Horizontal Lifeline Systems, also known as HLL systems, are utilized in many of the fall arrest and fall restraint systems given great utility and flexibility. Horizontal lifeline systems are common in work areas lacking overhead anchor points available for personnel tie–off. In simplest form, the horizontal lifeline consists of a cable attached to two or more anchor points on a roof-top, crane runway, bridge or outdoor construction site, or any other elevated work area that poses a fall risk to personnel.
When used in combination with personal protective equipment, a horizontal lifeline can arrest a fall, limiting the amount of force that is transferred both to the worker and the fall arrest system. This same combination of horizontal lifeline, body harness, and lanyard can also serve as a fall restraint system, limiting the At Risk Worker’s (AWR) ability to move close enough to fall over an unprotected leading edge. The fall restraint and fall arrest properties of horizontal lifelines make the HLL an integral part of many fall protection systems.