lpg pipeline

8/10/2019 LPG Pipeline

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UNIVERSITY OF

PETROLEUM & HINDUSTAN

ENERGY STUDIES PETROLEUM

CORPORATION

LIMITED

MANGALUR–HASSAN-

BANGALORE/MYSORE LPG PIPELINE

Summer Internship Report

Mahesh .V

SAP ID 500026333

ROLL NO : 18

MTECH Pipe Line

UPES

Dehradun



1

Contents1.0 Introduction: ........................................................................................................................................... 3

2.0 PIPELINE DESIGNING ............................................................................................................................... 4

2.1 Key parameters ....................................................................................................................................... 4

2.1.1 Main pipeline ....................................................................................................................................... 4

2.1.2 Spur Pipe Line .................................................................................................................................. 5

2.2 CODES AND STANDERDS ......................................................................................................................... 5

2.2.1ASME Standards .................................................................................................................................... 5

2.2.2ASTM Standards .................................................................................................................................... 6

2.2.3API Standards ........................................................................................................................................ 6

2.2.4 MSS Standards ..................................................................................................................................... 7

2.2.5 DIN/EN Standards ................................................................................................................................ 7

2.2.6 ISO Standards ....................................................................................................................................... 7

2.2.7 NACE Standards ................................................................................................................................... 8

2.2.8 Oil Industry Safety Directorate (OISD Standards) ................................................................................ 8

2.3 Pipeline and Associated Facilities Design................................................................................................ 9

2.3.1 Pipeline................................................................................................................................................. 9

2.3.2 Materials .............................................................................................................................................. 9

2.3.3 External Corrosion Coating .................................................................................................................. 9

2.3.4 Internal Corrosion Monitoring ........................................................................................................... 10

2.3.5 Insulating Joints ................................................................................................................................. 10

2.3.6 Pipe Wall Thickness ............................................................................................................................ 10

2.3.7 Sizing of Pipeline ................................................................................................................................ 11

2.3.8 Welding .............................................................................................................................................. 11

2.4 Basic Design Formulas ........................................................................................................................... 12

2.4.1General Flow Equation ........................................................................................................................ 12

2.4.1.1Effect of pipe elevation: ................................................................................................................... 12

2.4.2 Velocity of Gas in a Pipeline ............................................................................................................... 13

2.4.3 Reynolds No. ...................................................................................................................................... 14

2.4.4 Friction Factor .................................................................................................................................... 14



2

2.4.5 Compressibility Factor ....................................................................................................................... 15

2.4.6 Design Pressure .................................................................................................................................. 15

2.4.7 Pipe Weight ........................................................................................................................................ 16

2.4.8 Line Pipe Thickness ............................................................................................................................ 17

3.0 PIPELINE CONSTRUCTION PROCEDURE ................................................................................................ 19

3.1 Statuary Permission .............................................................................................................................. 19

3.2 Pipe Laying Activities: ............................................................................................................................ 20

3.2.1 Movement and Staging of Pipeline Components and Construction Equipment: .............................. 20

3.2.2 Clearing and Grading .......................................................................................................................... 20

3.2.3Stringing .............................................................................................................................................. 21

3.2.4 Trench Excavation .............................................................................................................................. 21

3.2.5Cold Field Bending .............................................................................................................................. 22

3.2.6 Welding procedure ............................................................................................................................ 22

3.2.7 Weld Joint Numbering ....................................................................................................................... 23

3.2.8 Cleaning of Edges and Bevel Inspection ............................................................................................ 24

3.2.9 Lowering and Backfilling of Pipe Section ........................................................................................... 24

3.2.10 Hydro Testing ................................................................................................................................... 25

3.2.11 Final Grading and Reclamation ........................................................................................................ 26

4.0 PRECOMMISSIONING ............................................................................................................................ 27

4.1Precommissioning activities................................................................................................................... 27

4.1.1 System Check ..................................................................................................................................... 27

4.1.2 Checking of Field Instruments ........................................................................................................... 27

4.1.3 Survey of the Pipeline ........................................................................................................................ 28

4.1.4 Checking of Communication System ................................................................................................. 28

4.1.5 Checking of Electrical Distribution System ........................................................................................ 28

4.1.6 Checking of Instruments, Control & Interlock ................................................................................... 28

4.1.7 Checking of Utilities ........................................................................................................................... 28

