Post on 13-Apr-2018
7/27/2019 DOT Pipeline Corrosion
http://slidepdf.com/reader/full/dot-pipeline-corrosion 1/31
ABC Chemical Complex 1
Corrosion Control
and Monitoring
ABC Company
ABC Chemical ComplexEngineering Specification
7/27/2019 DOT Pipeline Corrosion
http://slidepdf.com/reader/full/dot-pipeline-corrosion 2/31
ABC Chemical Complex 2
Corrosion Control & Monitoring
SCOPE
– This Engineering Specification includes
external and internal corrosion control and
monitoring for DOT regulated pipelines.
– Design, construction, construction inspection,
construction acceptance, operation, and
maintenance of DOT regulated pipelines arecovered by this Engineering Specification.
7/27/2019 DOT Pipeline Corrosion
http://slidepdf.com/reader/full/dot-pipeline-corrosion 3/31
ABC Chemical Complex 3
Corrosion Control &Monitoring
GENERAL
– All DOT regulated ABC pipelines require
protection from the environment.
– Corrosive elements in the pipeline stream must
be neutralized or the pipe material must be
resistant to the stream.
7/27/2019 DOT Pipeline Corrosion
http://slidepdf.com/reader/full/dot-pipeline-corrosion 4/31
ABC Chemical Complex 4
Corrosion Control & Monitoring
Minimum requirements for corrosion
control:
– External Corrosion Control
» Buried DOT regulated pipelines will be coated and
cathodically protected
– Internal Corrosion Control
» Known corrosion rate based on historical data» Corrosion rate from a national standard data base
» Data collected from laboratory prototype testing
7/27/2019 DOT Pipeline Corrosion
http://slidepdf.com/reader/full/dot-pipeline-corrosion 5/31
ABC Chemical Complex 5
Corrosion Control & Monitoring
Minimum requirements for corrosion
control (Continued):
– Above Ground External Corrosion Control
» Coat with an approved system with resistance to the
soil and internal fluid temperature
7/27/2019 DOT Pipeline Corrosion
http://slidepdf.com/reader/full/dot-pipeline-corrosion 6/31
ABC Chemical Complex 6
Corrosion Control & Monitoring
REFERENCES
– NACE RP 0169-92
– Surface Preparation:» NACE No. 1, SSPC-SP 5, White Metal Blast
Cleaning
» NACE No. 2, SSPC-SP 10, Near White Metal Blast
» NACE No. 3, SSPC-SP6, Commercial Blast» NACE No. 4, SSPC-SP 7, Brush-Off Blast
7/27/2019 DOT Pipeline Corrosion
http://slidepdf.com/reader/full/dot-pipeline-corrosion 7/31ABC Chemical Complex 7
Corrosion Control & Monitoring
PERSONNEL REQUIREMENTS
– Engineering design will be performed by a
Corrosion Engineer with training and
experience in the proposed corrosion control
system.
– Coating, lining, and painting inspection will be
performed by an inspector with appropriatetraining and experience.
7/27/2019 DOT Pipeline Corrosion
http://slidepdf.com/reader/full/dot-pipeline-corrosion 8/31ABC Chemical Complex 8
Corrosion Control & Monitoring
PERSONNEL REQUIREMENTS (Cont..)
– Cathodic protection installations will be
inspected by an inspector with training and
experience in cathodic protection inspection.
– Internal corrosion monitoring installations will
be inspected by an inspector with training and
experience in internal corrosion monitoringinspection.
7/27/2019 DOT Pipeline Corrosion
http://slidepdf.com/reader/full/dot-pipeline-corrosion 9/31ABC Chemical Complex 9
Corrosion Control & Monitoring
DESIGN REQUIREMENTS, EXTERNAL
– Cathodic Protection Criteria
» Buried Onshore Pipelines: Pipe-to-soil potential
equal to or more negative than -0.85 volts
referenced to copper-copper sulfate electrode and
recorded immediately after current interruption
(Instant-off potential).
