NCCCO Load Charts & Capacity Calculations 5

Question 1

What does 'tipping capacity' mean in the context of crane load charts?

Accepted Answer

The maximum load before the crane tips over

Answer

Tipping capacity is the theoretical load at which the crane would begin to tip; rated capacities are a percentage of this value.

Question 2

A crawler crane's load chart has separate columns for 'on crawlers' and 'with carbody blocked.' When would you use the blocked carbody column?

Accepted Answer

When the crane's carbody is supported by cribbing or blocking to increase stability

Answer

Blocking the carbody with cribbing distributes the load to a wider area, increasing stability and allowing higher rated capacities.

Question 3

How does wind affect crane load chart capacities during a lift?

Accepted Answer

Wind creates additional side loading that reduces effective lifting capacity

Answer

Wind applies lateral forces to the load, boom, and crane, creating additional stresses not reflected in standard load chart capacities.

Question 4

On a lattice boom crane load chart, why are capacities listed for specific boom lengths rather than a continuous range?

Accepted Answer

Lattice booms can only be assembled in fixed length increments

Answer

Lattice boom sections come in fixed lengths and can only be assembled in specific increments, so load charts reflect those discrete configurations.

Question 5

A load chart shows a maximum radius of 60 ft for a given configuration. The planned lift requires a 65 ft radius. What must the operator do?

Accepted Answer

The lift cannot be performed at that radius in that configuration

Answer

Operating beyond the maximum radius listed on the load chart is prohibited; the operator must reconfigure the crane or change the lift plan.

NCCCO (National Commission for the Certification of Crane Operators) Practice Test