Overhead lifting chain slings are useful tools for various types of overhead lifting operations and are frequently used for material handling in construction and manufacturing. Following industry guidelines is key to optimizing the use of these slings in a safe and effective manner.
Why is safety such an important issue for overhead lifting? Lifting or applying loads in any direction is incredibly dangerous work. Failure of any component or link in the chain can result in catastrophic failure. Heavy loads can be dropped, causing massive damage to equipment and facilities as well as serious injury or even death to workers. The operation, care, and maintenance of chain slings are important factors in the long-term, safe use of these devices and ensure the safety of anyone working with or near an overhead lifting device.
Chain sling or sling component use is governed by the U.S. Department of Labor OSHA regulations. In particular, Section 1910.184 governs the operation and usage of alloy steel chain slings and sling components. A chain sling or chain product must always be operated in strict accordance with federal OSHA regulations. Any user or operator of a chain sling device should be completely familiar with these OSHA requirements.
SELECTION OF CHAIN SLINGS
Chain slings come in a variety of lengths and combinations of hooks and components, depending on the lifting application. The chain manufacturers have specified a variety of chain testing and safety standards in American Society of Mechanical Engineers (ASME) B30.9, ASTM-A906, and the National Association of Chain Manufacturers. Any chain sling used for lifting must have suitable characteristics for the type of load hitch and environment used and must be in accordance with ASME B30.9, Sections 9-1.5 and 9-1.8.
The working load limit (WLL), or rated capacity of chains and slings, is determined by the “grade” of the chain and its components. For overhead lifting, only high-grade alloy steel chains and components may be used. These devices must meet a variety of strict quality standards such as minimum breaking strength, fatigue testing, and heat resistance.
The most commonly used chains for overhead lifting are rated at Grade 80, however, the industry is moving to the safer and stronger Grade 100 and Grade 120 chains. The WLL and lifting capacity increases as the grade increases. For example, a 3/8 inch Grade 80 chain has a WLLof 7100 pounds, a 3/8 inch Grade 100 chain has a WLL of 8800 pounds, and a 3/8 inch Grade 120 chain has a WLLof 10,600 pounds—50% higher than Grade 80. For safety reasons, each chain and sling is rated with a 4:1 design factor. The 3/8 inch Grade 80 chain with a WLLof 7100 pounds is pull tested to 14,200 pounds and has a minimum breaking load of 28,400 pounds.
Every chain or chain sling is only as strong as its weakest link, so it is very important that every component of the sling meets WLL. All chains and components must be marked by the manufacturer with a grade from which the load rating can be determined. It is important to note that a number of factors such as lifting at an angle, wrapping the chain around a load, or extreme temperature reduce the WLL of the sling substantially. These factors must be considered when determining what type of sling is necessary to lift a load.
READ THE LABEL
Each chain sling is supplied with a certificate and an identification tag. The identification tag includes the name of the manufacturer, the grade of chain, the nominal chain size, the number of chain legs, the length (reach) of the sling, the rated loads for the sling assembly, and the angle upon which the rating is based. Always look for proper and clear identification, especially the WLL. Some manufacturers also provide sling warning kits that can be attached to a chain sling. The owner and user of the chain sling are responsible for maintaining and repairing the sling and its identification tags.
Keep in mind these usage and training safety rules:
Only trained individuals are allowed to use chains slings as specified by OSHA 1926.20 (a)(4)
- Operate a chain sling in strict accordance with OSHA 1910.184 and ASME B30.9
- No portion of the body shall be placed between the sling and the load or the sling and the crane or hoisting hook
- In no circumstance shall personnel stand or pass under a suspended load
- Slings may be shortened or lengthened only by methods approved by the manufacturer or a qualified person
- Sharp edges in contact with the sling should be padded to protect the sling
- Slings shall not be constricted, bunched, or pinched by the load, hook, or any fitting.