Wire Rope Inspection and Discard Criteria Schema for AI Agents — ASME B30.2: 6 Broken Wires Per Lay, 3 Per Strand, Kink/Bird-Cage/Core Protrusion, D/d Sheave Ratio, and Rotation-Resistant Internal Damage

Wire rope that has reached a broken-wire discard criterion can sometimes be shortened to remove the damaged section and the undamaged tail reused — but only after careful consideration of several factors. First, the total remaining length must still be sufficient for the lift — the wire rope must reach from the drum through all sheaves to the load with the required dead wraps on the drum. ASME B30.2 requires a minimum of two dead wraps on the drum at maximum lift height; if shortening the rope reduces total length below the required minimum for the lift, the rope cannot be reused. Second, if the damage was caused by a sheave groove problem (undersized groove causing wire cutting), kink, or corrosion, the remaining rope may have the same damage in progress elsewhere on the rope — replacing the damaged section without addressing the root cause allows the problem to recur at a different location. Third, after shortening, the new end must be properly terminated with an approved end fitting (spelter socket, swaged socket, or properly installed rope clips per ASME B30.26). Fourth, the inspection after shortening should cover the full length of the remaining rope — not just the area that was obviously damaged. Wire rope that has reached removal criteria due to general wear (distributed broken wires throughout the rope) should be replaced in full, not shortened. Rope that has one localized damage zone from a single incident may be a candidate for shortening after root-cause correction.

ASME B30.2 applies to overhead and gantry cranes — it covers the running rope on crane hoist mechanisms, bridges, trolleys, and pendant controls. ASME B30.9 applies to slings — rigging hardware used to attach the load to the crane hook. Wire rope slings have different construction, service modes, and discard criteria than running rope. B30.9 sling discard criteria include: 10 randomly distributed broken wires in one rope lay (more permissive than B30.2 because slings have multiple legs and each leg is typically discarded as a set); 5 broken wires in one strand in one lay; evidence of kinking, birdcaging, heat damage, or corrosion. The key practical difference: wire rope running rope wraps around multiple sheaves under cyclic bending stress — it accumulates fatigue over thousands of cycles. Wire rope slings are typically used in tension only (no bending over small sheaves in service) and their failure mode is primarily corrosion, abrasion, and overloading. Additionally, ASME B30.5 covers mobile cranes (truck and crawler cranes), ASME B30.22 covers articulating boom cranes (knuckle boom cranes), and ASME B30.23 covers personnel lifts — each has slightly different wire rope requirements. Encode wire_rope.asme_b30_standard to specify which standard's criteria apply to the specific product application.

Magnetic flux leakage (MFL) wire rope testing is a non-destructive evaluation (NDE) method that detects both surface and internal wire rope defects. A strong permanent magnet or electromagnet saturates a section of wire rope with magnetic flux. Where the rope is uniform, flux flows through the rope with minimal leakage to the surface. Where there is a broken wire, a corrosion pit, or a change in metallic cross-section (wear or deformation), some flux leaks out of the rope surface and is detected by Hall-effect sensors or induction coils. Surface defects (broken outer wires, surface corrosion) and internal defects (broken inner wires, inner corrosion, strand core failures) both create leakage signals — the signal strength and shape help distinguish between them. MFL does not require disassembly and can be performed while the rope is in service on the crane. ASME B30.2 does not explicitly require MFL for standard 6-strand rope in good visual inspection condition — however, when visual inspection results raise questions about internal condition, or for rotation-resistant ropes where outer wire count is unreliable, MFL is the appropriate next step. API RP 9B (Wire Rope Inspection for Oilfield Hoisting Equipment) requires MFL at defined intervals for offshore crane wire rope. Facilities with rotation-resistant rope on critical lifts should establish MFL inspection intervals (typically every 6 months under normal use) based on a documented wire rope inspection plan. Encode wire_rope.mfl_inspection_recommended = true on rotation-resistant and compacted-strand ropes where visual inspection alone is insufficient to assess internal condition.