Abstract
Safety barrier-based management systems are widely adopted because of the advantages coming from the barrier approach. Different methods are available to implement it and the Bow-tie is one of the most recognized methodology. The Bow-tie method allows the risk analyst to have, in a single shot, the complex picture about the relations linking threats, preventive barriers, top events, mitigative barriers, consequences, and escalation factors. From this perspective, without a proper reference, there are significant possibilities to misuse the method and create confusion about the right role of each component of a Bow-tie diagram. This work intends to support the approach of the guidelines developed by the Center for Chemical Process Safety (CCPS) of the American Institute of Chemical Engineers (AIChE), to drive the analyst in the proper usage of the method, avoiding to misinterpret key elements like the human errors or the barrier failures, and helping in a congruent definition of the elements, thus resulting in a high-quality risk analysis and in a sound barriers management.
