natural gas transmission pipeline safety related presentation.pdf

“Conference on Chemical (Industrial) Disaster Management-Bangalore” 1
Measures adopted for Monitoring
Safety of Natural Gas Pipelines
By
S. P. Garg
General Manager (HSE)
Corporate HSE Department
GAIL (India) Limited
Email: sp.garg@gail.co.in

Natural Gas
 Natural gas is a naturally occurring
hydrocarbon gas mixture consisting
primarily of methane, but commonly
includes varying amounts of other higher
hydrocarbons and a lesser percentage of
carbon dioxide, nitrogen, and hydrogen
sulphide.
 It is colourless, shapeless and odourless.
 Natural gas is an energy source often
used as a fuel for heating, cooking, and
electricity generation.
 It is also used as fuel for vehicles and as a
chemical feedstock in the manufacture
of plastics and other commercially
important organic chemicals.

Pipeline System
 The rapid growth of business all over the world requires increasing
hydrocarbon transport capacity.
 A pipeline is actually a system of equipment designed to allow material to
flow continuously or intermittently from one location to another.
 With sophisticated technologies providing increased applications, pipelines
are gaining advantage over other means of transport due to economic and
safety considerations.

Hydrocarbon Pipeline Network in the World
0
500000
1000000
1500000
2000000
World Total United State India
1942669
793285
29684
Hydrocarbon Pipeline Network (in KM)
(Year 2010)
 The United States has largest pipeline network in the world. Its natural gas
pipeline network is a highly integrated transmission and distribution grid
(548,665 km) that can transport natural gas to and from nearly any location
in the lower 48 States.

Natural Gas Pipelines (in KM) in India
10000
1400
2000
500
0 2000 4000 6000 8000 10000 12000
GAIL
RIL
GSPL
Others
 India has a country wide network of approx 14,000 kms of gas pipelines (and another
approximate) 12,000 kms of pipelines are under construction.
 By 2017 India will have a natural gas pipeline grid of approx 30,000-kms connecting
consumption centres to sources of fuel.

Natural Gas – Production, Transmission & Distribution
Source: Internet

Natural Gas Pipeline System
A Natural Gas pipeline system may contain following elements:
 Buried Pipelines
 Above Ground Pipelines
 Compressor Stations
 Isolation Valves – Manually, Remotely or Automatically activated
 Relief Valves – Pressure or Thermal
 Pipe Bridges or other Supports
 Casing Sleeves under Road/Rail Crossing
 Leak Detection System
 Pig Launchers/Receivers
 Control Systems

Natural Gas Pipeline System

Hazards associated with NG Pipelines
 Natural Gas is highly flammable substance, transported through cross
country pipelines at high pressure often close to centres of high population
or through areas of high environmental sensitivity.
 Natural Gas pipeline system pose severe hazard problems for human being
and property in the vicinity.
 Provision of protective measures are essential for safe operation of NG
Pipeline system. The requirement is based on
o Hazardous properties of Natural Gas.
o Quantity of Natural Gas, which could be released and its effect.

Properties of Natural Gas
NATURAL GAS : CHEMICAL FORMULA : CnH2n+2, n=1,2.....
PROPERTIES OTHER CHARACTERISTICS
Type of chemical
Physical form
Ignition temp. oC
Flash point
Explosive limits % Vol in air
Solubility in water
Vapor Density (Air=1)
Sp. Gravity
: Flammable gas
: Gas
: 535 oC
: Not available
: 5 to 15
: Insoluble
: 0.6
: 0.42
Colorless, odorless gas can be
compressed to liquid at very low
temperature.
HAZARDS PRECAUTIONS EXTINGUISHING AGENT
FIRE: Highly Inflammable
EXPLOSION: Gas forms an
explosive mixture with air.
No open fire, sparks, no smoking.
Use explosion-proof electrical Equipment Gas
tests with LEL Meter suitable for methane.
Shutting off supply is essential before
extinguishing fire using dry chemical
powder.
SYMPTOMS PRECAUTIONS FIRST AID
Inhalation : Dullness,
breathlessness
Ventilation, local air extraction, use of
respirator.
Remove the person to fresh air and
resort to artificial respiration if
necessary. Report for medical attention
DISPOSAL STORAGE ANTIDOTES
Intermittent cold flaring Storage in cool, well ventilated place and
isolate for oxidizing agents.
Outdoor or detached storage is preferred.
NIL
Additional information: High concentration in air cause oxygen deficiency leading to unconsciousness.

