What is the difference between IEC 61508 and ISO 26262?

When it comes to safety-critical systems, two key standards that often come up are IEC 61508 and ISO 26262. These international standards have been widely adopted in various industries to ensure the functional safety of electronic systems. While they have similar goals, there are some fundamental differences between the two. In this article, we will explore the key aspects and variances in the application of IEC 61508 and ISO 26262.

IEC 61508: Functional Safety of Electrical/Electronic/Programmable Electronic Safety-related Systems

IEC 61508 is a globally recognized standard that addresses the overall system lifecycle requirements for functional safety. It covers a broad range of industries, including process control, power generation, rail transportation, and more. The standard provides a framework for managing risks associated with safety-critical systems throughout their operational life.

One of the primary objectives of IEC 61508 is to identify and mitigate potential hazards by applying systematic analysis techniques, such as Failure Mode and Effects Analysis (FMEA) and Fault Tree Analysis (FTA). It emphasizes the concept of Safety Integrity Levels (SILs), which define the necessary risk reduction measures based on the severity of potential harm and the likelihood of occurrence.

ISO 26262: Road Vehicles - Functional Safety

While IEC 61508 has a broader scope, ISO 26262 specifically focuses on functional safety in road vehicles. The automotive industry has its unique challenges, particularly concerning the complex interconnected electronic systems found in modern vehicles. ISO 26262 offers specific guidelines and requirements for achieving safety in automotive electrical and electronic systems.

An essential aspect of ISO 26262 is the Automotive Safety Integrity Level (ASIL), which classifies the safety requirements based on the potential impact of a failure on the driver, passengers, and other road users. It encompasses the entire vehicle development process, including system requirements engineering, hardware and software development, integration, verification, and validation.

Differences in application

While both standards address functional safety, IEC 61508 is general and can apply to various industries, while ISO 26262 is specific to the automotive domain.

IEC 61508 provides a framework that allows industry-specific standards, such as ISO 26262, to be derived from it. The automotive sector, therefore, often relies on both standards for comprehensive functional safety processes.

ISO 26262 places a more significant emphasis on the management of functional safety throughout the product development lifecycle. It requires the establishment of a safety culture within the organization, with clear responsibilities and processes for assessing and mitigating risks.

Conclusion

Both IEC 61508 and ISO 26262 play crucial roles in ensuring the functional safety of electronic systems, although their focus and applications differ. While IEC 61508 provides a broader framework for functional safety across various industries, ISO 26262 specifically caters to the complexities of safety in road vehicles. By adhering to these standards, organizations can enhance the reliability and safety of their products, minimizing the risks associated with safety-critical systems.