Post on 31-Dec-2015
description
Pipeline Integrity Assessment
?
?
GNP 4% GNP 4%
(1999) 1/3
(1999) 1/3
Summary of Incident CausesSummary of Incident Causes
ASME Causes of Gas Transmission Incidents
External Corrosion
Third Party Damage
I t O ti
Misc
Natural Forces
Internal Corrosion
Constr/Instal
Other Failures
Unknown
Incorrect Operation
Non-PipePipe
Malfunction
Prev. Damgd Pipe
Mfr
Constr/Instal Pipe
0.0 2.0 4.0 6.0 8.0 10.0 12.0 14.0
Vandalism
Stress Corrosion Cracking
Avg Annl Incidents, 85-01
COST OF CORROSIONCOST OF CORROSION
$5 0 bil$5.0 bil.
4Department of Transportation (DOT), USA, 2001 ($276 bil.)
Cost Estimate Example Offshore PNG PipelineCost Estimate Example Offshore PNG Pipeline
C (US $ Milli )Category
Cost (US $ Million)
7.4 MPa 8.4 MPa 10 MPa 12 MPa
Bare Pipe Materials 374.1 314.4 296.5 228.8
External Coating 44.1 44.1 44.1 42.0
Internal Coating 21.2 21.3 21.2 21.2
Weight Coating 67 2 63 7 57 8 54 0Weight Coating 67.2 63.7 57.8 54.0
Cathodic Protection 20.7 20.5 20.5 20.2
Pipe Laying 80.7 78.1 80.8 80.8
Dredging& Backfill 17.7 17.1 16.8 16.1
Mobil. & Demobil. 8.4 8.4 8.4 8.4
Total 634 1 567 6 546 1 471 5Total 634.1 567.6 546.1 471.5
10 15% of total direct construction cost for corrosion protection (coating + CP)(Cited from Feasibility Study Report for Irkutsk PNG pipeline)
CASE HISTORIES ON UNDERGROUND CORROSIONCASE HISTORIES ON UNDERGROUND CORROSION
Corrosion on the pipeline
Corrosion on the bottom plates of aboveground storage tank
CORROSION IN ANAEROBIC SOILCORROSION IN ANAEROBIC SOIL
Chemical/microbiological corrosion
/
Electrical corrosion
10
(corrosivity)
, ,
333
vs. vs. P/S Disbonded area Sulfate
2
P
0
2
P
0
2
P
0
0 1 2 3 40
1
0 20 40 60 80 100 1200
1
2 0 1 8 1 6 1 4 1 2 1 00
1
3
2
100 101 102 103 104
[SO42-] (mg/g of soil)
0 20 40 60 80 100 120
Disbonded Area (cm2)
-2.0 -1.8 -1.6 -1.4 -1.2 -1.0
P/S (V/CSE)
pH SRB
2
Resistivity
2
P
0
1
P
0
1
P
0
0
1
4 5 6 7 8 9 100
0
1
103 104 105 106 107 108 109
SRB (cells/g of soil)
4 5 6 7 8 9 10
pH101 102 103 104
0
Resistivity (Ohm.cm)
Soil Resistivity Soil Resistivity Wenner 4-Pin Resistivity Measurement
I
E
SSS
. = RA/L (cm) ()
4-pin method
Soil box
SOIL RESISTIVITY SURVEY: EQUIPMENTSSOIL RESISTIVITY SURVEY: EQUIPMENTS
Soil pin
. .
a/2 .
5 000 ohm cm 5,000 ohm.cm
() ()1.E+06
1 E+051.E+05
t
y
(
.
c
m
)
1.E+04
S
o
i
l
R
e
s
i
s
t
i
v
i
t
1.E+03
S
corrosive
1.E+020 10 20 30 40 50 60 70 80 90 100 110 120 130
Distance (km)
AA
A B ?
B
19
A, B ?
