process diagrams design

Process Diagrams

OBJECTIVESAfter studying this chapter, the student will be able to:

• Review process diagram symbols.

• Describe the use of process diagrams and the information they contain.

• Draw a process flow diagram.

• Draw a process and instrument drawing.

• Describe the various process equipment relationships.

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Key TermsElectrical drawings—symbols and diagrams that depict an electrical process.

Elevation drawings—a graphical representation that shows the location of process equipment inrelation to existing structures and ground level.

Equipment location drawings—show the exact floor plan for location of equipment in relation tothe plan’s physical boundaries.

Flow diagram—a simplified sketch that uses symbols to identify instruments and vessels and todescribe the primary flow path through a unit.

Foundation drawings—concrete, wire mesh, and steel specifications that identify width, depth,and thickness of footings, support beams, and foundation.

Legends—a document used to define symbols, abbreviations, prefixes, and specialized equipment.

Process and instrument drawing (P&ID)—a complex diagram that uses process symbols todescribe a process unit; also called piping and instrumentation drawing.

Chapter 12 ● Process Diagrams

252

Types of Process Diagrams

Process diagrams can be broken down into two major categories: processflow diagrams (PFDs) and process and instrument drawings (P&IDs),sometimes called piping and instrumentation drawings. A flow diagram is asimple illustration that uses process symbols to describe the primary flowpath through a unit. A process flow diagram provides a quick snapshot ofthe operating unit. Flow diagrams include all primary equipment and flows.A technician can use this document to trace the primary flow of chemicalsthrough the unit. Secondary or minor flows are not included. Complex con-trol loops and instrumentation are not included. The flow diagram is usedfor visitor information and new employee training.

A process and instrument drawing is more complex. The P&ID includes agraphic representation of the equipment, piping, and instrumentation. Mod-ern process control can be clearly inserted into the drawing to provide aprocess technician with a complete picture of electronic and instrumentsystems. Process operators can look at their process and see how the en-gineering department has automated the unit. Pressure, temperature, flow,and level control loops are all included on the unit P&ID.

Basic Instrument Symbols

Process technicians use P&IDs to identify all of the equipment, instru-ments, and piping found in their units. New technicians use these drawings

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Basic Instrument Symbols

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GlobeValve

GateValve

Reboiler

Three-WayValve

Check Valve

Shell & Tube Heat Exchanger

BleederValves

PneumaticOperated

CentrifugalPumps

RotaryCompressor

ManualOperated

Valve

Gauge

VacuumPumpReciprocating

Compressor

Turbine

Orifice

PneumaticOperated

Butterfly Valve

Compressor &Silencers

Single PassHeat Exchanger

U-TubeHeat Exchanger

SafetyPSV

Butterfly

Ball

SolenoidValve

CLOSED

S

VALVES

PUMPS & TURBINECOMPRESSORS

HEAT EXCHANGERS

Bin

Tank

Tower

Drum or Condenser

Mixer

Mixing Reactor

Minor Process

Pneumatic

Hydraulic

Capillary Tubing

Electromagnetic Signal

Electric

X X X X XX

L L L

VESSELS

Furnace

Liquid RingCompressor

Hairpin Exchanger

CondenserHeater

Centrifugal Compressor

Towerwith Packing

Centrifugal Compressor(Turbine Driven)

T

Gear Pump

Vertical

Screw Pump

Rotameter

Four-WayNeedle Angle

LINE SYMBOLS

Major Process

Future Equipment

Plug

Diaphragm

M

H

Hydraulic BackPressureRegulator

BackPressureRegulator

MotorReliefPRV

Induced-Draft Cooling Tower

Forced-Draft Cooling Tower Flow Indicator

Flow Transmitter

Flow Recorder

Pressure Indicator

Pressure Transmitter

Pressure Recording Controller

FI

FT

FR

PI

PT

PRC

Temp Indicator

Temp Transmitter

Temp Recorder

Level Indicator

Level Transmitter

Level Controller

TI

TT

TR

LI

LT

LC

Figure 12.1a Process and Instrument Symbols

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during their initial training period. Knowing and recognizing these symbolsis important for a new technician.The chemical processing industry has as-signed a symbol for each type of valve, pump, compressor, steam turbine,heat exchanger, cooling tower, basic instrumentation, reactor, distillationcolumn, furnace, and boiler (Figure 12.1). There are symbols to representmajor and minor process lines and pneumatic, hydraulic, or electric lines,and there is a wide variety of electrical symbols.

