Emergency Shutdown (ESD) System systems serve to prevent escalation of emergencies, such as fires, explosions, and leaks.
- ESD systems protect worker safety by shutting down processes & isolating areas in the event of a harmful condition.
- Environmental protection involves controlling spills or leaks & shutting down processes.
Components of an ESD System
ESD Valve
Actuated Valves: These are key components of the ESD system that close automatically when a shutdown signal is received.
Pressure Relief Valves (PRVs): Automatically relieve pressure in vessels (or) pipelines to avoid overpressure situations.
Sensors & Detectors
Gas Detectors: Determine the presence of flammable or dangerous gases & initiate shutdown procedures.
Fire Detectors: Detect fires using smoke, heat, (or) flame detection, and activate the ESD.
Pressure Sensors: Monitor pressure levels in pipelines & vessels, and activate the ESD if they exceed safe limits.
Temperature Sensors: Monitor temperature in important locations to identify overheating.
Logic Solver
Programmable Logic Controllers (PLCs): These are the ESD system’s brains, processing data from sensors and detectors to determine when to trigger shutdowns.
Safety Instrumented Systems (SIS): These systems have PLCs that are designed to meet certain safety requirements.
Control Panel
ESD Control Panels: These centralised equipment allow operators to manually activate or reset the ESD system, check system status, and run diagnostics.
Human-Machine Interfaces (HMI): Give operators a visual interface to engage with the ESD system by displaying real-time data and alarms.
Emergency Shutdown Buttons (ESB)
Manual ESD Stations: These stations are strategically located around the site and allow personnel to manually switch on the ESD system in the event of an emergency.
Alarms & Indicators
Audible & visual alarms: Alert personnel to an emergency & the activation of the ESD system, requiring rapid evacuation or other safety actions.
Shutdown Procedures
Sequential Shutdown: The system is programmed to shut down the facility in a certain order to prevent creating additional dangers. To prevent overpressure, stop down pumps before closing valves.
Partial (or) Full Shutdown: Depending upon the severity of the issue, the ESD system can be set to turn off only the affected regions (partial shutdown) (or) the entire facility (full shutdown).
Types of ESD Levels
Level 1 (Full Plant Shutdown)
Enables all safety measures and isolates the whole facility.
Level 2 (Process Isolation)
Isolates specific process units (or) sections of the plant while leaving others operating.
Level 3 (Component Isolation)
Isolates certain components, such as a single pipeline (or) vessel, without disrupting the overall process.