» Offshore Pipelines: Pipe-to-water potential equal toor more negative than -0.80 volts referenced to a
silver-silver chloride electrode with “instant off”
potential reading.
7/27/2019 DOT Pipeline Corrosion
http://slidepdf.com/reader/full/dot-pipeline-corrosion 10/31ABC Chemical Complex 10
Corrosion Control & Monitoring
» Tank Bottoms: Steel-to-soil potential equal to or
more negative than -0.85 volts with a copper-copper
sulfate half cell and “instant off” potential.
» Maximum pipeline potential: Equal to or less than -1.5 volts to a standard copper-copper sulfate half
cell with the current temporarily interrupted.
7/27/2019 DOT Pipeline Corrosion
http://slidepdf.com/reader/full/dot-pipeline-corrosion 11/31ABC Chemical Complex 11
Corrosion Control & Monitoring
– Coating Requirements
» New buried pipe sections shall be coated with one of
the following types:
Fusion bonded epoxy Coal tar epoxy
Polyolefin tape
Prefabricated films
Other coating systems approved by Central Engineering
» Surface preparation shall be in accordance with
manufacturer’s recommendation and Appendix B.
7/27/2019 DOT Pipeline Corrosion
http://slidepdf.com/reader/full/dot-pipeline-corrosion 12/31ABC Chemical Complex 12
Corrosion Control & Monitoring
Methods Used for Cathodic Protection
– Galvanic Anode Systems
» Provide protection to the structure by the potential
difference generated by the electrochemical reaction
between the structure and the anode through a soil
or water electrolyte.
» Typically used in soil or water with resistivity less
than 5000 ohm-cm.
7/27/2019 DOT Pipeline Corrosion
http://slidepdf.com/reader/full/dot-pipeline-corrosion 13/31ABC Chemical Complex 13
Corrosion Control & Monitoring
– Methods Used For Cathodic Protection (Cont)
» Impressed Current Systems
Uses external source of DC power, usually an AC trans-
former with an AC to DC rectifier, to provide the drivingvoltage to the structure to be protected.
Potential difference between the anode and the structure
creates current flow from the anode into the soil and onto
the pipeline.
Used when the soil resistivity exceeds 5000 ohm-cmand/or more than 5 amperes of impressed current are
required.
7/27/2019 DOT Pipeline Corrosion
http://slidepdf.com/reader/full/dot-pipeline-corrosion 14/31
ABC Chemical Complex 14
Corrosion Control & Monitoring
– Equipment
» Galvanic Anode Systems
Anode: Magnesium onshore, Galvalum III offshore.
Junction box to connect leads from structure and anode.» Impressed Current Systems
DC transformer/rectifier (supplied as a unit).
Anode(s) with inert or low reactivity characteristics.
Terminal box with resistors to adjust current flow to eachanode or anode string.
7/27/2019 DOT Pipeline Corrosion
http://slidepdf.com/reader/full/dot-pipeline-corrosion 15/31
ABC Chemical Complex 15
Corrosion Control & Monitoring
– Miscellaneous
» Install lightning arrestors.
» Provide electrical isolation: Insulating flanges or
spools.» Minimize interference with bonding stations.
» Install test stations to measure potentials.
» Complete the following documentation:
Bonding and/or anode bed data sheet.
Bonding station data sheet.
Test station data sheet.
7/27/2019 DOT Pipeline Corrosion
http://slidepdf.com/reader/full/dot-pipeline-corrosion 16/31
ABC Chemical Complex 16
Corrosion Control & Monitoring
– Impact on Operating Equipment
» Apply NEMA electrical-class safety requirements to
all equipment associated with impressed current
installations.» Install CP equipment in areas not requiring
intrinsically safe design.
» Locate anode beds to minimize effect on other
structures and to minimize mechanical damage fromforeign construction.
7/27/2019 DOT Pipeline Corrosion
http://slidepdf.com/reader/full/dot-pipeline-corrosion 17/31
ABC Chemical Complex 17
Corrosion Control & Monitoring
» Perform interference testing on all equipment that
may be damaged by the new CP installation.
