Towards Dynamic Safety Control Structures in STAMP to Manage Safety-Critical Industrial Establishments

The Directive 2012/18/EU (also known as Seveso III Directive) is at the core of safety management in industrial establishments dealing with dangerous substances. The establishments falling under the Seveso III Directive – and all other entities involved – can be recognized as parts of a Socio-Technical System (STS), due to the presence of tightly interacting technical, social, and organizational elements. This paper relies on the System-Theoretic Accident Model and Processes (STAMP) principles to let critical interactions among system elements emerge. The approach starts with the construction of a dedicated Safety Control Structure (SCS) for the processes described in the Seveso III Directive. However, since the interactions included are highly variable because of their interplays, and because of time and causal dependencies, the traditional SCS perspective limits the analysts' capabilities. In traditional STAMP, such interaction is implicit, requiring ad-hoc solutions to be interpreted. This paper discusses the benefit of adding a dynamic dimension to the SCS to properly consider temporal and causal developments, as well as dependencies within the various processes. Such dynamicity is related to the definition of triggers being able to activate (or deactivate) the mutual dependencies among agents, based on their correlation and their presence in specific circumstances. Results show how such dynamic dimension is a core feature for operationalizing any SCS in real case scenarios.

Keywords: Systems theory, Major accident hazard, Risk management, Industrial plants, Operations management.