STOD-ECM-TPL-0806-QC-MST-0003 (B01) Work method statement for cathodic protection (2).docx

7/25/2019 STOD-ECM-TPL-0806-QC-MST-0003 (B01) Work method statement for cathodic protection (2).docx

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Work method statement for cathodicprotection

STOD-ECM-TPL-0806-QC-MST-000

Project Title : EPCC ! Tr"nk Line and Waha #eception $aci%itiesContract No : OM&'ECM(-OTP'PP')**ECM Job No : )*+00),

Prepared by :

ECM(EPC ContractorFax : (+216) 1 !6" #$Tel : (+216) 1 !6" 6"Project %eb &ite: %%%'&tod'tn

REVISION RECORD

REV Status Date Description Prepd Checkd Apprvd OMV

B01 IFR 110!

"01!

Issued $or Revie% IARD FSAI &'(I

This document is the property of OMV & ETAP. It shall not be copied, reproduced and circulated without the Authoriation of OMV & ETAP.

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http://www.stod.tn/http://www.stod.tn/


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.OTES/

(i) -e.i&ion and &tat/& i& a& 0ollo%&:

-e.i&ion tat/& *e&cription *M er&ion

3 *-3 *ra0t $

4 5F- 5&&/ed 0or -e.ie% 1

C 5F3 5&&/ed 0or 3ppro.al 2

$ 5F 5&&/ed 0or &e

(ii) -e.i&ion n/ber& are 37 47 C7 etc' 0or *-37 5F- and 5F37 i0

appropriate7 /p /ntil 5&&/e 0or Con&tr/ction (5F*)7 %8ic8 &8all be

-e. $' /b&e9/ent re.i&ion& are 17 27 etc'


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T1LE O$ CO.TE.T

*23.T#OD4CT3O.22222222222222222222222222222222222222222222222222222222222222222222222222+

1'1 P-JECT P-EENT3T5N'''''''''''''''''''''''''''''''''''''''''''''''''''''''';

1'2 CPE'''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''"

1' -EFE-ENCE C*E'''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''"

1'; TE-M 3N* *EF5N5T5N''''''''''''''''''''''''''''''''''''''''''''''''''''''"

) 5E.E#L2222222222222222222222222222222222222222222222222222222222222222222222222222222222222

2'1 P5PE


4/17

*2 3.T#OD4CT3O.

*2* Proect PresentationEPCC F Tr/nB line ("$B #) and a&&ociated reception 0acilitie& and tie

in& at Da8a CPF in t8e 3E* de.elopent copri&in,:

3 /ltip8a&e pipeline 0ro 3na,/id =at8erin, Point (3=P) to t8e

exi&tin, D3>3 CPF incl/din, pi, la/nc8in, and recei.in, 0acilitie&7

$2


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*2) Scope

cope o0 t8i& &t/dy i& t8e de&i,n o0 a Cat8odic Protection y&te nece&&ary to

&a0e,/ard a,ain&t electroc8eical corro&ion o0 external &/r0ace& o0 b/riedpipeline& # WAHA-ANAGUID.

*2 #eference codes

N3CE -P$16!Control o0 External Corro&ion on nder,ro/nd

or /ber,ed Metallic Pipin, y&te&'' 3-MA C-P F

EN=5NEE- FC "$$6

Cat8odic Protection y&te& peration 3nd

Maintenance'' 3-MA C-P F

EN=5NEE- FC "$

$2N

*e&i,n: Electrical En,ineerin, Cat8odic

Protection

'' 3-MA C-P F

EN=5NEE- FC "$

$23

Cat8odic Protection

T "1;1 EN 12!";Cat8odic Protection Principle& 0or b/ried

pipeline&T!2; Cat8odic Protection =al.anic 3node&

*2+ Terms and Definitions

node/ 1: T8e electrode o0 an electroc8eical cell at %8ic8 oxidation occ/r&

(electron& 0lo% a%ay 0ro t8e anode7 con.entional c/rrent to%ard t8e anode int8e norally etallic external circ/itG t8e anode i& /&/ally t8e electrode %8ere

