measuring corrosion and corrosion control (cc) on...
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Measuring Corrosion and Measuring Corrosion and Corrosion Control (CC) on Corrosion Control (CC) on
W Pi M i lW Pi M i lWater Pipe MaterialsWater Pipe Materials
Graham E.C. Bell, Ph.D., P.E.Graham E.C. Bell, Ph.D., P.E.
Water/Wastewater ForumWater/Wastewater ForumCorrosion: Why Should I Be Concerned?Corrosion: Why Should I Be Concerned?
Corrosion 2010/San AntonioCorrosion 2010/San Antonio
CC in the Water Industry is Fundamentally CC in the Water Industry is Fundamentally Different from CC in Oil & Gas Different from CC in Oil & Gas
Pipe Materials, Coatings and LiningsPipe Materials, Coatings and Linings CIP, DIP, Steel, and Reinforced/PreCIP, DIP, Steel, and Reinforced/Pre--stressed/tension stressed/tension
ConcreteConcrete Mortar and Concrete Coatings and LiningsMortar and Concrete Coatings and Liningsg gg g PushPush--on NOT Welded Jointson NOT Welded Joints
Lack of Regulatory Requirement for Corrosion Lack of Regulatory Requirement for Corrosion Control and Monitoring.Control and Monitoring. Cathodic Protection is the last resort of a desperate water Cathodic Protection is the last resort of a desperate water
corrosion engineer.corrosion engineer. Corrosion Control tends to be more passive and buried Corrosion Control tends to be more passive and buried
with the asset.with the asset.
Ferrous Pipe MaterialsFerrous Pipe Materials Steel Pipe AWWA Steel Pipe AWWA
C200C200 Dielectric CoatingDielectric Coating
AWWA C203AWWA C203 AWWA C210AWWA C210 AWWA C214AWWA C214 AWWA C222AWWA C222
Ductile Iron Pipe Ductile Iron Pipe AWWA C151AWWA C151 AWWA C105AWWA C105
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Mortar/Concrete Encased SteelMortar/Concrete Encased Steel Mortar Coated Steel Mortar Coated Steel
Pipe Pipe AWWA AWWA
C200+C205C200+C205
Concrete PipeConcrete Pipe AWWA C300AWWA C300 AWWA C301AWWA C301 AWWA C302AWWA C302 AWWA C303AWWA C303
Focus on Corrosion MonitoringFocus on Corrosion Monitoring
Oil & Gas Corrosion Monitoring Focuses on Oil & Gas Corrosion Monitoring Focuses on Adequacy of Cathodic Protection for Adequacy of Cathodic Protection for Compliance.Compliance.
Water Industry focuses on asset preservation Water Industry focuses on asset preservation Water Industry focuses on asset preservation Water Industry focuses on asset preservation and capital conservationand capital conservation
Measuring Measuring --850 is not sufficient 850 is not sufficient in the Water Industryin the Water Industry
Regulatory Compliance monitoring is Regulatory Compliance monitoring is fundamentally different.fundamentally different.
NACE standards focus on measurement of NACE standards focus on measurement of pipe or structure to electrolyte potential pipe or structure to electrolyte potential pipe or structure to electrolyte potential pipe or structure to electrolyte potential measurements (SPmeasurements (SP--0169).0169).
Asset Preservation and Capital Conservation Asset Preservation and Capital Conservation Requires Requires measuringmeasuring corrosion damage or corrosion damage or corrosion rate.corrosion rate.
Fundamentally, we need to measure Fundamentally, we need to measure corrosion current (corrosion current (iicorrcorr) or mils lost.) or mils lost.
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Use of CP with Ferrous Water Use of CP with Ferrous Water Pipe Materials is SpottyPipe Materials is Spotty
More common on NEW large diameter steel More common on NEW large diameter steel transmission pipelines with dielectric coatings.transmission pipelines with dielectric coatings.
