181 Process Flow Diagram (PFD) Symbols for Engineers
Welcome to our process flow diagram symbols list. Scroll down and use the table of contents on the left to navigate this page and see the different symbol types most commonly used by engineers.
But first, let’s review the purpose and benefits of a PFD.
The Purpose and Benefits of a Process Flow Diagram
- An easy to understand structure, for high-quality control and in-depth training
- Being able to standardize a process for optimal efficiency, repetition, and use
- To aid the study of efficiency and improvement in a process, highlight areas of inefficiency, bottlenecks, and unnecessary steps in a diagram
- To model a new or improved process
- To communicate and collaborate on a number of projects
Process Flow Diagram Equipment Symbols
Flow chart symbols use different shapes to represent different components, such as equipment, valves, instruments, and piping flow. There is a standardized set of flowchart symbols.
Process Flow Diagram equipment symbols include centrifuges and heat exchangers.
Centrifuges
Centrifuges are devices that use centrifugal force/ acceleration to separate components of a mixture on the bases of their density, size, viscosity, and rotor speed. The more dense molecules move to the outside of the centrifuge and the less dense molecules move towards the centre.
CENTRIFUGAL COMPRESSOR 1
CENTRIFUGAL COMPRESSOR 2
CENTRIFUGAL COMPRESSOR 3
CENTRIFUGAL FAN
CENTRIFUGAL PUMP 0
CENTRIFUGAL PUMP 2
CENTRIFUGAL PUMP 3
CENTRIFUGAL PUMP 4
CENTRIFUGAL PUMP 5
CENTRIFUGAL PUMP
CENTRIFUGAL PUMPCENTRIFUGAL PUMP
CENTRIFUGE BLOWER
CENTRIFUGE SCREW, PERFORATED SHELL
CENTRIFUGE SCREW
CENTRIFUGE, PERFORATED SHELL
CENTRIFUGE BLOWER
CENTRIFUGE, PUSHER
CENTRIFUGE, SEPARATOR DISC
CENTRIFUGE, SKIMMER
CENTRIFUGE, SOLID SHELL
Heat Exchangers
Heat exchangers are a system that transfers heat between 2 or more fluids, separated by a solid wall. Heat exchangers can be used for both cooling and heating processes.
AIR-BLOWN COOLER
BOILER
BRIQUETTING MACHINE
COIL TUBES HEAT EXCHANGER
COMBUSTING CHAMBER
CONDENSER
CONDENSER 1
COOLER
COOLER TOWER 1
COOLING TOWER 2
COOLING TOWER 3
DOUBLE PIPE HEAT EXCHANGER
ELECTRIC HEATER
EXCHANGER
EXTRACTOR HOOD
FAN-FAN COOLER
FINNED TUBES HEAT EXCHANGER
FIRED HEATER
FLOATING HEAD HEAT EXCHANGER
FORCED-DRAFT COOLING TOWER
HEAT EXCHANGER
HEAT EXCHANGER 3
HEATER
HOSE REEL
INDUCED FLOW AIR COOLER
INDUCED-DRAFT COOLING TOWER
KETTLE HEAT EXCHANGER
LIGHT WATER STATION
OIL BUMER
PLATE HEAT EXCHANGER
REBOILER
REBOILER HEAT EXCHANGER
SHELL AND TUBE HEAT 1
SHELL AND TUBE HEAT 2
SHELL AND TUBE HEAT 3
SHELL AND TUBE HEAT 3
SINGLE PASS HEAT EXCHANGER
SPIRAL HEAT EXCHANGER 1
SPIRAL HEAT EXCHANGER 2
SPRAY COOLER
STRAIGHT TUBES HEAT EXCHANGER
THIN-FILM EVAPORATOR
U-TUBE HEAT EXCHANGER
U-TUBE HEAT EXCHANGER 2
VENT
VERTICAL TURBINE
Miscellaneous PFD Symbols
Crushers
Crushers are used to reduce the size of or change the form of materials, often for waste, to be deposited or recycled. They reduce the size of a solid mix of raw material.
