Emergency shutdown valve (ESDV)

ISA 5.1-2009/2022 (final control element actuators) / PIP PIC001 / API 6D

Drawn as

A ball (or gate) valve with a spring-return cylinder on the stem, a small "S" box on its air supply, and "FC" written under the body.

Meaning

Shutdown valve tripped by the ESD/PSD system. It fails closed: the spring shuts it when the SOV vents the air. Inlet, outlet, riser and fuel-gas isolations. Becomes esd-valve.

Variants

Some companies tag it SDV or XV; riser valves are often ESDV-R…
The body may be drawn filled when normally closed
Partial-stroke test devices and limit switches (ZSO/ZSC) are often drawn beside it