What Does
Warning Line System Mean?
A warning line system is a barrier erected to warn employees of an unprotected leading edge. It costs of flags attached to ropes suspending on a series of stanchions (posts that stand upright and don’t fall over easily).
The Occupational Safety and Health Administration (OSHA) only allows the use of warning line systems on low-slope roofs.
Safeopedia Explains Warning Line System
Unlike guardrails, warning lines will not stop someone from falling. Rather, they remind workers of the presence of fall hazards and demarcate the area where the risk of falling are higher.
OSHA Requirements for Warning Line Systems
Work being performed at less than 6 feet from the edge of a roof requires the use of personal fall arrest systems (PFAS), safety nets, or guardrails. As per OSHA 29 CFR 1910.28(b)(13)(ii), when work is being performed on low-slope roofs, and the work is of temporary nature and infrequent, a warning line system can be used to establish a designated working area.
To be OSHA compliant, a warning line system must satisfy the following conditions:
- It must be used at least 15 feet from the edge
- It must meet or exceed OSHA’s setup requirements
- No activity must take place between the edge and warning line
- Employees must not go past the warning line
OSHA CFR 1926.502(f) stipulates the setup requirements for warning line systems, including:
- A minimum tensile strength of 500 lbs.
- Flags placed no more than 6 feet apart
- Lowest part of the line must not sag below 34 inches from the walking surface
- Once installed, stanchions must be able to resist at least 16 lbs. of force
Warning Line Distance from Leading Edges
The minimum distance between the warning line and the nearest leading edge depends on the type of work being conducted on the roof:
- Roofing work: 6 feet minimum distance
- Work involving mechanical equipment: 10 feet minimum distance in any direction toward which the equipment is moving – otherwise, 6 feet minimum distance
- Non-roofing work: 15 feet minimum distance
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