Piping and instrumentation diagram

File:Pump with tank pid en.svg

Piping and instrumentation diagram of pump with storage tank. Symbols according to EN ISO 10628 and EN 62424.

A piping and instrumentation diagram/drawing (P&ID) is a diagram in the process industry which shows the piping of the process flow together with the installed equipment and instrumentation.

Contents and Function

File:P&ID.JPG

An example of a P&ID.

A piping and instrumentation diagram/drawing (P&ID) is defined by the Institute of Instrumentation and Control as follows:

1. A diagram which shows the interconnection of process equipment and the instrumentation used to control the process. In the process industry, a standard set of symbols is used to prepare drawings of processes. The instrument symbols used in these drawings are generally based on International Society of Automation (ISA) Standard S5. 1.
2. The primary schematic drawing used for laying out a process control installation.

P&IDs play a significant role in the maintenance and modification of the process that it describes. It is critical to demonstrate the physical sequence of equipment and systems, as well as how these systems connect. During the design stage, the diagram also provides the basis for the development of system control schemes, allowing for further safety and operational investigations, such as the hazard and operability study (HAZOP).

For processing facilities, it is a pictorial representation of

• Key piping and instrument details
• Control and shutdown schemes
• Safety and regulatory requirements
• Basic start up and operational information

List of P&ID items

• Instrumentation and designations
• Mechanical equipment with names and numbers
• All valves and their identifications
• Process piping, sizes and identification
• Miscellanea - vents, drains, special fittings, sampling lines, reducers, increasers and swagers

• Permanent start-up and flush lines
• Flow directions
• Interconnections references
• Control inputs and outputs, interlocks
• Interfaces for class changes
• Computer control system input
• Identification of components and subsystems delivered by others

Identification and Reference Designation

The P&ID is used for the identification of measurements within the process. Identification letters for measurements are based on Standard S5. 1 and ISO 14617-6:

First-Letter	Measurement
A	Analysis
B	Burner, Combustion
C	User's Choice (usually Conductivity)
D	User's Choice (usually Density)
E	Voltage
F	Flow
G	User's Choice
H	Hand
I	Current
J	Power
K	Time, Time Schedule
L	Level
M	User's Choice
N	User's Choice (usually Torque)
O	User's Choice
P	Pressure
Q	Quantity
R	Radiation
S	Speed, Frequency
T	Temperature
U	User's Choice (usually Alarm Output)
V	Vibration, Mechanical Analysis
W	Weight, Force
X	User's Choice (usually on-off valve as XV)
Y	Event, State, Presence
Z	Position, Dimension

For reference designation of any equipment in industrial systems the standard IEC 61346 (Industrial systems, installations and equipment and industrial products — Structuring principles and reference designations) can be applied. For the function Measurement the reference designator B is used, followed by the above listed letter for the measured variable.

For reference designation of any equipment in a power station the KKS Power Plant Classification System can be applied.

Symbols of chemical apparatus and equipments

Below are listed some symbols of chemical apparatus and equipment normally used in a P&ID, according to DIN 30600 and ISO 14617.

Symbols of chemical apparatus and equipment

80px	Pipe	80px	Thermally insulated pipe	80px	Jacketed pipe	80px	Cooled or heated pipe
80px	Jacketed mixing vessel (autoclave)	80px	Half pipe mixing vessel	80px	Pressurized horizontal vessel	80px	Pressurized vertical vessel
80px	Pump	80px	Vacuum pump or compressor	80px	Bag	80px	Gas bottle
80px	Fan	80px	Axial fan	80px	Radial fan	80px	Dryer
80px	Packing column	80px	Tray column	80px	Furnace	80px	Cooling tower
80px	Heat exchanger	80px	Heat exchanger	80px	Cooler	80px	Plate & frame heat exchanger
80px	Double pipe heat exchanger	80px	Fixed straight tubes heat exchanger	80px	U shaped tubes heat exchanger	80px	Spiral heat exchanger
80px	Covered gas vent	80px	Curved gas vent	80px	(Air) filter	80px	Funnel
80px	Steam trap	80px	Viewing glass	80px	Pressure reducing valve	80px	Flexible pipe
80px	Valve	80px	Control valve	80px	Manual valve	80px	Back draft damper
80px	Needle valve	80px	Butterfly valve	80px	Diaphragm valve	80px	Ball valve

See also

• Commons:Category:Chemical engineering symbols - A list of P&ID symbols in SVG format
• Process flow diagram

External links

• How to read P&IDsde:R&I-Fließschema