Flow Diagrams

New technicians are required to study a simple flow diagram of their as-signed operating system. Process flow diagrams typically include the majorequipment and piping path the process takes through the unit. As operatorslearn more about symbols and diagrams, they graduate to the much morecomplex P&IDs.


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Flow Indicator

Flow Transmitter

Flow Recorder

Pressure Indicator


FI

FT

FR

PI

PT

Temp Indicator

Temp Transmitter

Temp Recorder

Level Indicator

Level Transmitter

Level Controller

TI

TT

TR

LI

LT

LC

F I C

55

Variable BeingMeasured

Remote Location(board mounted)Control Loop

Instrument

Remote Location(behind control panel)

Field Mounted

LR Level Recorder

TC Temp Controller

PR Pressure Recorder

Pressure ControllerPC

65 55

5565

65 55

Flow ControllerFC

PIC

PRC

LA

105

40

25

IP

Transducer

Pressure IndicatingController

Pressure RecordingController

Level Alarm

FE Flow Element

TE Temperature Element

LG Level Gauge

AT Analyzer Transmitter

What It Does

Figure 12.1b Process and Instrument Symbols (continued)

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Some symbols are common among plants; others differ from plant to plant.Some standardization of process symbols and diagrams is taking place.The symbols used in this chapter reflect a wide variety of petrochemicaland refinery operations.

Figure 12.2 is a PFD that shows the basic relationships and flow pathsfound in a process unit. It is easier to understand a simple flow diagram if itis broken down into sections: feed, preheating, the process, and the finalproducts. This simple left-to-right approach allows a technician to identifywhere the process starts and where it will eventually end. The feed sectionincludes the feed tanks, mixers, piping, and valves. In the second step, theprocess flow is gradually heated for processing. This section includes heatexchangers and furnaces. In the third section, the process is included. Typ-ical examples found in the process section could include distillationcolumns or reactors.The process area is a complex collection of equipmentthat works together to produce products that will be sent to the final section.

Flow Diagrams

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Furnace

Feed Tank

Bottoms Tank

Boiler

Cooling Tower

Reactors

ProductTank

2

ProductTank

1

Vacuum Pump

Column

Drum

Figure 12.2 Process Flow Diagram (PFD)

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Process and Instrument Drawings

A P&ID is a complex representation of the various units found in a plant(Figure 12.3). It is used by people in a variety of crafts. The primary usersof the document after plant startup are process technicians and instrumentand electrical, mechanical, safety, and engineering personnel.

In order to read a P&ID, the technician needs an understanding of theequipment, instrumentation, and technology. The next step in using a P&IDis to memorize your plant’s process symbol list. This information can befound on the process legend. Process and instrument drawings have a va-riety of elements, including flow diagrams, equipment locations, elevationplans, electrical layouts, loop diagrams, title blocks and legends, and foun-dation drawings. The entire P&ID provides a three-dimensional look at thevarious operating units in a plant.

Process LegendThe process legend (Figure 12.4) provides the information needed to inter-pret and read the P&ID. Process legends are found at the front of the P&ID.The legend includes information about piping, instrument and equipment


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F-105

Tk-10

Tk-16

B-105

CT-105

Rx-105C-105

FCV

I/P

TT TC

I/P

PT

PC

PCV

I/P

LT

LC

I/P

I/PLT LC

TE TT TC I/P

P-10

P-11

Rx-106

P-12

V-1

D-105

Tk-12

Tk-14

P-13

P-14

V-2 V-3

V-4

V-5

V-6

EX-105

V-7

P-15

FT

FC

Figure 12.3 Process and Instrument Diagram (P&ID)

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GlobeValve

GateValve

Three-WayValve

BleederValves

ManualOperated

Valve

Gauge

Orifice

SAFETY (Gases)

Ball

Solenoid ValveCLOSED

S

Rotameter

Four-Way

Angle Plug

Diaphragm

Butterfly

CheckValve

ReliefValve

Pneumatic

Pneumatic

Pinch Valve

Stop Check

Knife Valve INDUCED DRAFTCrossflow

NATURAL DRAFTCounterflow

FURNACE

BOILER

VacuumPump

Centrifugal

Drum

GearPump Positive

Displacement

Dome RoofTank

Sphere

Rotary ScrewCompressor

Progressive Cavity

Screw Pump

ReciprocatingPump

Sump Pump

Horizontal

Vertical

Internal FloatingRoof Tank

Cone RoofTank

Plate and FrameHeat Exchanger

Air Cooled Exchanger(Louvers Optional)

