Crane Operations and Rigging Awareness
What the exam tests
Crane Operations and Rigging Awareness tests the signal person's ability to recognize how crane capacity, radius, load control, and rigging affect the lift. You are not expected to design the lift, but you must notice conditions that change the lift plan and stop the operation when they do.
Core rules
- Load chart capacity depends on radius, boom length, boom angle, counterweight, and outrigger configuration. As radius increases, capacity generally decreases. Booming down or swinging out can increase radius; booming up can decrease it.
- Watch the load moment indicator or rated capacity limiter and the anti-two-block device. An alarm is not a suggestion; stop and get the lift plan checked.
- Rigging affects capacity. Sling tension rises as the sling angle from horizontal decreases. A choker hitch reduces sling capacity compared with a vertical hitch. Know the load's center of gravity and use taglines to control rotation.
- Inspect slings, shackles, hooks, and rigging before use. Remove damaged gear from service.
- Keep personnel clear of the suspended load, swing radius, and pinch points. Never ride the load or stand under it. Use taglines rather than hands to control a load.
- Know the power-line approach distances and stop if the crane or load is approaching them.
Worked example
A pipe is being hoisted without a tagline. As it leaves the ground, it begins to rotate toward workers outside the barricade. The signal person gives STOP, has the load lowered, and requires a tagline before hoisting resumes. The reasoning is load control: the hazard is not crane capacity but uncontrolled rotation and struck-by exposure. The lift does not continue until the load is controlled.
Traps
Assuming capacity stays the same at every radius; ignoring an LMI or anti-two-block warning; using a choker hitch without allowing for reduced capacity; signaling a load through a barricade; directing a boom-down motion that puts the load outside the lift plan; standing inside the swing radius while signaling.