Hazards of Natural Gas
 Fire Hazard : The fire is a process of burning that produces heat, light and
often smokes and flames. The effect of fire on the people takes the form of
skin burn on exposure to thermal radiation.
Radiation Level
(kW/m2)
Observed Effect
37.5 Sufficient to cause damage to process equipment
25
Minimum energy required to ignite wood at indefinitely long exposures (non-
piloted)
12.5
Minimum energy required for piloted ignition of wood, melting of plastic
tubing
9.5 Pain threshold reached after 8s; second degree burns after 20s
4
Sufficient to cause pain to personnel if unable to reach cover within 20s;
however blistering of the skin (second degree burns) is likely; 0: lethality
1.6 Will cause no discomfort for long exposure

Flash Fire: A flash fire occurs when a
cloud of flammable gas and air is ignited.
Jet Fire: A jet fire occurs when a flammable
liquid or gas is ignited after its release from
a pressurized, punctured vessel or pipe.
(8kg/s – 35 m)

 Explosion (Unconfined Vapour Cloud Explosion):
 An accidental escape of flammable material to form a cloud and obtained
delayed ignition.

Fire erupted in one of the Natural Gas Pipeline
Minneapolis — A natural gas-fueled fire erupted in south
Minneapolis on Thursday morning, March 17, 2011. The
fire forced Interstate 35W to close in both directions,
though it reopened late in the morning. There were no
reported injuries and the fire was extinguished.
Rupture of Transcanda Natural Gas Pipeline
ST. PIERRE-JOLYS, Manitoba, Canada, January 27, 2014 (ENS) – A
TransCanada natural gas pipeline ruptured and exploded early
Saturday morning in an isolated area near the town of Otterburne,
25 kilometers (15 miles) south of Winnipeg. The pre-dawn pipeline
break and resulting explosion sent a massive fireball into the night
sky.
(1994)[Explosion] a 36-inch TETCO natural gas transmission pipeline explodes in Edison,NJ
At 2357 hours on March 23, 1994, a 36-inch Texas Eastern Transmission Corporation
(TETCO) natural gas transmission pipeline, operating at 975 psi, catastrophically ruptured
in Edison Township, New Jersey, initiating a fire event of enormous magnitude, the largest
fire incident ever to occur in Middlesex County. The 80-foot-long rupture in the pipe
occurred on property occupied by the Quality Materials, Inc. asphalt plant and ripped a
crater approximately 100 feet long, 50 feet wide, and 40 feet deep.

Natural Gas Transmission – Failure Categorization
Characteristics of the Pipeline Failure:
 Pinhole/Crack: the diameter of the hole is smaller that or equal to 2 cm.
 Hole: the diameter of the hole is larger than 2 cm and smaller than or equal to the
diameter of the pipe.
 Rupture: the diameter of the hole is larger than the pipeline diameter.
The Initial Causes of Incident:
 External Interference
 Corrosion
 Construction Defect/Material Failure
 Hot Tap made by Error
 Ground Movement
 Other and unknown
Source: EGIG Report

Natural Gas Transmission – Primary Failure Reason
Source: EGIG Report
External
Interference
Digging, Piling,
ground works etc.
Achor, bulldozwer,
excavator etc.
Casing, sleeves
etc.
Corrosion
External
Internal
Others
Construction
Defect
Construction or
material
Welding defects
etc.
Failure of
component
Ground
Movement
Dike Break,
erosion, flood
Landslide
Mining & others
Other
Lightning
Maintenance etc.

Calculation of Hazard Distances & Thermal Radiation
 Example of estimated Failure Scenarios for Natural Gas Pipeline diameter 42”
at line pressure 80 Kg/cm2. (NR – Not Reached)
Location
Release of
Gas
(Kg/Sec)
Distances for different Thermal
Radiation (KW/m2) intensity and 3D
weather condition.
LFL distance (m)
for 3D weather
condition.
4.5 12.5 37.5
Case 1 – 5 mm Diameter Hole (A/G) 0.29 9 8 NR 5
Case 1 – 5 mm Diameter Hole (U/G) 9 5 NR 3
Case 2 – 20 mm Diameter Hole (A/G) 4.56 39 32 26 29
Case 4 – 20% CSA (U/G) 2519 577 390 NR 211

