What is P & ID?
P&ID stands for “process and instrumentation diagram,” and it is a detailed graphic representation of a process that also includes the hardware and software required to design, construct, and control the facility. This representation is applicable in the Process Industry Practices (PIP).
Valve PID Symbol:
Line PID Symbol:
| SYMBOL | FUNCTION |
|---|
 | Future Equipment |
 | Major Process |
 | Minor Process |
 | Pneumatic Signal |
 | Hydraulic Signal |
 | Capillary Tubing |
 | Mechanical Link Signal |
 | Electromagnetic, Sonic, Optical, Nuclear Signal |
 | Electric Signal |
 | Connecting Line |
 | Non-Connecting Line |
 | Non-Connecting Line |
 | Jacketed or Double Containment |
 | Data or Software Link |
 | Self Contained Regulator |
Instrument PID Symbol:
| CIRCLE AND LETTERS REPRESENTATION | FUNCTION |
|---|
 | A circle with letters represents a field or locally mounted instrument |
| A | Analysis |
| B | Burner |
| C | Combustion |
| D | Differential |
| E | Voltage |
| F | Flow Rate |
| G | User Choice’s (1) |
| H | Hard |
| I | Current |
| J | Power |
| K | Time, Time Schedule |
| L | Level |
| M | Momentary |
| N | User Choice’s (1) |
| O | User Choice’s (1) |
| P | Pressure, Vacuum |
| Q | Quantity |
| R | Radiation |
| S | Speed, Frequency |
| T | Temperature |
| U | Multi-variable |
| V | Vibration |
| W | Weight, Force |
| X | Unclassified |
| Y | State or Presence |
| Z | Position, Dimension |
| FC | Flow Controller |
| FE | Flow Element |
| FI | Flow Indicator |
| FT | Flow Transmitter |
| FS | Flow Switch |
| FIC | Flow Indicating Controller |
| FCV | Flow Control Valve |
| FRC | Flow Recording Controller |
| LC | Level Controller |
| LG | Level Gauge |
| LR | Level Recorder |
| LT | Level Transmitter |
| LS | Level Switch |
| LIC | Level Indicating Controller |
| LCV | Level Control Valve |
| LRC | Level Recording Controller |
| PC | Pressure Controller |
| PG | Pressure Gauge |
| PI | Pressure Indictor |
| PR | Pressure Recorder |
| PS | Pressure Switch |
| PT | Pressure Transmitter |
| PIC | Pressure Indicating Controller |
| PCV | Pressure Control Valve |
| PRC | Pressure Recording Controller |
| PDI | Pressure Differential Indicator |
| 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 |
Mechanical PID Symbol:
| SYMBOL | FUNCTION |
|---|
 | Heater |
 | Vessel or Reactor |
 | Heat Exchanger |
 | Pipe |
 | Pump |
 | Flow Direction of Pump |
 | Boiler |
 | Centrifugee |
 | Cylinder or Horizontal Tank |
 | Liquid Mixer |
 | Reaction Chamber |
 | Distillation Column |
 | Absorber |
 | Stripper |
 | Diesel Motor |
 | Agitator or Mixer |
 | Liquid Flow rate |
 | Gas Flow rate |
 | Crossflow Cooling Tower |
 | Chimney Cooling Tower |
 | Fan |
Pump PID Symbol:
| SYMBOL | FUNCTION |
|---|
 | Centrifugal Pump |
 | Horizontal Pump |
 | Vertical Pump |
 | Sump Pump |
 | Positive Displacement Pump |
 | Progressive Cavity Pump |
 | Screw Pump |
 | Vacuum Pump |
 | Reciprocating Pump |
 | Positive Displacement Pump |
 | Gear Pump |
 | Vertical Can Pump |
Compressor PID Symbol:
| SYMBOL | FUNCTION |
|---|
 | Centrifugal Compressor |
 | Centrifugal Blower |
 | Turbine Driven Centrifugal Compressor |
 | Axial Compressor |
 | Reciprocating Compressor |
 | Rotary Compressor |
 | Rotary Compressor & Silencer |
 | Liquid Ring Vacuum |
 | Rotary Screw Compressor |
 | Positive Displacement Blower |
Pipe PID Symbol:
| SYMBOL | FUNCTION |
|---|
 | Generic Pipe |
 | Threaded Pipe |
 | Socket Welded Pipe |
 | Flanged Pipe |
 | Heat/Cool Traced Pipe |
 | Direct Welded Pipe |
HEAT Exchanger PID Symbol:
| SYMBOL | FUNCTION |
|---|
 | Plate and Frame Heat Exchanger |
 | Hairpin Exchanger |
 | Air Cooled Exchanger |
 | U-Tube Heat Exchanger |
 | Double-Pipe Heat Exchanger |
 | Single Pass Heat Exchanger |
 | Spiral Heat Exchanger |
 | Reboiler |
 | Heater |
 | Condenser |
 | Shell and Tube Heat Exchanger |
Function PID Symbol:
| SYMBOL | FUNCTION |
|---|
 | Field |
 | Control Panel |
 | DCS |
 | PLC |
Actuator PID Symbol:
| SYMBOL | FUNCTION |
|---|
 | Manual Actuator |
 | Spring Diaphragm Actuator |
 | Linear Piston Pneumatic Actuator |
 | Rotary Piston Pneumatic Actuator |
 | Rotary Motor Actuator |
Positioner PID Symbol:
| SYMBOL | FUNCTION |
|---|
 | Positoner |
 | Fail Positioner |
 | Manual Override Positioner |