COARSE CRUSHER
CONE CRUSHER
CRUSHERS
HAMMER CRUSHER
HAMMER CRUSHERS
IMPACT CRUSHER
JAW CRUSHER
MEDIUM CRUSHERS
ROLLER CRUSHER
VARIOUS CRUSHERS
JAW CRUSHER
Dryers
DRYER
DRYING OVEN
FLUIDIZED BED DRYER
FLUIDIZED BED DRYER
HEAT CONSUMER
MOTOR GENERATOR
MOVING SELF DRYER
ROLLER CONVEYOR BELT DRYER
SPRAY DRYER
General PFD Symbols
ALKYATION
AUTOMATIC STOKER
BOOM LOADER
CHIMNEY TOWER HYPERBOLIC
COUNTERFLOW FORCED DRAFT
CROSSFLOW INDUCTED DRAFT
ELECTRIC MOTOR
FLUID CATALYTIC CRACKING
FLUID CRACKING
FLUIDIZED REACTOR
FURNACE
FURNACE 1
HYDROCRACKING
HYDROCRACKING 1
HYDROSULFURIZATION
PACKED TOWER
PLATE TOWER
SCREEN
TRANSPORT
TUBULAR
Mixers Symbols
ANCHOR AGITATOR
CROSS-BEAM AGITATOR
DISC AGITATOR
GAT PADDLE AGITATOR
HELICAL AGITATOR
IMPELLER AGITATOR
IN-LINE MIXER
MIXER
PROPELLER AGITATOR
STIRRER AGITATOR
TURBINE AGITATOR
VARIOUS MIXER
VARIOUS MIXER 2
VARIOUS MIXERS
Peripheral PFD Symbols
AERATOR WITH SPARGER
BACKDRAFT DAMPER
BAG FILLING MACHINE
BELT SKIMMER
BOX TRUCK
BUCKET ELEVATOR
CHIMNEY
CONVEYOR
CONVEYOR 1
CONVEYOR, CHAIN, CLOSED
CONVEYOR, SCREW, CLOSED
CONVEYOR, VIBRATING, CLOSED
CRANE
CYCLONE
CYCLONE SEPARATOR
CYLINDER PISTON
ELECTROMAGNETIC PRECIPITATOR SEPARATOR
ELECTROMAGNETIC SEPARATOR
ELEVATOR
ELEVATOR 1
ELEVATOR 2
FIRING SYSTEM
FLAME ARRESTOR
GAS FLARE
GRAVITY SEPARATOR
HOISTS
HORIZONTAL SHAPING MACHINE
IMPACT SEPARATOR
INDUSTRIAL TRUCK
INJECTOR
LIFT
MANUAL FORKLIFT
OVERHEAD CONVEYOR
PALLETIZER
PELLETIZING DISC
PERMANENT MAGNET
PISTON EXTRUDER SHAPING MACHINES
PROPORTIONAL FEEDER
REDUCER
ROLLER CONVEYOR
ROLLER PRESS
ROLLING BIN TRUCK
ROTARY TABLE FEEDER
ROTARY VALVE FEEDER
RUPTURE DISC
SCRAPER CONVEYOR
SCREENING
SCREW CONVEYOR
SCREW EXTRUDER SHAPING MACHINES
SHIP
SKIP HOIST
SOLIDIFIER
SPRAY NOZZLE
TRUCK FORKLIFT
VIEWING GLASS WITH LIGHTING
VIEWING GLASS
Z-FORM ELEVATOR
Piping Fittings
Piping fittings are adaptors used to connect straight sections of pipe or tube in a pipe system to create the required geometry.
EXHAUST HEAD
STRAINER
TRIANGLE SEPARATOR
TRIANGLE SEPARATOR 2
FAQ - System Integration
What is a Process Flow Diagram?
A process flow diagram is a flowchart that depicts the relationships between major components in a process or circuit. The concept originated in 1921 – it was designed by industrial engineer Frank Gilbreth. Today the concept is often used in industrial plants for chemical and process engineering but the concepts can also be applied to a number of other applications.
Process flow diagrams consist of a series of flowchart symbols and notations to illustrate a process. The different types of flowcharts can vary hugely from hand-drawn flowcharts to complex software flowcharts.
What's Included in a Process Flow Diagram?
- Process piping
- Major equipment items
- Operational data (pressure, temperature, etc.)
- Major bypass
- Process stream names
- Pipe classes and line numbers
- Minor bypass lines
- Instrumental details
- Instrumentation
- Isolation and shut off valves
- Controllers (such as a flow controller)
- Maintenance vents and drains
- Flanges
- Relief and safety valves
What is a Process Flow Diagram Used for?
- Process Flow Chart
- Flowsheet
- Plumbing & Instrumental Diagram
- Macro Flowchart
- Top-Down Flowchart
- Block Flow Diagram
- Schematic Flow Diagram
- System Flow Diagram
- System Diagram
What is the Process Symbol in a Flowchart?
How to Create a Process Flow Diagram
Here are 6 steps to create a process flow diagram:
- Define the scope of the system, what will it achieve?
- Determine the process boundaries, what causes it to start? Where does it end? What are the boundaries of the process?
- Identify the process outputs, what is the final goal?
- Identify the inputs, are there any manual inputs? What is required at each step?
- Use this data to create a model, add necessary detail such as control points and measurements. Think methodically how do components interact with one another.
- Add process symbols to describe the component/ equipment.
- Create a data dictionary, outlining data omitted from the flowchart.
- Review, revise, and test when necessary.
What are Process Flow Diagram Standards?
- ISO 15519-1:2010(en): Specification for diagrams for the process industry — Part 1: General rules
- ISO 15519-2:2015(en): Specifications for diagrams for the process industry — Part 2: Measurement and control
- ISO 10628-1:2014(en): Diagrams for the chemical and petrochemical industry — Part 1: Specification of diagrams
- ISO 10628-2:2012(en): Diagrams for the chemical and petrochemical industry — Part 2: Graphical symbols
What Are Basic Flowchart Symbols?
For software-based process flow diagrams, there are a number of basic symbols to identify. These include:
- Oval – input/ output of the system
- Rectangle – a step in the process
- Arrows/ lines – indicate directional flow
- Diamond – represents a decision
These symbols are not commonly used in engineering diagrams such as mechanical, chemical, and electrical process flow diagrams. These symbols, however, can be found in computer software.