Which system returns an industrial process to a safe state after a predetermined condition was detected?

Which system returns an industrial process to a safe state after a predetermined condition was detected?

• A. Energy (Industries and Sectors)
• B. Safety Instrumented System (SIS)
• C. Facilities (Industries and Sectors)
• D. Healthcare (Industries and Sectors)

Answer: (B)

When a process deviates into an unsafe condition, a dedicated safety control layer steps in to bring the process back to a safe state automatically. This is what a Safety Instrumented System does: it monitors critical process variables, and if a pre-set dangerous condition is detected, it performs the required actions—like stopping equipment or isolating a flow—to return the process to a safe state. This safety system is designed to operate independently from the normal control system to avoid common failures, and it is often rated for specific safety performance levels to ensure reliable response. The other options describe broad sectors (like energy, facilities, or healthcare) rather than a mechanism that actively drives a process to a safe state, so they don’t fit the described function.