How do you Choose Between a Spreader Beam and a Lifting Beam?
What is the difference between a spreader beam and a lifting beam? And which one best suits your requirements below-the-hook?
These are common questions that we put to Tom Eicher, director of engineering at The Caldwell Group Inc., a manufacturer of a range of below-the-hook lifting solutions for crane, material handling and other applications, including lifting and spreader beams, vacuum attachments, remote releasing hooks, and gantry cranes.
Lifting beams are typically designed for a bending moment versus the spreader beam that incorporates top rigging and is designed for a compressive load.
There are applications when both bending and compressive forces are accounted for in the design of the lifting device but in the general application of a spreader beam versus a lifting beam, this statement will be true.
Caldwell, an FAD Equipment Store vendor, manufactures more lifting beams than spreader beams. Of those lifting beams, many are customized for specific lift points, whereas the split is about 50-50 for standard and custom spreader beams. Standard spreader beams are manufactured up to 130-ton capacity, and lifting beams 40-ton capacity. Caldwell's standard offering of lifting beams covers a span from 3 ft. to 42 ft. with capacities ranging from 500 lbs. to 80 ton, depending on span.
The two primary considerations when deciding whether a spreader beam or lifting beam is required are capacity and headroom.
A low headroom beam with multiple spreads providing flexible solutions to handle a wider range of load sizes.
This Caldwell adjustable spreader beam is ideal for outdoor applications and where headroom is not limited.
When selecting a lifting device for large loads, a rigger can gain additional capacity using a spreader beam versus a lifting beam due to the increased dead load of the lifting device while taking into account the rated capacity of the crane or hoist. With a spreader beam, the top rigging will support the majority of the load in its hardware, while the spreader beam is designed for the compressive load.
A lifting beam has a lower headroom because, as discussed, a spreader beam requires top rigging that increases the headroom required. This is why many people generally think of spreader beams being used outside where headroom or vertical clearance isn't an issue. It’s true that traditional lifting beams are commonly used indoors where users have headroom considerations and the load is balanced and stable.
The stability of a spreader beam is a result of taller headroom (due to top rigging) and a lower center of gravity from the crane hook attachment to the point of the assembly (lifter and load), whereas the lifting beam has a single lifting point.
A spreader beam has more stability than a single, centered lift bail on a lifting beam. To add stability to a lifting beam, a second bail can be used as long as there are two cranes to vertically hoist the lifting beam and load. Typically, twin bails require two cranes to lift. Twin bails shall not be used for angled top rigging (unless designed for this) due to the angles and forces that the lift beam will see (more below).
Spreader beams are often lighter weight for the loads versus a spreader beam, due to the design and top rigging.
Adjustable spreader beams
There are a handful of companies globally that make adjustable spreader beams.
Notably, Caldwell recently launched the Dura-Mod Modular Spreader Beam, a versatile, lightweight alternative to fixed and multiple point below-the-hook solutions up to 170-ton capacity. Each system will consist of a pair of end fittings and drop links, and two upper and lower shackles to make the shortest possible configuration. From there it is a simple case of combining intermediate spreader sections to achieve the required span. The single longest component is only 20 ft.
If a four-point or rectangular spreader frame is required for an application, you simply need to remove the end fittings and add corner sections—the struts are the same. All Dura-Mod spreaders utilize standard shackles that are available from all major manufacturers. Caldwell specifies top sling lengths, while the load determines lower rigging.
ASME B30.20 and ASME BTH-1 standards are recognized in the United States as the go-to industry standards. The design category established in the BTH-1 design criteria is based on category A (2:1 Yield 2.4:1 Ultimate), Category B (3:1 Yield 3.6 Ultimate), Category C (6:1 Yield 7.2:1 Ultimate).
The factor of safety and design of a lifter is based on the customer’s requirements such as:
- Number of lifts per day
- Severe environment
- Specific industry requirements, such as nuclear, military, or energy
These are only a few considerations to establish the category needed.
For reference, all Dura-Mod spreaders conform to ASME B30.20 and BTH-1 Design Category B, Class 0.
Much of the B30.20 guidance is interchangeable but when using a spreader beam, it’s important that the sling angles are rigged within the design criteria of the beam. Again, in simple terms, a 60-degree rigging angle puts less compression through the beam than a 45-degree rigging angle.
Another question we get a lot is: how much does a spreader beam or lifting beam cost? The answer, as in many scenarios involving material handling equipment, is: it depends. In most instances, the relative and comparative cost for us to manufacture a lifting beam is more than a spreader beam without rigging.