Pipeline mainline and field joint coatings Flashcards
Construction materials may include but not be limited to?
Steel
Aluminium
Stainless
Plastic
The majority of the pipes coated at a coatings facility/plant and then shipped to site are called_______
Mainline pipes
Typical plant applied or mainline coatings include?
2-layer PE 3-Layer PE Fusion bonded epoxy Tapes Coal tar enamel Asphalt Insulated Concrete
Polyethelene (PE) can be extruded by?
Side extrusion for large diameter pipe
Crosshead extrusion
Common characteristics of FBE include?
Typically green or red and looks like a ‘painted’ finish
May be a single layer or two-layer ‘dual powder’
DFT from 250 and 500 microns (10 to 20 mils)
The FBE application process includes
Preheating the pipe
Grit or shotblast the area to NACE 2/SSPC-SP10
Optional - Pre-treat the area with 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
The advantages of coal tar enamel pipeline coatings include?
Ease of application
Long life in some environments
The disadvantages of coal tar enamel pipeline coatings include?
Subject to corrosion and damage from soil stress
Environmental and exposure concerns
Use of coal tar is regulated in some locations
The general application process for coal tar enamel includes?
Prime the pipe
Apply coal tar enamel dope
Wrap the application with glass fibre mat
Apply a second layer of CTE dope
Wrap the application with a second layer of glass fibre mat
Apply an outer wrap of coal tar impregnated glass fibre felt
Cool the application
Concrete coating characteristics include?
Used in conjunction with other coating such as FBE
Used to reduce buoyancy so pipe will sink
Can be applied in many thicknesses
Can be applied to any diameter of pipe
Pipeline coatings field joints include?
Heat shrink sleeves Insulation half shells Field foam Liquid epoxies Cold applied tapes Hot applied tapes FBE field joints Petrolatum (wax) tapes
Non-destructive tests for heat shrink sleeves include?
Visual inspection
Physical inspection
Holiday detection
Destructive tests for heat shrink sleeves include?
Holiday detection (if the voltage is set too high) Peel test. A 25mm (1in.) wide strip cut, pulled from the pipe
The following materials can be used to repair FBE
Epoxy FBE melt sticks
Liquid epoxy
Repair patches
Heat shrink sleeves
