Solenoid actuator / solenoid valve (SOV)

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

Drawn as

A square box containing "S" on the stem of a small valve, or a small S box on the air supply to a larger actuator.

Meaning

Solenoid. On its own small valve it is a solenoid valve; on the air line of an ESDV actuator it is the SOV that vents the actuator to trip the valve. An accessory, not modelled separately; the main valve is what becomes esd-valve or blowdown-valve.

Variants

Manual-reset solenoids add "R" in the box or beside it
De-energise-to-trip vs energise-to-trip is written on the C&E, not the symbol