Crane operation and safety
The Crane operation and safety domain tests whether you can turn a load chart into a safe lift and control the hazards around a working crane. Expect questions on capacity, stability, exclusion zones, power-line clearances, and shutdown criteria.
Capacity and stability
Rated capacity is the lesser of structural strength and tipping load for a specific configuration: boom length, radius, counterweight, outrigger spread, quadrant, and boom/jib combination. Deduct the hook block, slings, spreader bar, and any stowed jib or auxiliary head before comparing the load. Keep the crane level, outriggers fully extended on mats, and never shock-load or side-load the boom.
People and exclusion
No riders. Barricade the swing radius and the load path. Use tag lines from outside the crush zone. Stop when wind, visibility, ground conditions, or signals deteriorate.
Worked example
A 50-ton mobile crane is set with outriggers fully extended. At 35 ft radius with 80 ft main boom, the chart gives 12,000 lb. Rigging weighs 800 lb, so net capacity is 11,200 lb. The load is 10,500 lb - acceptable. If the same lift must reach 40 ft, the chart drops to 10,000 lb; net is 9,200 lb, so the 10,500 lb load is over capacity. The fix is a shorter radius, larger crane, or lighter load - not slower lifting.
Traps
Reading gross chart capacity as allowable load; using a chart for a different outrigger configuration; ignoring stowed jib weight; assuming a level-looking site is level; treating wind as irrelevant for a heavy load.