Configuring Rigging Products Correctly Minimizes Risk and Lowers Costs
Correctly configuring rigging equipment is essential to safe and efficient lifting operations. While weight calculations may seem straightforward, additional forces acting on the load must be accounted for to prevent overloading equipment and causing failures.
“There are well-known equations for determining the weight of a pick in crane operations,” said Zach Hayes, global product manager of sling chain and fittings at Kito Crosby. “However, the static weight of the item being lifted is only part of the equation. Other forces, such as angular loads and horizontal forces, also impact rigging performance.”
To illustrate, Hayes offers a simple analogy: imagine carrying two five-gallon buckets of water. When held close to your body, they each feel as heavy as their actual weight. However, if you extend your arms outward, the strain increases because of added horizontal forces.
In rigging, this effect is significant. In a multi-point pick with two legs of chain, the horizontal force can dramatically alter the actual load on each sling. At a 90-degree angle, the force remains equal to the load weight. At 60 degrees, the force increases by approximately 15%, and at 30 degrees, a sling leg could experience twice the vertical share of the load.
Accounting for these forces is crucial when choosing rigging products. One common point of failure, for example, are eye bolts, which are particularly vulnerable to angular loads.
“An eye bolt rated for a vertical lift may lose up to 70% of its capacity when used at a 45-degree angle,” Hayes explained. “This can introduce a dangerous point of failure. In fact, eye bolts are one of the most frequent causes of lifting failures.”
Selecting the right rigging equipment can mitigate these risks. “In non-repetitive lifting environments, chain is the most versatile option,” Hayes noted. “When paired with an adjustable sling, angles improve and even lifting of asymmetrical loads, such as L-shaped objects is ensured.”
Engineered Solutions
Kito Crosby offers a range of lifting and rigging products, including the Gunnebo Industries GrabiQ chain sling system. Designed for coupling, shortening and lifting, GrabiQ allows for precise control of asymmetrical loads by using one adjustable sling instead of separate long and short slings. The system also enables shortening chain lengths for low headroom applications and includes options for lifting bars, tubes and pipes.
Another key innovation is the midgrab chain shortener (MIG), which allows chain shortening at the hook rather than the master link. This is especially useful for long chain legs, as adjustments can be made closer to the load instead of the top of the sling. When not in use, the MIG can remain idle on the chain leg or be removed entirely, preventing inadvertent chain disengagement.
A case study highlights the impact of efficient rigging on operational costs. In a bridge construction project, the MIG was used for repetitive lifting of a 30,000-pound load. The setup included a 25-foot sling connected by chain with shackles to four attachment points at each corner of the load. The MIG was compared to a multi-sheave block, which had a maximum line speed of 20 feet per minute.
The analysis considered 15 lifts per day, with three sling adjustments of two minutes each per lift. The cost of crane rental and labor — including an operator and three riggers — totaled approximately $493 per hour. The use of the MIG resulted in a time savings of one hour and 40 minutes per day, translating to a cost reduction of approximately $824 per day.
“This example underscores the importance of proper rigging selection,” Hayes said. “Choosing the right tools can lead to substantial time and cost savings while enhancing safety.”
Minimizing Risk
Beyond equipment selection, training is critical in minimizing risk. Rigging professionals must understand how different forces impact lifting operations and how to apply best practices in real-world scenarios.
“Proper training is the foundation of safe and efficient lifting,” Hayes emphasized. “Industry organizations offer courses to ensure rigging professionals are well-equipped to handle various challenges. Kito Crosby is proud to support education initiatives, including its partnership with the International Union of Operating Engineers in Crosby, Texas.”
Ultimately, selecting the right rigging equipment and investing in training ensures that crane operations minimize risk while maximizing efficiency and cost savings.
