Application of the bowtie model in normalized epidemic prevention and control

^{Click here to enlarge the bowtie diagram.}

In this bowtie diagram, the top event, threats, and consequences are common throughout the world. The hazard is Working and living in an environment with COVID-19, and the top event is Infection of personnel. Contact with people, objects, and vehicles carrying the COVID-19 virus are threats displayed on different scenario lines, because their corresponding controls are different. Consequences are death or poor prognosis after individual infection and multiple infections resulting in clustering emerges of the epidemic.

The key controls are targeted to control the pandemic for overseas branches of this oil company. Some controls on the bowtie diagram are universal, such as personal protection, auto-immune system, medical assistance system, and epidemiological investigation + isolation. This bowtie furthermore shows Chinese best practices, such as closed-off (sealed off) management and grid control measures.

Closed-off management is a control placed on the left-hand side of the bowtie diagram. It effectively isolates people, objects, vehicles, and other (external) health threats that carry the virus outside the physical perimeter (in a normally closed state). An example of a physical perimeter is the wall of a factory.

Closed-off management is carried out through strict perimeter management, including access control. External threats are thus effectively blocked at the outside of the physical perimeter. Doing so, a safe and hygienic working and living environment is created for the personnel in the internal area of the physical perimeter (also called closed management area). This control can prevent all possible threats in the bowtie diagram, hence it is very effective. The oil company has formulated many specific rules and regulations to support this control.

Grid control is placed on the right-hand side of the bowtie diagram, and is an important supplement to closed-off management. A grid is usually a specific area divided according to specific purposes within a closed management area. Grid management control restricts different personnel activities between different areas. Generally, grid control is developed based on top of closed-off management, but sometimes it can be used separately. Grid control can effectively prevent multiple infections resulting in clustering emerges of the epidemic.

Furthermore, this bowtie diagram also shows the escalation factors of some controls. For example, psychological anxiety negatively impacts the defense function of autoimmunity, and insufficient nucleic acid detection capacity can reduce the capacity of the medical rescue system. Once these influencing factors reduce the effect of controls, the company will take relevant countermeasures against degrading factors based on this bowtie diagram. Since these countermeasures are not directly impacting the major scenarios, we do not include them in this bowtie.

The normalized epidemic prevention and control bowtie model is an application of the bowtie method used in process safety management for COVID-19 risk. It is simple, generic, and clear. It facilitates risk management in a structured and systematic way. If you are interested in specific information about this bowtie, please read the original article in Chinese. Due to copyright, you can only read it in the online magazine ‘Labor Protection’ via www.esafety.cn/ (see issue number in the screenshot below), or search and download it via cnki.net.

^{© CGE Risk. 2021 – The copyright of the content of this blog belongs to CGE Risk Management Solutions B.V.}