Pipeline Mainline & Field Joint Coatings Flashcards
What are the three main products transported by pipelines?
- Oil
- Gas
- Water
What are the different type of pipelines?
- Gathering
- Midstream
- Transmission
- Distribution
What is a gathering pipeline?
Collects raw gas from wells and ships to plants for processing
What is a midstream pipeline?
Ships processed gas from gas plants to storage facilities
What is a transmission pipeline?
Ships gas from storage facilities to markets across the country
What is a distribution pipeline?
Collects gas from the transmission system to distribute gas to end users
What are three things you need to know to stop a pipeline from rusting too much?
- Corrosion/environment
- Coatings
- Cathodic protection
To apply field joint coatings properly you will need to know:
- What mainline coating was applied to the pipeline
- What field joint coating is to be applied
- How to recognize the mainline coating visually
The most common two-layer polyethylene (PE) coating is what color?
Typically yellow
Two-layer PE is the most popular coating used for nominal pipe sizes 2” to 16”.
True or false?
True
What is the base layer of two-layer PE?
Usually black mastic (asphalt and rubber) adhesive applied directly to steel substrate
Two-layer PE is rated for a pipeline operating temperature up to how many degrees?
140°F
What are the characteristics of three-layer PE?
- Looks like 2LPE
- Includes a layer of FBE (fusion bond epoxy) directly on the steel
- Intermediate layer is an adhesive; usually not visible
List steps of three-layer PE application.
- Preheat pipe (if required)
- Epoxy/FBE application
- Application of co-polymer adhesive layer
- Application of PE (side or cross-head extrusion)
What color(s) are fusion bonded epoxy (FBE)?
Typically green or red and looks like a painted finish
How many layers does FBE have?
May be a single layer or a two-layer “dual-powder”
What is the DFT range for FBE?
DFT from 10 to 20 mils
Pipeline Maintline & Field Joint Coatings
Where can tapes be used?
Can be used as a standalone coating on water lines or as part of an insulation system
What are some advantages of coal tar enamel?
- Ease of application
- Long life in some environments
What are some disadvantages of coal tar enamel?
- Subject to corrosion and damage from soil stress
- Environmental and exposure concerns
- Use of coal tar is regulated in some locations
Pipeline Mainline & Field Joint Coatings
Describe heat shrink sleeves and basic process
- Have crocess-linked polyethylene backing and a heat-activated adhesive
- Heat shrinks the outer sleeve
- Preheated substrate melts inner adhesive
- Adhesive is forced into the surface
Pipeline Mainline & Field Joint Coatings
What are the two types of tests that can be done on shrink sleeves
- Non-destructive
- Destructive
Pipeline Mainline & Field Joint Coatings
What non-destructive tests that can be done on heat shrink sleeves?
- Visual inspection
- Physical inspection
- Holiday destection (can be destructive if voltage is set too high)
Pipeline Mainline & Field Joint Coatings
What destructive tests can be done on heat shrink sleeves?
Peel test (NACE TM 21240)
Pipeline Mainline & Field Joint Coatings
Describe the peel test on heat shrink sleeves.
(NACE TM 21240): A 1” wide strip cut, pulled from pipe. Look for the mode of failure as follows:
- Cohesive failure in the adhesive PASS
- Adhesive failure to the substrate FAIL
- Adhesive failure to the backing PASS
Describe insulation half shells
- Minimum density polyurethane
- Available in pipe diameters 1” to 16”
- Variable thicknesses are available
- Field repair kits are available from various manufacturers
Pipeline Mainline & Field Joint Coatings
Liquid epoxies look like FBE.
True or false?
True
Where would liquid epoxies be used on pipelines
Used for short sections of pipe, bends, and configurations
What would the DFT range be for liquid epoxies on pipelines be?
DFT from 10 mils to 60 mils, normally nominal thickness of 20 mils
Pipeline Mainline & Field Joint Coatings
What are the two types of tests that can be done on cold applied tapes?