4.2 Dewatering ............................................................................................................................................ 29

4.3 Swabbing ............................................................................................................................................... 29



3

1.0 Introduction:

HPCL intend to build a LPG Pipeline from its LPG import facilities at Mangalore to receiptat Bangalore via Hassan and subsequently provided a spur to mysore via Kalibadi. The pipeline

is proposed through the existing Mangalore-Bangalore pipeline corridor

The proposed HPCL LPG pipeline will starts from HPCL Mangalore LPG import facilities

(MLIF) to receipt terminal at Devangudi , Bangalore via Hassan. The proposed LPG pipeline has

a mainline length of 362km from Mangalore to Bangalore .The pipeline has tap-off for Hassan at

chainage 164 km and is further extended to Mysore Terminal (106 km via Hassan).The proposed

pipeline has 8.4 km length spurline to Yediyuru at chainage 294.45 km on mainline and 3.2 kmlength spurline to Solur at chainage 287.79 km on mainline .The pipeline has a further tap-off

provision at Handanhalli village for extending the pipeline to Coimbatore.

The estimated Flow Rate of the proposed pipeline is 1.12MMTA (330.66 cum/h) & The

operation hours of 16 hr. per day to be considered



4

2.0 PIPELINE DESIGNING

2.1 Key parameters

Pipeline Operating Life : 35 years

Operating hours : 16 hours per day (365 days/year)

Pigging Facilities : Permanent pigging facilities suitable for

. Intelligent pigging” to all mainline and spur line

Subsoil Temperature : 200C through the entire length of the pipeline

(1.2 m below ground)

Pipeline Laying : Buried Station Premises SV: Under Ground Dispatch/Receiving Station/IP/Pump station Above ground

Sectionalizing Valve : Sectionalizing valves have been proposed at

maximum distance of 12km as per ASME

B31.4 &OISD-24 and as per evaluation profile

requirement

Pressure Control Valves : 1 PCV at each pump and receiving station

Remote Operated Valves : 1 ROV at each receiving station

Pipeline Corrosion Protection : External coating and impressed current

Cathodic protection

2.1.1 Main pipeline

Main Pipeline Diameter : 16”, 14”,10” &8” for Mangalore to Bangalore

Main Pipeline Length : 362.3kms

Material of construction : Carbon Steel

Material Grade of Line pipe : API5L Gr.X60 PSL 2

Pipeline Corrosion Allowance : 0.5 mm per cl.402.4 of ASME B 31.4

Design Pressure : 99.9 kg/cm2

Design Temperature : -20 to 650C

Thickness : 7.9mm, 6.4mm (variance with dia.)

Pipeline Roughness : 45 microns



5

2.1.2 Spur Pipe Line

Spur Line Length : 1) Hassan to Mysore (106km) 2) Intermediate dispatch station for Banglore

to receiving Station Yadiyuru (8.40kms)

3) Tap-off Solour to receiving station solor(3.20)

Spur pipeline Diameter : 10” (106kms) ,8”(8.40kms), 6”(3.20kms)

Material of Construction : Carbon steel

Material Grade of Line pipe : API 5L Gr.X60 PSL2

Pipeline Corrosion Allowance : 0.5 mm per cl,402.4 of ASME B 31.4

Design Pressure : 99.9kg/cm2

Design Temperature : -20 to 65

0

C Thickness : 6.4 mm of 10 inch ,8 inch & inch

Pipeline Roughness : 45 microns

2.2 CODES AND STANDERDS

The following codes and standards are used for the design of pipeline

2.2.1ASME Standards

ASME B31.4 Pipeline transportation systems for liquid hydrocarbon &

other fluids

ASME B16.47 Large diameter steel flanges (NPS 26 through NPS 60)

ASME B16.48 Steel line blanks

ASME B16.34 Valves- flanged, threaded and butt welding end

ASME B16.25 Butt welding ends

ASME B16.5 Pipe flanges and flanged fittings



6

ASME SEC VIII, DIV-1 Boiler and Pressure Vessel code

ASME SEC IX Qualification slandered for welding and brazing

ASME B16.9 Factory-made wrought steel butt welding fittings

ASME B16.10 Face to face and end to end dimension of valves

ASME B16.20 Metallic Gaskets for pipe Flanges-Ring-Joint

ASME B31.3 Process Pipeline

ASME B36.10 Welded and seamless wrought steel pipe

2.2.2ASTM Standards

ASTM A 53 Pipe, Steel, black and hot-dipped zinc coated welded and seamless

ASTM A 105/A 105 M Carbon steel Forgings for pipe components

ASTM A 106 Seamless carbon steel pipe for high temperature service

ASTM A 320/A 194 M Carbon and alloy steel nuts for bolts for high temperature service

