Disclosure to Promote the Right To Information

Whereas the Parliament of India has set out to provide a practical regime of right to information for citizens to secure access to information under the control of public authorities, in order to promote transparency and accountability in the working of every public authority, and whereas the attached publication of the Bureau of Indian Standards is of particular interest to the public, particularly disadvantaged communities and those engaged in the pursuit of education and knowledge, the attached public safety standard is made available to promote the timely dissemination of this information in an accurate manner to the public.

इंटरनेट मानक

“!ान $ एक न' भारत का +नम-ण”Satyanarayan Gangaram Pitroda

“Invent a New India Using Knowledge”

“प0रा1 को छोड न' 5 तरफ”Jawaharlal Nehru

“Step Out From the Old to the New”

“जान1 का अ+धकार, जी1 का अ+धकार”Mazdoor Kisan Shakti Sangathan

“The Right to Information, The Right to Live”

“!ान एक ऐसा खजाना > जो कभी च0राया नहB जा सकता है”Bhartṛhari—Nītiśatakam

“Knowledge is such a treasure which cannot be stolen”

“Invent a New India Using Knowledge”

है”ह”ह

IS 15663-1 (2006): Design and installation of natural gaspipelines - Code of Practice, Part 1: Laying of pipelines[CED 7: Structural Engineering and structural sections]

IS 15663 (Part 1); 2006

ml C&h“*-H

Indian Standard

DESIGN AND INSTALLATION OF NATURAL GASPIPELINES — CODE OF PRACTICE

PART 1 LAYING OF PIPELINES

ICS 75.200

,,, ,

0 BIS 2006

BUREAU OF INDIAN STANDARDSMANAK BHAVAN, 9 BAHADUR SHAH ZAFAR MARG

NEW DELHI 110002

May 2006 Price Group -10

Structural Engineering and Structural Sections Sectional Committee, CED 7

FOREWORD

This Indian Standard (Part 1) was adopted by the Bureau of Indian Stmdarc@’ abr the drilfl fhdhed by the -\

Structural Engineering and Structural Sections Sectional Committee had beemapprovedbytlw C&n ~Division Council. ,.

Natural gas has been utilized in ‘the country for many years. With increased exploration efforts mtd dtanccdproduction, utilization of natural gas has also increased. Natural gas is considered to be much more ewhmwntfriendly and is therefore being preferred as an alternate i%el.Natural gas is envisaged to be an merging fhd in .

the country and is slated to cater to a major portion of the country’s energy requirement. The t&zation of natural I

gas is however largely dependent on an efficient transmission and distribution network through pipeline systetwqconnecting gas sources, gas production plants, process plants, storage facilities, to the userskcmsumers spread !

across long distances. Towards this objective of its efficient usage, there is a focus on development of pipeline

(

iintlastructure thrQugh extensive pipeline networks for transmission and d@ribution of natural gas in the country.

Considering the above, a need was felt to develop a standard that prescribes the requirements necessary for the .

safe design and installation of such pipelines and its testing and commissioning. The recommended actions setout in the standard are intended to protect the public life as well as the environment from possible hazards intransportation of.the gas. The recommendations are applicable to conditions that are normally encountered and /additional design considerations may be necessary where unusual conditions are encountered. This standard ispublished in three parts. The other parts m this series are: (

>Part 2 Laying of pipelines in crossings

Part 3 Pre-commissioning and commissioning of pipelines (a.The standards keep in view the practices in the country in the field and the safety considerations in following

..,,,

guidelines of the Oil Industry Safety Directorate:(

OISD-STD-141 Design and construction requirement of cross country hydrocarbon pipelines

OISD-STD-118 Layout of oil and gas installations

OISD-STD-117 Fire protection fiicilities for petroleum depots, terminal and pipeline installations \

Assistance have also been derived from the following International Standards:!

ISO 13623 Petroleum and natural gas industries — Pipeline transportation systems

AS~E B 31.8 Gas transmission and distribution piping systems

API RP 1102 Steel pipelines crossings railroads and highways

API 1104 Welding of pipelines and related facilities

Indian Standard

DESIGN AND INSTALLATION OF

IS 15663 (Part 1) :2006

NATURAL GASPIPELINES — CODE OF PRACTICE

PART 1 LAYING OF PIPELINES

1 SCOPE

The standard (Part 1) specifies the requirements andgives recommendations for the design, materials,construction and testing of pipelines made of steel andused in the transportation of natural gas and re-gasifiedliquid natural gas (RLNG). Specific requirements forlaying of pipelines in crossings (road, railway,watercourses, other pipelines, etc) are covered inIS 15663 {Part 2). The requirements for pre-commissioning and commissioning of pipelines arecovered in IS 15663 (Part 3).

The provisions of the standard apply to pipelines onland including pipelines up to and including isolationvalves of compressor station, prcrcess plant, liquidnatural gas terminals, etc and within the boundaries ofsuch facilities like sectionalizing valve stations,intermediate pigging stations, etc; that form part of thepipeline system connecting gathering stations or processplants to dispatch stations. The provisions in thestandard do not include the requirements of operationand maintenance of such pipelines. The scope of thestandard is also illustrated in Fig. 1 in Annex A.

The standard is not applicable for pipelines constructedfrom materials other than steel and for pipelines thatform part of distribution systems.

2 REFERENCES

The standards given below contain provisions whichthrough reference in this text, constitute provisions ofthis standard. At the time of publications, the editionsindicated were valid. All -standards are subject torevision and parties to agreements based on thisstandard are encouraged to investigate the possibilityof applying the most recent editions of the standardsindicated below:

Standard Title

IS 269:1989 Specification for ordinary portlandcement, 33 grade ~ourth revision)

IS 383: ‘1974 Specification for coarse and fineaggregates from natural sources forconcrete (second revision)

IS 456:2000 Code of practice for plain andreinforced concrete ~ourth revision)

Standard

1S 1489

(Part 1): 1989

(Part 2): 1989

IS 1498:1970

IS 1566:1982

IS 1978:1982

IS 8062:2006

IS 8112:1989

IS 15659

(Part 1): 2006

(Part 2): 2006

IS J 5663:2006

(Part 2): 2006

(Part 3): 200-6

API 1104:2005

API RP5LI :2002

API RP 5LW :1996

API 6D :2002

ASME B 16.9:2001

Title

Specification for portland pozzolanacement:

Flyash based (third revision)

Calcined clay based (third revision)

Classification and identification ofsoils for general engineeringpurposes @st revision)

Specification for hard drawn steelwire fabric for concretereinforcement (second revision)

Specification for line pipe (secondrevision)

Code of practic-e for cathodicprotection of buried pipelinesstructure for transportation of oil,natural gas and liquids

Specification for’’&3’~&.l wdin%jportland cement (first revision)

Specification for petroleum andnatural gas industries — Externalcoating for buried or submergedpipelines used in pipelinetransportation of gas and liquidhydrocarbons:

Ployolefin coatings (3-layer PE and3-layer PP)

Fusion bonded -epoxy coatings

Design and installation of natural gaspipelines — Code of practice:

Laying of pipelines in crossing

Pre-commissioning andcommissioning of pipelines

Welding of pipelines and relatedfacilities

Recommended practice for railroadtransportation of line pipe

Recommended practice for trans-portation of line pipe on barges andmarine vessels

Specification for pipeline valves

Factory made wrought steel buttweldIing fittings

1

1S 15663 (Part 1) :2006

Standard Title

ASMEB 31.8: Gas transmission and distribution2003 piping systems

ASME BPVC ASME Boiler and Pressure VesselCode

IIC :2004 Section H — Materials — Part C —Specification for welding rodselectrodes and filler materials

V :2004 Section V — Non-destructiveexamination

3 TERMINOLOGY

For the purpose of this standard the followingdefinitions shall apply.

3.1 Design Factor — Is a constant considered indetermining internal design pressure and is based onthe location class of a pipeline.

3.2 Design Pressure/Internal Design Pressure— Themaximum internal pressure for which the pipeline orits section is designed in accordance with therequirements of this standard.

3.3 Design Temperature

3.3.1 Design Temperature, Maximum — The highestpossible metal temperature during installation andoperation.

3.3.2 Design Temperature, Minimum — The lowestpossible metal temperature during installation andoperation.

3.11 Nominal Pipe Size (NPS)/Nominal Size — Isthe dimensionless designator of a pipe and is thestandard pipe size when followed by a number.

3.12 Nominal Wall Thickness — Is the wall thicknesscomputed by or used in design calculation.

3.13 Operating Pressure — Is the pressure at which apipeline is operated during normal operatirrg cycle, notexceeding the design pressure.

3.14 Pipeline — Those facilities through which naturalgas is transported, including pipe, pig traps, componentsand appurtenances up to and including isolation valves.

3.15 Pipeline Design Life — The period of timeconsidered for the purpose of verifying that areplaceable or permanent component is suitable for theanticipated period of service.

3.16 Pipeline System — Trunk pipelines up to andincluding isolation valves (of compressor stations,process plants, LNG treminals, etc), pressure controlvalves, flow control stations, metering, supervisorycontrol and data acquisition system (SCADA), safetysystems, corrosion protection systems, sectionalizingvalves, intermediate pigging stations, tap offs,receiving/despatch terminals and any other equipment,facility or building used in the transportation of naturalgas.

3.17 Processing Plant — Location where gas, ,isprocessed involving a change in its composition.

3.18 Regassified Liquid Natural Gas — The naturalgas obtained after gasification of liquid natural gas.

3.4 Despatch Station — Stations where gas is received 3.19 Right-of-UseKlght-of-Way — The corridor ofand dispatched to pipeline system or consumer. hind within which the pipeline operator has the right to

3.5 Gas Gathering Station — Station where gas is conduct activities in accordance with the agreement

gathered from various wells/sources. with the land owner.

3.6 Hydrostatic Test Pressure — The pressure at 3.20 Sectionalizing Valve Station — A valve s~tion

which hydrostatic test is conducted on a section of a in a main pipeline system installed to isolate a particular

pipeline. pipe section whenever needed.

3.7 Intermediate Pigging Station — An intermediate 3.21 Specified Minimum Yield Strength (SMYS)—Is the minimum yield strength required by thestation used for launching and receiving of~igs for

cleaning and health monitoring of pipeline system. specification or standard under which the material ispurchased.

3.8 Location Class — The geographical area alongthe pipeline classified according to criteria based onpopulation density and human activity (present andanticipated for future).

3.9 Maximum Allowable Operating Pressure(MAOP) — The maximum pressure at which thepipeline system is allowed to be operated. The MAOPis less than or equal to the design pressure.

3.10 Nominal Outside Diameter — Is the as producedor as specified actual outside diameter of the pipe.

4 PUBLIC SAFETY, PROTECTION OFENVIRONMENT AND STATUTORYREQUIREMENTS

The pipeline should meet the requirements of safety,health and environment in accordance with applicablestatutory/regulatory requirements. The effect of thepipeline on the environment along its route shall betaken into consideration while planning, in designing,during construction and for intended operation.Appropriate authorizations shall be obtained from the

2

landowners and appropriate authorities as applicable,including other utilities being affected by the pipelinesystem. For safety in construction the applicableguidelines of Oil Industry Safety Directorate shall becomplied with. Applicable statutory/regulatoryrequirements have been “listed in Annex B forguidance.

5 PIPELINE DESIGN

5.1 General

5.1.1 The pipelines shall be designed in a manner thatensures adequate public safety under all conditionslikely to be encountered and to withstand all installation,testing and operating conditions/loads. All necessarycalculations shall be carried out to veri~ structuralintegrity and stability of the pipeline for combined effectof pressure, temperature, bendhrg, soil-pipe interaction,external loads and other environmental parameters asapplicable. Such calculations shall include but not belimited to the following

a)

b)

c)

d)

Buoyancy control and stability analysis forpipeline section to be installed in areassubjected to flooding/submergence,

Crossing analysis of rivers by trenchlesstechniques, wherever soil data is favorablefor such operation,

Pipeline expansioticontraction and its effecton station piping (above ground), and

Evaluation of potential for earthquakeoccurrence along pipeline route and carryingout requisite seismic analysis to ensure safetyand integrity of the pipeline system.

