the safety catalogue - page 408

personal protective devices - when used in a professional manner - provide protection against risks arising from
differences of height (fall from height or into deep).
Purpose of fall arrest systems
- prevent falling, safe connection to an attachment point
- stop a person already falling as soon as possible and with the least possible energy being transferred (arrest force max.
6 kN)
- keeping the fall victim in adequate posture after the fall until being rescued
Defining required fall clearance under the workplace
Subject to the location of a fixed anchorage point and the length of the lanyards and connectors above the worker, it is
mandatory to have a defined fall clearance under the workplace to prevent the user from hitting the ground or any objects
while falling.
The following data should be considered for the calculation of minimum required fall clearance:
Prior to using the harness, a suspension test should be performed under safe circumstances without the risk of falling to
make sure that the size of the body harness is set correctly for the comfortable and safe work activity.
If the system used is comprised of a guided type fall arrester, the braking distance of the equipment - which is required by
the standard to be less than 1 meter - and the determined elongation of the flexible anchored rope (approx. 5%) should also
be considered. Therefore, the longer the rope above the worker, the larger fall clearance should be provided below the user
when using such systems. The exact distance is specified in the user manual of the protective equipment.
Putting on the body harness
safety distance from ground after arresting the fall: 1 meter
installation of the fixed anchorage point: the attachment
point is required to be above the user to reduce the fall thus
preventing the fall arrest equipment from getting below the
attachment point of the body harness.
length of the roped energy absorber including connecting
components and carabiners: max. 2 meters according to
elongation of energy absorber after the stitches have been
dissolved: maximum 1.2 meters
the standard provides for an average distance of 1.5 meters
between the attachment point of the body harness and the sole
of the user and is recommended to add further 20 centimeters
to allow for the movement of the attachment point of the
body harness following exertion of the arrest force. Total: 1.7
meters. If the body harness used has an extension to the rear
attachment point, allow for an additional 0.3 meter to it.
the strap
through the
of the
8cm (min)
Fall clearance (if A=0)
Fall clearance (if A=-3)
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