SOIL RESISTIVITY SURVEY: DEPENDENCY ON SOIL DEPTH: DEPENDENCY ON SOIL DEPTH
A. . B. . . C. .D.
20
SOIL RESISTIVITY SURVEY: BARNES METHOD: BARNES METHOD
T
1h1
2
3
h2
h3 3
4
h3
h4
h
S
1111S
5h5
21n21 RRRR
S
SOIL RESISTIVITY SURVEY: BARNES METHOD: BARNES METHOD
4m 111 42
4224
RRR
RRR
1. 2m, 4m
4242
4242
RRRR400
RRR
1. 2m, 4m (R2, R4)
2. R2-4 42
42 RR
3. 2-4
22
SOIL RESISTIVITY SURVEY: BARNES METHOD: BARNES METHOD
Pin 2m R2 = 6.3 Pin 4m R4 = 1.3
2m 2= 22006.3=7,917 cm 2m 4= 22006.3=3,267 cm
2-4 = 400(R2R4)/(R2-R4)00 ( 3 6 3)/(6 3 3) = 400(1.36.3)/(6.3-1.3)
= 2,061
Test data Barnes AnalysisTest data Barnes Analysisa (cm) R (Ohms) Avg. 1/R (1/R) Layer R Layer
200 6.3 7,917 0.16 - 6.3 7,917
23
400 1.3 3,267 0.77 0.61 1.64 2,061
SOIL RESISTIVITY SURVEY: BARNES METHOD: BARNES METHOD
Test data Barnes AnalysisTest data Barnes Analysisa (cm) R (Ohms) 1/R (1/R) Layer R Layer
150 1.1 0.91 - 1.1 1,040300 0.89 1.1 0.19 5.3 4,995450 0.46 2.2 1.1 0.91 858600 0 14 7 1 4 9 0 20 190600 0.14 7.1 4.9 0.20 190750 0.083 12 4.9 0.20 190900 0.076 13 1.0 1.0 94
Ref.) T.H. Lewis, Jr., Deep Anode Systems, NACE (2000) p.7-11
24
(sulfate- (sulfatereducing bacteria; SRB)
CORROSION IN ANAEROBIC SOILCORROSION IN ANAEROBIC SOIL
SULFATE-REDUCING BACTERIA (SRB)
SO 2 ATP APS PPi
SULFATE-REDUCING BACTERIA (SRB)
SO42- SO42- + ATP APS + PPi Pi
2e-
SO32- + AMP
Enters cell
H+
S2O52- Metabisulfite
2e-
2e- S2-
S2O42- Dithionite
S3O62- Trithionate 2e- S2O32-
Outside cell
2e 2e Thiosulfate
Anaerobic bacteriaNeutral environments
Reducing sulfate to corrosive sulfides
27
SRB Population vs. Soil Key Parameters
107
108
109
p y
Resistivity Redox potential
7
108
109
107
108
109
104
105
106
10
c
e
l
l
s
/
g
-
s
o
i
l
)
105
106
107
e
l
l
s
/
g
o
f
s
o
i
l
)
104
105
106
10
c
e
l
l
s
/
g
-
s
o
i
l
)
101
102
103
S
R
B
(
c
Clay content102
103
104
S
R
B
(
c
e
101
102
103
S
R
B
(
c
108
109
-0.2 0.0 0.2 0.4 0.6 0.8100
Eh (V/NHE)
Clay content102 103 104 105 106
101
( cm)0 10 20 30 40 50 60
100
Clay Content (%)
108
109
106
107
108
/
g
-
s
o
i
l
)
105
106
107
/
g
-
s
o
i
l
)
Anaerobic,Neutral,High clayey,L i ti it
103
104
105
A
P
B
(
c
e
l
l
s
/
102
103
104
S
R
B
(
c
e
l
l
s
/ Low resistivity,High water content
102
10
102 103 104 105 106 107 108 109
SRB (cells/g-soil)
0 10 20 30 40 50100
101
Water Content (%)
Water content APB
C i E Ti
Corrosion vs. Exposure Time
04A
-0.6
-0.4 SRB-active Biocide added APB-active
V
/
S
C
E
)
2
U
n
i
t
)
25m A
C
10
-0.8E
c
o
r
r
(
m
V
0 2 4 6 8 100
1
AlSiFe
O
C
P
SFe
Fe
C
o
u
n
t
s
(
A
r
b
.
U
20m
0.3
0.4-1.0
0.36mm/y
t
e
(
m
m
/
y
)
B D
Energy (keV)
0.1
0.2
o
r
r
o
s
i
o
n
R
a
t
20m
2m
2.0
0 50 100 150 2000.0C
o
Time (Day)1.0
1.5
2.0
O SFe
n
t
s
(
A
r
b
.
U
n
i
t
)
0.5
1.0
1.5
Fe
O
C P
S
Fe
C
o
u
n
t
s
(
A
r
b
.
U
n
i
t
)
0 2 4 6 8 100.0
0.5
Al
SiFe
CP
Fe
C
o
u
n
Energy (keV)
0 2 4 6 8 100.0
Si Fe
Energy (keV)
MIC in Aerobic Condition2.0
MIC in Aerobic Condition
1.0
1.5
O SFe
A
r
b
.
U
n
i
t
)
0 0
0.5
Al
SiFe
CP
Fe
C
o
u
n
t
s
(
A
0 2 4 6 8 100.0
Energy (keV)
SRB
CPCP CPCP SRB-active soil
Ref.) K. Kasahara, et al., Corrosion, 55(1) (1999) 74
The change of local chemistry at metal
OH2He2OH2 22
The change of local chemistry at metal surface, inducing an increase of pH.
Effective tool for prevention of SRB-induced MIC in soil.
31
CP vs MICCP vs. MIC3
2
P
0
1
-2.0 -1.8 -1.6 -1.4 -1.2 -1.00
P/S (V/CSE)P/S (V/CSE)
Despite of coating and CP, MIC occurred. All corrosion occurred the region under the disbonded coating. All corrosion occurred the region under the disbonded coating.
