NCCER Crane Site Operations & Hazard Recognition 3 — Questions and Answers
Question 1: What is the main purpose of using outrigger pads (cribbing) under a crane's outrigger floats?
- To raise the crane for better visibility
- To distribute the outrigger load over a larger area of ground (Correct answer)
- To prevent the outriggers from rusting
- To level the crane electronically
Correct answer: To distribute the outrigger load over a larger area of ground
Outrigger pads spread the point load of the outrigger float across a wider surface area to reduce ground bearing pressure.
Question 2: A crane operator receives conflicting hand signals from two workers on the ground. What should the operator do?
- Follow the signal from the worker closest to the load
- Stop operations and clarify who the designated signalperson is (Correct answer)
- Use the most conservative signal given
- Continue at reduced speed and pick the safest action
Correct answer: Stop operations and clarify who the designated signalperson is
Only one designated signalperson may direct crane movements; the operator must stop when signals are unclear or conflicting.
Question 3: Which type of underground utility poses the greatest immediate threat if struck by outriggers or crane movement?
- Fiber optic cable
- Gas pipeline (Correct answer)
- Water main
- Storm drainage pipe
Correct answer: Gas pipeline
Striking a gas pipeline can cause an immediate explosion or fire, creating a life-threatening emergency.
Question 4: What does a 'two-block' condition mean in crane operations?
- Using two independent load blocks on a single hook
- The load block contacts the boom tip or sheaves, creating a hazardous overload (Correct answer)
- Operating with two separate loads simultaneously
- When the crane reaches 50% of its rated capacity
Correct answer: The load block contacts the boom tip or sheaves, creating a hazardous overload
Two-blocking occurs when the load block runs up and contacts the boom head, which can break the hoist line or damage the crane.
Question 5: When setting up a crane near an excavation or trench, what is the primary concern?
- Dust from the excavation damaging the engine
- Potential for trench wall collapse under crane and outrigger loads (Correct answer)
- Obstruction of the operator's sight lines
- Interference with excavation equipment below
Correct answer: Potential for trench wall collapse under crane and outrigger loads
Crane loads near excavations can cause trench wall or shoring failure, collapsing the excavation and tipping the crane.
Question 6: During a lift, the load starts swinging uncontrollably. What is the correct immediate response?
- Boom down to lower the load quickly
- Stop all motion and allow the load to dampen naturally before resuming (Correct answer)
- Speed up the swing to match the load's momentum
- Call for additional tagline workers while continuing the lift
Correct answer: Stop all motion and allow the load to dampen naturally before resuming
Stopping all crane movement allows pendulum energy to dissipate and brings the load back under control safely.
Question 7: What is the function of a load moment indicator (LMI) on a crane?
- It measures wind speed at the boom tip
- It continuously calculates the load on the hook and warns when approaching rated capacity (Correct answer)
- It records the number of lift cycles per hour
- It monitors engine torque during lifts
Correct answer: It continuously calculates the load on the hook and warns when approaching rated capacity
An LMI uses boom angle, length, and line pull data to compute the actual load moment and alert the operator before overloading occurs.
NCCER Crane Site Operations & Hazard Recognition 3
What is the main purpose of using outrigger pads (cribbing) under a crane's outrigger floats?