STSC Cranes, Derricks, Hoists, and Rigging Safety 4

Question 1

When must a crane operator stop operations and contact a qualified person if the load line suddenly goes slack?

Accepted Answer

Immediately, as slack line may indicate a structural failure or two-blocking

Answer

A suddenly slack load line may signal two-blocking, a structural failure, or load contact with an obstruction, requiring immediate shutdown and inspection.

Question 2

What is the purpose of a 'anti-two-block' device on a crane?

Accepted Answer

It automatically stops hoist motion before the hook block contacts the sheave

Answer

Anti-two-block devices automatically cut power to the hoist when the hook block nears the boom tip sheave, preventing catastrophic two-blocking.

Question 3

Under OSHA 1926.1411, what action must be taken before using a synthetic web sling that has a melted or charred area?

Accepted Answer

Remove it from service immediately

Answer

Melted or charred areas on synthetic slings indicate heat damage that compromises structural integrity, requiring immediate removal from service.

Question 4

A rigger notices that a wire rope sling has a kink that was removed by straightening. What is the correct action?

Accepted Answer

Remove the sling from service; kinking permanently damages wire rope

Answer

Once kinked, wire rope strands are permanently deformed and weakened at that point, making the sling unsafe even after straightening.

Question 5

What minimum distance must a crane maintain from an unguarded energized power line rated at 50 kV under OSHA 1926.1408?

Accepted Answer

10 feet

Answer

OSHA 1926.1408 requires a minimum 10-foot clearance from power lines up to 50 kV when no encroachment plan is in place.

(STSC) Safety Trained Supervisor Construction Practice Test

(STSC) Safety Trained Supervisor Construction Practice Test

STSC Cranes, Derricks, Hoists, and Rigging Safety 4