Crane and Rigging Safety Flashcards
6 cards from real CHST practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 6 Crane and Rigging Safety flashcards as text
What does the term 'Working Load Limit' (WLL) mean for rigging hardware?
Answer: The manufacturer-rated maximum load that rigging hardware is designed to handle in regular service
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.
Under OSHA 1926.251(c)(3), what is the required design factor for wire rope slings used in rigging operations?
Answer: 5:1 (the minimum breaking force must be at least 5 times the rated capacity)
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.
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?
Answer: Tension in each leg increases as the angle between the legs increases
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.
Under OSHA 1926.251, which condition requires a wire rope sling to be removed from service immediately?
Answer: Ten randomly distributed broken wires in one rope lay or five broken wires in one strand in one rope lay
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.
What is a 'critical lift plan,' and for which types of lifts is it required?
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
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.
Under OSHA 1926.1402, what must be done when a crane is set up on a surface where ground bearing capacity is uncertain?
Answer: A qualified person must determine the bearing capacity and, if inadequate, use mats, cribbing, or other support to distribute the crane's load safely
OSHA 1926.1402(b) requires a qualified person to evaluate ground conditions where cranes will be operated and to ensure the ground can safely support the crane's loads, using mats or cribbing as needed when ground is inadequate.