The document discusses tag numbering systems used in oil, gas, and petrochemical plants. It explains that every component and piece of equipment requires a unique identification tag for safety and maintenance purposes. While there is no single standard, companies follow common conventions and best practices. Tag numbers are applied during design and construction, and are used on equipment, drawings, manuals, and computer systems for life. Examples of tag numbering processes and standards are provided.

1. Tag numbering system in oil, gas and
petrochemical industry.
Hundreds of thousands of components and equipment are installed in each
OGP plant and require unique identification (ID) to be easily and safely
identified during operation, maintenance, function testing, inspection or
troubleshooting. There is a need to have a unified tag numbering system or
coding system to assign every component and equipment a unique ID.
Assigning IDs starts in project design phase and shall follow some guidelines
or standard. Unfortunately there is no single standard or guideline which can
manage all types (mechanical, electrical, instrument, HVAC, safety equipment,
piping and pipelines) of components and equipment. Tag numbering system or
coding system is well defined in project specifications and despite there is no
common single standard or single guideline, there is common convention in
OGP industry based on best practices and relevant standards to form the tag
numbering or coding system specifications. Examples of these practices (in-
house standard) are Shell DEP 01.00.09.10 and Norsok Z-DP-002.
At site, tag numbers shall be clearly written on visible location at equipment,
stamped onto nameplate and metal strips as appropriate, even project
specifications can stipulate the font size and color. The same tag numbers are
used in data sheets, PFDs, PIDs, instrument list, procedures, IOM manuals,
control system, control mimics and CMMS, they are life-time IDs. The following
are real examples of tag numbering process.

2. Tag numbering system specifications
Equipment

3. Driver

4. Auxiliary Equipment

5. NUMBERING OF INSTRUMENTS

6. NUMBERING OF PIPING LINE

7. NUMBERING OF ELECTRICAL EQUIPMENT IN SUBSTATION

8. NUMBERING of Building and HVAC

9. APPENDIX-I FACILITY CODE (FIRST 3 DIGITS OF UNIT CODE)
Code Unit Description Unit Abbreviation
000 General
110 Crude Distillation Unit CDU
120 CDU LPG Merox Process UNIT CDU LPG MEROX
130 CDU Kerosene Merox Process Unit KEROSENE MEROX
200 Resid FCC Reactor Regenerator Section RFCC RXRG
210 Resid FCC Main Fractionation Section RFCC MF
220 Resid FCC Gas Concentration Section RFCC GC
230 Resid FCC Flue gas Section RFCC FG
260 Resid FCC LPG Merox Process Unit RFCC LPG MEROX
270 Propylene Recovery Unit PRU
280 Huels Selective Hydrogenation Process Unit SHP
290 Indirect Alkiration Unit InAlk
320 Distillate Unionfining Process Unit DHDS
330 Hydrogen Generation Unit HGU
340 Sour Water Stripping Unit SWS
350 Amine Regeneration Unit ARU
360 Sulfur Recovery Unit (Train 1) SRU1
365 Sulfur Recovery Unit (Train 2) SRU2
370 Tail Gas Treating Unit TGU
380 Sulfur Granulation & Packing Unit SGU
400 TAME Selective Hydrogenation Unit TSHP
410 TAME Unit TAME
420 Gasoline HDS Unit GHDS
Utilities
500 Utility Facilities Common
510 Power Plant, Electricity and Distribution System ELC
520 Sea Water Intake Station SWI
530 Water System WS
531 Cooling Water System CWS
532 Sea Water Desalination System SWD
534 Potable and Service Water System PSW
540 Steam and Condensate System STM

10. APPENDIX-I FACILITY CODE (FIRST 3 DIGITS OF UNIT CODE)
Code Unit Description Unit Abbreviation
550 Fuel Gas and Natural Gas System FG
560 Instrument Air and Plant Air System IA
570 Nitrogen System N2
580 Chemicals Preparation and Injection Facilities
590 Flushing Oil System FO
Offsites
600 Offsite Common
610 Feedstock and Slop Tankage
620 Product and Component Tankage
630 Truck Loading Facilities
640 Marine Loading Facilities
650 Waste Water Treatment Facilities WWT
690 Flare System FLR
700 Marine
800 Buildings
Refinery Common
900 Refinery Common
910 Fire Fighting System FIR
950 Outside Battery Limit General

11. APPENDIX-II EQUIPMENT SYMBOL LETTER
Symbol Letter Description of Equipment
A Special Check Valve, Coalescer and other Miscellaneous Equipment
B Boiler (Fired)
C Column
DA Deaerator
DG Diesel Engine Generator
DS Desuperheater
E S & T Exchanger, Special Heat Exchanger (Hair Pin, Double Tube, Plate), Air Cooled Exchanger, Electric
Heater and Tank Heater
EJ Expansion Joint
F Fired Heater, Air Preheater and Incinerator
GT Gas Turbine
GTG Gas Turbine Generator
J Ejector and Vent Silencer
K Compressor, Blower and Fan
L Duct
LA Loading Arm
LH Loading Hose
M Mixer
ME Machinery, Packaged Unit, Elevator
P Pump (Centrifugal, Reciprocating, Rotary)
R Reactor
S Filter
SK Stack
SN Sample
ST Steam Turbine
STG Steam Turbine Generator
SV Slide Valve
T Tank (Including Spherical Tank)
V Vessel (Including Pressure Storage Vessels)
WHB Waste Heat Boiler and CO Boiler
X Diverter Valve
Z Pit