Calculation of Hazard Distances & Thermal Radiation
 Example of estimated Failure Scenarios for Natural Gas Pipeline diameter 42”
at line pressure 80 Kg/cm2.
Location
Release of
Gas
(Kg/Sec)
Distances for different Thermal
Radiation (KW/m2) intensity and 3D
weather condition.
LFL distance (m)
for 3D weather
condition.
4.5 12.5 37.5
Location of gas leakage and fire
26 M distance of heat radiation of 37.5 KW/m2
Radiation Level (kW/m2) Observed Effect
37.5 Sufficient to cause damage to process equipment
12.5 Minimum energy required for piloted ignition of wood, melting of plastic tubing
4
Sufficient to cause pain to personnel if unable to reach cover within 20s; however blistering of the skin (second
degree burns) is likely; 0: lethality

Statistics of Gas Transmission Pipeline Incident - EGIG
 In 1982 six European gas transmission system operators took the initiative to
gather the data on the unintentional release of gas in their transmission
pipeline system known as EGIG (European Gas Pipeline Incident Data Group) .
 EGIG has maintained the European Gas Pipeline Incident Database of fifteen
European Countries on more than 135000 KM of pipelines every year.
 The statistics of incidents collected in the database give reliable failure
frequencies. The overall incident frequency is equal to 0.35 incidents per year
per 1000 Km over the period 1970 to 2010.

Source: EGIG Report
Statistics of Gas Transmission Pipeline Incident - EGIG
0.17
0.057 0.059
0.017 0.026
0.057
0.04 0.031
0.011 0.015
0
0.02
0.04
0.06
0.08
0.1
0.12
0.14
0.16
0.18
Primary Failure Frequency (1970-2011) per 1000 KM/Yr.
Primary Failure Frequency of 5 Year Moving Average per 1000 KM/Yr.
48.4
16.1
16.7
4.8
7.4
6.6
0 20 40 60
External Interference
Corrosion
Construction…
Hap tap made by error
Ground Movement
Other and Unknown
Primary Failure Cause Disribution (%)
External Interference
Corrosion
Construction
Defect/Material Failure
Hap tap made by error
Ground Movement
83%
13%
4%
Corrosion Distribution (%)
External
Internal
Unknown
41.3
16.5
15.6
7.5
1.6
17.5
Incident Distribution on Detection
Public/Land Owner
Patrol
Contractor
Company Staff
Online Inspection
Others

Statistics of Cross Country Pipeline Incidents - OISD
0
2
4
6
8
10
12
04-05 05-06 06-07 07-08 08-09
3
5
11
4
8
2
4
3
1
3
Nos. of Incident (including Fire Incident)
Nos. of Fire Incident
10%
3%
13%
10%
10%
19%
35%
Probable Causes
Pipeline Rupture
Fall from Height
Electrical related
Pipeline Maint./Repair
Corrosion
Construction
3rd Party Damage
Source: Analysis of Major Incidents in Oil & Gas
Industry 2004-2009 by OISD

Framework – Safety in Natural Gas Pipeline in India
Construction, Operation & Maintenance of Natural Gas
Pipeline System
PNGRB
(Technical & Safety
Standard of Natural Gas
Pipelines)
OISD
(Standard 226 – Natural
Gas Transmission Pipeline
and City Gas Distribution
Network)
ASME 31.8
(Gas Transmission and
Distribution Piping
Systems)

Applicable Statutory Compliances
 Petroleum and Natural Gas Regulatory Board (PNGRB) Act’2006.
 Guidelines for Environmental clearance of new projects – 1981
 The Environment (Protection ) Act -1986
 Water ( Prevention & Control of Pollution) Act 1974
 Air ( Prevention & Control of Pollution) Act 1981
 The Petroleum and Mineral Pipelines (Acquisition of Right of Users in Land)
Act, 1962.
 Manufacture, Storage & Import of Hazardous chemical Rules-1989
 National Highway Act, 1956
 Railways Act , 1989

Safety Aspects of NG Pipelines - Construction
 National & International Standards like OISD, PNGRB, IS, ASME 31.8B, API
etc. are being followed during design, construction, operation &
maintenance.
 Proper layout & inter distance of facilities are maintained as per OISD Std.
226 & PNGRB Regulations.
 Sizing of pipeline wall thickness according to the population density of the
area, design pressure, specified minimum yield strength, diameter of the pipe
longitudinal joint factor and temperature de-rating factor as per ANSI/ASME
B 31.8.
 Additional corrosion allowance of minimum 2 mm of design wall thickness
considering 30 years pipeline design life and moderate corrosion rate.

