How to Read and Understand an Alloy Chain Sling Capacity

How to Read and Understand an Alloy Chain Sling Capacity

Contributed by Bob Kozickie, Technical Sales Support Manager

Lieying Group provides top-quality products to various industries worldwide with a commitment to excellence. Our goal is to offer our customers high value-added products, creating a better future together.

Alloy Chain Sling Capacity Charts are disseminated by Standards Associations, chain manufacturers, and nearly every rigging shop. These charts can be formatted as large wall posters or compact pocket guides for riggers. At first glance, these charts seem like straightforward guidelines for the maximum lifting capacity or Working Load Limit (WLL) of an alloy chain sling at specific lifting angles. When multiple chain slings are used to lift a load, a common question arises: can you just add the capacities on the ID Tag to get the slings' safe WLL? The ability to interpret an alloy chain sling capacity chart is an invaluable skill for any competent rigger.

Understanding Single Leg Chain Slings

The simplest column to understand is the Single Leg chain sling, as these are only rigged in a vertical hitch configuration and rated at a 90-degree angle to the load. The WLL is consistent with the corresponding alloy chain grade and attachments. However, the WLL changes when two single leg chain slings are used together in a single two-point lift.

Double Leg Chain Slings

The next column is the Double Leg chain slings, which involve two legs attached to a single master link or two single leg chain slings used together. This configuration is rated at a maximum sling angle of 60 degrees, forming an equilateral triangle. The capacity of multi-leg slings decreases as the distance between the lifting points increases.

Example with Grade 100 Alloy Chain

For example, a 1/2" Grade 100 alloy chain is rated at 15,000 lbs. If only two Single Leg chain slings are available, the Double Leg capacity column must be used. Doubling the capacity incorrectly could exceed the 60-degree angle rating of 26,000 lbs. by 4,000 lbs., posing a risk.

Triple and Quad Chain Slings

When using triple and quad chain slings, understanding the capacity chart is crucial. Both three and four leg alloy chain slings are rated the same. Chain's rigidity means that in a four-point lift, only three legs support the load at any time, with one leg acting as a balancing leg. Incorrectly doubling the capacity of a Double Leg configuration can lead to overloading and potential failure.

Importance of Lifting Angles

Proper understanding of lifting angles for multi-leg chain slings is critical for safe rigging. As the lifting angles decrease, the weight experienced by the sling increases. A chain sling leg at 60 degrees sees 1.15 times the load, at 45 degrees sees 1.41 times, and at 30 degrees sees 2.0 times the load on each leg. Angles should never go below 30 degrees, and special lifting devices may be required for such scenarios.

Alloy Chain Sling Capacity Charts are based on engineering calculations and extensive testing. Although they may seem straightforward, the complexities of rigging with chain slings demand proper training and understanding. For in-depth training on alloy chain slings, contact Peerless or a Peerless distributor.

Working Load Limits of Chain

Whether you're transporting machinery, using tow chains, or involved in logging, knowing the working load limits of the chains you use is crucial. Chains have a WLL, roughly one-third of their break strengths.

How to Find the Working Load Limit

The chain grade and diameter determine its WLL, which you can find embossed on the chain itself.

Interested in learning more about Load Lifting Chains Wholesale? Contact us for expert consultation!

Types of Chain

Grade 30 Chain

Grade 30, also known as Grade 30 Proof Coil Chain, is a multipurpose, economical chain used in various industries. It is not safe for overhead lifting.

Grade 43 Chain

Grade 43 High Test Chain, commonly used in towing and logging, is not suitable for overhead lifting.

Grade 70 Chain

Grade 70 Transport Chain, or "Grade 70 Truckers Chain," is used for securing loads but is unsafe for overhead lifting.

Grade 80 Chain

Grade 80 Alloy Chain is heat-treated and suitable for overhead lifting, often used as a heavy-duty tow chain.

Grade 100 Chain

Grade 100 chain offers a 25% higher WLL than Grade 80 and is safe for overhead lifting.

Grade 120 Chain

Grade 120 chain is 50% stronger than Grade 80 and 20% stronger than Grade 100, offering improved abrasion resistance and safety for overhead lifts.

For more information, please visit How to Use a Chain Hoist.

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