Design Factors: W.L.L. & U.L.

WORKING LOAD LIMIT (W.L.L.)

The maximum mass or force which the product is authorized to support in general service when the pull is applied in-line; unless noted otherwise, with respect to the centerline of the product.

ULTIMATE LOAD (U.L.)

The average load or force at which the product fails or no longer supports the load.

DESIGN FACTOR

An industry term denoting a product’s theoretical reserve capability; usually computed by dividing the catalog ultimate load by the Working Load Limit. Generally expressed as a ratio; e.g.. 4 to 1 or 5 to 1 –4:1 or 5:1.

3/8 GRADE 8 CHAIN

The most popular size and grade chain used in light and medium-duty recovery.

TO FIND THE ULTIMATE LOAD – MULTIPLY THE WORKING LOAD LIMIT BY THE DESIGN FACTOR.

W.L.L. 7,100 lbs X D.F. 4:1 = U.L. 28,400 lbs

TO FIND THE WORKING LOAD LIMIT – DIVIDE THE ULTIMATE LOAD BY THE DESIGN FACTOR.

U.L. 28,400 lbs ÷ D.F. 4:1 = W.L.L. 7,100 lbs

NOTE

Refer to Manufacturers specifications regarding design factors of Shackles. The Design Factor may be 4:1 but could vary. Generally, shackles used with synthetic rigging may have a Design Factor of 5:1

The Design Factor for wire rope and synthetic winch line varies and generally set or determined by the industry using it.