Transcript Coatings – Directional Boring

Coatings – Directional Boring
Tim Jenkins
Coatings – Directional Boring
Design Considerations (data collection)
 Contributed coating failures
 Pre-Operation steps
 Post-Operation steps
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Design – Directional Boring
Coatings
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Data Collection for coating selection
 Surrounding Environment
 Soil composite
 Location
 Foreign lines –
• Other pipelines
• AC Transmission towers
 Timeframe
Design – Directional Boring
Coatings
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Powercrete –
 12 to 15 mils of FBE (Fusion bonded Epoxy)
3M 6233
 Concrete polymer base outer coat 20mils per
application, two applications normally used
 Typically 55 to 60 mils coating thickness
FBE – Dual coat
 12 to 15 mils of 3M 6233
 20 mils of a Dual coat application of 3M 6352
 Typically 35 mils total coating thickness
Design – Directional Boring
Coatings
Time frame considerations –
 Powercrete – hand applied, 4 joints per 2
hours can be coated
 FBE – Dual coat – assembly line, 3000 feet
in three hours
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Design – Directional Boring
Coatings
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Durability –
Powercrete – UV protected, more abrasive
resistance in comparison to the FBE dual coat
Recommended practice –
 Abrasive environment use the Powercrete
application,
 In well known normal soil application, FBE
dual coat acceptable and probably more cost
effective
Design – Directional Boring
Coatings
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Coatings Case history - Failures
The most popular coating failure  Cathodic Shielding
 Rock formation
• Pipe wedge next to a rock formation at
the point of coating holiday
 Disbondment coating
• Coating becomes disbondment from the
surface of the pipe, but shields the CP
from the surface of the metallic structure
exposed under the coating
Cathodic Shielding - Rock
Cathodic Shielding – Coating
Disbondment
Design – Directional Boring
Coatings
Coatings Case history - Failures
 Thickness of coating application –
 The thicker of the coating, less durable,
more brittle
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Harlem RD Bore – Coating
Failure
Design – Directional Boring
Coatings
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Coatings Case history - Failures
Powercrete –
 Flexibility – Degrees per pipe diameter
 1.4° for 35 mils
 .75° for 55 mils
FBE – Dual Coat –
 Flexibility – Degrees per pipe diameter
 2.8° for 35 mils
Design – Directional Boring
Coatings
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Coatings Case history – Failures
FBE Dual coat more flexible than
Powercrete
But,,,
 Powercrete more impact resistance than
FBE
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Design – Directional Boring
Coatings
Powercrete application adhesive bond to the
FBE, and the dual coat 3M will result of
complete pull out of coating application
from the metal surface due to, coating
flexibility angle being too great
 In a normal pulling process, coating will be
disbondment by layers and normally does
not result in total removal
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Design – Directional Boring
Coatings
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Girth Welds –
 Two part Liquid Epoxy used
 Protal 7200 - 50° or greater
 Protal 7125 - 50° or less
 R95 – Powercrete J (new)
 Pipe Preparation –
 Sand blasting – NACE 2 or SSPC-SP10
Northern Loop – Hoover Bore
Girth Welds
Design – Directional Boring
Coatings
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Transmission Class pipeline
ECDA
 Pipe thickness design
 %SYMS
ICDA
 Internal Coupons
 Probes
 Inclination angle consideration
 Do not get greater than the Critical Inclination angle
 Inline Inspection – smart pigging
Pre-Operation Steps
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Columbia Gas needs to inspect all coated pipe line
at the coating mill before the pipe is coated
Corrosion Technicians are being trained, KTA
certified
Communication should be placed to Corrosion
FLL by Supply chain
Need to consider cost of technician or coating
inspector to work order budget
Corrosion Department Inspecting
Powercrete application for
Maumee River Crossing
Pre-Operation Steps
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Pipe Inspected in the field by the corrosion
department
 Determine any coating defects due to shipment
Pipe and girth welds coatings inspected in the field
by the corrosion technicians
 Dew point readings
 Pipe Temperature
 Chloride check
 DFT
 WFT
 Observe Jeeping process – recommend voltage
setting
Post Operation Steps
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Survey – Coating and CP
 CP –
 CIS – Close Interval survey
 External Coupons used
 Coating
 DCVG – Direct Current Voltage Gradient
 ACVG – PCM – Alternate Current Voltage
Gradient
 Cost of survey new steel pipe by corrosion
department should be considered on the work
order budget