Bow-tie diagram

A bow-tie diagram is a graphic tool used to describe a possible damage process in terms of the mechanisms that may initiate an event in which energy is released, creating possible outcomes, which themselves produce adverse consequences such as injury and damage. The diagram is centred on the (generally unintended) event with credible initiating mechanisms on the left (being where reading diagrams starts) and resulting outcomes and associated consequences (such as injury, loss of property, damage to the environment, etc.) on the right. Needed control measures, or barriers, can be identified for each possible path from mechanisms to the final consequences. The shape of the diagram resembles a bow tie, after which it is named.[1]

A bow-tie diagram can be considered as a simplified, linear, and qualitative representation of a fault tree (analyzing the cause of an event) combined with an event tree (analyzing the consequences),[2] although it can maintain the quantitative, probabilistic aspects of the fault and event tree when it is used in the context of quantified risk assessments.[3]

Bow-tie analysis is used to display and communicate information about risks in situations where an event has a range of possible causes and consequences. A bow tie is used when assessing controls to check that each pathway from cause to event and event to consequence has effective controls, and that factors that could cause controls to fail (including management systems failures) are recognized. It can be used proactively to consider potential events and also retrospectively to model events that have already occurred, such as in an accident analysis. The diagram follows the same basic principles as those on which fault tree analysis and event tree analysis are based, but, in being far less complex than these, is attractive as a means of rapidly establishing an overall scope of risk concerns for an organisation, only some few of which may justify those more rigorous and logical methods.[4][5]

Bow-tie diagrams are used in several industries, such as oil and gas production, the process industries, aviation, and finance.[1][6]

  1. ^ a b Center for Chemical Process Safety (CCPS); Energy Institute (EI) (2018). Bow Ties in Risk Management. Hoboken, N.J.: John Wiley & Sons. ISBN 9781119490388.
  2. ^ IEC; ISO (2019). Risk Management – Risk Assessment Techniques. IEC 31010 (2.0 ed.). Genève, Switzerland: International Electrotechnical Commission. ISBN 978-2-8322-6989-3.
  3. ^ de Ruijter, A.; Guldenmund, F. (2016). "The Bowtie Method: A Review". Safety Science. 88: 211–218. doi:10.1016/j.ssci.2016.03.001. eISSN 1879-1042. ISSN 0925-7535.
  4. ^ IEC; ISO (2019). Risk Management – Risk Assessment Techniques. IEC 31010 (2.0 ed.). Geneva: International Electrotechnical Commission. ISBN 978-2-8322-6989-3.
  5. ^ Cite error: The named reference Viner was invoked but never defined (see the help page).
  6. ^ "Introduction to Bowtie". UK Civil Aviation Authority. Archived from the original on 7 December 2023. Retrieved 17 March 2024.