Pt & Reference
~15cm depth
PtRef2PipeRef1
15cm depth
1. Ref 1 vs. Pipe 2. Ref 2 vs. Pipe 3. Ref 2 vs. Pt
33
Potential mV vs. Cu/CuSO4
P/S -1430 (-1200)
I C i 610 ( 500)In Crevice -610 (-500)
Pt Electrode -480Pt Electrode 480
Redox -160 (vs. NHE)*1
*1. At pH 7
34
ANSI/AWWA ANSI/AWWA < 700700 - 10001000 - 12001200 - 15001500 2000
108521
(polyethylene encasement) 1500 - 2000
> 200010
pH0 - 22 - 4
53
encasement)
10
4 - 6.56.5 - 7.57.5 - 8.5> 8.5
00**03
(mV)> 10050 - 1000 - 50< 0
03.545
(sulfide)i i 3
DIN 50929 ,
positivetracenegative
3.520
(moisture)(drainage) ,
21
35
, ,
10
CORROSIVITY MAP ( )CORROSIVITY MAP ( )
36
Corrosion of Steel in Soil EnvironmentCorrosion of Steel in Soil Environment
P=ktn
e
p
t
h
/
m
m
)
x
i
m
u
m
P
i
t
D
e P=ktn Power law P: t:
P
(
M
a
x
k, n:
t, (Time/year)
k n k n . .
37
)(LogpH014.0ClayE050.0)Cl(Log203.0S/P749.0)SRB(Log069.0700.0LogP hc
2.5
R=0.942R=0.942
)(gpy)(g)(gg hc
1 5
2.0 372.0c0 tP500.0P
1.0
1.5
P
0
,
o
b
s
0.5
Chemical factors Biochemical (microbial) factors CP effects
0.0 0.5 1.0 1.5 2.0 2.50.0
38
P0, cal
INTERFERENCEINTERFERENCE
(interference)
(stray current; ) () (: )
(; stray current corrosion)
,
, , AC
(anodic interference) (anodic interference)
, ,
(anodic interference) (anodic interference)
(cathodic interference) (cathodic interference)
+ crossing
3
1
2 Rectifierpower up
V
/
C
S
E
-1
0
Rectifier
i
n
e
P
o
t
e
n
t
i
a
l
,
corrosion !!
-2
P
i
p
e
l
0 50 100 150-3
Distance, m
STS 304L : 1 : 1.2V/CSE
DC
(combined interference) (combined interference)
(combined interference) (combined interference)
49
9 1 9 1
25km, 9 7 2
10km, 3 3k : ~3km
80
90
100
8
9
10
)
feeding current ()
40
50
60
70
80
4
5
6
7
8
e
C
u
r
r
e
n
t
,
I
l
'
'
'
(
A
)
Il '''/I (%
0
10
20
30
40
0
1
2
3
4
T
o
t
a
l
L
e
a
k
a
g
%)
7000A leak current0 2 4 6 8 10
Substation Spacing, L (km)
leak current
vs vs.
. (, , )
/
/ / (BS EN 50162: 2004) ,
(KS C IEC 62128-2)( )
( /)
-
: , (2005) p.83
1010 9
8
10
9
8 8
7
8
7
6
6
5
5
4
4
3 4
3
3
2
191817161514
1313
12
11
10
9
8
76
5
4
3
22
1
/ /
I-beam
I-BEAM ()
() I beam I-beam / /
/ ()/ ()
1 2
[V][A]
[A] [A] [A] [A]
15.5 19.0 7.2 4.7 0.04 3.2 79% 15.5 18.9 - 9.9 4.2 4.7 100%
1 15.5 18.5 - - 0.9 12.9 75%
2 15.5 16.8 - - - 8.0 48%
15.5 14.6 - - - - 0%
// - : 19A 14.6A (23% ) 0 82 1 06 (30% )- : 0.82 1.06 (30% )
- 40
30
m
m
/
y
20
o
n
R
a
t
e
,
m
10
m
C
o
r
r
o
s
i
o
0
M
a
x
i
m
u
m
-800 -600 -400 -200 0 200
Potential mV/CSEPotential, mV/CSE
Rail spike
: 2-3 1.2m
61
- () ( ) (-)
Forced Drainage Bond Using a Potential Controlled Rectifier ( )( )
PotentialControlled
Is
ControlledRectifier
Is
structure buried referenceelectrode
() ()
() ()-0.5
Case Histories on Mitigation
-2.0
-1.5
-1.0
C
S
E
)
instant off 7.5A 12.5A
Case Histories on MitigationClients: KOGAS, KOWACO
-3.5
-3.0
-2.5
E
(
V
V
s
.
C
32 30 28 26 24 22 20 18-4.0
T/B No.
