environment. Chemically active environments can affect the strength of the sling material in varying degrees, ranging from little to total degradation. Consult your sling manufacturer before using your web slings or roundslings in a chemically active environment.
• Synthetic slings should not be used at temperatures in excess of 194° F / 90° C, or at temperatures below -40°F / -40° C
• Use edge protection or barriers to prevent cutting of the synthetic sling when lifting materials with edges
• Always contact the manufacturer with any questions or concerns about maintaining, storing, and protecting your synthetic slings
#3
Stretched or Bent Links on Alloy Chain Slings
Alloy chain slings are some of the most over-used and abused pieces of rigging equipment in a facility. People tend to believe that because they’re made from alloy steel, they can lift the world with them and misuse and abuse them because they’re not as susceptible to damage as wire rope or synthetic slings. A huge misconception is that alloy chain slings
inherently have extra capacity. Terms like safety factor and design factor get thrown around, but just like any other lifting sling, a lift should never be made that exceeds the working load limit provided on the sling tag. However, when improperly used, chain damage typically falls into one of the following categories and critical damage will be obvious to a properly trained inspector. Tese categories include: • Cracks or breaks • Excessive wear, nicks, or gouges • Stretched links or fittings • Heat damage or weld splatter • Excessive pitting or corrosion • Chain or fittings don’t move freely
For example, overload normally causes chain bending or stretch in the individual chain links on a sling. Te overload can be the result of the load itself weighing more than the sling’s capacity.
Severe angles can also result in a sling being
overloaded. Alloy chain sling charts have rated capacities at 30°, 45°, and 60° angles. Te typical angle is 60°. Normally two, three, and four leg chains have three ratings for a specified number of pounds at 60°. Te sling identification tag also states the rated capacity for the specified sling angle. Be aware that sling angles greatly affect the tension on each leg of the sling. Te farther apart the legs of the sling are spread, the more tension there is on the sling legs. In applications involving high heat, the user must pay attention to the amount of direct heat that the chain sees. Often, direct heat results in the chain turning a blueish color. Te user should consult the chain manufacturer’s capacity reduction charts relating to heat. In addition, be aware of any damage caused by weld splatter or molten metal being splashed on the slings. In applications that involve lifting loads with
rough or sharp edges, wear pads should be used on unprotected corners—otherwise the chain is susceptible to nicks, gouges, and crushed or bent links.
#4
Broken Wires, Corrosion, and Deformation to Wire Rope
As a starting point, the same practices which apply to all “working” wire rope apply to wire rope which has been fabricated into a sling. Terefore, a good working knowledge of wire rope design and construction will not only be useful, but essential in conducting a wire rope sling inspection.
Tis being said, inspection of wire rope most often
uncovers broken wires, corrosion, and distortion of the rope’s original structure (kinking, crushing, or birdcaging). Any type of distortion that doesn’t straighten itself out when the rope or sling is put under load is cause for removal from service. Tis can also include wire rope sling eyes that have
been narrowed or stretched because they were paired with a shackle pin or crane hook that has an insufficient D/d ratio. When these deformities don’t come out under load—an inspector is going to fail that sling and recommend it comes out of service. OSHA does not provide clear guidelines on how to
make proper and adequate inspections of wire rope slings. It is up to the designated inspection personnel to know the requirements of the sling inspection standards, and to develop a comprehensive inspection protocol. Wire rope inspection should follow a systematic procedure:
• First, it is necessary that all parts of the sling are readily visible. Te sling should be laid out so every part is accessible.
• Next, the sling should be sufficiently cleaned of dirt and grease so wires and fittings are easily seen. Tis can usually be accomplished with a wire brush or rags.
28 NOVEMBER–DECEMBER 2018 WIRE ROPE EXCHANGE
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