Clearance or clear distance required under the operator’s feet in the event of a fall ?

This is a crucial concept for the operator’s safety:
This is the space required under the operator’s feet for a given fall arrest system, in order to arrest the operator's fall and prevent the operator from hitting the ground or an obstacle during the fall.

To determine this distance, all the elements involved in arresting the fall must be taken into account: the fall height, the elongation of the absorber (if the system is equipped with one), etc... A safety margin of 1 metre should be added to allow for the elasticity of all system components during the fall. This value is specified by the manufacturer in the system user manual or by i-beSafe. It can be expressed under the anchorage point or under the operator’s feet.

Therefore, when analysing the work situation, you should note that:
✓ clearance depends on the Fall Factor (i.e., the position of the operator relative to the anchorage point);
✓ It is essential to be aware of the value of the required clearance specific to each system and to compare it with the space available for the particular work situation.

For a lanyard with energy absorber (Fig. 1), the clearance is expressed below the anchorage; it can also be considered under the operator's feet (work area)

For retractable fall arresters, we ONLY consider the clear distance under the work area and not the clearance.

Why? Because, depending on the type of retractable fall arrester, the position of the anchorage point may vary in distance from the operator, so for retractable fall arresters it is more effective to refer to clear distance under the work area.

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antichute

The concept of Fall Factor

facteur de chute

Note: In i-beSafe, the values provided in Factor 0 actually correspond to a fall factor of 0.3. For greater simplicity, we have chosen to communicate with Factor 0..

Concept of a sharp edge

In certain work configurations, there may be a significant risk of friction on a sharp surface: steel roof framework, steel roof sheet, grating or concrete parapet, for example. Likewise, on certain fragile roofs or terraces (fibre cement roofs), it is necessary to consider the risk of passing through the surface, which could become sharp.
There are test protocols that verify the capacity of certain systems to withstand the arrest of a sharp-edge fall.
Consequently, Kratos Safety offers ranges of equipment for retractable fall arresters, fall arrest lanyards and sliding fall arresters on a rope anchor line that meet these requirements. These are often referred to as “edge” or “sharp edge” with the following identification:

 

 

Sharp edge, Factor 2

Warning: For an equivalent product, the clearance required under the operator's feet when falling over a sharp edge or in Factor 2 differs greatly from that required when falling vertically.