City Gas Distribution (CGD) networks transport natural gas through interconnected pipelines from transmission mains to distribution grids and service pipes supplying gas to homes and businesses. The Petroleum and Natural Gas Regulatory Board authorizes entities to develop CGD networks in specified geographical areas of India. Technical standards and specifications include safety standards for equipment in CGD networks. The city gate station is where custody of gas transfers from transmission pipelines to the CGD network.

1. What is CGD ?
City Gas Distribution
“City or local natural gas distribution network”
means an interconnected network of gas
pipelines and the associated equipment used
for transporting natural gas from a bulk
supply high pressure transmission main to the
medium pressure distribution grid and
subsequently to the service pipes supplying
natural gas to domestic, industrial or
commercial premises and CNG stations situated
in a specified geographical area;

2. Meter

3. CGD Network authorization
• Under the Petroleum and Natural Gas
Regulatory Board (PNGRB) Act 2006, PNGRB
grants the authorization to the entities for
developing a City Gas Distribution (CGD)
network (including PNG network) in a
specified Geographical Area (GA) of the
country.

4. What is T4S ?
• T4S Means Technical Standards and
Specifications including Safety Standards for
City or Local Natural Gas Distribution
Networks & Natural Gas pipelines.

5. City gate station (CGS)
• The point where custody transfer of natural
gas from natural gas pipeline to the CGD
network takes place and this may also be
referred to as City Gate Measuring and
Pressure Regulating Station.

6. Critical infrastructure / activity/ processes
• Pressure reduction skid CGS (active /monitor combination) with a minimum 50%
redundancy including slam shut valve for over pressure protection and creep relief
valves.
• On line odorisation equipment.
• Height of the vent shall be minimum 3 meters above working level.
• Gas detectors shall be installed at critical locations .
• HSSE Management System.
• Emergency Response Plan, Disaster Management Plan and written emergency
procedures. Also, provide for an Emergency Control Room, manned round the
clock and equipped with effective communication system and emergency vehicles
fitted with communication facilities, first aid equipment, fire extinguishers, gas
detectors, repair kits and tools, maps, plans, material safety data sheets etc.

7. Main Functions
• Isolation
• Filtration
• Pressure reduction.
• Metering.
• Pre Heaters
• PSV & CRV.
• Odorization.

8. Main Functions
• Isolation

9. Filtration
• Filtration

10. Pressure reduction.

11. Metering.
• Metering.

12. Pre Heaters
• Pre Heaters

13. Odorisation
• The odorization process of distributed gases is
required for safety reasons and it acts as a “warning
agent” in case of leakage. The process consists
of injecting a chemical agent — an odorant — that
adds a smell to the gas, turning it easily
recognisable.
• For PNG
• 10 PPM (Part per million)
• 20 milligrams of methyl mercaptan per cubic meter
(mg/m³)
• For LPG
• 25 parts per million (ppm)

14. Valve chain

15. primary network
• pressure above 100 psig (7 bar) and below
711 psig (49 bar)

16. secondary network
• a pressure below 100 psig (7 bar) and above
1.5 psig (100 mbar)
• Also called called low-Pressure Distribution
•

17. tertiary network
• CGD network that operates at pressure less
than 1.5 psig (100 mbar)

18. sub-transmission pipeline
• means a high pressure pipeline connecting the
main transmission pipeline to the city gate
station but is owned by the CGD entity;

19. velocity in the pipeline network
• The Maximum velocity in the pipeline network
should be limited to 100 ft/sec (30 m/sec )
Immediately after pressure regulating
instrument.

20. type of Pipe line
• Steel Pipeline. ( 4” , 8” , 12”……)
• Mdpe Pipe Line ( Medium density Polyethlen
Pipe.
• Size ( 20 mm, 32 mm, 63 mm, 90 mm, 110 mm
,125 mm , 180 mm.

