Hoist Rope Condition at the Pre-Operational Check
During the pre-operational check on a 25 t truck-mounted lattice-boom crane used for general yard work, you inspect the hoist rope: 6 x 36 wire strand, independent wire rope core, 20 mm nominal diameter, in service about five years with no rope certificate in the crane file. The last recorded third-party inspection of the crane was 14 months ago. You find the following: a measured diameter of 18.6 mm at the worst point, taken with a proper rope gauge; four broken wires in one outer strand within a 6d length at the drum crossover region; a section about 1.5 m from the dead end where the outer strands stand away from the core and the rope bulges; a sharp kink with a permanent bend near the sheave; light surface corrosion with no visible pitting. The supervisor wants to finish the day's work, which he describes as 'only a few light lifts'.
1. What are your actions after condemning the rope, and how do you answer the argument that the day's lifts are light?
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Land and secure the load, lower the hook to a safe position, and take the crane out of service. Isolate and tag the controls, or lock out the start, with a clear 'do not operate - hoist rope condemned' tag. Notify the supervisor in writing, photograph the findings, and record them in the crane log and the maintenance system. Do not cut the rope up for other uses and do not allow it to be re-fitted.
Fit a replacement rope from a supplier who provides a certificate for that rope, correct construction and diameter, with the manufacturer's installation instructions followed: correct end termination, pre-stretching or bedding-in, and re-checking the rope after the first few cycles. Then verify the limit switches and the reeving before returning the crane to service.
On the 'light lifts' argument: wire rope does not fail in proportion to the load on the day. The broken wires are at the drum crossover and the kink is near the sheave, which are exactly the areas of highest bending and abrasion. The conditions found are progressive and load-independent - corrosion, fatigue and core collapse continue while the crane sits. A rope with a birdcage and a kink can part under a light load or while the hook is being lowered empty, and the consequence is the same.
2. What does the missing certificate and the 14-month inspection gap tell you, and what should be done about the wider maintenance system?
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A running rope with no certificate has no verified construction, strength or history, which means no one can apply the correct discard table to it or show that the rope ever met the crane manufacturer's specification. The 14-month gap since the last recorded inspection means the periodic inspection regime is not being followed: whichever standard applies, periodic inspection by a competent person is required at defined intervals (commonly annual as a maximum, and more often for heavy duty, harsh environment or critical applications), alongside the operator's pre-use check each shift.
The wider problem is a maintenance management failure, not a single bad rope. The response should be: inspect every rope on site and pull the records for each; set up a register with rope identity, installation date, certificate, and inspection dates; define inspection intervals and the competent person who carries them out, plus criteria for what counts as a defect; and make sure the operator's pre-use check is recorded and has authority to stop the machine. A five-year-old rope with no paperwork and no inspection is the predictable output of a system that relies on someone noticing.