Corrosion Training

1
Corrosion Training

• CP Designed Part 1
• Galvanic Anodes (current requirement testing),
  Insulators, Test stations, Coatings

2
Learning Over View

• Part One
• Current requirement design
• Galvanic anode design
• Insulators
• Coatings
• Test stations
• Coupons
• Part Two
• Rectified Systems, Solar panels
• Part Three
• AC Design

3
Objective of Class

• Understanding of design for COH and CKY with
  Corrosion
• Anodes (Galvanic)
• Insulators (types)
• Coatings (types)
• Test stations
• IR Coupons

4
Galvanic Anodes Types?

• Magnesium anodes are used for galvanic anodes in
  our system
• 17lb anode - remediation of WT pipelines
• 17lb anode - new steel coated pipe
• 9lb anode - bare main or service
• 3lb anode - bare customer service
• 1.5lb drive in anode company or customer
  metallic coated risers
• 1.0lb zinc serv-a-node

5
Galvanic Anodes When?

• Any time a metallic pipeline is exposed and the
  surface of the pipeline is disturbed and the pipe
  to soil readings are below -1.000 V CSE.
• Any time corrosion technician has indicated on
  corrosion recommendations
• CP mains reading below -.850 V CSE on a 2512 J.O.
  (annual monitoring)
• Cost and application evaluation performed for
  comparison of anodes vs. solar vs. rectified
  systems

6
Galvanic Anodes Connected?

• Thermite welded to the pipeline
• Thermite welds shall be 4 apart from each other
• Thermite welds shall be 6 away from an adjacent
  weld
• At any test station locations, connected by
  mechanical means by junction of the test station
  terminal

7
Galvanic Anodes Design?

• Current Requirement test
• Soil resistivity test
• Determine the output of a 17lb HP anode
• Number of anodes Icp/Ia
• Sunde theory

8
Galvanic Anode Design (new Coated
Steel Main)

• Surface Area of pipeline
• Diameter
• Length
• Coating Effectiveness
• Current Density
• Soil Resistivity

9
New Steel Pipe Calculations Number of anodes

• For an example
• First calculate the total surface area of 6 WT
  MP pipe at a length of 12,000 feet?
• Use the formula
• Total surface area Diameter x Length x

?
10
New Steel Pipe Calculations Number of anodes

• For an example
• First calculate the total surface area of 6 WT
  MP pipe at a length of 12,000 feet?

Keep in mind, a 6 inch diameter pipe is truly
6.625 inches
?
R
Length
Area
3.14 (6.625) 1.735 12,000 20,820 sq ft
12
Need to divide the diameter by 12 to convert to
feet
11
New Steel Pipe Calculations Number of anodes

• Next Calculate the total coating effectiveness
• The coating effectiveness will decide the total
  bare area that the CP current will be needed
• Keep in mind, the CP current protects only the
  holiday areas of the pipeline
• Calculate Coating Effectiveness
• 99.5 - Great
• 98.5 to 99.5 - Good
• 95 - Fair
• Less than 95 - Poor

12
New Steel Pipe Calculations Number of anodes

• Next Calculate the total coating effectiveness
• The coating effectiveness will decide the total
  bare area that the CP current will be needed
• Keep in mind, the CP current protects only the
  holiday areas of the pipeline
• Calculate Coating Effectiveness
• 99.5 - Great (Columbias Standard used)
• 98.5 to 99.5 - Good
• 95 - Fair
• Less than 95 - Poor

13
New Steel Pipe Calculations Number of anodes

• What is the total surface area?

14
New Steel Pipe Calculations Number of anodes

• What is the total surface area?
• 20,820 sq ft
• What is the total bare area of the pipeline?

15
New Steel Pipe Calculations Number of anodes

• What is the total surface area?
• 20,820 sq ft
• What is the total bare area of the pipeline?
• 104.1 sq ft

16
New Steel Pipe Calculations Number of anodes

• Next calculate the total amount of current
  requirement for CP of the pipeline
• Total bare area x current density ICP
• What is the bare area?
• 104.1 sqft
• What is the current density?

17
New Steel Pipe Calculations Number of anodes

• Current Density
• Is considered the square of the pipeline in which
  will conduct current
• Normally in the range 1 to 3 mA
• Sandy or Dry soil 3 mA
• Semi-dry soil 2 mA
• Wet soil 1 mA
• For current requirement calculations, we use a
  higher number for higher soil resistivity for the
  purpose of designing a higher amount of current
  requirement.

