The construction and accessories of Shutdown Valve (SDV) and Emergency Shutdown Valve (ESDV) are similar. What is the basis to distinguish their name?
Their name is distinguished only from their services. Shutdown Valve referred to actuated valve which is closed during partial or total process shutdown of system to which the valve protects. Emergency Shutdown Valve is actuated valve which is closed when triggered by signal from ESD level signal during emergency condition occurs.
Emergency Shutdown Valves are commonly located in incoming line and outgoing line of the plant or platform.
Please note that some projects do not use term “ESDV” for tag numbering, instead Term “SDV” is used for shutdown valve disregard their services. In this case, shutdown logic diagram would indicate which actuated valve acts as Emergency Shutdown Valve.