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 8062-2 (2006): Code of Practice for Cathodic Protectionof Steel Structures, Part II: Underground Pipelines [MTD24: Corrosion Protection]

IS 8062 : 2006

~ tffi, ffi7r 3tR ~ cf>~ cf> ~~~/~ etr cfi~ wan -"f@r~

( 4$(17 TR7efUT )

Indian Standard

CATHODIC PROTECTION OF BURIED PIPELINE/STRUCTURE FOR TRANSPORTATION OF NATURAL

GAS, OIL AND LIQUIDS - CODE OF PRACTICE

( First Revision)

ICS 25.220.40; 75.200

c BIS 2006

BUREAU OF INDIAN STANDARDSMANAK BHAVAN, 9 BAHADUR SHAH ZAFAR MARG

NEW DELHI I 10002

April 2006 Price Group 9

Corrosion Protection and Finishes Sectional Committee, MTD 24

FOREWORD

This Indian Standard (First Revision) was adopted by the Bureau ofIndian Standards, after the draft finalized bythe Corrosion Protection and Finishes Sectional Committee had been approved by the Metallurgical EngineeringDivision Council.

This standard was first published in 1976. This standard has been prepared to serve as a guide for establishingminimum requirements for the control of external corrosion and underground pipeline/structure.

In this revision , following modifications have been made:

a) Requirement of the following Indian Standards have been merged :

I) IS 8062 (Part I) : 1976 Code of practice for cathodic protection of steel structures: Part I Generalprinciples

2) .IS 8062 (Part 2): 1976 Code of practice for cathodic protection of steel structures: Part 2Underground pipeline

b) Scope of the standard has been modified by including cathodic protection for pipeline/structure fortransportation of natural gas, oil and liquids keeping in view the present practices being followed in thecountry in laying of buried pipeline/structure;

c) New definitions have been included in the terminology clause; and

d) Cathodic protection design surveys and surveys during operation and maintenance have been included.

In the formulation of this standard , assistance has been derived from the following:

ISO 15589 - Part I : 2003 Petroleumand natural gas industries - Cathodic protection of pipeline/structuretransportation systems - Part I : On-land pipeline/structure, issued by theInternational Organization for Standardization (ISO)

ASTM G 97 : 1997 Standard test method for laboratory evaluation ofmagnesium sacrificial anodetest specimens for underground applications, issued by the American Societyfor Testing and Materials

NACE RP 0169 : 2002 Control of external corrosion on underground or submerged metallic pipingsystems, issued by the National Association ofCorrosion Engineers (NACE),USA

The composition of the Committee responsible for the formulation of this standard is given in Annex A.

For the purpose of deciding whether particular requirement of this standard is complied with, the fmal value,observed or calculated, expressing the result of a test or analysis, shall be rounded off in accordancewith IS 2 : 1960 ' Rules for rounding off numerical values (revised)'. The number of significant places retainedin the rounded off value should be the same as that of the specified valve in this standard.

Corrosion Protection and Finishes Sectional Committee, MTD 24

FOREWORD

This Indian Standard (First Revision) was adopted by the BureauofIndian Standards, after the draft finalized bythe Corrosion Protection and Finishes Sectional Committee had been approved by the Metallurgical EngineeringDivision Council.

This standard was first published in 1976. This standard has been prepared to serve as a guide for establishingminimum requirements for the control of external corrosion and underground pipeline/structure.

In this revision , following modifications have been made:

a) Requirement of the following Indian Standards have been merged:

I) IS 8062 (Part I) : 1976 Code of practice for cathodic protection of steel structures: Part 1 Generalprinciples

2) IS 8062 (Part 2): 1976 Code of practice for cathodic protection of steel structures: Part 2Underground pipeline

b) Scope of the standard has been modified by including cathodic protection for pipeline/structure fortransportation of natural gas, oil and liquids keeping in view the present practices being followed in thecountry in laying of buried pipeline/structure;

c) New definitions have been included in the terminology clause; and

d) Cathodic protection design surveys and surveys during operation and maintenance have been included.

In the formulation of this standard, assistance has been derived from the following:

ISO 15589 - Part 1 : 2003 Petroleum and natural gas industries -Cathodic protection ofpipeline/structuretransportation systems - Part I : On-land pipeline/structure, issued by theInternational Organization for Standardization (ISO)

ASTM G 97 : 1997 Standard test method for laboratory evaluation ofmagnesium sacrificial anodetest specimens for underground applications, issued by the American Societyfor Testing and Materials

NACE RP 0169: 2002 Control of external corrosion on underground or submerged metallic pipingsystems , issued by the National Association ofCorrosion Engineers (NACE),USA

The composition of the Committee responsible for the formulation of this standard is given in Annex A.

For the purpose of deciding whether particular requirement of this standard is complied with , the final value,observed or calculated, expressing the result of a test or analysis, shall be rounded off in accordancewith IS 2 : 1960 ' Rules for rounding off numerical values (revised) '. The number of significant places retainedin the rounded off value should be the same as that of the specified valve in this standard.

'"

AMENDMENT NO. 1 AUGUST 2006TO

IS 8062: 2006 CATHODIC PROTECTION OFBURIED PIPELINE/STRUCTURE FOR

TRANSPORTATION OF NATURAL GAS, OIL ANDLIQUIDS - CODE OF PRACTICE

( Tint Revision)

General - Substitute 'IS 8062 (Part 2) : 2006' for 'IS 8062 : 2006'wherever it appears in the standard

( First cover and page 1, Title ) - Substitute the following for theexisting:

'CODE OF PRACTICE FOR CAmODIC PROTECTIONOF STEEL STRUCTURE

PART 2 BURRIED PlPEUNElSTRUCTURES FORTRANSPORTATION OF NATURAL GAS, OIL AND LIQUIDS

( Flnt RevisioII)'

[ Second cover page, Foreword, para 3(a) ] - Substitute the followingfor the existing matter:

"a) Some of the requirements of 'IS ao62 (Part 1): 1976 Code ofpracticefor cathodic protection of steel structure : Part 1 General principles'have been incorporatedin tbis revision". .

(Sea:Jntl cover page, Foreword, ptI1YJ 3) - Add the following new pml aDa''(d)':

'This standaIdhas been issued in four parts. Theother parts are:

IS 8062 (Part 1) : 1976 Code of pl3dice .for cathodic protection of steelsttucturcs : Part 1 General principles ,IS 8062 (Part 3) : 1977 Code of practice for cathodic protection of steelstructures: Part3 Ship's hull

IS 8062 (Part 4) : 1979 Code of pr3ctice for cathodic proteetionof steelstructures : Part 4 Galvanic protection ofdockgates, caissons, piers and jetties. '

(M1D24)

Reprosraphy Unit. BIS, New Delhi, Iftdia

IS 8062 : 2006

Indian Standard

CATHODIC PROTECTION OF BURIED PIPELINE/STRUCTURE FOR TRANSPORTATION OF NATURAL

GAS, OIL AND LIQUIDS - CODE OF PRACTICE

( First Revision)

I SCOPE 3 TERMINOLOGY

2 REFERENCES

The following standards contain provisions whichthrough reference in this text, constitute provision ofthis standard. At the time of publication, 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 :

This standard deals with the general principles andrequirements of cathodic protection system forprevention against corrosion of external undergroundburied surface of metallic high pressure hydrocarbonproduct pipeline/structure.

This standard is intended to serve as a guide forestablishing minimum requirements for control ofexternal corrosion on pipeline/structure system.Corros ion control by a coat ing supplemented withcathodic protection should be provided in the designand maintained during service life of pipeline/structuresystem. Consideration should be given to theconstruction of pipel ine/structure in a manner thatfacilitates the use of in-line inspection tools.

Standard

ASTMG97 :1997

IS \0221 : 1982

IS 15569

(Part I) : 2006

(Part 2) : 2006

Title

Standard test method for laboratoryevaluat ion of magnesium sacrificialanode testspecimensforundergroundapplicationsCode of practice for coating andwrapping of underground mild steelpipeline/structurePetroleum and natural gas industries_ External coatings for buried orsubmerged pipelines used in pipelinetransportation of gas and liquidhydrocarbons :Polyolefin coatings (3-layer pe and3-layer pp)Fusion bonded epoxy coatings

For the purpose of this Code the definitions givenbelow shall apply.

3.1 Anode - The electrode of an electrochemicalcorrosioncell at which oxidation occurs. Electrons flowaway from the anode in the external circuit, which isnormally metallic. Corrosion usually occurs and metalions enter the electrolyte at the anode.

3.2 Anodic Area - That part of metallic surfacethat acts as the anode ofan electrochemical corrosioncell.

3.3 Anodic Polarization - The change of theelectrode potential in the noble (positive) directionresultingfromthe flow ofcurrent between the electrodeand electrolyte.

3.4 Backfill- The material which fills up the spacebetween a buried anode and the surrounding soil. Itshould have low resistivity, moisture retaining capacityand be capable of increasing the effective area ofcontact between the anode and the environment.

3.5 Bond - A metal piece having very little electricalresistance for connecting two points on the same ordifferent pipeline/structure.

3.6 Cable - One conductor or multiple conductorsinsulated from one another.

3.7 Cathode - The electrode of an electrochemicalcorrosion cell at which reduction occurs .

3.8 Cathodic Area - Area on which the cathodic(protection) current is picked up from an electrolyte.

3.9 Cathodic Disbondment - The destruction ofadhesion between a coating and the coated surfacecaused by products of a cathodic reaction.

3.10 Cathodic Polarization - The change ofelectrode potential in the electronegative directionresulting from the flow of current between theelectrolyte and electrode.

3.11 Cathodic Protection - A method ofprotectinga metallic pipeline/structure from corrosion by making

IS 8062 : 2006

it a cathode so that direct current flows on to thepipeline /structure from the surrounding electrolyticenvironment.

3.12 Cell - An electrolytic system consisting ofanode and cathode in electric contact with anintervening electrolyte .

3.13 Closed Hole Deep Ground Bed - Aninstallation in which the anodes are surrounded bybackfill.

3.14 Coating - Corrosion protective coating consistof various components/layers of a dielectric materialand is applied to a pipeline/structure to isolate it fromits immediate environment and to provide uniformlyhigh electrical resistance to flow of current betweenpipeline/structure and surrounding electrolyte.

3.15 Coating Disbondment - The loss of adhesionbetween a coating and the pipe surface .

3.16 Coating System - A coating consists ofvariouscomponents which provide effective electricalinsulation of the coated pipeline/structure from itsimmediate environment.

3.17 Conductor - A material suitable for carryingan electric current. It may be bare or insulated.

3.18 Continuity Bond - An intentional metallicconnection that provides electrical continuity.

3.19 Corrosion - The degradation of a material ,usually a metal or its properties , that results from anelectrochemical reaction with its environment.

3.20 Corrosion Potential- The mixed potential ofa freely corroding pipe/pipeline/structure surface withreference to an electrode in contact with the electrolytesurrounding the pipe/pipeline /structure.

