The following terms and definitions below are basic definitions pertaining to Nylon Slings, Polyester Slings and Web Slings. Please feel free to call us at 1-888-426-3755 or contact us via our website so our expert staff can help you obtain the proper safety and inspection information for your lifting slings.


The mechanical wearing of surface resulting from frictional contact with materials or objects.

Breaking Strength

That total force (lbs. or kg.) at which the sling fails. The total weight strain that can be applied before failure. In the USA, it is usually at five times the rated capacity; in Europe it is seven times rated capacity. Also known as Ultimate Load.

Competent Person

A person designated for inspection who is trained and qualified by knowledge and practical experience and who has the necessary instructions to enable the required test or examination to be carried out.

Design Factor

An industry term denoting theoretical reserve capability. Usually computed dividing the catalog stated ultimate load by the catalog stated working load limit and generally expressed as a ratio, for example 5 to 1 or 7 to 1.


The measurement of stretch, expressed as a percentage of the finished length.


A load bearing metal component that is fitted to the sling. Can be of steel, aluminum or other material that will sustain the rated capacity of the sling.


The distance between bearing points of the sling.

Proof Load

The average load to which an item may be subjected before visual deformation occurs, or a load that is applied in the performance of a proof test.

Proof Test

A term designating a tensile test applied to the item for the sole purpose of detecting injurious defects in the material or manufacture.

Rated Load Value/Rated Capacity

The maximum recommended load that should be exerted on the item. The following terms are also used for the term Rated Load: "Safe Working Load," "Working Load," "Working Load Limit," and the "Resultant Safe Working Load." All rated load values, unless noted otherwise, are for in-line pull with respect to the centerline of the item.

Shock Load

A resulting load from the rapid change of movement, such as impacting or jerking, of a static load. A Shock Load is generally significantly greater than the static load.

Synthetic Fiber

Man-made material used for the cover, the core and the thread of the Twin-Path sling products.


Extensions of the load core yarns. When the sling is stretched beyond its elastic limit, they shrink and eventually disappear under the tag. Take out of service if less than 1/2 inch is exposed.


The synthetic yarn that is used to sew the sling covers and tag and to provide the stitch that separates the individual load cores.


A patented and trademarked product, which is composed, of two separate load bearing cores and two separate seamless covers in a single sling. Hanes Supply's Buffalo Sling is a licensed manufacturer of Twin-Path® Slings.