Bowtie diagrams: A user-friendly risk communication tool - Contractor management case study

Network Rail recognises that more work is required to allow a robust and consistent demonstration that appropriate health and safety risk assessments are being undertaken throughout each stage of the contracting process. In... [ view full abstract ]

Network Rail recognises that more work is required to allow a robust and consistent demonstration that appropriate health and safety risk assessments are being undertaken throughout each stage of the contracting process. In response to this requirement, ERM was engaged to assist IP S&SD with the development of a new risk-based contractor management and assurance process. Bowtie diagrams were selected as a key component of this process to represent:
• Key safety risks associated with rail construction projects (based on lifesaving rules)
• Potential causes and consequences
• Good practice in risk controls/barriers: preventative and mitigating.

To test the suitability of Bowties for risk communication to contractors, three key hazards, each of which is aligned with one or more of Network Rail’s ten Lifesaving Rules, were identified for Bowtie analysis. These, and the specific top events selected were:

Hazard: Working at height - from scaffold, ladders, MEWPS, mobile towers or ledges Top event: Falls from height – to surface

Hazard: Working in vicinity of uninsulated conductors and supply points
Top event: Contact with live/ charged equipment >60V

Hazard: Working on or near the line with a line blockage
Top event: Personnel in path of oncoming train

A one-day Bowtie development workshop was held for each of the hazards selected. These were attended by Network Rail personnel with the required knowledge and expertise of the hazard and associated control measures, ensuring the necessary levels of input and consultation.

Feedback to date on the Bowtie approach has been positive, both within Network Rail and contractor organisations. Bowties provide a method of communicating Network Rail’s expectations about levels of protection to IP contractors, and address the following key requirements:
• Allow contractors to understand risk management requirements in detail and to price jobs accordingly.
• Enable identification of gaps in the control of key risks and facilitate implementation of best practice.
• Can be used by Network Rail as a project safety assurance tool, to check the risk management measures in place against those defined in the Bowtie.
• Demonstrate to the ORR that Network Rail is communicating a clear ‘safety story’ throughout a project.

This paper will describe the Bowtie development process in accordance with Ten Golden Rules (ERM, 2013), including how human factors can be incorporated in a systematic and meaningful way. It will demonstrate how the Bowties developed within this project represent in a clear and accessible manner what constitutes industry best practice with regard to controlling important safety risks in construction projects.