Wire rope on hoists in regular service should be visually inspected daily by the operator. If the hoist is used in multiple-shift operations, wire rope should be visually inspected by the operator at the start of each shift. The daily inspection by the operator is for visual damage to the wire rope. Such damage includes excessive broken wires and wear, broken strands, kinks, birdcaging, or damage resulting in deformation of the wire rope structure. When visual damage is present, the operator shall report such damage to the supervisor, and shall not operate the hoist until a more detailed inspection is performed to determine that the wire rope can be used, or the wire rope is replaced. Detailed inspection procedures are outlined below. These procedures also apply to scheduled frequent and periodic inspections.
Wire rope consists of a core, strands, and wires that comprise a strand as shown in Figure 8 below. The diameter of the wire rope is the diameter of a circle that would enclose the wire-rope strands. Correct and incorrect methods of measuring wire-rope diameter are shown in Figure 9 below. The term one rope lay refers to the length of wire rope assembly wherein one strand completely wraps 360° around the wire-rope assembly.
Wire rope items to be included for inspection during scheduled frequent and periodic inspections; or if the daily visual inspection by the operator indicates a more detailed inspection is required; are as follows:
- Rope distortion such as kinking, crushing, unstranding, birdcaging, main strand displacement, or core protrusion.
- General corrosion.
- Broken or cut strands.
- Number, distribution, and type of visible broken or cut wires.
- Reduction of rope diameter due to loss of core support, internal or external corrosion, or wear of outer wires.
- Damage from heat.
- Corroded or broken wires at end connections.
- Corroded, cracked, bent, worn, damaged, or improperly applied end connections.
- Wire rope pull through of end connection.
- Tightening of clamping-type end connections. Checking torque of bolts of end connections for clamps that recommend a specified torque on the clamp bolts.
- Rope lubrication, if recommended.