Horizontal lifelines require special attention during design and installation to: (1) limit the distance the worker can fall (a greater sag in the line can mean a farther fall); and (2) minimize the forces on the connectors at the anchorage (a greater sag in the line can mean lower forces on the anchorage connectors at either end). A qualified person must supervise the horizontal lifeline’s design, installation, and use. Depending on their geometry and sag angle, horizontal lifelines may be subjected to greater loads than the impact load imposed by an attached component. When the horizontal lifeline’s sag is less than 30 degrees, the impact force imparted to the lifeline by an attached lanyard is greatly amplified. For reference, a 15-degree sag angle amplifies the force approximately 2:1. A 5 degree sag angle amplifies the force approximately 6:1.