What safety measure is required when working on a flat roof over 6 feet high?

When working on a flat roof that is more than 6 feet above ground level, it is essential to implement multiple layers of safety measures to protect workers from the risk of falls. In this context, all the options provided—guardrails, safety nets, and personal fall arrest systems—are recognized as effective safeguards in construction safety practices.

Guardrails are constructed barriers that help prevent workers from falling off the edge of the roof, providing a physical barrier that can greatly reduce the risk of serious injury. Safety nets are installed beneath the work area to catch any workers who might fall, offering a secondary protection mechanism. Personal fall arrest systems, which include harnesses and lanyards, secure workers to a fixed point to prevent them from falling more than a certain distance.

By requiring one or more of these safety measures, the regulations ensure a comprehensive approach to fall protection on elevated work sites, thereby enhancing the safety and well-being of workers. This collective requirement significantly minimizes the chances of accidents and injuries associated with working at heights.