UNEXPLODED ORDNANCE - Wind Energy Network

RISK MANAGEMENT
The
BOW-TIE
Method
An Elegant Solution
In a previous issue, Risktec discussed
the steps of an effective risk
management process and highlighted
the importance of risk assessment/
analysis within this process. A number
of differing techniques are available for
assessing or analysing risk (e.g. risk
assessment matrices) and in this issue,
Risktec focuses upon a powerful and
increasingly popular risk assessment
technique, the Bow-Tie method.
What is a Bow-Tie
The Bow-Tie method, so called because
it describes the management of risk in
the shape of a bow-tie, is an extremely
powerful way of clearly illustrating how
risk is being managed within an operation,
business etc. It helps ensure that risks
are managed rather than just analysed,
partly by going beyond the usual risk
assessment ‘snapshot’ and highlighting
the links between risk controls and
management systems.
A bow-tie diagram provides a readilyunderstood
visualisation of the
relationships between the causes of
business upsets (hazards which, if
realised, could compromise business
objectives e.g. impact on health, safety,
the environment, operations etc.), the
escalation of such events, the controls
preventing the event from occurring and
the preparedness measures in place to
limit the impact (see Figure 1). The power
of a bow-tie diagram is that it provides an
overview of multiple plausible scenarios in
a single picture.
Building the Bow-Tie
A bow-tie diagram is built by asking a
structured set of questions in a logical
sequence (see Figure 2). The completed
bow-tie illustrates the hazard, its causes
and consequences, the controls to
minimise the risk, and a list of the critical
tasks undertaken to ensure ongoing
integrity of these controls.
Bow-ties are best constructed via
facilitated workshops involving people who
are regularly confronted with the risks.
This is proven to be the most effective way
of identifying real controls and capturing
current practice. Honesty is an essential
ingredient during these sessions if any
weaknesses in controls are going to be
uncovered. To encourage honesty, the
workshop needs to be run in an open and
engaging fashion, and an independent
facilitator can often help to create such an
environment.
To provide a practical example of a
completed bow-tie, we can again look
at our multi-purpose “Tiger in Cage”
analogy. In this example, wild animals (i.e.
tigers) are the hazard, with the top event
(i.e. when control of hazard is lost) being
tiger escape from the cage. The threats,
consequences, barriers and recovery
preparedness measures for this scenario
can be easily understood at a glance as
illustrated in Figure 3.
Figure 1: The Bow-Tie
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