3.21 Corrosion Products - Chemical compoundproduced by the reaction of a corroding metal with itsenvironment.

3.22 Corrosion Rate - The rate at which corrosionproceeds . (It is usuaIly expressed as either weight lossor penetration per unit time).

3.23 Coupling - The association of two or morecircuits or systems in such a way that electric energymay be transferred from one to another.

3.24 Coupon - Representative metal sample ofknown surface area used to quantify the effect ofcorrosion or the effectiveness of cathodic protection.

3.25 Criterion - Standard for assessment of theeffectiveness of a cathodic protection system.

3.26 Crossing Point - A point where two or moreburied or immersed pipeline/structure cross in aplan.

2

3.27 Current Density - The currentper unit area ofan electrode surface.

3.28 Direct Current (d. c.) Decoupling Device - Adevice used in electric circuits which allows the flowof a.c. in both directions and stops or substantiallyreduces the flow of direct current. The conduction ofcurrent takes place when predetermined thresholdvoltage levels are exceeded.

3.29 Deep Ground Bed - One or more anodesinstaIled a minimum of 15 m below earth 's surfacefor supplying cathodic protection current to anunderground/submerged pipeline/structure throughsoil/water.

3.30 Differential Aeration - Unequal access ofoxygen/air to various parts of a pipeline/structureresulting in local cell action and a consequent corrosionof the less aerated parts.

3.31 Diode - A bipolar semi-conducting devicehaving a low resistance in one direction and a highresistance in the other .

3.32 Drainage - Draining of electric Current from acathodically protected/affected pipeline/structure backto its source through an external conductor.

3.33 Drainage Bond - A bond to effect drainage ofcurrent.

3.34 Drainage Test - A test in which direct currentis applied usually with temporary anodes and powersources to assess the magnitude of current needed toachieve permanent protection against electrochemicalcorrosion

3.35 Driving Voltage - Driving voltage is the opencircuit potential difference between a pipeline/structure to be protected (a cathode) and the systemof anodes which protects it. This voltage does notinclude the voltage drop in the soil or in theconnecting load and is the total voltage available forestablishing a protective circuit. The driving voltagein galvanic cells is fixed while that in an impressedcurrent system is variable.

3.36 Earth

a) The conducting mass of earth or of anyconductor in direct connection therewith;

b) A connection, whether intentional orunintentional , between a conductor and theearth; and

c) To connect any conductor with the generalmass of earth.

3.37 Electrical Isolation - The condition of beingelectrically separated from other metallic pipeline/structure or the environment.

3.38 Electrical Survey - Any technique thatinvolves coordinated electrical measurements taken toprovide a basis for deduction concerning a particularelectrochemical condition relating to corrosion orcorrosion control.

3.39 Electrode - A conductor of the metallic class(including carbon) which carries current into or out ofan electrolyte.

3.40 Electrolyte - A chemical substance contain ingions that migrate in an electric field.

3.41 Foreign Pipeline/Structure - Any pipeline/structure that is not intended to be a part of the systemof interest.

3.42 Galvanic Anode - The electrode in a galvaniccouple formed by two dissimilar metals (as applied tocathodic protection) in which the galvanic current isflowing from this electrode into the electrolyte. Thegalvanic anodes corrode and are designated assacrificial anodes.

3.43 Galvanic Anode Cathodic Protection - Asystem in which current for cathodic protection of apipeline/structure is supplied by galvanic anodes. Asgalvanic anodes get consumed in the system is alsodesignated as Sacrificial Anode Cathodic ProtectionSystem.

3.44 Galvanic Cell - A cell consisting of twodissimilar metals in contact with each other in acommon electrolyte.

3.45 Galvanic Current - A current passing into orout of a pipeline/structure due to a galvanic couplebeing established in which the pipeline/structure formsone of the electrodes. By using less noble metalartificial galvanic couples are formed in such a way,that the galvanic current protects a desired pipeline/structure.

3.46 Galvanic Series - A list of metals and alloysarranged according to their corrosion potentials in agiven environment.

3.47 Ground Bed - A system ofburied or submergedgalvanic or impressed current anodes for supplyingcathodic protection current to ' a pipeline/structurethrough electrolyte.

3.48 Grounding Cell - A d.c. decoupling devicecontaining two or more electrodes, commonly madeof zinc, installed at a fixed spacing and resistivelycoupled through a prepared backfill mixture.

3.49 Holiday - A defect, including pinholes in anotherwise uniform protective coating that exposes themetal to the surrounding earth.

3.50 Impressed Current - A direct current impressed

3

IS 8062 : 2006

on a pipeline /structure from an external power sourcefor providing cathodic protection 10 it.

3.51 Impressed Current Anode - An anode thatprovides current for cathodic protection by means ofimpressed current.

3.52 Impressed Current Cathodic Protection - Asystem in which current for cathodic protection isprovided by an external source of d.c. power.

3.53 Impressed Current Station - A stationcontaining d.c. power equipment, anode ground bedand other items to provide cathodic protection bymeans of impressed current.

3.54 In-Line Inspection - The inspection of a steelpipeline/structure using an electronic instrument ortool that travels along the interior of the pipeline/structure.

3.55 Instant orr Potential - Pipeline /structure toelectrolyte potential measured immediately afterinterruption of all sources of applied cathodicprotection current.

3.56 Instant on Potential - Pipeline/structure toelectrolyte potential measured immediately afterswitching on all sources ofapplied cathodic protectioncurrent.

3.57 Insulating Flanges - Flanges which permitmechanical continuity but break the electricalcontinuity.

3.58 Interference - Interference is effect of straycurrent on electric parameters including potential of apipeline/structure.

3.59 Interference Bond - An intentional metallicconnection designed to control the electrical currentflowing between metallic systems.

3.60 IR Drop - Voltage difference caused betweentwo pointsofsoil/water electrolyte due to flow ofcurrent

3.61 Isolating Joint - Electrically insulatingcomponent such as monoblock insulating joint,insulating flange, isolating coupling, etc, insertedbetween two lengths of pipeline/structure to preventelectrical continuity between them .

3.62 Line Current - The direct current flowing ona pipeline/structure.

3.63 Long-Line Corrosion Activity - Currentflowing through the earth between an anodic and acathodic area that returns along an undergroundmetallic pipeline/structure.

3.64 Mixed Potential - A potential resulting fromtwo or more electrochemical reactions occurringsimultaneously on a metal surface.

IS 8062 : 2006

3.65 Natural Potential - Pipeline/structure toelectrolyte potential measured when pipeline/structureis completely depolar ized: (i) before the applicationof cathodic protection. and (ii) after switching offcathodic protection system.

3.66 On Potential- Pipeline/structure to electrolytepotential measured while cathodic protection systemis continuously operating.

3.67 Open Hole Deep Ground Bed - An installationin which the anodes are surrounded only by an aqueouselectrolyte.

3.68 Packaged Anode - An anode that whensupplied, is already surrounded by a selectedconductive material backfill.

3.69 Pipe-to-Electrolyte Potential - The potentialdifference between the pipe metallic surface andelectrolyte that is measured with reference to anelectrode in contact with the electrolyte.

3.70 Pipeline/Structure to Electrolyte Potential­Potent ial of a pipeline /structure with reference to astandard reference electrode located as close to thepipeline/structure as is practically permissible in theelectrolyte or soil.

3.71 Polarization - A shift in the potential of anelectrode resulting from a flow ofcurrent between theelectrode and the electrolyte surrounding it.

3.72 Polarization Cell - A d.c. decoupling deviceconsisting of two or more pairs of inert metallic platesin an aqueous electrolyte.

3.73 Polarized Drainage - A form of electricdrainage in which the connection between protected!affected pipeline/structure and source of stray currentsusually d.c. operated traction system of railwaysincludes a reverse current switch (usually a diode) forunidirectional flow of current.

3.74 Polarized Potential- The potential across thepipeline/structure/electrolyte interface that is thesum of the corrosion potential and the cathodicpolarization.

3.75 Primary Pipeline/Structure - The basicpipeline/structure to which cathodic protection is tobe applied, as distinct from a secondary pipeline/structure, on which interference takes place.

3.76 Protective Current - It is the total current tobe picked up on the pipeline/structure so that it reachesprotective potential.

3.77 Protective Potential - The potential of apipeline/structure with reference to a specifiedstandardreference electrode at which the corrosion rate of themetal is insignificant.

4

3.78 Rectifier - An electrical equipment forconverting a.c. from supply mains into d.c.

3.79 Remedial Bond - A bond between a primaryand secondary pipeline/structure to eliminate or reducecorrosion interaction .

3.80 Remote Earth - That part of electrolyte inwhich no measurable voltages, caused by current flow,occur between any two points.

3.81 Resistance Bond - A bond either incorporatingresistors or of adequate resistance in itself for thepurpose of limiting current flow.

3.82 Resistivity - Resistance between opposite facesof a unit cube of a substance usually given for a one­centimeter cube.

3.83 Reverse-Current Switch - A device thatprevents the reversal ofdirect current through a metallicconductor.

3.84 Safety Bond - A bond connecting metallicenclosure/framework of an electric equipment withearth to limit the rise of potential above earth in theevent of a fault.

3.85 Secondary Pipeline/Structure - A pipeline/structure not in view when cathodic protection isoriginally planned, but enters the picture as a result ofinterference.

3.86 Shielding - Preventing or diverting the cathodicprotection current from its intended path.

3.87 Shorted PipelinelStructure Casing - A casingwhich is in direct metallic contact with the carrier pipe.

3.88 Soil Resistivity - A measure ofthe physical andchemical characteristics of soil to conduct electricityexpressed in units of ohm-centimetres or ohm-metres.

3.89 Sound Engineering Practices - Reasoningexhibited or based on thorough knowledge andexperience, logically valid and having technicallycorrec~ premises that demonstrate good judgment orsense In the application of science.

3.90 Stray Current - Stray current is the currentthat is intended to flow in some other circuit and isreferred to as stray current when it flows in anunintended circuit.

3.91 Stray-Current Corrosion - Corrosionresulting from stray current transfer between the pipeand electrolyte.

3.92 Telluric Current - Current in the earth as aresult of geomagnetic fluctuations.

3:93 .Test Stations - Stations where cables fromplpelme/structure and other devices are terminated to

facilitate tests/measurement with regard to corrosionactivity, effect of cathodic protection and other current,performance of connected devices, etc.

3.94 Voltage - An electromotive force or a differencein electrode potentials expressed in volts.

3.95 Wire - A slender rod or filament of drawnmetal. In practice, the term is also used for smallergauge conductors.

4 ABBREVIATIONS

a.c. - Alternating current

CP - Cathodic protection

CSE Copper - Copper sulphate referenceelectrode

d.c. - Direct current

ICCP - Impressed current cathodic protection

TS - Test station

Yon Instant ON potential

Yoff Instant OFF potential

5 PIPELINE/STRUCTURE SYSTEM DESIGN

The following requirements should be considered,while designing the pipeline/structure system, so thatcathodic protection system can be implementedsuccessfully.

