10.3 Roundslings, Core Protection and Performance Fibers
Key Takeaways
Read the tag; cover color is not a universal U.S. WLL code.
The ordinary cover is not a rated cut protector.
A damaged or exposed core requires removal under the applicable criteria.
Distinguish the core from its cover
A roundsling contains continuous load-bearing fibers enclosed by a protective cover. For an ordinary polyester roundsling, the core carries the rated tensile load and the cover protects it. A cover that still looks present does not prove the internal fibers are sound, and a damaged cover can expose the core to cutting or contamination.
Roundslings can be flexible and light for their capacity, allowing contact around some irregular shapes. They still require correct bends, compatible hardware and suitable protection. The cover can bunch, and concentrated contact can damage core fibers. Do not treat softness as evidence that all contact conditions are permitted.
Identify the product material and rated assembly. Polyester and high-performance fiber roundslings can have different heat, chemical, bend and inspection requirements. High-modulus polyethylene, aramid and other fibers are not interchangeable. Use the actual manufacturer’s instructions rather than combining properties from several materials into one imaginary product.
Read tags rather than colors
Color coding is used by some manufacturers or standards, but it is not a universal U.S. capacity system. A purple, green or yellow cover does not establish a particular rating unless the relevant product identification and standard support it. The legible tag and documentation establish WLL, material and applicable hitches.
| Identification item | What it establishes |
|---|---|
| Manufacturer and product | Which instructions apply |
| Material | Applicable exposure and mechanical limitations |
| Rated hitch values | Capacity for the described arrangement |
| Size or other assembly designation | Traceable product selection |
| Inspection features | Which product-specific indicators to evaluate |
A missing or unreadable required tag requires removal from service under the applicable sling requirements. Field guessing based on cover color or diameter is not retagging. Authorized identification restoration requires traceable information and the manufacturer or other permitted process; proof testing is not automatically required in every retagging situation, nor does a test alone reveal an unknown fiber.
Use the correct contact geometry
Check the minimum bearing dimensions, bend requirements and hardware fit specified for the sling. A high-capacity roundsling in a small shackle may not have enough bearing width or room to seat. Stacking several textile slings in one hook can create crowding, crossed load paths or contact with the latch.
Use approved connectors or a suitable collector arrangement when necessary. A fitting’s steel capacity does not establish textile compatibility. Manufacturer instructions may address permitted overlap or folding; the Level II practical course’s overlap scoring treatment is not a universal field installation rule.
For choker and basket use, apply the actual hitch rating and angle conditions. A nominal basket value can assume specified bends and orientation. If a table already includes a sling angle, do not apply the same angle reduction twice. If the lower parts are inclined, calculate or look up the applicable condition rather than assuming both remain vertical.
Protection is more than a sleeve
The ordinary roundsling cover is not a rated cut protector. Add protection selected for the actual edge, force and movement. An abrasion sleeve may protect against rubbing but not a severe edge under load. Ensure protectors remain in position throughout any rotation or sliding contact.
An internal inspection or telltale feature is product specific. Some products have indicators for certain damage modes; others do not. An unchanged indicator does not prove the entire core is undamaged by every exposure. Follow the inspection criteria for the actual product, including any limitations on using the indicator.
Remove suspect equipment
Inspect for cover cuts or tears, exposed core, knots, heat damage, chemical damage, unusual stiffness, lumps, uneven core distribution or damaged fittings as specified. For ordinary polyester roundslings, exposed or damaged core fibers are a removal condition. The manufacturer determines whether a particular cover repair is permitted; field core repair is not an acceptable method.
Do not assume a numerical percentage of visible cover damage measures remaining strength. The load-bearing material is internal and damage may be localized. Remove the sling and keep it separated pending authorized disposition. Cutting or destroying rejected gear can be appropriate under the disposal process, but evaluation and authorized repair should not be confused with automatic destruction of every removed item.
Application scenario
A roundsling with a readable 20,000-lb applicable rating is proposed for a 15,000-lb leg tension. During inspection, the cover has a cut exposing core fibers. The capacity comparison cannot override the removal criterion. Replacing it with another approved sound sling also requires verifying the same material, hitch and bearing compatibility.
When storing, avoid hooks, edges or surfaces that can cut the cover; protect from harmful exposure and keep identification visible. Handle high-capacity slings with suitable care even when they are light enough to carry easily. Their portability does not make hidden core damage less consequential.
Sources: CCO sling reference materials, CMCO rigging resources.
A roundsling has adequate tagged capacity but a cover cut exposes its core. What is the correct decision?
Use it because tagged capacity is high
Remove it from service under the applicable inspection criteria
Tape the cover and continue
Reduce WLL by a guessed percentage
Sections you finish are checked off in the contents.