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P&ID Symbols
(Complete List)
A complete collection of the most used
P&ID symbols for lines, piping, valves,
instruments, pumps, compressors,
pressure equipment and other mechanical
equipment.
Table of Content [show]
WHAT IS P&ID?
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P&ID is the acronym for “Piping and
instrumentation diagram”, i.e. a very
detailed diagram showing the processes
happening within a plant, the involved
equipment, and their interconnections.
A set of standardized P&ID symbols is
used by process engineers to draft such
diagrams. P&ID symbols exist for all major
components and lines, such as valves,
vessels, instruments, pumps,
compressors, and towers. The ISA S5.1,
ISO 10628, and BS 5070 cover the
standardization of P&ID symbols and
guide process engineers in their plant
design activities.
The most common P&ID symbols are
listed below:
lines
piping components (pipes, flanges, and
fittings)
valves
filters
instruments and instrumentation
pumps
compressors
vessels
electrical machines (motors, generators,
and turbines)
heat exchangers
LINES P&ID SYMBOLS
PIPING P&ID SYMBOLS
Clamped Flange
Coupling symbol
Coupling symbol
End Caps 01 symbol
End Caps 02 symbol
Flange symbol
Flanges symbol
Reducers symbol
Removable Spool symbol
Union symbol
VALVES P&ID SYMBOLS
Gate Valve
symbol
Normally Closed
Gate Valve
symbol
Ball Valve
symbol
Normally Closed
Ball Valve
symbol
Globe Valve
symbol
Butterfly Valve
symbol
Check Valve
symbol
Plug Valve
symbol
Needle Valve
symbol
Self Draining
Valve symbol
Integrated Block
and Bleed Valve
symbol
Auto
Recirculation
Valve symbol
Angle Valve
symbol
Angle Globe
Valve symbol
3-way Valve
symbol
Y Blowdown
Valve symbol
Angle Blowdown
Valve symbol
FILTERS P&ID SYMBOLS
INSTRUMENTS P&ID
SYMBOLS
Analyzer Transmitter
symbol
AND Gate symbol
Averaging Pitot Tube
symbol
Behind Control symbol
Behind Local Control
symbol
Computer symbol
Computer Indicator
symbol
Coriolis Flow Sensor
symbol
Correcting Element
symbol
Diamond symbol
Diaphragm Meter symbol
Displayed Configurable
symbol
Displayed Programmable
Indicator symbol
Double symbol
Flow Controller symbol
Flow Element symbol
Flow Indicator symbol
Flow Meter symbol
Flow Nozzle Meter symbol
Flow Recorder symbol
Flow Transmitter symbol
Flowmeter symbol
Flume Meter symbol
Indicator 01 symbol
Level Alarm symbol
Level Controller symbol
Level Gauge symbol
Level Indicator symbol
Level Meter symbol
Level Recorder symbol
Level Transmitter symbol
Magnetic Flow Meter
symbol
Manhole symbol
NOT Gate symbol
Odometer symbol
On Central Control Panel
symbol
On Local Control Panel
symbol
OR Gate symbol
Pitot Tube symbol
Pitot Tube Type Flow
Meter symbol
Pressure Controller
symbol
Pressure Gauge symbol
Pressure Gauges symbol
Pressure Indicating
controller symbol
Pressure Indicator symbol
Pressure Recorder symbol
Pressure Recording
Controller symbol
Pressure Transmitter
symbol
Programmable Indicator
symbol
Quick Change Meter
symbol
Rotary Meter symbol
Rotometer symbol
Sampler symbol
Shared Indicator 01
symbol
Shared Indicator 02
symbol
Socket Connection
symbol
Specialty Item symbol
Steam Tracer symbol
Straightening Vane
symbol
Support Bracket symbol
Support Leg symbol
Support Ring symbol
Support Skirt symbol
Target Meter symbol
Temperature Controller
symbol
Temperature Element
symbol
Temperature Indicator
symbol
Temperature Recorder
symbol
Temperature Transmitter
symbol
Thermometer symbol
Thermometers symbol
Transducer symbol
Turbine Meter symbol
Ultrasonic Meter symbol
Unit Control Panel symbol
V Cone Meter symbol
Venturi symbol
Venturi Meter symbol
Vortex Sensor symbol
Wedge Meter symbol
Weir Meter symbol
ISA SYMBOLOGY
The symbology for the identification of the
measurement and control instrumentation
on the flow and process diagrams and on
the P&ID (Piping & Instrument Diagram),
commonly called P&I (Piping &
Instrumentation), is generally compliant
with the Standard ISA (Instrumentation
Society of Automation) identified as S.5,
that is composed of identification codes
and graphic symbols.
The symbology of the instrument it is
placed in a circle of 7/16 “or 12 mm (see
below), was in the top there is the
functional identification (of the instrument
or device) composed with max 5 letters,
and in the bottom there is identification of
the loop (measurement and/or control)
consists of a progressive number of 3 or 4
numbers, followed by a literal suffix to
identifies two or more identical
instruments inserted in the same chain
and therefore having the same functional
identification;
The circle that identifies the instrument or
device has:
Continue Line in the center: for an
instrument suitable for control room
mounting
The dotted line in the center: for an
instrument suitable for technical room
mounting
No line in the center: for an instrument
suitable for field application
If an instrument has a circumscribed
square means that it is an integrated
instrument as a function in a DCS
(Distributed Control System) or PLC
(Programmable Logic Controller).
T
RC
First 101
Later A
Letter Loop
letters Suffix
(Measured number
(Functions)
variable)
Loop
Functional identification
identification
Graphical representation of a
temperature recorder controller of the
101A loop, suitable for control room
mounting
The following tables show:
– Table 1 identifying the function of the
instruments or devices
– Table 2 the graphic identification of the
valves
– Table 3 the graphic identification of the
actuators
– Table 4 identifying the safety conditions
of the valves and actuators
At the end will also be reported the literal
and graphic symbols of the power
supplies and signals of the
instrumentation.
