Keeping Factories, equipment, and, of course, employees safe is the duty of a rigger. These people have the training to know the fundamental requirements of safe rigging practices. Every day they must calculate wire rope weight limits for lifting loads, plan rope sling configurations for the loads being lifted and inspect wire ropes and machinery for damage or corrosion,
Knowledge of Sling Operations
Riggers must know safety regulations for sling configurations to maintain stability throughout load-lifting operations. Riggers must know the rigging and the ins and outs of using wire rope clips, shackles, and eyebolts safely.
Never Use Damaged Equipment
Equipment that is determined to be damaged or unsafe must be removed from service immediately. Professionals must verify functionality if an operator is in doubt. All operations must be stopped as soon as any problems are discovered until the problem is professionally repaired or new equipment is purchased.
Determine Working Load Limit
To calculate the ropes necessary to lift the load, the rigger must factor in many different equations. They must know the exact limit of the weight they will be hoisting to figure out the ropes to create the rope sling used to lift the load. The shape and size of the load must be taken into account as well. These calculations will tell the rigger what kind of wire rope sling, what strength and construction of wire rope, and what specific rigging will hold the bundle during the lift. The competent person also must know the hoist machine and what size wire rope it requires for doing its job, and how much weight it can bear.
Wire Rope Constructions
Riggers must know how they will be using the wire rope to purchase the right cable. Wire rope is made for bending, but not for distortion. Riggers know that different wire rope constructions allow for stiffer rope or more flexible rope, depending on the amounts of wires used. More external cables afford more flexibility. Knowing these different abilities and characteristics are essential information for riggers in making the determination for which rope to use for which job.
Weight Limits of Hoisting Gear
When assessing the working load limit of hoisting gear, riggers must calculate the center of gravity, improper sling angles, point loading, and wear. Users must factor in the rating for both equipment and hardware. Each wire rope comes with its own specific Work Load Limit and maximum breaking strength. When calculating weight limits and regulations for hoisting gear, they must also consider that the Working Load Limits are based on pristine conditions and make corrections for them. Riggers must have the exact weight of the item to be lifted to purchase the correct rope size, construction, and rigging for the rope sling.
Companies who use wire rope indoors don’t usually need to plan for harsh weather conditions like some riggers do. When riggers have to plan for extreme weather like rain or snow, they need to know the corrosion factor, how quickly the rope will erode in the cold, or out at sea, in or near the saltwater. They must also consider the lubrication on the wire rope, when to lubricate and which lubrication is needed. Knowing which finish to use is essential as well when using them outside.
Knowing Types of Rigging Supplies
Different types of rigging supplies and wire ropes have different abilities and characteristics, so users must know the ins-and-outs of their exact equipment. The shape and size of the load they are lifting will determine the type of wire rope sling necessary. There are various types of wire rope slings, like a single-leg sling (the most common sling), bridle slings with two, three, or four legs, braided slings, and choker slings made of wire rope. To calculate the length of the wire rope bridle, you must measure the length of the sling leg to the end of the hook. There are nylon slings and chain slings as well.
In addition to knowing the different configurations of rope slings, they must know the angles at which the ropes will be used and how much weight each rope will hold at different angles. Cables, when used at different angles, can only bear a certain percentage of their weight limit.
A rigger must also be aware of the different single-leg cable slings and how each of them works for each job. Eye and eye, eye and hook, eye and thimble, thimble and thimble, and sliding choker, each work in different ways and must be chosen carefully for each situation.
Safety is in the Math
Knowing all of these parameters for working with wire ropes in different situations and weather is the professional riggers job. It is imperative to overestimate the working weight load and rope limits because the conditions in the field are never the same as when the ropes are tested in a controlled environment.
For keeping equipment and employees safe, a rigger must know all of these safety regulations and more. When calculating the ropes’ angles when using lifts, they must figure in the weight being lifted and compare it with the weight limit specified for the cable. Yes, it is a lot of math, but it is the only thing keeping people, equipment, and precious cargo loads safe. Even then, accidents happen, which makes it even more important to be precise and make accommodations specific to the situation.
For Your Wire Rope and Rigging Needs
Here at Silver State Wire Rope and Rigging, our knowledgeable staff can help you find the correct equipment for the job at hand. We will supply you with all your rigging needs and answer any questions you may have. Contact us today!