Risk Analysis Methods (Consequences)

The Bow-Tie method can be considered to be a combination of earlier developed fault tree analysis (FTA) and event tree analysis (ETA) methods. A significant milestone in the history of Bow-Tie was the catastrophic incident on the Piper Alpha platform in 1988, which shook the oil and gas industry. In the early 1990s, the Royal Dutch Shell adopted the BowTie method as part of its methodological toolbox for managing risks. Nowadays, the Bow-Tie method is also used for risk management related to different transport modes such as maritime and aviation.

The Cause-Consequence Diagram is developed from a certain initiating top event, i.e. an event that initiates a specific operational sequence or an event which activates certain safety systems. The Cause-Consequence Diagram consists of two reliability analysis methods previously elaborated, the FTA and ETA methods.

Checklists are a very simple way to identify risks. As a rule, checklists consist of standardized questionnaires that help to systematically record risks. They can contain open or closed questions, whereby closed questions are better suited for the identification of risk potentials, since the evaluation of the answers is simpler and thus leads faster to concrete results. The questions mostly arise with creative techniques. Workshops, brainstorming, etc. are most commonly used in the creation process.

Event Tree Analysis (ETA) is a method that examines the consequences of a particular event. Starting from an initial event, the tree is divided into two branches, whereby the upper one represents a positive and the lower one a negative development (event trees are usually drawn from left to right). Repeated branching of the tree shows possible effects of an initial event on a system. The aim of ETA is the identification of possible damage events. 

The Failure Mode and Effects Analysis is a cross-industry established method to identify and eliminate potential failures, problems, errors and risks of a system, design or process before adverse consequences reach the internal/external customers. The basic idea of the FMEA is thus the preventive risk identification and error prevention instead of a subsequent correction.