Retrofitting of existing ferrous pipelines occurs Retrofitting of existing ferrous pipelines occurs when leak rates become unacceptable.when leak rates become unacceptable.pp
CP of DIP is a controversial subject.CP of DIP is a controversial subject. Most DIP is installed with out protectionMost DIP is installed with out protection Small percentage with polyethylene encasement Small percentage with polyethylene encasement
(PE)(PE) Even smaller percentage installed with PE and CP Even smaller percentage installed with PE and CP
or even just CP.or even just CP.
Methods for Measuring Methods for Measuring CorrosionCorrosion
SurrogatesSurrogates CouponsCoupons ProbesProbes
Electrical Resistance Electrical Resistance (ER)(ER)
Electrochemical Electrochemical TechniquesTechniques Linear PolarizationLinear Polarization Advanced Advanced
Electrochemical Electrochemical MethodsMethods
Principals of Operation for ER Principals of Operation for ER ProbesProbes
Thin cross section of Thin cross section of metal corrodes.metal corrodes.
As metal thins As metal thins uniformly resistance of uniformly resistance of uniformly, resistance of uniformly, resistance of the strip increases.the strip increases.
Changes in resistance Changes in resistance of strip record metal of strip record metal loss (corrosion damage)loss (corrosion damage)
Slope of line is the Slope of line is the corrosion rate.corrosion rate.
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MEASUREREFERENCE
C
D
CORROSION ENVIRONMENTPROBE INTERNAL
EF
CHECK
WIRE LOOP ER PROBE SCHEMATICWIRE LOOP ER PROBE SCHEMATIC
A
B
ACDRIVE
B – C = MEASURE
C – D = REFERENCE
D – E = CHECK
Installation of ER ProbesInstallation of ER Probes
Field TestsField TestsCathodic Protection and ER Probes in Soil works!Cathodic Protection and ER Probes in Soil works!
SANTA MARGARITA PROBE TESTCORROSION LOSS
1.20
1.40
1.60
1.80
S (
mil
s)
CONNECT C.S. TO PIPE
0.00
0.20
0.40
0.60
0.80
1.00
0 200 400 600 800 1000 1200
TIME (DAYS)
CO
RR
OS
ION
LO
SS
CARBON STEEL
DUCTILE IRON
5
Continuing Field TestsContinuing Field TestsCR on DIP Probe w/o CP similar to Bare Steel with CPCR on DIP Probe w/o CP similar to Bare Steel with CP
SANTA MARGARITA PROBE TESTCORROSION RATE
5.0
6.0
7.0
PY
)
CONNECT C.S.TO PIPE
-1.0
0.0
1.0
2.0
3.0
4.0
0 200 400 600 800 1000 1200
TIME (DAYS)
CO
RR
OS
ION
RA
TE
(M
P
CARBON STEEL
DUCTILE IRON
Mortar or Concrete Coated SteelMortar or Concrete Coated Steel Commonly used in water industry.Commonly used in water industry. High pH environment High pH environment passivatespassivates and and
protects steel.protects steel. Typical Pipe to Soil PotentialsTypical Pipe to Soil Potentialsyp pyp p
Bare, Coated or Bare, Coated or depassivateddepassivated mortar coated steel mortar coated steel –– 400 to 400 to --700 700 mvmv vs. CSEvs. CSE
PassivatedPassivated Steel in high pH environmentSteel in high pH environment0 to 0 to --200 200 mvmv vs. CSEvs. CSE
Mortar Coated Steel tells you when it is in Mortar Coated Steel tells you when it is in trouble.trouble.
