Chapter 18 - Pipeline Mainline And Field Joint Coatings Flashcards
Where is the majority of the pipe for mainline coated?
They will have been coated in coating facilities or plants the. Shipped to the site.
Typical plant-applied or mainline coatings include?
2-layer PE 3-layer PE Fusion bonded epoxy Tapes Coal tar enamel Asphalt Insulated Concrete
How can polyethylene (PE) be extruded?
Side extrusion for large diameter pipe
Crosshead extrusion
What are the common characteristics of FBE?
Typically green or red and looks like a painted finish
May be a single layer or a two-layer “dual -powder”
DFT from 250 and 500 microns (10 to 20 mils)
What is included in the FBE application process?
Preheating the pipe
Grit or shot blast the area to NACE #2 / SSPC-SP10
Optional-pre-treat the area twitch an acid bath
Heat the pipe to the specified temperature
Apply the FBE coating
Curing the FBE coating application
Quench the coating in a fresh water bath
Stencil
What are the advantages of coal tar enamel pipeline coating?
Ease of application
Long life in some environments
What are some of the disadvantages of coal tar enamel pipeline coatings?
Subject to corrosion and damage from soil stress
Environmental and exposure concerns
Use of coal tar is regulated in some locations
What is the general application process for coal tar enamel?
Prime the pipe
Apply coal tar enamel dope
Wrap the application with glass fiber mat
Apply a second layer of CTE dope
Wrap the application with a second layer of glass fiber mat
Apply an outer wrap of coal-tar impregnated glass fiber felt
Cool the application
What are some concrete coating characteristics?
Used in conjunction with other coating such as FBE
used to reduce buoyancy so pipe will sink
Can be applied in many thickness
Can be applied to any diameter of pipe
Pipeline coating field joints include?
Heat shrink sleeves Insulation half shells Field foam Liquid epoxies Cold applied tapes Hot applied tapes FBE field joints Petroleum (wax) tapes
What are the non-destructive tests for heat shrink sleeves?
Visual inspection
Physical inspection
Holiday detection
What are the destructive tests for heat shrink sleeves?
Holiday detection ( If the voltage set too high) Peel test. A 25 mm (1”) wide strip cut, pulled from the pipe
What materials can be used to repair FBE?
Epoxy FBE melt sticks
Liquid epoxy
Repair patches
Heat shrink sleeves
Construction materials may include, but are not limited to the following?
Steel, aluminum, stainless steel and plastic.
