IEC 61511 is an international standard for the functional safety of safety instrumented systems in the process industry sector. It applies the generic principles of IEC 61508 to end users and integrators, defining a safety lifecycle that spans hazard and risk assessment, allocation of safety functions to protection layers, and verification against target safety integrity levels. It is the dominant reference for emergency shutdown and high-integrity protection systems on process plant.
Overview
- IEC 61511 specifies requirements for the specification, design, installation, operation and maintenance of safety instrumented systems used to achieve or maintain a safe state of a process.
- It implements the framework of IEC 61508 for end users and integrators in the process industries, including oil and gas, chemicals, and power generation.
- The standard organises work around a safety lifecycle, from hazard and risk assessment through verification, validation and management of functional safety.
Key aspects
- Safety lifecycle phases spanning analysis, realisation and operation.
- Allocation of safety functions to protection layers with target risk reduction.
- Quantification of safety integrity via probability of failure on demand.
- Competency, audit and management-of-change requirements.
Applications
- Emergency shutdown systems on hydrocarbon process plant.
- Burner management and high-integrity pressure protection systems.
- Safety functions implemented in SCADA and distributed Control System architectures.