Question

When performing a pre-operational inspection of a crane, what measurement indicates that a wire rope must be immediately removed from service?

Accepted Answer

During a pre-operational inspection of a crane, several measurements can indicate that a wire rope must be immediately removed from service. One critical measurement is the number of broken wires within a specific length of the rope. According to standards such as ASME B30.5, a wire rope must be removed from service if the number of visible broken wires exceeds certain limits within one rope lay. A rope lay is the distance it takes for one strand to make a complete revolution around the rope. The specific number of broken wires that triggers removal depends on the rope&#x27;s construction. For example, for a 6-strand rope, the rope must be removed if there are 6 or more broken wires in one rope lay. Another critical measurement is the amount of rope wear. Excessive wear reduces the rope&#x27;s diameter. If the rope diameter is reduced by more than a certain percentage of its original diameter (typically 5% to 10%, as specified by the manufacturer or applicable standards), it must be removed from service. Localized wear, such as flat spots or abrasion, is also cause for concern. Evidence of heat damage, such as discoloration or distortion of the wires, also necessitates immediate removal. Finally, any kinks, crushing, bird-caging (where the strands separate), or other forms of distortion indicate that the rope&#x27;s internal structure has been compromised and it must be removed. For example, if a crane&#x27;s wire rope shows seven broken wires within one rope lay, the wire rope is considered unsafe and needs immediate replacement, as it exceeds the allowable limit of six breaks. These measurements are essential for preventing wire rope failure and ensuring safe crane operation.

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When performing a pre-operational inspection of a crane, what measurement indicates that a wire rope must be immediately removed from service?

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