Change in Mortar Encased Steel Change in Mortar Encased Steel Potential with TimePotential with Time
PRE-STRESSING WIRE ER PROBE TEST
90.0
100.0
110.0
120.0
ION
S)
-300.0
-200.0
-100.0
SE
0.0
10.0
20.0
30.0
40.0
50.0
60.0
70.0
80.0
0
30
60
90
12
0
15
0
18
0
21
0
24
0
27
0
30
0
33
0
36
0
39
0
42
0
45
0
48
0
51
0
54
0
57
0
60
0
63
0
66
0
69
0
72
0
75
0
78
0
81
0
84
0
87
0
TIME IN DAYS
CK
-3 R
EA
DIN
G (
DIV
ISI
-800.0
-700.0
-600.0
-500.0
-400.0
PO
TE
NT
IAL
VS
. C
S
PROBE 1 CORROSION PROBE 2 CORROSION PROBE 1 POTENTIAL PROBE 2 POTENTIAL
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How to Monitor Mortar or How to Monitor Mortar or Concrete Encased SteelConcrete Encased Steel
Make the pipeline intentionally electrically Make the pipeline intentionally electrically continuous so you can monitor it.continuous so you can monitor it.
Install Test Stations and Use themInstall Test Stations and Use them
Measure base line pipe Measure base line pipe to soil potentialsto soil potentials
L k f hL k f h Look for changesLook for changes
Don’t collect, file and Don’t collect, file and forget.forget.
Change in Mortar Encased Steel Change in Mortar Encased Steel Potential Tells You the Pipe Is Not Potential Tells You the Pipe Is Not
Happy!Happy!PRE-STRESSING WIRE ER PROBE TEST
90.0
100.0
110.0
120.0
ION
S)
-300.0
-200.0
-100.0
SE
0.0
10.0
20.0
30.0
40.0
50.0
60.0
70.0
80.0
0
30
60
90
12
0
15
0
18
0
21
0
24
0
27
0
30
0
33
0
36
0
39
0
42
0
45
0
48
0
51
0
54
0
57
0
60
0
63
0
66
0
69
0
72
0
75
0
78
0
81
0
84
0
87
0
TIME IN DAYS
CK
-3 R
EA
DIN
G (
DIV
ISI
-800.0
-700.0
-600.0
-500.0
-400.0
PO
TE
NT
IAL
VS
. C
S
PROBE 1 CORROSION PROBE 2 CORROSION PROBE 1 POTENTIAL PROBE 2 POTENTIAL
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Early ECEarly EC--PCCP SectionPCCP Section1.5 m to 6.5 m diameter1.5 m to 6.5 m diameter
PrePre--Stressing Wire ER ProbeStressing Wire ER Probe
PrePre--stressing wire used as stressing wire used as probeprobe
InIn--situ presitu pre--stressingstressingcan be “wired” as acan be “wired” as aprobeprobe
Probe can be used as a Probe can be used as a “proxy” on mortar coated “proxy” on mortar coated jointsjoints
Need to provide mortar Need to provide mortar environment.environment.
PrePre--Stressing Wire ER Probe TestingStressing Wire ER Probe Testing
PRE-STRESSING WIRE ER PROBE TEST
70 0
80.0
90.0
100.0
110.0
120.0
IVIS
ION
S)
-300.0
-200.0
-100.0
S.
CS
E
0.0
10.0
20.0
30.0
40.0
50.0
60.0
70.0
0
30
60
90
12
0
15
0
18
0
21
0
24
0
27
0
30
0
33
0
36
0
39
0
42
0
45
0
48
0
51
0
54
0
57
0
60
0
63
0
66
0
69
0
72
0
75
0
78
0
81
0
84
0
87
0
TIME IN DAYS
CK
-3 R
EA
DIN
G (
D
-800.0
-700.0
-600.0
-500.0
-400.0
PO
TE
NT
IAL
VS
PROBE 1 CORROSION PROBE 2 CORROSION PROBE 1 POTENTIAL PROBE 2 POTENTIAL
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Linear Polarization Resistance (LPR)Linear Polarization Resistance (LPR)
•• LPR LPR is a measurement technique that is a measurement technique that provides a direct electrochemical provides a direct electrochemical measurement of corrosion rate in a measurement of corrosion rate in a conductive conductive electrolyte (soil or water)electrolyte (soil or water)
h d f llh d f ll•• The measurement is made from two small The measurement is made from two small electrodes made from the material (metal or electrodes made from the material (metal or alloy) of interestalloy) of interest..