12. APPENDIX-III FUNCTIONAL IDENTIFICATION OF INSTRUMENTS
Symbol First Letter Subsequent Letters
Measured Variable Modifier Readout or Passive
Function
Output Function /
Mode
Modifier / Alarm
Mode
A Analysis Alarm
B Burner Flame
C Compensated Control Closed
D Differential
E Voltage (EMF) Sensor (Primary
Element)
F Flow Fraction (Ratio e.t.c.)
G Glass, Gauge
H Hand (Manual) Hand High High
I Current (Electrical) Indicate
J Power Scan
K Time or Schedule Time Rate of Change Control Station
L Level Light Low Low
M Motor Intermediate
N Injection
O Operated Orifice Open
P Pressure, Vacuum Point (Test Conn.)
Q Quantity Integrate, Totalize
R Record
S Speed, Frequency Safety, Shutdown Switch, Selector
T Temperature Transmitter
U Multivariable/ Common Multifunction Multifunction
V Vibration Valve, Damper, Louver
W Weight, Force Well
X Miscellaneous, Status Skin Unclassified
Y Event, State or Presence Relay, Compute,
Convert, Solenoid Valve
Z Position, Driver, Actuator,
Unclassified Final
Control Element

13. APPENDIX-IV SYMBOL LETTER FOR MISC. PIPING COMPONENT
Symbol
Letter
Description Symbol
Letter
Description
ARV Automatic Recirculation Valve MOV Motor Operated Valve
BDV Blow Down Valve RO Restriction Orifice
DT Drain Trap SR Strainer (Conical)
SE Emergency Shower & Eye Wash SRY Strainer (Y-Type)
EXH Exhaust Head SRT Strainer (T-Type)
FE Flow Element, such as Orifice Plate SRBLM Strainer (Bucket Type)In Line Mixer
FMT Flexible Metal Tube ST Steam Trap Needle Valve
FA Flame Arrestor SGMOV Sight Glass Motor Operated Valve
HC Hose Connector
IJP Injection Nozzle NV Needle Valve
IGK Insulation Gasket Kits
IF Insulation Flange, Gasket or Kits

14. APPENDIX-IV SYMBOL LETTER FOR MISC. PIPING COMPONENT
TAG DESCRIPTION
18DR Long Radius Elbow (Bending Radius : 18D)
9DR Long Radius Elbow (Bending Radius : 9D)
AV Automatic Vent
CB Cooling Bath
DR Drip Ring
DVT Davit
EXJ Expansion Joint
FPH Finned Pipe (Fin Installation : Circumferential)
FPV Finned Pipe (Fin Installation: Longitudinal)
GAJ Adjustable Type Globe Valve
GMS Globe Valve with Minimum Stopper
HS Hose
HV Gate Valve with Limit Switch
LG Level Gauge
NCV Non Slam Dual Plate Check Valve
PIV Post Indicator Gate Valve
PSC Piston Type Check Valve (Axial Spring Loaded Type)
PVE Plug Valve with Extension Stem
RBJ Rubber Joint
RLF Refractory Lined Fitting
RST Restrut
RV Safety/Relief Valve
SB Spectacle Blind, Blank and Spacer (26” and Larger)
SC Sample Cooler
SLC Silencer
SMV Sampling Valve
SPH Spring Support
SWY Sway Brace
TB Steel Tube
TF Tube Fitting
TSV Twin Seal Type Valve

15. APPENDIX-Ⅴ ELECTRICAL EQUIPMENT SYMBOL LETTER FOR SUBSTATION
Symbol Letter Description
AP Annunciator Panel
AW Aircraft Warning Light Panel
BC Battery Charger
BD Bus Duct
BT Battery
CP Cathodic Protection Transformer Rectifier
DS Disconnecting Switch
ET Earthling Transformer
ER Earthling Resistor
LP Lighting Panel
MC Motor Control Center
PM Power Management System Equipment
PP Power Distribution Panel
RP Receptacle Panel
SW Switchgear
TR Transformer
UP Uninterruptible Power Supply System
WO Welding Outlet

16. APPENDIX-VI SERVICE FLUID IDENTIFICATION SYMBOL
Symbol
Letter
Fluid Symbol
Letter
Fluid
A PROCESS AIR HY HYDROGEN
AC ACID IA INSTRUMENT AIR
AFL ACID FLARE LLS LOW LOW PRESSURE STEAM
AM AMINE LO LUBE OIL
AMD AMINE DRAIN LS LOW PRESSURE STEAM
ARD AROMATICS DRAIN MA METHANOL
AV ATOMOSPHERIC VENT MAD METHANOL DRAIN
BD BLOWDOWN MS MEDIUM PRESSURE STEAM
BFW BOILER FEED WATER N NITROGEN
CA CATALYST NA CAUSTIC
CC COLD CONDENSATE(CLEAN) NG NATURAL GAS
CH CHEMICALS P GENERAL PROCESS
CHW CHILD WATER PA PLANT AIR
CWR SECONDARY COOLING WATER RETURN PW SERVICE WATER (PLANT WATER)
/DESALINATED WATER
CWS SECONDARY COOLING WATER SUPPLY S SULFUR
DMW DEMINIRALIZED WATER SC SUSPECT CONDENSATE
DW POTABLE WATER(DRINKING WATER) SLG SLUDGE
FG FUEL GAS SO SEAL OIL
FL FLARE SWR SEA WATER RETURN
FO FLUSHING OIL SWS SEA WATER SUPPLY
FW FIRE FIGHTING WATER SY SANITARY DRAIN(DOMESTIC EFFLUENT)
HCC HOT CLEAN CONDENSATE TW TEMPERED WATER
HS HIGH PRESSURE STEAM WW WASTE WATER