Contents and Function
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:
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 Instrumentation, Systems, and Automation Society (ISA) Standard S5. 1.
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 and
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
D
Density
E
Electricity
F
Flow
H
Hand
J
Power
K
Time, Time Schedule
L
Level
M
Moisture
P
Pressure
Q
Quality
R
Radiation
S
Speed, Frequency
T
Temperature
V
Viscosity
W
Weight
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 instrumentation
Below are listed some symbols of chemical apparatus and instrumentation normally used in a P&ID, according to DIN 30600 and ISO 14617.
Symbols of chemical apparatus and instrumentation
Pipe
Thermally insulated pipe
Jacketed pipe
Cooled or heated pipe
Jacketed mixing vessel (autoclave)
Half pipe mixing vessel
Pressurized horizontal vessel
Pressurized vertical vessel
Pump
Vacuum pump or compressor
Bag
Gas bottle
Fan
Axial fan
Radial fan
Dryer
Packing column
Tray column
Furnace
Cooling tower
Heat exchanger
Heat exchanger
Cooler
Plate & frame heat exchanger
Double pipe heat exchanger
Fixed straight tubes heat exchanger
U shaped tubes heat exchanger
Spiral heat exchanger
Covered gas vent
Curved gas vent
Dust trap
Funnel
Steam trap
Viewing glass
Pressure reducing valve
Flexible pipe
Valve
Control valve
Manual valve
Back draft damper
Needle valve
Butterfly valve
Diaphragm valve
Ball valve
See also
Commons:Category:Chemical engineering symbols - A list of P&ID symbols in SVG format
Process flow diagram
External links
ISA-5.1-1984 (R1992), Instrumentation Symbols and Identification
The P&ID at The Engineering Tool Box
ISO reference for P&ID symbols
Engineering Symbology, Prints and Drawing pdf book free download
How to read P&IDs
Categories: Engineering | Piping | Diagrams
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