An Optimal Design Procedure based on the Safety Integrity Level for Safety-related Systems

• Sung Kyu Kim,
• Yong Soo Kim,

Vol. 12, No. 12, December 30, 2018
10.3837/tiis.2018.12.025, Download Paper (Free):

• Safety-related system
• safety integrity level
• gas detector
• FMEDA
• integer programming

Abstract

Safety-related systems (SRSs) has widely used in shipbuilding and power generation to prevent fatal accidents and to protect life and property. Thus, SRS performance is a high priority. The safety integrity level (SIL) is the relative performance level of an SRS with regard to its ability to operate reliably in a safe manner. In this article, we proposed an optimal design procedure to achieve the targeted SIL of SRSs. In addition, a more efficient failure mode and effects diagnostic analysis (FMEDA) process and optimization model were developed to improve cost efficiency. Based on previous IEC 61508 diagnostic analyses that revealed unnecessary costs associated with excessive reliability, the new approach consists of two phases: (i) SIL evaluation by FMEDA, and (ii) solution optimization for achieving the target SIL with minimal cost using integer-programming models. The proposed procedure meets the required safety level and minimizes system costs. A case study involving a gas-detection SRS was conducted to demonstrate the effectiveness of the new procedure.

Statistics

Cite this article