Free STSC Cranes, Derricks, Hoists, and Rigging Safety Questions and Answers 1 — Questions and Answers
Question 1: A signal person is required for a crane lift when:
- The load exceeds 50% of the crane's capacity
- The point of operation is not in full view of the operator (Correct answer)
- The lift is being performed at night
- The lift involves more than two workers
Correct answer: The point of operation is not in full view of the operator
OSHA 1926.1419(a) requires a signal person when the point of operation is not in full view of the operator, when the operator's view is obstructed in the direction the equipment is traveling, or when either the operator or the person handling the load determines that a signal person is needed. This ensures constant communication and hazard awareness during the lift.
Question 2: What is the minimum required clearance from a 50kV power line when operating a crane?
- 5 feet
- 10 feet (Correct answer)
- 15 feet
- 20 feet
Correct answer: 10 feet
According to OSHA 1926.1408 Table A, for power lines with a voltage up to 50kV, the minimum clearance distance that must be maintained is 10 feet. This distance increases as the voltage of the power line increases. Maintaining this 'circle of safety' is a fundamental rule to prevent electrical arcing and electrocution.
Question 3: Who is primarily responsible for ensuring the ground conditions at a construction site are firm, drained, and graded sufficiently to support the crane?
- The crane operator
- The crane rental company
- The controlling entity (Correct answer)
- The lift director
Correct answer: The controlling entity
OSHA 1926.1402(b) states that the controlling entity (e.g., the general contractor) has the primary responsibility to provide adequate ground conditions. The crane operator, however, retains the authority to stop work if they believe the ground conditions are unsafe.
Question 4: How often must rigging equipment, such as slings and shackles, be inspected?
- Once per week by a qualified person
- Prior to use on each shift (Correct answer)
- Only when a critical lift is planned
- Annually by a third-party inspector
Correct answer: Prior to use on each shift
OSHA 1926.251(a)(1) requires that rigging equipment be inspected prior to use on each shift and as necessary during its use to ensure it is safe. Any equipment found to be defective must be immediately removed from service. This frequent inspection is critical for preventing rigging failure.
Question 5: What is the primary purpose of using tag lines during a lift?
- To add extra support to the rigging
- To measure the height of the lift
- To control the load and prevent rotation (Correct answer)
- To signal the crane operator
Correct answer: To control the load and prevent rotation
Tag lines are ropes attached to a load that are used by ground personnel to control the load's movement. Their main purpose is to prevent the load from swinging or rotating uncontrollably, which could cause it to strike workers or objects, especially in windy conditions.
Question 6: A lift is generally considered a 'critical lift' and requires a detailed lift plan when it involves:
- Any load heavier than 1,000 pounds
- A load that exceeds 75% of the crane's rated capacity (Correct answer)
- Any lift performed after sunset
- A load that must be moved more than 100 feet horizontally
Correct answer: A load that exceeds 75% of the crane's rated capacity
While OSHA does not have a strict definition, industry best practice defines a critical lift as one that carries an increased level of risk. This includes lifting personnel, using multiple cranes, lifting over sensitive areas, or lifting a load that exceeds a high percentage (e.g., 75%) of the crane's rated capacity. Such lifts require more extensive planning and oversight.
Free STSC Cranes, Derricks, Hoists, and Rigging Safety Questions and Answers 1
A signal person is required for a crane lift when: