Wire-Rope Sling Inspection and Removal

Wire-Rope Sling Inspection and Removal

Identify and lay out the sling

Confirm the required identification and rated capacities before handling the rope as a candidate for use. Lay the sling where the entire length, eyes, sleeves, thimbles, sockets, and fittings can be examined. Wear appropriate hand protection; broken wires can puncture skin. Rotate and flex the rope gently to expose valleys and hidden areas without creating a kink.

Wire-rope construction includes wires, strands, and a core. A rope lay is the distance in which a strand makes one complete revolution around the core. Broken-wire counts are made within that defined length, not over the entire sling.

Exact OSHA broken-wire criteria

Under OSHA 1910.184, a wire-rope sling must be removed when it has:

• ten randomly distributed broken wires in one rope lay; or
• five broken wires in one strand in one rope lay.

The threshold is reached at those counts; it is not permission for “ten plus one.” Mark the lay boundary, count carefully, and inspect near fittings where breaks can concentrate. Apply any more restrictive current B30.9 or manufacturer criterion to the exact sling construction and location.

Wear and deformation

OSHA also removes a sling for wear or scraping of one-third the original diameter of outside individual wires. This is an individual-wire criterion, not a universal statement that the whole rope may lose 5% of nominal diameter. Current standards and manufacturers can have additional diameter or localized-damage rules; use the criterion that actually applies.

Remove the sling for kinking, crushing, birdcaging, or other distortion of the rope structure. A kink permanently displaces wires and strands. Crushing flattens the rope and disrupts load sharing. Birdcaging separates strands from the core. Other warning signs include core protrusion, strand displacement, localized increase or reduction in diameter, and severe abrasion.

Do not straighten a kink with a hammer, twist a birdcage closed, or hide a crushed area in a hitch.

Heat, corrosion, and electrical damage

Heat damage can appear as discoloration, fused lubricant, scale, or evidence of welding or torch contact. OSHA requires permanent removal of fiber-core wire-rope slings exposed above 200°F. For slings with nonfiber cores, use above 400°F or below minus 60°F must follow the sling manufacturer's recommendations.

Do not restate 400°F as a universal absolute maximum for every nonfiber sling; it is the point at which OSHA requires manufacturer direction. Arc strikes and weld spatter can damage wires locally and create severe stress concentrations.

Light surface oxidation and severe corrosion are not equivalent, but corrosion must be evaluated over the full rope, including inside valleys and at sleeves. Pitting, stiffness, loss of metallic area, or broken wires can require removal. Cleaning must not mask damage or use a chemical that attacks the rope or lubricant.

Eyes and end attachments

Inspect thimbles for distortion, wear, and proper seating. Examine mechanical sleeves for cracks, slipping, severe wear, deformation, or pulled strands. Check sockets, swaged fittings, hooks, and links for the applicable defects and identity. A damaged or worn end attachment is an OSHA removal condition.

Look for evidence that the rope has moved at a sleeve or socket: displaced markings, changed tail length, pulled strands, or an eye that no longer retains its shape. Do not field-weld, hammer, or press a termination.

OSHA construction rules do not allow wire-rope clips or knots to form eyes in wire-rope bridles, slings, or bull wires. Where clips are allowed for a different application, the exact OSHA table and manufacturer instructions control number, spacing, torque, and orientation.

Rotation, bends, and use

Avoid allowing a sling to twist, kink, or rotate in a way that opens the rope. Keep eyes seated on adequately sized, smooth bearing surfaces. A small pin or sharp bend reduces capacity according to the sling manufacturer; do not apply a generic D/d efficiency chart as if it were the tagged WLL.

Protect wire rope from edges that can sever wires or create a severe bend. Do not shock load or drag the sling. Keep hands away as the rope seats; wire rope can roll suddenly into position.

Inspection outcome

If a removal criterion is present, take the sling out of service and identify or segregate it so it cannot be used accidentally. “Derate 10%” is not a repair. Repair is limited to what the standard and manufacturer authorize and must be performed by an appropriate source with required proof testing and new identification.

Record inspections when the controlling rule or employer program requires them. A pre-use check does not replace periodic inspection, and a periodic record does not excuse checking after an incident, suspected overload, heat exposure, or visible change.

For the exam, connect the observation to its exact rule: count broken wires within one lay, distinguish wire wear from whole-rope diameter, identify structural distortion, and inspect every termination. If the facts meet a criterion, remove the sling—do not negotiate with the defect.