ASTM A 320/A 320 M Alloy steel bolting materials for low temperature service

ASTM A 330/A 333 M Seamless and welded steel pipe for low temperature service

ASTM A 370 Mechanical testing of steel products

ASTM A 381 Metal-arc-welded steel pipe for use with high-pressure transmission

System

ASTM E 112 Standard methods for determining the average grain size

2.2.3API Standards

API 5L Specification for line pipe

API 520 Sizing selection and installation of pressure relieving devices

in refinery



7

API 540 Electrical installation of petroleum processing units

API 1104 Welding of pipeline and relative facilities

API 6D Pipeline valves

API RP 1102 Steel pipeline crossing Railroad & highways

API 6 FA Specification for fire test for valves

API 607 Fire test for soft-seated quarter turn valve

API 610 Centrifugal Pump for general refinery service

2.2.4 MSS Standards

MSS SP 25 Standards marking system for valves, fittings, flanges and union

MMS SP 44 Steel pipeline flanges

MSS SP 75 Specification for high test wrought butt welding fittings

2.2.5 DIN/EN Standards

EN 10204 Metallic products: types of inspection documents

EN 10045/1 Metallic products: Charpoy impact test-test methods(V &U notches)

DIN 30670 Polyethylene coatings for steel pipe and fittings

2.2.6 ISO Standards

ISO 148 Determine the impact strength of steel and energy absorbed by charpy

V-notch

ISO 15590- 1 Induction bends, fittings and flanges for pipeline transportation



8

ISO 9001 Quality Management Standards

2.2.7 NACE Standards

MR0175 Sulphide Stress Cracking Resistant Metallic Material for Oilfield

Equipment

2.2.8 Oil Industry Safety Directorate (OISD Standards)

OSID – Stanadard-214 Cross country LPG pipeline

OSID – Standard-114 Hazardous chemical and their handling

OSID-Standard-113 Classification of areas for electrical installation

OSID-Standard-118 Layout for Oil and Gas Installation

OSID-Standard-119 Inspection of Pumps

OSID-Standard-141 Design and Construction requirement for Cross Country

Hydrocarbon Pipelines

OSID-Standard-138 Inspection of Cross Country Pipeline Onshore

OSID-Standard-114 Liquid Petroleum Gas (LPG) installation

OSID-Standard-150 Design and safety requirement for LPG mounted Storage

facility

OSID-Standard-163 Process Control Room Safety



9

2.3 Pipeline and Associated Facilities Design

Pipeline and pipeline stations to be installed as a part of this project shall be designed and

engineered in accordance with the standards/codes.

2.3.1 Pipeline

Pipeline shall be designed in accordance with requirements of ASME B31.4 & OISD 214. The

pipeline thickness shall be calculated using a design factor of 0.72. Higher wall thickness shall

be used at river crossings, NH, SH, Railways, MDR & between NERIYA & SV06. For all other

locations a design factor of 0.72 will be considered. At cased crossings higher wall thickness

pipes may be used based on the requirements of concerned authorities. Pipeline shall withstand

all installation, testing and operating conditions/loads. All necessary calculations should becarried out to verify structural integrity and stability of the pipeline for the combined effect of

pressure, temperature, bending, soil/pipe interaction, external loads and other environmental

parameters as applicable during all phases of work from installation to operation.

2.3.2 Materials

Line pipe shall conform to latest edition of API 5L. Additional dimensional, NDT and other

requirements over and above API 5L, shall be identified taking into account the construction,

quality control and other aspects. Type of line pipe to be used shall be Seamless / LSAW /

HSAW / ERW. Line pipe material grade shall be X65 for 406.4 mm (16”) OD & 355.6 mm

(14”) OD and X52 for 273.05 mm (10”) OD & 219.85 mm (8”) OD pipelines.

2.3.3 External Corrosion Coating

Pipeline to be installed below ground shall be protected against external corrosion by acombination of high integrity externally applied coatings and permanent impressed cathodic

protection system.