Double-PipeHeat Exchanger

CC

Spiral Heat Exchanger

Condenser

Heater

SinglePass

Chimney

Two Pass

Draw Off

GenericTray

Demister

SprayNozzle

PackedSection

Manway

VortexBreaker

VALVE SYMBOLS

EQUIPMENT SYMBOLS

Minor Process

Pneumatic

Hydraulic

Capillary Tubing

Electromagnetic, SonicOptical, Nuclear

X X X X

L L L

Major ProcessFuture Equipment

Connecting Line

Non-Connecting Line

Non-Connecting Line

Jacketed or Double Containment

Mechanical Link

Software or Data Link

• • • •

Electric

Flow Indicator

Flow Transmitter

Flow Recorder

Pressure Indicator


FI

FT

FR

PI

PT

Temp. Indicator

Temp. Transmitter

Temp. Recorder

Level Indicator

Level Transmitter

Level Controller

TI

TT

TR

LI

LT

LC

LR Level Recorder

TC Temp. Controller

PR Pressure Recorder

Pressure ControllerPC

65 55

5565

65 55

Flow ControllerFC

PIC

PRC

LA

105

40

25

IP

Transducer

Pressure IndicatingController

Pressure RecordingController

Level Alarm

FE Flow Element

TE Temperature Element

LG Level Gauge

AT Analyzer Transmitter

APPROVED

GENERAL LEGEND

DRAWING NUMBER

REVISION 1

PC

E

DATE 10-6-99

PAGE 1 OF 30

OO6543

DISTILLATION UNIT

LINE SYMBOLSEQUIPMENT CONT.

INSTRUMENT SYMBOLS

PREFIXES ABBREVIATIONSCW- cooling waterMU- makeupFW- feed waterSE- sewer

RX- reactorUT- utilitiesCA- chemical additionIA- instrument air

D- drumC- columnCT- cooling tower

TK-tankF- furnaceEX- exchanger

P- pumpV- valve

Figure 12.4 Process Legend

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symbols, abbreviations, unit name, drawing number, revision number,approvals, and company prefixes. Because symbol and diagram standard-ization is not complete, many companies use their own symbols in unitdrawings. Unique and unusual equipment will also require a modified sym-bols file.

Foundation DrawingThe construction crew pouring the footers, beams, and foundation usesfoundation drawings (Figure 12.5). Concrete and steel specifications aredesigned to support equipment, integrate underground piping, and providesupport for exterior and interior walls. Process technicians do not typicallyuse foundation drawings, but these drawings are useful when questionsarise about piping that disappears under the ground and when new equip-ment is being added.

Elevation DrawingElevation drawings (Figure 12.6) show the location of process equipmentin relation to existing structures and ground level. In a multistory structure,the elevation drawing provides the technician with information about


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N

WE

S

64' 0"

28' 0"

28' 0"

6' 0"

8' 0"

10' 0"

6-8-10 Method

2' x 64' x 18"Load-Bearing

Beam

18"4"

12"

Estimating Materials: cu. yds. = width x length x thickness

27

Remesh RemeshOver Plastic

Remesh

Rebar in All Beams

32' 0"

90

Figure 12.5 Foundation

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equipment location.This information is important for making rounds, check-ing equipment, developing checklists, catching samples, and performingstartups and shutdowns.

Electrical DrawingElectrical drawings (Figure 12.7) include symbols and diagrams that de-pict an electrical system. Electrical drawings show unit electricians wherepower transmission lines run and places where power is stepped down orup for operational purposes.

A process technician typically traces power to the unit from a motor controlcenter (MCC). The primary components of an electrical system are theMCC, motors, transformers, breakers, fuses, switchgears, starters, andswitches. Specific safety rules are attached to the operation of electricalsystems. The primary safety system is the isolation of hazardous energy“lock-out, tag-out.” Process technicians are required to have training in thisarea. Figure 12.7 shows the basic symbols and flow path associated withan electrical drawing. Electrical lines are typically run in cable trays toswitches, motors, ammeters, substations, and control rooms.

