Permanent Warning Lines

Permanent warning lines clearly mark a defined work area in rooftop applications, and are best utilized in conjunction with additional fall protection systems in place. Although these systems are permanently installed to better withstand the elements, it is important to remember that these systems do NOT physically restrain workers from traveling into dangerous areas nor do they arrest falls. Before utilizing a warning line fall protection system, be sure to contact qualified fall protection company to explore all potential options to keep your employees safe while working at heights.

Design Considerations

Warning Line Fall Protection Design Considerations A warning line system consists of a cable threaded through vertical posts spaced at 40’ intervals. The cable must be between 34”-39” above the surface of the roof, with flags spaced every 6’. Although many workers prefer the use of warning lines because they allow for unencumbered ease of access, a warning line does not actively restrain a worker from coming into close proximity with an unprotected leading edge and the system is NOT designed to arrest falls. For these reasons, it is considered a best practice to explore an alternative means of fall protection in addition to the visual reminder that is provided by a warning line. DFP fall protection engineers will gladly explain the both the pros and cons of warning line use to ensure the safety of your workers and the OSHA compliance of your facility.

OSHA Regulations

1926.502(f) 'Warning line systems.' Warning line systems [See 1926.501(b)(10)] and their use shall comply with the following provisions:
1926.502(f)(1) The warning line shall be erected around all sides of the roof work area.
1926.502(f)(1)(i) When mechanical equipment is not being used, the warning line shall be erected not less than 6 feet (1.8 m) from the roof edge.
1926.502(f)(1)(ii) When mechanical equipment is being used, the warning line shall be erected not less than 6 feet (1.8 m) from the roof edge which is parallel to the direction of mechanical equipment operation, and not less than 10 feet (3.1 m) from the roof edge which is perpendicular to the direction of mechanical equipment operation.
1926.502(f)(1)(iii) Points of access, materials handling areas, storage areas, and hoisting areas shall be connected to the work area by an access path formed by two warning lines.
1926.502(f)(1)(iv) When the path to a point of access is not in use, a rope, wire, chain, or other barricade, equivalent in strength and height to the warning line, shall be placed across the path at the point where the path intersects the warning line erected around the work area, or the path shall be offset such that a person cannot walk directly into the work area.
1926.502(f)(2) Warning lines shall consist of ropes, wires, or chains, and supporting stanchions erected as follows:
1926.502(f)(2)(i) The rope, wire, or chain shall be flagged at not more than 6-foot (1.8 m) intervals with high-visibility material;
1926.502(f)(2)(ii) The rope, wire, or chain shall be rigged and supported in such a way that its lowest point (including sag) is no less than 34 inches (.9 m) from the walking/working surface and its highest point is no more than 39 inches (1.0 m) from the walking/working surface;
1926.502(f)(2)(iii) After being erected, with the rope, wire, or chain attached, stanchions shall be capable of resisting, without tipping over, a force of at least 16 pounds (71 N) applied horizontally against the stanchion, 30 inches (.8 m) above the walking/working surface, perpendicular to the warning line, and in the direction of the floor, roof, or platform edge;
1926.502(f)(2)(iv) The rope, wire, or chain shall have a minimum tensile strength of 500 pounds (2.22 kN), and after being attached to the stanchions, shall be capable of supporting, without breaking, the loads applied to the stanchions as prescribed in paragraph (f)(2)(iii) of this section; and
1926.502(f)(2)(v) The line shall be attached at each stanchion in such a way that pulling on one section of the line between stanchions will not result in slack being taken up in adjacent sections before the stanchion tips over.