Functional safety for ITER project instrumentation and control...
Functional safety for ITER project instrumentation and control systems
At industrial sites, the causes and consequences of hazards go well beyond technological aspects: they must be considered from financial, property, human and environmental perspectives. The physical integrity of an industrial site is characterised by the compliance with industrial processes and the preservation of product integrity.
Functional safety, as introduced in standard IEC 61508, covers Automated Safety Systems and Safety Instrumented Systems used for risk prevention and the protection of humans, the environment, and the industrial facilities themselves. These systems respond to stimuli to maintain the safety of assemblies or to place them in a safe configuration, acting as interlocking mechanisms. The risk reduction level to be obtained is then quantified in a SIL (Safety Integrity Level).
The Assystem approach to functional safety covers all phases from the identification and characterisation of risks through to Maintenance in Operational Condition (MOC) of critical systems, and also includes their specification, design and turnkey integration.
Assystem has developed significant know-how organising maintenance teams (MOC/Third-party Application Maintenance) on-site for critical systems. In terms of the systems covered by standard IEC 61511 for example, these work teams intervene directly to ensure high levels of safety performance for these systems (safety integrity) and their monitoring.
There are many criteria that influence the nominal operations of a critical system (initial design choices, documentation, training of operational and maintenance personnel, obsolescence management, execution of preventive maintenance, physical and cyber security for the system itself and the associated utilities etc.).
Industrial information and control systems
"Global security" approach
Identification and characterisation of hazards and risks (Preliminary Risk Analysis), determination of risk reduction levels (SIL).
Functional specification, definition of operation and maintenance modes, drafting of specifications etc.
Respect of organisational restrictions dictated by standards and targeted safety performances (safety cycle), best-fit technological solutions, anticipation of operational and maintenance limitations etc.
Evaluation of real SILs (analysis of conformity of architectures, component choices, management strategies for common modes, resilience to failure), analysis of organisational measures for operation and maintenance, implementation of dedicated monitoring functions etc.
Preventive maintenance and periodic testing, diagnostics and corrective maintenance, obsolescence management, hardware/software configuration management, organisation and upkeep of skills, change management (regression tests, impact studies, documentation updates etc.).