Rigging and Hoisting Flashcards

When inspecting wire rope, which condition requires immediate removal from service per CSA standards?

Answer: Six randomly distributed broken wires in one lay length

Six randomly distributed broken wires in one lay length is a standard rejection criterion indicating significant loss of rope integrity that makes continued use unsafe.

What does the D/d ratio describe in wire rope and sheave applications?

Answer: The ratio of sheave or drum diameter to wire rope diameter

The D/d ratio compares the diameter of the drum or sheave (D) to the diameter of the wire rope (d); a higher ratio reduces bending fatigue and extends rope service life.

A bolt-type shackle pin must always be:

Answer: Fully threaded in and secured with a cotter pin or moused with wire

The shackle pin must be fully inserted and properly secured to prevent it from unscrewing under load rotation, vibration, or dynamic forces.

How is a 'critical lift' defined in most Canadian provincial safety regulations?

Answer: A lift where failure could cause serious injury, death, or major property damage, typically requiring a written lift plan

A critical lift is defined by the potential severity of consequences if it fails; it typically requires a formal written lift plan and may require engineering sign-off.

What is 'two-blocking' in overhead crane operations?

Answer: The hook block rising until it contacts the upper head block, creating a sudden shock load

Two-blocking occurs when the hook block is hoisted until it strikes the upper head block, which can instantly snap the wire rope or cause catastrophic structural failure.

Which sling type is most suitable for lifting loads with sharp edges without using edge protection?

Answer: Alloy chain sling

Alloy chain slings are not susceptible to cutting from sharp load edges the way synthetic or wire rope slings are, making them the preferred choice for angular loads.

Before any lift, what is the single most critical pre-lift check a millwright rigger must perform?

Answer: Inspecting all rigging equipment for defects and confirming the load weight

Knowing the exact load weight and verifying all rigging is free of defects ensures the lift stays within rated capacities and that no compromised equipment is used.