SIGMA Emergency Shutdown System (ESD) is designed to minimize the consequences of emergency situations, related to typically uncontrolled flooding, escape of hydrocarbons, or outbreak of fire in hydrocarbon carrying areas or areas which may otherwise be hazardous.
Traditionally risk analyses has concluded that the Emergency Shutdown system is in need of a high Safety Integrity Level, typically SIL 2 or 3. Basically the system consist of field-mounted sensors, valves and trip relays, system logic for processing of incoming signals, alarm and HMI units. The system is able to process input signals and activating outputs in accordance with the Cause & Effect charts defined for the installation.
Typical Actions from an Emergency Shutdown System
- Shutdown of part systems and equipment
- Isolate hydrocarbon inventories
- Isolate electrical equipment
- Prevent escalation of events
- Stop hydrocarbon flow
- Depressurize / Blow down
- Emergency ventilation control
- Close watertight doors and fire doors