5.1.2 A significant factor contributing to the failureof a pipeline i: the damage caused to the pipeline byactivities along the route of the pipeline. associatedwith human dwellings and commercial/industrialinstallations. Pipelines and its associated facilitiesare designed to meet the requirements of LocationClass, based on the degree of exposure of the pipelineto such damage. The design of the pipeline is relatedto the Location class by an appropriate design factor(see 5.3).

5.1.3 The pipelines shall be normally designed for anassumed economic design life of 30 years. The pipelinesare designed for the following operating temperature1imits:

a) above ground: 65°C maximum and –28°Cminimum

b) below ground: 60”C maximum and –28°Cminimum.

IS 15663 (Part 1): 2006

5.2 Suwey

5.2.1 Route Selection

Route selection shall take into account the design,construction, operation and maintenance of the pipelinetaking the following into consideration:

a)

b)

c)

d)

e)

o

@

safety of public and personnel working on ornear the pipeline;

protection of environment, other properties andfacilities; including electrical interferences;

third party activities;

geotechnical and hydrological conditions;

requirements of construction, operation andmaintenance of the pipeline;

fiture explorations and de~elopmental plans;

existance of archeological/historical monu-ments, reserved forests, national parks, etc.

In order to ensure adequate safety to public, whereverpracticable, pipelines should avoid built-up areas orareas having human activities. The applicable safetyrequirements as given in this standard and those ofother statutory requirements shall be followed.

5.2.2 An assessment of the environmental impact ofthe pipeline shall also be made, giving considerationbut not limited to the following requirements: ‘”

a) temporary works to be undertaken duringconstruction and repair,

b) effect of the pipeline, and

c) effects of any possible loss of gas.

5.2.3 The impact on other facilities along the pipelineroute shall also be determined and evaluated with theowners of such facilities. Any third party activity alongthe route shall be identified and evaluated inconsultation with the parties concerned. Adversegeotechnical and hydrological conditions shall also beidentified along with measures to address the same.The route selected shall also permit access and the spacerequired for carrying out construction, testing,operation and maintenance of the pipeline. Route andsoil surveys shall be carried out to identi& and locatethe relevant geographical, geological, and environ-mental features and other facilities such as otherpipelines, cables, obstructions and crossings that couldhave an impact on the pipeline.

5.2.4 Determination of Location Class

When survey is performed for gas pipelines, the classlocations based on population density index shall berecorded. along.with chainages at change points of eachclass location. Population density index along thepipeline route shall be determined in accordance withthe procedure given in kUEX C.

3

IS 15663 (Part 1) :2006

5.3 Design Factor and Location Classes

Pipelines shall be designed using the design factors foreach designated location class and the type of facilityas given in Table 1.

5.4 Loads

5.4.1 General

The pipeline shall be designed to withstand al\ loadsthat are likely to be encountered in its installation,testing, crperaticmand maintenance.

For the_purpose of design, loads shall be classified as:

a) operational loads,b) environmental loads,c) construction loads, andd) accidental loads.

5.4.1.1 Operational loaa%

Loads from the intended use of the pipeline shall beclassified as operational loads. These shall include theloads fkom the self weight of the pipeline, loads due tointernal pressure and temperature of gas beingtransported, loads from soil cover, external hydrostaticpressure, reaction forces at supports tiom operatingloads, surge, etc.

5.4.1.2 Environmental loaa3

Loads arising from the environment shall be classifiedas environmental, unless these are to be considered asoperational or as accidental. Loads from winds,earthquake, snow, trafilc, etc, are considered asenvironmental loads.

5.4.1.3 Construction loads

Loads arising from the installation and pressure testingof the pipeline system shall be considered asconstruction loads. These will include loads arisingfrom transportation, handling, storage, construction andpressure testing.

5.4.1.4 Accidental loads

In addition possible loads ffom fire, explosion, fallingobjects, landslides, equipments, etc, that are possiblebut the occurrence of which.has low probability shallalso be taken into consideration as accidental loads.

5.4.1.5 Combination of Ioaak

While designing the pipeline the most urtfavourableload combination from operational, environmental,construction and accidental loads, that is, likely to occursimultaneously shall be considered.

5.4.2 Internal Design Pressure

The internal design pressure at any point in the pipeIinesystem shall be equal to or greater than the maximumallowable operating pressure (MAOP).

The internal design pressure shall be determined fromthe following:

[1P= ‘St~ F.E.T

where

D

E

F

T

s

.

.

.

=

.

specified outside diameter-of the pipe, in m,

longitudinal joint factor, which for electricresistance welded (ERW), longitudinal seamsubmerged arc welded (LSAW), helicalseam submerged arc welded -(HSAW) andseamless types of pipes, manufactured inaccordance with IS 1978 shall be consideredas 1;

design factor obtained from Table.1;

temperature derating “factor, which for thetemperature conditions defined in thisstandard (see 5.1.3) shall be considered as 1;

specified minimum yield strength (SMYS)in N/mm* of pipe material;

Table 1 Design Factor for Pipeline Construction

(Clause 5.3)

sl Facility Location ClassNo. ~e \

class 1 class 2 class 3 class 4

(1) (2) (3) (4) (5) (6)

i) Main pipelines 0.72 0.6 0.5 0.4ii) Station piping 0.5 0.5 0.5 0.4iii) Watercourse (Mver/strearn) crossing, trenchless or 0.6 0.5 0.4 0.4

open cutiv) Cased/uncased crossings or parallel encroachments on 0.6 0.5 0.5 0.4

right-of-use of hard surfaced roads, pubtic streets andhighways

@ Rail crossings 0.5 0.5 0.5 0.4vi) On bridges 0.4 0.4 0.4 0.4

4

r = nominal wall thickness, in mny and

P = internal design pressure, in N/mmz.

5.5 Strength Requirements

5.5.1 Determination of Stresses

5.5.1.1 Hoop stress due to gas pressure

The hoop stress due togas pressure shall be calculatedfi-omthe following:

s,, =P.(D-2tMn)

2. tMn

where

s,, =p.

D=

t%=

circumferential hoop stress due to gas,

internal design pressure,

specified outside diameter, and

specified minimum wall thickness.

NOTE — The specified minimum wall thickness is thenominal wall thickness less the allowance for corrosion.

5.5.1.2 Other stresses

The longitudinal, shear, bending, torsional and otherstresses shall be calculated taking into account thestresses ti-om all relevant loads as mentioned in 5.4.The stress analysis shall be carried out in accordancewith the appropriate provisions in 833, 834 and 835of ASME B 31.8. For terminal pipe work, flexibilitystress analysis shall be carried out in accordancewith 5.5.1.2.1.

5.5.1.2.1 Flexibility stress analysis

While designing the pipeline due consideration shallbe given to the prevention of excessive stresses due tothermal expansion or contraction by providingadequate flexibility in the pipeline system. It shall beensured that such flexibility consideration does notcause excessive stresses or loads at the pipe joints, atconnections or at anchorage points. In designing forflexibility, the pipeline shall be treated as a whole anddue consideration given to restraints in the pipelinesystem. Flexibility shall be provided by means ofbends, loops, offsets, use of expansion joints, use ofcouplings, etc. Wherever required, the adequacy offlexibility provided in the pipeline shall be establishedthrough appropriate design calculations. The flexibilityrequirements specified in ASME B 31.8 shall alsoapply.

5.5.2 Strength Criteria

5.5.2.1 General

Pipelines shall be designed against failures in yielding,fatigue, ovality and fracture toughness.

IS 15663 (Part 1) :2006

5.5.2.2 Yielding

The maximum hoop stress due to gas pressure shallnot exceed

Sb < ~E.s

where

s=E=

F=

specified minimum yield strength (SMYS),

longitudinal joint factor as defined in 5.4.2,and

design factor obtained from Table 1.

5.5.2.3 Fatigue

Fatigue analyses shall be carried out on pipelinesections that may be subject to fatigue from cyclic loadsin order to:

a) Demonstrate that initiation of cracking willnot occur; or

b) Define requirements for inspection forfatigue.

Fatigue analyses shall include a prediction of range ofload cycles into nominal stress or strain range.

The effect of mean stress, internal service, externalenvironment, plastic prestrain and number of loadingcycles during lifetime shall be accounted for whendetermining fatigue resistance. ,,, >

The selection of safety factors shall take into accountthe inherent inaccuracy of fatigue-resistancepredictions and access for inspection for fatiguedamage. It maybe necessary to monitor the parameterscausing fatigue and to control possible fatigue damagecontrol accordingly.

5.524 Ovality

Ovality that can cause buckling or interference withpigging operations, shall be avoided.

5.5.2.5 Fracture toughness

Fracture toughness requirements shall be met in thematerial being used in the pipeline and by selectingappropriate materials that satis~ the requirements offatigue toughness stipulated inASMEB31.8.

5.6 Stability

Pipelines shall be-designed to prevent horizontal andvertical movement, or shall be designed with sufficientflexibility to allow movements within the strengthcriteria being fulfilled. The following shall beconsidered for stability:

a)

b)

wind loads;

axial compressive forces at bends and lateralforces at branch connections;

5

IS 15663 .(Part l).: 2006

c)

d)

e)

o

g)

lateral deflection due to axial compressiortloads in the pipelines;

exposure due to erosion;

geotechnical conditions including soilinstability due to seismic activity, groundwater level, etc;

construction methods; and

trenching and/or backfilling.

5.7 Pipeline Spanning

Spans in pipelines shall ensure compliance with thestrength requirements in 5.5. The following shall alsobe taken into consideration.

a) support conditions,

b) interaction with adjacent spans,

c) possible vibrations due to wind,

d) axial forces in the pipelines,

e) soil properties and soil erosion, and

f) effects from other activities,

.5.8 Additional Requirements

5.8.1 Protection of the pipelines from the followingshall be considered:

a) effects of pipeline damage on safety andenvironment;

b) effects of interference tlom other activities;and

c) requirements of public safety and protectionof the environment.

NOTE — Activities to be considered for this purpose shallinclude other land users, traffic, cultivation, drainageinstallations, building construction and work on roads,railways and waterways.

5.8.1.1 The requirements for protection of pipelinesshall form a part of the safety evaluation in 4, whererequired.

5.8.1.2 Markers shall be erected at road, rail and canalcrossings and elsewhere, to enable other users of thearea to identi~ the location of the pipeliies.

NOTE — Protectionofpipelinesshallincludeincreasedwalltlickness,cover,mechanicalprotection,controllingaccessto-pipelineroute,markers,or a combinationof thesemeasures.

5.8.2 Pipeline Cover

The pipeline shall be buried normally at a depth of1.0 meter except at watercourse/rail/road crossingswhere minimum cover shall be as given in Table 2.Increased walI thickness and cover shall be providedat critical locations and crossings.

5.8.2.1 Additional soil cover other than that specifiedabove shall be provided at locations indicated bystatutory/local authorities or in areas likely to have an

.,,

Table 2 Minimum Cover Requirements for Pipelines

(Clause 5.8.2)

S1No. Locations Mhrimum Coverm

(1) (2) (3)

Oii)

iii)

iv)

v)vi)

vii)

viii)

ix)

x)

Areas of agricultural, horticulturalactivity urrdof limited or no human activityIndustrial, commrxcird and residential area

Rocky terrain

Drainage, ditches at roadskailway crossing

Minor river crossings/canrdldrain/naltJdltches

Major river crossings (below scour Ievcl)

River with rocky bed (below scour level)

Area under influence of tides

Cased/Uncased road crossingCased railway crossing

1.01.0.1.0

1.21.5

2.5

1.51.5

1.21.7

NOTES

1 The depth of cover shall be measured from the top of the pipe coating to the top of the undisturbed surface of soil-or the top of gradedworkhg strip, whichever is lower. The till material in the working strip shall not be considered in the depth of cover.

2 The cover shall be measured from the top of road or top of rail, as the case.may be.

3 For river/watercourses that are prone to scour and erosion, adequate safe cover shall be provided below the predicted scour profileexpected during the life time of the pipeline.

4 When scour level is not known, an additional cover of 1 m shall be provided from tbe existing bed of the river/watercourse.

5 The minimum cover requirements shall be applicable forall Location Classes.

6 Whenever the above provisions of cover cannot be provided due to site constraints, additional protection in form of casings, bridging,etc, shall be provided.

6

increased risk of impact damage or third partyinterference.

