What is the rule of thumb formula to calculate the SWL of wire rope based on its diameter?

The formula to calculate the Safe Working Load (SWL) of wire rope based on its diameter utilizes the diameter in millimeters squared and then multiplies that value by a constant. In this case, the correct method applies the diameter in millimeters squared multiplied by 8.

This approach derives from the general understanding of wire rope properties, where SWL is often estimated based on the cross-sectional area of the rope. Squaring the diameter gives the area in square millimeters, which is a key factor in determining how much load the wire rope can safely handle. Multiplying by 8 provides a standard factor that takes into account the material properties and safety considerations relevant to wire rope usage.

The other options either misapply the relationship between diameter and load or use incorrect multipliers that do not accurately represent the typical safe working load calculations for wire rope.