Load chart
Also called Duty chart, Rated capacity chart
Manufacturer’s data, specific to an individual crane, showing the maximum load it can lift at a given radius and configuration, including how outrigger reactions vary with load and radius. The appointed person and crane supervisor use the load chart to confirm a lift is within the crane’s capacity and to calculate the ground loads that need to be spread by mats or pads.
In practice
A load chart is not one table but a set of them, one per configuration: outrigger extension, counterweight fitted, boom and jib arrangement, on outriggers or on wheels. Reading a figure from the wrong table is the classic error, and it is easy to make, because the tables look alike and the difference between them can be large.
Where this comes from: Manufacturer’s data for the specific machine. Nothing on this page substitutes for the chart supplied with the crane on site.
Where it matters on site
For ground bearing, the chart is where the reactions come from — so the configuration used to pick the mat and the configuration the crane is actually rigged in have to be the same one. A crane re-rigged on site to reach further is working to a different page of the chart, and the matting was sized from the old page.