5.8.3 Pipe Wall Thickness

Pipe wall thickness calculations shall be carried out incompliance with this standard and a corrosionallowance as per the requirements of the owner of thepipeline shall be added to the calculated thickness. Pipethickness shall be checked and revised as required tominimize the number of field hydrostatic testingsections, considering combined testing of pipes indifferent class locations. In addition the selectedthickness shall also be checked to ensure that thediameter to thickness (D’t) ratio does not exceed 70 inorder to avoid damage to pipe during handling andtransportation, unless the pipes are loadedhransportedin accordance with API RP 5L 1 or API RP 5LW; or thepipeline shall be hydrostatically tested for at least 2 hat a minimum pressure of 1.25 times the designpressure for pipelines installed in Location Class 1areas -and for a minimum pressure of 1.5 times thedesign pressure if the pipelines are installed in Location.Class 2, 3, or 4 -areas.

5.8.4 CIearance Between Pipelines/Mains and OtherUnderground Structures

5.8.4.1 A clearance of at least 150 mm shall beprovided between a buried pipeline and otherunderground structure not used in conjunction with thepipeline. Wherever such-clearance cannot be provided,adequate precautions to protect the pipeline by meansof c-asing, bridging, or insulating material shall beensured.

5.8.4.2 In laying parallel pipelines in the same trench,the minimum clear distance between the pipelines shallbe 500 mm.

5.8.4.3 The ‘location of a new underground pipeline,-when running parallel to an existing undergroundpipeline shall beat a minimum clear distance of 5 m.Wherever such clearances cannot be provided,adequate precautions to protect the pipelines by meansof casing or insulating material shrill be ensured.

5.8.5 Additional Design Considerations for Piping forDispatch Stations, Tap-Off Stations and ReceivingStations

5.8.5.1 All piping and equipment shall be designed inaccordance with the provisions of this standard. Allpiping materials shall be as in 6.2, Utility piping to beprovided shall be designed in accordance with theprovisions in 5. Design shall provide consideration forall loadings like weight, temperature, etc, that maysignificantly induce stresses in the pipe material inaddition to fluid pressure.

IS 15663 (Part 1): 2006

5.8.5.2 PipingJexibility/stress analysis

All piping shall be designed for thermal expansionunder start up, operating and shut down conditionswithout over stressing the piping, valves or otherequipment. Provisions for expansion shall normallybe made with bends and offsets. All piping shall beadequately supported, guided or anchored so as toprevent undue vibration, deflection or loads onconnected equipments. Equipments/valves requiringperiodical maintenance shall be supported in such away that the valves and equipment can be removedwith minimum temporary pipe supports.

5.8.5.3 Piping layout

Wherever possible, piping shall be located above theground, Piping shall be designed considering skintemperature of piping material under empty conditionsm 65°C or the design temperature of pipeline,whichever is higher. Wherever felt necessary, stressanalysis shall be carried out in order to determine theallowable pipe movement and support requirements.Buried piping inside the terminal area shall have aminimum depth of cover of 1.2 m. Where buried pipescome out of the ground, the underground coating onthe pipe will continue for a length of at least 500 mmabove ground. Platforms and crossovers shall beprovided for ease of operation and maintenance. ‘‘”

5.9 Hydrostatic Pressure Test Requirements

Pipelines shall be hydrostatically tested in place afterinstallation and before putting into operation fordemonstrating their strength and leak tightness.Prefabricated sections and tie-in se@ions maybe pre-tested before their installation.

5.9.1 Test Medium

Pressure tests shall be conducted with water (if requiredwith inhibited water), except when ambienttemperature conditions prevent testing with water.Pneumatic tests may be carried out with air or a non-toxic gas in such instances, for a limited section of thepipeline employing adequate safety, with testconditions as agreed to between the owner and theconstruction agency.

5.9.2 Test Pressure and Test Duration

5.9.2.1 The minimum hydrostatic pressure in anysection shall be as given in Table 3. The maximumhydrostatic pressure shall not however exceed thepressure required to produce a hoop stress equal to95 percent of SMYS of the pipe material based onminimum wall thickness in the test section. The testduration shall be a minimum 24 h. Mainline valves shallbe installed after successfid completion of hydrostaticpressure testing. All sections that have been previously

7

IS 15663 (Part 1) :2006

hydrostatically tested, namely, road/rail and rivercrossings, may be retested along with the completemainline sections.

. Table 3 Test Pressure Requir-ements

(Clause 5.9.2.1)

S1No. Location Class Pressure Requirement

(1) (2) (3)

i) 1 1.25 x Design Pressureii) 2 1.25 x Design Pressureiii) 3 1.40 XDesign.Pressureiv) 4 1.40 XDesign Pressure

5.9.2.2 Hydrostatic pressure testing of terminals shallbe carried out separately. Pneumatic test at 5 kg/cm2shall be carried out prior to hydro test of terminals for aminimum period of 30 min for the purpose of detectingany leakages in gaskets/joints. Dispatch/Receiptterminals as well as other intermediate facilities shallbe tested at 1.4times the design pressure. The hydrostaticpressure test duration shall be for a minimum of 4 h.

5.9.3 Acceptance Criteria

Pressure variations during testing shall be acceptable,if caused by factors other than leakage, like temperaturevariations.

Pipelines not -meeting the requirements shall berepaired and retested in accordance with therequirements of this standard.

5.10 Design for Pigging

The pipelines shall be designed to meet therequirements for pigging considering the following:

a)

b)c)

d)

e)

f)

g)

h)

j)

k)

m)

location of the permanent pig traps orconnections for temporary pig traps;

access to the pig traps;

handling facilities;

isolation requirements necessary for piglaunching and receiving;

venting and draining requirements for pre-commissioning and operation;

direction of pigging including hi-directionalpigging;

minimum permissible bend radius and thedistances between bends}fittings;maximum permissible changes in diameterand tapering requirements at internal diameterchanges;

tittings/branch connections and compatibilityof linepipe material;

internal coatings; and

pig signalers.

The safety of access routes and adjacent facilities shall

be considered when determining the orientation of pigtraps.

5.10.1 Scraper Traps/Scraper Barrels

Scraper traps/scraper barrels shall be provided at thedispatch, and receiving terminals. The scraper trapsshall be capable of handling intelligent pigs and othercleaning pigs. All anticipated pigging operations,including possible internal inspection shall beconsidered when determining the dimensions of traps.The launching and receiving barrels and its closuresshall be designed in accordance with the requirements.ofthis standard. Adequate arrangements for launching,retraction, handling and lifting of cleaning andinstrumented pigs shall be provided at the scraperstation. These stations shall be provided with accessroad from the nearest metal road. Corrosion resistantcoating shall be provided on the pipeline up to aminimum length of 500 mm after it comes aboveground/before it gets buried underground at terminaland scraper stations. The traps shall be pressure testedin accordance with 5.!3.

The diameter of traps of the launcher shall be suitablefor uni-directional/bi-directional traps. Centre-lineelevation of scraper trap shall be at suitable height fromgrade level. Suitable arrangements shall be providedfor handling and lifting of pigs. Traps shall beaccessib~e by walkway lroad for movement ‘ofequipment, pigs, etc.

5.10.1.1 The piping system at the terminals andintermediate stations shall be designed to havesufficient flexibility to prevent pressure and thermalexpansion or contraction from causing excessivestresses on the connected equipment. Installation ofanchor block in the underground pipeline shall not bepermitted. If required adequate length of trench inapproaches to stations shall be provided with a selectbackfill to ensure flexibility.

5.10.2 Pig Signalers

At least two pig signalers, one on the trap and one onthe pipe (above ground) shall be provided. Pig signallershall be hi-directional type with trigger mechanism,suitable for maintenance with pipelineunder operatingpressure. Operational access shall be provided for allpig signalers installed on buried pipeline sectionswithin the boundaries of the station.

5.11 Section Isolation Valves and Valve Stations

5.11.1 Section isolation valve stations shall be providedfor isolating sections of pipeline in order to:

a)

-b)

Limit the hazard and damage from accidentaldischarge from pipeline system; and

Facilitate maintenance of pipeline system.

8

5.11.1.1 Section isolation valves shall be installed atbeginning and end of a pipeline and where requiredfor operation and maintenance and control ofemergencies. Factors such as topography of thelacation, ease of operation and maintenance includingrequirements for pressure relief, security, proximityto occupied buildings shall be taken into considerationin deciding the location of the valves. The maximumdistance between the location of any two sectionisolation valve stations shall be as given below, basedcm the location class and taking into considerationfactors like the terrain features, requirement of safety

and operation, etc.

Location Class Maximum Distancekm

.1 322 24

3 164 8

The valve stations shall be located at a readilyaccessible location such as near roads and shall beprovided with an access road from the nearest allweather metalled road. The facilities within valvestation shall be secured by providing a suitableenclosure with gate. The location of valve station shallbe clear of overhead power lines. Pipeline to be locatedwithin the section isolation valve station limits shallbe of wall thickness appropriate for the applicableLocation Class, but in no case shall be less than thatapplicable for Location Class 3. The provisions ofremote operated feature shall be as per the operationand control philosophy to be adopted for the project.At locations where valve stations are combined withcompressor/repeater stations, the requirements of safedistance and statutory clearance, as applicable, shallbe followed.

5.11.2 Valve shall be installed buried and providedwith a stem extension in such a way that the centre ofactuator is at approximately 1.0 m above the finishedground level. Section isolation valve on the mainpipeline shall be ball valves of fill bore type, to allowsmooth passage of cleaning and intelligent pigs.Pipeline sectionalizing valve may be either gas actuatedor manually/electrically/pneumatically/hydraulicallyoperated and with butt-welding ends. Valve surfaceshall be provided with corrosion protection coating.Valve body vent and drain lines shall be extended andterminated above ground.

6 MATERIALS ~

6.1 General

Materials for use in the pipeline system shall:

a)

b)

c)

IS 15663 (Part 1): 2006

have the mechanical properties necessaryto comply with the design requirementsspecified in-5,

have necessary properties to comply withthe requirements for corrosion controlspecified in 6.8.1.2, and

be suitable for the intended fabrication andor construction methods.

6.2 Line Pipes

Line pipe shall conform to IS 1978. The material forstation piping shall also conform to IS 1978 orequivalent.

6.3 Bends

Bends may be made.fi-ompipe material complying withthe mechanical properties of the line pipe. Bends shallsatis& the requirements of minimum wall thicknessof the adjacent piping. The minimum radius of coldfield bends shall be as given below

Nominal Pipe Size Minimum Radius of Bend

NPS 12 and below 21 D

NPS 14 and up to and 30 Dincluding NPS 18

NPS 20 and above 40 D

Where, D is the specified outside diameter of the pipe.

For underground pipeline not subjected to intelligentpigging, bends of radius of 1.5 -times the specifiedoutside diameter of pipe may be used. Long radiusbends of a minimum radius of 5D may be used forpipelines subjected to intelligent pigging. Mitres shallnot be permitted in the. field for change of direction.

6.4 Valves

6.4.1 The application of various types of valves shallbe as follows:

Valve Type Typical Application

Globe/Plug ThrottlingBall On/off, Isolation (on main line)Check Uni-directional flow

6.4.2 All pipeline valves shall conform to therequirements of API 6D or equivalent. Ball valves formain line shall have primary metal seat design. In orderto minimize potential leak sources, valves used inmainline shall be with butt-weld ends. Flanges maybeused where frequent access or removal of equipmentis required. Valves used in buried portion shall be withbutt-weld joints only, except at the locations where hottapping operation is to be carried out for which, buriedflanged end valve may be provided.

9

IS 15663 (Part 1): 2006

6.4.2.1 Wherever underground valves are provided,these shall be provided with a stem extension in sucha way that the centerline of the rim of the hand wheelon a horizontal shaft or centre of power actuator is

. approximately 1.0 m above the finished ground level.Valve surface shall beprovided with suitable corrosionprotection coating.

6.5 Branch Connections

Minimum size of any tapping from the undergroundpipeline shall be of 50 mm nominal bore and shall beprovided with an isolation ball valve located at aminimum distance of 50 mm from the pipeline. Allbranch connections or side tap on the piggable lineshaving branch line diameter equal to or exceeding40 percent of the main pipe diameter, shall be providedwith flow tees/bar tees in order to enable smoothpassage of cleaning, gauging, instrumented and otherpigs. All flow tees/bar tees shall comply with therequirements of ASME B 16.9.