18
New Steel Pipe Calculations Number of anodes
What if the soil was very sandy and normally dry?

• Next calculate the total amount of current
  requirement for CP of the pipeline
• Total bare area x current density ICP
• 104.1 x 1mA 104.1 mAs

Current density
Bare Area of pipeline
Total amount of current requirement
19
New Steel Pipe Calculations Number of anodes

• Next calculate the total amount of current
  requirement for CP of the pipeline
• Total bare area x current density ICP
• 104.1 x 3mA 312.3 mAs

Current density
Bare Area of pipeline
Total amount of current requirement
Change current density to a higher number, such
as 3 mAs
20
New Steel Pipe Calculations Number of anodes

• Number of anodes Icp/Ia
• What is the total requirement for wet soil?
• Based on our calculations 104.1 mAs
• How many anodes needed?
• Have to calculate anode output next???

120,000 f y
?
21
New Steel Pipe Calculations Number of anodes
The top three numbers are given based anode
design, such as shape and weight of anode.
120,000 1 1.21
22.3 mA
6,500 ohms cm
Anode output is calculated
Input the soil resistivity to the bottom of the
equation
22
New Steel Pipe Calculations Number of anodes

• Now with the anode output and the total amount of
  current requirement is calculated,
• What is the total amount of anodes needed, if we
  decide to bank the anodes 10 feet apart?
• Number of anodes Icp/Ia
• 104.1 mA / 22.3 mA 4.6 (round to highest number
  5 anodes)
• 5 anodes
• Correct or not??????????

Need more anodes Not the correct design
23
Sunde Theory
Used for banking anodes
10 FT spacing
5 anodes
5 anodes at 10ft apart 4.19 anodes
24
Sunde Theory Calculation

• 5 anodes to be banked at 15 feet spacing.
• 4.43 22.3mA 98.8 mA
• The current requirement was at 104mA therefore 5
  anodes would not be enough.
• 6 anodes to be banked at 15 feet spacing.
• 5.22 22.3mA 116.4mA
• The current requirement was at 104mA therefore 6
  anodes would have enough output to meet cathodic
  protection.

25
New Steel Pipe Calculations Number of anodes

• Summary
• 6 WT Pipe _at_ 12,000 length
• 5 anodes, if distributed along the line
• 6 anodes, if banked at 10 feet apart
• Soil resistivity of 6500 ohms cm
• Current density of 1 mA
• Coating effectiveness of 99.5

26
Test Stations

• Above Ground
• Cott
• Large Fink
• Small Fink
• Gerome
• Tri-view flex
• B-T
• Curb box type
• COH and CKY Recommended use is the Tri-view
  flex for above ground use
• Gerome box for any continuity or interference
  bonds

27
Test Stations

• Two wires No. 12 Black
• New
• Carrier pipe
• Two wires No. 12 White
• Old/bare
• Casing

28
Test Stations

• Interference test station (bond)
• Two No. 8 wires (1-Company 1-Foreign)
• Two No. 12 wires black (company)
• Two No. 12 wires white (foreign)

29
Test Station - Spacing's

• Business 750 Feet
• Residential 1500 Feet
• Rural 6000 Feet
• P/P - 653-3

30
Coatings

• Coatings are our first line of defense against
  corrosion.
• Coatings are a high resistance barrier between
  the metallic structure and the surrounding
  electrolyte.
• A quality dielectric coating material can reduce
  costs in additional corrosion control materials
  such as sacrificial anodes or impressed current
  type cathodic protection systems.

31
Coatings

• Cathodic protection system design is based upon
  protecting the bare surface area of the
  buried/submerged metallic structure.
• Typically a well coated pipeline will be
  protected over 90 of its surface.
• In this case, only 10 of the pipeline surface
  will require cathodic protection current.

32
Coatings

• As an example
• 100 feet of 12 diameter pipe has 314 ft2 of
  surface area.
• A vertically installed 17 high potential
  magnesium anode in 5000 ?-cm soil has a current
  output of 30 mA.
• A design current density of 2 mA/ft2 results in a
  current requirement for the pipe of 628 mA.
• With 30 mA per anode, 21 anodes are required.
• However, if the pipe is 90 coated, then only 10
  or 31.4 ft2 is bare.
• At 2 mA/ft2 the current requirement is 62.8 mA.
• With 30 mA per anode, only 3 anodes are required!
• This shows the importance of having a quality
  coating.

