Wire Rope Design Factor

Wire rope must be designed to have in relation to the equipment s rated capacity a sufficient minimum breaking force and design factor so that compliance with the applicable inspection provisions in 1926 1413 will be an effective means of preventing sudden rope failure.

Wire rope design factor. Wire rope design factor. Operating loads not to exceed 20 of catalog breaking strength operating loads may have to be reduced when life limb or valuable property are at risk or other than new rope is used. Api spec 7k drilling and well servicing equipment upstream segment fifth edition june 2010 august 2010. The ratio between documented minimum breaking strength and the working load limit as applied to wire rope and slings.

And is working under an operating stress of 20 000 lbs it has a rope strength design factor of 5. The design factor takes into consideration both normal rope wear and potential stresses in various applications. Wire rope is not termed oversize until its diameter exceeds the allowable maximum. Unirope synthetic slings are manufactured to ensure a design factor of at least 5 1.

The rope strength design factor is the ratio of the rated strength of the rope to its operating stress. This design factor is a factor which is divided into the nominal strength of a sling to arrive at the wll or rated capacity. A design factor of 10 is usually chosen when wire rope is used to carry personnel. If a particular rope has a rated strength of 100 000 lbs.

The design factor being both the ratio between the minimum breaking load of the rope and the rated capacity rc tells at what percentage of its ultimate strength a wire rope is operating. Wire rope strength design factors and physical properties the rope strength design factor is the ratio of the rated strength of the rope to its operating stress. This term should not be confused with design safety factor defined in 3 1 5. Wll and design factor.

A design factor of 5 is chosen most frequently for wire rope.