6.6 Insulating Joints

Insulating joints shall be provided to electrically isoIatethe buried -pipeline from above ground pipeline.Insulating joints shall be monolithic type and shallallow smooth passage of pigs. Insulating joints shalleither be installed in above ground portion of thepipeline, immediately after the buried/above groundtransition at the scraper stations or in buried portion atunderground pipeline.

6.7 Fittings and Flanged Connections

The fittings and flanged connections shall complywith the appropriate requirements specified inASME B 31.8.

From the launcher/receiver to the mainline, the fittings/flange connections shall match the strength of the mainline.

6.8 Coatings

All coatings shall cover the following requirements:

a)

b)

c)

d)

e)

f)

g)

h)

type of the coating

thickness of the individual layers of coatingand its total thickness;

composition of the coatinghase material;

mechanical properties;

temperature limitations in use;

surface preparation requirements;

adhesion requirements; requirements formaterials, application and curing, includingpossible requirements for health, safety andenvironmental aspects; and

requirements for testing and inspection, andrepair procedures where relevant.

6.8.1 External Coatings

6.8.1.1 Concrete weight coating

6.8.1.1.1 Materials

33 -grade Ordinary Portland Cement conforming toIS 269 or 43 grade Ordinary Portland Cementconforming to IS 81-12or Portland Pozzolana Cementconforming to 1S 1489 (Part 1) or IS 1489 (Part 2)shall be used.

Aggregates shall comply with the requirements ofIS 383.

Water used in concreting shall preferably be limpid,fresh and clean and.shall be free from injurious amountsof oils, acids, alkalis, salts, sugar, organic materials orother substances that may be deleterious to concreteor steel. Water shall not contain salts of chlorides,sulphates and magnesium.

Reinforcement used shall consist of welded steel wirefabric manufactured in flat sheets or in rolls (ribbonmesh) and shall conform to IS 1566.

6.8.-1.1.2 Coating requirements

The compressive strength of concrete shall not be lessthan 20 Mpa at 28 days and 13.5 Mpa at 7 days andthe concrete mix shall meet the requirements of IS 456.

Concrete shall be applied by casting or by usingimpingement method. The equipment for such purposeshall be capable of concreting with a reasonable degreeof uniformity in thickness, densi~ and strength.

6.8.1.1.3 Placing of reinforcements

Prior to placing of reinforcement, the pipe protectivecoating shall be carefully inspected and repaired ifnecessary and shall be free from foreign matters. Thereinforcement shall protrude a minimum 50 mm fromthe finished concrete coating and shall rest on syntheticresin spacers or precast cubes. For concrete thicknessup to 50 mm, the reinforcement shall be placed in asingle layer in-the middle. For thickness of more than50 mm, the reinforcement shall be placed in two layersequally distributed. If application method requires morethan one pass of concrete, one layer of reinforcementshall then be placed for each pass of concrete.

6.8.1.1.4 P/acing of concrete

“Forconcreting by impingement method, the placementof concrete to the specified thickness shall be in onecontinuous operation. Coating shall be bevelled to aslope of 2:1 and shall terminate about 50 mm from theend of anti corrosion coating.

6.8.1.1.5 Curing

Curing shall either be by moist curing or ‘by using

10

curing membranes. In the case of moist curing, the pipesurface shall be kept wet during day light hours for atleakt seven days after application of the concretecoating and the concrete coating shall not be allowedto dehydrate. In the case of membrane curing, thecuring shall be performed by application of anapproved curing membrane using sealing compounds,immediately after concrete coating. When membranecured, the pipe shall not be transported for a period ofat least four days tlom the date of concreting.

6.8.1.1.6 Tolerance in thickness and weight

Maximum variation in coating thickness checked atleast at three points on-the surface shall be 8 mm. Thevariation in weight shall be +5 percenti-2 percent ofthe calculated theoreticiil weight. Each pipe shall beweighed in dry condition prior to shipment and afier28 days of placing of concrete. The weight shall bemarked on the inside of the pipe.

6.8.1.1.7 Inspection and test

Non-destructive tests like ringing, shall be carried outfor all coated pipes to detect any darnages which is tobe repairedtrecoated as found necessary. Check shallalso be done by megger or equivalent device for eachcoating to verifi insulation between reinforcement andpipe.

6.8.1.1.8 Concrete coating offleld wela3

Uncoated pipe surface at field welds should be concretecoated. Method for concreting shall be same as for mainline pipe.

6.8.1.1.9 Repairs in concrete coating

Repairs in concrete coating shall be permitted for thefollowing:

a) Unavoidable damage in handling and instorage; and

b) Spalling (that is, loss of concrete ofmore-than25 percent of the total thickness). Damage dueto spalling of an area of more than O.lmz andless thrmO.3 mz, the concrete shall be removedand repaired in accordance with an approvedprocedure.

6.8.1.1.10 Precautions in unloading, storing andhauling

During the operations of loading, unloading andstock-piling, the pipe sections shall be handled in sucha way so as to avoid dents, cuts, cracks and otherdarnages especially at b.evelled ends or damages toconcrete coating. Stacks shall consist of a limitednumber of layers such.that the pressure from the self-weight of the pipes do not -cause damage to thecoating.

IS 15663 (Part 1): 2006

6.8.1.2 External corrosion prevention

The external coating shall be provided to pipeliies tomitigate corrosion. The external coating provided shallsatis@ the following factors:

a)

b)

c)

d)

e)

o

g)

h)

provide adequate electrical resistance;

be effective in preventing ingress of moisture;

provide adequate adhesion between the pipemetal and the coating;

should not be susceptible to cathodicdkbondmen~

shall have adequate resistance to agein-g,brittleness and cracking;

shall provide adequate shear resistancebetween the coating and other additionalcoating, environment or insulation;

shall not have detrimental effect on the pipemetal; and

shall not be easily damaged in handling,transportation, storage and installation of pipe.

6.8.L2.I Fieldjoint coating of corroswn coating

The field joints shall, be protected with a -coatingmaterial, that is, compatible with the line pipe material.The coating shall be such that it can be easily appliedin field conditions. The coating can be carried out ,withheat shrhk wrap around sleeves or cold tape or anyother suitable type of coating with muturd agreementbetween owner and construction agency afterascertaining its suitability for the-purpose. The coatingshall conform to the requirements of IS 15659 (Part 1)and IS 15659 (Part 2).

6.8.1.2.2 Coating for prevention of corrosion

Pipeline coating for external corrosion protection shallmeet the requirements of IS 8062. Catho&c protectionprovided shall meet the requirements of IS 8062. Allpipelines above ground level and structures shall besuitably painted to prevent atmospheric corrosion andas per environment requirement. Unless specifiedotherwise, the painting shall ensure protection innormal corrosive environment.

7 CONSTRUCTION

7.1 Construction Plan

A construction plan shall be prepared beforecommencement of construction to assist in control ofthe work. The plan shall contain a description of theconstruction; the health, safety and environment plw,and the quality requirements. The description of theconstruction should include methods, personnel andequipments required for the construction and workingprocedures. The health, safety and environment planshould describe requirements and measures for the

11

IS 15663 (Part 1) :2006

-protection of the health and safety of the public andpersonnel involved in the construction and theprotection of the environment. It should contain the

. applicable statutory and regulatory requirements,identification of hazards and measures required fortheir control and procedures for handling emergencysituations.

All facilities, which may include existing roads andrailways, rivers/canals, footpaths, pipelines, cables andbuildings; that may be affected by the construction ofthe pipelines shall be identified prior to the beginningof the work. Temporary provisions and safety measuresnecessary to protect the identified facilities duringconstruction .should be established.

7.2 Preparation of Route

7.2.-1Site Inspection

Before the commencement of construction work, siteinspection of the existing conditions along theworking width of the pipeline route shall beundertaken after access to the route has been grantedto ascertain facilities that would potentially getaffected by construction activity and to obtain mutualapproval of all parties/authorities concerned. Theunderground utilities in the pipeline route may bedetected using tools like cable locators, groundpenetrating radar, etc, to avoid accidental damagesand safety of personnel.

7.2.2 Surv@ and Marking

7.2.2.1 Topographical survey shall be carried out alongthe pipeline routefor locating the centre-line of pipelinealignment cm the ground, constructing surveymonuments, for field measurements, for planimetryand profiles and for the preparation of drawings anddocuments. Soil investigation for the purpose of visualengineering classification of soil along the pipelineroute shall also be carried out. While undertaking thesurvey, the class location based on the populationdensity index shall also be determined in accordancewith 5.2.4. Work shall be performed by or under thesupervision of a qualified land surveyor.

A preliminary survey for locating the .centre-line ofpipeline alignment on the ground and for identifyingexisting features or obstructions along the route shallbe carried out. While locating the centre-line of thepipeline, archeological sites, reserved forests,environmentally sensitive areas, mining sites and builtup areas shall be avoided.

7.2.2.2 The pipeline defining trench centre-line shallbe staked by placing suitably painted marker stakes atTurning Points (TPs) and.at Intermediate Points (IPs)between consecutive TPs. Staking shall normally bedone at intervals of 500 m along the centre-line of the

pipeline. Stake markers shall be placed in the centre-line of the pipeliie at dktances of maximum 500 m forstraight sections and at a maximum of 30 m ofhorizontal bends, but in no case less than at the centreof bends. Change in direction of line shall be markedon the TP marker stakes. Each stake marker shall carrya unique identification number, which shall be separatefor TPs and IPs.

Permanent Bench Marks (BM) at approximately every5 km or permanent structures on or off the Right-of-Use (ROU) shall be established and described.

The pipeline alignment shall run clear of the existingmonuments, properties and structures as indicated inPipeline Route Survey Data Sheet (Annex D).

7.2.2.3 Azimuth checks with respect to sun or polarisshall be carried out at intervals of 15 to 20 km.

7.2.2.4 Alignment of crossings

As far as possible, crossings shall be made at rightangles. The angles of crossing for all fences, propertylines, utilities, roads, railways, canals, streams, etc, thatare crossed shall be established. In addition, the &uebearings of the center-line of the road, railway, water-course (canals, streams, rivers), as well as that of thepipe centre-line shall also be determined. TurningPoints (TPs) provided near crossings shall be locatedat least 50 m from the boundary of the crossings, oiistable and fw ground.

The angles for all railway crossings shall be as closeto 90° as possible, but in no case less than 85° to thecentre-line of the railway..

The angle of crossings for national and state highwaysshall be as close to 90° as possible, but in no case lessthan 80° to the centre-line of the road. The angles ofcrossing for other roads (like seasonal roads, unpavedvillage roads, cart-tracks, etc) shall be as close to 90°as possible, but in no case less than 45°to the centre-line of the roads.

Major river crossings shail be established as close aspossible to the locations shown on the route map.Crossings shall be located in a comparatively straightreach of the river, where the banks are stable and thereis sufilcient area for construction. Angle .of crossingshall be as close to 90° as possible. For canals/drainage/ditchhalakream and other watercourses, the angle ofcrossing shall be as close to 90° as possible but in nocase less than 60° .to the centre-line of the canal/drainage ditch. As far as possible, crossings shall belocated where there is minimum evidence of slumpingor erosion of banks or bed.

Other utilities crossed shall be located at their centre-lines with stakes containing station numbers in thesurvey.

19

The requirements specified in IS 15663 (Part 2) shallalso apply.

7.2.2.5 Chainage and horizontal angles

Distance between intersection points staked along thepipeline route shall be measured and recorded. Inaddition, distance between level points shall also bemeasured and recorded. Chainrng will be continuousin the direction of survey. The true bearing of allstraights shall be observed and recorded. The natureof terrain like sandy, stony, vegetation, etc, and type ofground will also be recorded, along with the chainageof change points.

Horizontal angles shaLl be measured to indicate thechange in direction of alignment and specify thehorizontal bend at the turning points. ‘Rue bearing atthe beginning, end and every 15 to 20 km shall beobserved, to keep a check on errors in angularmeasurements.

7.2.2.6 Pipeline route profile

The continuous profile of the proposed pipeline routeshall be established from the reduced levels taken atthe starting point, at all Turning Points (TPs), at allIntermediate Points (IPs) staked on the ground, at allpoints on the pipeline route where there is a-change insIope and at sufilcient number of other points so as togive an accurate ground profile along the route.

For road and railway crossings, the reduced levels shallbe recorded at all points along the pipeline alignmentwherever there is a change in slope within the entirewidth of the right-of-use of the roadhailway.

