CHST Crane and Rigging Safety 3

Question 1

What does the term 'Working Load Limit' (WLL) mean for rigging hardware?

Accepted Answer

The manufacturer-rated maximum load that rigging hardware is designed to handle in regular service

Answer

Working Load Limit (WLL) is the manufacturer-rated maximum load that a piece of rigging hardware can safely handle in regular service — it already incorporates a design safety factor.

Question 2

Under OSHA 1926.251(c)(3), what is the required design factor for wire rope slings used in rigging operations?

Accepted Answer

5:1 (the minimum breaking force must be at least 5 times the rated capacity)

Answer

OSHA 1926.251(c)(3) and ASME B30.9 require a design factor of 5:1 for wire rope slings — the rated capacity of the sling must not exceed one-fifth of the minimum breaking force of the wire rope used.

Question 3

As the angle between two sling legs increases (the legs spread farther apart), what happens to the tension in each sling leg for the same load?

Accepted Answer

Tension in each leg increases as the angle between the legs increases

Answer

As the sling angle (measured from horizontal) decreases or the included angle between legs increases, sling leg tension increases dramatically due to force vector geometry — this is known as the sling angle factor.

Question 4

Under OSHA 1926.251, which condition requires a wire rope sling to be removed from service immediately?

Accepted Answer

Ten randomly distributed broken wires in one rope lay or five broken wires in one strand in one rope lay

Answer

OSHA 1926.251(c)(10)(i) specifies that wire rope slings with ten randomly distributed broken wires in one rope lay, or five broken wires in one strand in one rope lay, must be removed from service.

Question 5

What is a 'critical lift plan,' and for which types of lifts is it required?

Accepted Answer

A documented analysis and plan required for lifts exceeding 75% of rated capacity, tandem lifts, or lifts over energized power lines or occupied areas

Answer

Critical lift plans are required for specific high-risk lift scenarios — typically lifts exceeding 75% of rated capacity, tandem or multi-crane lifts, and lifts over occupied structures or energized power lines.

CHST - Construction Health and Safety Technician Practice Test

CHST - Construction Health and Safety Technician Practice Test

CHST Crane and Rigging Safety 3