ISO26262-1:2018-FSM
Functional safety is the part of a system’s safety that relies on an automated control system to detect and respond to faults, preventing hazardous situations and reducing risk. It applies to systems where malfunctions could cause physical injury or damage, such as in automotive safety features like airbags or industrial robotics. Key aspects include reducing risks associated with electrical/electronic malfunctions, establishing standards like the base IEC 61508 or industry-specific variations (e.g., ISO 26262), and implementing measures to ensure reliability, diagnostics, and quality management.
What functional safety is
- Risk reduction: It is a method for ensuring systems operate safely by minimizing risks associated with electronic and electrical malfunctions.
- Automated control: It focuses on the parts of a system that perform automated safety functions, including sensors, logic, and actuators.
- Safe failure: The goal is to design systems so that if they do fail, they fail in a safe mode, rather than causing harm.
How it works
- Risk assessment: A risk assessment is performed to determine the required level of safety. This often results in a Safety Integrity Level (SIL), with SIL 1 being the lowest and SIL 4 being the highest risk.
- Standards: Functional safety is guided by standards. The foundational standard is IEC 61508, but many industries have specific standards that are based on it, such as ISO 26262 for the automotive sector.
- Systematic and random failures: Standards help to avoid “systematic failures” (caused by design errors) and control “random hardware failures” (which occur unpredictably).
- Hardware and software: Functional safety can apply to both the hardware (like brakes) and the software components of a system
Functional safety is a critical part of the overall safety of equipment or a system that relies on automatic protection mechanisms to respond correctly to inputs or failures in a predictable manner, thereby minimizing the risk of harm to people, property, and the environment. This is achieved by designing and implementing safety functions into a system, which are intended to detect potentially dangerous conditions and take appropriate action to prevent accidents or mitigate their effects
Key Principles
- Risk Reduction: The primary goal is to reduce risk to a tolerable level. This involves identifying potential hazards through analysis methods like Hazard and Risk Assessment (HARA) or Failure Modes and Effects Analysis (FMEA), and determining the required performance level of the safety functions.
- Active Protection: Functional safety systems are active, meaning they react to predefined triggers to change the system to a safe state (e.g., a sensor in a machine detecting a person and stopping the robot).
- Predictable Response: The system must have predictable responses to failures, including human errors, hardware failures, and operational stress.
- Lifecycle Management: Functional safety involves a systematic approach that covers the entire product lifecycle, from initial concept and design to implementation, operation, maintenance, and eventual decommissioning