For river/stream/nala/canal crossings, levels shall betaken at intervals of 5 m, up to a distance of 30 mbeyond the highest banks on both sides. Levels shallbe taken at closer intervals, ifthere is a change in slope.For major water crossing sites, cross-section as aboveshall be observed at both banks.

All levels shall be with respect to Mean Sea Level(MSL).

7.2.2.7 Surv~ maps and drawings

Survey maps and drawings to appropriate scales shallcontain all relevant data consistent with the surveynotes and observations. The drawings shall also containdetails of roads, streets, highways, structures, all typesof crossings, terrain, surface vegetation and all otherdetails that would be required for the purpose ofengineering design.

7.2.2.7.1 Survey drawings shall contain the followingdata as a minimum requirement:

a) Pipeline route map shall show all featuresincluding, but not limited to roads and

b)

c)

d)

IS 15663 (Part 1): 2006

railroads, canals, streams, lakes, rivers,villages, towns, and cities that are locatedwithin a distance of 5 km from the pipelinecentre-line on either side of it. For the entireregion, contours shall be plotted on the routemap at 20 m contour interval. For areas whichare undulating, such as hilly areas, ghatregions, ravines, and other areas feltnecessary, contours shall be plotted at 10 mcontour interval. Additional information likecultivated areas, barren land, areas prone toflooding, rocky areas and forests includingaccess paths/roads to right-of-use shall alsobe shown on the route maps;

Right-of-use planimetry drawings shall showall objects within 50 m on either side of thepipeline in plan;

In case of all rail, road, river, stream, canaland utility crossings, the cross-sectional detailand the angle of crossing shall be mentioned.In case of rail, road, river, stream and canalcrossings wider than 10 m, the distances atthe start and at the end of the crossing fromthe nearest Intermediate Point (1P) shall alsobe mentioned. For crossings less than 10 mwide, the distance of the centre-line of crossingfrom the nearest 1Pshall be given. For all ri,y$r,stream and nala crossings, the level of waterat the time of survey and the approximatesurface velocity of the flowing stream shallbe observed and recorded and reported in thesurvey drawings. Also, the general nature ofthe surface soil (soft/hard or normal soil orrock/boulders) at the bed and banks of theriver/stream/nala shall be observed andmentioned in the drawings; and

Ground profile and cross-section for slopedright-of-use.

7.2.3 Soil Investigation

Soil investigation shall be carried out in order to obtainthe visual engineering classification of soil along thepipeline route. Soil investigation would include boring,collection of disturbed samples from bore holes, visualengineering classification of soil along the pipelineroute and submission of detailed report which shallinclude soil profiles along the pipeline route in additionto visual classification of the soil. Visual classificationof soil shall be in accordance with IS 1498.

Boreholes for soil samples shall preferably be made atintervals of 500 m along the pipeline route, at allintermediate points where there is apparently a changein the type of soil and at any other.place as necessary.For canal, stream and river crossings, boreholes shallbe made one on either bank and one on the bed.

13

IS 15663 (Part 1): 2006

Disturbed representative samples shall be collectedfrom boreholes for visual classification of the sub soilat site.

Regions along the pipeline route where specialexcavation techniques like blasting, etc, is needed forexcavation of pipeline trenches shall be clearlyindicated in the soil investigation report.

7.2.4 Preparation of Right-of Way

Construction activities shall be carried out within thewidth of the right-of-use set aside for construction ofpipeline, unless other arrangements with the landowner/appropriate authorities are made. For trunkpipelines a minimum strip of 30 m right-of-use shallbe used for construction, For smaller diameter pipelinesof below 300 mm diameter, a minimum strip of 20 mright-of-use shall be used for construction.

Prior to clearing operations, the following shall beensured:

a)

b)

c)

d)

Benchmarks, intersection points and otherrequired survey monuments are installed;

Stake markers are placed in accordancewith 7.2.2 as compared with the drawings;

Two right-of-use markers are staked at leastat every 100 m; and

A reference line witkrespect to pipelinecerme-Iine at a convenient location is ‘set ou~ withmarkers on the reference line at a distance of amaximum 100 m for straight sections and amaximum 10 m for horizontal bends.

The right-of-us.e shall be graded and cleared of allobstacles as required for proper installation/laying ofthe pipeline and for providing access duringconstruction.

7.3 Welding

Unless stated otherwise in the standar~ all welding workincluding weld-inspections, equipment of welding, heattreatment and welding personnel shall meet therequirements of API 1104. Unless otherwise specifiedelsewhere in the standard the requirements in ASMEBoiler and Pressure Vessel Code, Section IIC Shallapplyfor filler materials and Section V shall apply for non-destructive examination of welds.

7.3.1 Welding Consumables, Equipments andAccessories

All consumables shall be suitable for the weldingprocess and shall have the physical and chemicalproperties as that of pipe parent metal. The availabilityof sufficient number of welding and cutting equipment,equipment for heat treatment and other auxiliaries.andaccessories required for welding must be ensured.

7.3.2 Welding Processes

The specific process or combination of processes tobe used shall be identified. The use of manual, semi-automatic or automatic welding process or anycombination of these shall be as agreed betvwen thecontracting parties. Any of the following processes orcombination of processes can be selected for mainlineand tie-ins:

a)

b)

c)

d)

e)

Automatic gas metal arc welding (GMAW)from both sides or welding tkom outside withcopper backing;

Semiautomatic GMAW with specialcontrolled pulse waveform, capable of makingroot runs;

Shielded metal arc welding (SMAW) processfor root and hot passes and semi-automaticGMAW/Flux core arc welding (FCAW) forfill and caps runs;

Shielded metal arc welding (SMAW) process;and

Double jointing of two pipe lengths usingsubmerged arc welding (SAW)/automaticwelding in specially laid pipe welding yard,where feasible, may also be used.

7.3.3 Inspection Before Welding andkiarkings,,

Wherever the original pipe length is cut into one ormore pieces, the cut pieces used in main line weldingshall have a minimum length of 1m. Pipe identificationdetailsmarked on the main pipe shall be transferred oneach of the cut pieces.

The pipes shall be visually inspected for defects beforetaking up welding operation on them. Dents in pipesup to a depth equivalent to 2 percent of nominal pipediameter shall be acceptable. However dents shall notbe permitted within a length of 200 mm from the pipeends. Dents due to stress concentration, up to 5 percentof the pipe wall thickness maybe permitted. An ovality “of 1.5 mm at the pipe ends shall be acceptable. Beveldarnage up to a depth of 1;00 mm may be acceptedprovided that such damage is removed by grinding. Forbevel damages between 1.00 mm and 3.00 mm, the pipeend shall be re-bevelled -as per the appFoved jointgeometxy. For bevel damages beyond 3.00 mm the pipeend shall be cut and re-bevelled.

The pipe bevels shall be cleaned and inspected beforewelding and the followingensured:

a) All bevel ends shall be -free from rust, oil,grease, paint, oxide, sand, dust and surfaceirregularities;

b) Prior to making fit-up, pipe ends shall becleaned at both inside and outside, using

14

power brush, to a minimum length of 25 mmfi-omthe edge so as to ensure that no surfacedamagehregularities, rust, oil, grease, sand,dust, paint, etc, exists on the surface;

c) If new bevels are made, the bevel surfacesshall be subjected to dye penetrantexamination to ensure no lamination existson new bevel surface; and

d) If original pipe end is cut for a length of20 mm or more, ultrasonic examination atpipe end shall be carried out on a minimumlength of 20 mm on the entire circumferenceto ensure that no lamination/voids exist in thescanned area.

7.3.4 Weld Alignment and Spacing

The following requirements on the alignment andspacing of welds shall also be ensured:

a)

b)

c)

d)

e)

Orientation of welded pipes shall be soselected as to ensure that at circumferentialwelds, the longitudinal welds are staggeredin the top 90° of the pipe section or 250 mm,whichever is less. The longitudinal seam shallalways be kept on the upper quadrant(between 315° and 450);

A maximum offset of 1.6 mm at joints shallbe permitted. Hot dressing shall not beallowed;

Root gap, subject to a maximum of 2 mm shallbe provided in accordance with the qualifiedwelding procedure;

Distance between skid on both sides of theweld joint shall be at a.minimum possible inorder to avoid sagging and mechanicalstresses at the weld. joint. The height of theskid shall provide sufficient and unobstructedaccess for carrying out welding operation; and

For pipe diameters of 250 mm and above, useof internal lineup clamps shall be mandatory.Internal lineup clamp shall be removed onlyon completion of root pass. External lineupclamp shall be provided on completion of aminimum of 60 percent of root pass, withproper supporting on both sides of weld joint.In tie-in welds, external lineup clamps maybe used.

While welding pipes of different wall thicknesses, aspecial transition piecehaving a minimum taper in wallthickness of 1;4 shall be used. The weld shall be subjectto both ultrasonic and radiographic examination.

7.3.5 Weld Procedure

7.3.5.1 Pre-heating where required shall be consistentwith the established welding ‘procedure using induction

IS 15663 (Part 1): 2006

heatinghhne torch coil. Pre-heating shall extend to alength -ofat least three times the thickness of the jointbut shall not be less than 50 mm on both sides of theweld.

7.3.5.2 The welding procedure shall be qualified inaccordance with the applicable specifications.Sequence of welding and number of welders shall beconsidered while qualifying the procedure.

7.3.5.3 The root pass shall be made with electrode/filler wires as specified in the approved weldingprocess. The down hill welding shall be normally usedfor main line welding root pass. The vertical up methodof welding shall be used for the root pass of tie-ins,special crossings, fittings and special parts, fillet weldsand repairs. Unless otherwise specified, the weldprojection inside the pipe shall not exceed 3 mm.Welding shall be continued uninterrupted during theroot pass.

7.3.5.4 The actual time lapse between passes shall bein accordance with the established welding procedure.The following time lapse shall however be ensured:

a) In root and hot pass: maximum of 4 rein;

b) In hot pass and first filler: maximum of 5 rein;and

c) In Subsequent passes up to 50 percent wallthickness: maximum of 5 min. ‘‘”

Under no circumstances shall the welding bediscontinued till 50 percent of wall thickness has beenwelded.

7.3.5.5 The completed weld shall be free tlom all visualdefects like surface under cuts, weld spatters, pinholes,surface porosities, arc strikes, etc. Welds shall have areinforcement 1.5 to 2.0 mm heigh, with goodworkmanship, smooth finish and without any surfaceirregularities. The completed weld joints, includlng25 mm of pipe length on both sides of the weld, shallbe properly cleaned using power brush.

7.3.5.6 The weld joint shall be numbered and markedalong with the welder identification, adjacent to theweld joint on the progressing direction of main line inaccordance with an approved numbering scheme.

7.3.5.7 Tie-in operations shall be carried out inaccordance with the requirements specified in 7.4.12.

7.3.6 Weld Examination

7.3.6.1 Non-destructive examination shall be c~iedout an all girth welds. This shall be carried outpreferably using on-line automatic ultrasonic testing(AUT) in case of all welds made by automatic GMAWwith narrow bevels. Welds with API bevels may beexamined either by radiography (X-Ray) or AUT. In

15

IS 15663 (Part 1) :2006

addition, radiographic examination shall also berequired for first 100 weld joints corresponding toautomatic GMAW welding procedure to establishaccuracy of AUT. Radiography (X-Ray) shall be

. carried out for repaired welds. Tie-in and other weldshaving API bevel may be examined by radiography(X-Ray) or AUT.

7.3.6.2 The first ten joints welded using GMAWwelding process shall be subjected to ultra-sonictesting. When pipe ends are cut for 20 mm or more inlength, a minimum of 20 mm length of pipe at the endsshall be subjected to ultrasonic testing to ensure thatno lamination exists. Weld repair areas shall alsobe subjected to ultrasonic testing in addition toradiography. If required, ultrasonic testing shall berequired to confirdclari~ the defects indicated inradiographic examination.

7.3.6.3 Weld cuts for defects of any reasons shall besubjected to destructive testing similar to thedestructive tests carried out for welding procedurequalification. If the results are not satisfactory, weldingoperations shall be suspended and shall not be re-started until the causes have been identified andappropriate measures adopted that would ensureacceptable results.

