There are two key aspects of fall protection; one is preventing falls from happening in the first place, the second is fall arrest, or stopping falls that do occur. It’s easy to slip into the trap of thinking that all you have to do to ensure safety is stop the falling person from hitting the ground, but this is a long way from being true.
A worker falling on a slack static line can be killed by the sudden shock to the body when the line goes tight. When anchored with a fully static line like a steel cable the safe fall distance is very short. With static and semi-static rope it’s greater, and with stretchy dynamic rope a worker can easily take a significant free fall with no ill effects. However, the more stretch in the line, the greater the chance of hitting the ground or another obstacle. Modern arrest systems use shock absorbers to take the force out of a long fall. These are absolutely crucial for safety if a serious fall is a possibility.
Obstacles in the fall path must also be considered. Sharp edges, scaffolding and protruding beams can cause serious injuries. Anything that sticks out into the free space where workers may fall is a danger when working at height. The swing must also be accounted for. If a worker is to fall off an edge and straight down for 5m they may be completely safe. If they fall 2m and pendulum into a wall they probably won’t be. If you have any doubts about your arrest systems, get expert help before a fall occurs.