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5.5 System Safety and Reliability

Understand, design and implement safe and reliable machinery and process control and safety systems.

Critical Work Functions

  • 5.5.1 Analyze and determine the need for design changes or additional equipment to improve safety
    • 5.5.2 Determine need for Safety Instrumented Systems (SIS)
      • 5.5.3 Determine the appropriate Safety Integrity Levels (SIL)
        • 5.5.4 Develop safety requirements specification
          • 5.5.5 Design, document, install, validate, periodically check, and maintain the safety equipment and systems
            • 5.5.6 Apply instrumentation procedures in hazardous areas safely
              Technical Content Areas

              • 5.5.7 Alarm management lifecycle
                • Philosophy
                • Identification
                • Rationalization
                • Detailed design
                • Implementation
                • Operation
                • Maintenance
                • Monitoring and assessment
                • Management of change
                • Audit
              • 5.5.8 Reliability
                • Common cause and its impact on reliability
                • Concepts of
                  • Mean Time to Repair (MTTR)
                  • Mean Time to Failure (MTTF)
                  • Mean Time Between Failures (MTBF)
                • Safe and dangerous failure modes
                • Testing intervals and its impact on performance
                • Types of redundancy and how they impact dangerous and safe failure modes
              • 5.5.9 Machine and process guarding
                • Concepts of guarding
                • Design considerations
                • Laws and regulations
                • Protection levels
                • Risk analysis
              • 5.5.10 Safety lifecycle
                • Safety lifecycle
                • Allocation of safety functions to protective layers
                • Determination of safety integrity levels
                • Safety requirements specification
                • Design and engineering issues and system technologies
                • Installation, commissioning, and validation
                • Operations and maintenance
              • 5.5.11 Safety equipment
                • General Purpose Programmable Logic Controllers (PLCs)
                • Safety PLCs
                • Simplex, duplex, triplex, and quad configurations
                • Selection (logic solver, field devices, networks)
                • Diagnostic annunciation
                • Probabilistic modeling
              • 5.5.12 Safe use and application of electrical apparatus
                • Equipment for use where explosive concentrations of gas, vapor, or dust might be present
                • Equipment selection for hazardous areas
              • 5.5.13 Documentation
                • Piping and Instrument Diagrams (P&ID)
              • 5.5.14 Standards
                • ISA 84/IEC 61511 - Safety Instrumented Systems
                • ISA 18 (IEC) 62682) - Alarm Management
                • ISO 13849 - Safety of Machinery
                • IEC 62061 - Functional Safety of Safety-Related Electrical, Electronic, and Programmable Electronic Control systems
                • NFPA 497 - Recommended Practice for the Classification of Flammable Liquids, Gases, or Vapors and of Hazardous (Classified) Locations for Electrical Installations in Chemical Process Areas
                • NFPA 499 - Recommended Practice for the Classification of Combustible Dusts and of Hazardous (Classified) Locations for Electrical Installations in Chemical Process Areas
                • EIC 61508 - Functional Safety of Electrical/Electronic/Programmable Electronic Safety-Related Systems