7.4 Installation of Pipelines

Pipe bevel protectors shall always be kept in positionduring all handling, transportation and stringingoperations and shall be removed only prior to fill-upfor welding. Visual inspection of the bare pipes andthe coating of the corrosion coated pipes, as the casemay be, must be performed and all damages shall berecorded. In the case of pipes coated for corrosion,holiday detection at a prescribed set voltage andrecording of such holidays may be carried beforetransportation to the site. Repair of all such holidaysfound up to the time of laying the pipeline, shall becarried out before their burial.

7.4.1 Handling and Hauling of Line Pipes

Loading, unloading, transportation and stockpiling ofthe coated pipes shall be done using suitable meansand in a manner so as to avoid damage to the pipe andcoating. Use of round sectional slings shall not bepermitted. Rolling, skidding or dragging shall also bestrictly -forbidden. Coated pipes at all times shall bestacked completely clear from the ground so that thebottom row of pipes remain free from any surfacewater. The pipes sha[l be stacked at a slope so that rainwater does not accumulate inside the pipe. The coatedpipes may be stacked by placing them on ridges ofsand, -free from stones and covered or on woodensupports provided with suitable cover. The supportsshall be spaced in such a manner as to avoid permanent

bending of the pipes, particularly in case of pipes withlow wall thickness.

While lifting pipes, adequate care shall be taken not tokink or overstress the pipes. Proper approved pile slingsshall be used. A strip of soft material shall be placed inbetween skid (of adequate width) and pipe to protectthe external coating of the pipe. Skids shall not beremoved under a string before lowering in. The weldedpipes shall be maintained on skids at a minimumdistance of 500 mm above the ground. Crotches shallbe installed at frequent intervals (at least at every10th support), with an increased number at bends andon undulating grounds

7.4.2 .Stringing of Pipe

Stringing of pipe shall only be carried out in day lightand after clearing and grading operation of the right-of-use has been completed. Pipes shall not be strungon the right-of-use in rocky areas where blasting maybe required, until all-blasting is complete and the areacleared of all debris. In case the line pipe supply is bydifferent manufacturers, stringing of all line pipesof one manufacturer shall be completed beforecommencing the -stringing of the line pipes of anothermanufacturer. The pipe lengths shall be properlyspaced in order to facilitate easy handling duringwelding operations. The distance between the trenchedge and the pipe string shall be such as to providesafe working space. Stringing shall be carried out insuch a manner to cause minimum interference withpublic roads, footpaths, tracks, etc. All relevantidentification marks available on pipes while stringingshall be recorded for traceability and materialreconciliation.

7.4.3 Materials Other Than Line Pipes

Materials other than line pipes shall be stored insheltered storage. Such materials shall not be strungon the right-of-use but shall be transported in coveredconveyances for use only at the time of installation. Itshall be ensured that all valves and wheneverapplicable, other materials are fitted with suitable endcovers of the approved type. Materials with workedsurfaces such as flanges, pipe-fittings, etc, shall bestacked and handled so as to avoid contact with theground or with substances that could damage them. Themanufacturer’s instructions regarding temperature andprocedure for storing shall strictly be complied withfor such materials whose properties/characteristics areliable to change due to unsuitable storage conditions.If required, adequate heat conditioning shall beprovided for such materials. When supplied incontainers and packages, they must not be thrown ordropped nor handled using hooks which could damagethe container or the materials, either during loading/

16

unloading or during successive handling, till their finaluse.

7.4.4 ldentl~cation

All pipes and bends of size greater than 50 mm nominalbore shall be identified with a serial number as soonas possible, and accordingly indelibly marked on thepipes, along with the measured length. Pipes to be bentshall be measured prior to bending. Before a pipelength, pipe end, etc, is cut, the painted serial numberand stamped-in pipe number shall be transferred toeither side of the joint which is to be made by cuttingand the changes shall be recorded, stating the newlength.

7.4.5 Trenching

Pipeline trench shall be excavated and maintained onthe staked centre-line of the pipeline, taking intoaccount the curves of the pipeline. Normally trenchingoperation shall be carried out ahead of bending andstringing operations, unless otherwise required due tofactors like terrain, climate, site conditions, etc.

7.4.5.1 Excavation

In cultivable land and other areas specificallydesignated, the top soil on the pipeline trench top widthshall be excavated and stored separately. This top soilshall be replaced in original position after backfillingand compacting the rest of the trench. Suitablecrossings shall be provided and maintained over theopen right-of-use, where necessary, to permit generalpublic, property owners or his tenants to cross or movestock or equipment from one side of the trench to theother. Care shall be exercised to see that fresh soilrecovered horn trenching operation and intended tobe used for backfilling over the laid pipe in the trench,is not mixed with loose debris or foreign material. Allsewers, drains, ditches and other natural waterwaysencountered in the execution of the works shaIi bemaintained open and fictional. The same would alsoapply to canals, irrigation canals, pipelines and buriedfacilities crossed by the trench for which temporarypipelines -shall be laid, if required, and appropriatetemporary installations provided.

7.4.5.2 Blasting

Blasting-operations where considered necessary shallbe carried out after obtaining required permission fromstatutory authorities and after ensuring all identifiedsafety precautions. Blasting operation and removal ofdebris shall be carried out prior to stringing of pipes.Blasting for trenching and the removal of scattered rockand debris caused by the blasting from the right-of-use andlor adjacent property shall be carried out in themanner described herein. Every possible precautionshall be taken to prevent injuries and damages to

IS 15663 (Part 1) :2006

persons and properties during blasting operations. All .necessary precautions shall be taken to prevent stonesfrom falling outside the right-of-use and in thecultivated areas and to avoid any damage to theinstallations and properties existing nearby. Blastingshall be carried out by qualified blasting personnel inaccordance with statutory requirements on same.

7.4.5.3 Normal cover and trench dimensions

The pipeline shall be buried-at a depth as to meet thecover requirements of 5.8.2. The trench shall beexcavated to a minimum width so as to provide, onboth sides of the installed pipeline, a clearance asindicated in the job standards/drawings and to a depthsufficient to provide the minimum cover as givenin 5.8.2 and any requirementof padding (see 7.4.5.5).

7.4.5.3.1 Additional soil cover shall be provided atlocations that are likely to have an increased risk ofimpact damage or third party interference. Wheneverit is permitted by any authorities to open cut a pavedroad crossing or where the line is routed within theroad pavement, the paving shall be removed inaccordance with the requirements of the authoritieshaving jurisdiction thereof. The open cut for the roadcrossing shall be carried out only when the section ofpipeline to be laid is complete. For rdl roads, paths,walkways, etc, that are open cut, temporary diversionsshall be properly constructed to allow the passage ofnormal traflic with the minimum inconvenience’’’kmdinterruptions. Additional depth shall also-be excavatedat points where the contour of the earth may requireextra space to fit the minimum radius of pipe bend asspecified or to eliminate unnecessary bending of thepipe, according to customary good pipeline practice,or where a deep trench is required at the approaches tocrossings of roadways, railroads, watercourses (rivers,streams, drainage, ditches, etc) and the like. Thepipeline may be laid with at least 300 mm”fieeclearancefrom the obstacle or as specified in the job drawings,or such minimum distances as may be required byauthorities having jurisdiction thereof.

7.4.5.4 Grades, bends andfinish of trench

The trench shall be cut to a grade that will provide afirm, uniform and continuo~s support to the pipe. It isrecommended to reduce the cold field bends to aminimum number to lay the pipeline conforming tothe general contour of the ground and to maintain anormal cover. Finishing of the bottom of the trenchshould be done mechanically or manually, asnecessary, to ti-eethe bottom of the trench from looserock and hard clods and to trim protruding roots fromthe bottom and side walls of the trench.

7.4.5.5 Padding

In all cases where rock or gravel or hard soil is

17

IS 15663 (Part 1): 2006

encountered in the bottom of the trench, a padding shalibe provided. The thickness of the compacted paddingshall not be less than 150 mm. In those areas that are tobe padded, the trench shail be at least 150 mm deeperthan otherwise required. The trench shall be evenlyand sufficiently padded to keep the pipe, when in place,at least 150 mm above bottom of excavated trench.The thickness of compacted padding on top of pipecorrosion coating shall be at least 1-50mm. Gradedsoil/sand and/or other materials not containing gravel,rock or lumps of hard soil shall be considered asapproved grading materials.

7.4.5.6 Protection of trench and other undergroundutilities

Trench shall be kept in good condition and protectedfrom caving in. Wherever required, shutteringhttressframing shall be provided in the trench (depending-upon depth and side wall slopes and soil conditions)to avoid caving in.

Complete detail of underground utilities shall beobtained. Plans and full details of all existing andplanned underground services from the relevantauthorities shall be obtained and these plans shall beclosely followed at all times during the performanceof work. In locations where the use of trenchingmachine/backhoe may result in damage to property andsubsurface structures, excavation shall be carried outmanually. Where the pipeline crosses otherunderground utilitieskuctures, the excavation shallbe carried out manually and in such a manner as tolocate such utilities/structures.

7.4.5.7 Provisions for negative buoyancy to the pipe

In the case of water being acountered at the bottomof the ditch while laying the pipeline, the ditch shallbe drained to enable visual inspection of the ditchbottom. The presence of water in the ditch afier suchinspection may be allowed provided that the water leveldoes not cause sliding of the ditch sides and/or floatingof the pipe when no concrete weighing is provided,before backfilling. Weighing of the pipelines in suchinstances shall be by any of the following methods:

a)

b)

c)

d)

e)

weighing by applying a continuous concretecoating around the pipe;

weighing by installing saddle weights;

installing metal anchors screwed into thesubsoil in pairs;

deeper burial of pipeline;.and

provision of select backfill material.

7.4.6 Bending

7,4.6.1 Changes of vertical and horizontal alignmentshall preferably be provided by making elastic bends.

(optionally,cold field bends may be provided for changeof direction and change of slope. A radius smaller thanpermitted in elastic bending shall however require acold field bend.

7.4.6.2 Over bends shall be made in such a mannerthat the centre of the bend clears the high points of’thetrench bottom. Sag bends shall fit in the bottom of thetrench and side bends shall confirm and leave specifiedclearance to the outside wall of the trench.

7.4.6.3 Cold$eld bena3

The radius of cold field bends shall be as specifiedin 6.3.

Bending machines shall be capable of making bendswithout wrinkles, buckles, stretching and withminimum damage to-the coating. A bending procedureshall be fixunedbefore start of work in accordance withthe recommendations of the manufacturer of the“bendingmachine. The procedure shall include amongstother steps the length, maximum degree per pull andmethod and accuracy of measurement during pullingof the bend.

Pipes with longitudinal welds shall be bent in such away that the weld lies in the plane passing through theneutral axis of the bend, which shall be installedpositioning the longitudinal weld in the upperquadrants. If horizontal deviations are to be achieved”by joining a number of adjacent bends, the bending ofthe pipe lengths shall be made by positioning thelongitudinal welds alternatively 70 mm above andbelow the plane passing through the neutral axis in .such a way that the bends are welded with thelongitudinal welds displaced by about 150 mm andsituated in the upper quadrants. In case of vertical bendsformed from a number of pipe lengths, the longitudinalwelds shall be positioned on the plane passing throughthe neutral axis of the bend alternatively to the rightand left.

The pads, dies and rolls of the bending equipment shallhave relatively soft surfaces to avoid damage to thepipe coating.

The ends of each bent length shall be straight and notinvolved anyway in the bending. In no event shall theend of the bend be closer than 1.5 m tlom the end of apipe or within one meter of a girth weld. The ovalityin each pipe due to bending shall be less than2.5 percent of the nominal diameter, at any point. Acheck shall be performed on all bends by passing agauge consisting of two discs with a diameter equal to95 percent of the nominal internal diameter of the pipeconnected rigidly together at a distance equal to300 mm.

The wall thickness of finished bends, taking into

18

account wall thinning at the outer radius, should notbe less that the design wall thickness.

NOTE -– An indication of wall thinning as a percentage, isgiven by the fotlowing empirical formula:

50Wall Thinning ‘—-

n+l

wherem = inner bend radius divided by pipe diameter.

Pipes with measured wall thickness greater than thenominal wall thickness (with positive tolerance) shallnormally be used for making cold field bends.

Cold bend pipes on site shall have thecorrosion coatingcarefully checked with the aid of a holiday detectorfor cracks in the coating down to the pipe wall. Anydefects or disbanding of the coating caused duringbending (including forced ridges in the coating) shallbe repaired.

