A safety-instrumented-system is an instrumented system consisting of sensors, a logic solver, and final elements, designed to execute one or more safety functions to put or keep a process in a safe state when specified predetermined conditions are violated. Each safety function is assigned a safety integrity level (SIL 1–4) based on required risk reduction. The system is designed, implemented, operated, and maintained according to a systematic and managed lifecycle per IEC 61508/61511. [formal: systema instrumentatum securitatis | substrate: behavior | horizon: a life | explicit: yes | epoch: 0.98]
Accepted ontology entry
safety-instrumented-system
A safety-instrumented-system is an instrumented system consisting of sensors, a logic solver, and final elements, designed to execute one or more safety functions to put or keep a process in a safe state when specified predetermined condit…
Definition
Why it is in scope
A human-made instrumented system (including sensors, logic solvers, and final elements) designed to automatically put an industrial process into a predetermined safe state when predefined conditions are violated. Developed under IEC 61508/61511 standards as part of the layered protection approach in process safety engineering.
Names and aliases
- safety-instrumented-systemen · CANONICAL
Relations from this entry
- cms8olo5701ld73fkxedp404qSERVES →
An SIS is built and maintained for the sake of process-safety. Its designed purpose is to prevent and mitigate process hazards by putting the process into a safe state when dangerous conditions are detected.
- cms8tngna024w73fk1u4fxsbmSERVES →
safety-instrumented-system SERVES safety-requirement: the safety-instrumented system (e.g. emergency shutdown system, fire detection system) is designed and maintained specifically to fulfill safety requirements. Its purpose is to achieve and maintain the performance levels specified by those requirements. For whose sake does the system operate? For the safety requirements it exists to satisfy.
Relations to this entry
- cms8v7kwr02b273fk90u7duiv← SERVES
Safety-interlocks are mechanical or electronic devices designed to prevent equipment operation until safe conditions are confirmed. Their designed purpose is to serve safety-instrumented-systems by providing hard-wired fail-safes that enforce safe states independently of control system logic. Law 8d: for whose sake? The interlock serves the SIS.
Record identity
- Created
- Jul 31, 2026, 9:18 AM UTC
- Content hash
- 72c8af37270d5157060c4316e1486ef963cc0732bb01604ac2270cd9edfd8b19