Applying and Evaluating Architectural IEC 61508 Safety Patterns

Abstract—An important step for developing a safety-critical system is the design of its architecture. The IEC 61508 standard provides a set of architectures (1oo2, 2oo3, ...) on a high level. It is left up to the system architect to refine these architectures and to come up with a set of methods which achieve the safety goals of the system. A pool of these methods is listed in part 7 of the IEC 61508 standard. However, especially for novel safety architects choosing appropriate methods and arguing for system safety through the application of these methods is rather difficult.
In this paper we present the application of safety patterns in order to address this problem. Our safety patterns connect IEC 61508 methods to the high level architecture to provide a way to reason about a system’s safety. We apply a safety pattern to two real case studies and we evaluate the pattern by comparing the IEC 61508 methods suggested by the pattern to the IEC 61508 methods actually chosen by the real system architectures.

Index Terms—Design patterns, functional safety, IEC 61508.

Christopher Preschern, Nermin Kajtazovic, and Christian Kreiner are with the Institute for Technical Informatics, Graz University of Technology, Austria (e-mail: christopher.preschern@tugraz.at, nermin.kajtazovic@tugraz.at, christian.kreiner@tugraz.at).

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Cite: Christopher Preschern, Nermin Kajtazovic, and Christian Kreiner, "Applying and Evaluating Architectural IEC 61508 Safety Patterns," Lecture Notes on Software Engineering vol. 2, no. 1, pp. 1-5, 2014.