A piping and instrumentation diagram (P&ID or PID) is a detailed diagram in the
process industry
Industrial processes are procedures involving chemical, physical, electrical or mechanical steps to aid in the manufacturing of an item or items, usually carried out on a very large scale. Industrial processes are the key components of heavy ind ...
which shows the
piping
Within industry, piping is a system of pipes used to convey fluids (liquids and gases) from one location to another. The engineering discipline of piping design studies the efficient transport of fluid.
Industrial process piping (and accompan ...
and process equipment together with the
instrumentation
Instrumentation a collective term for measuring instruments that are used for indicating, measuring and recording physical quantities. The term has its origins in the art and science of scientific instrument-making.
Instrumentation can refer to ...
and control devices.
Superordinate to the P&ID is the
process flow diagram (PFD) which indicates the more general flow of plant processes and the relationship between major equipment of a plant facility.
Contents and function
![Industrial control loop](https://upload.wikimedia.org/wikipedia/commons/6/6a/Industrial_control_loop.jpg)
A piping and instrumentation diagram (P&ID) is defined 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
International Society of Automation
The International Society of Automation (ISA), formerly known as The Instrumentation, Systems, and Automation Society, is a non-profit technical society for engineers, technicians, businesspeople, educators and students, who work, study or are int ...
(ISA) Standard S5.1
# The primary schematic drawing used for laying out a
process control
An industrial process control in continuous production processes is a discipline that uses industrial control systems to achieve a production level of consistency, economy and safety which could not be achieved purely by human manual control. I ...
installation.
They usually contain the following information:
* Mechanical equipment, including:
**
Pressure vessels
A pressure vessel is a container designed to hold gases or liquids at a pressure substantially different from the ambient pressure.
Construction methods and materials may be chosen to suit the pressure application, and will depend on the size o ...
, columns, tanks,
pumps
A pump is a device that moves fluids (liquids or gases), or sometimes slurries, by mechanical action, typically converted from electrical energy into hydraulic energy. Pumps can be classified into three major groups according to the method they u ...
,
compressors
A compressor is a mechanical device that increases the pressure of a gas by reducing its volume. An air compressor is a specific type of gas compressor.
Compressors are similar to pumps: both increase the pressure on a fluid and both can transp ...
,
heat exchangers
A heat exchanger is a system used to transfer heat between a source and a working fluid. Heat exchangers are used in both cooling and heating processes. The fluids may be separated by a solid wall to prevent mixing or they may be in direct contac ...
,
furnaces
A furnace is a structure in which heat is produced with the help of combustion.
Furnace may also refer to:
Appliances Buildings
* Furnace (central heating): a furnace , or a heater or boiler , used to generate heat for buildings
* Boiler, used t ...
,
wellheads, fans,
cooling towers
A cooling tower is a device that rejects waste heat to the atmosphere through the cooling of a coolant stream, usually a water stream to a lower temperature. Cooling towers may either use the evaporation of water to remove process heat and ...
,
turbo-expanders,
pig traps (see 'symbols' below)
**
Bursting discs, restriction orifices, strainers and filters,
steam traps, moisture traps, sight-glasses, silencers, flares and vents,
flame arrestors, vortex breakers,
eductors
*Process piping, sizes and identification, including:
**Pipe classes and piping line numbers
**Flow directions
**Interconnections references
**Permanent start-up, flush and bypass lines
**Pipelines and flowlines
**Blinds and spectacle blinds
**Insulation and heat tracing
*Process control instrumentation and designation (names, numbers, unique tag identifiers), including:
**Valves and their types and identifications (e.g. isolation, shutoff, relief and
safety valve
A safety valve is a valve that acts as a fail-safe. An example of safety valve is a pressure relief valve (PRV), which automatically releases a substance from a boiler, pressure vessel, or other system, when the pressure or temperature exceeds ...
s, valve interlocks)
**Control inputs and outputs (
sensor
A sensor is a device that produces an output signal for the purpose of sensing a physical phenomenon.
In the broadest definition, a sensor is a device, module, machine, or subsystem that detects events or changes in its environment and sends ...
s and final elements, interlocks)
**Miscellaneous - vents, drains,
flange
A flange is a protruded ridge, lip or rim (wheel), rim, either external or internal, that serves to increase shear strength, strength (as the flange of an iron beam (structure), beam such as an I-beam or a T-beam); for easy attachment/transfer of ...
s, special fittings, sampling lines, reducers and swages
*Interfaces for class changes
*Computer control system
*Identification of components and subsystems delivered by others
P&IDs are originally drawn up at the design stage from a combination of process flow sheet data, the mechanical process equipment design, and the instrumentation engineering design. 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 a
Hazard and operability study A hazard and operability study (HAZOP) is a structured and systematic examination of a complex plan or operation in order to identify and evaluate problems that may represent risks to personnel or equipment. The intention of performing a HAZOP is to ...
(HAZOP). To do this, it is critical to demonstrate the physical sequence of equipment and systems, as well as how these systems connect.
