Failure to follow warnings and instructions may result in serious injury or death.
Working Load Limit
This is the term used throughout the catalog. There are, however, other terms used in the industry that are interchangeable with the term Working Load Limit. These are: WLL, SWL, Safe Working Load, Rated Load Value, Resulting Safe Working Load, and Rated Capacity. Never exceed the Working Load Limit.
The Working Load Limit is the maximum load which should ever be applied to a product, even when the product is new and when the load is uniformly applied – straight line pull only. Avoid side loading. All catalog ratings are based upon usual environmental conditions, and consideration must be given to unusual conditions such as extreme high or low temperatures, chemical solutions or vapors, prolonged immersion in salt water, etc. Such conditions or high-risk applications may necessitate reducing the Working Load Limit.
Working Load Limit will not apply if product has been welded or otherwise modified.
Matching of Components
Components must match. Make certain that components such as hooks, links or shackles, etc. used with wire rope (or chain or cordage) are of suitable material size and strength to provide adequate safety protection. Attachments must be properly installed and must have a Working Load Limit at least equal to the product with which they are used. Remember: Any chain is only as strong as its weakest link.
Take notice of the recommendation from the Safety Council Accident Prevention Manual concerning all lifting operations:
“All employees working at cranes or hoists or assisting in hooking or arranging a load should be instructed to keep out from under the load. From a safety standpoint, one factor is paramount:
Conduct all lifting operations in such a manner, that if there were an equipment failure, no personnel would be injured. This means keep out from under a raised load and keep out of the line of force of any load.”
Do not operate a load over people. Do not ride on loads.
Keep out from under a raised load.
A load resulting from rapid change of movement, such as impacting, jerking, or swinging of a static load. Sudden release of tension is another form of shock loading.
Shock loads are generally significantly greater than static loads. Any shock loading must be considered when selecting the item for use in a system.
Avoid impacting, jerking, or swinging of load as the Working Load Limit could be exceeded and the Working Load Limit will not apply. A shock load is generally significantly greater than the static load. Avoid shock loads.
Avoid shock loads as they may exceed the Working Load Limit.
Inspect products regularly for visible damage, cracks, wear, elongation, rust, etc. Protect all products from corrosion. The need for periodic inspections cannot be overemphasized. No product can keep operating at its rated capacity indefinitely. Periodic inspections help determine when to replace a product and reduce rigging hazards. Keep inspection records to help pinpoint problems and to ensure periodic inspection intervals.
Due to the diversity of the products involved and uses to which they can be put, it would be counterproductive to make blanket recommendations for inspection procedures and frequency. Best results will be achieved when qualified personnel base their decisions on information from rigging and engineering manuals and on experience from actual use in the field. Refer to sources listed in
T.O.C. > ADDITIONAL REFERENCE MATERIAL > TECHNICAL SAFETY AND INFORMATION SOURCES for technical literature.
Frequency of inspection will depend on environmental conditions, application, storage of product prior to use, frequency of use, etc. When in doubt, inspect products prior to each use. Carefully check each item for wear, deformation, cracks, or elongation a sure sign of imminent failure. Immediately withdraw such items from service.
Rust damage is another potential hazard. When in doubt about the extent of corrosion or other damage, withdraw the items from service.
Destroy, rather than discard, items that have been judged defective. They might be used again by someone not aware of the hazard involved.
Additional warnings and information on wire rope, chain, cordage, blocks, and tools can be found in the Table of Contents by clicking on the warning symbol icon (). These should be read and understood thoroughly before using a particular item.
Information contained in this catalog is subject to change; all weights and dimensions are approximate. Ratings are stated in short tons (2,000lbs.) or pounds. All dimensions are in inches; all weights are in pounds, unless stated otherwise.
Working Load Limit (WLL)
The Working Load Limit is the maximum load which should ever be applied to the product, even when the product is new and when the load is uniformly applied – straight line pull only. Avoid side loading. All catalog ratings are based upon usual environmental conditions and consideration must be given to unusual conditions such as extreme high or low temperatures, chemical solutions or vapors, prolonged immersion in salt water, etc. Never exceed the Working Load Limit.
Proof Test Load (Proof Load)
The term “Proof Test” designates a quality control test applied to the product for the sole purpose of detecting defects in material or manufacture. The Proof Test Load (usually twice the Working Load Limit) is the load which the product withstood without deformation when new and under laboratory test conditions. A constantly increasing force is applied in direct line to the product at a uniform
rate of speed on a standard pull testing machine. The Proof Test Load does not mean the Working Load Limit should ever be exceeded.
Breaking Strength/Ultimate Strength
Do not use breaking strength as a criterion for service or design purposes. Refer to the Working Load Limit instead.
Breaking Strength is the average force at which the product, in the condition it would leave the factory, has been found by representative testing to break, when a constantly increasing force is applied in direct line to the product at a uniform rate of speed on a standard pull testing machine. Proof testing to twice the Working Load Limit does not apply to hand-spliced slings.
Remember: Breaking Strengths, when published, were obtained under controlled laboratory conditions. Listing of the Breaking Strength does not mean the Working Load Limit should ever be exceeded.
Design Factor (sometimes referred to as safety factor)
An industry term usually computed by dividing the catalog Breaking Strength by the catalog Working Load Limit and generally expressed as a ratio. For example: 5 to 1.