It’s crucial that any roof anchor point is positioned with a view to avoiding potential dangers, however unlikely. Examples of such risks are the danger of swing down, and swing back and severing of the arrest line
Correct Installation of Roof Anchor Point
Swing down: an arrest line should not be anchored so there’s any possibility that a falling person could fall off the roof and hit the ground. The length of the arrest line is also important here, as well as the anchor point location.
Swing back: an anchor point installation that allows the arrest line to swing a falling person back to hit the perpendicular edge of the building or structure.
Care must also be take to avoid a sharp roof edge from severing the arrest line altogether.
If any of these scenarios are likely, reconsider individual fall arrest. There are other height safety solutions that would work in these cases