What is the purpose of a crane's load chart and how is it used during rigging?

• A. Weather History
• B. Maintenance Schedule
• C. Operator Hours
• D. Safe Lifting Capacities At Various Radii And Configurations

Answer: (D)

A crane's load chart communicates the safe lifting capacities at different radii and configurations and is used to verify that a planned lift stays within what the crane can safely handle. The chart shows the maximum load the crane can lift for various combinations of boom length, boom angle, and attachments like a jib or additional rigging. This gives you a clear limit to compare against the actual load you plan to move, so you don’t overload the crane or push it toward instability.

Before a lift, you confirm the crane is set up exactly as the chart assumes: outriggers or mats properly deployed on solid ground, ballast correct for the configuration, and the boom and any attachments configured to the same setup used to generate the chart. You determine the load’s weight and its center of gravity, estimate the radius—the distance from the crane’s center to the load—and then check the chart to see if that load is within the allowable capacity for that radius and configuration. If it isn’t, you must reduce the load, move the load closer to the crane (decrease the radius), or change the configuration to a higher-capacity setup. The chart also helps you plan the rigging path, select appropriate rigging hardware, and anticipate any derating if dynamic factors come into play, so the lift is executed within safe limits.

This tool isn’t about weather history, maintenance schedules, or operator hours. It’s specifically about ensuring the lift is within the crane’s rated capacities at the given reach and configuration, supporting safe planning and execution.