SN Locations Minimum Cover
(In Mtr)
i) Area of agricultural, horticultural activity,
limited or no human activity, industrial
commercial and residential area
1.0
ii) Rocky terrain 1.0
iii) Drainage, ditches at roads/railway crossing 1.0
iv) Minor river crossings/canal/drain/nala/ditches 1.5
v) Major river crossing (below scour level) 2.5
vi) River with rocky bed (below scour level) 1.5
vii) Area under influence of tides 1.5
viii) Cased/Uncased road crossing 1.2
ix) Cased railway crossing 1.7
 Pipeline Cover:

A zone, 400 m wide, shall be considered along the pipeline route with the pipeline in the centre-line
of this zone. Then the entire route of the pipeline shall be divided into random lengths of 1600 m
such that the individual lengths will include the maximum number of buildings intended for human
occupancy. The number of such dwellings which are intended of human occupancy within each 1600
m zone shall be counted.
Location Class 1 – A Location Class 1 is any 1600 m section that has 10 or fewer dwellings intended for human
occupancy. This Location Class is intended to reflect areas such as wastelands, deserts, mountains, grazing lands,
farm lands and other sparsely populated areas.
Location Class 2 – A Location Class 2 is any 1600 m section that has more than 10 but less than 46 dwellings
intended for human occupancy. Location Clas 2 is intended to reflect areas where degree of population is between
location Class 1 and Location Class 3 such as fringe areas around cities and towns, industrial areas, ranch or country
estates, etc.
Location Class 3 – A Location Class 3 is any 1600 m section that has 46 or more dwellings intended for human
occupancy except when a Class 4 Location prevails and is intended to reflect areas such as suburban housing
developments, shopping centers, residential areas, industrial areas, and other populated areas not meeting
Location Class 4 requirements.
Location Class 4 – A Location Class 4 include areas where multi-storey buildings are prevalent, and where traffic is
heavy or dense and where there may be numerous other utilities underground. Multi-storey means four or more
floors above ground, including the ground floor and irrespective of depth of basement or number of floors of
basement.
 Location Class:

 Pipeline having 3 layer polyethylene external coating.
 Installation of remotely operated sectionalizing valves at regular intervals of
approximate 8-32 KM based on Location Class.
 Provision of Intermediate pigging stations at the distance of approximate 90
KM along with the pipeline route to meet the pigging requirement of
pipelines.
 Provision of slug catcher made at Compressor Station to collect the
impurities, if any.
 Pressure safety valves at the Intermediate Pigging Stations provided to take
care of excess pressure.

 Installation of casing pipes at all railway crossing and highway crossing as
per International Standards.
 Pipeline markers like warning boards, kilo meter/aerial markers or boundary
pillars along the pipeline route.
 Open Path Gas Detection System at Pipeline Installations area.
 Automatic fire detection and suitable fire extinguishing system is installed at
all Installations.
 Cathodic Protection System provided for pipeline against corrosion.
 Corrosion sensing probes for monitoring external corrosion rate.

 Provision of SCADA to ensure effective and reliable control, management and
supervision of the pipeline.
 Provision of Electrical Equipment based on Area Classification.
 Environmental consideration based on Environmental Impact Assessment
(EIA) & and Risk Analysis (RA) study for the pipeline and stations before
construction of pipeline.

Safety Aspects of NG Pipelines – Operation & Maintenance
 Health, Safety and Environment Management System
• HSE Policy Statement & objectives to ensure implementation of the policy
• Set of detailed processes supporting each activity of the HSE management system.
• Development of Operation and Maintenance Procedures
• Implementation of control and monitoring activities
• Periodic, monitoring, review and reporting of performance
• Compliance Audit - External and Internal Safety Audit
• Accident Reporting system
• Emergency Management System to safely handle emergencies with minimal risk (ERDMP).
• Hazard Identification Processes such as HAZOP
• Risk Analysis and Risk Assessment Process such as QRA
• Work Permit System to ensure work is carried out in safe manner.
• Structured Training System for O&M employees including contract workers, security etc.
• Development of Management of Change procedures to identify and consider the impact of
changes to pipeline systems and their integrity.

 Deployment of comprehensive Operation and Maintenance Procedures for
Control System and Safety Interlocks.
 Operating Procedures mainly includes:
• System Description
• Operation set points
• Initial start up
• Normal operations
• Normal shut down procedure
• Temporary operations
• Execution of emergency shut down in a safe & timely manner
• Emergency shut down
• Conditions under which emergency shutdown is required
• Emergency operations
 Development of detailed maintenance procedure for entire pipeline system
considering the manufacturer’s recommendations and stipulated Standards
OISD/PNGRB.

