Below The Hook: Modular spreader beams27 October 2023
There is a growing trend for modular spreader beams, driven by a number of factors, writes Dan Mongan, senior sales engineer at The Caldwell Group.
As a result of increasing demand for more versatile, lighter weight, below-thehook systems, coupled with the constant pressure to work to shorter lead times, certain manufacturers have designed modular spreader beams.
Spreader beams incorporate top rigging and are designed for a compressive load, whereas lifting beams are designed for a bending moment. A lifting beam has a lower headroom because of the absence of top rigging, as required by a spreader beam. Many people therefore think of traditional spreader beams being used outside where headroom or vertical clearance isn’t an issue.
Modular spreader beams are available in two- and four-point systems; in other words, to create two or four pick-points. The Caldwell Group’s two-point range covers 12t to 600t capacity and 12ft to 78ft in length, for instance, while four-point frames cover 30t to 140t and 20x20ft to 52x52ft. Of course, the usual understanding of geometry and rigging forces apply to calculate what capacity is on offer at various spans and sizes.
What we call our Dura-Mod range includes drop links, corner fittings, end fittings, spreader sections and bolt kits. These components can be easily configured to meet a variety of applications. Where regular spreader beams might be used in one-over-two configuration to create four pick points, Dura-Mod users, for example, simply need to remove the end fittings and add corner sections – the struts are the same. All such spreaders utilise standard shackles that are available from all major manufacturers. The manufacturer specifies top sling lengths, while the load determines lower rigging.
A standout advantage is that an equipment hirer can stock various sizes of components and build a spreader beam to meet end-use requirements. We were involved in dialogue with a company recently that initially wanted a custom 16ftlong beam. Sure, we could’ve provided them with a beam of that length but, as we explained, if in two years, they want a longer (or shorter) beam, they’ll have to make a completely new purchase. With a modular concept, they can simply buy new sections and change the length. Further, their stock then becomes even wider and more flexible.
Think of the storage and transportation benefits too. In our case, the longest single Dura-Mod component is only 20ft. Companies can build up an inventory of drop links, corner fittings, end fittings, spreader sections, and bolt kits that can be easily stored and moved from one project to another. Moving and storing a large custom beam or frame can be awkward and expensive due to the space required beyond the actual spreader and its rigging components.
In fact, it doesn’t take a huge volume of components to be able to build any size of spreader beam. Without much effort, a distributor can go from a 3ft beam up to a 24ft beam by adding in sections in the case of the Dura-Mod line-up. Imagine the benefits to a rental house – when the phone rings and someone asks if they’ve got a beam in a certain length or capacity, the answer is nearly always ‘yes’. And many of the same components can be used in a completely different size, shape, and capacity of beam the following day, or lift.
Of course, whenever a rigging practice is made easier, cheaper and more accessible, it is always important to stress that safety must always be observed, which doesn’t change if it’s a hulking, fixed, custom beam, or a 12ft, 12t capacity solution. We provide documentation that outlines limits on how many sections can be used (maximum of five) due to tolerances. It’s not best practice to build a 20ft beam of 1ft sections. Fastening and torquing must also be given utmost care.
Due to the inherent nature of two- and four-point modular systems, manufacturers label components with their maximum capacity; the user is responsible for reviewing chart information to determine assembly capacity and adding appropriate assembly labels. All drop links, corner fittings, end fittings and spreader sections must come together to create a complete rigging system that meets best practice guidance and safety standards and is labelled accordingly. That’s an important point to emphasise because this makes modular equipment different to many other below-the-hook, material handling and lifting technologies on the market.
In a world that is striving to be more economically efficient and sustainable, expect modular spreader beams to become even more popular, driven by the many manufacturing, storage and usage benefits outlined above.