A transformer is a device used by industry to convert high voltage to lowvoltage. The electric department always handles problems with transform-ers. Electric breakers are designed to interrupt current flow if design condi-tions are exceeded. Breakers are not switches and should not be turned on


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EL 16' 0"

EL28' 0"

EL-40' 0"

TK-105

RX-105

TK-200

TK-300

RX-106

RX-300 C-300

D-56

Figure 12.6Elevation Drawing

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V Voltmeter: measures voltage Vs Voltmeter Switch

27

Power Transformer: reduces high voltage

Potential Transforming Symbol

Under Voltage Relay

M Motor MCC Motor Control Center

Switch

Fuse

Circuit Breaker: a protective devicethat interrupts current flow through anelectric circuit

A

As

50

51

Ammeter: measures electric current Ammeter switch

Transformer Overcurrent Relay (Instantaneous)

Transformer Overcurrent Relay (Time delay)

Motor Circuit Contacts

Current Transformer: reduces high voltage to instrumentation.

BOILERSteamTurbine

Generator

69,000 Volts

69 KV

13,200 V13, 800 V2,300 V

13.2 KV13.8 KV2.3 KV

OnOff

Motor

2.3 KV or480 Volts

51

MAINTRANSFORMER

As

A

27

V

Vs

MCC #1

480V BUS MAIN POWER DISTRIBUTION

ELECTRIC POWER PLANT

M M

MotorStarter

MotorStarter

Figure 12.7 Electrical Drawing

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or off. If a tripping problem occurs, the technician should call for an electri-cian. Fuses are devices designed to protect equipment from excess cur-rent. A thin strip of metal will melt if design specifications are exceeded.During operational rounds, technicians check the ammeters inside theMCC for current flow to their electrical systems. Voltmeters, electricaldevices used to monitor voltage in an electrical system, are also checkedduring routine rounds.

Equipment Location DrawingEquipment location drawings (plot plans) show the exact location ofequipment in relation to the plant’s physical boundaries (Figure 12.8). Oneof the most difficult concepts to explain to a new process technician is thescope and size of modern chemical processing. Most chemical plants andrefineries closely resemble small cities; they have well-defined blocks andareas connected by a highway of piping and equipment. Equipment loca-tion drawings provide information about the neighborhood.

Loop DiagramsA loop diagram traces all instrument connections between the field instru-ment and the control room panel. This includes instrument air lines, wiringconnections at field junction boxes, and control room panels and frontconnections.

Electrical One-Line DiagramsLike the piping in process systems, the wiring in a unit follows a path. Electri-cal diagrams show a flow path for distributing power throughout the unit and


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TK-100TK-100

P-100P-200

P-300P-400

D-200

P-500A

EX-200

EX-202

TK-1 TK-2

TK-3 TK-4

TK-1 TK-2

TK-3 TK-4

P-201

20' 0"

10' 0

"

20' 0

"

18' 0" 8' 0"

20' 0

"

8' 0

"

6' 0

"

18' 0"

8' 0"

16' 0"

20' 0"

C-200C-200

TK-200TK-200

TK-400TK-400TK-300TK-300

Figure 12.8Equipment Location

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to all electrical equipment. These diagrams show the different voltage levelsin the unit, electrical equipment such as transformers, circuit breakers, fuses,and motors and horsepower required. It also includes start/stop switches,emergency circuits, and motor control centers. Process technicians can usethese diagrams to trace a system from the power source to the load.

Review of Basic and Specialized Symbols

Piping and ValvesEach plant will have a standardized file for their piping symbols. Processtechnicians should carefully review the piping symbols for major and minorflows; electric, pneumatic, capillary, and hydraulic elements; and futureequipment (Figure 12.9). The major flow path through a unit illustrates the


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Y-type Strainer

Duplex Strainer

Basket Strainer

D Detonation Arrestor

F Flame Arrestor

T Steam Trap

S In-Line Silencer

DS Desuperheater

Ejector / Eductor

Exhaust Head

S Vent Silencer

RSRemovable Spool

Flexible Hose

Expansion Joint

XXX Breather

Vent Cover

In-Line Mixer

Diverter Valve

Rotary Valve

Pulsation Dampener

Flange

Minor Process

Pneumatic

Hydraulic

Capillary Tubing

Electromagnetic, SonicOptical, Nuclear

X X X X

L L L

Major Process

Future Equipment

Connecting Line

Non-Connecting Line

Non-Connecting Line

Jacketed or Double Containment

Mechanical Link Software or Data Link• • • •

Electric

Figure 12.9Piping Symbols

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critical areas a new technician should concentrate on. A variety of othersymbols are included on the piping. These include valves (Figure 12.10),strainers, filters, flanges, spool pieces, insulation, piping size, pressure rat-ing, material codes, and steam traps.

