A crane’s load chart is the most important resource a crane operator should understand in order to plan the lift and ensure that loads are positioned where the equipment can safely lift the load and move it to where it needs to be placed.
For example, if a truckload of pipe is positioned too far away from the crane or equipment, it may not be safe to lift the pipe off the truck and place it next to or in the trench.
There are different crane manufacturers out there, like Terex, Liebherr, Grove, zoomlion, tadano… Only load charts that are found in the equipment operation manual or posted by the manufacturer in the equipment should be used. The load charts are specific to the make, model and configuration of a specific piece of equipment.
Dimensions
This section shows the dimensions of the crane, this type of information would be necessary for transportation purposes and for setting the crane up in tight areas.
Grosse Capacity/ Net Capacity
The values given in the load charts are “Gross Capacities”. The actual load the crane can lift is referred to as the “Net Capacity”. The maximum load must never exceed the crane’s Net Capacity!
The Gross Capacity must include the weight of anything and everything that is mounted or stowed on the boom of the crane or hanging from the boom tip. These are called “Capacity Deductions”.
Capacity Deductions: depend of the manufacturer of the crane. Make sure to understand what the manufacturer determines are capacity deductions. For exemple:
- Weight of the main load block
- Weight of the Headache ball or overhaul ball
- Effective weight of Jib (Stowed or erected and not used)
- Weight of all hanging cable
- Weight of all rigging
- Weight of Load
Crane Load Charts explanation
- This chart illustrates the gross or rated capacities of a crane.
- The numbers on top row represent boom lengths of the crane.
- The numbers in the left column represent operating radius.
- The numbers in the right column represent the the loaded boom angle.
- The gross capacity of this crane can be determined by either following the radius column and interesting boom length, or following the boom angle column and intersecting the radius or boom length column.
Range Diagram
A range diagram is usually included in every chart which illustrates how much boom length is needed to pick up and lift a load both at a distance and at height.
he range diagram is also helpful when setting up near structures. When deductions for the wire rope are required, a good place in the load chart to assist in making calculations for this would be the working range diagram.
The working range diagram to the right is separated into:
- Load radius (vertical lines)
- Boom tip height (horizontal lines)
- Boom jib length (arched sections)
- Boom angles (angled lines)
- Caution area (prohibited area)