33
Coatings

• Holiday Testing (Jeeping)
• Test process which the operator can identify
  holidays (imperfections) in the coating
• Involves a high voltage power source
• Instruments can be adjusted to apply the proper
  voltage across the coating
• Different thickness of coating requires
  different settings
• Electrode is passed over the coating surface
• If the coating resistance is low or a holiday is
  present, an audio signal is heard due to an
  electrical discharge from the electrode onto the
  pipe surface
• Repair of the coating is made

34
Coatings Jeep Settings
Fusion Bonded Epoxy
Powercrete
Extruded
35
Coatings Jeep Settings
Some common Jeep voltage settings for common
coatings
36
Coatings Jeep settings

• You maybe asked to QA or verify the coating
  thickness base on the jeep process
• Check the coating thickness
• DFT
• Check the voltage setting of the Jeep
• Verify, the contractor or crew is creating a
  holiday to verify the setting

37
Coatings Jeep Process
38
Coatings Jeep Process
39
Coatings

• Three common types mostly used in the gas
  industry
• Extruded
• Fusion bonded epoxy (FBE)
• Powercrete

40
Coatings

• Extruded
• High density polyethylene
• Can be supplied in different thickness up to 60
  mils
• Asphalt or rubber butyl adhesive
• Normal thickness is in the range of 10 to 15 mils
• Used primarily for direct bury application
• Girth welds normally coated with cold-applied
  tapes

41
Coatings - Extruded
42
Coatings - Extruded

• Direct Bury -
• X-Tech II COH CKY practice for direct bury
  design, 1st choice
• 70 mill application
• Two layers of 30 mills of polyethylene coating
• 10 mills of butyl rubber mastic

43
Coatings - Extruded

• Design for AC and/or DC interference currents
• Use only Extruded X-TECH II coating systems

44
Coatings - FBE

• Fusion Bonded Epoxy
• Surface preparation includes sand blasting
• To clean the surface and form anchor patterns for
  the coating to adhere or bond to the pipe surface
• Surface is acid washed to remove salt deposits
• Surface is washed with dionized water
• Pipe surface is heated to 500 degrees or hotter
• Epoxy powders are electro statically charged and
  sprayed onto the hot surface
• The powders melt to a liquid form and fuse to the
  pipe surface forming a hard shell
• The applied coating normally cures within 90
  seconds and then is blasted with cool water in
  order to facilitate handling

45
Coatings - FBE

• FBE
• 12 15 mills of FBE first layer
• 20 mills of FBE second layer
• Total of 32 to 35 mills coating
• COH CKY practice only use dual coats, never
  single layer systems, 2nd choice for direct bury

46
Coatings Powercrete

• Epoxy base Polymer Concrete
• The pipe is coated with an FBE normally with a
  thickness of 12 to 15 mils
• The FBE is then coated with the polymer concrete
  coating (Powercrete) 20 mills

47
Coatings - Powercrete

• Can be applied in the field
• Each pass applies approx. 20 mils thickness
• Max 125 mils
• Perfect for directional boring
• COH and CKY recommendation for directional
  boring design
• Use for above ground design with a polyurethane
  outer coat

48
Coatings - Powercrete

• COH CKY practice a minimum of 50 mils for
  above ground application
• COH CKY practice a minimum of 50 mils for
  directional boring application
• COH CKY practice a minimum of 70 mils for
  rocky directional boring applications

49
Coatings Girth Welds

• Girth Welds
• FBE and Powercrete coating applications
• COH CKY practice two part liquid epoxy system
• Protal 7200 temps at or above 50 degrees
• Protal 7125 temps below 50 degrees
• R95 temps at or above 50 degrees back up
  coating
• Surface will need to be sand blasted to a Nace 1
  anchor pattern
• The two parts are mixed
• Epoxy resin
• Epoxy hardener
• Coat the surface of the girth weld according to
  manufactures recommended wet film thickness
• Use the same material on the holiday areas as
  well

50
Coatings Girth Welds

• Girth Welds
• Extruded Coatings X-Tech II
• Acceptable methods
• Polyken 936
• Tape coat H35
• Petrolatum Tape
• Utility tape (PVC) on new steel applications to
  be used
• S105 paste recommended, especially in cold
  climates

51
Coatings Thermite welds

• No mastic..
• Preference especially for vacuum systems
• Acceptable methods
• Petrolatum products
• Profile mastic petrolatum Denso product (bird
  seed)
• Top coat with the Denso Color Tape petrolatum
  Denso product
• Protal 7200 cartridge
• Mix product on cardboard
• Dip brush and paint onto surface
• Cover with Trenton wax paper to prevent any
  damage due to debri of dirt
• Trenton patch kits (watch cost higher dollar)

52
Coatings Transmission and/or Directional boring
Applications

• Corrosion FLL shall be contacted
• Corrosion department will inspect the pipeline at
  the coating Mill using the recommended Hold
  points