Pumps and TanksPumps and tanks come in a variety of designs and shapes. Common pumpand tank symbols are shown on Figure 12.11.

Compressors, Steam Turbines, and MotorsBecause compressors and pumps share a common set of operating prin-ciples and are classified as dynamic or positive displacement, the sym-bols for compressors may closely resemble those for pumps (compare


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GlobeValve

GateValve

Three-WayValve

BleederValves

PneumaticOperated

ManualOperated

Valve

Gauge Orifice

SAFETY (Gases)

Butterfly

Ball

Solenoid ValveCLOSED

S

Rotameter

Four-Way

Needle

Angle

Plug

Diaphragm

Butterfly Butterfly

CheckValve

CheckValve

ReliefValve

M

Pneumatic Motor Hydraulic

M H

M H M

Ball

H M

Pneumatic Motor HydraulicMotor

Motor orHydraulic

Pneumatic

Motor

M

GATE VALVES

GLOBE VALVES

BALL VALVES

BUTTERFLY VALVES

DIAPHRAGM VALVES CHECK VALVES

PLUG VALVES

Motor orHydraulic

Motor orHydraulic

Plug

Pinch Valve

Stop Check

Knife Valve

RELIEF (Liquids)

Figure 12.10Valves

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Figures 12.11 and 12.12). In most cases, the compressor symbol is slightlylarger than the pump symbol.

In the multistage, centrifugal compressors, the narrowing of the symbol fromleft to right denotes compression of the gas before it is released. This is insharp contrast to the steam turbine symbol, which illustrates the opposite ef-fect as the steam expands while passing over the rotor. Modern P&IDs showthe motor symbol connected to the driven equipment. This equipment maybe a pump, compressor, mixer, or generator. Figure 12.12 illustrates thestandardized symbols for compressors, steam turbines, and motors.

Heat Exchangers and Cooling TowersHeat exchangers and cooling towers are two types of industrial equipmentthat share a unique relationship. A heat exchanger is a device used to


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Vacuum Pump

CENTRIFUGAL PUMPS

Bin Tank

Drum

GearPump

Vertical

Screw Pump

POSITIVE DISPLACEMENT PUMPS

Positive Displacement

Dome RoofTank

Open TopTank

Tank

Sphere Onion Tank

STORAGE SYMBOLS

Progressive Cavity

PositiveDisplacement

Screw Pump

Vertical CanPump

Reciprocating Pump

Sump Pump

Horizontal

Vertical

Vertical

Internal FloatingRoof Tank

Cone RoofTank

Double WallTank

External FloatingRoof

Figure 12.11 Pumps and Tanks

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transfer heat energy between two process flows. The cooling tower per-forms a similar function, but cooling towers and heat exchangers use dif-ferent scientific principles to operate. Heat exchangers transfer heat energythrough conductive and convective heat transfer, whereas cooling towerstransfer heat energy to the outside air through the principle of evaporation.Figures 12.13 and 12.14 illustrate the standard symbols used for heatexchangers and cooling towers.

The symbol for a heat exchanger clearly illustrates the flows throughthe device. It is important for a process technician to be able to recog-nize the shell inlet and outlet and the tube inlet and outlet flow paths. Aheat exchanger with an arrow drawn through the body illustrateswhether the tubeside flow is being used to heat or cool the shellsidefluid. The downward direction indicates heating; the upward direction il-lustrates cooling.