T3-14
R3-5
()R ()R
R3-4T3-15
C3-8 ()T
C ()
R3-3
T3-11
T3-12
C3-4
R4-4
R3-2
T3-10R4-2
R4-3R4-5
R4-6
R4-7
R3-1 C3-2
R4-1R4-8
T3-8
C3-7
T3-6T3-7
T3-4
T3-5
T3 2T4-9 T3-3
66
C3-6T3-2
C3-9
Corrosion Control of Underground PipelinesCorrosion Control of Underground Pipelines
Base metal: CS Coating + Cathodic Protection (CP)
()
, CP
Corrosion Protection Corrosion ProtectionTB
coating & lining () CP anodic protection corrosion inhibitor material selection Mg
: Mg, Al
+g : , +
-
Cathodic Cathodic Protection (CP)Protection (CP)Cathodic Cathodic Protection (CP)Protection (CP)
CPCP is achieved by supplyingis achieved by supplying ee-- to the metalto the metal CP CP is achieved by supplying is achieved by supplying ee to the metal to the metal structure structure to to be protected and widely used be protected and widely used in:in:
1) 1) long pipelineslong pipelines,,2) gas and oil transmission lines,2) gas and oil transmission lines,3) ships,3) ships,4) chemical processing 4) chemical processing equipments, etc.equipments, etc.
Eapp
Fe Cu Fe Cu
E E E
(a) before protection
EFeECu-EFe
(b) after protection
Galvanic (Sacrificial) Anode CP SystemGalvanic (Sacrificial) Anode CP SystemGalvanic (Sacrificial) Anode CP SystemGalvanic (Sacrificial) Anode CP System
CURRENTCURRENT
ANODEANODE
Impressed Current CP (ICCP) SystemImpressed Current CP (ICCP) SystemImpressed Current CP (ICCP) SystemImpressed Current CP (ICCP) SystemPowerSourceSource
+-
T T
CUR
CUR
C
U
R
R
E
N
T
C
U
R
R
E
N
T
RRENT
RRENT
ANODEANODE
Relative Economic Range for Galvanic and Impressed Current Systems F i f C R i d d S il R i i ias a Function of Current Required and Soil Resistivity
3 5
3.0
3.5
2 0
2.5Impressed Current
1.5
2.0
0.5
1.0Galvanic
10 20 30 40 50 60 70 80 90 1000
Soil Resistivity ( in ohm-m)
CP CP
73
CP CP
74
Effect of CPEffect of CP
NACE RP0169 Control of External Corrosion on
Underground or Submerged Metallic Piping Systems (potential criteria) -850mV
100mV 100mV
76
: -850mV vs Cu/CuSO4 : -850mV vs Cu/CuSO4 : -5,000mV P/S
Pipe to Soil () Pipe to Soil () : Sat. Cu/CuSO4
Ag/AgCl T/B T/B
300m - 500m
Equivalent Circuit for Corrosion Cell
ElectrochemicalReaction
ElectrochemicalReaction
Rct
R
RctResistance of Solution
Rsol
Anode CathodeDouble-layerCapacitance
Double-layerCapacitance
: Rsol
78
Voltage and Current Lines Around a Bare Pipeline R i i C th di P t ti C tReceiving Cathodic Protection Current
V
)
( )
ON Potential
V
)
( )
ON Potential
a
l
(
-
m
V
ON Potential
OFF Potential
IRIRON-IR -850 mVCSEOFF -850 mVCSEa l
(
-
m
V
ON Potential
OFF Potential
IRIRON-IR -850 mVCSEOFF -850 mVCSE
P
o
t
e
n
t
i
a
100 mV Polarization
OFF 850 mVCSE
P
o
t
e
n
t
i
a
100 mV Polarization
OFF 850 mVCSE
P
Native (Free Corroding Static) Potential
100 mV DepolarizationP
Native (Free Corroding Static) Potential
100 mV Depolarization
(+) Native (Free Corroding, Static) Potential(+) Native (Free Corroding, Static) Potential
80
81
P/S ( )P/S ( )
A
B
82
Reference Electrode Placed Close to Pipe Surface to Mi i i IR D E i P t ti l M t Minimize IR Drop Error in Potential Measurement
IR free Potential (Instant Off Method)IR-free Potential (Instant-Off Method)
V
)
( )
ON Potential
V
)
( )
ON Potential
a
l
(
-
m
V
ON Potential
OFF Potential
IRIRON-IR -850 mVCSEOFF -850 mVCSEa l
(
-
m
V
ON Potential
OFF Potential
IRIRON-IR -850 mVCSEOFF -850 mVCSE
P
o
t
e
n
t
i
a
100 mV Polarization
OFF 850 mVCSE
P
o
t
e
n
t
i
a
100 mV Polarization
OFF 850 mVCSE
P
Native (Free Corroding Static) Potential
100 mV DepolarizationP
Native (Free Corroding Static) Potential
100 mV Depolarization
Time
(+) Native (Free Corroding, Static) Potential(+) Native (Free Corroding, Static) Potential
Electrode for IR free Potential MeasurementElectrode for IR-free Potential Measurement
(polarization shift) (polarization shift) 100mV 100mV 100mV (, )
86
(polarization shift) (polarization shift)
87
Test Point Test Point - -500
-700
-600
-900
-800CP criteria
TB 315.4mA( m
V
C
S
E
)
-1100
-1000
TB 126.8mA
TB 414.7mA
TB 511.4mA
TB 6 TB 7
TB 80 mA
TB 925.2mA
p
o
t
e
n
t
i
a
l
-1300
-1200TB 255mA
19.2mA 34.3mA
P
/
S
0 1 2 3 4 5 6 7 8 9 10-1500
-1400
Distance (km) !!!Test points TPTP
Test Point Test Point - AbovegroundStorage Tank
Test / AccessStation
Storage Tank
Grade
f ll
Rim 25' Center 55' Rim
Reference CellMonitoring Tube
On -1411 -698 -404 -601 -1455Off -902 -664 -402 -578 -911
Potentials (mV)
Close Interval Potential Survey (CIPS)Close Interval Potential Survey (CIPS)
s
120od
Ls
Pin pointing of Coating DefectsPin-pointing of Coating Defects
DCVG (pulsed-direct current voltage gradient) method 3-4m
5
10
15
20
-15
-10
-5
0
5
Defect
P
o
t
e
n
t
i
a
l
D
i
f
f
e
r
e
n
c
e
(
m
V
)
0 1 2 3 4 5 6 7 8 9
-25
-20
Measure Point
Pipeline operators concern and solutionPipeline operator s concern and solution
Concern Solution
Is protective coating sound? DCVG *1
Is cathodic protection system working properly? CIPS*2p y g p p y
What extent and where is the corrosion damage (metal loss?)
