Bowtie Elements

The different parts that make up this risk assessment model

One of the main strengths of the bowtie is the ease with which it may be understood and interpreted once the reader has a basic understanding of what the diagram elements represent and how they interact.

The bowtie model and the process by which it is put together follows eight basic steps.

It is worth noting that the Bowtie terminology differs slightly from Safety Management Systems, for example the term ‘Hazard’.  How the terminology is linked between bowtie and SMS is detailed in the section called Implementing bowtie into Safety Management Systems.

HazardStep 1 to build the bowtie focusing on aspects with the potential to cause injuries, damage or loss
Top EventStep 2 which describes the undesired system state
ThreatsStep 3 showing possible direct causes
ConsequencesStep 4 in building the bowtie showing possible direct outcomes resulting in loss or damage
Prevention ControlsStep 5 to the bowtie to add any measures taken to prevent the threat and top event
Recovery ControlsStep 6 to the bowtie to add any measures taken to prevent the consequences
Escalation FactorsStep 7 showing a condition that affects the performance of the controls in place
Escalation Factor ControlsStep 8 is adding any measure taken to prevent the escalation factors impacting the controls