53
Coatings - Rock shield
In a rocky back filled situation, one should
apply an outer protected shield for your pipeline
coatings. Note On CP systems, use the mesh rock
shield only.. As to not cause cathodic shielding
with the solids
54
Insulators - Types

• Kero-Test Monolithic Weld-in
• Bangs Flanged Weld-in
• Dresser bolted coupling
• Compression
• Unions
• Flanges

55
Insulators When?

• Tying new pipe to old pipe (coated)
• Tying coated pipe to bare pipe
• Domestic, large volume and GM settings
• Separate house lines from company lines
• Casing from carrier pipe
• Pipe from supports
• Bridges
• MR settings
• Break a large circuit to smaller units for easier
  troubleshooting and management
• Separate shorts with foreign lines
• River crossings

56
Insulators - Tying new and old existing Coated
Pipelines

• Recommended for use in galvanic systems due to
  limited driving potential of the magnesium anodes
• Cost comparison
• Evaluate the cost for an insulator to be
  installed
• For example, if one insulator to separate a 100
  section of new coated metallic pipe from an
  existing CP coated metallic anode system (older),
  will cost in the range 4,800.00 x 2 9,600.00
  then it may not be cost effective to make this
  recommendation.
• Purpose to prevent a galvanic cell to be
  created due to the potential difference with the
  new coated pipeline and the old coated systems
• For an example, the new coated system can have a
  high negative potential in reference to the old
  coated bare main.

57
Insulators - Tying new and old existing Coated
Pipelines

• Test station installed at location
• Two black wires - 12 (New)
• Two white wires - 12 (old)
• Two no. 8 wires
• One wire connected to the New
• One wire connected to the old
• Bond in the test station box,
• if rectified system
• If anode system and want to cathodically protect
  as a single circuit

58
Insulators - Tying new and old existing Coated
Pipelines

• If not bonded in the test station box, then
  create two facilities on WMS and two test point
  sheets

59
Insulators - Tying new and old existing Coated
Pipelines

• Recommended spacing's of insulators
• Business 1500 feet
• Residential 3000 feet
• Rural 12000 feet

60
Insulators - Tying to Bare Pipe

• All coated systems tying to bare systems are to
  be insulated off
• Test station installed at location
• Verification to be made on annual monitoring
• Trouble shooting purpose
• Two white wires on the bare pipe
• Two black wires on the coated pipe

61
Insulator Weld - In
COH CKY practice always use weld-in
insulators and only the Zunt monolithic for
buried pipelines
Monolithic weld end insulators are an excellent
choice for high pressure systems where pull out
may be an issue with other insulated coupling
devices.
No field assembly required or bolts,washers or
sleeves that could cause an electrical short.
62
Insulators - Meter settings - Types

• Insulated valves
• Insulated Unions
• Insulated Meter bars
• Insulated Swivels
• Insulated Flanges
• Design purpose
• Domestic size meters
• Insulated Valves
• Large volume, or GMB accounts
• Insulated Unions
• Insulated flanges

63
Insulators MR Station

• Insulated in a structure
• Must have a zinc grounding cell installed (DOT
  and procedure requirement)
• Insulated at flange _at_ outlet of valves
• Outlet valve
• If need to replace flange insulators, on lower
  pressure end
• Bypass valve
• All control lines need to have insulated unions

64
Insulators MR Station
A high dielectric strength material is used
fiber glass or a plastic material to prevent a
metallic connection between the two flange faces.
The bolt acts as a bypass if not insulated
properly.
65
Insulator Casing and Carrier Pipe

• Casing isolation two primary functions
• Prevent an electrolyte from entering the casing
  and creating a galvanic corrosion cell.
• Prevent metallic contact between the carrier pipe
  and casing pipe.
• Casing isolation may remove up to two of the four
  parts of a corrosion cell.

66
Insulators Casing Carrier Pipe

• Casing isolation Three primary tools used
• Casing filler
• High dielectric material (high resistance) to
  displace the electrolyte within the casing
• Casing spacers
• Insulating material to prevent metallic contact
  between the casing pipe and the carrier pipe
• Casing seals
• Physical seal used to seal the ends of the casing
  in order to prevent an electrolyte from entering
  the casing

67
Insulator Casing Carrier Pipe Casing Filling

• Petrolatum based material that has a high
  dielectric strength.
• Displaces the surrounding electrolyte in the
  casing around the carrier pipe.
• Prevents water from entering the casing and
  displaces the existing water.
• Environmentally safe non-hazardous.