ILI*3
Is pipelines having corrosion defects safe? What will be the life?
FFS*4
What will the appropriate remedial action? Internal ExpertConsulting Service
*1. Direct current voltage gradient method*2. Close interval potential survey*3. In-line inspection*4. Fitness-for-service
(External Corrosion Direct Assessment; ECDA)
ECDA (External Corrosion Direct Assessment)ECDA (External Corrosion Direct Assessment)
(CP) (CP) ,
- / (2003)
1MPa / / 15 1MPa / / 15 5 .
(Gas Transmission IM Rule), 49CFR192.923-931 (2003) 10 HCA (
5 ) 7
(ECDA) (pressure testing) e g In-line inspection (MFL-ILI) , e.g., In line inspection (MFL ILI)
ASME B31.8S Section 6.4 ASME B31.8S Appendix B2 & A3
NACE RP0502 (M th d l f ECDA) NACE RP0502 (Methodology for ECDA) Shall/Must Should Statements
ECDA ECDA PRE-ASSESSMENT
INDIRECT EXAM.
DIRECT EXAM.
POST ASSESSMENT
Risk Assessment
(region)
IMMEDIATE
( g ) CIPS/DCVG/
SCHEDULEDMONITORING
//
SEVEREMODERATEMINOR
1 1. - Pi l Pipe locator AC
30m
ECDA
Pre-assessment
(,TB, ) :CIPS,DCVG,,PCM
1 1. -
Active/passive corrosion
1 1. - 04-4
03-303-404-104-204-3
02 102-202-302-403-103-2
00 401-101-201-301-402-1
99 399-400-100-200-300-4
1 2 3 4 5 6 7 8 9
1
0
1
1
1
2
1
3
1
4
1
5
1
6
1
7
1
8
1
9
2
0
2
1
2
2
2
3
2
4
2
5
2
6
2
7
2
8
2
9
3
0
3
1
3
2
3
3
3
4
3
5
3
6
3
7
3
8
3
9
4
0
4
1
4
2
4
3
4
4
4
5
4
6
4
7
4
8
4
9
5
0
5
1
5
2
5
3
5
4
5
5
5
6
5
7
5
8
5
9
6
0
6
1
6
2
6
3
98-398-499-199-299-3
4 4 4 4 4 4 4 4 4 4
T/B NO.-2,500 --2,000 -2,000 --1,500 -1,500 --1,000 -1,000 --500 -500 -0
1 1.
()ECDA 1 ECDA 2 ECDA 3 ECDA 4 ECDA 5ECDA 1 ECDA 2 ECDA 3 ECDA 4 ECDA 5
CIPS
PCM
River
CIPS/DCVG PCM CIPS/DCVG
Sandy-Loam Sandy Sandy Loam
River
Sandy Loam
Medium
No History
Sandy
Well Drained
Low
Sandy
Well Drained
Med. Resist.