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Figure 12.12 Compressors, Steam Turbines, and Motors

STEAM TURBINE

Doubleflow Turbine

RotaryCompressor

ReciprocatingCompressor Rotory

Compressor & Silencers

CENTRIFUGAL COMPRESSORS

Centrifugal Compressor

Centrifugal Compressor(Turbine Driven)

PD COMPRESSORS

Rotary ScrewCompressor

PositiveDisplacement

Blower

Liquid RingVacuumCentrifugal

Blower

CentrifugalCompressor

Reciprocating Compressor

Motor

MOTORS

Turbine Driver

Diesel Motor

Agitator or Mixer

Axial Compressor

T

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Plate and FrameHeat Exchanger

Air Cooled Exchanger(Louvers Optional)

Double-PipeHeat Exchanger

CC

Spiral Heat Exchanger

Shell and Tube Heat Exchanger

Single PassHeat Exchanger

U-TubeHeat Exchanger

Hairpin Exchanger

CondenserHeater

Reboiler

Figure 12.13Heat Exchangers

INDUCED DRAFTCrossflow FORCED DRAFT

Counterflow

HYPERBOLICChimney Tower

NATURAL DRAFTCounterflow

Figure 12.14Cooling Towers

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The symbol for a cooling tower is designed to resemble the actual devicein the process unit. Cooled product flows out of the bottom of the tower andto the processing units. Hot water returns to a point located above the fill.The symbol will not show all of the various components of the cooling towersystem, but it will provide a technician with a good foundation in coolingtower operation and enough information to clearly see the process.

Furnaces and BoilersThe standard symbols file for furnaces and boilers is shown in Fig-ure 12.15. If a proprietary process includes several types of equipment nottypically found on a standard symbol file, the designer will draw the deviceas it visually appears in the unit.

Distillation ColumnsDistillation columns come in two basic designs, plate and packed (Fig-ure 12.16). Flow arrangements vary from process to process. The sym-bols allow the technician to identify primary and secondary flow paths.Distillation is a process designed to separate the various components ina mixture by their boiling points. (See Chapter 15.) A distillation column isthe central component of a much larger system. This system typically in-cludes all of the equipment symbols found in this chapter. Plate distillationcolumns include sieve trays, valve trays, and bubble-cap trays. Packedcolumns are filled with packing material, rings, saddles, sulzer, androsette.

ReactorsReactors (Figure 12.17) are stationary vessels and can be classified asbatch, semibatch, or continuous. A reactor is designed to allow chemi-cals to mix together under specific conditions to make chemical bonds,break chemical bonds, or make and break chemical bonds to form newproducts.


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Furnace Boiler

Figure 12.15Furnace and Boiler

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Sources of Informationfor Process Technicians

Information used by process technicians comes from a variety of sources.Some of these sources are:

• Operating training manuals• Process descriptions• Process control manuals• Equipment summaries• Safety, health, and environment regulations• Operating procedures• Startup and shutdown procedures


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PLATE TOWERBubble-cap, Sieve, Valve

PACKED TOWERSaddle, Ring, Sulzer, Rosette

Single Pass

Chimney

Two Pass

Draw Off

Generic Tray

Demister

Spray Nozzle

Packed Section

Manway

Vortex Breaker

Figure 12.16Distillation Symbols

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• Emergency procedures• Process diagrams• Technical data books• Detailed equipment vendor information

Summary

Process flow diagrams (PFDs) and process and instrument drawings(P&IDs) are used to outline or explain the complex flows, equipment, in-strumentation, electronics, elevations, and foundations that exist in aprocess unit. A PFD is a simple flow diagram that describes the primaryflow path through a unit. A P&ID is a complex representation of the variousunits found in a plant. Standardized symbols and diagrams have beendeveloped for most pieces of industrial equipment, process flows, andinstrumentation.

Summary

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Hydrocracking Hydrodesulfurization Reformer

Fluid CatalyticCracking

Fluid Coking TubularReactor

FluidizedReactor

Mixing Reactor Alkylation

Figure 12.17Reactor Symbols

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Review Questions1. Describe a process flow diagram and a process and instrument drawing.

2. Draw the symbols for a gate, globe, and automatic valve.

3. Draw the symbols for a centrifugal pump and positive displacement pump.

4. Draw the symbols for a blower and a reciprocating compressor.

5. Draw the symbols for a steam turbine and centrifugal compressor.

6. Draw the symbols for a heat exchanger and a cooling tower.

7. Draw the symbols for a packed distillation column and plate distillation column.

8. Draw the symbols for a furnace and a boiler.

9. Draw a simple process flow diagram using the symbols from questions 2–8.

10. What information is obtained from a loop diagram?

11. What information is available on electrical one-line diagrams?

12. What information is contained on a plot plan drawing?

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process diagrams design

Design