Glossary of Rigging

Basic Terms to Understand

Anchor Point: The location where a tie-down is attached to a vehicle or trailer. If the anchor point cannot support the force of the tie-down system, the load rating will be limited by the anchor point’s strength.

Breaking Strength Capacity: The minimum load a component or assembly can endure before failing. An assembly is only as strong as its weakest component.

Cargo: All materials carried by a vehicle or trailer, including those used for operating the vehicle.

Cotton: A lightweight, non-abrasive material ideal for moving blankets and furniture pads, often used in higher-quality products.

Cross-Docking: The process of moving goods directly from the receiving dock to the shipping dock to avoid storage costs.

Cubic Capacity: The carrying capacity of equipment measured in cubic feet.

Cyclic Test: A test to determine the cyclic life or acceptable cyclic rating of a tie-down component or assembly.

Design Factor: The ratio of the breaking strength to the working load limit assigned to each synthetic web tie-down assembly.

Direct Tie-Down: A tie-down intended to provide direct resistance to a potential shift of an item.

Elongation: The length of stretch a specific amount of pull creates, divided by the original length and multiplied by 100%.

Fabrication Efficiency: The break strength of a synthetic web tie-down assembly as a percentage of the webbing strength before fabrication.

Heavy Duty Truck: A truck with a gross vehicle weight generally exceeding 19,500 pounds (class 6-8). Minimum weights may vary by laws or government agencies.

Indirect Tie-Down: A tie-down whose tension increases the pressure on an article or stack of articles on the vehicle or trailer deck.

Keeper: A device on a hook to prevent it from accidentally releasing.

Length: The distance between the extreme end bearing points of the synthetic web tie-down assembly, including the fittings.

Load Binder: A binder with an over-center locking action.

Nylon: A soft yet strong material with good elongation and recovery properties, resistant to abrasion and mildew. It is ideal for heavy-duty recovery straps, although it loses strength when wet.

Polyester: A soft, low-stretch material that dries quickly and retains much of its strength when wet. It is ideal for outdoor ratchet tie-down assemblies, as it resists UV light, mildew, and abrasion.

Polypropylene: An economical, lightweight material that repels water and resists mildew, most acids, and alkalis.

Proof Load Test: A non-destructive load test of a web tie-down assembly to a multiple of its working load limit.

Rated Load Capacity: Ratings established and/or regulated by industry or legislative standards, which may vary across industries.

Recovery Straps: Made from nylon, recovery straps are used for pulling immobile vehicles. They stretch and recoil, making vehicle recovery safer than with chains or cables. They can be used as tow straps in some cases and are available in various sizes, with common widths ranging from 2″ to 4″.

Safety Factor: The ratio between the breaking strength and the safe working load. Generally, a safety factor of four is acceptable, but it can vary depending on the line’s condition and use circumstances. The safety factor should never be less than three and can be as high as eight or ten.

Selvage: The woven or knitted edge of synthetic webbing designed to prevent raveling.

Sew/Stitch Pattern: The pattern of stitches used to sew webbing together.

Shoring Bar: A structural section placed transversely between the walls of a vehicle to prevent cargo from tipping or shifting.

Stuffer: A longitudinal load-bearing yarn in webbing.

Tons: A unit of weight equal to different pounds depending on the measurement system. The US ton (short ton) equals 2,000 lbs., abbreviated as “T”. In the metric system, a ton (tonne) equals 2,204.6 lbs., abbreviated as “t”.

Tow Straps: Straps used for towing, which may have snap hooks or auto hooks on each end. They should not be used for recovery applications due to the risk of breaking and causing injury or death. Lighter than chains, they are easy to carry for towing purposes.

Ultimate (Destructive) Test: A straight tensile load test of the synthetic web tie-down assembly to failure. The failure load is the average breaking strength value of at least five test samples.

Winch: A device for tensioning webbing or wire rope tie-downs, fitted with a means to lock the initial tension.

Working Load Limit (WLL): The maximum load capacity any component or assembly should handle during use. It is recommended that the working load limit not exceed 1/3 of the breaking strength capacity. For example, a ratchet strap rated at 6,000 pounds would have a working load limit of 2,000 pounds.