RH: Inspection Of Material Hoisitng Slings

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Chapter:- Rigging & Hoisting

Inspection Of Material Hoisitng Slings

Slings

Sling: An assembly which connects the load to the material handling (lifting) equipment.

Types of Slings:

1. Chain Sling
2. Wire Rope Sling
3. Synthetic Web Sling

Frequency of Sling Inspections

• All slings are to be inspected each day prior to their use.
• This includes chain, wire rope and synthetic slings and their attachments, i.e. master links, clips, hooks etc.
• At least once in every 12 months depends on the state requirement, third party inspection & certification to be carried out.

 Sling Load Capacity and Sling Angles

1. The load capacity of the sling is determined by its weakest component.
2. Never overload a sling.
3. Remember, wider the sling legs are spread apart, less the sling can lift !!!.

 Chain Sling Inspection

1. Cracks, stretches, severe nicks, gouges, welding splattered or deformed master links, coupling links, chains or other components.
2. One leg of a double or triple chain sling is longer than the others.
3. Hooks have been opened more than 25% of the normal throat opening measured at the narrowest point or twisted more than 10 degrees from the plane of the unbent hook.

Special Precautions

• Chain slings should never be modified or repaired by operators / unauthorized workers.
• It is important to realize that the capacity of a sling decreases as the angle at which it is used to lift increases.

Wire Rope Sling Inspection

1. Check for three randomly distributed broken wires in one strand / in one rope lay.
2. Wear or scraping of 1/3 the original diameter of individual outside wires.
3. Kinking, crushing or any damage resulting in distortion of the wire rope.
4. End attachment / fittings are cracked, worn or deformed.
5. Corrosion of the rope.

Synthetic Web Sling Inspection

1. Acid or caustic burns on the sling.
2. Snags, punctures, tears or cuts.
3. Melting or charring of any part of the sling’s surface.
4. Stitching is broken or worn.
5. Sling is in stretched / damaged condition. [To assist operators in determining if a sling is stretched, manufacturers incorporate a red wear cord / Red core yarn inside of the sling]

When this red wear cord can be readily seen upon inspecting, the sling has been stretched and to be removed from service.

Do’s :  

• Hang / place the slings on racks, keep it in a clean & dry environment.
• Always hook with a “closed hook” arrangement & lift loads straight up.
• Keep loads balanced to prevent overloading the slings.
• Make sure the hook is always over the center of gravity of the load before lifting it.
• Protect the chain surface from contact with sharp corners, which can cause permanent damage through gouging or abnormal stress and wear.
• Inspect the slings before every use.

Don’ts :

• Storage of slings on the bare floor & dragging of slings across the floor.
• Never provide shock to load slings & rest a load on a sling or pinch a sling between the load and the floor.
• A sling should not be pulled from under a load when the load is resting on the sling.
• Never apply a load to a twisted, knotted or kinked chain.
• Never force or hammer hooks or chains into position.
• Hands and Fingers shall not be placed between the sling and the load while the sling is being tightened around the load.
• The dirt and grit of the chains can cause excessive wear at the link bearing points.
• Never shorten a sling with knots, bolts or other makeshift devices.