What is the difference between ISO 13849 and IEC 61508

When it comes to safety standards in industrial automation, two commonly referenced standards are ISO 13849 and IEC 61508. While both of these standards aim at minimizing risks and ensuring the safety of machinery, they have distinct differences in their scope, approach, and application.

The Scope of ISO 13849

ISO 13849 is a standard specifically tailored for safety-related parts of control systems within machinery. It provides guidance on the design, calculation, verification, and validation of safety functions within these control systems. The standard focuses on identifying and reducing risks associated with machine hazards to an acceptable level.

The Scope of IEC 61508

In contrast, IEC 61508 is a wider standard that targets all industries involving functional safety. It provides a framework for the entire safety lifecycle of electrical, electronic, and programmable electronic systems (E/E/PE). Its scope extends beyond machinery and covers diverse applications such as automotive, aerospace, and process industries.

The Approach of ISO 13849

ISO 13849 adopts a performance-based approach. It evaluates the safety of a control system by analyzing the performance of safety-related parts and components, such as sensors, logic devices, and actuators. This standard provides guidelines for determining the required Performance Level (PL) based on the severity of potential injuries, the frequency and duration of exposure to hazards, and the possibility of avoiding or limiting harm.

The Approach of IEC 61508

On the other hand, IEC 61508 follows a goal-based approach. It defines Safety Integrity Levels (SIL) to assess the reliability and dependability of overall safety functions. The SIL levels are determined based on the desired risk reduction measures and the probability of hazardous events occurring. This standard emphasizes the systematic management of safety requirements throughout the entire lifecycle, including specification, design, integration, operation, maintenance, and decommissioning phases.

In conclusion, while both ISO 13849 and IEC 61508 serve the purpose of ensuring safety in industrial settings, they differ in terms of scope and approach. ISO 13849 targets safety-related parts within machinery, employing a performance-based approach to manage risks. On the other hand, IEC 61508 has a broader application range beyond machinery and adopts a goal-based approach for assessing overall system integrity. Understanding these differences is crucial for professionals involved in the design, implementation, and maintenance of safety systems to choose the appropriate standard for their specific needs.