The selected corrosion protection coating will be suitable for the temperature range of + 70°C, In

addition to the following properties: High integrity, Resistant to ageing and degradation ,

Resistant to attack by micro-organisms, Resistant to soil stresses , Ease of application, Resistant



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2.3.7 Sizing of Pipeline

Description Size (inch) Length Flow rate

(MMTPA)

Mainlines

Mangalore IP Station

Neriya

14 78.5 1.78

IP Station to IP Hassan 16 86.5 1.78

IP Hassan to IntermediateDispatch station for

Bangalore

10 84.5 0.803

Intermediate Despatch

station for Bangalore toSolur TOP

8 38.34 0.966

Solur TOP to Devangudi

Bangalore

8 74.51 0.6179

Spur lines

IP Hassan to Mysore 10 106.01 0.335

Solur TOP to Solur 6 3.20 0.282

IntermediateDispatch for

Bangalore to Yediyuru

8 8.40 0.348

2.3.8 Welding

Welding of pipeline section shall be carried out in accordance with API 1104 and OISD 214,

specification for welding and welding charts. Butt welds shall be 100 % radio graphed for all

pipelines. Welding and jointing qualifications shall be carried out in accordance with

ASMEB31.4 and API 1104. In Plant Piping for tie-ins, hook-up of the pipeline launcher/receiver

and other process facilities should be in accordance with P&ID’s.

The electrode used in the welding is E7010 and E6010 having 3.2mm and 4mm respectively.

The flux coated E6010 electrode is used for root pass and other is used for the further process.

80-110 A, 30-40 V direct current is used for this process.



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2.4 Basic Design Formulas

2.4.1General Flow Equation

( )

Q = gas flow rate measured at slandered condition ft3/day (SCFD)

f = frictional factor ,dimensionless

P b = base pressure ,psia

T b = base tempaeture ,0R(460+F)

P1 =upstream pressure , psia

P2 = downstream pressure, psia

G = gas gravity (air =1)

Tf = average gas flowing tempreture ,0R (460+

0F)

L = pipe segment length, mi

Z = gas compressibility factor at the flowing tempareture, dimensionless

D = pipe inside diameter ,in

2.4.1.1Effect of pipe elevation:

Case 1 (Single slope)

()



13

Where:

( )

s = elevation adjustment parameter, dimensionless

H1 = upstream elevation ,ft

H2 = downstream elevation , ft

e = base of natural logarithms (e = 2.718…..)

Case 2: Multiple slopes

2.4.2 Velocity of Gas in a Pipeline

() () ( )

u1 = upstream gas velocity, ft/s

Q = gas flow rate measured at slandered condition ft3/day (SCFD

Pb = base pressure ,psia

Tb = base temperature ,0R(460+F)

Z = gas compressibility factor at the flowing temperature, dimensionless




14

2.4.3 Reynolds No.

P b = base pressure, psia

T b = base temperature ,0R

G = specific gravity of air (1.00)

Q = gas flow rate, standard ft3/day

D = pipe inside diameter , in

µ = viscocity of gas , lb/ft-s

2.4.4 Friction Factor

i, Laminar Flow:

ii, Transition Flow:

√ ( √ ) R e > 4000



15

Where

f = friction factor, dimensionless


e = absolute pipe roughness, in

R e = Reynolds number of flow, dimensionless

2.4.5 Compressibility Factor

Pavg = Average pressure ,psig

Tf = Average temperature

Z = compressibility factor

2.4.6 Design Pressure



16

Where:

P = internal pipe design pressure

D =pipe outside diameter, in

t = pipe wall thickness, in

S = specified minimum yield strength (SYMS) of pipe material

E = seam joint factor,1.0 for seamless & submerged arc welded pipes

F = design factor

Usually 0.72 for cross country gas pipelines, but can be also low

as 0.4 depending on class location and type of construction

T = temperature deration factor=1.00 for temperature below 2500F

2.4.7 Pipe Weight

Where:

w =pipe weight

D = pipe outside diameter, in

t = pipe wall thickness, in

t = (Pi D)/2s

Pi : internal design pressure, psi(bar)

D : outside diameter of the pipe in (mm)

S : minimum yield strength of pipe,psi (MPa)



17

2.4.8 Line Pipe Thickness

The standard wall thickness is calculated in accordance with ASME B31.4,404.1.1;

tn = t+ A

where

tn : nominal wall thickness (mm)

t : pressure design wall thickness as calculated in accordance with ASMEB 31.4 for internal

pressure

A : sum of allowance, in (mm)

t

Pi : internal design pressure, psi(bar)

