When should hooks be removed from service according to B30.10?

Removing hooks from service when the throat opening exceeds 5% of the original throat opening is based on the safety standards outlined in ASME B30.10. This standard aims to ensure the integrity and safety of lifting equipment. A hook's throat opening is critical to its ability to securely hold loads. Any significant alteration, such as an increase in the opening size, can compromise load stability and increase the risk of slippage or failure during lifting operations.

The threshold of 5% is set to act as an early warning sign for potential wear or damage that can lead to unsafe conditions. Maintenance practices dictated by these standards help prevent accidents that could arise from the use of degraded hooks. Testing for integrity and regularly monitoring wear are essential to align with these safety guidelines, emphasizing the importance of prompt inspection and removal from service when wear limits are reached to protect operators and ensure a safe lifting environment.