Loam
Poor Drainage
High
No History Some Problems Many Problems
1 2 3 CIPS(2) DCVG (ASP)
/ CIS DCVG
, (6) 50m, CIS PCM DCVG1. , 40-50m CIS2. 30m SCM3 1 2 DCVG3. 1, 2 DCVG
CIS DCVG (4)(5)(6) CIS DCVG , (4) CIS DCVG
CIS DCVG
1 CIS CIS PCM DCVG
1. CIS 2. 30m SCM 3. DCVG
Steel casing GSD 2124g () CIS DCVG encasement CIS DCVG
() () NACE RP0502 OO UNITS CpIS (ICCP) 1 - 3 m - 1.2-3m
-
mV (CSE)
DCVG 1 2 m % IR - / (dip) %IR
%IR Cathodic/anodic
cathodic/anodic
- %IR
Resistivity , 1/3 2/3
(50m)
cm(Wenner 4-pin method or soil box)
1/3, 2/3,
(50m)
PCM 18 45 20 PCM 18 45 m, 3 5 m
20mCIPS ,
(mA)
2 2. - TB, , ,
TB
2 2. -
(m) (mVCSE)
M01 6 -498 -511 -503
M02 864 126 -59 22
M03 1386 180 -5 88 TPM04 2028 230 70 150
M05 2970 540 100 320
M06 3186 168 -227 -24
M07 3732 920 560 740
M08 4494 84 432 285M08 4494 -84 -432 -285
M09 4908 148 -299 -97
M10 5748 -181 -598 -412
M11 5976 -219 -705 -432 TP
- (TB)
M12 6762 -235 -535 -427
M13 7488 -207 -483 -361
- (TB) - 600m-1Km 13
2 2. -
(< ~5,000 ohm.cm)
Wenner four pin Method Wenner four pin Method ~200m
2 (CIPS)2. (CIPS)
s
120od
Ls
CIPS ()CIPS ()
CIPS ()CIPS ()
CIPS (25 ft to 5 ft)CIPS (25 ft to 5 ft)5 ft interval
25 ft interval
2 2. - .
DCVG DCVG
2 2. -
Mg ( )
DCVG/CI Side DrainageDCVG/CI - Side Drainage
115
DCVG - %iRDCVG - %iR
5 ft interval
25 ft interval
%IR (NACE RP0502 2002)%IR (NACE RP0502-2002) Category 1: 1-15% IR:
.
Category 2: 16-35% IR: , . . .
Category 3: 36 60% IR: Category 3: 36-60% IR:
Category 2 .
-Category 4: 61-100% IR: .
117
.
1995-2002 DCVG
DCVG GPS SystemDCVG-GPS System
120
CIPS/DCVG CIPS/DCVG
PDAGPS Antenna Bluetooth communication
Push switchMeasure cablePDA screen touch operation
Pipeline Current Mapper(PCM) 4-8Hz ,
Pipe locator receiver (receiver
)
( ), ( ) ( )
Case I. ,
Case II. , ,
Case IIICase III./ ,
Case IV. short
C VCase V
Case VI ,/
PCM OO PCM OO transmitter , 4Hz, 1A
( ) , loss
transmitter Receiver
PCM PCM
100TB1 TB2 TB3 TB4
60
70
80
90
-
30
40
50
d
B
m
A
0
10
20
0 500 1000 1500 2000 2500 3000 3500 4000 4500Distance,m
TB DEFECT
2 ( )2. ( ) (static or dynamic) -
( ) (- ) - 0
() +()(STA 29+37.91)
-300
STA 73 80V 9A
900
-600
E
,
m
V
-1200
-900
-1500
-15 -10 -5 0 5 10 15
Distance, m
- ,
- : ~0.2A ( 9A 2.2%)
Carrier pipe casing Carrier pipe casing
128
CIS survey: river-crossing region DGPS coordinates measurement Stray current mapperCIS survey: river-crossing region
0
DGPS coordinates measurement Stray current mapper(SCM)
-1,500
-1,000
-500
-3,000
-2,500
-2,000
0 20 40 60 80 100 120 140 160 180 2000 20 40 60 80 100 120 140 160 180 200
No drilling DrillingCIS survey: asphalt road
-800
-600
-400
-200
0
-2000
-1800
-1600
-1400
-1200
-1000
250%IR
CIPS
0 300 600 900 1200 1500 1800 2100 2400 2700 3000 3300 3600
150
200
%IR
%IR
0
50
100
0 300 600 900 1200 1500 1800 2100 2400 2700 3000 3300 3600100000
1001000
10000
1
10
0 300 600 900 1200 1500 1800 2100 2400 2700 3000 3300 36002500
PCM2A 2A 2A
1000
1500
2000
PCM
0
500
1000
0 300 600 900 1200 1500 1800 2100 2400 2700 3000 3300 3600
PCM
CP Effectiveness (Pipeline Integrity) AssessmentCP Effectiveness (Pipeline Integrity) AssessmentField Survey
TB34
TB3TB33
TB35
TB2TB23
Pipe locator/SCMPipe Location
CP History
TB23
T1
TB26TB27
TB30
TB28
TB29
TB31
TB32
3TB25-1TB25
TB24
T2TB23-2TB23
-1
y
Rectifier/Test Point/Insulation FlangeInsulation Survey
Resistivity/Water 0
Resistivity/Water Content/MIC etc.Soil Corrosivity
CIPS/DCVG/PCM3433323130
282726
25-12523-2T223-1T1
23
-2500
-2000
-1500
-1000
-500
P
o
t
e
n
t
i
a
l
(
V
C
S
E
)
D2-8
-0.75V
-0.85V
D2-9
Steel CasingDC/AC Interference, etc.Special Region Exam.
