433A Rigging and Hoisting 1 — Questions and Answers
Question 1: What does WLL stand for when marked on rigging equipment?
- Weight Loading Limitation
- Working Load Limit (Correct answer)
- Wire Load Level
- Winding Load Leverage
Correct answer: Working Load Limit
WLL stands for Working Load Limit, the maximum load a piece of rigging equipment is rated to lift under normal service conditions.
Question 2: Which hitch configuration provides the highest effective WLL when using a single-leg sling?
- Choker hitch
- Vertical hitch
- Basket hitch (Correct answer)
- Double wrap choker hitch
Correct answer: Basket hitch
A basket hitch supports the load on both sides of the sling, effectively doubling the rated capacity compared to a vertical (straight) hitch.
Question 3: When two sling legs form a 120° included angle, what is the approximate tension in each leg relative to the total load weight?
- Half the total load weight
- 0.87 times the total load weight
- Equal to the total load weight (Correct answer)
- Twice the total load weight
Correct answer: Equal to the total load weight
At a 120° included angle each leg is 60° from vertical, so tension per leg = W/(2 × cos 60°) = W/(2 × 0.5) = W, equalling the full load weight.
Question 4: What is the minimum number of wire rope clips (Crosby-type) required when forming an eye in 1/2" (13 mm) diameter wire rope?
- 2
- 3 (Correct answer)
- 4
- 5
Correct answer: 3
CSA and manufacturer standards require a minimum of 3 wire rope clips for 1/2" rope to achieve the required connection efficiency.
Question 5: A synthetic web sling whose red warning core is visible through the outer jacket should be:
- Used only for light lifts under 500 kg
- Tagged and monitored but kept in service
- Removed from service immediately (Correct answer)
- Repaired with industrial tape before reuse
Correct answer: Removed from service immediately
An exposed red warning core indicates the sling outer jacket is critically worn; the sling must be removed from service immediately per CSA Z150 requirements.
Question 6: What is the primary purpose of attaching a tagline to a suspended load?
- To provide a secondary load path if the main sling fails
- To control the load's rotation and prevent uncontrolled swinging (Correct answer)
- To attach the load to the crane hook
- To measure the weight of the suspended load
Correct answer: To control the load's rotation and prevent uncontrolled swinging
A tagline allows workers to guide and stabilise a suspended load from a safe distance without being in the load's fall zone.
Question 7: According to CSA standards, what is the maximum recommended included angle between two sling legs for most rigging lifts?
- 60°
- 90°
- 120° (Correct answer)
- 150°
Correct answer: 120°
CSA and ASME B30 standards recommend a maximum included angle of 120° between sling legs; beyond this the leg tension increases to dangerous levels.
433A Rigging and Hoisting 1
What does WLL stand for when marked on rigging equipment?