Functional Safety: Ensuring Safety of Industrial Systems and Processes
Author : Leena Shedmake | Published On : 19 Mar 2024
Introduction to Functional Safety
Functional safety is the aspect of overall safety related to the correct functioning of systems and components. It involves identifying potential failure modes and mitigating their effects through the implementation of safety requirements, design concepts, and reliability/quality assurance measures. The goal of functional safety is to prevent unsafe behavior and ensure systems function as intended even when external influences or internal failures occur.
Functional Safety Standards
International standards like IEC 61508 and ISO 26262 provide guidance on implementing functional safety in electrical, electronic and programmable electronic systems used in industrial applications. These standards lay out a risk-based approach and safety life-cycle to ensure hazards are identified and safety requirements are systematically derived, designed, verified, validated and operated safely. Key aspects covered include safety management, concept phase, overall safety requirements, safety validation, hazard and risk analysis, safety integrity levels and safety unit verification. Compliance to functional safety standards helps improve product safety, quality and legal defensibility.
Hazard and Risk Analysis
Undertaking a thorough hazard and risk analysis is crucial in Functional Safety . This involves systematically identifying all potential hazards, analyzing associated accident scenarios and their causes, estimating likelihood and severity of consequences. Risk assessment techniques like failure mode and effects analysis (FMEA), hazard and operability study (HAZOP) help in this process. Identifying hazards early allows incorporating necessary design changes to mitigate risks cost-effectively. Safety requirements are then specified to bring risks to acceptable levels defined by safety integrity levels (SIL). Traceability must be maintained between hazards, requirements and validation methods.
Design and Development for Functional Safety
Once safety requirements have been defined, the next phase involves designing systems with sufficient safety measures. Design concepts must incorporate fault tolerance, fail-safety, self-monitoring and diagnostic features. Hardware and software architectural constraints are imposed depending on SIL. Modularization, independence of safety functions, self-testing and diverse monitoring help achieve safety integrity targets. Validation of safety properties through techniques like hazard simulation, fault injection testing increases design robustness. Rigorous product development processes like ISO 26262 ASIL D further improve functional safety.
Functional Safety Validation and Assessment
Thorough validation is necessary to ensure safety functionality and integrity requirements are correctly implemented in the final product. This involves auditing safety cases, inspection of verification plans and coverage metrics, testing of fault tolerant properties, sampling embedded code reviews. Independent assessment by certification bodies offers additional assurance. Field safety monitoring and product improvement processes help address vulnerabilities revealed after deployment. Regular safety reviews evaluate if safety goals are still being met and additional risks have been accounted for from design changes or operating experience. Continuous evaluation against functional safety standards is important.
Functional Safety in Manufacturing Systems
Manufacturing industries dealing with heavy machinery, robotic processes and discrete part automation rely heavily on functional safety principles to ensure employee and equipment safety. Industrial control systems, safety controllers, emergency stop circuits, light curtains, safety sensors play important functional safety roles in production lines, assembly systems, AGVs, AGVs,robot arms and more. Application of functional safety engineering best practices helps achieve safety integrity targets, manage change control and maintain compliant, low-risk operations critical for worker protection and business continuity. Adherence to standards greatly aids safety certification for global market access.
Functional Safety in Automotive Systems
The automotive industry follows stringent ISO 26262 functional safety standard for road vehicles. Braking, steering, suspension, airbags all involve safety-critical functions. Identification and risk assessment of accident scenarios helps define automotive safety integrity levels for electronic/electrical systems based on severity and exposure. Techniques like automotive safety analysis help achieve ASIL safety goals cost-effectively in EB brakes, driver assistance, infotainment and autonomous driving applications. Rigorous systems engineering, software validation and product liability management are hallmarks of automotive functional safety best practices for passenger security and OEM reputation.
Applying Functional Safety in Other Domains
Other industries like aviation, medical devices, rail also rely on functional safety principles adapted from process industry standards. Aviation systems dealing with engines, flight controls require DO-254 design assurance levels to prevent hazards. Medical devices involve risks of patient injuries from infusion pumps, ICDs - necessitating IEC 62304 compliance. Rail signaling, train control safety integrity levels are governed by CENELEC 50128, 50129 standards. Functional safety also extends to building automation, renewable energy, military systems to ensure equipment and operational safety. Robust hazard analysis customized to each domain helps systematically identify safety measures, validate safe operation through product lifecycle.
Functional Safety Training and Certification
Functional safety training for engineers helps them understand safety lifecycle processes, standards and apply them correctly to systems design. ISEB, TUV SUD, Exida offer internationally recognized functional safety certification to validate practitioner competence. Certified Functional Safety Expert (CFSE) accreditation involves written exams on IEC 61508, ISO 26262 covering functional safety management, hazards and risk assessment, safety requirements specification, validation techniques. Hands-on work experience further strengthens skills to lead functional safety projects, perform system safety engineering reviews and safety case audits. Certified professionals play an important role in driving safety excellence within organizations.
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