5.1 External Corrosion Control

External corrosion control must be a primaryconsideration during the design of the pipelines/structure system . Material selection and coatings arethe first line of defense against external corrosion.Cathodic protection is essential for a coated pipelinebecause perfect coatings are not feasible and allcoatings are subject to deterioration with time. Further,coating is not an essential requisite for the applicationofcathodic protection. Finally cathodic protection canbe applied at any stage during the design life of apipeline.

5.1.1 Materials and construction practices that createelectrical shielding should not be used on pipeline /structure.

5.1.2 Pipeline/structure should be installed at alocation where proximity to other pipeline/structureand surface formation will not cause shielding.

5.1.3 The depth of the pipeline/structure shall beadequate to have a uniform distribution of cathodicprotection current.

5.1.4 When two or more pipelines/structures arerunning in parallel and in close vicinity, the effect ofshielding should be avoided by relocating and spacingthe pipeline/structure properly.

5

IS 8062 : 2006

5.2 Electrical Isolation

Isolating devices should be installed within pipeline/structure system where electrical isolation of portionsof system is required to facilitate the application ofexternal corrosion control. Isolating joints should beprovided at: (a) both extreme ends of pipeline, and(b) all extreme ends of structure to be protected by acathodic protection system and should also beconsidered at following locations :

a) At points where pipeline /structure changesownersh ip such as metering stations. wellheads etc;

b) Between cathod ic protected pipel ine /structure;

I) Non-protected facilities such ascompressor or pumping station ,

2) Other pipel ine/structure with differentexternal coating/cathodic protectionsystem, and

3) Electric operated MOY and other suchinstallations connected with safetyearthing system.

c) lunction ofbranch lines. dissimilar metals etc;

d) Between normal pipeline/structure sectionand other pipeline/structure section that is;

I) Laid in different type of electrolyte, forexample, river crossing, and

2) Subject to interferences due to straycurrents .

e) On both sides of pipeline/structure laid overabove ground pipeline/structure such asbridges ;

f) Isolating joints shall be protected by usingelectrical earthing or surge arresters atlocations where pipeline/structure voltage dueto electric power system or lightening is likelyto exceed safe limits;

g) Internal surface of pipeline/structure on bothsides of insulating joint shall be suitablycoated for sufficient length to avoidinterference current corrosion in case ofpipeline/structure transporting conductivefluids;

h) Design, materials , dimens ions andconstruction of isolating joints should be inaccordance with specifications;

j) Design of cathodic protection system shouldinclude permanent facilities for: (a) testingeffectiveness of isolating joints, and(b) bonding of pipeline/structure isolatedsections as and where required;

k) Pipe surfaces on each side of such isolatingjoint should be protected from contact with

IS 8062 : 2006

soil for a distance of at least 50 times pipediameter in order to preventconcentrated flowof current from section to section around theinsulation. This protection is obtained mosteffectively by placing the pipe above groundon suitable supports; however. where such aplan is impracticable . an effective alternativeis to apply extra th ick coating along therequisite length of pipe and also completelyencase the isolating joints with the samecoating . Insulating joints should be paintedwith a distinct colour for easy identification;and

01) Care should be taken to see that the insulatedflanges are not short-circuited by chips ofmetal. dirt, etc. In certain cases this is ensuredby mounting over the flanges, shrouding boxesand then filling these boxes with bitumen.

5.3 Electrical Continuity

Cathodic protected pipeline/structure should beelectrically continuous for unimpeded flow of current.Necessary actions should be taken to ensure electricalcontinuity by providing permanent bonds acrossmechanical connectors, flange joints etc.

5.4 Test Stations

Test stations should be located at intervals along thepipeline/structure where they will be convenientlyaccessible to the corrosion engineer facilitate testingofcathodic protect ion parameters . Such locations mayinclude, but are not limited to the following:

a) Test stations shall be provided on both sidesof cased crossing , if width of cased crossingis more than 20 m;

b) Test station shall be provided on both sidesof river/canal, etc, if;

I) Isolating joints have been provided onboth sides or;

2) Width of river/canal is more than 50 01;

3) Pipeline/structure laying conditionsrequire the special monitoring ofPSP onboth sides of river/water crossing;

c) Crossing of two or more lines;

d) Only one test station shall be provided atIsolatingjoint with facilities for measurementof details for both sides of isolating joint;

e) Installation of a test station should also beconsidered at locations where pipeline passesthrough corrosive environment, such as:I) Stray current areas;

2) Valve stations;

3) Current drain p(lint;

6

4) Bridge crossings:

5) At close vicinity of foreign pipelineanode ground bed; and

f) A test station should be provided at locationswhere the pipeline/structure is connected with:

I) Earth electrodes for safety earthing and!or mitigation of a.c.ld.c . interference,

2) Galvanic anodes for cathodic protection ,and

3) Corrosion coupons.

5.4.1 From each test station at least two cables shouldbe connected to pipeline/structures. All cables shallbe identified by colour coding or tags .

5.4.2 Test leads from all pipeline/structure (includingforeign pipeline/structure) should be terminated at alltest stations in case of pipeline/structures are laid incommon right of way.

5.4.3 Pipeline/structure running parallel in commonright of way should not be bonded below the groundin the absence of any overriding consideration.Locations ofunderground bonding connections, ifanyshould be properly identified.

5.4.4 Pennanent test stations with cable connectionsto the pipeline/structure should be installedsimultaneously with the pipeline/structure to facilitatemonitoring of the performance of temporary cathodicprotection .

5.4.5 The spacing between test stations should notexceed I 500 m by considering the requirement ofconducting close interval potential logging survey thatuses continuous test wire between successive teststation. In urban or industrial areas , interval shouldnot be more than I 000 m.

5.4.6 Brazed connections includ ing thermit weldingprocesses should not be made within 150 mm of themain buttor longitudinal weld in high tensile steel pipe.The connection should be tested for mechanicalstrength and electrical continuity.

5.5 Road and Rail Crossings

As far as possible, cased crossings should be avoidedwherever they are not necessary. In India, it is~an~atory to cross railway tracks by using casing. Forpipeline/structure crossing under rail/road tracks, etc,an agreement would have to be made with theconcerned authorities.

No long pipeline/structure ca n avoid crossing of roadsand rails. Special precautions are necessarv at suchlocations to safeguard the carrier pipe by passing it~ro~gh an additional oversize pipe termed a 'Casingpipe . The section of the pipe thus encased in the

' Cas ing pipe' is termed as a 'Carri er pipe' . Casing pipesmay act as a shield to the flow of cathodic protectioncurrent to the carrier pipes thereby defeating theirprimary purpose of providing safety.

The section of carrier pipe inside the casing shouldhave the best possible standard of coating with as fewholidays as possible . The carrier pipe should beinsulated from casing pipe supported by plasticinsulating supports fitted to it at regular intervals. Thecarrier pipe inside the casing should be kept dry byuse of suitable end-seals and by filling the annulusbetween carrier and casing pipe with a suitableinsulating material such as wax, concrete slurry orpetroleum jelly. This will prevent future ingress ofwater in the annulus. Proper construction practices forcased crossings and proper fixing of end seals(including use of pressure type end seals) must beensured for preventing problems of electrical shortsbetween carriers and casing future ingress of water inthe annulus may be prevented.

5.5.1 Effectiveness ofelectric isolation between casingand carrier pipes should be tested at the time of layingof pipeline/structure and remedial actions should betaken simultaneously.

5.5.2 Corrosion protective coating on external andinternal surface of casing pipe can reduce magnitudeof current flow between casing and carrier pipesthrough soil/water inside the casing.

5.6 River Crossings

There are three alternate methods ofcrossing of riversand small streams:

a) Submerged crossings,

b) Suspended crossings, and

c) Use of existing road and rail pipe bridges.

For submerged crossings, care should be taken to givethe submerged section of the pipe the best possiblestandard of coating with as few holidays as possible.For the other two methods, the pipe should be insulatedfrom the metallic hangers, on which the pipes aresupported, by using suitable insulating material suchas neoprene sleeves. This is required only, if the pipealong the crossing is protected cathodically. On accountof the restrictions imposed by railway authorities,pipeline/structure over railway bridges are isolated byinstalling insulating flanges at both ends ofthe bridge.It should be noted that the flange towards the bridgeend should be insulated and not that at the main lineend.

5.6.1 For proper cathodic protection of concreteencased/cement weight coated pipeline/structure,rebars ofconcrete should be electrically isolated frompipeline/structure.

7

IS 8062 : 2006

6 PIPELINE/STRUCTURE EXTERNALCOATING

The function ofexternal coating is to control corrosionby isolat ing the external surface of the undergroundor submerged pipeline/structure from the environment,to reduce cathodic protection current requirements, andto improve current distribution . External coatings mustbe properly selected and applied and coated pipe shouldbe carefully handled and installed to fulfil thesefunctions. The follow ing types ofcoat ings are normall yused for high pressure cross-country undergroundpipeline/structure:

a) 3-layer polyethylene/polypropylene [seeIS 15569 (Part I)],

b) Fusion bonded epoxy [see IS 15569 (Part 2)],and

c) Coal tar enamel (see IS 10221).

7 CRITERIA FOR CATHODIC PROTECTION

External corrosion protection can be achieved atvarious levels of cathodic polarization depending onthe environmental conditions. However, in the absenceof specific data that demonstrates that adequatecathodic protection has been achieved one or more ofthe following conditions shall apply.

7.1 A negative (cathodic) potential of at least 850 mYwith the cathodic protection applied. This potential ismeasured with respect to a saturated copper/coppersulphate reference electrode contacting the electrolyte.Voltage drops other than those across the pipeline/structure-to -electrolyte boundary must be consideredfor valid interpretation of this voltage measurement.

Consideration is understood to mean the applicationof sound engineering practice in determining thesignificance of voltage drops by methods, such as:

a) Measuring or calculating the voltage drop(s);

b) Reviewing the historical performance of thecathodic protection system;

c) Evaluating the physical and electricalcharacteristics ofthe pipe and itsenvironment;and

d) Determining whether or not there is physicalevidence of corrosion.

7.2 A negative polarized potential of at least 850 mYrelative to a saturated copper/copper sulphate referenceelectrode.

7.3 A minimum of 100 mV of cathodic polarizationbetween the pipeline/structure surface and a stablereference electrode contacting the electrolyte. Theformation or decay ofpolarization can be measured tosatisfy this criterion. 100 mV Polarization potentialcriteria should be avoided under following conditions:

7.6.1 The hydrogen electrode is taken to be thestandard with reference to which other electrodepotentials are determined. It is inconvenient in practiceto use hydrogen electrode. Therefore, certain electrodesknown as reference electrodes are used in potentialmeasurements in the studies of corrosion and cathodicprotection. Potent ials of some usefu I referenceelectrodes are given below.

