What is the difference between IEC 61508 and ISO 26262?

Introduction

The field of industrial automation and automotive technology has witnessed significant advancements in recent years. Safety standards play a crucial role in ensuring the reliable and secure operation of such systems. In this article, we will delve into the differences between two important international safety standards – IEC 61508 and ISO 26262. These standards are widely used for functional safety assurance in different industries.

IEC 61508:

IEC 61508, also known as "Functional Safety of Electrical/Electronic/Programmable Electronic Safety-Related Systems," provides a general framework for managing functional safety throughout the entire lifecycle of systems. It focuses on electrical, electronic, or programmable electronic (E/E/PE) safety-related systems that perform safety functions. The standard encompasses various industries, including process control, power generation, aerospace, and more.

IEC 61508 employs a risk-based approach, emphasizing the need for hazard identification, risk assessment, and mitigation techniques. It defines safety integrity levels (SILs) ranging from SIL 1 to SIL 4, which represent varying degrees of risk reduction. Specific guidelines are provided for each SIL, regarding system design, development, operation, and maintenance.

ISO 26262Automotive Perspective

ISO 26262, titled "Road vehicles – Functional safety," specifically targets the automotive industry. With the increasing complexity of advanced driver assistance systems (ADAS) and autonomous driving technologies, ensuring functional safety has become paramount for automotive manufacturers. ISO 26262 provides a comprehensive set of requirements and processes tailored for the automotive domain.

ISO 26262 adapts the concept of Automotive Safety Integrity Levels (ASILs) to assess the safety significance of potential hazards. The standard identifies various automotive safety goals and defines the corresponding ASILs: ASIL A, ASIL B, ASIL C, and ASIL D. Each ASIL represents a progressively higher level of risk reduction requirements. ISO 26262 guides manufacturers in establishing an effective safety lifecycle, including hazard analysis and risk assessment, functional safety concepts, verification, validation, and more.

Key Differences

While both IEC 61508 and ISO 26262 aim to ensure functional safety, there are some notable differences between them:

Scope: IEC 61508 is applicable to various industries, while ISO 26262 focuses solely on the automotive sector.

Terminology: Each standard possesses its own set of terminologies and definitions specific to their respective domains.

Safety Goals: The concept of Safety Integrity Levels (SILs) is used in IEC 61508, whereas ISO 26262 adopts Automotive Safety Integrity Levels (ASILs).

Documentation Requirements: ISO 26262 imposes more detailed documentation obligations due to the intricacies associated with automotive safety.

Management and Process Requirements: The two standards differ in their treatment of management responsibilities and development processes.

Conclusion

In conclusion, IEC 61508 and ISO 26262 are crucial standards that ensure the functional safety of different systems, ranging from industrial automation to automotive technologies. While IEC 61508 provides a broader framework for various industries, ISO 26262 focuses specifically on the automotive sector. Understanding these standards' key differences is vital for organizations seeking to develop reliable, secure, and safe systems within their respective domains.