corro&ion occ/r& and etal ion& enter &ol/tion) 2: 5n cat8odic protection7 an

electrode t8at di&c8ar,e& c/rrent to t8e electrolyte7 %8ere it 0lo%& to t8e

cat8odically protected &/r0ace'

node ca9%e: In an ipre&&edc/rrent cat8odicprotection &y&te7 t8e cable0ro t8e po&iti.e terinal o0 t8e *C po%er &o/rce to t8e ,ro/nd bed'

1ackfi%%/


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Coatin:: 3 dielectric aterial applied to a &tr/ct/re to &eparate it 0ro t8een.ironent'

Corrosion/ T8e deterioration o0 a aterial7 /&/ally a etal7 by reaction %it8 it&en.ironent'

Criterion: tandard 0or a&&e&&ent o0 t8e e00ecti.ene&& o0 a cat8odic protection&y&te'

C"rrent: 5n t8i& an/al c/rrent ean& con.entional c/rrent7 i'e'7 t8e re.er&e o0electron 0lo%' Electron& 0lo% a%ay 0ro t8e anode7 con.entional c/rrent 0lo%&

to%ard t8e anode in t8e norally etallic external circ/it' T8e anode i& /&/ally

t8e electrode %8ere corro&ion occ/r& and etal ion& enter &ol/tion'

C"rrent densit;: T8e c/rrent per /nit area'

Drain point: T8e point on a cat8odically protected &tr/ct/re %8ere t8e draincable i& connected'

E%ectrode/ 3n electronic cond/ctor /&ed to e&tabli&8 electrical contact %it8 anelectrolyte part o0 a circ/it'

E%ectro%;te: 3 c8eical &/b&tance or ixt/re containin, ion& t8at i,rate in anelectric 0ieldG in t8i& an/al7 t8e &oil or li9/id7 incl/din, t8e oi&t/re and ot8er

c8eical contained t8erein7 adjacent to and in contact %it8 a b/ried or

&/ber,ed etallic &tr/ct/re'

$orei:n str"ct"re/ any &tr/ct/re t8at i& not intended a& a part o0 t8e &y&te tobe protected'

5a%


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#eference e%ectrode: 3 re.er&ible electrode %it8 a potential t8at ay becon&idered con&tant /nder &iilar condition& o0 ea&/reent (exaple&:

&at/rated coppercopper &/l0ate7 &at/rated caloel7 and &il.er&il.er c8loride)'

#esisti


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+ #ES3ST3&3T

T8e &oil& are cla&&i0ied in FC Cat8odic Protection (FC "$$23) a& per t8eir

corro&i.ity %it8 re&pect to t8eir electrical re&i&ti.itie&' T8e ea&/red .al/e&d/rin, t8e &ite &/r.ey %ill be e.al/ated in accordance %it8 t8e Table1 belo%:

Table 2: Corro&i.ity o0 &oil& on &teel ba&ed on &oil re&i&ti.itySoi% #esisti cm? Corrosii,8 corro&i.e)2$$$ to 1$$$$ Moderate to &e.ere (Corro&i.e)1$$$$ to $$$$ Mild (


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t8e &tr/ct/re i& in&talled' T8e c/rrent den&itie& re9/ired 0or cat8odic protection

depend on t8e etal bein, protected and t8e en.ironent'

Typical .al/e& 0or t8e c/rrent den&itie& re9/ired 0or cat8odic protection o0 bare&teel &tr/ct/re& are &8o%n in Table 2' Typical .al/e& o0 t8e c/rrent den&itie&

re9/ired 0or cat8odic protection o0 coated &teel &tr/ct/re& are &8o%n in Table ;

(FC peration and Maintenance: Cat8odic Protection y&te&7 FC "$$6)'