7.6.2 Potentials ofreference electrodes with referenceto standard hydrogen electrode at 25°C :

8 CATHODIC PROTECTION SYSTEM DESIGNOBJECTIVES

8.1 Major objective of cathodic protection systemdesign includes the following :

a) To provide sufficient current to the pipeline/structure so that selected criteria of cathodicprotection system is effectively achieved;

b) To minimize interference current on primaryand secondary/foreign pipeline/structure;

c) To provide a design life of anode systemcommensurate with the life of pipeline/structure;

d) To provide adequate allowance for anticipatedchange in cathodic protection currentrequirements with time; and

e) Adequate monitoring facilities to test andevaluate cathodic protection systemperformance.

8.2 Cathodic Protection Design Information

The following information is useful for designingproper cathodic protection system .

8.2.t Pipeline/Structure Design and Engineering Details

Details of pipeline/structure to be protected:

a) Material, length, diameter, wall thickness.

b) Design/Operating temperature and pressureand product to be transported.

c) Corrosion protective coating .

d) Design lifeofpipeline/structure and corrosionprotective coating.

e) Pipeline/structure route layout drawingsincluding but not limited to insolating joints.

IS 8062 : 2006

a) Higher operating temperature ;b) Electrolyte containing sulphate reducing

bacteria ;c) Pipeline/structure affected by stray currents;

andd) Pipeline/structure connected to/consisting of

components of different materials.

7.4 Special Conditions

7.4.1 On bare poorly coated pipeline/structure wherelone-line corrosion activity is of primary concern,the"'measurement of a net protective current atpredetermined current discharge points from theelectrolyte to the pipe surface, as measured by an earthcurrent technique, may be sufficient.

7.4.2 In some situations, such as the presence ofsu Ifides, anaerobic/aerobic bacteria, elevatedtemperatures, acid environments, and dissimilarmetals,the above criteria may not be sufficient and (-) 950 mVis to be applied.

7.4.3 To prevent damage to the coating, the limitingcritical potential should not be more negative than-I 200 mV referred to CSE, to avoid the detrimentaleffects of hydrogen production and/or a high pH atmaterial surface .

7.5 Other Considerations

7.5.1 Methods for determining voltage drops shouldbe selected and applied using sound engineeringpractice . Once determined, the voltage drops may beused for correcting future measurements at the samelocation, providing conditions such as pipe andcathodic protection system operating conditions, soilcharacteristics and external coating quality remainssimilar.

7.5.2 When it is impracticable or consideredunnecessary to disconnect all current sources to correctfor voltage drops in the pipeline/structure to electrolytepotential measurements, sound engineering practicesshould be used to ensure that adequate cathodicprotection has been achieved.

7.5.3 Situations involving stray currents and strayelectrical gradients may exist that require specialanalysis .

7.5.4 Where feasible and practicable, in-line inspectionofpipeline/structure may be helpful in determining thepresence or absence of pining corrosion damage.

7.6 Reference Electrode

An electrode whose open circuit potential is constantunder similar conditions of measurement used tomeasure the pipeline/structure to electrolyte potential.

8

Sl No.

(I)

i)ii)iii)iv)

Electrode

(2)

Saturated calomelSilver/silver chloride/saturated KCICopper/copper sulphateZinc/sea water

PotentialsVolts(3)

+0.24+0.22+0.32-0.78

IS 8062 : 2006

8.4 Types of Cathodic Protection

There are two methods of cathodic protection ofunderground pipeline/structure, namely:

a) Sacrificial anode system , and

b) Impressed current system .

8.4.1 Sacrificial (Galvanic)Cathodic ProtectionSystem

In the sacrificial anode system, sacrificial anodes basedon soil resistivity should be used as given in Table 2.The pipeline/structure remain in electrical contactwith the anode in the electrolyte. The performance ofany anode depends on composition and operatingconditions. Sacrificial anodes are limited in currentoutput by the anode to pipe/pipeline/structure drivingvoltage and electrolyte resistivity (see Fig. I) .

8.4.1.1 System design shall include calculations for:

a) Current requirement,

b) Design life of anodes, and

c) Resistance and output Current of anode(s).

8.4.1.2 Guideline for selection of galvanic anodecathodic protection system is given under 8.5.1.

8.4.1.3 Guidelines for selection of type of galvanicanodes , depth and distance between galvanic anodeand protected pipeline/structure are given in Table 2.Guidelines given in this table may not be followed ifengineering evaluation or field tests confirm that designrequirements can still be met by a different approach.

For galvanic anode systems, the following shall apply:

a) The resistivity ofthe soil orthe anode backfillshall be sufficiently low for successfulapplication galvanic anodes;

b) The selected type of anode shall be capableof continuously supplying the maximumCUrrent demand; and

c) The total mass of anode material shall besufficient to supply the required Current forthe design life of the system.

Galvanic anodes shall be marked with the type ofmaterial (for example trade name), anode mass(without anode backfill) and melt number. Fulldocumentation of number, types, mass, dimensions,chemical analysis and performance data of the anodesshall be provided. The environmental impact ofgalvanic anodes shall be considered.

Utilization factor for zinc and magnesium anode shallbe considered as given below :

f) Terminal and intermediate stations:

I) Road, railway and water crossings,2) Cased crossings,

3) a.c.Id.c. power lines and installations thatmay cause electric interference,

4) Possibility of telluric current activity,

5) Foreign pipeline/structure runningparallel to and/or crossing the pipeline/structure,

6) ICCP stations of foreign pipeline/structure, and

7) Availability of power supply at terminaland intermediate stations.

g) Required design life of (a) CP system forcurrent capacity, and (b) anodes.

h) Type of soil/resistivity and environmentalconditions.

8.2.2 Field Surveys and Data Collection

Details to be collected by field surveys as required fordesign of CP system:

a) Existing pipeline/structure - Current drain!Coating resistance test;

b) Soil chemical analysis for ionic and microbiaVbacterial loading;

c) Electric resistivity of soil at locations ofanodes; and

d) Specific details required for investigation andmitigation of interference problems.

8.2.3 Current Requirement

It is always better to use the protective currentrequirement data based on existing pipeline/structurewhich are being operated almost in the same type ofenvironment. As a general guidance, protective currentdensities given in Table 1 for various coatings may beconsidered as a requirement for newly coated pipeline/structure.

8.3 Temporary cathodic protection (TCP) isrecommended when construction period is more than3 months and soil resistivity is less than 100 ohm-m.While designing TCP the current density should be atleast 50 percent of the values given in Table I.

Table 1 Protective Current Density for NewlyCoated Pipeline/Structure

(Clauses 8.2.3 and 8.3)

SI Soil 13 LPEI IFBEI Coal TarNo. Resistivity Coated Pipe Coal Pipe Enamel

ohm-m I1Nml I1 N ml I1N ml

(I ) (2) (3) (4) (5)i) 10-100 25 50 125ii) <10 50 70 150i ii) >100 15 25 75

9

UtilizationFactor

Zinc (Zn)Magnesium (Mg)

CentreConnected

0.850.88

EndConnected

0.50.6

IS 8062 : 2006

Table 2 Sacrificial Anodes

(Clauses 8.4. 1 and 8.4.1.3)

SI Anode Soil Resistivity Distance from Pipe Minimum DepthNo. ohm-m

(I) (2) (3) (4) (5)

i) Zinc (Zn) < 10 2 1.2i i) Magnesium > 10-45 5 1.2iii) Ribbon (Mg) > 45-100 0.5 1.2

rasr STATION

t -

--•

~-----------+--- PROTECTIVE CURRENT +++MAGNESIUM

FIG. I GALVANIC/SACRIFICIAL ANODE S YSTEM

8.4.1.5 Magnesium anodes

Magnesium anodes shall be performance-tested inaccordance with ASTM G 97. The values obtainedfrom the testing shall be the basis for the design of thesystem. A typical composition of magnesium anodesis given in the following Table 4.

Table 4 Typical Chemical Composition ofthe Standard Alloy Used for Magnesium Anodes

Max(4)

0.026.70.10.003

0.0023.5

5.3

(3 )

0.15

Min

CompositioD of Mass FrutioD,Pereeet

.-- .A.-.... ......

ElellleatSINo.

( I) (2)

i) Cuii) AIiii) Siiv) Fev) Mnvi) Nivii) Zn 2.5viii ) Mg Remainder

NOTE - The.max imum amount of other elements shall be0.005 percent (mass fraction) each.

NOTE - The max imum amoun t of other elements shall be0.02 percent (mass fraction) each.

Table 3 Typical Chemical Composition of theAlloy Used for Zinc Anodes

SI Ele ment Compositi oDof Mass FractioD,No. Pereear

r..... ,

Min Max(I ) (2 ) (3) (4)

i) Cu 0.005ii) AI 0.10 0.50iii) Fe 0.00 5iv) Cd 0.07v) Pb 0.006vi) Zn Remainder

8.4.1.4 Zinc anodes

A typ ical composition of zinc anodes is given inTable 3.

;J ther (; :loys may beused provided the performance insimilarsoils is reliable and documented.

10

Other alloys may be used provided the performance insimilar soils is reliable and documented.

8.4.1.6 Anode backfill

Anode backfill for galvanic anodes should consist of amixture of gypsum, bentonite clay and sodiumsulphate. The specific composition of the anodebackfill shall be determined by the need to minimizeresistivity and maximize moisture retention.

The required composition ofthe anode backfill materialshall be included in the anode specification.

8.4.2 Impressed Current Cathodic Protection System

A direct current impressed on a pipeline/structure froman external power source for providing cathodicprotection to it. Impressed current system contains d.c.power equipments, anode ground bed and other relateditems. A typical illustration of an impressed currentcathodic protection system is shown in Fig. 2.

8.4.2.1 Guidelines for selection of impressed currentcathodic protection system are given under 8.5.2.System design shall include calculation for:

a) Current requirement,

b) Zone of protection of lCCP Station,

c) Resistance and design life anode ground bed,and

d) d.c. output voltage and current rating of d.c.power equipment.

8.4.2.2 Anode ground beds

8.4.2.2.1 General

The anode ground beds of an impressed-current CPsystem for cross country pipeline should be eitherremote deep well or remote shallow type. These shouldbe designed and located so as to satisfy the following:

a) Mass and material quality shall be suitablefor the specified design life of the CP system,

b) Resistance to remote earth ofeach ground bedshall allow the maximum predicted currentdemand to be met at no more than 70 percentof the voltage capacity of the d.c . sourceduring the design life of the CP system . Thecalculation shall be carried out for the unusedanode bed at the end of life, and

c) Harmful interference on neighboring buriedstructures shall be avoided .

In selecting the location and type ofground beds to beinstalled , the following local conditions shall be takeninto account:

a) Soil conditions and the variation in resistivitywith depth,

11

IS 8062 : 2006

b) Ground water levels ,

c) Any evidence of extreme changes in soilconditions from season to season ,

d) Nature of the terrain,

e) Shielding (especially for parallel pipelines).and

f) Likelihood of damage due to third partyintervention.

