Slings must be removed from service if hooks are cracked or have been opened more than what percentage of their normal throat opening?

Slings must be removed from service if hooks are cracked or have been opened more than 15% of their normal throat opening. This is because a hook that is opened excessively or is cracked poses a significant safety risk. The integrity of the hook is critical in maintaining the secure connection between the load and the lifting device. If the hook is deformed, it may not be able to properly support the load, increasing the chance of failure during lifting operations.

The 15% threshold is established based on safety standards which aim to prevent accidents and ensure reliable lifting operations. By mandating removal of hooks that are opened beyond this percentage, operators help ensure that only equipment in safe working condition is utilized, thereby protecting both the lift operators and anyone else in the vicinity.