Maintworld 1/2018

HSE
... tag
LoTo also includes the corresponding
labelling of the isolation device by means
of a sign or a tag on the lock: Why is the
equipment secured against restarting
and labelled accordingly? Who approved
LoTo? Who carried out LoTo? How long
does the lockout last? Who can provide
additional information?
LoTo is not just about attaching a
lock and a label. It is a comprehensive
programme that has far-reaching consequences
in the company and the handling
of machinery. The goal is a process
with which safe handling of hazardous
energy sources is guaranteed under
normal operating conditions and other
foreseeable conditions.
As is always the case in the field of
Photo: Pilz GmbH & Co. KG
machinery safety, the first step is an assessment
of the existing machines and
energies. Specifically, this includes the
determination and assessment of risks
and hazards, the determination of sources
of hazardous energy, the determination
of cut-off points and the definition
of additional required measures (e.g.
vents, brakes).
Step by Step
At the beginning of the LoTo process, it is
necessary to determine which people are
responsible for LoTo and which people
are participating in LoTo. It is also necessary
to clarify which permissions and approvals
are necessary for the work. Then
a LoTo process tailored to the individual
needs of the company must be created.
The individual steps and responsibilities
etc. are described below.
Generally, a LoTo procedure comprises
the following steps:
1. Assessment and preparation of
the task/work to be performed
on the machinery
2. Handover of the equipment: The
equipment (lock & tag) can be
managed centrally (foreman) or
locally (maintenance engineer)
3. De-energise and lockout plus apply
tag
4. Check point 3
5. Performance of the task, such as
maintenance
6. Approval for release and cancellation
of the disconnection
7. Cancellation of the disconnection
by removing the lockout and
the tag
Lock Out Tag Out
is the systematic
disconnection of
machinery as well as
securing it against
restart. The LoTo
system also includes
the development
of procedures for
machinery isolation
as part of specific
tasks, as well as the
training of machine
operators.
8. Examination
9. Return of the equipment
Who releases the machinery again
depends on the specific process in the
company. Additional components of the
process include the determination of
the purpose, scope and rules of the LoTo
procedure, the description and determination
of the energy control process
to be applied and the description of the
means for the implementation of and
compliance with the LoTo programme.
The disconnection from an energy
supply must be visible (visible interruption
of the energy supply circuits)
or indicated by the clear position of the
manual control (actuator) of the isolation
device. Installation devices such
as manometers or test points are to be
provided to check whether the parts
of the machinery in or on which the
interventions are to be performed are
de-energised.
Assemblies that contain hazardous
stored energy and that can be removed
or disassembled are to be permanently
labelled to warn about the hazards
caused by the stored energy.
Software-supported
documentation
When documenting Lock Out Tag Out
processes, software tools can provide
support to ensure machinery can be
safely de-energised: Job specifications
for dealing with hazardous energy sources
can be produced and documented
simply. Using the PASloto software, it
is possible to produce LoTo reports and
check the company’s own LoTo guidelines.
PASloto produces a poster that
documents a plant’s entire LoTo procedure
and enables images of the machinery
and energy sources to be added to
the Lock Out Tag Out poster.
Employee training is essential
It is critical for success: The personnel
must be trained in this procedure.
This is true for all personnel, irrespective
of their role in the company, as
all employees must understand what
LoTo stands for. Authorised employees
require intensive training and any other
employees involved must be informed
of LoTo and must not undertake any
attempts to restart the machinery. All
employees must understand the significance
of a lock and even employees from
external contractors must be involved
in the training courses. The procedure
is to be implemented across the entire
company.
Finally, the system must be constantly
monitored and checked to ensure that
it functions properly and all elements
are covered. In addition, a predictive detection
of defects and weaknesses of isolating
systems and the implementation
of corrective actions can be enabled. The
ability to react in the event of incidents
should also be determined, as should the
relationship between these incidents
and organisational changes.
The feedback from all participants on
the effectiveness and usefulness of the
(LoTo) process should be continuously
assessed. This is then incorporated into
any continuous process improvement.
There will always be changes, as new
machinery will be added and existing
machinery changed.
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