Lifecycle costs of safety instrumented systems in process industries: a systematic literature review

A safety instrumented system (SIS) is an automated system designed to detect and mitigate potential risk of hazardous conditions in industrial processes by taking actions to prevent or mitigate incidents. It is essential because it helps protect people, equipment, and the environment by reducing the risk of accidents in hazardous operations, such as in chemical plants, oil refineries, or power stations. While the primary objective of SIS design is safety, economic considerations, particularly lifecycle cost, play a pivotal role in decision-making during the design phase. Although research efforts exist to incorporate lifecycle cost with safety, the literature is fragmented and lacks a comprehensive lifecycle cost framework. Therefore, a systematic literature review is conducted to uncover safety instrumented systems’ lifecycle cost elements and the decision variables that impact them. The review results lead to a comprehensive and structured cost calculation framework to assess SIS designed to protect a process unit economically. Finally, this study provides perspectives on potential research directions relevant to SIS lifecycle cost, including the impact of systematic failures, cybersecurity integration, the relative weighting of different cost elements, inclusion of risk costs, and various SIS application types.