D : outside diameter of the pipe in (mm)

S : minimum yield strength of pipe,psi (MPa)

E : weld joint factor

0.72 : design factor of nominal wall thickness

S = 0.72 * E* specified allowable stress value

For API 5L grade X60 pipe

SMYS : 60,000 psi

E : 1.00



18

The calculated wall thickness ( tn) and slandered wall thickness (t selected) for the different

Outer Diameter of pipes are as follows

S.No. OD(inches) t(mm) A(mm) tm(mm) t selected(mm)

1 18 7.52 0.5 8.02 8.7

2 16 6.68 0.5 7.9 7.9

3 14 5.84 0.5 6.34 6.4

4 12.75 5.53 0.5 5.83 6.4

5 10.75 4.49 0.5 4.99 6.4

6 8.625 3.60 0.5 4.10 6.4

7 6.625 2.77 0.5 3.27 6.4



19

3.0 PIPELINE CONSTRUCTION PROCEDURE

3.1 Statuary Permission

The Company shall obtain a general permission from the various authorities having jurisdiction

over the area as necessary for construction of the pipeline. The responsibility of the Company

ends with providing in principle approvals. Contractor shall obtain the necessary permits like

work permit/ excavation permit/ trench opening permit etc. for all works from the authorities

having jurisdiction before the actual execution of various phases of the works and all

stipulations/ conditions/ recommendations of the said authorities shall be strictly complied withno extra cost to Company. Contractor shall also obtain all necessary permissions from the

concerned authorities for installation of pipeline at railways, roads, water crossings and local

authorities including places where blasting is required. Company may, however, assist

Contractor in obtaining such permissions, wherever required, by issuing recommendation letters

etc. In case of damage to other utilities/infrastructure, Contractor shall be responsible and the

required compensation as per the directions of concerned authorities/ Company shall be paid by

the Contractor. After completion of work, Contractor shall obtain a certificate from the

concerned authorities that the job has been completed as per their requirement and the area/land

has been restored to their satisfaction. Liasioning with the Mining authorities, if required, prior to

laying of pipeline in the mining area to be undertaken by the Contractor and also the completion

certification in respect to their satisfaction to be obtained.

The conditions mentioned in the in principle approvals from statutory Authorities already

obtained by the Company are enclosed with bid. All such requirements shall be shall be binding

on the contractor.



20

3.2 Pipe Laying Activities:

3.2.1 Movement and Staging of Pipeline Components and Construction

Equipment:

Pipe segments are normally delivered from their point of manufacture by rail to a rail off-

loading yard conveniently located to the construction ROW. From there, pipe segments are

loaded onto flatbed trucks and taken to a material laydown yard that is temporarily maintained in

an area close to the construction site. Numerous laydown yards may be constructed to support

individual pipe construction spreads. A truck typically carries a maximum of 20 pipe segments at

a time; however, this varies by pipeline diameter, wall thickness, weight, and pipe stackingmethod. Trucks will make round-trips all day between rail off-loading areas and material

laydown areas until all of the materials assigned to the laydown areas have been delivered. The

primary purpose is temporary storage of pipeline materials, laydown yards are also sometimes

used for “double joining” two pipe segments before their delivery to the ROW. Laydown and

staging areas could be in use from 3 to 12 weeks.

3.2.2 Clearing and Grading

The survey crew will carefully survey and stake the construction ROW to ensure that

only the preapproved construction workspace is cleared. The clearing and grading crew leads the

construction spread. This crew is responsible for removing trees, boulders, and debris from the

construction ROW and preparing a level working surface for the heavy construction equipment

that follows. Depending on existing soil conditions, this may require bringing in additional

materials such as stone and sand to create a temporary work road adjacent to the pipeline.

The clearing and grading crew is also responsible for installation of silt fences along the

edges of streams and wetlands as necessary to prevent erosion of disturbed soil. Trees inside the

ROW are cut down, roots are excavated; and timber is stacked along the side of the ROW for

later removal.