- Non-destructive
- Destructive
What non-destructive tests that can be done on cold applied tapes?
- Visual inspection
- Physical inspection
- Holiday destection
What destructive tests can be done on cold applied tapes?
Peel test
Surface preparation is the same for hot applied tapes as heat shrink sleeves.
True or false?
True
What are the two ways to tell if hot applied coating tape is fully shrunk?
- Tape will shrink down tightly to the pipe surface
- Adhesive flows out from the edges of the hot tape
What color(s) are FBE field joints?
Typically green or red
What materials can be used to repair FBE?
- Epoxy FBE melt sticks
- Liquid epoxy
- Repair patches
- Heat shrink sleeves
What is petrolatum (wax) tape?
- Composed of synthetic fabric, filled with petrolatum compound, filler and anti-corrosion agents
- Creates solid water barrier
- Excellent strength/very good abrasion resistance
- Good resistance to acids, alkalis, salts, and bacteria
Where would petrolatum (wax) tape be used?
- Pipeline joints and bends
- Flanges
- Valves
What are some mainline coating repair products?
- Mastic fillers
- Repair patches
- Melt sticks
Linings are applied to the inside of pipelines in order to ________.
A. Provide a weight coating
B. Maintain product purity
C. Reduce resistance to flow
D. Minimize cathodic protection cost
B. Maintain product purity
C. Reduce resistance to flow
All 2-layer polyethylene (2LPE) applies directly to the steel with a ___________.
A. Black mastic (asphalt and rubber) adhesive applied beneath the polyethylene (PE)
B. Base layer of asphalt cutback applied beneath the polyethylene (PE)
C. FBE primer layer, with a co-polymer tie coat applied beneath the polyethylene (PE)
D. Co-polymer adhesive primer applied under the polyethylene
D. Co-polymer adhesive primer applied under the polyethylene
You have taken an assignment as the coating inspector on a pipeline being installed in your locality. The mainline section of the pipe have already been coated in the fabrication facility. To ensure field join coatings are properly applied you will need to know the following?
A. What mainline coating was originally applied
B. What field joint coating was specified
C. The batch numbers of the mainline coating
D. The steels chemical make up (mill certification)
A. What mainline coating was originally applied
B. What field joint coating was specified
Which coating is in limited use due to environmental and exposure concerns?
A. 2-layer high density polyethylene (2LPE)
B. Fusion bonded epoxy
C. Coal tar epoxy
D. Petrolatum Wax Tape
C. Coal tar epoxy
What is the most common application method for Petrolatum (wax) tape on a pipeline?
A. Hand
B. Roller
C. Spray
D. Mitt
A. Hand
Inspection considerations for heat-shrink sleeves include which of the following?
A. Ensure the sleeve is in full contact with the pipe
B. Ensure there is adhesive flow-out beyond the sleeve edge
C. Holiday detection at proper voltage
D. Ensure that entrapped air present to insulate the pipe
A. Ensure the sleeve is in full contact with the pipe
B. Ensure there is adhesive flow-out beyond the sleeve edge
C. Holiday detection at proper voltage
Liquid applied epoxy coatings for pipeline typically require that you ensure which quality control steps?
A. Pre-cleaning surface to remove contaminants
B. Surface preparation conforms to the specification
C. Ensure mixing per the manufacturer’s
D. Ensure the product is applied with plural component spray
A. Pre-cleaning surface to remove contaminants
B. Surface preparation conforms to the specification
C. Ensure mixing per the manufacturer’s
You are the coating inspector on a pipeline project where field applied foam will be used for insulation. Which of the following are quality concerns regarding the cutback?
A. Squared cutback edges
B. Cutting into the anti-corrosion coating
C. Cut is curved properly
D. Minimum overlap at joints
A. Squared cutback edges
D. Minimum overlap at joints
