Safe distance to an unprotected roof edge is a common area of misunderstanding when discussing fall protection. To put it plainly—there isn’t a safe distance. In principal, I agree with those who say that as you increase the distance to an unprotected edge, you decrease the probability of a fall. However, it’s important to remember that this is not supported by OSHA 29 CFR 1910 or 1926 (see note below).
The proposed OSHA 1910 regulation specifically addresses this issue: “This proposed standard does not specify a distance from the edge that is considered safe, (i.e., a distance at which fall protection is not required.) Instead, it allows the employer to designate an area in which employees can work without fall protection.”
I believe the misconception of a specific safe distance has surfaced since warning line rules require setbacks from the edge at 6, 10, or 15 feet depending on the circumstances. Also, OSHA compliance officers often do not cite a circumstance unless the worker is reasonably close to an unprotected edge. As you can imagine, this can be very subjective as to the distance that is too close to the edge. Especially considering the clarity provided in the proposed OSHA standards, it is critical to provide fall protection anytime workers are near any unprotected edge.
Most people know that these warning lines are not required to have the same strength as guardrail. However, some people don’t realize that OSHA still considers it a physical barrier, albeit one that will only warn you when you are too close to the edge. And, since some of you may be thinking about this, OSHA does not recognize painting a line on the roof as sufficient fall protection.
Note: 29 CFR 1926 does allow for a safety monitor system for specific tasks although there are additional requirements beyond just using a safe distance to an unprotected edge. Actually, you can have no distance to the unprotected edge and still use the monitor system. If you have ever talked with me about this, you know that I am not in favor of using monitor systems. Contact me if you want to discuss.