When must personal fall arrest systems be used?

Personal fall arrest systems are crucial for ensuring safety when working at heights, particularly in situations where there is a significant risk of falling. The correct answer acknowledges that these systems must be employed specifically when working on poles, towers, or similar structures that exceed 4 feet above ground level. This requirement is grounded in safety regulations and industry best practices that recognize the increased risk associated with elevated work environments.

The emphasis on a height of more than 4 feet aligns with occupational health and safety guidelines that mandate the use of fall protection when working at elevations where the potential for falls exists. This rule helps to mitigate serious injuries that can occur from falls, elevating the overall safety of workers engaged in tasks at height.

In contrast, while working on a roof may indeed necessitate the use of fall arrest systems, the requirement is more specifically outlined where the risk of falling is quantifiable, such as with poles or towers. Working in confined spaces generally has separate safety measures due to different hazards rather than specific fall risk and may not require fall arrest systems in every instance, depending on the confines. Therefore, while it's important to maintain awareness of safety protocols at all times when heights are involved, this option encapsulates the specific regulation that applies to structures above the designated height