7.4.6.4 Mitre and unsatisfactory bena%

No mitre bends shall be permitted in the constructionof the pipeline. Cutting of factory made bends and coldfield bends for any purpose shall not be permitted. Allbends showing buckling, wrinkles, cracks or othervisible defects or which are in any way in disagreement,in whole or in part, with this specification shall berejected.

7.4.7 Pipe Defects and Repairs

7.4.7.1 Dents

The depth of dent shall be measured as the gap betweenthe lowest point of the dent and the original contour ofthe pipe. The maximum permissible depth of dents inpipes up to and including 324 mm nominal outsidediameter shall be 5 mm. For pipes over 324 mmnominal outside diameter, the permissible depth of dentshall be 2 percent of the nominal pipe diameter.

Dents which contain scratch, gouge, bum or groove;and dents located at the longitudinal or circumferentialweld shall be removed by cutting out a cylindricalportion containing the damaged portion of pipe. If dueto cutting or repairs, the pipe identification number isremoved, it shall be transferred onto the cutirepairedpipe. No pipe without identification number shall betransported andlor welded into the pipeline. Repair ofdamaged pipe ends by hammering and/or heating isnot allowed. In case of minor dents located at least200 mm tlom the pipe end may be straightened withthe help of a jack provided the pipe metal is not split,severed or stretched.

7.4.7.2 Gouges, grooves and notches

Injurious gouge and grooves shall be removed bygrinding to a smooth contour provided that the wallthickness is not reduced to less than the minimum

IS 15663 (Part 1) :2006

specified. When the above conditions cannot be met,the damaged portion of the pipe shall be cut out andreplaced with a good piece of pipe.

Notches on pipe surface can be caused by mechanicaldamage in manufacture, transportation, handling orinstallation. These shall be treated in a manner similarto gouges and grooves.

7.4.7.3 Arc burns

Metallurgical notch caused .by arc burns shall beremoved by grinding, provided that the grinding doesnot reduce the wall thickness to less than the minimumspecified. Care shaIl be exercised to ensure that heatof grinding does not produce a metallurgical notch.Inother cases the defective portion of the pipe shall becut out and replaced with a good piece.

7.4.8 Night .Caps

At the end of each day’s work or when joining andwelding operations are interrupted, the open ends onthe welded strings of pipes shall be capped with asecurely closed approved metaI cap or plug. Thesecovers shall not be removed until the work is to beresumed. The caps/plugs used shall be of mechanicaltype and shall not be attached to pipe by welding or byany other means which may dent, scratch or scar thepipe.

7,4.9 Lowering,,, ,

7.4.9.1 Lowering in trench

Lowering shall commence after the removal of all offcuts, pipe supports, stones, roots, debris, stakes, rockprojections up to 150 mm below underside of pipe andany other rigid materials which could lead toperforation or tearing of the coating, from the trenchbottom. Sand padding and/or rock shield shall beprovided as required. Lowering operation shall follow,as soon as possibIe,the joint coating of the pipeline.

Before lowering in, a complete check by a fill circleholiday detector for pipe coating and for field jointcoating shall be carried out and all damages repaired.All points on the pipeline where the coating has beenin contact with either the skids or with the liftingequipment during the laying operation, shall becarefully inspected for damages, dents or other defectsand shall be completely repaired. Before the lastoperation, a check must be made of the coating at pointsof contact with the supports. Short completed sectionsof the pipeline-shall-be cleaned with compressed air inorder to remove dirt from the inside of pipe sections.

The pipeline shall be lifted and laid using, for allmovements necessary, suitable equipment of non-abrasive material having adequate width consideringthe fragility of the coating. Care shall be exercised

19

IS 15663 (Part 1) :2006

while removing the slings from around the coated pipeafter it has been lowered into the trench. No sling shallbe put around field joint coating.

Wherever the pipeline is laid under tension, as a resultof an assembly error (for example, incorrectpositioning of bends, either horizontal or vertical), thetrench shall be appropriately rectified.

7.4.10 Laying

Laying of the pipeline shall be carried out under safeconditions so as to avoid stresses and temporarydeformations of the equipments which may causedamage to the pipeline itself and to the coating. Thepipe shall be placed on the floor of the excavation,without jerking, falling, impact or other similarstresses. Care shall be taken that the deformationcaused during the raising of the pipe string from thesupports, does not exceed the values for minimumallowable radius of elastic curvature so as to keepthe stresses on the steel and on coating within thesafe limits. The portion of the pipeline between trenchand bank shall be supported by as many side-boomsor other equipment as required, for holding the Iinein gentle s-curve, maintaining the minimum elasticbend radius. Lowering in and back-filling shallpreferably be carried out at the highest ambienttemperature.

Where water is present, no laying shall be permitteduntil the ditch has been drained to the extent and forthe time necessary to make visual inspection possibleof the bed on which the pipe is to be laid (see 7.4.5.7).

Movement of the pipe in a trench shall be preventedby appropriate means. Sand/earth filled bags shall beplaced between parallel pipelines along the trench.

7.4.11 Backfilling

7.4.11.1 Backfilling shall not be carried out until thepipe and appurtenances have the proper fit, and thepipe follows the ditch profile at the required depth thatwill provide the required cover and has abed which isfree of extraneous material and which allows the pipeto rest smoothly and evenly.

7.4.11.2 Backfilling shall be carried out immediatelyafter the pipeline has been laid in the trench. Ifimmediate backfilling is not possible, a covering of atleast 200 mm of earth, free of rock and hard lumpsshall be placed over and around the pipe and coating.On no account shall the top soil from the right-of-usebe used for this purpose. In general, the trench shall bedry during backfilling. The backfill material shallcontain no extraneous material and/or hard lumps ofsoil, which could damage the pipe and/or coating orleave voids in the backfilled trench. The surplusmaterial shall be neatly crowned directly over the

trench and the adjacent excavated areas on both sidesof the trench. The crown shall be high enough toprevent the formation of a depression in the soil whenbackfill has settled to its permanent position. Surplusmaterial, including rock, left ffom this operation shallbe disposed of to-the satisfaction of landowner or theauthority concerned. Rock, gravel, lumps of hard soilor like materials shall not be backfilled directly on tothe pipes unless padding and/or rock shield has beenprovided.

7.4.11.3 Where rock, gravel, lumps of hard soil or likematerials are encountered at the time of trenchexcavation, sufficient earth, sand or select backfillmaterials shall be placed around and over the pipe toform a protective cushion extending at least to a heightof 150 mm above the top of the pipe. Loose rock maybe returned to the trench after the required selectedbackfill materials has been placed, provided the rockplaced in the ditch will not interfere with the subsequentuse of the land,

7.4.11.4 When the trench has been dug throughdriveways or roads, all backfills shall be executed withsand or an approved suitable material and shall bethoroughly compacted. Any public or private authorityhaving jurisdiction over a road, street or driveway mayrequire that the surface of the backfill be graded withcrushed rock or some other purchased material andthe road shall be repaved. Trenches excavated in dikes,wh”ichare the property of railways or which are partsof main roads, shall be graded and backfilled in theiroriginal profile and condition. The trench in irrigatedand paddy fields shall be backtiIled to within 300 mmof the top, then rammed and further backfilled untilthe trench is completely backfilled.

7.4.11.5 At the end of each days work, backfillingshall not be more that 500 m behind the head end oflowered in pipe, -which has been padded and approvedfor backfill. The backfill shall be maintained againstwashouts.

7.4.11.6 Breakers shall be installed in trenches in steepareas (slope of generally 10 percent and more) for thepurpose of preventing erosion of the backfill. Whenbackfilling the trenches in sloping terrains or steepareas, wherein the chances of washout of backfill exist,sheet piling or other effective water breakers acrossthe trench shall be provided, to divert the flow of wateraway from the trench into normal drainage followed,before laying of the pipeline.

7.4.11.7 The maximum allowable deviation from thecentre-line for land sections as staked out and afterbackfilling shall be limited to 200 mm for pipelineswith pipe up to and including 600 mm nominal boreand 300 mm for pipelines.of pipes larger than 600 mmnominal bore.

20

7.4.11.8 The backfill shall be stabilized with suitablematerials. Temporary markers shall be installed duringbackfilling to locate the pipeline axis. These markersshall be subsequently replaced with permanent pipelinemarkers.

7.4.12 Tie-in

Tie-in shall preferably be carried out at ambienttemperatures corresponding to the average operatingtemperature. The tie-in should be done in such a wayas to leave a minimum of strain in the pipe. If necessary,realigning of the pipe with respect to the trench shallbe carried out to eliminate any force or strain in thepipe.

7.4.12.1 Bell holes made to facilitate weldingoperations shall provide adequate clearance to enablethe welders to exercise normal welding ability and skill.All tie-in welds shall be radiographically examined. Ifa pup end cannot be avoided for tie-in, a minimumlength of 1 m shall be added and tMo or more suchpups shall not be welded together. Tie-in with two ormore pups may be used provided that each have aminimum Iength of 1 m and are separated by an entirelength of pipe. In no case more than three welds shallbe permitted on a 10 m length of pipeline. For tie-in of-adjacent sections of pipeline already pressure tested,the pup used for tie-in shall be of single length or off-cuts of pipe which have already been hydrostaticallytested.

7.4.13 Installation’ of Sectionalizing Valve and ValveStations

The valve shall be installed only after the successfulcompletion of hydrostatic test and dewatering. Valvesshall be installed on suitable concrete foundation.Valves with flow arrows shall be installed accordingto the normal flow in the pipeline. During welding,the valves shall be in fitly open position. In addition,all manufacturers instructions shall be followed in theinstallation of the valves. Care shall be taken to avoidentry of sand particles to valve body and seals duringtransportation, storage, assembly and installation.Valves and piping installed below ground shall begiven any approved anti-corrosion coatinglpainting.The anti-corrosion coating below ground shall extendup to 300 mm above ground at the lowest paint.

Sectionalizing valves shall be installed on sections ofthe pipeline in the horizontal position only. Installation-shallbe done in such a manner that there is no strain inthe welded joint while the pipeline .at upstream anddownstream side are straight. All valves shall behandled using equipment and methods to avoid impact,shaking and other stresses. All sectionalizing valve andany other inline assemblies shall be prefabricated andtested hydrostatically ex-situ. The tie-in joints shall be

IS 15663 (Part 1): 2006

radiographically examined over the entire length andultrasonically examined prior to backfilling.

7.4.14 Installation of Insulating Joints

Insulating joint and welded joint shall be protected byan external coating.

The insulating joint shall be inserted on straightsections and laid on a tine sand-bed.

During the execution of the in-line connection welding,the propagation of heat shall be avoided. To achievethis, the joint shall be kept cold by means of continuouswetting using appropriate means.

Insulating joints shall be electrically tested beforewelding onto the pipeline. The insulation resistanceacross the joint shall be about one 1 Mf2. The testsshall be repeated after installation and welding of thejoint into the pipeline to veri~ that the assembly isundamaged.

7.4.15 Laying in Crossings

Crossings shall be laid in accordance with theapplicable requirements in IS 15663 (Part 2).

7.5 Hydrostatic Testing

7.5.1 General

Hydrostatic pressure tesing shall be carried out inaccordance with the requirements specified in 5.9.

The number of test sections should be minimized takinginto account safety of personnel and public; protectionof environment and other facilities; sequence ofconstruction; accessibility; and the availability anddisposal of test water. Equipment that should not besubjected to the test pressure shall be isolated from thepipeline. Valves should not be used as end closuresduring pressure testing, unless they are designed towithstand the differential pressure across the valveduring testing. All end closures shall have sufficientstrength to withstand the test pressure. Individualcomponents and fabricated items may be pretested inaccordance with the provisions of thk standard.

Work on or near a pipeline under test shall not be-permitted for the period from the commencement oftesting to the end of the test, except where necessaryfor the testing. Warning signs shall be placed and thepipeline route.put under surveillance to prevent accessto the pipeline during testing. In the case of pneumatictesting, the hazards from testing shall be taken intoaccount when designing the safety requirement. Thesafety of the public, construction personnel, adjacentfacilities and protection of the environment shall beensured when depressurizing the pipe test medium.

