A study of incidents involving programmable electronic safety-related systems

Abstract This paper presents a study of 21 incidents 1 in small manufacturing enterprises involving electrical/electronic/programmable electronic (E/E/PE) safety-related systems, originally investigated by the Health and Safety Laboratory (HSL). The aim of this study is to highlight the causes of these incidents and suggest common solutions to those causes. A fault schema suitable for the classification of incidents of this nature is proposed. For each incident, identified faults are labelled according to the fault schema and are also denoted as primary, secondary or incidental. Examples of particular causes are given. The prominent faults are further discussed with the goal of highlighting the categories of faults most prominent in E/E/PE safety-related systems. This pinpoints the areas where future work on incident prevention should focus. Finally, mitigation techniques which could form part of an E/E/PE safety-related system development methodology suitable for small manufacturing enterprises are suggested.