Table : C/rrent -e9/ireent& 0or Cat8odic Protection o0 4are teel

E.&3#O.ME.TM3LL3MPE#ES

PE# SQ4#EMETE#

PE# SQ4#E$OOT

oil %it8 re&i&ti.ity I$7$$$ o8c 1$' 21'" 1 2oil %it8 re&i&ti.ity 1$7$$$ $7$$$ o8c 21'" 2' 2

oil %it8 re&i&ti.ity 17$$$ and 1$7$$$ o8c

;'$ 6;'6 ; 6

oil %it8 re&i&ti.ity K17$$$ o8c "' 26!'1 2">i,8ly a,,re&&i.e &oil %it8 anaerobic bacteria 161'" ;$'" 1" ;$till 0re&8 %ater 21'" ;'$ 2 ;Mo.in, 0re&8 %ater ;'$ 6;'6 ; 6T/rb/lent 0re&8 %ater "'# 161'; " 1">ot 0re&8 %ater "'# 161'; " 1"till &ea%ater 1$' 2' 1 Mo.in, &ea%ater 2' 26!'1 2"Concrete "'; 16'1 $'" 1'"

Table ;: C/rrent -e9/ireent& 0or Cat8odic Protection o0 Coated teel

ST#4CT4#EM3LL3MPE#ES

PE# SQ4#EMETE# =$OOT?

COT3.5E$$3C3E.C

Pipeline7 epoxy or ot8er 8i,8 per0orance coatin, $'$1$$'$";($'$$1$'$$") !!'" !!'!Pipeline7 rein0orced coal tar or a&p8alt enael $'$";$'26!($'$$"$'$2") !'" !!'"Pipeline7 ,rea&e coatin, %it8 %rapper $'"#1'61"($'$"$'1") #"'$ !"'$

Pipeline7 a&p8alt a&tic L t8icB $'$$1$'$$"($'$$1

$'$$")

!!'" !!'!

Pipeline7 old a&p8alt or ot8er deteriorated coatin, $'"#'6($'$"$'") 6"'$ !"'$

Pipeline7 old paint coatin, 1'$6$'"22($'1$$'$) $'$ !$'$TanB botto& $'"#21'"2!($'$"2'$$) ' !#'TanB& 0or cold potable %ater $'"#21'"2!($'$"2'$$) ' !#'TanB& 0or cold &ea %ater $'"#;'$"6($'$";'$$) 2$'$ !!'$>ot potable %ater tanB& $'"222'2!2($'$'$$) ;$'$ !;'$teel &8eet pilin, 0re&8 %ater &ide 1'$616'1;6($'1$1'"$) $'$ !#'$teel &8eet pilin, &ea %ater &ide 1'$621'"2!($'1$2'$$) 6$'$ !#'$teel &8eet pilin, &oil &ide $'21";'$;($'$$2$';$) #$'$ !!'$

TaBin, into acco/nt t8e abo.e &tateent& 0or t8e c/rrent need& o0 t8e pipeline a&

5 $'2 32i& taBen into acco/nt'


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,2* Str"ct"res to 9e Protected

5n order to e&tiate total protecti.e c/rrent re9/ireent&7 External &/r0ace area

o0 b/ried &teel pipeline 8a& been deterined' /r0ace area o0 t8e one b/ried&teel pipeline'

External &/r0ace area o0 t8e b/ried &teel pipe line 8a& been calc/lated by /&in,

t8e ,i.en 0or/la& belo% a& an exaple'

A= x Dexx L

D8ere 3i& total &/r0ace area o0 b/ried &teel pipeline7 *exi& external diaeter and

< i& t8e total 3 CPF)

!) T8e anode ,ro/ndbed /&t be 0ar a%ay 0ro t8e ot8er etallic

/nder,ro/nd &tr/ct/re& to pre.ent t8e inter0erence'

1$) T8e anode ,ro/ndbed %ill be e&tabli&8ed a& 8oriHontal anode

,ro/ndbed'


