Wire Rope Slings
- West-Grip wire rope slings (a Western Sling Company Brand) are fabricated from extra improved plow steel (EIPS) which is a tough, durable steel, combining great strength with high resistance to fatigue.
- All West-Grip wire rope slings have an independent wire rope core (IWRC) which has a superior resistance to crushing and distortion.
- Eyes are formed using a flemish eye splice and swaged sleeve.
- Tagged per A.S.M.E. B30.9 specifications.
- All sling assemblies with master links will have thimble eyes on the master links.
Operating Practices for Wire Rope Slings
- Can fail if damaged, misused, or overloaded.
- Inspect before use.
- Use only if trained.
- Observe rated load.
- Avoid sharp edges.
- Death or injury can occur from improper use or care.
Wire Rope Slings Instructions for Care, Use, Inspection and Repair
- Store in a clean, dry place and protect from mechanical damage, extreme heat, corrosion, or kinking.
- Maintain lubricated condition.
- Check weight of load.
- Check sling rated load for type of lift, angle of loading (see Load Angle Chart).
- Sling shall always be protected from being cut by sharp corners, sharp edges, protrusions, or abrasive surfaces.
- Center load on base (bowl) of hook unless hook is designed for point loading.
- Balance load.
- Avoid jerking load.
- Maintain load control.
- Be alert for snagging of load.
- Avoid dragging sling over rough surfaces and from under the load.
- Always stand clear of the load.
- No person allowed beneath the load.
- Persons are not to ride on sling or load.
- Avoid knotting, twisting, and kinking the sling.
- Restrict use to temperatures below 400°f (Fiber Core Wire Rope 180°F) and above -60°F.
- A single leg sling with hand tucked splice can unlay and drop the load if allowed to rotate during a lift.
- Always use a tag line.
- Before use, look for rope distortion, kinks, cut or broken strands, corrosion, heat damage, birdcaging, or crushing.
- Look at the end attachments f or cracks, wear or deformation, hooks with twists or a throat opening increase.
- Look for broken wires: for strand laid and single part slings, no more than 10 broken wires in 1 lay or 5 in 1 strand in 1 lay.
- For cable laid and braided broken wire inspection criteria, consult the manufacturer.
- If this wear or damage is present, if rated load tag is missing or illegible, remove from service and replace sling.
- If an inspection reveals that such wear or damage is present, replace the sling.
- Frequent inspection is done by the person handling the sling before each use and must include all of the before use items.
- Periodic inpsections are required at least annually for normal service quarterly or more frequently if in severe service or nearly constant use
- Periodic inspections are preformed by a designated person who records the observed condition and determines when further use would be hazardous.
- Any hazardous condition disclosed by an inspection shall require replacement of the wire rope.
- Repair is not an option.
Sling Load Angle
- Angle factor must be applied to calculate the reduced sling capacity when lifting force is not at 90° to the plane of the load.
- Multiply angle factor x sling’s vertical rated load to calculate the reduced capacity at that angle.
- Because of the greatly reduced lifting capacity, use extra care when the sling to load angle, also known as the horizontal angle, is less than 45° and do not make lifts of less than 30°load angle.
- Example: a sling with adequate capacity could be broken because of increased tension resulting from angles of less than 30°. When possible, use longer slings to minimize angular tension by increasing the angle.
|Sling Load Angle Chart|
Sling Choke Angle Effect
|Sling Choke Angle Effect Chart|
|Angle of Choke||Rated Capacity*|
|*Percent of Sling Rated Capacity in a Choker Hitch|
D:d Ratio for Slings
- Rated capacity of sling shall be decreased when D:d ratio will be smaller than that cited in the latest revision of ASME B30.9 Ch2.
- Consult the sling manufacturer for specific data or refer to the WRTB Wire Rope Sling User’s Manual.
- General Note: when D is 25 times the component rope diameter (d) the D:d is expressed as 25:1.
Wire Rope Sling Definitions
- AMERICAN NATIONAL STANDARD INSTITUTE (A.N.S.I.)
- AMERICAN SOCIETY OF MECHANICAL ENGINEERS (A.S.M.E.)
- An organization of scientists, engineers and other professionals whose primary function is the development and writing of standards for implementation on a national level.
- These standards would apply to wire rope slings, web slings, round slings, chain slings, blocks and hardware incorporated within this publication and/or site. ASME B30.9, B30.10 and B30.26 standards apply.
- OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION (O.S.H.A.)
- A federal regulatory organization with broad national indictment and enforcement powers.
- One of O.S.H.A.’s primary functions is the enforcement and regulations of those standards written by A.S.M.E., and adopted by O.S.H.A.
- Their enforcement powers would apply to the use of all items found within this publication and/or site.
- CFR Titles 29 Part 1926, dated 2011.
- MINIMUM BREAK STRENGTH
- The average load or force at which the product fails.
- NOT A LOAD RATING WORKING LOAD LIMIT (W.L.L.).
- The maximum load or force which should ever be applied to the product.
- The long standing federal standards on slings, regulated by O.S.H.A., uses a typical design factor of 5 to 1; that is a resultant working load limit of 20%, of the assembly minimum break strength. (May vary on some products).
- For example
- Alloy Chain uses a 4:1 factor.
- The newly written C.V.S.A. standards on tiedowns enforced by the D.O.T. use a typical design factor of 3:1; that is a resultant working load limit of 33% of the assembly minimum break strength.