What is the difference between a gate and a globe valve symbol?

Both use the bow-tie body. A globe valve adds a filled circle at the center to show the plug/seat; a plain bow-tie is the generic gate / on-off valve. Globe valves throttle; gate valves isolate.

What do FC, FO and FL mean on a valve?

They are fail-safe positions: FC = fail closed, FO = fail open, FL = fail last/locked. They tell you where the valve goes when its actuator loses air or power.

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P&ID valve symbols

Q: What does a control valve symbol look like?

A control valve is a valve body (usually a globe-style bow-tie) topped by an actuator symbol — a diaphragm dome, a piston, a motor M or a solenoid. It is tagged with a control function such as FCV, PCV or TCV.

Reference guide · ISA-5.1 · ~9 min

Valves are the most varied symbol family on a P&ID. The trick to reading them: the body tells you the valve type, and what sits on top tells you the actuator. Here are the common ones, drawn in clean ISA style — with how to get each as PNG/SVG.

The common valve bodies

All share the classic two-triangle "bow-tie" body. Small additions distinguish the type:

Gate / on-off

Generic bow-tie. Isolation — fully open or shut.

Globe

Filled center plug. Throttles / regulates flow.

Ball

Open circle (the ball). Quick quarter-turn shut-off.

Butterfly

Diagonal disc line. Compact, good for large bore.

Check

Arrow into a seat. Non-return — flow one way only.

Control valve

Body + actuator on a stem. Tagged FCV / PCV / TCV.

Other bodies you'll meet: needle (fine throttling), 3-way (a third triangle for diverting/mixing), diaphragm and plug valves.

Actuators — what sits on top

The actuator symbol on the stem tells you how the valve is driven:

Manual — a hand-wheel (a "T" or a small bar) on the stem.
Diaphragm — a dome; the classic pneumatic control-valve actuator.
Piston / cylinder — a rectangle; spring-return or double-acting.
Motor — a circle marked M for an electric (MOV) actuator.
Solenoid — a small block marked S, usually for on/off.

Fail-safe position

Control valves carry a fail-safe annotation telling you where they go on loss of air or power — critical for safety reviews:

FC — fail closed
FO — fail open
FL — fail last (stays put) / locked

Reading the valve tag

Control valves use an ISA-5.1 tag: FCV-104 is a flow control valve on loop 104; PCV pressure, TCV temperature, LCV level. Hand valves are often HV, and relief valves PSV / PRV. The full letter table is in our ISA-5.1 reference.

Relief & safety valves

Pressure relief (PSV) and safety valves get a spring-loaded body and belong to the safety family alongside rupture discs, flame arrestors and breather valves — see the Safety category in the catalog.

Download valve symbols as PNG / SVG

Filter the catalog to Valves, tweak the palette, and export — or compose your own in the builder. Free, no account.

Browse valve symbols → Open the builder →

Frequently asked questions

What does a control valve symbol look like?

A valve body (usually a globe bow-tie) topped by an actuator — a diaphragm dome, a piston, a motor M or a solenoid — tagged with a control function like FCV, PCV or TCV.

Gate vs globe valve symbol — what's the difference?

Both use the bow-tie body. A globe valve adds a filled circle at the center (the plug); a plain bow-tie is the generic gate / on-off valve. Globe throttles, gate isolates.

What do FC, FO and FL mean?

Fail-safe positions: FC fail closed, FO fail open, FL fail last/locked — where the valve goes when its actuator loses air or power.

Where can I download valve symbols?

Browse and download ISA-compliant valve symbols as PNG or SVG from the catalog (Valves), or build your own in the Symbol Builder.

Keep reading

P&ID symbols explained — the full guide to every symbol family.
ISA-5.1 instrumentation symbols reference — tag letters & bubbles.
The 9 motor states every HMI should show.
Build your own symbols — free online editor.