P&ID symbols

What each symbol on a P&ID looks like, what it means, and which Deck Twin component it becomes. The conventions are ISO 10628-2 and PIP PIC001 for process, ISA 5.1 for instruments, IEC 60617 for electrical, and NFPA 170 / ISO 7010 for fire & gas. Company legends vary, so read the drawing's own legend sheet first.

For agents: pid-legend.md · pid-symbols.md · pid-library.json · legend.svg

Filter: gate, PSV, FC, off-pageSymbol categoryAll categories (293)Valves (23)Check valves (6)Relief, regulators and safety devices (9)Actuators, operators and valve accessories (25)Piping fittings and specials (37)Lines and signals (16)Connectors, boundaries and annotations (11)Instrument bubbles and functions (ISA 5.1) (14)Primary elements and field instruments (30)Vessels, columns and tanks (13)Heat transfer equipment (12)Pumps (9)Compressors, blowers and drivers (15)Filters, separators and mixers (10)Flare, wellhead, pipeline and packages (16)Fire & gas and fire protection (24)Electrical (single-line) (23)

All293Has 3D model162Symbol only131

Showing 293 of 293

Gate valve

3DHV

Globe valve

3DHV

Ball valve

3DHV

Ball valve, encircled style

3DHV

Butterfly valve

3DHV

Plug valve

3DHV

Needle valve

3DHV

Diaphragm valve

HV

Pinch valve

HV

Knife gate valve

3DHV

Angle valve

HV

Three-way valve

HV · TV · XV

Four-way valve

HV · XV

Normally closed valve

3DHV

Locked open valve

3DHV

Locked closed valve

3DHV

Car-sealed open valve

3DHV

Car-sealed closed valve

3DHV

Float-operated valve

LCV · LV

Double block and bleed

HV

Damper (louvre)

HD · FD · MD

Fixed (positive) choke

3DCH · FO

Adjustable choke

3DHCV · CH · PCV

Check valve (general)

3DNRV · CV

Swing check valve

3DNRV

Lift (piston) check valve

3DNRV

Ball check valve

NRV

Dual-plate check valve

3DNRV

Stop-check valve

NRV

Pressure safety valve (spring loaded)

3DPSV · PRV · TSV · SV · PSV · PRV · TSV

Pilot-operated relief valve

3DPSV · PSV

Pressure-vacuum (breather) valve

PVRV · PSV

Rupture disc (bursting disc)

3DPSE · RD · BD · PSE

Flame arrester

FA

Self-actuated pressure regulator (PCV)

PCV · PCV

Back-pressure regulator

PCV · BPR · PCV

Self-actuated temperature regulator

TCV · TCV

Excess-flow valve

EFV

Handwheel operator

3DHV

Lever operator

3DHV

Gear operator

3DHV

Manual operator with position indicator

HV · ZI

Diaphragm actuator (control valve)

3DFV · LV · PV · TV · FCV · LCV · PCV · TCV · FV · LV · PV · TV · HV

Valve positioner

3DZC · FY · LY · PY · ZC

Piston actuator, single acting (spring return)

3DESDV · SDV · XV · XV · SDV

Piston actuator, double acting

XV · HV · XV

Electric motor actuator (MOV)

3DMOV · XV · HV · XV · HV

Solenoid actuator / solenoid valve (SOV)

SOV · XY · XV · XY · XV

Electro-hydraulic actuator

XV · ESDV · SDV · XV

Hydraulic actuator

XV · SSV · SCSSV · XV

Emergency shutdown valve (ESDV)

3DESDV · SDV · XV · SSIV · XV · UV

Blowdown valve (BDV)

3DBDV · BDV

Fail open (FO), arrow form

logicalFO

Fail closed (FC), arrow form

logicalFC

Fail locked (last position) (FL), arrow form

logicalFL

Fail indeterminate (FI), arrow form

logicalFI

Fail open (FO), letter form

logicalFO

Fail closed (FC), letter form

logicalFC

Fail locked (last position) (FL), letter form

logicalFL

Fail indeterminate (FI), letter form

logicalFI

Valve limit switches (ZSO / ZSC)

ZSO · ZSC · ZSH · ZSL · ZSO · ZSC · ZSH · ZSL · ZS

I/P converter

FY · LY · PY · TY · FY · LY · PY · TY

Hand switch (HS)

HS · HS · HSS · HZ

Concentric reducer

3D

Eccentric reducer, flat on top (FOT)

3D

Eccentric reducer, flat on bottom (FOB)

3D

Spectacle blind, open (spacer in line)

3DSB

Spectacle blind, closed (blank in line)

3DSB

Spectacle blind, offset figure-8 (drawn beside the flanges)

3DSB

Spade (line blank)

Spacer (ring spacer)

Blind flange

3D

Flanged joint

3D

Pipe cap

Union

Flexible hose

3DFH

Expansion joint (bellows)

3DEJ

Y-strainer

3DS · STR

Basket (T-type) strainer

3DS · STR

Temporary (cone) strainer

TS

Steam trap

3DST · TR

Sight glass (sight flow indicator)