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62) C"rrent #eA"irement of Cathodic Protection

T8e c/rrent re9/ireent o0 t8e pipeline i& calc/lated in accordance to t8e &peci0ic

&oil re&i&ti.ity o0 t8e location %8ere t8e polyet8ylene coated line lie&7 dependin,on t8e potential c8an,e o0 c/rrent draina,e point a& &tip/lated in t8e ter& o0

re0erence'

A= 34,454.592 m2

I= 0,2 mA/m2

Ip= A.I

= 34454.592 m2x 0.2 mA/m2

= 6890.92 mA.= 12/3.

62 Desi:n of node 5ro"nd9ed of Cathodic Protection Stations

6''1 E&tabli&8ent o0 3node =ro/ndbed % Fer&ili&y/ 3node&

5n t8e &cope o0 t8i& project7 t8e anode ,ro/ndbed& %ill be e&tabli&8ed by

Fer&ili&y/ t/be anode&7 %8ic8 are %idely /&ed in recent year& a& tec8nolo,ical

prod/ct' T8e calc/lation& 0or t8e e&tabli&8ent o0 anode ,ro/ndbed are

pre&ented in t8i& &ection'

T8e Fer&ili&y/ t/be anode& %it8 "$ diaeter71"$$ len,t8 and 2$ B,

%ei,8t %ill be /tiliHed in t8i& application'

3node ,ro/nd bed = x D x L = 3.14 x 50 x 1500 = 235500mm 2

= 0,2355 m2

50 1$32c/rrent can be taBen 0ro one anode 0or 2$ year&7 t8e axi/

c/rrent 0ro one anode 0or "$ year& i& calc/lated a& 0ollo%&:

i 1$ x $72"" 272 3T8e anode ,ro/ndbed& are t8e one o0 t8e o&t &i,ni0icant ite& o0 t8e cat8odic

protection &tation&' T8ey are e&tabli&8ed by t8e parallel connection o0 ade9/ate

ao/nt o0 Fer&ili&y/ t/be anode& 8a.in, t8e c8aracteri&tic& p/r&/ant to t8e

ter& o0 re0erence' T8e ini/ n/ber o0 anode& in one anode ,ro/ndbed&8o/ld be a n/ber t8at %o/ld pro.ide t8e re9/ired c/rrent o/tlet 0or t8e

protection o0 t8e &y&te 0or a li0e&pan claied in t8e ter& o0 re0erence'


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T8e anode ,ro/ndbed& are e&tabli&8ed by t8e parallel connection o0 anode& o0

ade9/ate n/ber t8at pro.ide& t%o ba&ic eleent& explained abo.e'

3ccordin,ly:Table ": *e&i,n C/rrent Capacity o0 3node =ro/ndbedand Mini/ -e9/ired 3node 3o/nt

CPS.o

Ca%c"%ated C"rrentCapacit; =?

Desi:n C"rrent Capacit; ofnode 5ro"nd9edB => *2*,?

Minim"mnode

."m9er =n?CP1 6'#!1 '!2" *

6''2 3node =ro/ndbed& E&tabli&8ed at Cat8odic Protection tation& and T8eir

-e&i&ti.ity

3ccordin, to t8e ter& o0 re0erence7 total re&i&ti.ity at t8e circ/it o0 t8e cat8odicprotection /&t be le&& t8an 2 8'

Circ/it re&i&ti.ity o0 cat8odic protection &y&te T- nit 5nternal -e&i&ti.ity

(,enerally ne,lected) + Ne,ati.e line cable re&i&ti.ity + Po&iti.e line cable

re&i&ti.ity + 3node& ,ro/ndbed re&i&ti.ity + Pipe &oil tran&ition re&i&ti.ity'

