When workers use personal fall arrest systems on flat commercial roofs-like HVAC technicians or solar panel installers-they usually tie off to a permanent roof anchor. These are usually stainless steel D-rings welded to a base plate that is bolted or epoxied directly into the structural concrete of the building. Because these anchors are permanently bolted to the roof and look like indestructible chunks of metal, they are rarely treated with the suspicion they deserve. Workers walk up, clip their lanyard to the D-ring, and trust it with their life. This is a fatal mistake.
The building is alive. Commercial roofs experience massive temperature swings, causing the concrete to expand and contract. The building itself sways slightly in high winds. And massive industrial HVAC units vibrate constantly right next to these anchors. Over a period of five to ten years, this constant movement works against the anchor. If it is a bolt-in anchor, the expansion anchors inside the concrete slowly loosen. If it is an epoxy anchor, the vibration microscopically fractures the concrete holding the epoxy plug, or the UV rays from the sun degrade the exposed epoxy at the surface.
Visually, the anchor looks perfect. The steel isn't rusted, the base plate is flat. But underneath, the anchor is holding on by a thread. When a 250-pound man falls three feet and the lanyard snaps tight, generating thousands of pounds of force, that loose anchor will simply rip out of the concrete like a tooth being pulled.
You cannot trust a visual inspection on a roof anchor. Every single time you tie off to a permanent roof anchor, you must perform a physical manipulation test. Walk up to the D-ring, grab it with both hands, and try to aggressively rock it side to side, and try to pry it upward. If there is even a millimeter of movement, if you feel a subtle "click" or grinding sensation from inside the concrete, that anchor is compromised and must be immediately taken out of service and tagged out. Furthermore, check the gap between the base plate and the roof membrane. If the roof tar or rubber membrane has separated from the base plate, water has been getting inside, rusting the internal bolts, or degrading the concrete. Never clip a lanyard to an anchor that you haven't physically tried to destroy with your bare hands first.
