A process flow diagram (PFD) visually depicts the steps in a process sequentially. It uses simple symbols like rectangles for process steps and arrows to show material and information flow. A PFD for a peanut processing operation is presented as an example. The key steps shown are storing raw peanuts, de-shelling, sorting, and frying. Inputs and outputs at each step are indicated with arrows, such as electricity and coconut oil used for frying. The PFD ends by showing the finished product of fried salted peanuts. Guidelines are provided for continuing a PFD across multiple pages and depicting auxiliary and repeated processes.

1. Drawing a
Process Flow Diagram

2. What is a PFD
• A process flow diagram is a pictorial
representation of what is happening in a
process in a sequential order
• It is a snapshot of the process at the time
of inspection
• It is a paper based tool

3. Why Draw a PFD
• Industries do not know
– What is wasted
– Where is it generated
– How much is wasted

4. PFD for Cleaner Production
A simple diagram which uses only three
main symbols and one auxiliary symbol
Not to be confused with other types of
diagrams

5. Symbols to be Used
Rectangle is used for representing a process
step
Arrow is used to show link and direction
Ellipse represents the beginning and the
end of diagram
A
Circle (with character or sign) is used to
show continuation of a process

6. Tips in drawing a PFD
• List all the process steps prior to drawing PFD
• Break larger steps into simpler steps as much as
possible
• The PFD is drawn from top to bottom of a paper
• Arrows link process steps in sequential order
• Arrows linking process steps must always be
directed downwards (Top to Bottom PFD)
• Labour, Time and Capital equipment not
included as inputs or waste streams
• Inputs should be consumable items/material
only

7. Always Start With an Ellipse
• Draw an ellipse on the top of the page and
• Insert the name of the main raw material
which undergoes the change to form the
final product within it
Raw Peanuts

8. Drawing Process Steps
• Process steps (activities) are
depicted by rectangles
• Rectangles are drawn below
the elipse, one per process
step
• Sequential process steps
(are linked by downward
arrows
• Insert the name of the
process step inside the
rectangle
Storing
Raw Peanuts
De-shelling
Sorting
Frying

9. Indicating Resources Used
• Resources used are
known as INPUTS
• Inputs are indicated on the
left side of the rectangles
(process steps)
• Inward arrows are drawn
from each input material
towards the rectangle
• Inputs are consumable
material used to carry out
the change to the main
raw material at each
process step
Electricity
(Lighting)
LP Gas
Coconut Oil
Hot air
Storing
Raw Peanuts
De-shelling
Sorting
Frying
Electricity
(Lighting)
Electricity
(Lighting)

10. Indicating Waste Streams
• Waste streams are known as OUTPUTS
• Outputs are indicated on the right side
of the rectangle
• Outward arrows are drawn towards
each Output stream from the rectangle
• All waste stream generated at this point
should be indicated on the PFD

11. Shells
Spilt
nuts
Dust
Oil Spills
Nut spills
Oil Evaporation
Waste Heat
Excess gas
Over fried nuts
Storing
Raw Peanuts
De-shelling
Sorting
Frying
LP Gas
Coconut Oil
Hot air
Electricity
(Lighting)
Electricity
(Lighting)
Electricity
(Lighting)
Energy Loss
Foreign Matter
Spilt
nuts Dust

12. How to End the PFD
• The PFD is ended with
an elipse depicting the
finished product
Main Raw material
Finished product
Inputs Outputs

13. Shells
Spilt nuts
Dust
Oil Spills
Nut spills
Oil Evaporation
Waste Heat
Excess gas
Over fried nuts
Storing
Raw Peanuts
De-shelling
Sorting
Frying
LP Gas
Coconut Oil
Hot air
Electricity
(Lighting)
Electricity
(Lighting)
Electricity
(Lighting)
Energy Loss
Foreign Matter
Spilt nuts
Dust
Oil DrainingOil Paper Drained Oil
Used Oil Paper
Salting
Packing
Salt Spilt Salt
Spilt nuts
Packing Material Rejected Packing Material
Spilt Nuts
Overfilled packs
Fried Salted Peanuts

14. Continuation
• If one page is
insufficient to
complete the PFD,
use another.
• Do not try to draw
two PFDs on one
paper.
• Arrows are never
directed upwards
The following method is not correct

15. The following method though correct is
not preferred

16. The following method is correct and preferred
Major Raw Material
A
Page 1
Finished Product
A
Page 2

17. Repeated Processes
Filtering
Mixing
Bagasse
Juice 1
Water
Electrical
Energy
Sugar Cane
Crushing
Juice 2 Juice 3
Electrical
Energy
Filtering
BagasseElectrical
Energy
Mixing
Filtering
BagasseElectrical
Energy
Water
Electrical
Energy

18. Branching
Preparing
Dyeing Printing Bleaching

19. Combining
Dyeing Printing Bleaching
Finishing

20. Auxiliary Processes
• Auxiliary processes are those that support
the main process.
• They include cleaning, Bottle washing,
Steam Generation, Water treatment etc.
• PFD for Auxiliary processes should be
drawn separately and linked to the main
PFD

