After the hoist rope, sling is the most commonly used piece of rigging equipment. Observe the following precautions with slings.
• Never use damaged slings. Inspect slings regularly to ensure their safety. Check wire rope slings for kinking, wear, abrasion, broken wires, worn or cracked fittings, loose seizings and splices, crushing, flattening, and rust or corrosion. Pay special attention to the areas around thimbles and other fittings.
• Slings should be marked with an identification number and their maximum capacity on a flat ferrule or permanently attached ring. Mark the capacity of the sling for a vertical load or at an angle of 45°. Ensure that everyone is aware of how the rating system works.
• Avoid sharp bends, pinching, and crushing. Use loops and thimbles at all times. Corner pads that prevent the sling from being sharply bent or cut can be made from split sections of large-diameter pipe, corner saddles, padding, or blocking.
Ensure that Slings are Protected at All Sharp Corners on Heavy Items
• Never allow wire rope slings, or any wire rope, to lie on the ground for long periods of time or on damp or wet surfaces, rusty steel, or near corrosive substances.
• Avoid dragging slings out from underneath loads.
• Keep wire rope slings away from flame cutting and electric welding.
• Never make slings from discarded hoist rope.
• Avoid using single-leg wire rope slings with hand-spliced eyes. The load can spin, causing the rope to unlay and the splice to pull out. Use slings with Flemish Spliced Eyes.
• Never wrap a wire rope completely around a hook. The sharp radius will damage the sling.
• Avoid bending the eye section of wire rope slings around corners. The bend will weaken the splice or swaging. There must be no bending near any attached fitting.
• Ensure that the sling angle is always greater than 45°. When the horizontal distance between the attachment points on the load is less than the length of the shortest sling leg, then the angle is greater than 60° and generally safe.
• Multi-leg slings. Do not assume that a multi-leg bridle sling will safely lift a load equal to the safe load on one leg multiplied by the number of legs. There is no way of knowing that each leg is carrying its fair share of the load. With slings having more than two legs and a rigid load, it is possible for some of the legs to take practically the full load while the others merely balance it.
As a result, when lifting rigid objects with three- or four-leg bridle slings, make sure that at least two of the legs alone can support the total load. In other words, consider multi-leg slings used on a rigid load as having only two legs. Where the load is flexible and can adjust itself to the sling legs, assume that each leg can take its own share of the load.
When using multi-leg slings to lift loads in which one end is much heavier than the other, the tension on the most heavily loaded leg is much more important than the total weight. The sling must be selected to suit the most heavily loaded leg rather than the total weight.
• When using choker hitches, do not force the eye down towards the load once tension is applied. Rope damage is the invariable result.
• Whenever two or more rope eyes must be placed over a hook, install a shackle on the hook with the shackle pin resting in the hook and attach the rope eyes to the shackle. This will prevent the spread of the sling legs from opening up the hook and prevent the eyes from damaging each other under load.
Rigging, Lifting, and Landing Loads
• Rig loads to prevent any parts from shifting or dislodging during the lift. Suspended loads should be securely slung and properly balanced before they are set in motion.
• Keep the load under control at all times. Where personnel may be endangered by a rotating or swaying load, use one or more taglines to prevent uncontrolled motion.
• Loads must be safely landed and properly blocked before being unhooked and unslung.
• Lifting beams should be plainly marked with their weight and designed working loads and should only be used for their intended purpose.
• Never wrap the hoist rope around the load. Attach the load to the hook by slings or other rigging devices adequate and suitable to the load being lifted.
• The load line should be brought over the load’s centre of gravity before the lift is started.
• Keep hands away from pinch points as slack is being taken up.
• Wear gloves when handling wire rope.
• Make sure that everyone stands clear when loads are being lifted, lowered, and freed of slings. As slings are being withdrawn, their hooks may catch under the load and suddenly fly loose.
• Before making a lift, check to see that the sling is properly attached to the load.
• Never work under a suspended load.
• Never make temporary repairs to a sling. Procedures for proper repair should be established and followed.
• Secure the unused legs of a multi-leg sling before it is lifted.
• Never point-load a hook unless it is designed and rated for such use.
• Make sure that the load is free before lifting and that all sling legs are taking the load.
• When using two or more slings on a load, ensure that they are all made from the same material.
• Prepare adequate blocking before loads are lowered. Blocking can help prevent damage to slings.
• Operators: Avoid impact loading caused by sudden jerking during lifting and lowering. Take up slack on the sling gradually. Avoid lifting or swinging the load over workers below.
