The necessary fall zone has to be taken into consideration while working with fall protection equipment, regardless of the situation.
Impact during an accidental fall must be prevented!
The required fall zone can have a radius between .5 and 10 meters, depending on the system components and placement of the anchors.
The important factors are:
- Placement of the anchors (directly above the worker, and above head height wherever possible)
- Total length of the ropes
- Dynamic stretching of the ropes.
For example: the dynamic pull of a EN1891 rope is 5%!
A wet rope can stretch up to 1.5x more than a dry rope!
- Extension of shock absorbers
= the effective, fall dependent, extension length
→ A lower fall height will only extend the absorber a fraction of the distance
→A specialist should be able to calculate the correct extension length
- Stretching of the harness
- Distance between the attachment point on the harness and the workers shoes
- A safety reserve of 1m
Here are a few example calculations for a safe fall zone:
Example 1: Height safety device with an overhead anchor point
Example 2: 2m rope with an anchor point below the waist
Example 3: 1.5m rope with an anchor point at shoulder height