How many parts is the IEC 61508 standard divided into?

The IEC 61508 standard is a comprehensive guideline for determining the functional safety of electrical, electronic, and programmable electronic systems. It provides a framework for the development and assessment of these systems within various industries, including automotive, nuclear, and industrial automation. To ensure effective implementation, the standard is divided into several parts, each focusing on specific aspects of functional safety.

Part 1: General requirements

The first part of the IEC 61508 standard sets out the general requirements necessary for achieving functional safety. It covers topics such as system definition, management of functional safety, and the establishment of safety integrity levels (SILs). SILs provide a quantitative measure of risk reduction and serve as benchmarks for system design and validation. Additionally, this part outlines the importance of documentation, verification, and validation throughout the system's lifecycle.

Part 2: Requirements for electrical/ electronic/ programmable electronic safety-related systems

Part 2 of the IEC 61508 standard focuses on the specific requirements for ensuring the functional safety of electrical, electronic, and programmable electronic safety-related systems (E/E/PES). It emphasizes the necessity of systematic and iterative analysis, risk assessment, and mitigation during the development and operation phases. This section also highlights the importance of proper maintenance, modification, and decommissioning of E/E/PES to prevent any potentially hazardous situations.

Part 3: Software requirements

Part 3 of the IEC 61508 standard is dedicated to providing guidelines for software development within safety-related systems. It emphasizes the need for a systematic approach to software engineering, including requirements specification, design, coding, testing, and maintenance. This section emphasizes the importance of using rigorous development methods, such as formal analysis and verification, to minimize software faults that could lead to functional safety failures.