In virtually all circumstances, topsoils and subsoils are separately stockpiled adjacent to

the trench. The subsoil can be used to backfill the trench once appropriate bedding materials

have been placed at the bottom of the trench and the pipe has been installed



21

3.2.3Stringing

Pipes shall be unloaded from the trailers and lowered on to the ground by means of crane or

other suitable equipment, using suitable lifting devices viz. lifting hooks and the bevel of pipe

ends. Cranes shall be taken to avoid dragging and sliding. All stringing shall be carried out

during daytime in light. An overlap of about 25mm shall be kept between adjacent pipes. No

pipe shall be string before the trench is excavated to full depth and accepted by the client/MMPL

to meet the requirement of the specification. Pipes of different wall thickness shall be strung

separately. Pipe shall be strung with the use of two guide-ropes. Pipe shall be strung on sand

bags in such a way so as to match the grade profile and trench profile. The sand bag shall be

provided by the ACE.

3.2.4 Trench Excavation

Pipeline trench shall be dug by any method that may be necessary or director on the cleared and

graded right – of – way according to the routes as stated and approved by engineer in charge. In

cumulative land and other areas specifically designed by the COMPANY, top 300mm of the

arable soil on the pipeline trench top width shall be excavated and stored separately, to be

replaced in original position after backfilling and compacting of the trench. The trench shall bemade wide enough where slack loops are lowered into the trench so that no coating is rubbed or

abraded at the sides.

Normal cover and trench dimensions

LOCATION MINIMUM COVER (m)

a) Normal Terrain 1.2

b) Industrial, Commercial and Residential area 1.5

c) Rocky terrain 1.5

d) Minor water crossing / canal / drain 1.5

e) Drainage, ditches at roads/railway crossings 1.5f) Cased / Uncased road crossings 1.5

g) Cased Railway Crossings 1.7

h) Major River Crossings (Below scour level) 2.5

i) Major River Crossings (Below scour level)Open Cut

2.5 (Normal Soil) / 1.5 (Rocky)

j) Marshy areas/areas prone to flooding 1.5



22

3.2.5Cold Field Bending

The machineries which are used in the bending process are Hydraulic Pipe Bending Machine

with Lined Bending Die sets, Hydra Crane, Lifting/ Choker Belts, Holiday Testing Machine, D

meter. The Pads, Dies and Rolls of the bending equipment shall have relatively soft surface to

avoid damage to the pipe coating, wherever applicable, fully retaining bending shoe shall be

used. The ends of the each bend length shall be not involved anyway in the bending. The length

of the straight section shall permit easy joining .In no event shall the end of the bend be closer

than 1.5m from the end of the pipe.

For 10” OD Pipeline and smaller the radius of cold field shall not be less than 18D.Where D is

the Outer Diameter of the Pipeline. Bending will be performed with machines that ensurecontinuous bending without wrinkles or undulation in the curved / pipe section. A bending

mandrel is compulsory if D/t ≥50(outside diameter/ thickness)

A bending mandrel must be used if, during bending, wrinkles or undulations occur or if the

ovalisation tolerances cannot be respected. When the ambient temperature is less than 00C it is

forbidden to bend P.E – coated pipes. The thickness of the pipe wall on the outside of the bend

must remain within the tolerance limit given in the pipes

3.2.6 Welding procedure

Welding procedure qualification can be carried out in accordance with the relevant requirement

of API 1104 latest edition and Client’s specification .Welding shall be carried out by manual

shielded Metal Arc Welding (SMAW).The proposed Welding Procedure Specification for the

mainline welding is appended to this document for MMPL/HPCL review and approval,

subsequent to approval of which the procedure Qualification Tests shall be carried out at site.

The procedure qualification test shall be carried out by ACE under field conditions and shall be

witnessed by MMPL/HPCL. Once welded specimens are visually cleared .It shall be subjected to

Radiographic testing .Destructive testing shall be done as per API 1104 standard and MMPL

Specification.



23

Shielded Metal Arc Welding (SMAW):

The heat for this process is provided by an electric arc that melts a consumable electrode, with

some of the metal being welded. When the weld metal cools, it hardens to form the weld. It

having four process. a)Preheating b)Root pass c)Hot pass d) Filler 1 e)Filler 2 f) Tapping

A complete set of test results in the specified format shall be submitted to MMPL/HPCL for the

approval immediately after format completing the procedure qualification tests. Standard tests as

specified in the code shall be carried out in all class. In addition the change in filter metal from a

different Supplier will require new qualification of applicable WPS.

