Functional Safety
- Tim Williams
Overview
Functional safety is, simply put, “Protecting a user from technology”. It also protects technology from users. More technically however, the definition of Functional Safety is, “Systems that lead to the freedom from unacceptable risk of injury or damage to the health of people by the proper implementation of one or more automatic protection functions (often called safety functions). A safety system consists of one or more safety functions.” – TÜV SÜD
Functional safety refers to the concept of ensuring that a system, process, or product operates in a safe manner, particularly when it comes to preventing or mitigating hazards that could lead to harm, injury, or damage. It involves designing, implementing, and maintaining safety measures to ensure that a system behaves in a way that reduces or eliminates risks associated with its operation.
Functional safety is especially important in industries where human safety is a primary concern, such as automotive, aerospace, manufacturing, oil and gas, medical devices, and industrial automation. The goal of functional safety is to minimize the likelihood and severity of accidents and incidents caused by system failures, errors, or malfunctions.
Key aspects of functional safety include:
Hazard Analysis: Identifying potential hazards that could arise from system failures or malfunctions. This involves a thorough assessment of the risks associated with the system's operation.
Risk Assessment: Evaluating the severity and likelihood of each identified hazard and determining the level of risk it poses to personnel, the environment, equipment, and other assets.
Safety Requirements: Defining safety requirements that the system must meet to prevent or mitigate hazards. These requirements guide the design, development, and operation of the system.
Safety Integrity Level (SIL): Assigning a Safety Integrity Level to each safety function based on the risk assessment. SIL is a measure of the reliability and performance of safety systems, with higher SIL values indicating a higher level of safety.
Safety Standards: Adhering to industry-specific safety standards and guidelines that provide best practices and requirements for ensuring functional safety. Examples include IEC 61508 (general standard) and ISO 26262 (automotive).
Safety Systems and Devices: Implementing safety mechanisms and devices, such as emergency stop buttons, safety interlocks, redundant control systems, and fail-safe mechanisms, to detect and prevent hazardous situations.
Safety Functions: Designing safety functions that monitor critical parameters, detect deviations from safe conditions, and initiate appropriate actions to prevent accidents or harm.
Testing and Verification: Rigorous testing, validation, and verification processes to ensure that safety measures and functions operate as intended and can effectively mitigate risks.
Maintenance and Documentation: Establishing procedures for maintaining and monitoring the functional safety over the entire lifecycle of the system. Keeping detailed documentation of safety-related decisions, designs, and actions.
Training and Awareness: Ensuring that personnel working with or around the system are properly trained and aware of safety protocols and procedures.
Functional safety is an ongoing process that spans the entire lifecycle of a system, from design and development to operation and decommissioning. It requires a multidisciplinary approach involving engineers, designers, operators, and safety experts to ensure that safety is integrated into every aspect of a system's functionality.
Further Reading
TUV Functional Safety Overview
Functional Safety -- Wikipedia entry
Resources
Allen-Bradley Functional Safety Documents