A detailed pressure testing procedure shall be prepared

21

IS 15663 (Part 1): 2006

which shall include hydrostatic pressure test diagramsfor each test section; filling and flushing procedures;equipments and instruments required, their locationsand set up; type and sequence of pigs, pig trackingsystems and pig inspection; estimated quantity of waterrequired for testing; detection of leaks; dewatering andtest data.

Hydrostatic test shall be commenced only after thecompletion of all mechanical and civil works (all weldshave been accepted and pipeline laid and backfilled inaccordance with the requirements of the standard).

7.5.2 Hydrostatic Test Section

Final hydrostatic pressure testing shall include allsections which have been previously tested like thoseat rail/road crossings, major water crossing, etc.

Based on actual gradient of pipeline section, it shallbe ensured that test pressure at any location does notexceed or fall below the maximum and minimumpermissible limits specified in 5.9.2. The maximumlength of any test section shall not exceed 50 kms.

7.5.3 Test Pressure

The test pressure and the duration of testing shall be inaccordance with that specified in 5.9.2. The duration oftesting shall be considered from the time of stabilizationof the test pressure. Pressure and temperature at startand end of the test shall be recorded.

7.5.4 Testing Equipments and Instruments

The following equipments/instruments shall beavailable for conducting the testing.

a)

b)

c)

d)

e)

o

g)

h)

j)

k)

m)

Cleaning pigs;Four-cup batching pigs;

Gauging pigs;

Caliper pigs of appropriate accuracy to detectand locate deformities smaller than thosepermitted;

Fill pumps of appropriate capacity;

Portable tanks of sufficient size to ensureavailability of continuous water duringpressurization;

130urdon pressure gauges of accuracy of0.01 kg/cm2 and capable of measuring inincrements of 0.05 kg/cm2;Two, 48 h recording pressure gauges withcharts and ink gauges;

Two temperature recorders for recording thetemperature of filled water;Thermocouples for measuring pipe walltemperature;‘rwo laboratory thermometers to be used inthermo-wells;

n)

P)

q)

r)

Means to measurenecessary to drop0.5 kg/cm2;

the volume of waterthe line pressure by

Suitable communication equipment for acontinuous communication between thebeginning and the end of the test section forthe inspection team along the line;

Temporary scrapper traps for launching andreceiving of each pig independently, -and

Injection facilities to inject additives(inhibitors) into the test medium.

7.5.5 Test Procedure

The test medium shall be as specified in 5.9.1. Freshwater, well -filtered, uncontaminated and free fromsand/silt shall be used. Approved corrosion inhibitors,oxygen, scavengers, etc, shall be added to the water.Installation of temporary piping may, if required, bemade to connect water source to the pumps andmanifolds/tanks.

Pipeline shall be cleaned with air driven pigs forremoving all mill scale, rust and sand from the insideof pipe sections before filling with test medium. Theresults for each pig run -shall be analyzed for suchpurpose..No extraneous material shall be found in frontof the last four-cup pig in cleaning. Results of thegauging pig run shall be analyzed for roundness along.the pipeline.

Flushing of the pipeline section shall be done withuninhibited water equivalent of 10 percent of totalvolume of the section. Air vents shall be kept closed atthe start of filling for the pressure build up.

Thermal stabilization after the inhibited water hasbeen flushed for a minimum of 2 h, shall beconsidered to have been ensured when a differenceof not more than 10°C, between the average valuesof the two temperature readings from thermocouplesattached to external surface of pipe wall; and thepressure of at least 1 kg/cm2 on the highest sectionhas been attained.

.Pressurization shall be done at a moderate andconstant rate not exceeding 2 kg/cm2/min. Volume ofwater shall be recorded intermittently duringpressurization. The pressurization cycle shall consistof the following steps:

a)

b)

c)

Pressurization to 50 percent of test pressure,holding pressure for 1 h and then droppingthe pressure to static head,

Pressurization to 75 percent of test pressure,holding pressure for 1 h and then droppingthe’pressure to static head, and

Pressurization to test pressure.

22

Air volume calculation in each pressurization cycleshall be made. If a decrease in pressure is observedtwice during the hold pressure period, the line shallnot be ccmsidered suitable for testing. Presence of airin the piping shall be checked by menns of air-volumecalculation carried out as described below:

a)

b)

c)

d)

Two separate consecutive pressure loweringof 0.5 kg/cm2 shall be carried out,

The volume of drained water correspondingto the second pressure lowering ( VJ shall bemeasured,

The theoretical volume (VP) derived fromcalculations shall be compared with ~, and

The ratio Vi/VBshall be equal to 1.06 +6 percent.

If the result meets the requirement, pressurization shallbe continued or otherwise, additional pig passage shallbe performed to remove the air pockets till the aboverequirement is fulfilled.

Test pressure shall be heldfor a minimum of 24 h atlerstabilization. Atler temperature and pressure have beenstabilized, the injection pumps shall be disconnectedand all connections at the test heads shall be checkedfor leakage. During the testing period, the pressure shallbe measured every hour and the ambient and pipe walltemperature measured every 2 h. Bleed off water shallbe accurately measured and recorded.

7.5.6 Acceptance Criteria

The test pressure shall remain constant throughoutthe test duration except for change due to temperatureeffects as evaluated. The pressure change due toalteration in temperature shall be algebraically addedto the pressure read on the pressure gauges. This valueshall be compared with the initial value and test shallbe considered as acceptable if the difference is lessthan or equal to 0.3 kg/cm2. In case of doubt, the testpressure shall be maintained for a further periodof24 h.

In the event of failure of the test section, the locationof leakage or failure should be ascertained. All leaksand failures within the pipe wall or longitudinal-seamshall be repaired by replacement of entire joint or jointsin which the leakage/failure occured. The method ofrepair shall be as approved by the owner. All defectivepipes shall be identified.

7.5.7 Termination of Testing

Test shall be terminated with written approval of the

IS 15663 (Part-1): 2006

inspection authority. Depressurization at a moderateand constant rate shall lx ensured. Dewatering of thetested line shall be carried out in the manner describedin 7.5.10.

7.5.8 Reporting

Proper record of the test should be maintained.

7.5.9 Precautions During the Test

Provision shall be made for the installation ofprecautionary warning signs and no-admittance signto unauthorized persons from the roads to the right-of-use. Such areas shall be properly fenced to preventaccess of unauthorized personnel. No unauthorizedpersonnel shall be closer than 40 m to the pipeline orequipment under test. Provisional scra~er ‘tram shallbe installed in compliance with methods-and at ~uitablelocations so that their rupture does not cause any injury/damage to personnel and property. Test section shallbe placed in such locations as to prevent it from beingaffected by a catastrophic failure in the test head. Afterdewatering the line, the sectionalizing valves and othervalve assemblies shall be installed. All thermo-couplesinstalled, shall be removed and damaged coating shallbe appropriately repaired.

7.5.10 Dewatering

Dewatering of a pipeline section shall be do,nesubsequent to the hydrostatic test of the respectivepipeline section using appropriately designed pigs. Thedisposal of the water shall be performed in accordancewith applicable statutory requirements.

The dewatering operation for the pipeline shall consistof a number of dewaterrng pig runs and dry air shall beused as propellant for pig trains. Pigs shall be suitablefor traversing the entire length of the pipeline/pipesegment. All the pigs shall be designed to preventdamage to the internal coating (if any) of the pipeline.The speed and the back pressure of the pigs shall be somaintained that continuous operation can be performedwithout the pig getting stuck.

Flushing of above ground piping at dispatch and receiptstations, sectionalizing valve stations, tap-off pointsand intermediate pigging stations shall be done withwater to remove debris from piping and then with dryair to remove the residual amount of water from theabove ground piping.

Before proceeding to next stage of operations, it shallbe ensured that the bulk water has been removed fromthe pipeline system.

,p

23

IS 15663 (Part 1) :2006

ANNEX A

(Clause 1)

— —

i

——— — —

—.—— —

——— ——

——— — —

— —–OFFSHORE

———— —

— ——— —

————

————

(ONSHORE

— —— —

. ———

——— ——

— ——— —

—— —

*

YMRS ‘---”:::~

CUSTODYTRANSFER

,1,ICs 1L--J Sv 1P P LIR

.- L-. 1

tGGS:1

L---J

1~-------- _

+* ,, l-.+----.,:,l

;;;{.~~$: ..’.’.Yy.*~:

GAS STORAGE FIELD MRSCUST;D~TRANSFER

+)——~--.-7

— — i RGP ~----1 I-----1

—— _ PIJR

—

(————————————

SV - Sectionalizing Valve 1P- Intermediate Pig Receiving Station

CS - Compressor Station LT - LNG Terminal

RGP - Re-gasifying Plant P UR - Pig Launcher I Receiver

* - Weli Without Separator GGS - Gas Gathering Station

~ - Weli With Separator oSP - Separation and/or Prwessing Plant

MRS - Metering Station

NOTE — Facilities and piping indicated by solid iines are within the scope of the standard.

FIG. 1 FACILITIESAND PIPELINESYSTEM COVEREDUNDER THESTANDARD

24

—. .— .——.—.— .——-

1S 15663 (part 1): 2006

ANNEX B

(Clause 4)

LIST OF APPLICABLE STATUTORY AND REGULATORY REQUIREMENTS

a) Environmental Protection Act, 1986 e) Factories Act, 1948

b) Environmental Protection Rules, 1986 ~ Air (Prevention and Contro/) Act, 1981

c) Coastal Area Classl@ation and Development g) Water (Prevention and Contro~ Act, 1974

Regulation h) Forest (Conservation) Act, 1980

d) Manufacture Storage and Importation of j) Petroleum and Minerals P@eIine Act, 1962

Hazardous Chemicals Rules, 1989 k) Indian Electricity Rules, 1956.

ANNEX C

(Clause 5.2.4)

DETERMINATION OF LOCATION CLASS

C-1 Population density index along the pipeline routeshall be determined as follows:

As zone, 400 m wide, shall be considered along thepipeline route with the pipeline in the centre-line ofthis zone. Then the entire route of the pipeline shall bedivided into lengths of 1 600.m such that the individuallengths will include the maximum number of dwellingsintended for human occupancy. The number of suchdwellings which are intended of human occupancywithin each 1600 m zone shall be counted and reportedalong with other survey data.

C-2 Areas shall be classified based on guidelines asgiven below:

a) Class 1 Location — A class 1 location is any1600 m section that has 10 or fewer dwellingsintended for human occupancy;

b) Class 2 Location — A class 2 location is any1 600 m section that has more than 10 butless than 46 dwellings intended for humanoccupancy;

c) Class 3 Location — A class 3 location is any1600 m section that has 46 or more dwellingsintended for hum-an occupancy except whena Class 4 Location prevails; and

d) Class 4 Location — A class 4 locationinclude areas where multi-storey buildingsare prevalent, and where traffic is heavy ordense and where there may be numerousother utilities underground. Multi-storeymeans four or more floors above ground,including the ground floor and irrespectiveof depth of basement or number of floors ofbasement.

C-3 In addition to the criteria contained in C-2 (a) to(d), while classifying areas, additional considerationmust be given to possibilities of increase inconcentration of population along the pipeline routesuch as may be caused by the presence of schools,hospitals, recreational areas of an organized character,places of assembly, places of worship, etc. If one ormore of these facilities are present, the area shall beclassified as a Class 3 Location.

C-4 Notwithstanding the above, while determiningclass location of an area due consideration shall begiven to the possibility of fiture development of thearea during the design life of the pipeline. If it appearslikely that fhture development may cause a-change inthe location class, this shall be taken into considerationwhile determining its class location.

25

IS 15663 (part 1): 2006

ANNEX D

(Clause 7.2.2.2)

. PIPELINE ROUTE SURVEY DATA SHEET

Pipeline size mm

Gradient (ROU) Along pipeline alignment, MaxAcross pipeline alignment, A&x

Bend radius

Minimum distance between TPs

Maximum deflection angle at TP

Permissible variation in pipeline length

ROU width to be acquired

Pipeline location in the ROU

Minimum distances from existing:

habitable dwellings

buildings/structures/monuments

property comers/monuments

Co-ordinates of starting point To be established on the alignment sheet prior toconstruction

NOTE — NumberofTPsorbendsinthepipeline,whether horizontal or vertical shall be kept to a minimum.

26

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Amendments Issued Since Publication

Amend No. Date of Issue Text Affected

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