WTT Rigging & Lifting Operations 1 — Questions and Answers
Question 1: What does WLL stand for in the context of rigging equipment?
- Working Load Limit (Correct answer)
- Wire Load Length
- Weight Lift Level
- Weighted Leverage Limit
Correct answer: Working Load Limit
WLL (Working Load Limit) is the maximum load that rigging equipment is rated to handle under normal conditions.
Question 2: When inspecting wire rope, what is the typical maximum allowable number of broken wires in one rope lay length before it must be removed from service?
- 6 broken wires in one rope lay (Correct answer)
- 10% of total wires in any strand
- 20 broken wires across the entire rope
- Any visible broken wire
Correct answer: 6 broken wires in one rope lay
Industry standards (ASME B30.2) generally require removing wire rope from service if 6 or more broken wires are found within one rope lay length.
Question 3: What is the primary purpose of a rigging plan before lifting heavy wind turbine components such as a nacelle?
- To document the lift for OSHA recordkeeping only
- To identify hazards, assign responsibilities, and define lift procedures before work begins (Correct answer)
- To estimate the cost of the lifting operation
- To determine whether a crane rental is needed
Correct answer: To identify hazards, assign responsibilities, and define lift procedures before work begins
A rigging plan proactively identifies hazards, defines roles, specifies equipment, and establishes procedures to ensure a safe lift.
Question 4: Which sling configuration provides the LOWEST effective working load limit relative to the sling's rated capacity?
- Vertical hitch
- Basket hitch
- Choker hitch (Correct answer)
- Double-wrap basket hitch
Correct answer: Choker hitch
A choker hitch reduces the sling's effective WLL to approximately 75% of its vertical rating due to the bend angle and friction created at the choke point.
Question 5: What color identifies a synthetic web sling with a 1-ton (2,000 lb) vertical working load limit per the Web Sling and Tiedown Association (WSTDA) standard?
- Red
- Green (Correct answer)
- Purple
- Gray
Correct answer: Green
WSTDA color coding assigns green to synthetic web slings rated for a 1-ton (2,000 lb) vertical WLL.
Question 6: When rigging with a two-leg bridle sling, what included angle between the legs is generally recommended to maintain safe load distribution?
- 90 degrees or less
- 60 degrees or less
- 120 degrees or less (Correct answer)
- 45 degrees or less
Correct answer: 120 degrees or less
ASME and industry guidelines recommend keeping the included angle between bridle sling legs at 120 degrees or less to prevent excessive tension on each leg.
Question 7: What is the purpose of a shackle's safety pin or bolt when used in a lifting application?
- It increases the shackle's working load limit
- It prevents the shackle bow from rotating during the lift
- It secures the screw pin and prevents it from backing out under load (Correct answer)
- It provides a visual indicator that the shackle is rated for lifting
Correct answer: It secures the screw pin and prevents it from backing out under load
The safety pin or mousing wire through a screw-pin shackle prevents the pin from inadvertently backing out or rotating loose during a dynamic lift.
WTT Rigging & Lifting Operations 1
What does WLL stand for in the context of rigging equipment?