chain slings, synthetic slings, wire rope slings, below- the-hook devices—all of these items are required to have identification tags or markings that provide the end user with the capacity or Working Load Limit (WLL). ASME has specific requirements for what identification or markings need to be on each type of device—but at the minimum, these tag requirements help the end-user understand the following:
• Manufacturer/serial number for traceability • Product specifications—including material, diameter, weight, design category
• Working load limit • Lifting capacities for different sling hitches and sling angles
Te problem with rigging equipment is that its most commonly used in an environment that’s dirty, dusty, greasy, grimy, or just flat-out abusive. For slings, this usually means that they’re getting damaged, ripped off, covered in dirt or grease, or smudged to the point they’re no longer legible. Once a tag or identification is illegible or removed, the sling is no longer able to be used and must be removed from service. If you’re having problems keeping tags on slings,
or your gear is getting scuffed or marked to the point where the tag or rated load marking are no longer legible, you have to ask yourself a couple of questions:
Are you selecting the right type of gear for this type of lift? If you’re using synthetic slings and your tags keep getting ripped off, maybe it’s time to switch to a more durable sling tag, or to a different style sling like wire rope slings, or alloy chain slings.
Are you using best practices when rigging the load? If your tag keeps getting snagged on something and gets ripped off, are you rigging the load properly? Attach the end of the sling with the tag to the crane hook so it’s less likely to get scrubbed through something or pulled off during the course of a lift. Also, make sure your riggers and crane operators are properly trained and are using best practices when rigging a load.
#2
Damage to Synthetic Slings (Cuts, Tears, UV Degradation,
Chemical Exposure)
A synthetic lifting sling may be the best choice for your overhead lift and can provide the flexibility, strength, and support you need when moving material through your facility or across your job site. However, you’ll have to give special considerations to the operating environment, stretch under load, and the possibility of the load causing cuts or abrasion to the sling. Synthetic web slings and roundslings—made from nylon or polyester—are more susceptible to damage from environmental factors like extreme temperatures,
prolonged UV exposure, and chemically active environments. Tey’re also not as durable as steel wire rope slings or alloy chain slings when it comes to abrasion and cut resistance. Synthetic slings have a relatively low heat-resistance
and are not recommended for use in high-heat applications. However, special high-heat resistant slings are available from certain manufacturers Special considerations must be made when selecting a synthetic sling to be used in chemical applications. Nylon and polyester slings have different resistance characteristics to acidic and alkaline environments Corner protectors or edge guards should be used
to protect against cuts and tears If there’s any evidence of heat damage, UV damage, rips, tears, punctures, abrasion, or worn or broken stitching, the sling should be removed from service and properly disposed of to discourage further use. Another problem we see is that the end-user may have
a solvent tank that they use to remove grease or grime from their equipment or machined parts. Tey’ll throw greasy web slings or roundslings into that solvent tank to clean them off and mistakenly think they’re taking care of their rigging gear. You can’t do this with a synthetic sling—the chemicals in those solvent tanks will degrade the nylon or polyester fibers in that sling and over time, this affects the integrity of that lifting sling. Te best way to help extend the life of a synthetic
roundsling, and help to ensure that it stays in service, is to properly maintain it during and in-between each use. Take care of your gear and your gear will take care of you—it’s that simple. Here are some best practices to keep your synthetic slings in great condition:
• Keep your slings off of the ground and store them in a cool, dry, and dark environment
• Avoid continued exposure to extreme hot or cold temperatures and store them away from direct sunlight and UV exposure to prevent loss of strength
• Keep your slings clean. Continual exposure to dust, dirt, and moisture can degrade the materials over time and shorten the life expectancy of the product.
• Do not store your synthetic slings in a chemically active WIRE ROPE EXCHANGE
NOVEMBER–DECEMBER 2018 27
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