21. MDPE
Medium-density polyethylene (MDPE) is a type of Polyethylene defined
by a density range of (0.926 - 0.940) gm/cm3
Code of MDPE Pipe- IS 14885 .
IS 14885 (2001): Polyethylene Pipes for the Supply of Gaseous Fuels
Colours – yellow – PE 80 grade
Orang – PE 100 grade
# PE100 is a higher density material than PE80 #
Material Designation Minimum Required Strength (MRS)MPa
PE100 10.0
PE80 8.0

22. Fittings of MDPE
FITTINGSOF MDPE-
1. Saddle
2. Coupler
3. Elbow
4. Tee
5. End cap
6. Reducer

23. TOOLS & TACKLES-
TOOLS & TACKLES-
1- MDPE PIPE CUTTER
2- UNIVERSAL STRAP WRENCH
3- REROUNDING TOOL

24. TOOLS & TACKLES-
4- SCREAPER
5- ALIGNEMENT CLAMP.
6- MANHOLE COVER LIFT KEY
7- ELECTRO FUSION MACHINE

25. DRS/FRS
• Inlet pressure - 19-26 bar.
• Outlet pressure – Below 7 bar.
• DRS stand for high flow Capacity for a whole
district.

26. DRS/FRS Flow Chart
Below 7 ba

28. Service Regulator (SR)
• Inlet pressure – 4 bar (4000 Mbar)
• Outlet pressure – 100 Mbar
• Capacity – 100 scmh,
• 150 scmh…ets
• To connect lage no of
• customer as per sr
• Capacity.

29. Regulator
• Inlet pressure – 4 bar
• Outlet pressure – 21 mbar
• Flow capacity – 6.5 scmh
• Only connect 10 – 12
• Customer.

30. Meter Regulator
• Inlet pressure – 100 mbar
• Outlet pressure – 21 mbar
• Flow capacity – 2.5 scmh

31. Meter
• Inlet pressure – 21 mbar
• Outlet pressure – 21 mbar
• P max – 0.5 bar
• Rating – G 1.6
• Min flow- 0.016 m3/h
• Max flow – 2.5 m3/h
• Type – Diaphragm.
• Flow capacity -2.5 m3/H
• Capacity in – 1.2 Liter.

32. Pressure
• Gauge Pressure.
• When pressure is measured relative to atmospheric
pressure (14.7 psi), it is called gauge pressure (psig).
The term gauge pressure is applied when the pressure
in the system is greater than the local atmospheric
pressure
• Absolute pressure
• When pressure is measured relative to a perfect
vacuum, it is called absolute pressure

33. Pressure

34. Domestic gas pressure
• Pressure in domestic gas pipeline
• 1.01325 + .21 = 1.22325 bar
• 1223 mbar

35. Type of Gas Meter
• Diaphragm.
• RPD (rotatory positive displacement) (above
0.5 bar Pressure)
• Turbine meter. ( above 20 bar Pressure)
• Orifice meter
• Ultrasonic flow meters.
• Coriolis meter

36. Meter selection
• G -1.6 (min 0.016 max 2.5) M3/h
• G-2.5 (min 0.025 max 4 ) m3h
• G- 4 (min 0.04 max 6 ) m3/h
• G-6 (min 0.06 max 10) m3/h
• G-10 (min 0.10 max 16) m3/h
• G-16(min 0.16 max 25) m3/h
• G-25 (min 0.25 max 40) m3/h

37. Meter selection
• Total Consumption – 250 scmh
• Consumption in m3/h = Consumption/
correction factor = 250/2.936
• Consumption – 85.14 m3/h
• G – 65 (min 0.65 max 100)

38. What is scm ?
• Standard Cubic Meter means the quantity of
Gas that occupies a volume of one (1) cubic
meter at a temperature of 15oC (fifteen
degrees Celsius) under an absolute pressure of
1.01325 Bar.

40. •~~~~ THANK YOU ~~~~