3node ,ro/ndbed can be 0ored by ade9/ate n/ber o0 Fer&ili&y/ t/be anode&

connected in parallel' 3node& are 1'6 deep and 8oriHontally placed and t8e

di&tance bet%een anode& i& " at t8e anode ,ro/ndbed' Typical anode

,ro/ndbed layo/t plan i& ,i.en in Fi,/re 1'


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Anode Lead Cable

Groundbed cables


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4

0

1

0

0

1

8

0

3 0

4 0

A - A S e c t i o n

Fi,/re 1 3node =ro/ndbed Plan

Table 6: T/b/lar 3node *ien&ion&

Diameter Len:th Wei:ht

"$1"$$

2$ B,

T8e n/ber o0 t8e anode to be /&ed at t8e anode ,ro/ndbed %ill be 2$ anode&

and t8e anode ,ro/nd bed %ill be e&tabli&8ed at lea&t !1 (/&/ally !1 to 21

eter& $$ to $$ 0eet7 FC peration and Maintenance: Cat8odic Protection

y&te&7 FC "$$6) 0ar 0ro t8e anode ,ro/ndbed'

6'' 3o/nt o0 4acB0ill Material (coBe breeHe) o0 3node =ro/ndbed

To red/ce t8e re&i&ti.ity o0 a&&i&tant anode and to pre.ent t8e polariHation7 t8e

coBe breeHe i& /&ed a& bacB0ill aterial o0 anode ,ro/ndbed'

T8e bi,,e&t diaeter o0 coBe breeHe /&t be 1$ and pa&&in, part o0 coBe

breeHe 0or n/ber 1$$ &ie.e /&t be "'

6.3.3.1 Lifespan of Anode Groundbed

Control o0 N/ber o0 3node&:

Cat8odic protection &y&te i& de&i,ned 0or at lea&t "$ year&' T8ere0ore7 t8e

ao/nt o0 anode& /&t pro.ide t8e li0e&pan entioned abo.e :

N/ber o0 anode& /&ed in cat8odic protection &tation7 n 2$ /nit

C/rrent o/tlet 0ro cat8odic protection &tation75 6'#!1 3 Maxi/ dra%n c/rrent 0ro one anode7 5one 2' 3

Maxi/ dra%n c/rrent 0ro 2$ anode7 5one 2$ x 2' ;6 3 I "7" 3

(eno/,8 anode n/ber)


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R1 : T/R Unit internal resistivityR2 : Resistivity of anode groundbed R3 : Cable resistivity on the syste

R! : "i#e$soil transition resistivity%

Characteristic resistivity

R1

R2

R3

R!

R

6.3.3.2 Circuit Resistivity of Cathodic Protection and

Transformer Rectifier !nit

T8e .olta,e capacity o0 T- /nit to be /&ed in cat8odic protection &y&te %it8exterior c/rrent &o/rce depend& on t8e de&i,n c/rrent re9/ireent and total

circ/it re&i&ti.ity at t8e circ/it o0 cat8odic protection'

!/"= IDSI#$ x "!

3ccordin, to t8e ter& o0 re0erence7 t8e c/rrent capacity o0 T- nit i&

con&idered to be 2"ore o0 t8e protection c/rrent re9/ireent' T8e calc/lated

de&i,n c/rrent capacity o0 T- nit to be in&talled at t8e cat8odic protection

&tation i& ,i.en in Table!'

Table : *e&i,n C/rrent Capacity o0 T- nit to be in&talled 0or Protection o0 Pipeline

CPS.o

C"rrent Capacit; of T'# nitB=a?Ca%c"%ated C"rrent

#eA"irementDesi:n> *2*,

CP1 6'#!1 '!2"

T8e re&i&ti.itie& in t8e cat8odic protection circ/it %it8 a exterior c/rrent &o/rce

are &8o%n in 0i,/re 2'

Fi,/re 2: -e&i&ti.itie& on Cat8odic Protection Circ/it

5t i& t8e addition o0 re&i&ti.itie& o0 t8e cable& o0 t8e po&iti.e line layin, 0ro T-