Visual inspection

Company/ Consultant shall carry out inspection of all welds as per the latest edition of API

1104.All finished welds shall be visually inspected foe parallel alignment of the work, excessive

reinforcement, concavity ,shrinkage ,cracks ,undercuts, dimensions, surface not exceed th limit

specified in the applicable cod/standards

Non Destructive Examination

The girth weld of the coupons welded for Welding Procedure Qualification shall be subjected to

100% examination by X-ray Radiographic examination and manual Ultrasonic Testing. Welds

shall meet the standards of acceptably as set forth in API 1104 latest edition as well as the

requirement in MMPL specification.

Destructive Testing

Having passed the visual and the non-destructive testing, the test weld shall be subjected to

mechanical test. Test shall be carried out at laboratory approved by HPCL/MMPL

3.2.7 Weld Joint Numbering

Each of the welded joints in the pipeline shall be assigned with a unique joint number as

described below:

Weld joint number shall be put on the adjacent factory coated portion of the pipe

The weld joint numbering shall be done in the direction of flow



24

In each kilometer joint number shall starts from 0.1(example k00 MJ 01 to 82 or etc.,

K01 MJ 01

The joint numbering shall be as indicated below

KXXX/ MYYY/W A ǀ B

Where

KXXX - Chainage in Kms

MYYY - For main pipeline joint no.

MYYYRW - Where cut outs are given, the first joint is defined by RW

MYYYA - Additional joint shall be identified by suffix a, b, c, d

3.2.8 Cleaning of Edges and Bevel Inspection

The edges to be welded shall be properly cleaned. In particular, ant oil, bitumen, grease and paintshall be removed by flame or solvent. Earth ,oxide, rust, sand and any other material, which

could be determined to the weld, shall be removed by means of grinding and/ or a wire brush.

This shall be effected inside and outside and for a minimum distance of 25mm from the edge of

the weld bevel.

The bevel shall be thoroughly inspected at the stage. Once pipe which have been cut back, a zone

extending 25mm back from the new field bevel, shall be ultrasonically tested to the requirement

of the line pipe specification to ensure freedom from laminations. The new bevel shall be

subjected to 100% visual and 100 dye penetrant/MPI tests .

3.2.9 Lowering and Backfilling of Pipe Section

Lowering Pipe in to Trench

The pipeline section shall be lowered after inspection and wrapping of the welded pipeline

section and clearance obtained for lowering from HPCL/MMPL. After satisfactory completion of

the trench, bottom level shall be checked to get the required minimum cover. The pipe shall fit in

the trench without being forced to remain in place until the backfilling operation is completed.

Any extra excavation that may be required for this purpose shall be done.

Before lowering in, a complete check by a calibrated full circle holiday detector for pipe coating

(PE Coating) and for field joint coating shall be carried out using at 25 KV with a calibrated

holiday detector. The examination shall the repaired as per the approved procedure and re-

holiday shall be done. In lowering the line vertical slack loops shall be placed at regular

intervals. Slack loops shall move horizontally from side to side of the trench after lowering. Until



25

enough lowered line is securely anchored by back fill , slack loops shall be suspended above the

trench on padded support of sufficient strength to prevent collapsing of the trench and in

sufficient number as that the pressure at the points of support will not damage the coating and

wrapping.

The bottom of the trench shall be pre-padded with a minimum of 0.15 M of loose earth/ sand in

accordance with the specification given herein for rock trenching which might damage the

protective coating and wrapping of pipe.

Backfilling and Dressing the Trench

Backfilling may in principle be started after the measurement like a) positioning of the pipe b)

covering of the pipeline c) location of the welded joints, concrete slabs, ballast, connection of the

telemetry cable, cable and connection boxes of the potential measuring points etc. d)

Determination of the angles and the position of each change direction. These measurement s

have been completed and the results communicated to the Owner and/or the Engineer.

Backfilling and bedding must be provided in a manner that will offer firm support for the

pipeline and not damage either the pipe or the pipe coating by the type of backfill material used

or subsequent surface activities. If the backfill material contains rocks or hard lumps that could

damage the coating, care must be taken to protect the pipe and pipe coating from damage by such

means as the use of mechanical shield material; backfilling procedures must not cause a

distortion of the pipe cross section that would be detrimental to the operation of the piping andthe passage of cleaning or internal inspection devices

3.2.10 Hydro Testing

The section of the pipelines shall be tested as a single string. All welded joint shall be exposed

and should be cleaned properly from rust and other foreign materials. The section of the pipeline

section for the crossings shall be tested as a single string. The minimum hydrostatic test pressure

shall be 1.4 times of the design pressure for gas pipeline. The combined equivalent stress in the

pipeline due to bending and test pressure shall not exceed 90% of the SMYS of the pipe material.