Risk Assessment
2924
-30000 500 1000 1500 2000 2500 3000 3500 4000 4500
Distance from TB 23 (m)
Risk Assessment
Mitigation Action
Documentation
DIRECT EXAMINATION DIRECT EXAMINATION (urgency of excavation)
(Immediate action required) (Schedule for action required) (Suitable for monitoring)
/ feedback
(1 good coating) (1 good coating)1: DCVG*DCVG + Severe Moderate Minor NI
< 3,000 I* S* S* M*
3,000 7,000 I* S* M* M*(cm)
, ,
7,000 20,000 I* S* M* NI*
> 20,000 S* M* M* NI*
2: 1 1 + CIPS I* S* M* NICIPS Severe I S S M
Moderate I S M M
Minor I S M NI
NI S M M NI
* I: Immediate ( ) S: Scheduled ( ) M: Monitoring ( ) I: Immediate ( ), S: Scheduled ( ), M: Monitoring ( )
(2 poor coating) (2 poor coating)
(minor) (moderate) (severe)
CIPS -0.75V < off < -0.65V Off > -0.65V
> 10,000 cm 5,000 10,000 cm < 5,000 cm
CIPS I II
III
IV V
/ pH / p () ()
() (monitoring)() ( monitoring )
Coating defect found No disbonding Defect was protected perfectly by CP.
() (scheduled)() (scheduled)
Disbonded area Mechanical Damage Coating disbondment
No corrosion at crevice openingCorrosion occurred inside creviceDepth of disbondment: about 15 cm.
Crevice opening: pH>11Inside crevice: pH 6-7
() (immediate)() ( immediate )
pH pH (mV) (cm) STN
1
7 604 6 513
:10,362cm2
1 7 -604 6,513 :56cm2
: 12 25 70 2
2
7~9 -735 2,098:25 ~ 70cm2
: 12, 7
3
8 -562 2,538
:10,362cm2
:1,602cm2
:5.4 ~ 6.1cm2
4
8~9 -701 1,360
, , :7.6cm2~47cm2
Is corrosion is active or passive?Is corrosion is active or passive?
CASE 1: Active corrosion CASE 2: Passive corrosion
Types Potential (mV/CSE)
Pipe-to-Soil Potential -1430 to -1200
Potential inside crevice -610 to -550
OFF OFF
pH pH
, OH- pH
OHHeOH 222 22 pH 1) 2) pH (
) )
3) pH pH
pH pH>10~11
. vs. pH
,
. p pH< 8
, pH
.
4 4.
ECDA
Maximum pit depth/burial time 0.4 mm/y*1
0 3 / l 0 C 0.3 mm/y at least 40mV CP
LPR measurement (ASTM G59) + pitting index LPR measurement (ASTM G59) + pitting index Corrosion coupon
*1. Upper 80% confidence level of maximum pitting rates for long term (up to 17y) underground corrosion tests ofbare pipe coupons without CP in a variety of soils including native and non-native backfill.
tSM850RL PP
GRt
SM85.0RL YIELD
MAOP
YIELD
FAIL
PP
PP
SM FOR: YIELDYIELD
3300
FOR:
SM (safety margin) = 0.6
GR () = 10 mil/yr.yr8.16
010.330.0
)6(.85.0RL ( ) /y
T () = 0.330
1/2 ECDA !!!
ECDA DCVG ECDA DCVG .
DCVG , ECDA .
. DCVG ECDA .
ECDA , , feedback
Availability of ECDA Tools (cf NACE RP0502)Availability of ECDA Tools (cf. NACE RP0502)CIPS DCVG Pearson EM AC Attenuation
Coating holidays 2 1,2 2 2 1,2
Anodic zone or bare pipe 2 3 3 3 3
Near river or water crossing 2 3 3 2 2
Under frozen ground 3 3 3 2 1,2
S 2 1 2 2 2 1 2Stray currents 2 1,2 2 2 1,2
Shielded corrosion activity (heat-shrink sheet) 3 3 3 3 3
Adjacent metallic structures 2 1,2 3 2 1,2
Near parallel pipelines 2 1,2 3 2 1,2Near parallel pipelines 2 1,2 3 2 1,2
Under HVAC overhead electric transmission lines 2 1,2 2 3 3
Shorted casing 2 2 2 2 2
Under paved roads 3 3 3 2 1,2
Uncased crossing 2 1,2 2 2 1,2
Cased piping 3 3 3 3 3
At deep burial locations 2 2 2 2 2
W tl d (li it d) 2 1 2 2 2 1 2Wetlands (limited) 2 1,2 2 2 1,2
Rocky terrain/rock ledges/rock backfill 3 3 3 2 2
*1: - (
Corrosion under Disbonded CoatingCorrosion under Disbonded Coating
147
PtRef2PipeRef1 p
1. Ref 1 vs. Pipe 2. Ref 2 vs. Pipe 3. Ref 2 vs. Pt
Potential mV vs. Cu/CuSO4
P/S -1430 (-1200)
In Crevice -610 (-500)
Pt Electrode -480
Redox -160 (vs. NHE)*1
*1 At H 7
148
*1. At pH 7
C i P t ti l M t U d Di b d d C tiC i P t ti l M t U d Di b d d C tiCrevice Potential Measurement Under Disbonded CoatingCrevice Potential Measurement Under Disbonded Coating
Holiday potential -1.0V/CSE
NaCl 0.001M, 8350cm NaCl 0.005M, 1755cm NaCl 0.05M, 195cm
: /
Disbonded coating (PUF), DCVG ( )/ / ( )
ECDA + ILI ()
ILI (GRI 02/0087) ILI (GRI-02/0087) 33% ILI (2002)
75% ILI 40 ( )
25% unpiggable ILI
ECDA (25% (42%)) ECDA . (25% + (42%))
ECDA+ILI (KOGAS )ECDA+ILI (KOGAS ) /
Geometry pig
ILI /(Defect Assessment)
Geometry pigMFL pig
(CIPS)
/
()
(ECDA)/
ILI-MFLILI-MFL
. (threshold value)
.
