Fall Arrest Anchorage Requirements
I saw an article recently written by an engineer complaining about the 5000 pound anchorage for fall protection. He was troubled that while OSHA mentions identifying a 5000 pound Anchorage, they do not state who needs to identify the anchorage. Typical contractor safety plans and construction safety programs in general, comply with and use this 5000 pound rating in the fall protection and safety chapters. As a professional engineer, he was prohibited by law from designing a certified anchorage without proving that the existing structures adequate. Basically he was stating to be legal he would need to perform required calculations not only on the new anchorage, but on the structure itself to be legal. His question was, “why do OSHA and ANSI allow someone who’s not a professional engineer to do something a professional engineer trained in the analysis of structures cannot do? “
I think he’s missing the point about anchorage in construction. OSHA allows for a layperson, i.e. craftworker, who is not an engineer to look around and “eyeball” a structure for potential 5000 pound anchor points. The worker has to have a good faith belief that the anchorage can hold 5000 pounds. However OSHA allows an engineer to design in anchor that is twice the anticipated load. Personal fall arrest systems with shock absorbing lanyards have a typical load applied to them in the fall of less than 900 pounds. Therefore, an engineer could conceivably design in anchor that is 1800 pound strength. The requirement for a worker to look around and find a 5000 pound anchor point is almost 3 times as strong as what is actually required to arrest the worker in a typical situation. A fall protection safety program with this criteria. I believe is sufficient.
If we would require an engineer to verify every point of fall protection. It would be too large a burden for constructability. However, we need to keep mindful of assuming that the overall structure can accommodate a 5000 pound anchor point, even if we are using a store-bought anchor. For instance, while there are several 5000 pound rated anchors for residential would trusses, many trusts manufacturers, ardent putting out disclaimers stating that there would trusses are not designed for these and on anchor points. That is, the wood trusses are designed for snow load, not personal fall arrest systems. Accordingly, scaffolds manufacturers clearly state that their products are not designed or engineered to accommodate personal fall arrest system anchor points. The contractor and craftworkers alike need to be aware of the limitations of the structures they are attaching to. These are items that should be part of any good overall safety program, and revealed in a fall hazard analysis on a construction project.
Even traditional structural steel projects may have limitations. The most recent steel erection rule from OSHA now requires that to use bar joists as fall protection anchor points, it does need to be verified with the engineer of record for that structural steel project. This is a departure from previous attitudes that any “red steel” was sufficient for anchorage.
While I think the 5000 pound anchorage rule as it exists is a good one, however I do have a problem with the fall restraint anchorage values. I will cover that in another article.