Where and How Do You Use a Spreader Bar?

  • Max sling angle is 90 degrees
  • Work in compression
  • higher capacity approximately 5:1

When protecting the load from angular forces is your top priority. The setup involves a two-leg top sling (made of wire rope or chain) that forms an A-frame shape from the crane hook down to the ends of the bar. Then, separate slings connect from the bottom of the bar vertically down to the load’s pick points.

The angle of that top sling is a key part of the equation. A very shallow angle creates massive amounts of compression in the bar, so riggers typically aim for a top sling angle between 45 and 60 degrees to keep the forces manageable.

Advantages and Disadvantages of Spreader Bars

Advantages

  • Load Protection: Its primary benefit is protecting the load from destructive inward-pulling forces.
  • Material Efficiency: Because it’s mainly in compression, it can be built lighter and is often less expensive than a lifting beam of the same capacity.
  • Works for Wide Spans: It is the superior choice for lifting very wide or long loads where a lifting beam would be impractically heavy.
  • Stability: The tall top rigging assembly lowers the overall center of gravity of the lift, which can add stability and reduce the chances of the load tipping.

Disadvantages

  • Headroom Demands: The A-frame top rigging requires a great deal of vertical space, making it unsuitable for indoor or low-clearance lifts.
  • Potential for Spinning: Long spreader bars lifting uneven loads may tend to rotate, often calling for the use of tag lines to control the load.
  • Limited Support Points: A standard spreader bar is a two-point lifting device and cannot support a load at points along its center.