The basic design shall include a calculation of theground bed based upon the most accurate soil resistivitydata available .

The current output from anodes should beindependently adjustable .

8.4.2.2.2 Deep-well ground beds

Deep-well ground beds should be considered where :

a) Soil conditions at greater depth are far moresuitable than at surface,

b) There is a risk of shielding by adjacentpipelines or other buried structures.

c) Available space for a shallow ground bed islimited, and

d) There is a risk of interference current beinggenerated on adjacent installations.

The detailed design shall include a procedure for drillingthe deep well, establishing the resistivity of the soil atvarious depths, completing the borehole and method ofinstalling the anodes and conductive backfill .

The borehole design and construction shall be suchthat the undesirable transfer ofwater between differentgeological formations and the pollution of underlyingstrata is prevented.

Metallic casings should be used for stabilizing theborehole in the active section of the ground bed. Themetallic casing shall be electrically isolated from anystructures on the surface. Metallic casings only providetemporary borehole stabilization, as the metal will beconsumed by the d.c. current flow.

If permanent stabilization is required, non-metallic ,perforated casings should be used.

In the calculation of the ground bed resistance, the soilresistivity data corresponding to the depth at the mid­point of the active length shall be used and thepossibility of multi-layered soils with significantlydifferent soil resistivity considered.

Deep-well ground beds should be provided withadequate vent pipes to prevent gas blocking betweenanode and the conductive backfill. Vent pipe materialshall be manufactured from the non-metallic chlorine­resistant material.

,

IS 8062 : 2006

220V SUPPLY

PIPE LINE

REFERENCEELECTRODE

~ 100 metre

* DISTANCE AS PER DESIGN

s· s· S·

FIG. 2 I MPRESSED CURRENT A NODE S YSTEM

8.4.2.2.3 Shallow ground beds

Shallow ground beds should be considered where :

a) Soil resistivities near the surface are far moresuitable than at the depths of a deep-wellground bed.

b) There is no risk of shielding by adjacentpipelines or other buried structures.

c) Space is available for a shalIow ground bed.

d) There is no risk of interference current beinggenerated on adjacent instalIations.

Shallow ground bed anodes shalIbe instalIedhorizontalIyor verticalIy. In either case, the top of the conductivebackfill shalI be at least 1.5 m below ground level.

In the calculation ofthe ground bed resistance, the soilresistivity da ta corresponding to the centre-line(horizontal ground bed) or mid-point (vertical groundbed) ofthe anodes shall be used and with the possibilityof multi -layered soils with significantly different soilresistivities considered.

The detailed design shall include a procedure for theconstruction of the ground bed and for the installationof the anodes and the conductive backfill.

a) High-silicon iron alIoy, including chromiumadditions, in soils with high chloride content;

b) Magnetite;c) Graphite;d) Mixed-metal-oxide coated titanium;e) Platinized titanium/niobium;t) Conductive polymers; andg) Steel.

Alternative materials may be used, if theirperformances relevant to the specific operatingconditions are reliable and documented.

The specific material, dimensions and mass shalI deliver125percent ofthe required anode current output requiredfor meeting the specified design life of the CP System.

A carbonaceous or other conductive backfill materialshall be used unless the soil conditions give a satisfactoryground bed resistance, the soil is homogeneous anduniform consumption of anodes is expected.

The environmental impact of the dissolution of anodematerials and breakdown of the conductive backfillmaterial shall be considered. Utilization factor forMixed Metal Oxide and High Silicon Anodes are asgiven below:

8.4.3 Impre ssed-Current Anodes and ConductiveBackfill

Anode materials should be selected from the folIowinglist:

12

UtilizationFactor

Mixed metal oxide (MMO)High silicon

CentreConnected

0.800.80

EndConnected

0.900.6

Use of continuous conductive polymer anodes shouldbe considered, particularly for very high resistivity soilssurrounding the pipeline.

8.4.4 Sources 0/Power

A d.c . supply needed for cathodic protection is suppliedusing Transformer Rect ifier Unit (TRU) or CathodicProtection Power Supply Control Module (CPPSM).

The input source of power for Transformer RectifierUnit (TRU) or Cathodic Protection Power SupplyControl Module (CPPSM) is generally state grid. Wherestate grid power supply is not reliable or available, thefollowing power sources are generally used:

a) Closed cycled vapour turbo alternator (CCVT),

b) Thermo electric generator (TEG),

c) Solar power,

d) Wind power,

e) Diesel generator, and

f) Any other reliable source of power.

While selecting the power source for cathodicprotection system, following considerations should betaken into account:

a) Reliability,

b) Maintenance requirement,

c) System life,

d) Initial cost,

e) Type offuel, and

f) Operating cost.

8.4.5 Current Output Control and Distribution

The impressed-current output should be controlled bythe output voltage on TRU/CPPSM and correspondingpotentials measured along the pipeline.

8.4.5.1 Current distribution/or multiple pipelines

Where there is more than one pipeline to be cathodicallyprotected, the current return from the pipelines shouldbe independently adjustable. In such cases, the pipelinesshall be isolated from each other and provided with anegative connection to the current source .

Res istors should be installed in the negative drains tobalance the current to each of the adjacent pipelinesindividually. Each negative drain shall be providedwith a shunt and diode preventing mutual influence ofpipelines during on-potential and off-potential

measurements.

All cables, diodes and current measurement facilitiesshould be installed in a distribution box.

8.4.5.2 Automatic potential control

The d.c. voltage source can beprovided with automatic

13

IS 8062 : 2006

potential control which shall be linked to a permanentreference electrode buried close the pipeline. Referenceelectrodes shall be regularly calibrated.

The potential measuring circuit shall have a maximuminput resistance of 100 mil. The electronic controlsystem shall have an accuracy of ± 10mV and beprovided with adjustable voltage and current-limitingcircuits and alarms to protect the pipel ine againstpolarization outs ide the established criteria in the eventthat reference electrode fails . A panel-mounted metershould be provided to enable the reading of pipe-to­soil potential

8.4.5.3 Automatic current contra!

The d.c. voltage source can be provided with currentcontrol to set output current to the pipeline or the anodesystem.

Automatic current control alone shall not be used forsetting current flow where soil moisture or othervariat ions near the pipeline can cause potentialvariations.

8.5 Choice of Method for Cathodic Protection

The choice between the two systems of cathodicprotection, namely, sacrificial anode and impressedcurrent depends on a detailed assessment of thetechnical and economic factors involved. Generally,sacrificial anode cathodic protection system is usedfor temporary protection of pipeline/structure tillpermanent cathodic protection system is commissionedand reliable power supply is arranged . However. thechoice between the two systems depends on thefollowing factors:

a) Magnitude of current required for cathodicprotection,

b) Electrical resistivity of electrolyte.

c) Design life of cathodic protection system,

d) Availability and rel iability of poweravailability of space for anode installation.

e) Requirements of CP system monitoring andcontrol, and

f) Future developments.

8.5.1 Galvanic Anode System

a) Galvanic anode system is usually provided for:

I) Small diameter pipeline/structure or well­coated pipeline/structure requiring smallcurrent in low resistivity soils, water,swamps/marshes, and

2) Temporary cathodic protection ofpipeline/structure until permanentimpressed current system is commissionedand reliable power supply is arranged.

IS 8062 : 2006

b) Application of galvanic anode system isconsidered where :

I) No power for impressed current isavailable or available power is notreliable or ma intenance of electricalsystem is not possible,

2) Application of remote impressed currentsystem can not be provided due tolimitations of space or otherconsiderations,

3) Impressed current system is to besupplemented for localized (hot spot )protection, and

4) Application of impressed current systemmay create unmanageable interferenceproblems for other nearby pipeline/structure.

8.5.2 Impressed Current System

a) Impressed current system should bepreferably provided for cathodic protectionof pipel ine/structure unless application ofgalvanic anode system is required due tofactors given under preceding sub-clauses andother overriding considerations; and

b) The following factors should also be taken intoaccount for sites of impressed current systems:

1) Availability and reliability of powersupply and suitable location forinstallation of d.c. power equipment;

2) Availability ofproper site for installationof prospective anode ground bed,keeping in view effects of: (i) electricalresistivity of soil and surface and sub­soil conditions, and (ii) distance betweenpipeline/structure and remote ground bedon current distribution and performanceof anode ground bed; and

3) Effects of proposed system on existingand future pipeline/structure ofthe ownerand others and other developments.

9 CONSTRUCTION AND INSTALLATION OFCATHOmC PROTECTION SYSTEM

9.1 General

All construction and installation works of cathodicprotection systems should be performed in accordancewith approved construction drawings, specificationsand procedures under the surveillance of trained andcompetent personnel to verify that all installations arein strict accordance with approved documents and well­established practices.

9.2 The construction and installations works at siteshall include but not limited follow ing activities :

14

a) Physical inspection of all equipment/materialson receipt at site to confirm that all equipment!materials are in accordance with despatchdocuments/specifications/drawings and havenot got damaged during transport to site ;

b) Proper storage of equipment to ensure thatno damage is caused to equipment/materialsduring stora ge at site;

c) Pre-installation inspection/tests/measurementsto confirm that all equipment/materials arein accordance with approved drawings/specifications;

d) Inspection dur ing/after installation to confirmthat all equipment/materials are installedin accordance with approved drawings,specifications/procedures and well-acceptedpractices; and

e) Pre-commissioning inspection, test/measurements to confirm that ;

I) AIIequipment/materials/installations allfree from physical defects/damages,

2) All accessories and devices have beenproperly installed and connected,

3) All cables have been properly installedand terminated,

4) Electric Resistance of all circuits andInsulation Resistance of all cables are asrequired, and

5) Results of recommended pre­commissioning tests/measurements forall eq u ipment/ insta llat io ns are inaccordance with requ irements for finalcommissioning ofequipment/installation.

f) Equipment/Installation Commissioning Tests!measurements in accordance with approved!specified procedures, and

g) CP System commissioning tests/measurementsin accordance with approved/specifiedprocedures.

9.3 A comprehensive coverage of all activities andconstruction pract ices is not feasible within frameworkof this standard. Other sections of this standard alsoinclude some specific requirements/recommendationsfor installat ion, testing and commissioning.

10 ELECTRIC INTERFERENCES

10.1 General

Corrosion caused by interference current on buriedmetallic pipeline/structures differs from other causesof corrosion, in that the current which causes thecorrosion has a source foreign to the affected pipeline/structure. Usually , the interfering current is derivedfrom a foreign source, not electrically continuous with

the affected pipeline/structure , or is drained from thesoil by the affected pipeline /structure. Detrimentaleffects of interference currents occur at locationswherethe currents are subsequently discharged from theaffected pipeline/structure to the earth.

Sources of direct current interference are:

a) Constant current sources , such as from CPrectifiers, and

b) Fluctuating current sources, such as d.c.electrified railway systems and transitsystems, coal mine haulage systems andpumps, welding machines and direct currentpower systems.

