P&ID Instrument Symbols – List of Instrument Symbols in PID

This article is about P&ID Instrument Symbols. P&ID stands for “Piping and Instrumentation Diagram.” It is a schematic representation of a process system in various industries, including chemical, petrochemical, pharmaceutical, power generation, and others. P&ID diagrams provide a visual representation of how different components, equipment, pipes, instruments, and control systems are interconnected and work together within a process.

Key components of a P&ID include:

1. Piping: The various pipes that carry fluids (liquids or gases) within the process are depicted with different lines, sizes, and types to indicate the type of material being transported and the direction of flow.
2. Equipment: Major equipment such as pumps, compressors, heat exchangers, reactors, and more are represented by symbols that show their basic shape and function.
3. Instruments: Sensors, valves, transmitters, controllers, and other instruments used to monitor and control the process are represented with symbols that convey their purpose and the information they provide.
4. Valves: Different types of valves, such as control valves, isolation valves, relief valves, and more, are indicated by specific symbols that represent their design and function.
5. Control Loops: The control systems and loops used to regulate the process are depicted, showing how instruments and devices interact to maintain desired process parameters.
6. Annotations and Notes: P&IDs include labels, annotations, and notes to provide additional information about components, process conditions, materials, and other important details.
7. Flow Directions and Connections: Arrows indicate the direction of fluid flow within pipes, helping to understand the flow path throughout the process.

P&IDs are essential in various stages of a process, from design and construction to operation and maintenance. They aid in communication between engineers, operators, and other stakeholders, ensuring a common understanding of the process system’s layout, functionality, and control. These diagrams also play a vital role in safety, as they help identify potential hazards, emergency shutdown procedures, and isolation points.

List of Instrument symbols in PID

1. Sonic signal
2. Hydraulic line
3. Software link
4. Instrument electrical line
5. Pneumatic transmission or Air line
6. Capillary tubing or Filled system
7. Mechanical link or instrument air tubing
8. Instrument shown elsewhere and outside scope of work
9. Heat traced instrument
10. Orifice plate
11. Restriction orifice
12. Flow nozzle
13. Wedge meter
14. Venture tube
15. Flow meter (Positive displacement type, Turbine, Coriolis, magnetic, Vortex shedding, integral orifice, ultrasonic, insertion tubing , thermal mass flow, target meter)
16. Averaging pitot tube
17. Rotameter
18. Float type level controller
19. Diaphragm operated globe valve with hand operated
20. Diaphragm operated butterfly valve

P&ID Instrument Symbols

Following picture shows instrument P&ID symbols and different letter represents different instruments used in industry.

Instrument Letter Representation	Letters shows a field or locally mounted instrument.
A	Analysis	B	Burner
C	Combustion	D	Differential
F	Flow Rate	E	Voltage
FCV	Flow Control Valve	FRC	Flow Recording Controller
FI	Flow Indicator	FT	Flow Transmitter
FC	Flow Controller	FE	Flow Element
FS	Flow Switch	FIC	Flow Indicating Controller
G	User Choice’s (1)	H	Hard
I	Current	J	Power
K	Time, Time Schedule	M	Momentary
N	User Choice’s (1)	O	User Choice’s (1)
LCV	Level Control Valve	LRC	Level Recording Controller
LR	Level Recorder	LT	Level Transmitter
LC	Level Controller	LG	Level Gauge
LS	Level Switch	LIC	Level Indicating Controller
L	Level
PC	Pressure Controller	PG	Pressure Gauge
PI	Pressure Indictor	PR	Pressure Recorder
P	Pressure, Vacuum
PRC	Pressure Recording Controller	PDI	Pressure Differential Indicator
PS	Pressure Switch	PT	Pressure Transmitter
PIC	Pressure Indicating Controller	PCV	Pressure Control Valve
PDR	Pressure Differential Recorder	PDS	Pressure Differential Switch
PDT	Pressure Differential Transmitter	PTD	Pressure Transducer
TC	Temperature Controller	TE	Temperature Element
TR	Temperature Recorder	TS	Temperature Switch
TT	Temperature Transmitter	TI	Temperature Indicator
T	Temperature	Q	Quantity
R	Radiation	S	Speed, Frequency
U	Multi-variable	V	Vibration
W	Weight, Force	X	Unclassified
Y	State or Presence	Z	Position, Dimension