Capacity of Cranes and it's Importance

There are numerous capacities and specifications of Cranes used in construction industry. Therefore the relevant selection is important.

9/12/20232 min read

The capacity of a crane refers to its maximum load-bearing capability, and it varies depending on the type and configuration of the crane. Crane capacity is typically expressed in terms of two main parameters: lifting capacity and radius.

1. Lifting Capacity: This represents the maximum weight a crane can lift under ideal conditions. It's usually specified in pounds (lbs) or kilograms (kg). Crane manufacturers provide load charts or capacity tables that detail the crane's lifting capacity for different configurations, including boom length, boom angle, and counterweight setup. The lifting capacity decreases as the boom extends or the angle changes.

2. Radius (or Reach): The radius refers to the horizontal distance between the crane's center of rotation (slewing axis) and the load being lifted. A crane's lifting capacity is directly affected by the radius. As the radius increases, the lifting capacity decreases. Load charts typically provide a range of radii to help operators determine the crane's capacity at specific distances from the crane's center.

It's essential to note that crane capacity is influenced by various factors, including:

- Crane Type: Different types of cranes (e.g., mobile cranes, tower cranes, crawler cranes) have varying lifting capacities based on their design and purpose.

- Boom Length: Extending or retracting the crane's boom affects its capacity. A shorter boom can handle heavier loads at closer radii, while a longer boom may be needed for more extended reaches.

- Boom Angle: The angle of the boom (raised or lowered) also impacts lifting capacity. The load chart provides capacity values for different boom angles.

- Counterweight: Some cranes can adjust their lifting capacity by adding or removing counterweights. Proper counterweighting is crucial for maintaining stability and capacity.

- Outriggers/Stabilizers: Mobile cranes often have outriggers or stabilizers that provide additional support and can influence the crane's capacity on uneven ground.

- Environmental Conditions: Factors like wind speed, temperature, and elevation can affect a crane's capacity. Manufacturers provide correction factors in load charts for such conditions.

- Rigging and Load Configuration: The type of rigging equipment used and how the load is configured (single line, double line, multiple part lines, etc.) can affect the crane's effective capacity.

It's vital for crane operators and personnel involved in lifting operations to consult the crane's load chart and consider these factors to ensure safe and efficient crane use. Additionally, local regulations and safety standards should always be followed when determining and operating within a crane's capacity limits to prevent accidents and ensure safety on the job site.