ASME B30.10 requires that a hook with distortion increasing throat opening by 5 percent (not to exceed 4 inches) shall be:

• A. Repaired
• B. Replaced
• C. Reused
• D. Retired

Answer: (B)

A hook’s throat opening is a critical dimension that directly affects how load is carried and how the hook engages with the sling and load. When distortion causes the throat opening to increase by 5 percent (even if the total change is capped at 4 inches), the hook’s geometry is no longer within its safe operating limits. This kind of distortion can concentrate stresses, hide cracks, and alter the load path in ways that weaken the hook and raise the risk of failure under load. Because safety-critical performance can’t be reliably restored by repair or straightening, the standard requires replacing the hook to ensure a known, safe strength and geometry. Repaired or reused hooks would continue to carry the compromised geometry and could fail, and retirement isn’t the specified corrective action for this condition. Replacing the hook restores safety and capacity.