3lpe

Pipe Coating and Failure Modes of Mainline & Field Joint Coatings – Pictorial Learning's

Michael Surkein – Senior Corrosion and Materials Consultant&

Jeff Didas – Corrosion Specialist ExxonMobil Development Company

Houston, Texas

OGP Coatings Committee – London

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Pipe Coatings

• Pipe coating purpose

• Typical selection• Mainline & field joint

• Why coatings fail ?

• What is the life of a coating ?

• Pictorial experiences

• Lessons learned

• Conclusions

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Pipe Coating Purpose• Prevent corrosion of pipe steel

• Reduce cathodic protection current demand

• Easy to apply pipe coating

• Availability

• Performance• Handling• Cathodic disbondment

• Long life

• Simple field joint

• EM Global Practices References• API & NACE• ISO• AFNOR• ASTM• CSA

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Typical - Pipe Coatings of Choice

Selected from EM Global PracticesMain Line Pipe Coatings • Fusion Bonded Epoxy (FBE)

• Mostly in North America• Single or dual layer up to 95 C (200 F) • Dual layer for HDD’s

• 3 Layer Polyethylene (3LPE) - up to 80 C (175 F)• Common outside US

• 3 Layer Polypropylene (3LPP) - up to 110 C (230 F)• More common outside US

Field Joint Coatings• FBE, 3LPE, 3LPP• Liquid

• Epoxy • Epoxy Urethane• Tar Urethane

• No heat shrink sleeves

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Field Joint Selection

Mainline Pipe Coating Preferred Field Joint

Alternate Field Joint

FBE - Onshore FBE Liquid epoxy or epoxy urethaneLiquid urethane

FBE - Offshore FBE

3LPE - Onshore 3LPE Liquid urethaneLiquid epoxy urethane

3LPE - Offshore 3LPE FBE + Solid Polyurethane

3LPP - Onshore 3LPP Epoxy novalocFused polypropylene (PP) sheet under evaluation

3LPP - Offshore 3LPP (injection molded)

Flame spray PP & new technology under evaluation

Infill Materials - Offshore

• Polyurethane foam

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Pipe End Detail

1)Coating cut-back shall be 125 mm, 30 degree to 40 degree chamfer, and a 50 mm fusion bonded epoxy (FBE) tail; +10 mm or −20 mm. Figure 1: Pipe End Cross Section

Pipe Wall

30°-40° Chamfer of Outer Layers125 mm Cut-Back

50 mm FBE Tail

PP or PE Outer LayerAdhesive

FBE Primer

Coating cut-back shall be 125 mm, 30 degree to 40 degree chamfer, and a 50 mm fusion bonded epoxy (FBE) tail; +10 mm or −20 mm.

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Field Joint Coatings• Quality & Integrity

• Typically the weak point in a pipe coating system• Aligning field joint coating requirements with mill

applied coatings• Cutback configuration and integrity is

important• Multi-layer systems are often challenging

• Employing skilled field joint coating contractors is critical.

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Why Coatings Fail ?

• Age

• Selection

• Application

Which is most important?

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What is the Life of a Coating?

• Determined by design

• Determined by use

• Determined by selection

• Determined by application

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Is Handling of Coated Pipe Important?

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Do Pipe Coatings Like Sunlight?

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Do Pipe Coatings Like Sunlight?

• Coating thickness• Impacted by UV • Epoxy will chalk

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Coating Damage?

• Long weld seam

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Coating End Bonding

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Coating End Bonding

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Handling Damage

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Storage Protection

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Handling Damage

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Application Quality

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Application Quality

• Cathodic Disbondment

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Cathodic Disbondment

• Cathodic disbondment testing• International standards• Company standards• Third party labs

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Field Coating Repair

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Coating Blistering

• Overheating• Surface contamination

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Coating Bendability

• Field bends• Coating qualification• International standards• Company standards• Testing at lowest

installation temperature

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Coating Over Thickness

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Coating Over Thickness

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Coating Poor Adhesion

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Wrinkling

• Poor adhesion• Temperature• Soil stress• UV degradation

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Wrinkling

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Wrinkling

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Wrinkling

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Thickness & Curing

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• Curing• Over thickness• Overheating• Heating too fast

Field Joint Coating Quality

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Cracking

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Cracking

• Over thickness• Curing• Bendability• Qualification

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Weld Surface Preparation

• Difficulty abrasive blasting rough welds

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Final Coating - Visual

• Is final visual inspection suitable to determine field joint coating quality?

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• Was surface preparation suitable?• Adhesion seem questionable.

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Heat Shrink Sleeve Field Joint

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Field Joint Coating & Repair

Heat Shrink Sleeve

Coating Repairs

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Tape Coating – Poor Adhesion

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Coating Experts???

Do Too Many Cooks Spoil the

Meal???

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Pipeline Coating Testing

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Lessons Learned• Select coatings by service

conditions• Current and future• Shipment and storage

• Do not select coatings by price only

• Use a quality specification• Include detailed requirements• Include qualifications• Conduct preproduction meeting

• Use a qualified applicator• Pre-qualify

• Use a qualified and experienced inspector

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Coating Manufacturer

“We have the very best materials – nosecond-best here!”

Coating applicator

“We’re the best and the greatest coatingapplicators – no improper coating jobs!”

Customer… is left holding the bag when the coating

fails

Three Players Involved

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Wrap Up

• Any more discussion?

• Questions?

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Contact Information

Michael Surkein

ExxonMobil Development Company

12450 Greenspoint Drive

Houston, TX 77060

281-654-4821

[email protected]

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