Fc < 6 kN Fc < 6 kN Fc > 6 kN Fc > 6 kN
Fc < 6 kN Fc < 6 kN Fc > 6 kN Fc > 6 kN
GENERAL PRINCIPLES OF WORK AT HEIGHT
Clearance
disregarded
Clearance
Lanyard with
ABSORBICA-I or Y
energy absorber
JANE or PROGRESS lanyard
without energy absorber
Example for 100 kg
Suspension
Work Positioning
Fall Arrest
The user is working while suspended
when they no longer have any weight
on their feet, but are supported primarily
by the harness. The load is thus shared
between the waistbelt and the leg loops/
seat.
A work-positioning system supports
the user and allows them to be precisely
positioned with the weight on their feet.
This system is not designed to arrest a
fall; the user must keep their body weight
on the positioning system.
The work-positioning system must be
used together with a fall-arrest system.
Warning
• You must have understood and retained the information from your products’ Instructions for Use to be able to apply the techniques
presented in this document
• Learning appropriate techniques and methods of protection is your own responsibility
Petzl solutions are given for information purposes only, with no guarantee of their effectiveness in your specific working situation.
The relevance of these solutions varies by context, so always carry out your own risk assessment in the field.
• Mastering the techniques presented here requires specific training and practice. Work with a specialized organization for all of
your training activities
The fall-arrest system is a belay system
that is independent of the means of
progression or work positioning.
The fall-arrest system prevents the user
from falling to the ground in the event
of a fall. Its role is to arrest the fall while
limiting the impact force experienced
by the user. It must therefore be used
with enough clearance to allow for an
unobstructed fall.
General Information About Falls
The risk of falling is a key concept to master when
working at height. The severity of a fall depends on
independent factors:
• The weight of the user, including equipment
The greater the weight, the more energy to be
dissipated during the fall.
• The length of the fall
The longer the fall, the more energy to be dissipated
during the fall. The risk of hitting an obstacle is also
greater.
• The position relative to the anchor
When the worker moves above their anchor,
the severity of the potential fall increases. The fall
factor concept is sometimes used to describe the
worker’s position relative to the anchor and the severity
of the fall. This concept applies to climbing, restraint,
or work-positioning situations, when a dynamic rope
lanyard is used.
Precautions for the type of system used:
the Instructions for Use specify the limitations
on use of equipment, particularly in terms of
fall distance and the worker’s position relative
to the anchor.
Restraint
A restraint system limits
the work zone, to help
prevent the worker from
entering an area that
may present a fall risk.
This system is not
designed to arrest
a fall from height.
Impact Force
A fall-arrest system helps limit the impact force
sustained by the user.
It is typically made up of an energy absorber
that tears in order to limit the forces over a
given stopping distance.
A dynamic rope lanyard has a low capacity for
energy absorption. Its use requires taking great
precautions: reducing the potential fall distance
and staying in a work position below the anchor.
A webbing lanyard or a cable with no capacity for
energy absorption cannot be used to arrest a fall.
Clearance
Clearance is the minimum amount of clear space
below the user that prevents the user from hitting
an obstacle in the event of a fall.
Clearance takes into account:
- Weight of the user
- Length of the fall
- Tearing length of the energy absorber
- Average height of the user
- Safety margin of 1 meter
Clearance Value
The tearing length of the energy absorber,
depending on the fall, can only be known based
on the manufacturer’s information; this is why a
clearance estimate is suggested in the Instructions
for Use for each fall-arrest device.
Anticipating the Means of Rapid Evacuation
• Limiting the effects of inert suspension
In the event of a fall where the worker loses consciousness or is
incapacitated, inert suspension in the harness presents a mortal
danger requiring an urgent response. Work teams must be equipped
and trained to quickly evacuate an injured team member.
• Evacuating a victim without assistance
Procedures for evacuating workers should be determined whenever
a new worksite is established.
Releasable systems can be created when installing work ropes to allow
evacuation from below.
Working alone must be prohibited: a worker may find themselves alone
at height, but at least one person trained in evacuations should be
present and equipped on site.
I n f o r m a t i o n i s n o n-e x h a u s t i v e. R e f e r t o t h e o t h e r p a g e s a s w e l l a s t h e I n s t r u c t i o n s f o r U s e a n d t e c h n i c a l m a n u a l s. T e c h n i c a l t r a i n i n g i s e s s e n t i a l.
To learn more about calculating
clearance, see the technical
information available at Petzl.com