Background: The complexity of modern sociotechnical systems has created new challenges for safety, so that traditional approaches are not able to cope with them. Resilience engineering (RE) is a good alternative to traditional approaches for safety management, however resilience is still a difficult concept to measure, and indicators such as buffering capacity, flexibility, and so on, which are thought to contribute to it, are undeveloped.
Objectives: This study aimed at expanding buffering capacity as one of the main indicators in order to facilitate measurement of resilience of a system.
Materials and Methods: We used the Delphi method in order to identify indicators, and data related to all the indicators were gathered by observation and interview. In this line, 32 of the experienced operators with at least 15 years of operational record were selected for semi-structured interviews. Gathered data was processed by the principal component analysis technique. The results were processed by the Minitab 15 software.
Results: In this study, 29 factors affecting this indicator were determined using the Delphi method; the scores of all factors were less than the scores of the best practice. On the other hand, the state of this indicator was poor in plant included in the study.
Conclusions: This was the first study that focused on expanding resilience indicators, and presents a new framework to simplify assessment of resilience and safety of a complex system.