•• The determination of the corrosion rate is The determination of the corrosion rate is calculated from a series of electronic calculated from a series of electronic measurements measurements
The LPR Equivalent CircuitThe LPR Equivalent Circuit
RP RPRS
Electrode 1
Electrode 2
RRPP = Polarization Resistance= Polarization ResistanceRRss = Solution Resistance= Solution ResistanceCCdldl = Double Layer Capacitance= Double Layer Capacitance
Cdl Cdl
1
The “behavior” of a metal in an The “behavior” of a metal in an electrolyteelectrolyte
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DIP + OX DIP + No OX DIP + BS
10,000
12,000
14,000
16,000
AN
CE
(o
hm
-cm
^2)
-1000
-900
-800
-700
EN
TIA
L (
mV
)
LPRLPR--Bare Carbon SteelBare Carbon Steel
0
2,000
4,000
6,000
8,000
0 10 20 30 40 50 60 70
DAYS
PO
LA
RIZ
AT
ION
RE
SIS
TA
-600
-500
-400
-300
-200
RE
FE
RE
NC
E P
OT
E
LPRReference Potential
10
4 000
5,000
6,000
7,000
AN
CE
(o
hm
-cm
^2)
-980
-960
-940
-920 EN
TIA
L (
mV
)
LPR LPR –– DIP No OXDIP No OX
0
1,000
2,000
3,000
4,000
0 10 20 30 40 50 60 70
DAYS
PO
LA
RIZ
AT
ION
RE
SIS
TA 920
-900
-880
-860
-840
RE
FE
RE
NC
E P
OT
E
LPR
Reference Potential
15,000
20,000
25,000
NC
E (
oh
m-c
m^
2)
-1000
-960
-920 NT
IAL
(m
V)
LPR LPR –– DIP + OXDIP + OX
0
5,000
10,000
15,000
0 10 20 30 40 50 60 70
DAYS
PO
LA
RIZ
AT
ION
RE
SIS
TA
N 920
-880
-840
-800
RE
FE
RE
NC
E P
OT
EN
LPR
Reference Potential
DIP + OX DIP + No OX DIP + BS
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LPR on Coated SteelLPR on Coated Steel
250,000
300,000
350,000
CE
(o
hm
-cm
^2)
-970
-950
-930
TIA
L (
mV
)
0
50,000
100,000
150,000
200,000
0 5 10 15 20 25 30 35 40 45
DAYS
PO
LA
RIZ
AT
ION
RE
SIS
TA
N
-910
-890
-870
-850
-830
RE
FE
RE
NC
E P
OT
EN
T
LPR
Reference Potential
EIS EIS –– Coated 1010Coated 1010
EN Showing SCCEN Showing SCC
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Other Possible Electrochemical Other Possible Electrochemical MeasurementsMeasurements
Electrochemical Impedance Spectroscopy Electrochemical Impedance Spectroscopy (EIS)(EIS)
Electrochemical Noise (EN)Electrochemical Noise (EN)E E Etc., etc., ….Etc., etc., ….
The point is that we can measure and The point is that we can measure and estimate corrosion rates on ferrous metals estimate corrosion rates on ferrous metals very well and relatively accurately using very well and relatively accurately using surrogates.surrogates.
Design and Long Term Current Design and Long Term Current Requirements for Water Pipe Requirements for Water Pipe
MaterialsMaterials
ConclusionsConclusions Motivation for Corrosion Control is Motivation for Corrosion Control is
Different in Water and Wastewater than it is Different in Water and Wastewater than it is in Oil & Gasin Oil & Gas
Asset Preservation requires measuring Asset Preservation requires measuring corrosion rates rather than assuring corrosion rates rather than assuring corrosion rates rather than assuring corrosion rates rather than assuring compliance.compliance.
We can measure corrosion rates using We can measure corrosion rates using surrogates.surrogates.
Data need to be turned into actionable Data need to be turned into actionable information. If you are not going to do information. If you are not going to do anything, remain ignorant.anything, remain ignorant.
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Thank you for your timeThank you for your time
Q i ?Q i ?Questions?Questions?