68
Insulator Casing Carrier Pipe Casing Filling
Casing filler can be installed hot or cold.
There is treatment for casings already filled
with water.
Pictures -Courtesy of Trenton co.
69
Insulator Casing Carrier Pipe - Spacers
Spacers are made from a dielectric material, hard
polymer (plastic). A spacers primary function is
to prevent the metallic contact between the
casing pipe and the carrier pipe.
70
Insulators Casing and Carrier Pipe Link Seals
Rubber boots
Seals the ends of the casing around the carrier
pipe. Keeps the casing filler inside the
casing. Prevents water or other elements from
entering the casing and creating a galvanic cell.
71
Pipe Supports

• Coated metallic pipe shall be isolated from any
  bridge structure
• Fiber board
• Glass mesh insulated bridge supports

72
Pipe Supports

• Coated metallic pipelines shall be insulated from
  any supports at MR settings
• Existing pipe may need to be lifted off the
  support area to be insulated properly

73
Insulator FRPs
FRPs Fiberglass Reinforced Plastic
74
Insulator FRPs

• Primary function of FRPs
• To prevent an electrical connection between the
  structure intended for cathodic protection and
  foreign metallic structures.
• Separates the anode from the cathode by
  electrically isolating the two structures.
• Reduces the required amount of corrosion
  materials to be used.

75
Insulator FRPs
There are a variety of types of FRPs.
Flat FRPs are a practical way of physically
separating two buried structures especially in an
excavation situation.
76
Insulator FRPs
Some FRPs are attached to the structure with an
epoxy adhesive sealant, this helps mitigate
crevice corrosion from taking place between the
FRP and the pipeline.
Another type of installation involves applying a
petrolatum tape material between the FRP and the
pipeline to mitigate crevice corrosion.
77
Insulator FRPs
FRPs are an excellent material to be used on
bridge crossings or other aboveground pipe
supports.
Courtesy of Glass mesh
78
IR Coupons
Two no. 12 stranded wires.

• Benefits of using coupons
• Obtain IR drop free potentials
• Especially on systems that the current source can
  not be interrupted.
• AC measurements such as AC current density
  calculations.

Surface area 1.34 in2
79
IR Coupons
The coupon needs to be of the same material as
the pipeline in order to represent it accurately.
80
IR Coupons
Need to have the coupon close to the pipeline
(normally within 4 to 12, buried in the same
native soil as the pipeline.
81
IR Coupons
Best practice is to place the coupon about mid
way of the pipeline on the side.
82
IR Coupons
Connect the coupon in the test station by bonding
to the pipeline. The coupon will receive the
same cathodic protection current as the pipeline.
83
IR Coupons
The coupon represents a holiday area of the
pipeline. The cathodic protection system (CP)
protects the holiday areas of the pipeline, by
bonding the coupon to the pipeline, the CP will
polarize the coupon as well. We can remove the
IR drop and find the true polarization on the
pipeline by separating the connections and taking
an instant-off structure-to-electrolyte potential
measurement.
84
IR Coupons
Test Station
Bond or Switch
The blue wires identify the lead wires used to
electrically bond the coupon to the pipe.
V
Connect the voltmeter to the non-current carrying
lead wire from the coupon.
Coated pipeline
Coupon
85
IR Coupon - Measurements

• Coupon measurements
• Allow the coupon to polarize by electrically
  bonding the coupon to the structure in the test
  station.
• Disconnect or interrupt the coupon from the
  structure.
• Obtain structure-to-electrolyte potential
  measurements of the coupon, current applied and
  momentarily interrupted.
• The potential readings will be IR-drop free and
  will represent the pipelines IR-drop free
  potential readings.

86
Material Summary

• Test stations
• Above ground
• Tri-view Flex
• Gerome for multiple wire connections such as
  bonds
• Anodes
• Connected in the test station box
• Get soil resistivity in designing
• Use anode calculation spread sheet
• 17lb CP remediation and new coated steel
  pipeline
• 9lb Bare pipe leak repairs
• 3lb customer service lines
• 1.5lb drive in anodes isolated metallic
  coated risers

87
Material Summary

• Insulators
• Below ground Zunt Monolithic Weld-in
• Above ground MR flange insulated kits
• Insulation made inside a building (MR)
• Zinc grounding cell installed
• Always place a test station at insulation
• Always insulate casings and fill

88
Material Summary

• Coatings
• Powercrete 50 mil directional boring
• Powercrete 70 mil rocky directional boring
• Powercrete 50 mil bridge crossings and/or any
  exposures
• 10 mils of polyurethane top coat
• FBE only use dual coat applications of 32 to 35
  mils
• Extruded used primarily as direct bury
  applications
• Use for stray current surroundings
• AC or DC
• All coating applications transmission class
• Inspected at the coating mill

89
Any Questions?
Thank You