3DSG · FG · FG

Restriction orifice

3DRO · FO · FO · RO

Insulating joint (monolithic)

3DIJ

Drain funnel (tundish)

3DOD · TD

Hose connection

3DHC · UC

Vent with cap

VT

Drain with plug

DR

Sample connection

SC · SP · AX · SP

Piping specification break

logical

Insulation mark

logical

Electric heat tracing mark

logicalET · EHT

Steam tracing mark

logicalST

Slope (fall) mark

logical

Flow direction arrow

logical

Line crossing (no connection)

logical

Line junction (tee)

3D

Injection quill / point

IP · CI

Corrosion probe / coupon

CP · CC · CE

Vent to atmosphere (gooseneck)

VA · TV

Main process line

Secondary / minor process or utility line

Future line

logical

Existing line

Demolished / to be removed line

logical

Instrument supply / process connection

Pneumatic signal

logical

Hydraulic signal

logical

Electric signal

logical

Capillary tube (filled system)

Guided electromagnetic or sonic signal

logical

Unguided electromagnetic, radio or sonic signal

logical

Data link / software link

logical

Mechanical link

logical

Heat-traced line

Jacketed line

Off-page connector, outgoing

logical

Off-page connector, incoming

logical

Utility connector

logical

On-sheet continuation

logical

Tie-in point

logicalTP · TI

Battery limit

logicalBL

Package / vendor scope boundary

logical

Interlock / logic diamond

logicalI

Note reference

logical

Hold / revision cloud

logical

Revision marker

logical

Field-mounted instrument (discrete)

PI · PT · TT · LT · FT

Instrument in main control room (primary location)

logicalFIC · PIC · LIC · TIC · HS

Instrument on local / auxiliary panel

logicalPIC · HS · XA

Instrument behind the panel (not accessible)

logicalFY · PY · TY

Shared display / shared control (DCS)

logicalFIC · PIC · LIC · TIC · FI · PI · LI · TI

PLC / alternate control system function

logicalYIC · XC · HS

Safety instrumented system (SIS) function

logicalLSHH · PSHH · LZ · PZ · XS

Computer function

logicalFQ · UY · KY

Multi-function instrument (touching bubbles)

PIT · PSH · TT · TSH

Function block (computing / signal conversion)

logicalFY · TY · PY

Alarm and trip annotation

logicalH · HH · L · LL

ISA 5.1 identification letters

logical

Voting (MooN) annotation

logical

Condition monitoring / machinery protection system (CMS)

logical

Orifice plate flow element with dp transmitter

3DFE · FT · FE · FT · FIT

Venturi tube

FE · FE

Flow nozzle

FE · FE

Pitot tube

FE · FE

Averaging pitot (multiport probe)

FE · FE

Electromagnetic flowmeter

3DFE · FT · FE · FIT

Vortex flowmeter

3DFE · FT · FE · FIT

Turbine flowmeter

FE · FT · FE · FQ

Positive displacement flowmeter

FE · FQ · FQ · FQI

Ultrasonic flowmeter

3DFE · FT · FE · FIT · FQ

Coriolis mass flowmeter

3DFE · FT · FE · FIT · FQ

Variable-area flowmeter (rotameter)

FI · FG · FI · FG

Thermowell with temperature element / transmitter

3DTW · TE · TT · TW · TE · TT · TIT

Local temperature gauge

3DTI · TG · TI

Local pressure gauge

3DPI · PG · PI

Pressure transmitter

3DPT · PIT · PT · PIT · PZT

Differential pressure transmitter

3DPDT · PDIT · PDT · PDIT · PDI

Pressure switch

3DPS · PSH · PSL · PSHH · PSLL · PSH · PSL · PSHH · PSLL

Level gauge glass

LG · LG

Magnetic level gauge

3DLG · LI · LG · LI

Displacer level transmitter

LT · LT · LIT · LDT

Differential pressure level transmitter

3DLT · LT · LIT

Guided wave radar level transmitter

3DLT · LT · LIT

Non-contact radar level transmitter

LT · LT · LIT

Nuclear (gamma) level transmitter

LT · RE · LT · RE

Vibrating fork level switch

3DLS · LSH · LSL · LSHH · LSLL · LSH · LSL · LSHH · LSLL

Float level switch

LS · LSH · LSL · LSH · LSL

Analyser (with sample probe)

AT · AE · AIT · AT · AE · AIT · AI

Diaphragm (remote) seal with capillary

PT · LT

Vibration element / transmitter on a machine

3DVE · VT · VE · VT · VXE · VYE · VI · VSHH

Vertical vessel

3DV · D

Vertical scrubber with mist eliminator

3DV

Horizontal vessel

3DV · D

Three-phase separator (with boot and weir)

3DV

Trayed column

3DT · C

Packed column

3DT · C

Cone-roof storage tank

3DT · TK

Dome-roof storage tank

3DT · TK

Floating-roof tank

3DT · TK

Spherical tank (sphere)