Testing shall include, but is not limited to, the
following situations:
Pipelines crossing within 5 feet.
Metal Structures within 5 feet of the pipeline.
Metal Structures within 200 feet of the anode bed.
7/27/2019 DOT Pipeline Corrosion
http://slidepdf.com/reader/full/dot-pipeline-corrosion 18/31
ABC Chemical Complex 18
Corrosion Control & Monitoring
– Impact on Operating Equipment
» Design CP systems with capacity for current loss
through interference bonds and future current loss
due to coating deterioration.» Minimize casing installations for protection of the
carrier pipe. Perform interference testing as shown
in Company Corrosion Control & Monitoring
Specification Appendix E. Provide bonding stations
for each casing installation.
7/27/2019 DOT Pipeline Corrosion
http://slidepdf.com/reader/full/dot-pipeline-corrosion 19/31
ABC Chemical Complex 19
Corrosion Control & Monitoring
DESIGN REQUIREMENTS, INTERNAL
– Corrosive chemicals in the pipeline stream
» May reduce stream (liquid or gas) quality or
» Cause general thinning or pitting attack
» Shall be handled by one of the following methods:
Neutralization or removal of the corrosive chemicals.
Select a pipe material which is resistant.
Coat the internal surfaces of the pipe.
7/27/2019 DOT Pipeline Corrosion
http://slidepdf.com/reader/full/dot-pipeline-corrosion 20/31
ABC Chemical Complex 20
Corrosion Control & Monitoring
– Design package will contain:
» Provisions for upset/emergency conditions.
» Recommended corrosion monitoring program.
» Recommended corrosion monitoring equipment.
» Installation of personnel safety devices and
platforms required for safe performance of duties.
» Pigging procedure when pigging facilities are
included in the design package.
» Compliance with regulations of local, state, and
federal jurisdiction for pigging procedures.
7/27/2019 DOT Pipeline Corrosion
http://slidepdf.com/reader/full/dot-pipeline-corrosion 21/31
ABC Chemical Complex 21
Corrosion Control & Monitoring
– Documentation Requirements
» Determine thickness measurement locations
(TML’s) based on the most probable locations for
corrosion or erosion-corrosion damage. SelectTML’s with the assistance of the Corrosion
Engineer.
» Collect baseline thickness readings on all new
installations.
» Install corrosion monitoring equipment where the
“worst case” corrosion attack is expected.
» Provide corrosion monitoring data sheets.
7/27/2019 DOT Pipeline Corrosion
http://slidepdf.com/reader/full/dot-pipeline-corrosion 22/31
ABC Chemical Complex 22
Corrosion Control & Monitoring
DESIGN REQUIREMENTS, ABOVE
GROUND EXTERNAL
– Coat with a coating system that is recom-
mended for the environment.
– Prepare surface in accordance with external-
coating-system manufacturer’s
recommendations. See Company CorrosionControl & Monitoring Specification Appendix
B.
7/27/2019 DOT Pipeline Corrosion
http://slidepdf.com/reader/full/dot-pipeline-corrosion 23/31
ABC Chemical Complex 23
Corrosion Control & Monitoring
INSTALLATION
– Quality Control, External Systems
» Coatings
Qualified Inspector presence - 100%.
Field applied coating systems - 100% inspection.
Shop applied coating systems - 100% inspection.
Coating repairs - 100% inspection.
Protect all stored coating materials at the construction sitefrom weather, particularly directly sunlight and heat.
7/27/2019 DOT Pipeline Corrosion
http://slidepdf.com/reader/full/dot-pipeline-corrosion 24/31
ABC Chemical Complex 24
Corrosion Control & Monitoring
» Pad in the pipe trench
Inspect just prior to laying the pipe in the trench.
Remove all trash and construction debris.
» Cables
Inspect upon receipt at job site to detect nicks and damage.
100% inspection at the mill with proper mill cert..
