How do you calculate the working load limit for a sling configured with multiple legs?

How do you calculate the working load limit for a sling configured with multiple legs?

• A. WLL per leg, multiply by the number of legs, and apply derating for leg angles; ensure the total load does not exceed the system’s safe capacity.
• B. Add WLL of each leg without derating.
• C. Use the highest WLL among legs.
• D. WLL is equal to rated capacity of one leg.

Answer: (A)

When a sling uses multiple legs, the load is shared among the legs, but the tension in each leg goes up as the legs spread from vertical. To find the sling’s working load limit for a multi-leg setup, take the WLL of a single leg, multiply by the number of legs, and then apply a derating for the leg angles. In practice, the total allowable load is W_allowable = number_of_legs × WLL_per_leg × cos(theta) (for symmetrical angles), where theta is the angle each leg makes from vertical. If the legs are vertical (theta = 0), cos(theta) = 1 and you get the maximum, but as the angle increases, cos(theta) decreases and the total WLL drops. Always ensure the actual load does not exceed this derated total or the system’s safe capacity.

When a sling uses multiple legs, the load is shared among the legs, but the tension in each leg goes up as the legs spread from vertical. To find the sling’s working load limit for a multi-leg setup, take the WLL of a single leg, multiply by the number of legs, and then apply a derating for the leg angles. In practice, the total allowable load is W_allowable = number_of_legs × WLL_per_leg × cos(theta) (for symmetrical angles), where theta is the angle each leg makes from vertical. If the legs are vertical (theta = 0), cos(theta) = 1 and you get the maximum, but as the angle increases, cos(theta) decreases and the total WLL drops. Always ensure the actual load does not exceed this derated total or the system’s safe capacity.