Types of a.c. interference are:

a) Short-term interference caused by faults ina.c. power systems and electrified railways,

b) Long-term interference, caused by inductiveor conductive coupling between the pipeline/structure and high-voltage lines or electrifiedrailways, and

c) Telluric currents interference.

10.2 Direct Current Interference

10.2.1 Measurements

In areas where d.c. interference currents are suspected,one or more of the following should be performed:

a) Measure pipe-to-soil potentials with recordingor indicating instruments;

b) Measure current density on coupons;

c) Measure current flowing on the pipeline/structure with recording or indicatinginstruments; and

d) Measure variations in current output of thesuspected source of interference current andcorrelate them with measurements obtainedas above.

The measurements should be carried out for a periodof 24 h, or a period which is typical for the suspectedinterference phenomenon being investigated, to assessthe time dependence of the interference level.

Interference with other buried pipeline/structures orinstallations should be measured while the CP systemis energized. Interference measurements shouldgenerally include following:

a) Measure both the foreign pipeline/structureand the interfered pipeline/structure pipe-to­soil potential while the relevant sources ofCPcurrent that can cause interference aresimultaneously interrupted; and

b) Measure the pipe-to-soil potential at the other

15

IS 8062 : 2006

pipeline/structure or installation while the CPsystem is energized.

10.2.2 Criteria for Corrosion Interference

Positive potential changes are liable to acceleratecorrosion. Negative potential changes provide cathodicprotection but excessive negative potential is liable toadversely affect corrosion protective coating. Safetyof equipment and personnel are endangered if changeof potentials and/or current flow due to interferencesresults in higher than permissible limits for safety ofequipment and personnel. Therefore necessary actionsare required to betaken for investigation and mitigationof interferences in accordance with specified criteriaand recommended practices .

a) Pipeline/Structure to Electrolyte d.c.Potentials

Pipeline/structure is considered to beeffectively protected by cathodic protectionsystem if pipeline/structure to electrolytepotential is within limits specified under 7.

b) Notwithstanding pipeline/structure toelectrolyte d.c. potentials being within limitsfor effective cathodic protection, interferencesresulting in more than 50 mV change of d.c.pipeline/structure to soil potential. Potentialsshould be investigated by owner/s ofaffectedpipeline/structure and remedial actions shouldbe taken.

10.2.3 Mitigation of d.c. Interference CorrosionProblems

Common methods to be considered in resolvinginterference problems on pipeline/structures or otherburied structures include:

a) Prevention of pick-up or limitation of flowof interfering current through a buriedpipeline/structure,

b) A metallic conductor connected to the return(negative) side of the interfering currentsource,

c) Counteraction ofthe interfering current effectby means of increasing the level of CP, and

d) Removal or relocation of the interferingcurrent source .

NOTE - Cooperation and exchange of infonnationbetween owners of pipeline affected by interference isessential as d.c. interference between pipeline isconstantly evolv ing phenomenon .

10.2.3.1 Specific methods to be considered,individually or in combination are as follows:

a) Design and installation ofmetallic bonds witha resistor in the metallic bond circuit betweenthe affected pipeline or other structures.

IS 8062 : 2006

The metallic bond electrically conductsinterference current from an affected pipeline/structure to the interfering pipeline/structureand/or current source;

b) Application ofuni-directional control devices,such as diodes or reverse current switches;

c) Coating the bare pipe where interferencecurrent enters the pipeline/structure;

d) Application of additional CP current to theaffected pipeline/structure at those specificlocations where the interferingcurrent is beingdischarged;

e) Adjustment of the current output frommutually interfering CP rectifiers;

f) Reduction or elimination of the pick-up ofinterference current by relocation/redesign ofthe ground bed such that it is electricallyremote;

g) Installing properly located isolating joints inthe affected pipeline/structure. Testing at theisolating joint should be done to assure thatan interference condition has not then beenintroduced;

h) Improvement in the protective coating on theinterfering structure ; and

j) Installation of isolating shields between thepipeline/structure and the interferingstructure.

NOTE - While installing isolat ing joints will reduce themagnitude of the stray current, it also introduces anothercurrent pick-up and discharge location , hence the reason fortesting at the isolating joint.

10.3 Alternating Current (a.e.) Interference

10.3.1 General

The magnitude ofpermanent or short-term iriterferenceon a pipeline/structure from high-voltage a.c. sourcessuch as power lines and electrified railways mainlydepends on:

a) Length of parallel routing,

b) Distance from the pipeline/structure,

c) a,c. line voltage level,

d) a,c, line current level,

e) Pipeline/structure coating quality, and

f) Soil resistivity.

a.c. interference effects on buried pipeline/structurescan cause safety problems. Possible effects associatedwith a.c . interference to pipeline/structures includeelectric shocks, damage to coating, acceleratedcorrosion and damage to insulators.

10.3.2 Assessment ofa.c. Induction

a.c. interference can be assessed by taking intoconsideration data from the affected pipeline/structure

16

such as coating resistance, diameter, route , andlocations of isolating joints or isolating flanges andhigh voltage a.c. system data. This assessment may bedone by a suitable simulation of system conditions. Ifthe isolating device is bonded across, such that thepipeline/structure is electrically continuous with a plantearthing grid, then either the resistance-to-earth of thegrid shall be estimated or the grid itselfshall be part ofthe study.

For a.c. traction systems, data to be considered are theinterfering high voltage, operating current, location andlayout of the high-voltage tower and position of thewires, route (including the position of thetransformers), frequency and electrical characteristicsfor high-power lines.

Results of test measurements for existing pipeline insame corridor should be considered for realisticassessment of a.c. induction.

To determine the a.c. corrosion risk, coupons shouldbe installed where the a.c. influence is expected. Theyshould be buried at the pipeline/structure depth andhave adequate equipment for current measurements.It should also be considered to install additionalcoupons wh ich can later be removed for visualexamination.

The a.c. current density within a coating defect is theprimary determining factor in assessing the a.c .corrosion risk. In case of low soil resistivity , high a.c.current densities can be observed.

In sections where a.c. voltages are higher than 10 V,or where voltages along the pipeline/structure showvariation to lower values, indicating possible a.c .discharge , additional measurements should beperformed on site.

No single measuring technique or criterion for theevaluation ofa.c. corrosion risk is recognized to assessa.c. corrosion .

More specific measurements include:

a) Pipe-to-soil potential,

b) Current density, and

c) Current density ratio (a.c. current densitydivided by d.c. current density) .

NOTE - If the a.c. current density on a I()() mm' bare surface(for example an external test probe) is higher than 30 Aim! (orless, in certain conditions), there is a risk ofcorrosion. Risk ofcorrosion is mainly related to the level of a.c. current densitycompared to the level ofCP current density. Iftbe LC . currentdensity is too high, the a.c. corrosion cannot be preventedbyCP.

10.3.3 .Limiting a.c. Interferences

The maximum step and touch voltage shall be limited

in accordance with local or national safety requirements. and shall be adhered to at all locations where a personcould touch the pipeline/structure.

Protection measures against a.c. corrosion should beachieved through the following measures :

a) Reduce the induced a.c. voltage ; and

b) Increase the CP level so that the positive partof a.c, current can be neglected.

To reduce a.c . voltage, the following methods shouldbe considered:

a) Install pipeline/structure earthing equippedwith suitable devices in order to let d.c. butnot a.c. flow . A simulation on a computermight be required to optimize the number,location and resistance-to-earth of theearthing systems.

b) Install active earthing-potential-controlledamplifiers to impress a current into thepipeline/structure, compensating or reducingthe induced voltage. This method should beapplied, if the required reduction of inducedvoltage cannot be achieved by simpleearthing. The location of compensationdevices shall be carefully considered.

c) Add earthing systems to provide potentialequalization at local areas. These earthingsystems can be constructed using a widevariety of electrodes (galvanized steel, zinc,magnesium, etc). Some earthing systems canhave an adverse effect on the effectivenessof the CPo To avoid adverse effects on theCP, the earthing systems should be connectedto the pipeline/structure via appropriatedevices, (for example spark gaps, d.c.decoupling devices, etc).

Shifting the d.c. voltage level to reach more negativepotential can reduce the a.c. corrosion rate. The pipe­to-soil potentials should not be more negative thanthose given in 7.

11 OPERATIONS AND MAINTENANCE

11.1 Routine for Measurements

11.1.1 The direct current voltage and current outputsofthe transfonner/rectifier and pipe/pipeline/structureto soil potential at drain points should be monitored atleast once a fortnight These measurements verify thesatisfactory operation ofthe transformer rectifiers, theground beds, and the connecting cables. The surveyfor monitoring ofperformance CP stations should alsoinclude at least the following:

a) Permanent reference electrodes to soilpotentials;

17

IS 8062 : 2006

b) Currents of anode circuits at anode junctionbox;

c) Pipeline/structure currents at cathode junctionbox;

d) Input/output/performance parameters ofpower supply devices CCVT/BanksITEG/Solar panel; and

e) Performance parameters of specific devicesprovided for monitoring power supply,remote monitoring/control, etc.

11.1.2 Measurements ofpipe-to-soil potential shouldbe taken monthly at vulnerable points where access iseasy and on quarterly basis at all test points . Theremay be a seasonal variation in potential, which canbe compensated for by increase/decrease of theappropriate transformer/rectifier settings. The surveyof test stations should also include at least followingtypical tests/measurements at regular intervals:

a) Line current measurements;

b) Anode to soil potential and output current ofgalvanic anodes of temporary cathodicprotection system;

c) V""Nalf pipeline/structure to soil potentials;

d) Foreign pipeline/structure to soil potentialsand current through bonding connection, ifprovided;

e) Coupon to soil potentials and coupon current;and

f) Earthing resistance of earth electrodes.

11.2 Where stray current problem exists, morefrequent checks may be made. Results provided byremote monitoring system should be periodicallychecked against manually recorded data to ensure thatremote monitoring system is functioning correctly.

11.3 Surveys During Operation and Maintenance

Various specialized survey techniques are available,without requiring any direct access to the pipeline/structure metal surface, to assess the protective systemadequacy, non-destructively. Usually, each of theseprovides different information although there is someoverlap. The specific requirements of a pipeline/structure need be considered while selecting surveytechniques or a combination of surveys.

11.3.1 Close-Interval Potential Survey (CIPS)

CIPS can be used to determine the level of CP alongthe length ofthe pipeline/structure. It can also indicateareas affected by interference and coating defects . Thepipe-to-soil potential is measured at close intervals(typically I m) using a high-resistance voltmeter/microcomputer, a reference electrode and a trailingcable connected to the pipeline/structure at the nearest

IS 8062 : 2006

monitoring station. Measurements of potential areplotted versus distance from which features can beidentified by changes in potential caused by localvariations in CP current density. The survey may becarried out with the CP system energized continuously(an ' on-potential' survey) or with all transformer­rectifiers switching offand on simultaneously with theaid of synchronized interrupters.

