Abstract a Land Ke Hr

7/29/2019 Abstract a Land Ke Hr

http://slidepdf.com/reader/full/abstract-a-land-ke-hr 1/18

1

Fusion-Bonded Epoxy (FBE) and Dual-Layer FBE Materials

Provide Enhanced Performance for Pipeline Installation

By: J. Alan Kehr, Martin Rau, and Emran Siddiqui; 3M Company

SUMMARY

Fusion Bonded Epoxy (FBE) and 3 Layer Polyolefin (3LPO) are the most commonly used

pipeline coatings in the world. Over the last few years, dual Layer FBE (DLFBE) coatings

have seen more use because of combining properties of a coating that is non-shielding to

cathodic protection and the low-cost economics of FBE with damage resistance approaching

that of 3 Layer Polypropylene (3LPP) and 3 Layer Polyethylene (3LPE).

FBE BASED COATING SYSTEMS

FBE Single Layer. Since first introduced in 1960, single-layer FBE has proven its capability

as a pipeline coating and is now the most commonly used pipeline coating in North America.

It not only has the performance characteristics important to the application and construction

processes, but also has proven performance in underground and undersea service over a long

period of time. It has proven effective for line pipe, girthwelds, fittings, and bends. When

used at a greater thickness, it has worked effectively with weight concrete and directional-

bore installations.

FBE Two Layer. Utilizing two layers of FBE provides great versatility in coatings for

pipeline protection. Two-layer FBE systems utilize the application of a second FBE on top of

the base FBE corrosion coating. The top layer typically, but not necessarily, is deposited

during the melt (pre-gelation) stage of the primary layer. The result is an intimate chemical

bond between the two layers. A significant advantage of multilayer technology is that unique

characteristics can be developed by selection of different coating layers with specific

properties. Each layer can be designed to impart specific characteristics that combine to

produce performance results that significantly exceed those of a single-layer coating.

The first layer has the properties of a standalone FBE coating, providing excellent adhesion

and resistance to cathodic disbondment. The top layer provides mechanical damage resistance

from impact or gouging during handling, transportation, and construction. The combination provides the contractor faster, worry-free installation and the pipeline owner with improved

underground coating performance. This system has been used successfully with impingement

and compression-wrapped weight concrete applications. The pipeline construction services

industry has created girthweld coating application systems that can apply dual-layer FBE in

the field so that the entire pipeline has the same coating.



2

Pipeline Coatings - Usage History

1960 1970 1980 1990 2000

FBE

FBE - Dual Layer

3-Layer PE/PP

C o a t i n g M a t e r i a l

Year

Three-layer FBE primed

polyolefin coatings.

Introduced in the late

1970s, 3-layer polyolefin

coatings were put into

practice around 1980. This

coating system is based onearlier pipeline coatings

and combines FBE and

polyolefin materials to

offer customized systems

designed to fulfil

environment requirements.

This system is an effective

solution in situations where

extraordinary coating

damage is highly probable

or elevated temperature

service is likely.

The three types of FBE based coating systems have a relatively long history as seen in Figure

1.

MECHANISM OF CORROSION

One general definition of corrosion is the degradation of a material through environmental

interaction.

As extracted from its ores (metal oxides: Hematite Fe2O3, Bauxite Al2O3·H2O), a significant

amount of energy is put into metal placing it in a high energy state. In accordance to one of

the principles of thermodynamics, materials will always seek the lowest energy state. In caseof metals they tend to lose their energy by reverting to compounds more or less similar to

their original states, which in most cases is an oxide or some other compound. This process by

which metals convert to the lower energy oxides is called corrosion. Corrosion occurs for

most common engineering materials at ambient temperatures in water-containing

environments. The aqueous environment and its electrochemical nature are also referred to as

the electrolyte and, in case of underground pipelines, is the moist soil.

The corrosion reaction chemistry is electrochemical in nature. When metal atoms are exposed

to an environment containing water molecules, they can give up electrons (oxidation)

becoming themselves positively charged ions provided that an electrical circuit can be

completed. The oxidation is called the anodic reaction. The consumption of those electrons by

the reduction reaction of oxygen or water is commonly called the cathodic reaction. Theoxidation reaction causes the actual metal loss, but the reduction reaction must be present to

consume the electrons liberated by the oxidation, maintaining charge neutrality. Otherwise, a

large negative charge would rapidly develop between metal and electrolyte and the corrosion

process would cease.

CORROSION PREVENTION

The principal methods for corrosion prevention on underground pipelines are coatings and

cathodic protection.

Figure 1. A truncated history of pipeline coatings.



3

Coatings are intended to form a continuous film of an electrical insulating material over the

metallic surface to be protected. The function of such a coating is to isolate the metal from

direct contact with the electrolyte, interposing a high electrical resistance so that

electrochemical reactions cannot occur.

