Safety Instrumented Systems (ISA-84 / IEC 61511)

Safety Instrumented Systems – Design, Analysis & Justification

This course focuses on the engineering requirements for the specification, design, analysis, and justification of safety instrumented systems for the process industries. Students will learn how to determine safety integrity levels and evaluate whether proposed or existing systems meet the performance and documentation requirements defined in the ISA84 standard.

You will be able to:

• Differentiate between process control and safety control
• Understand and implement the ISA 84 standard
• Evaluate process risk levels
• Determine Safety Integrity Levels (SILs) using a variety of techniques
• Analyze the performance of different logic system technologies
• Analyze the performance of various sensor, logic, and final element configurations, as well as the impact of diagnostics, test intervals, common cause, system size, and more
• Determine optimum system test intervals
• Specify and select safety instrumented systems
• Satisfy the documentation requirements for process safety management, regulations, and industry standards

You will cover:

• Introduction: Danger of Overconfidence and Complacency | Lessons Learned From Past Accidents
• Guidelines and Standards: ANSI/ISA | AIChE | IEC | HSE | OSHA
• General SIS Design Considerations: Design Life Cycle | Separation of Control and Safety | Independent Safety Layers
• Hazard and Risk Assessment: Hazard Identification | Risk Assessment | Determining Safety Integrity Levels | Layer of Protection Analysis
• Failure Rates & Modes: Safe vs. Dangerous | Failure Mode vs. Technology | Failure Rates | Test Intervals
• System Technologies: Pneumatic | Relay | Microprocessor | Field Devices | Certification | Prior Use
• Operations and Maintenance: Installation | Bypassing | Testing | Management of Change | Decommissioning
• Class Examples: Putting it all together

Classroom/Laboratory Exercises:

• Calculate device failure rates and determine safe vs. dangerous performance
• Model system performance for relay and software based logic systems
• Model the impact of field devices, automatic diagnostics, manual test intervals, common cause, and more
• Determine the SIL (safety integrity level) of a sample processes and design an SIS to meet the performance requirements

Length
3 days