Services, Spartan Industrial Marine, Stellar Industrial Sales and Wire Rope Atlantic.

We have the ability to provide any solution your business or project will need. Call us today for more information. 1-877-461-4876. Don’t forget to follow us on Twitter LinkedIn and Facebook for more news and upcoming events.