GPS WirelessGPSGIS
Satellite Communication
WirelessNetworks
Rectifier RectifierTB 1 TB 2
Remote Remote
ReferenceElectrode
ReferenceElectrode
Remote MonitoringData Logger
Remote ControlRectifier
Remote MonitoringData Logger
Remote ControlRectifier
ElectrodeElectrode
Anode AnodeCurrent
157
[ ] [ ]
SCR type SMPS typeSCR type SMPS type
- (on/off) GPS 10 msec
Installation & Operation Status in KoreaInstallation & Operation Status in Korea
Gas transmission pipelines Gas transmission pipelines ~150 km of total 3,000 km is covered by
RemoteCPMSTM
Municipal water pipelines Municipal water pipelines ~50km of total 3,000km is covered
Samsung BP Chemical pipeline ~ 5km
Gas distribution pipeline (Mokpo) 5km ~ 5km
InstalledPlanned (2009)FutureFuture
Economic Feasibility Study on Remote CP MonitoringExample: CP Maintenance Cost for Water Pipelines in Koreap p
80
60
70 Remote MonitoringManual Maintenance
50
C
o
s
t
30
40
R
e
l
a
t
i
v
e
20
Assumption:
10Assumption:- Lifespan: 15 y- One rectifier + Two TB in 2km region
0 5 10 15 20 25 30
Operation Period (yr)
10
9
8OO
= -2.5VCSE(-), (+) 7
6
R
T
CW ()
5
4
OOOO
OO
3
2
2
1
OO
vs. 4 2
3 P/S 4 P/S 2 P/S
35+25=60(A)35+25=60(A)
/ /
16
M MCIPS (data logger)
(#13, #26, #28, #30)
() ()R19 on/off, 25 (on/off 27mV) R15 on/off, 13 (on/off 192mV)
R18 on/off, 21 (on/off -1756mV) / , ( / )
R17 on/off, 17 (on/off -74mV)
20mV
() () (m R1 R2 R3 R4 R5 R7 R8 R9 R11 R12 R13 1 R13 2 R13 3 R14 R15 R17 R18 R19 R20 R21 R22 R23 R24 R25
) R1 R2 R3 R4 R5 R7 R8 R9 R11 R12 R13-1 R13-2 R13-3 R14 R15 R17 R18 R19 R20 R21 R22 R23 R24 R25
30 -1000 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 13 6 M1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 192 0 0 0 0 0 0 0 0 0 14 864 M2 0 0 0 0 0 0 0 0 0 0 0 0 0 0 36 0 0 0 0 0 0 0 0 0 15 2028 M4 0 0 0 0 0 0 0 0 0 0 0 0 0 0 28 0 24 0 0 0 0 0 0 28 18 2364 0 0 0 0 0 0 0 0 0 0 0 0 0 0 69 50 36 0 0 0 0 0 0 30 16 2970 M5 0 0 0 0 0 0 0 0 0 0 0 0 0 0 29 0 43 0 0 0 0 0 0 45 17 3186 M6 0 0 0 0 0 0 0 0 0 0 0 0 0 0 31 -74 100 0 0 0 0 0 0 43 19 3504 D2 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 -23 94 0 0 0 0 0 0 0 20 3732 M7 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 -22 208 0 0 0 0 0 0 0 21 4380 0 0 0 0 -200 0 0 0 0 0 0 0 0 0 0 0 -1756 0 0 0 0 0 0 0 22 4908 M9 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 258 0 26 0 0 0 0 022 4908 M9 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 258 0 26 0 0 0 0 0 23 5748 M10 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 43 0 0 0 0 0 24 6762 M12 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 49 29 0 0 0 0 0 25 7488 M13 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 27 0 0 0 0 0 0 26 7650 End 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 43 0 0 0 0 0 0 28 8650 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 76 0 0 0 0 0
, () (ECDA,
ILI )
IT ()
() () Design can never be absolute.
A designer is seldom a corrosion engineer. Unlike conventional engineering, the basic difficulty is that
corrosion is not a tangible propertycorrosion is not a tangible property. Decisions are often a compromise based on cost and availability of
materials and resources.
Communication is important.C i i f d f f il l Communication of agreed reasons for failures may not always reach the designer. (ASM Metals Handbook, Vol. 13A) Site personnel: 77%p Designers: 55% Materials suppliers: 37%
C t t 11% Contractors: 11%
THE ENDTHE END