Because a large amount of data is produced, a fieldcomputer or data logger is normally used and theinformation later downloaded to produce plots ofpipeline/structure potential versus distance from thefixed reference point.

11.3.2 Pearson Survey

Pearson surveys locate defects in the protective coatingof a buried pipeline/structure.

An a.c . voltage is applied between the pipeline/structure and remote earth, and the resulting potent ialdifference between two contacts with the soilapproximately 6 m apart is measured. Two operatorswalk along the route, making the necessary contactswith the soil , usually via cleated boots . They walkeither in-line directly over the pipeline/structure orside-by-side with one operator over the pipeline/structure. An increase in the recorded potentialdifference can indicate a coating defect or a metallicobject in close proximity to the pipe.

The in-line method is helpful in the initial location ofposs ible coating defects, since any increase in potentialdifference (usually determined by an increase in anaudio signal) is obtained as each operator passes overthe defect. However, when there is a series of defectsclose together, and specific information on a particulardefect is required. the side-by-side method is preferred.Interpretation of the results obtained is entirelydependent on the operator, unless recording techniquesare used .

11.3.3 Current Attenuation Survey (CAl)

Current attenuation surveys can be used to locatedefects in protective coatings of buried pipeline/structure. The method is similar to the Pearson Surveytechnique in that an a.c. voltage is.applied to the pipe,but a search coil is used to measure the strength ofthemagnetic field around the pipe resulting from the a.c.signal.

Current attenuation surveys are based on theassumption that when an a.c. signal flows along astraight conductor (in this case the pipeline/structure),it will produce a symmetrical magnetic field aroundthe pipe. The operator uses the electromagneticinduction to detect and measure the intensity of thesignal using an array of sensing coils carried through

18

the magnetic field to compute pipe current. Where theprotective coating is in good condition, the current willattenuate at a constant rate, which depends uponcoating properties. Any significant change in thecurrent attenuation rate could indicate a coating defector contact with another pipeline/structure.

11.3.4 Direct Current Voltage Gradient Survey(DeVO)

A DCVG survey can be used to locate and establishthe relative size of defects in protective coatings onburied pipelines . By applying a direct current to thepipeline/structure in the same manner as CP, a voltagegradient is established in the soil due to the passage ofcurrent to the bare steel at coating defects. Generally,the larger the defect, the greater the current flow andvoltage gradient.

A current interrupter should be installed at the nearesttransformer rectifier or a temporary current source toachieve a significant potential change (approximately500 mV) on the pipeline/structure.

Using a sensitive millivoltmeter, the potentialdifference is measured between two referenceselectrodes (probes) placed at the surface level in thesoil within the voltage gradient. Defects can be locatedby zero readings corresponding with the probes beingsymmetrical either side of the defect. In carrying outthe survey, the operator walks the pipeline route takingmeasurements at typically 2 m intervals with the probesone in front ofthe other, I m to 2 m apart. The probesare normally held parallel to and directly above thepipeline, enabling the direction of current flow to thed~fect to be determined. Making transverse readingsWIth one electrode locate at the epicenter ofthe coatingdefect, anodic and cathodic characteristics can bedetermined.

11.4 Faults and Remedies

11.4.1 Electrical faults may occur in the bodies of theanode material due to excessive Current. Anode failuremay also occur due to a faulty seal on the connection.The anode in question may be located by traversingalong the ground bed with a voltmeter and two halfcells and should be replaced.

11.4.2 Cable faults which may occur due to various~ason~, namely , mechanical damage, deterioration ofmsulatlOnwhich for positive cable will result in rapiddeterio~ation of the conductor can be found byexcavation and inspection. The cables should bejointedor replaced.

11.4.3. Sudden local changes in the pipe-to-soil~te~hal readings may be due to many causes, thepnnclpal ofwhich are: .

a) Local flooding - Transformer/rectifiersetting should be readjusted.

b) Severe local coating damage or deterioration.The damaged coating should be locatedeither by visual examination or by use of thePearson holiday detector/CAT survey/DCVG survey and bore hole inspection madegood; and

c) When a casing is short-circuited to the pipethe potential on the pipe is expected to berelatively less negative, and it could even beless negative than the accepted value in oraround the point ofshort. The current drawnfrom the rectifier system is expected tosuddenly increase. When this isnoted the endsofthe casing would then have to be excavatedand the cause of the 'short' found andremoved. Where tests indicate that the pointof contact is well back from the end of thecasing, the chances are that it cannot becleared with any reasonable effort andexpense by working from the casing ends. Tosafeguard the carrier pipe inside such 'non­clearable' casings, any of the followingmethods may be adopted:

I) To fill the entire annular space betweenpipe and casing with a material that willstifle any corrosion tendency. Proprietarycasing compounds (greases containingchemical inhibitors) or unrefinedpetroleum (low in sulphur content) maybe used, and

2) To install magnesium anodes on bothsides of the line at each end of thecasing.

12 SAFETY PRECAUTIONS

12.1 General

Safety precautions mentioned under this clause andall other safety precautions as required for cathodicprotection works and installations in hazardous/non­hazardous areas shall be taken to ensure safety ofequipment and manpower.

12.1.1 Safety precautions for rectifiers, switches andcables are the same as for any other electricalappliances.

12.1.2 The lowered potential ofcathodically protectedstee I pipeline/structure with reference to thesurroundings means that contact with another steelpipeline/structure which will normally be at zeropotential may produce a spark. It is recommended,therefore, that every precaution should be taken toavoid such sparking.

19

IS 8062 : 2006

12.2 Danger of Electric Shocks

Voltages in excess of 50 V d.c. are seldom used forcathodic protection, thus the danger from electricalshock is very unlikely. Safety procedures should beadopted to switch off the cathodic protection orinstallation of grid earthing while working on thepipeline/structure during cutting, tapping, etc. It isfurther advisable to put a temporary bond around theline before starting the work on the line and this bondallowed to remain till the job is finished. This bondshould be no less in size than standard welding cableand provided with suitable clamps . Attention shouldalso be paid to the danger ofpossible harm to life nearthe ground beds due to the voltage gradient at thesurface of the soil. It should be ensured that:

a) d.c. output of the rectifier transformer shouldnot exceed 50 V d.c., and

b) Leads are fully insulated and protected againstmechanical damage.

12.3 Fault Conditions in Electricity Power Systemsin Relation to Remedial and/or Unintentional Bonds

There is a possible risk in bonding a cathodic protectionsystem to any metal work associated with the earthingsystem of an electricity supply network, especially inthe vicinity of high voltage sub-stations. Therefore,such bonding should not be accepted as a general rule,any exception to it being made by the corrosionengineer himself, after competent tests.

12.3.1 Bonds between metal work, associated with anelectricity power system (for example, cable sheath)and cathodically protected pipeline/structure, cancontribute an element of danger when abnormalconditions occur on the power network. The principaldanger arises from the possibility of current flow,through the bonds, to the protected pipeline/structure,due to either earth-fault conditions or out-of-balanceload currents from the system. This current, togetherwith the associated voltage rise, may result in electricshock, explosion , fire, overheating and also risk ofelectrical breakdown of coatings on buried pipeline!structure. Such hazards should be recognized bythe parties installing the bond and any necessaryprecautions taken to minimize the possibleconsequence . The rise in temperature of conductors,joints and accessories is proportional to Pt, where 1 isthe fault current and t its duration. Bonds should berobust enough so that they may withstand, withoutdistress, the highest value ofP t, expected under faultconditions . For extreme conditions, duplicate bondingis recommended.

12.4 Installations in Hazardous Areas

12.4.1 Cathodic protection can introduce hazards in

IS 11062 : 2006

are.." lfl ~hl\;h an mllamm..ble mixture of 8M, vapourur dU"l (lhilt l1 huardou.' atmosphereJ may be present~hlch cou ld be Ignited by an electric MC or spark.. In a

cathod ic protection system. 4 'park may be caused byone or more of the following reasons'

a) Drsconnectlon of bonds .crOB pipeline/structure jOllttt;

b) Shan-circuit or isolating joints. fOf example,by tools lying ICrOM I joint Of breakdown dueto voltage surges on the pipeline/structureInduced by Iichbung or electrical switching,urin,

e) Disconnection Of breakage of cable carryingcathodIC protection current; and

d) Connection or disconnection of instrumentsemployed for measuring and test ing ofcathodic protection system .

11.4.1 In locationswheruny o(thc abovehazards mayarise, the operating pcnonnel should be given suitableimtructiom andwarning notices should be displayed.

11....J II should be noted that likelihood of sparking11 greater with impressed current system than with~rilic••1anode system,

12.-4." R~"'e"IeJ

As cathodic protection ncces.sit&les theusc of electricalequipment. the following safety precautionsshould belaken in hll.lllldous areas:

a) Provide flameproofenclosure of all electricalequipment. such as junction boxes and lest

stations in ICcordance with relennt standards.:rovide continuous bondingcablesacT05S anyintended break. before il is made, inprotcctedpipeline/'tructure.

b) Installation or insulating joints. as far aspossible , in safe anas.

c) Jump over the imulated flanges with a Surgediverter, which gives electrical/metalliccontinuity for high voltages but is highenough to prevent cathodic protectioncurrenu from passing over.

IJ DOCUMENTATION

1J.1 [)alp Doc••ntatiott

13,1.1 G~lWra/

The basic dcsttpl documentation shall include:

a) Results of any site surveys and soilin..-est igatioes th.u have been carried out;

b) Results ofany Cutmll drainage tests that havebeen carried out fOf the retrofitting of CP oecldstini pipeline/structure ;

20

c) Any requirements for modifications withrespect to existing pipeline/structure systemssuch as minimum electrical separation orcoating repairs;

d) Calculations of current requirements.potentialattenuation. electrical resistance andcurrent output of ground beds;

e) Description of system including a schematicdiagram of the proposed CP system ;

f) A list of the estimated number and teststations;

g) Anysensitivitiesin the CP system that requirespecial attention;

h) A schedule of materials;

j) A set of design drawings; and

k) A set of installation procedures.

13.1.2 Construction Details and InstallationProcedures

Full construction details and installation proceduresof the CP system should be documented to ensure thatthe system will be installed in accordance with thisstandard.

These should include:

a) Proceduresfor the installation ofd.c . voltagesources, ground beds, cables, test facilities,cable connections to the pipeline/structure;

b) Procedures for all tests required todemonstratethatthe quality ofthe installationmeets the requirements;

c) ~o~struction drawings including but notlimitedto plot plans, locations ofCP systemsand test facilities, cable routing, single-lineschematics,wiring diagrams and ground bedconstructionand civil works ; and

d) Pr~edures to ensure safe systems of workdunng the installation and operation of theCP system.

