The Emergency Shutdown (ESD) System is defined as a system which immediately terminates all production activity and other systems not essential for platform emergency operation. The ESD-systems should be independent from and in addition to other systems and generally based on a "fail-safe" principle.
Experience with ESD-systems is fairly good. However, further improvements could be done on sensors and valves and on man-machine interactions.
Reliability of computer systems to be closely monitored; e.g. for internal faults.
The principal aims and objectives of an ESD system are to reduce the consequences of an accident or a hazard in order to ensure the following:
The protection of personnel.
The protection of plant and equipment and the maintenance of safe operation compatible with production requirements.
The minimization of pollution of the environment where this may be applicable.
Emergency shutdown (ESD) system is defined as a system which immediately terminates all production activity on a platform including closing of pipeline shutdown valves and shutting down all equipment and systems not pipeline shutdown valves and shutting down all equipment and systems not essential for platform emergency operation. In addition, some safety actions are automatically initiated, e.g. start of fire pumps and emergency generator.
During normal production, the process- and utility systems are controlled by the control system onboard the installation. All process parameters such as temperature, pressure, level etc, are then kept within well defined limits. In case of set point adjustments, the control system transfers and stabilizes the process parameters within the new limits.
Incidents where the process parameter limits are exceeded due to failure of the control system or minor local equipment failures, will normally be taken safely care of by the manual intervention from control room operators acting upon alarms or by the process shutdown (PSD) system.