What are the common safety interlocks?

Common safety interlocks are designed to automatically shut down or take a process to a safe state when certain hazardous conditions are detected. They act as a critical layer of protection to prevent accidents and protect personnel, equipment, and the environment. Examples include: 1. High-pressure interlock: Shuts down a pump or closes a valve if the pressure in a vessel or pipeline exceeds a safe limit. 2. High-temperature interlock: Shuts down a heater or reactor if the temperature exceeds a safe limit. 3. Low-level interlock: Shuts down a pump if the liquid level in a tank drops below a safe minimum. 4. High-level interlock: Shuts down an inlet valve if the liquid level in a tank exceeds a safe maximum. 5. Flameout interlock: Shuts off the fuel supply to a burner if the flame is extinguished. 6. Emergency shutdown (ESD): A system that initiates a complete or partial shutdown of a process in response to a major emergency, such as a fire, explosion, or large release of hazardous materials. 7. Safety Instrumented System (SIS): A dedicated system that responds to hazardous conditions independently of the basic process control system (BPCS), often including interlocks with specific safety integrity levels (SIL). These interlocks are designed with redundancy and fail-safe mechanisms to ensure reliable operation.