Avoid damaging cable insulation during installation.
Splice cables aboveground in terminal boxes.
Use non-conductive conduits for cable installation.
Make cathode cable connections aboveground, if possible.
Repair buried connection in accordance with the original
coating manufacturer’s recommendations.
7/27/2019 DOT Pipeline Corrosion
http://slidepdf.com/reader/full/dot-pipeline-corrosion 25/31
ABC Chemical Complex 25
Corrosion Control & Monitoring
– Transformer/Rectifier Systems
» Install by a qualified electrician.
» Test rectifier at maximum design load to assure the
DC output meets the manufacturer’s specificationsincluding the maximum AC ripple.
» Calculate rectifier efficiency and record on the
rectifier data sheet.
» Verify the positive cable is attached to the anode bed and the negative cable is attached to the
protected structure or pipe.
7/27/2019 DOT Pipeline Corrosion
http://slidepdf.com/reader/full/dot-pipeline-corrosion 26/31
ABC Chemical Complex 26
Corrosion Control & Monitoring
» Miscellaneous Considerations
Inspect cables in terminal boxes to assure correct labels.
Verify test stations, bonding stations, and associated
hardware for cathodic protection service.
Contact owners/operators of foreign pipelines to enable
testing before and after new cathodic protection project
commissioning.
Record base readings on the new pipeline or structure
prior to cathodic protection system energizing. Record
potentials at all interference bonds and test stations.
Energize system in small current increments and record
potentials with each increase until protection is achieved.
Check bonding stations for interference problems.
File all commissioning data in the original equipment file.
7/27/2019 DOT Pipeline Corrosion
http://slidepdf.com/reader/full/dot-pipeline-corrosion 27/31
ABC Chemical Complex 27
Corrosion Control & Monitoring
– Quality Control Requirements, Internal Surface
» Inspect corrosion monitoring installations with the
services of a qualified Corrosion Technician.
» Take baseline data prior to pipeline commissioning.» Install lined pipelines per design.
» Repair lining of field joints as recommended.
» Install corrosion monitoring devices per design.
» Complete electrical installations with qualified
electricians.
» Document commissioning information as a part of
the original equipment file.
7/27/2019 DOT Pipeline Corrosion
http://slidepdf.com/reader/full/dot-pipeline-corrosion 28/31
ABC Chemical Complex 28
Corrosion Control & Monitoring
– Quality Control Requirements, Internal Surface
» Delay work initiation pending review of design
package by coating inspector.
» Protect coating material from weather.» Prepare surface for coating per manufacturer’s
recommendation immediately before coating
installation.
» Follow manufacturer’s recommendation for dew point and humidity.
7/27/2019 DOT Pipeline Corrosion
http://slidepdf.com/reader/full/dot-pipeline-corrosion 29/31
ABC Chemical Complex 29
Corrosion Control & Monitoring
OPERATIONS
– Perform cathodic protection surveys annually in
accordance with Company CP procedure.
– Monitor bonding and test stations annually.
– Read and record rectifier output monthly with
changes reported to the SR. Inspector for
evaluation and action. – Correct deficiencies in a timely manner.
7/27/2019 DOT Pipeline Corrosion
http://slidepdf.com/reader/full/dot-pipeline-corrosion 30/31
ABC Chemical Complex 30
Corrosion Control & Monitoring
MAINTENANCE
– Test rectifier stacks for proper performance
annually.
– Check anode bed resistance annually.
– Check insulating flanges and spools annually.
– Document all maintenance tests and add to the
equipment file.
C i C t l & M it i
7/27/2019 DOT Pipeline Corrosion
http://slidepdf.com/reader/full/dot-pipeline-corrosion 31/31
ABC Ch i l C l 31
Corrosion Control & Monitoring
Appendices
A - Coating Reference Index
B - Surface Preparation
C - Sample Data Sheets» Rectifier Data Sheet
» Anode Bed Data Sheet
» Galvanic Anode Data Sheet
» Potential Survey Data Sheet
Predesign Testing