The test section shall be visually examined for leaks/ defects etc.



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After the temperature has been stabilized, the pressure shall be maintained in the pipeline for at

least 6 hours and recorded, “calibrated 6” dial pressure gauge one at pressure gauge one at

pressurization point and at other highest point shall be installed during testing. Pressure gauge

range should be 1.5 times of the test pressure. The accuracy of the pressure gauge to be used is

±0.1% of the full scale value.

Before filling water in the pipe section all NDT, pipe log book part A except joint coating shall

be completed. For testing of pipe section clean construction portable water shall be used. During

filling of the water proper venting shall be done at the highest point to remove all the entrapped

air.

Pipeline shall be gradually pressurized to the test pressure and intermediate checks shall be done

for any possible leakage.

During pressurization warning sign board shall be displayed as

“ KEEP AWAY – SYSTEM UNDER PRESSURE”

3.2.11 Final Grading and Reclamation

Once backfill has been placed and properly compacted, the original topsoil is returned to its

original location and final grading and contouring are performed. Depending on the vegetation

reclamation plan that has been approved, reclamation of the disturbed area above the pipeline

can begin at this time. Also at this time, as all construction work is completed for each spread,

construction equipment is removed and the construction ROW is reclaimed. However, depending

on access constraints, the construction road may remain in place until adjacent spreads are

completed, if it provides the only access to those spreads



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4.0 PRECOMMISSIONING

Pre-commissioning checks shall be carried out for the pipeline system to ascertain that the

pipeline system has been mechanically completed in all respect. These checks shall cover all the

facilities of the main cross-country pipeline (starting from Mangalore Dispatch Station to Soluru

Receipt Station and Spur Line from Hassan to Mysore as per the Scope of Work of individual

Section Contractor)

4.1Precommissioning activities

4.1.1 System Check

The entire facilities shall be checked against the latest P&ID’s, Engineering and Vendor

drawings/ documents and other design specifications. Any shortcomings observed shall be listed

down in the form of punch lists and these should be duly attended for liquidation and resolution.

The Pipeline contractor should check the station systems from the angle of precommissioning

and commissioning and spell out any additional requirement of vents/drains, temporary

arrangement/modification etc. that may be required during the pre-commissioning andcommissioning activities and arrange for the same in consultation with the Company

representative.

4.1.2 Checking of Field Instruments

All the field instruments/equipment like actuated valves, shutdown valves, transmitters ,solenoid

valves, shut down switches, alarms etc. shall be checked physically and also for their intendedapplication by simulating the actual conditions. It will also include checking of different meters,

gauges, action of actuated valves, control valves, shutdown valves etc.



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4.1.3 Survey of the Pipeline

This shall be performed to confirm that proper fittings/supports, Cathodic protection system

,route markers, warning signs, fencing around SV stations, etc. have been installed along the

pipeline.

4.1.4 Checking of Communication System

This is to check that there is proper communication with adequate back-up power to ensure

uninterrupted communication.

4.1.5 Checking of Electrical Distribution System

This is to ensure safety and also to ensure an uninterrupted power supply during startup and

normal pipeline operation.

4.1.6 Checking of Instruments, Control & Interlock

This is to check that instrument controls and interlocks are functional as per the normal operating

conditions.

4.1.7 Checking of Utilities

This is to check that utilities like power, UPS system, CCTV/LPG/Diesel generator instrument

air etc. are available prior to start-up.



4.2 Dewatering

Dewatering of a pipeline section shall be done subsequent to the hydro-test. During the

dewatering operation, the major quantity of hydro-test water shall be removed from the main

pipeline. It is the responsibility of the contractor to develop a suitable dewatering procedure and

submit the same for Company's approval. The disposal of the water shall be performed such that

no harm is done to the environment and the dewatering procedure should indicate this safe

disposal methodology

4.3 Swabbing

The swabbing operation shall consist of running several suitable foam pig trains using air as

propellant through the pipeline. During swabbing operation, the residual free water content in the

pipeline shall be reduced to an acceptable lower value

lpg pipeline

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