Cranes, Derricks, Hoists, and Rigging Safety Flashcards
7 cards from real STSC practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Cranes, Derricks, Hoists, and Rigging Safety flashcards as text
When must a crane operator stop operations and contact a qualified person if the load line suddenly goes slack?
Answer: Immediately, as slack line may indicate a structural failure or two-blocking
A suddenly slack load line may signal two-blocking, a structural failure, or load contact with an obstruction, requiring immediate shutdown and inspection.
What is the purpose of a 'anti-two-block' device on a crane?
Answer: It automatically stops hoist motion before the hook block contacts the sheave
Anti-two-block devices automatically cut power to the hoist when the hook block nears the boom tip sheave, preventing catastrophic two-blocking.
Under OSHA 1926.1411, what action must be taken before using a synthetic web sling that has a melted or charred area?
Answer: Remove it from service immediately
Melted or charred areas on synthetic slings indicate heat damage that compromises structural integrity, requiring immediate removal from service.
A rigger notices that a wire rope sling has a kink that was removed by straightening. What is the correct action?
Answer: Remove the sling from service; kinking permanently damages wire rope
Once kinked, wire rope strands are permanently deformed and weakened at that point, making the sling unsafe even after straightening.
What minimum distance must a crane maintain from an unguarded energized power line rated at 50 kV under OSHA 1926.1408?
Answer: 10 feet
OSHA 1926.1408 requires a minimum 10-foot clearance from power lines up to 50 kV when no encroachment plan is in place.
When rigging a load with a basket hitch using a wire rope sling, what factor most significantly affects the sling's working load limit?
Answer: The horizontal angle of the sling legs relative to the load
As the sling angle decreases below 90°, the tension on each sling leg increases dramatically, reducing the effective working load limit.
Who is authorized to give a 'stop' signal to a crane operator under OSHA 29 CFR 1926.1419?
Answer: Any person who observes an unsafe condition
OSHA 1926.1419 states that any worker who observes a dangerous condition may give a stop signal, and the operator must honor it immediately.