P&IDs also play a significant role in the maintenance and modification of the process after initial build. Modifications are red-penned onto the diagrams and are vital records of the current plant design.
They are also vital in enabling development of;
*Control and shutdown schemes
*Safety and regulatory requirements
*Start-up sequences
*Operational understanding.
P&IDs form the basis for the live mimic diagrams displayed on
graphical user interface
The GUI ( "UI" by itself is still usually pronounced . or ), graphical user interface, is a form of user interface that allows users to interact with electronic devices through graphical icons and audio indicator such as primary notation, inste ...
s of large
industrial control system
An industrial control system (ICS) is an electronic control system and associated instrumentation used for industrial process control. Control systems can range in size from a few modular panel-mounted controllers to large interconnected and in ...
s such as
SCADA
Supervisory control and data acquisition (SCADA) is a control system architecture comprising computers, networked data communications and graphical user interfaces for high-level supervision of machines and processes. It also covers sensors and ...
and
distributed control system
A distributed control system (DCS) is a computerised control system for a process or plant usually with many control loops, in which autonomous controllers are distributed throughout the system, but there is no central operator supervisory contro ...
s.
Identification and reference designation
Based on STANDARD
ANSI
The American National Standards Institute (ANSI ) is a private non-profit organization that oversees the development of voluntary consensus standards for products, services, processes, systems, and personnel in the United States. The organi ...
/
ISA S5.1 and
ISO 14617
ISO 14617 ''Graphical symbols for diagrams'' is a library of graphical symbols for diagrams used in technical applications. ISO 14617 consists of the following parts:
* Part 1: General information and indexes
* Part 2: Symbols having general appli ...
-6, the P&ID is used for the identification of measurements within the process. The identifications consist of up to 5 letters. The first identification letter is for the measured value, the second is a modifier, 3rd indicates passive/readout function, 4th - active/output function, and the 5th is the function modifier. This is followed by loop number, which is unique to that loop. For instance FIC045 means it is the Flow Indicating Controller in control loop 045. This is also known as the "tag" identifier of the field device, which is normally given to the location and function of the instrument. The same loop may have FT045 - which is the flow transmitter in the same loop.
For reference designation of any equipment in industrial systems the standard
IEC 61346
International Standard IEC/ISO 81346 series "Industrial systems, installations and equipment and industrial products – structuring principles and reference designations" defines the rules for reference designation systems (RDS). It is publish ...
(''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 KKS could refer to:
* KKS 1925 Kalisz, a football club in Poland
* Giiwo language (ISO 639-3 code), an Afro-Asiatic language spoken in Nigeria
* Kankesanthurai, Sri Lanka
* Kinin–kallikrein system, a hormonal system
* Kirk Sandall railway stat ...
can be applied.
Symbols of chemical apparatus and equipment
Below are listed some symbols of chemical apparatus and equipment normally used in a P&ID, according to
ISO 10628
ISO 10628 ''Diagrams for the chemical and petrochemical industry
The petrochemical industry is concerned with the production and trade of petrochemicals. A major part is constituted by the plastics (polymer) industry. It directly interfaces with ...
and
ISO 14617
ISO 14617 ''Graphical symbols for diagrams'' is a library of graphical symbols for diagrams used in technical applications. ISO 14617 consists of the following parts:
* Part 1: General information and indexes
* Part 2: Symbols having general appli ...
.
Historical use
Prior to the advent of
computer-aided design
Computer-aided design (CAD) is the use of computers (or ) to aid in the creation, modification, analysis, or optimization of a design. This software is used to increase the productivity of the designer, improve the quality of design, improve c ...
(CAD) in the late 1980s, P&IDs were drawn by hand. The drawing template shown below, actual size 225 mm by 111 mm, is typical of those used to draw P&IDs.
![P&ID_drawing_template](https://upload.wikimedia.org/wikipedia/commons/3/3a/P%26ID_drawing_template.jpg)
Piping and instrumentation diagram manual drawing template (1980s). Symbol key: {{ordered list
, list-style-type=upper-alpha;
, Vessel dished end
, Motor driven pump or compressor and baseplate
, Valves
, Valve diaphragm actuator
,
Shell and tube heat exchanger
A shell and tube heat exchanger is a class of heat exchanger designs. It is the most common type of heat exchanger in oil refineries and other large chemical processes, and is suited for higher-pressure applications. As its name implies, this ty ...
, Flexible hose, bellows
,
Ejector
, Machine driven pump or other device
, Reducers
See also
*
Instrumentation in petrochemical industries
Instrumentation is used to monitor and control the process plant in the oil, gas and petrochemical industries. Instrumentation ensures that the plant operates within defined parameters to produce materials of consistent quality and within the requi ...
External links
*
Commons:Chemical engineering symbols - A list of P&ID symbols in
SVG format
Process engineering
Piping
Diagrams
Industrial automation
Learn How to Read P&ID Drawings – A Complete GuideInterpreting Piping and Instrumentation Diagrams-Symbology