/nit to t8e anode ,ro/ndbed and t8e ne,ati.e line layin, to%ard& t8e pipe' T8e&e

cable& are in&talled a& 1x2"2 and 1x16 2'

Cable -e&i&ti.ity s

LR =

4y t8e /&e t8e 0ollo%in, t8ree .al/e& and t8e len,t8& < ,i.en in t8e 0i,/re abo.e7

r $'$1#8'27 &peci0ic re&i&ti.ity o0 cable

& 2"2 7 Cro&&&ection o0 cable

L = Len%t& o' c()*e

.OTE/-@ $7;$"2 8 (T8e arit8etic a.era,e diaeter o0 all -@)olta,e Capacity o0 T- nit:

ET- 5*E5=Nx -T


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5*E5=N '!2"3

-T 1'"!2 8

ET- 67!6 x 1'"!2

12762 olt

3.STLLT3O. O$ CT7OD3C P#OTECT3O.

2* Cathodic protection station

Cat8odic protection &tation in accordance %it8 appro.ed project& %ill be

e&tabli&8ed' Tran&0orer-ecti0ier /nit 0or 22$ or #$ ac &/pply line& %ill be

done %it8 2x6 2 NA-A cable' Feed line in place t8e 6$ PC or

,al.aniHed pipe %ill be in con&er.ation' T - /nit nece&&ary %it8 2" O cable

and copper ,ro/ndin, bar %it8 dien&ion& 2$x1"$$ 8o/&in, " o8 eart8&tation &y&te& to be inte,rated into t8e &oil %ill be' Protection o0 cable& laid

Cat8odic &tation7 i& &8o%n in t8e project %ill be branded %it8 t8e cable carryin,

&i,nal'

2) node 1ackfi%%

peci0ication:

Fixed carbon !!3&8 $'1olatile& $'2

/lp8/r $';" *en&ity 2'1-e&i&ti.ity """o8'cSpecial bacB0ill can be &/pplied /pon receipt re9/e&t'

NTE: T8e c8eical copo&ition li&ted i& 0or exaple only' T8e act/al type and

copo&ition re9/ired &8all be deterined by t8e de&i,n en,ineer to pro.ide

ade9/ate and econoical &er.ice'

2 Spark 5aps

T8e pipeline %ill be &eparated 0ro t8e exi&tin, /nder,ro/nd etallic &tr/ct/re&

.ia 0abricated i&olated co/plin,& at t8e be,innin, o0 t8e pipeline and at t8e endo0 t8e line' T8e &tatic electricity acc//lated on t8e pipeline %ill be reo.ed by

t8e &/r,e di.erter&'

2+ 5ro"ndin: S;stem

T8e T- /nit& %ill be ,ro/nded &eparately 0ro t8e exi&tin, ,ro/ndin, &y&te

%8ere t8e T- /nit %ill be pre&ent' T8e ,ro/ndin, &y&te %ill be e&tabli&8ed

%it8o/t exceedin, t8e total re&i&ti.ity o0 " 8'


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2, Test Stations

3ll te&t &tation& %ill be o0 t/b/lar type' T8e te&t &tation& %ill be 8ot ,al.aniHed

and t8e ,al.aniHed linin, %ill be painted %it8 %8ite colo/r& epoxy paint'cable 1 x 16 2type 1$$$ - 2 re&i&tant &oil a,,re&&i.ene&& i& attac8ed to

t8e pipe by t8erite %eldin, Cad%eld type'

T8e cable& /&ed 0or di00erent potential type %ill be taBen 1$$$ - $2 and &8all

8a.e t8e 0ollo%in, color code:

3node: -ed

Cat8ode: 4lacB

T8ird tr/ct/re: =rey

Eart8: Aello% =reen

Metal &8eat8: Aello%

5n&/latin, Joint: 4l/e

STOD-ECM-TPL-0806-QC-MST-0003 (B01) Work method statement for cathodic protection (2).docx

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