433A Rigging and Hoisting 2 — Questions and Answers
Question 1: When inspecting wire rope, which condition requires immediate removal from service per CSA standards?
- Minor surface rust with no visible pitting
- Six randomly distributed broken wires in one lay length (Correct answer)
- Slight surface dryness requiring lubrication
- A slight kink that straightens easily by hand
Correct 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.
Question 2: What does the D/d ratio describe in wire rope and sheave applications?
- The ratio of sheave or drum diameter to wire rope diameter (Correct answer)
- The ratio of dead load to dynamic load
- The ratio of design load to rated datum load
- The ratio of deflection to rope displacement
Correct 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.
Question 3: A bolt-type shackle pin must always be:
- Greased and left finger-tight to permit load rotation
- Fully threaded in then backed off one-quarter turn
- Fully threaded in and secured with a cotter pin or moused with wire (Correct answer)
- Replaced with any bolt of the same diameter if the original is unavailable
Correct 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.
Question 4: How is a 'critical lift' defined in most Canadian provincial safety regulations?
- Any lift involving a load exceeding 1,000 kg
- A lift where failure could cause serious injury, death, or major property damage, typically requiring a written lift plan (Correct answer)
- Any lift performed within 3 metres of energized electrical equipment
- A lift requiring more than two rigging slings
Correct 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.
Question 5: What is 'two-blocking' in overhead crane operations?
- Using two separate crane hooks for a single lift
- The hook block rising until it contacts the upper head block, creating a sudden shock load (Correct answer)
- Using two wire rope slings as the primary rigging
- Blocking a load from both sides using timber cribbing
Correct 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.
Question 6: Which sling type is most suitable for lifting loads with sharp edges without using edge protection?
- Synthetic web sling
- Wire rope sling
- Alloy chain sling (Correct answer)
- Round synthetic sling
Correct 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.
Question 7: Before any lift, what is the single most critical pre-lift check a millwright rigger must perform?
- Confirming the weather forecast shows wind speeds under 40 km/h
- Verifying the crane's fuel or hydraulic fluid level
- Inspecting all rigging equipment for defects and confirming the load weight (Correct answer)
- Ensuring the crane operator holds a valid provincial operator certificate
Correct 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.
433A Rigging and Hoisting 2
When inspecting wire rope, which condition requires immediate removal from service per CSA standards?