 Establishment of National and Regional Gas Management Centres as part of
holistic monitoring and control of pipeline system. It consists of
• Monitoring of overall pipelines and installations
• Maintaining Pipeline Hydraulics to meet customer requirement
• Control on Remote Operated Valves of Pipeline Installations
• Management of parameter deviation or alarm, if any
• Healthiness of Fire Protection System of Installations
 Formation of integrity management program framework to ensure continual
/ periodic assessment. An evaluation process to measure effectiveness of the
current health of the pipeline and to prevent any failures in future.

Gas Management Centres - GAIL
NGMC
RGMC
AGRA-F’BAD
RGMC
NCR
RGMC
GUJ.
RGMC
AP
RGMC
TN
RGMC
TRIPURA
RGMC
MAH
Real time data of all Pipeline
Parameters, Supply and Delivery
Conditions at all Sources and Major
Customer terminals through SCADA
Instant leak detection
with the help of Remote
Terminal Units (RTUs)

 Right of Way for Inspection and Maintenance:
• Road and Highway Crossing – Once in a 3 months.
• River Crossing – Twice in a year (Before and after Monsoon)

 Pipeline Patrolling:
• Ground Patrolling – Once in a month
• Foot Patrolling – Line walk by Company Official twice in year (Before and after
Monsoon)
View of Arial Patrolling of Pipelines

 Pipeline Pigging:
• Pigging Activities for Wet Gas – Once in a year
• Pigging Activities for Dry Gas – Once in a 3 years
 Intelligent Pipeline Pigging to be carried out once in a 10 years and data
must be compared with data obtained during Geometric Pigging before
commissioning to ensure health of pipelines.
Intelligent Pigging of Pipelines

 Inspection of Cathodic Protection System:
• PSP (Pipe to Soil Potential) at feeding point – Once in a fortnight
• PSP Reading at Test Lead Point all along the Pipeline – Once in a 3 months
• Cathodic Protection Rectifier – Once in a 2 months
 Coating Survey:
• Pearson Survey / Direct Current Voltage gradient (DCVG) / Continuous Potential
Logging (CPL) survey / Current Attenuation Test (CAT) once in 5 years to ensure
the healthiness of pipeline coating.

 Awareness:
• Display of Do’s & Don’ts
• Conducting a comprehensive public awareness program for consumers and general
public. The educational material to be prepared in local Hindi and English language.
Local audio visual media available should be used for such educational programs.

 Fire Protection System:
• Installation of gas detection system equipped with audio and visual alarm.
• Provision of IR / Smoke detectors in control room, MCC, utility room and
compressor enclosure with provision of indication, alarm and annunciation.
• Installation of Electric operated fire sirens with audible range of 1 km and/or
hooters of F&G system audible within the compressor station premises.
• Installation of manual call points at strategic locations.
• Manual operated fire siren shall also be provided at strategic locations.
• Provision of Fire Fighting Equipment at Compressor Stations, Intermediate
Pigging Station, Sectional Valve Stations, Gas Entry / Exit terminals and
Metering Stations.
• Provision of Windsock on an appropriately elevated structure like the control
room / fire-water pump house in such a manner so as to avoid blind areas.

 Fire Protection System:
• Adequate communicate system at all intermediate stations including IP
stations / Repeater station.
• The Fire water system shall be provided at compressor stations consisting of:
a. Fire water storage
b. Fire water Pumps (Main and Jockey)
c. Fire water distribution piping network
d. Fire hydrant / Monitors
e. Water sprinkler / deluge system.
• Fire water system should be designed to fight two major fires simultaneously
anywhere in the installation and designed on the basis that the city fire water
supply is not available close to the installation.
• Water requirement for fire fighting to be met through water storage tanks. The
effective capacity of the tanks above the level of suction point should be
minimum 4 hours aggregate capacity of the pumps.

The integrity of Natural Gas Pipeline System is achieved through
continuous efforts at all stages to ensure that pipeline is
designed, commissioned, operated and maintained as per
stipulated codes, standards and guidelines.
Continual technological up-gradation in operation, inspection and
maintenance enhances the safety of pipeline system and
increases overall safety to great extent.

natural gas transmission pipeline safety related presentation.pdf

Recommended

Recommended

More Related Content

Similar to natural gas transmission pipeline safety related presentation.pdf

Similar to natural gas transmission pipeline safety related presentation.pdf (20)

Recently uploaded

Recently uploaded (20)

natural gas transmission pipeline safety related presentation.pdf