Emergency Shutdown – Definition and Pronunciation
What is Emergency Shutdown System?
Emergency Shutdown Systems (ESD) is a system, usually independent of the main control system, that is designed to safely shut down an operating system. For example, at ship-shore interface, LNG cargo transfer between ship and shore is accomplished by a series of shore-based articulated loading arms, usually three or four liquid arms and a single vapour arm. The configuration is similar at both the loading and discharge terminals. These arms have flexibility in three directions to allow for relative motion between ship and shore. If this allowable motion is exceeded, alarms sound on the ship and shore. Cargo transfer is automatically stopped, either by the shore pumps shutting down during loading, or the ship’s pumps shutting down during unloading.
Examples of Emergency Shutdown System
If the cargo level in any tank is allowed to reach “extreme high level”, as sensed by the independent sensors (float or radar type), then an emergency shutdown trip is initiated. This will result in closure of the manifold ESD valves and trip the associated equipment.
The Chief Officer heard a noise from the gas blower and, as he investigated it, liquid ethylene erupted from the mast riser. At this point he stopped the blower and closed the tank filling valve. He did not activate the emergency shutdown but instead went to advise the jetty operator verbally.
If an incident occurs during loading or discharging operations the duty officer’s first action must be to stop cargo handling operations using the “Emergency Shutdown System” (ESDS).
Pronunciation of Emergency Shutdown