13.2 Commissioning Documentation

After the s~ccessful commissioning of the CP system,the follOWing shall be compiled in a commissioningreport

a) As-built layout drawings of the pipeline/structure including neighbouring pipeline!structure or systems that are relevant to theeffective CP of the pipeline/structure,

b) As-built drawings, reports and other detailspertaining to the CP ofthe pipeline/structure,

c) Rec~rds of the interference tests (if any)catrled out on neighbouring pipeline/structure,

d) The voltage and current at which CP s~ stem"as initially set and the \ oltage and currentlevel s necessitated by the results of (heinterference tests . The location and type ofinterference-current sources (if an~ l, and

e) Records of the pipe-to-soil potentials at alltest stations before and after the applicat ionofCP.

13.3 Inspection and Monitoring Documentation

The results of all inspection and monitoring checksshall be recorded and evaluated . They shall be retarned

for use as a baseline for future verifications of CI'effectiveness,

13.4 Operating and Mainten.nct' Documentation

An operating and maintenance manual shall heprepared to ensure that the CP s~ stem is "elldocumented and that operating and maintenanceprocedures are available for operators This documentshall consist of:

a) A description of the s) stem and systemcomponents.

b) Commissioning report.

c) As-built drawings.

21

IS~l: 2006

d I M,muf:tcturer' s documeruauon,

e) A schedule 01 all monuor rng lau lltlClo.

n Potenual crnens fur the s ~ stcm .

g) Monltonng plan.

h) MOnltonn~ schedules :lnd requrrementv !lwtest stations.

J) Monttorlllg procedures Ior each of the tyfX"sof monitoring factllllCs Insl;t llcd nil thepipeline 'structure. and

k) (;uld('lIne\ lor the \ale operanon "I the (,Jls~ stem

13.~ M.inlrnanct' Records

l or marntenance of the C I' I"ellilles. the fnll o" In':rnformauon shall be recorded .

al Repair of rccuficrs and nlher 1.1 ( po"ersources:

b] Repair or replacement 01 an odes. (onne(llo",and cab les,

c) Mamtenance , repair and replacement "Icoating. I\olatinl? devices. le\1 leads and olhe!

lest faclhlJcs ~ and

d ) Dra inage st at ron s. cU1nlt and remotemonuor ing equipment

IS 8062 : 2006

ANNEXA

(Foreword)

COMMITTEE COMPOSITION

Corrosion Protection and Finishes Sectional Committee, MTD 24

Organization

Central Electrochemical Research Institute, Karaikudi

Atotech, Gurgaon

Bhabha Atomic Research Centre, Mumbai

Bharat Electronics Ltd, Ghaziabad/Bangalore

Bharat Heavy Electricals Ltd, Hardwar/Tarnil NadulBhopal

Central Building Research Institute: Roorkee '

Central Electrochemical Research Institute, Karaikudi

Corpotex India Ltd, West Bengal

Department of Road Transport and Highways, New Delhi'

Engineers India Ltd, New Delhi

Fertilizer Plant, SAIL, Rourkela

FGP Ltd, Mumbai

Grauer and Weil (India) Ltd, Mumbai, ,

Gujarat Electricity Board, VadodaralDistrict Khera

HMT Ltd, Bangalore

Indian Explosives Department, District Hooghly

Indian Lead Zinc Development Association, New Delhi

Indian Oil Corporation Ltd, Faridabad

Indian Telephone Industries Ltd, Bangalore

Kalpatru Power Transmission Limited, Gandhinagar

Kongavi Electronics Pvt Ltd, Bangalore

Lloyd Insulations (India) Ltd, New Delhi

L1yods Tar Products Ltd, MumbaiIKolkata

MECON Ltd, Ranchi

22

Representativets)

PROF A. K. SHUKLA (Chairman)

SHRI ADITYA KUMAR JOSHISHRI SANAL KUMAR (Alternate)

DR P. K. DE (METALLURGY DIVISION)SHRI V. K. JAIN (Alternate)

DR M. K. TOTALANI (MATERIAL PROCESSING DIVISION)SHRI A. K. GROVER (Alternate)

SHRI R. C. SETHISHRI N. RAVIBHUSHAN (Alternate)

SHRI D. K. SINGH (Hardwar). SHRI R. M. SINGHAL (Alternate)

SHRI R. RANGANATHAN (Tamil Nadu)SHRI RAJ KUMAR (Bhopal)

DR L. K. AGGARWALDR K. K. ASTHANA (Alternate)

DR N. PALANASWAMY

SHRI S. K. ADlDKARIDR M. SEN (Alternate)

SHRI T. V. BANERJEESHRI S. K. KUSHVAHA (Alternate)

DR G. SAHASHRI G. V. SWAMY (Alternate)

SHRI S. C. DASSHRI M. N. Roy (Alternate)

DR'K. V. RAoSHRI P. GOPALAKRISHNA (Alternate)

SHRI V. S. KULKARNI

SHRI J. N. PATELSHRI R. R. VISHWAKARMA (Alternate)

SHRIMATI NIRMALA NAIKSHRI S. V. S. PRASAD (Alternate)

SHRI SANDIP KUMAR Roy

SmU L. PuGAZHENTHYSHRI T. THANGARAI (Alternate)

SHRI SATISH MAKHIIA

SHRI B. SUBBA RAoSHRI R. RAMEsH (Alternate)

SHRI M. C. MEHTA

SHRI S. KONGAVIDR B. S. SURESH (Alternate)

SHRI K. K. MITRASHRI A. K. RASTOGI (Alternate)

SHRI M. S. THUMPYSHRI U. Roy (Alternate)

SHRI B. N: MUKHOPADHAYAYA

Organization

Metallizing Equipment Co Pvt Ltd, Jodhpur

Ministry of Defence, DGQA, Ambamath

Ministry of Railways, RDSO, Lucknow

National Aerospace Laboratory, Bangalore

National Metallurgical Lab, Jamshedpur

National Test House (ER), Kolkata

Oil and Natural Gas Commission, Dehra Dun

Oil and Natural Gas Commission, Maharashtra

Oil India Ltd, Guwahati

Projects & Development India Ltd (Chemical), Sindri

Pyrene Rai Metal Treatments Ltd, Mumbai

Shipping Corporation of India Ltd, Mumbai

Steel Authority of India Ltd, Ranchi

Steel Authority of India Ltd, Bhilai

Surface Chern Finishes, Bangalore

Tata Motors Limited, Jamshedpur/Pune

Tata Consulting Engineers, Mumbai

TATA SSL Ltd, Mumbai

The Tata Iron & Steel Co Ltd, Jamshedpur

Titan Industries Ltd, Hosur

Vijay Metal Finishers, Bangalore

Zenith Limited, Raigarh

BIS Directorate General

IS 8062 : 2006

Representative(s)

SHRI S. C. MODISHRI R. GIRISH RAo (Alternate)

SQAO, QAE (MET)AQAO, QAE (MET) (Alternale)

ADDITIONAL EXECUTIVE DIRECTOR (M&C)DEPUTY DIRECTOR (CHEMICAL) (Alternate)

DR (SHRIMATI) INDIRA RAJGOPALDR P. K. PARODA (Alternate)

DR T. B. SINGHDR A. K. BHATTAMISHRA (Alternate)

DR SUNIL KR. SAHASHRI SHER SINGH (Alternate)

SHRI V. K. JAIN

SHRI P. F. ANTO

SHRI P. P. BOHA

DR K. N. VERMA

SHRI A. T. PATILSHRI H. C. PAPAIYA (Alternate)

SHRI A. K. SENSHRI N. G. SESAI (Alternate)

DR AMITDAV BHATTACHARYA

DR R. HALDHARSHRI D. DASGUPTA (Alternate)

SHRI P. PARTHASARATHY

SHRI S. S. JUNG BAHADURSHRI R. B. LAHOTI (STANDARDIZATION ERC, PUNE)

SHRI A. MAJUMDAR (Alternate)

SHRI VINAY V. PARANJAPESHRI PARAG P. JOSHI (Alternate)

SHRI V. C. TRICKURSHRI S. V. DESAI (Alternate)

DR S. K. SENSHRI R. N. CHATTOPADHYAYA (Alternate)

SHRI P. ASHOK ANURSHRI C. V. S. PRASAD (Alternate)

DR H. B. RUDRESH

SHRI ARUN MEHTA

SHRI S. K. GUPTA, Scientist ' F' and Head (MTD)[Representing Director General (Ex-offiCio)]

Member SecretarySHRI 1. K. BAKHROO

Scientist 'E' Director (MTD), BIS

Panel on Cathodic Protection of Pipe Line, MTD 24/P-I

GAIL ·India Ltd, New Delhi

Bharat Petroleum Corporation Ltd, Noida

Corrosion Control System, Mumbai

Corrosion Consultant, Noida

23

SHRI NARENDER KUMAR (Convener)SHRI PARTHA JANA (Alternate)

SHRI UMESH GAUTAM

SHRI V. G. KULKARNISHiu ANAND KULKARNI (Alternate)

DR M. B. MISHRA

IS 8062 : 2006

Organization

Engineers India Ltd (Ell) , New Delhi

Gujaral Gas Company Ltd. Surat

Indian Oil Corporation Ltd (JOCl). NoidalB ijwasan

Oil Ind ia ltd. Noida

Oil & Natural Gas Commission (ONGe). New Delhi

Relian ce Industries ltd. Navi Mumbai

SSS Electricals (India) Ltd, Mumbai

24

Representativets}

SHRI S . K. GUPTA

SHRI DEEPAK DilARMARHA (AI/ema/e)

SHRI SADHAN BANERJEE

SHRI RA1ENDRA KUMAR

SHRI S . B. CHATrnUEE (Alterna/e)

SHRI I. BHARAU

SHRI P: JAMAL (Alternate)

REpRESENTATIVE

SHRI SANDEEP VYAS

SHRI M. N. BHAGAVAN (AI/ema/e)

SHRI R. P. NAGAR

SHRI K. S. SHASIDDHAR (Alternate)

Bureau of Indian Standards

BIS is a statutory institution established under the Bureau of Indian Standards Act, 1986 to promoteharmonious development of the activities of standardization, marking and quality certification of goods andattending to connected matters in the country.

Copyright

BIS has the copyright of all its publications. No part of these publications may be reproduced in any formwithout the prior permission in writing of BIS. This does not preclude the free use, in the course of implementingthe standard, of necessary details, such as symbols and sizes, type or grade designations. Enquiries relating tocopyright be addressed to the Director (Publications), BIS.

Review of Indian Standards

Amendments are issued to standards as the need arises on the basis of comments. Standards are also reviewedperiodically; a standard along with amendments is reaffirmed when such review indicates that no changes areneeded; if the review indicates that changes are needed, it is taken up for revision. Users of Indian Standardsshould ascertain that they are in possession of the latest amendments or edition by referring to the latest issue of'BIS Catalogue' and 'Standards: Monthly Additions'.

This Indian Standard has been developed from Doc: No. MTD 24 (4675).

Amendments Issued Since Publication

Amend No. Date of Issue

BUREAU OF INDIAN STANDARDS

Text Affected

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