Wire Rope Inspection and Replacement Flashcards

A 6×37 classification wire rope with independent wire rope core (IWRC) is being inspected on a lattice boom crane. Over a length equal to 30 rope diameters, you count 8 broken wires in one strand and 5 broken wires distributed across two other strands. What is the correct removal-from-service determination under ASME B30.5?

Answer: Remove from service immediately — 8 broken wires in a single strand within 30 diameters meets the removal criterion regardless of total count

ASME B30.5 sets two thresholds for 6×37 class rope: 12 broken wires in any 30-diameter length (overall), OR 4 broken wires in a single strand within 30 diameters. Eight broken wires concentrated in one strand far exceeds the single-strand limit of 4, requiring immediate removal regardless of the total count or how the other strands look.

During a pre-shift inspection of a telescoping boom hydraulic crane, the inspector notices that the wire rope shows 'birdcaging' — the outer strands have pushed away from the core, creating a cage-like bulge. Which situation MOST commonly causes birdcaging, and what is the required action?

Answer: Caused by a sudden release of tension or shock loading; the rope must be removed from service immediately as the internal structure is permanently damaged

Birdcaging occurs when the lay of the rope is suddenly disrupted — typically by a sudden release of tension or shock load — causing the outer strands to spring outward. The internal geometry is permanently distorted; strands and wires no longer bear load uniformly. ASME B30.5 and most manufacturer guidelines classify birdcaging as an immediate removal-from-service condition. The rope cannot be repaired by re-laying, lubrication, or splicing.

A crane operator is spooling new 1-inch diameter 6×19 IWRC wire rope onto a grooved drum. The manufacturer's certificate states a minimum sheave/drum tread diameter (D) to rope diameter (d) ratio of 26:1 for normal service. The drum tread diameter measures 24 inches. Which statement BEST describes the situation?

Answer: Not acceptable — the 24:1 ratio is below the manufacturer's 26:1 minimum, increasing wire fatigue and requiring either a larger drum or a rope construction with a higher D/d tolerance

The D/d ratio determines the severity of bending stress each wire experiences as it passes over a drum or sheave. When the achieved ratio (24:1) falls below the manufacturer's certified minimum (26:1), wires undergo greater bending fatigue per cycle, shortening rope life and potentially causing premature failure. The correct response is to use a drum that meets or exceeds the 26:1 requirement, or to select a rope construction rated for a lower D/d ratio. ASME B30.5 requires adherence to the rope manufacturer's recommendations; the 18:1 figure cited in option A is a minimum floor, not a substitute for a manufacturer's higher requirement.

An inspector finds that a wire rope on a mobile crane has experienced 'valley breaks' — broken wires located at the contact points between adjacent strands rather than on the outer surface of the rope. Why are valley breaks particularly significant compared to crown breaks, and what does their presence indicate?

Answer: Valley breaks indicate inter-strand nicking and internal fatigue, often caused by a D/d ratio that is too small; they are more serious because they are hidden and the actual broken-wire count is likely higher than what is visible on the surface

Valley breaks occur at the contact points between adjacent strands — deep inside the rope's cross-section — as a result of inter-strand nicking and internal fatigue, frequently linked to operating over undersized sheaves or drums (low D/d ratio). Because they are hidden beneath the outer surface, an inspector sees only a fraction of the actual damage; many broken wires may exist that cannot be detected visually. Rope with valley breaks is typically much closer to catastrophic failure than the visible count suggests, making the condition more dangerous than surface crown breaks of similar visible count.

A wire rope end connection using a Flemish eye with a swaged sleeve is being evaluated for a critical lift. The swaged sleeve shows a visible crack running longitudinally along 40% of its length. The rope itself shows no broken wires and adequate diameter. What is the correct disposition?

Answer: Remove from service — a cracked swaged sleeve is a terminal condition; the sleeve cannot be repaired by re-swaging and the entire rope assembly must be replaced or a new end connection fabricated

A swaged sleeve that is cracked has lost its ability to grip and compress the rope wires uniformly, destroying the integrity of the end connection. The Flemish eye alone — without an intact, properly swaged sleeve — does not develop the full rated capacity of the assembly. ASME B30.5 and wire rope end-connection standards classify any cracked, deformed, or otherwise damaged swaged sleeve as a removal-from-service condition. Re-swaging a cracked sleeve or filling cracks with adhesive are not approved repair methods; the complete end connection must be replaced.

During a periodic inspection on a tower crane, the inspector measures the running rope's diameter at multiple points and finds a localized reduction of 4.5% from the nominal diameter in a section that passes repeatedly over a sheave. The rope is a 6×36 classification, rotation-resistant rope. Under ASME B30.3, what is the correct action?

Answer: Remove from service — a diameter reduction of 3% or more in rotation-resistant rope is a removal criterion under ASME B30.3, which applies stricter thresholds than general-purpose rope

ASME B30.3 (Tower Cranes) applies tighter removal criteria for rotation-resistant ropes than for conventional ropes because their complex multi-layer construction makes internal damage harder to detect and more sudden in progression. For rotation-resistant rope, ASME B30.3 specifies removal from service when diameter reduction reaches 3% of nominal — stricter than the 3% or 5% thresholds cited for conventional ropes elsewhere. A 4.5% localized reduction on a rotation-resistant rope clearly exceeds this limit and requires immediate removal regardless of visible broken wire count.