What is the primary purpose of a crane load capacity chart?

• A. It reduces weather impact on lifting.
• B. It shows the maximum safe load for a given boom length and radius.
• C. It lists the maintenance interval for lifting gear.
• D. It indicates the expected duration of the lift.

Answer: (B)

The main idea is that a crane load capacity chart tells you the heaviest load you can lift for a specific crane configuration. The capacity depends on geometry: as the boom length gets longer or the load sits farther from the crane’s base (larger radius), leverage increases and the safe load decreases. The chart maps these safe capacities for different boom lengths and radii (and often different counterweight or outrigger setups), so you can verify that the planned lift is within what the crane can safely handle. If the load doesn’t fit the chart for the current configuration, you must adjust the setup—shorten the boom, reduce the radius, add counterweight, or use a different crane—before lifting. The other options relate to factors like weather, maintenance intervals, or lift duration, which are not what the capacity chart primarily provides.