3DT · TK · V

Bullet tank (horizontal pressure storage)

3DT · TK · V

Caisson (sump / pump caisson)

3DCS · X

Slug catcher (finger type)

3DV · SC

Heat exchanger (general)

3DE · HX

Shell-and-tube exchanger, fixed tubesheet (BEM)

3DE

Shell-and-tube exchanger, U-tube (BEU / AEU)

3DE

Shell-and-tube exchanger, floating head (AES)

3DE

Kettle reboiler

3DE

Condenser

3DE

Plate heat exchanger

3DE

Air-cooled exchanger (fin-fan)

3DE · AC

Double-pipe (hairpin) exchanger

3DE

Fired heater

3DH · F

Electric heater

3DE · H · EH

Cooling tower

3DCT

Centrifugal pump

3DP

Vertical in-line pump

3DP

Vertical turbine (caisson) pump

3DP

Submersible pump

3DP

Reciprocating (plunger) pump

3DP

Gear pump

P

Screw pump

P

Metering (dosing) pump

3DP

Progressive cavity pump

3DP

Centrifugal compressor

3DK · C

Reciprocating compressor

3DK · C

Screw compressor

3DK · C

Axial compressor

K · C

Blower / centrifugal fan

3DK · B · F · FN

Axial / propeller fan

F · FN · EF

Ejector / eductor

J · EJ · X

Turbo-expander (expander-compressor)

K · KT · EX

Gas turbine

GT · KT

Gas turbine generator set

3DGT · G · TG

Gas-turbine-driven compressor train

3DK · GT

Steam turbine

ST · KT · T

Electric motor (driver)

3DPM · KM · M

Diesel engine (driver)

DE · D

Diesel generator set

3DDG · EG · G

Filter (general)

F · S

Cartridge filter

3DF · S

Media filter (multimedia / nutshell)

3DF

Filter-separator / coalescer

3DV · F

Cyclone (gas-solid or gas-liquid)

V · CY

Hydrocyclone (de-oiling liner)

3DX · Z

Desander

3DV · DS

Agitator / mixer in vessel

A · AG · MX

Static (in-line) mixer

MX · X

Silencer

SL · X

Flare stack / tip

3DFS · FL · X

Flare boom

3DFB · X

Flare knock-out drum

3DV

Cold vent stack

3DVS · X

Pig launcher

3DL · PL

Pig receiver

3DL · PR

Christmas tree (wellhead valves)

3DXT · WH

Production / test manifold

3DM · MF

BOP stack

3DBOP

Riser

3DR

Package / skid (generic)

X · A · PK

Chemical injection package

3DC · X · CI

Fiscal metering skid

3DX · FQ

Meter prover (compact piston prover)

3DX

Hydraulic power unit (HPU)

3DX · HPU

Gas cylinder bank

3DX · N2

Point gas detector (flammable)

3DGD · GT · AT · AT · AE

Toxic gas detector (H2S, CO)

3DGD · TD · AT · AT

Open-path (line-of-sight) gas detector

3DOGD · OPGD · LOS

Acoustic (ultrasonic) gas leak detector

3DUGD · AGD · UGLD

Flame detector

3DFD · BS · IR3 · BE · BS

Heat detector

3DHD · TS · TSH

Smoke detector

3DSD

Manual call point (MAC)

3DMAC · MCP · HS · HS

Alarm beacon (visual)

3DXL · BCN · XL

Alarm sounder / bell

3DXA · SNDR · XA

PA/GA loudspeaker (horn)

3DLS · PA

Deluge valve

3DDV · XV · XV

Sprinkler head (closed)

3DSPK

Deluge (open) spray nozzle

3DNZ

Water mist nozzle / system

WM

Fire hydrant

3DHYD · FH

Fire monitor

3DFM · MON

Fire hose reel

3DHR

Portable fire extinguisher

3DEXT · FE

Firewater pump (diesel driven)

3DP · FWP

Foam system (concentrate tank and proportioner)

C · X

CO2 / inert gas extinguishing system

X · CO2

Safety shower and eyewash

3DSS · EW

Fusible plug loop

FP · TSE · TSE

Two-winding transformer

3DTR · T · TX

Three-winding transformer

3DTR · T

Circuit breaker

3DCB · Q

Disconnector (isolator)

3DDS · Q

Earthing switch

3DES

Fuse

F · FU

Contactor

K · KM

Motor (electrical)

3DM · PM

Generator

G

Variable frequency drive (VFD)

3DVFD · VSD · U

Uninterruptible power supply (UPS)

3DUPS

Battery

3DBAT · G

Busbar

logicalBB

Current transformer (CT)

3DCT · T

Voltage transformer (VT)

3DVT · PT

Surge arrester

3DSA · F

Earth (ground)

logicalE · PE

Capacitor

C

Neutral earthing resistor (NER)

3DNER · R

Switchboard / MCC

3DSWB · SWG · MCC

Junction box

3DJB

Local control station (LCS)

3DLCS · HS · HS

Protection relay (ANSI device number)

logicalR