A Warning line system provides a practical way to define a controlled area around roof work and alert workers when they approach an unsafe edge. It is commonly used on low-slope roofs where workers need to perform tasks away from unprotected edges. A properly installed system creates a visible boundary while allowing workers to move freely within the designated work area.

Warning lines can be especially useful during roofing, maintenance, inspection, and construction activities. The system should be installed according to applicable safety requirements, with appropriate stanchions, lines, and warning indicators. Combining a Warning line system with proper worker training and other fall protection measures can help reduce the risk of accidental falls and improve overall roof safety.