When rigging is used to support workers, what percent of the ultimate breaking strength must the working load not exceed?

In the context of rigging used to support workers, safety is paramount. The correct percentage that the working load must not exceed is 10% of the ultimate breaking strength. This guideline ensures that there is a significant safety margin built into the rigging system. By limiting the working load to this percentage, it accounts for potential dynamic forces that may occur during use, such as swinging, bouncing, or unexpected movements.

Using a safety factor allows for the unavoidable wear and tear on equipment as well, which can affect the rigging's overall strength. In various industries, adhering to this percentage helps to prevent failures that could lead to severe accidents or injuries.

When considering the other percentages, it is clear that they do not provide the same level of safety assurance. For example, allowing a working load to be 25%, 15%, or 5% of the ultimate breaking strength does not maintain the critical safety margins necessary when supporting workers. Therefore, the 10% threshold is established as a best practice in rigging safety standards.