Rigging Inspection 101: Keeping Slings, Shackles, and Hardware Safe and Compliant

Heavy Lift. Engineered Execution. Apex Crane Service treats rigging the way a hospital treats sterile instruments — tagged, tracked, inspected, and pulled the moment something looks wrong. This guide walks through the inspection cadence, the rejection criteria, and the documentation that keeps your project audit-ready and your crew alive.

Rigging hardware serves as the critical connection between cranes and loads. Wire rope slings, synthetic slings, shackles, hooks, and spreader bars all require thorough inspection, maintenance, and documentation to ensure safe operations. Rigging inspection remains one of the most commonly cited OSHA deficiencies on construction sites — not because the rules are obscure, but because the discipline of doing it every shift, every time, is harder than it sounds.

When to Inspect Rigging

Before Each Use (Pre-Shift)

OSHA mandates visual inspection of rigging equipment before each use, looking for obvious damage, wear, or defects that could affect load capacity. This is the responsibility of the user — typically the rigger or competent person on site — and it happens every shift, on every piece, without exception.

Periodic Inspections

Detailed inspections at regular intervals based on usage frequency, service conditions, and manufacturer guidance. ASME B30.9 (Slings) generally requires periodic inspections at intervals not to exceed one year for normal service, more frequently for severe service. Periodic inspections must be documented and the records retained.

After Incident or Overload

Any rigging subjected to shock loading, overloading, or an incident must be removed immediately and inspected by qualified personnel before it returns to service. "It looked okay" is not an inspection — pull it, tag it, and have it evaluated.

What to Look For

Wire Rope Slings

Reject and remove from service if you see any of:

• Ten or more randomly distributed broken wires in one rope lay, or five broken wires in one strand in one rope lay
• Severe localized abrasion or scraping
• Kinking, crushing, bird-caging, or any damage resulting in distortion of the rope structure
• Evidence of heat damage or electrical arc strikes
• Corrosion, pitting, or significant loss of lubrication
• End fitting damage, displacement, or visible cracks
• Measurable rope diameter reduction (typically 5% of nominal diameter or more) indicating core failure
• Missing or illegible identification tag

Synthetic Web and Round Slings

• Cuts, tears, holes, snags, or punctures
• Broken or worn stitches in load-bearing splices
• Chemical damage or unusual discoloration
• UV degradation — chalky, stiff, or brittle webbing
• Melting, charring, or heat damage
• Knots tied in the sling body
• Missing or illegible identification tag — if you can't read the tag, you can't verify capacity
• Visible red warning yarns (in round slings, exposed core yarns are an immediate reject)

Shackles

• Deformation, elongation, or bending of the bow or pin
• Worn or damaged pin threads
• Missing or incorrect pins — never substitute a bolt for a shackle pin
• Corrosion or pitting on load-bearing surfaces
• Illegible capacity markings or manufacturer identification
• Side loading evidence (visible deformation from non-axial loading)

Hooks

• Throat opening increased more than 15% over original (use a go/no-go gauge)
• Twist of more than 10° from the plane of the unbent hook
• Cracks, gouges, or significant wear at the saddle
• Damaged, missing, or non-functioning safety latch
• Bearing surface wear of more than 10% of original section

Documentation Requirements

Each piece of rigging in service requires:

• Unique identification number or tag
• Clearly marked rated capacity
• Inspection history with dates and inspector identification
• Manufacturer certification or proof-load test documentation
• For sub-assemblies (spreader bars, lifting beams), engineering documentation and PE stamps as required

On ACS projects, this lives in a rigging register — a documented inventory of every piece of below-the-hook gear, its inspection history, and its status. When an auditor or owner's rep walks the site, that register answers most of the questions before they're asked.

Removal Criteria — Physically Remove, Don't Just Tag

Rigging that fails inspection must be immediately removed from service. Tagging out is not enough on a busy site. The rule we enforce:

The Cost of Doing This Right

Rigging is cheap compared to what it holds up. A sling that should have been pulled six months ago can cost a project a fatality, an OSHA investigation, and a year of insurance reverberations. A disciplined inspection program — pre-shift, periodic, post-incident, documented — is one of the lowest-cost, highest-leverage safety practices in the entire industry.