21. Chemical Spills
Waste
Chemicals
Cleaning
Chemical Washing
Hot water rinsing
First Washing
Bottles
Cleaned Bottles
B
Water
Electricity
(Lighting)
Electricity
(Lighting)
Electricity
(Lighting)
Electricity
(Lighting)
Chemicals
Hot Water
Energy Loss
Energy Loss
Water Spills
Waste Water
Energy Loss
Energy Loss
Hot Water Spills
Waste Water
Boiling
(Boiler)
Fuel
Chemicals
Air
Flue Gas loss
Radiation Heat loss
Steam Leaks
Blow-down loss
Water
Steam
A
Page 2
Mangoes
Washing
Peeling & Cutting
Crushing
Mixing
Page 1
Finished Product
Cooking
Cooling
Bottling
Labelling and Storing
Electricity
(Lighting)
WaterElectricity
(Lighting)
Electricity
Electricity
Steam
Electricity
Sugar
Electricity
Bottles
Electricity
Caps
Electricity
Labels
A
B

22. How to Indicate Cleaning Processes
• Pay attention to processes such as
cleaning operations
– Floor Cleaning
– Machine Cleaning
– Equipment Cleaning
• Such operations should also be indicated
on the PFD

23. This Method is Wrong!
Mangoes
Washing
Peeling & Cutting
Crushing
Mixing
Bottled Mango Juice
Cooking
Cooling
Bottling
Labelling and Storing
Electricity
(Lighting)
WaterElectricity
(Lighting)
Electricity
Electricity
Steam
Electricity
Sugar
Electricity
Bottles
Electricity
Caps
Electricity
Labels
A
B
Water
Detergents

24. How to Indicate Cleaning of the Juice Cooking Pan
Page 1
Mangoes
Washing
Peeling & Cutting
Crushing
Mixing
Bottled Mango Juice
Cooking
Cooling
Bottling
Labelling and Storing
Electricity
(Lighting)
WaterElectricity
(Lighting)
Electricity
Electricity
Steam
Electricity
Sugar
Electricity
Bottles
Electricity
Caps
Electricity
Labels
A
B
C
Page 2
Washing
Electricity
(Lighting)
C Pan Cleaning Process
Detergents
Hot Water
Energy Loss
Waste Water
Water Spills
Detergent Spills

25. PFDs for Services
• The PFD for a service
organization may be
drawn as a block
diagram/Unit Process
• These are prepared for
activities that do not
have sequential steps,
such as Boilers,
Housekeeping activities
in Hotels, Kitchen
activities in Hotels etc.
House keeping
Room
Cleaned Room
Energy
Room cleaning chemicals
Cotton Rags
Toilet cleaning chemicals
Tissue Paper
Toilet paper rolls

26. Use ofUse of
Raw MaterialsRaw Materials
ManufactureManufacture DistributionDistribution UseUse DisposalDisposal
Product Life CycleProduct Life Cycle
For PFDs are not drawn for products
We can draw Life Cycle Diagrams
Can we Draw PFDs for Products?

27. Wording
• All process steps are considered to be
dynamic (process step is taking place at
the time of observation)
• Therefore all steps are referred in present
continuous – Checking
Frying
Dyeing
Drying

28. • Do not Mention the equipment as the
process step
• These terms are wrong
- Dry - Dye - Fry
- Dried - Dyed - Fried
- Dryer - Dying Machine - Frying Pan

29. Additional points
• However small the resource quantity may
be indicate it on the PFD.
• However small the waste stream may be
indicate it on the PFD.
• When considering the process steps the
normal, abnormal, occasional ,accidental
and maintenance operations should also
be taken into account

30. Other Tools

31. Ecomapping - One little picture says more than a long
speech !
• A visual, simple and practical tool to analyse
and manage the environmental performance
of companies industries
• An easy, creative and systematic method of
obtaining environmental data
• An awareness - creation and learning tool
based on the physical reality of the company
• A dynamic inventory of the changes in the
environmental behaviour of the company

32. How to Use Eco-maps
• Indispensable materials
– A4 -sized paper and a photocopy machine.
• Time needed
– Less than one hour of work for each map.
• When to do it?
– After the end of the accounting year.
• How often should they be up-dated ?
– Once a year, or if the site is renovated, or activities are
extended.
• Filing
– With documentation for your environmental
management system, with your annual accounts .
• Who can use them?
– The maps can be used by many different types of
companies: from small manufacturing and service
companies to large structures and local authorities.

33. How to Eco-map
1. Prepare Map of the
urban situation
• Make a map of the site,
seen from above,
including car parks,
access areas, roads
and the surrounding
environment.
• It should show the real
situation.

34. 2. Map of the site
• Draw the outline of the site
using a scale and showing the
interior spaces. This map
should be copied and will be the
basis for the work to be done.
• The maps should show the real
situation - they should be
simple, recognisable and in
proportion. Maps should have a
date, a name and a reference.
Integrate one or two significant
objects such as machines and
boilers, which will enable the
user to orient himself with the
site easily
• If the site covers very different
areas, individual maps of the
different areas can be prepared
and brought together.

35. 3. Symbols
• Develop your own
symbols, but use at least
two Hatched lines: small
problem (area to be
monitored, problem to be
studied)
• Circle: large problem
(stop, corrective action)
• The more serious the
problem, the thicker the
circle

37. Case Study