FBE systems are effective in the prevention of underfilm corrosion due to their excellent barrier properties including low oxygen permeability. Oxygen permeability of FBE is less

than one-fifth that of polyethylene. However, FBE coatings have a higher moisture

permeability rate than PE coatings.

Cathodic Protection (CP) is a technique to reduce the corrosion rate of a metal surface by

making it the cathode of an electrochemical cell. This is realized by shifting the potential of

the metal in the negative direction by use of an external power source. For CP to work,

current must be discharged from an earth connection called a ground bed. In the process of

discharging the current in a sacrificial system, the anodes in the ground bed are consumed by

corrosion.

COATINGS

Single Layer FBE. Since a New Mexico company coated the first FBE pipeline in 1960, this

technology is now the number one pipeline-coating in North America. It is used on pipes,

bends, girthwelds, and fittings. It is also used in the oil, gas, and water markets. It has been

installed in the ocean, the arctic, in the mountains and in the plains. 1 Figure 2 shows the

improvement in cathodic disbondment resistance of FBE pipecoatings in the last fifty years.

FBE Cathodic-Disbondment-

Resistance Improves with Chemistry

90 days, 23

o

C, 3% ASTM G 8 electroly te, -1.5 V

0

5

10

15

20

25

30

35

1965 1980 1995

Year

C a t h o d i c D i s b o n d m e n t - m m r

Figure 2. There have been significant improvements in FBE coating technology in the

nearly fifty years in the market.



4

Long years of experience demonstrate the following benefits for single layer FBE:

1. Excellent adhesion to steel; good chemical resistance

2. Non-shielding to CP – if it fails, it fails friendly

3. No reported cases of stress-corrosion cracking (SCC) of pipe coated with FBE

4. Resistant to biological, insect, termite, and root attack

5. Installation friendly• Excellent penetration resistance, good abrasion and gouge resistance

• Good impact resistance

o Impact damage is limited to the point of contact

o Damage is easily seen

o Damage is easily repaired

• Good flexibility

Dual Layer FBE. The first dual-layer FBE (DLFBE), introduced in 1992, was for high-

operating temperature pipelines. That was followed in 1998 by the first abrasion resistant

outer (ARO) coating for directional drill pipeline installation. DLFBE, see Figure 3 maintains

the excellent performance and installation characteristics of single-layer FBE, but provides

even better damage resistance, with a slight reduction in flexibility. The dual-layer system provides many of the advantages of three-layer systems – see Table 1.

The ARO system utilizes a high performance FBE as a base layer with a top coat of a

mechanically hard FBE, which ensures a tough outer layer resistant to gouge, impact,

abrasion and penetration. Today’s dual FBE system is sometimes used for the entire pipe line

length (Kern River project, 1150 km of 30 and 42 inch pipe at a nominal thickness of 500

microns; Koyali-Ratlam pipeline Project in India, 262 km).

Figure 3. Dual Layer FBE systemThe relative cost between single-layer FBE, dual layer FBE, and three-layer polyolefin

coating systems depend on many variables, such as: commodity (solid epoxy, PE) costs that

affect coating materials, applicator plant productivity, and coating thickness specifications.

Those costs will also vary from region to region and applicator to applicator. Pipe diameter

and wall thickness can play a role because most specifications call for increased polyolefin

thickness as pipe diameter goes up – see Figure 4.



5

Table 1. Comparison of dual-layer FBE with 3-layer PE.

DFBE COATING 3LPE COATING

CP Current Requirements are low Low

Coating is hard and slippery PE is soft but slippery

Temp Resistance:≤110ºC ≤70ºC typical

Easy Detection of holidays Difficult

Easy Repair Complex

Attention required for handling Handling is relatively easy

Flexible Flexible

Dunnage, separators, strapping Moderate needs

Protection from weld spatter Moderate needs

Foam pads, sand bags, padding Not required

≤2 inch Diameter OK

(Backfill)

2 inch Diameter OK

(Backfill)

Cost Advantages of DFBE Coating over 3LPE Coating

• Lower raw material cost-saving of about 21% in raw material cost alone (depends on

pipe diameter and specification)

• Lower application cost (Extruders not required)

• Less storage space and inventory carrying cost for raw materials

• Energy and time saving in cut back operation

• Lower transportation cost

• Easy repair of holidays at plant and site

• Higher application

line speed and

productivity

In the Indian market,

storage of raw materials

can be a significant cost

because the polyolefin is

frequently imported and a

large holding area is

required. FBE materials

are locally manufactured

with a short lead time for

supply of materials.

Performance benefits

• Very strong

chemical interlayer

bonding between

epoxy layers

• Very high gouge

resistance

• Top layer can be

chosen for anti-slip

properties

Material Cost Savings

D F B E v s . 3 -L P E

0 %

5 %

10 %

15 %

2 0 %

2 5 %

3 0 %

3 5 %

4 0 %

3 0 0 5 0 0 7 0 0 9 0 0 110 0

Pipe Diameter - mm

P e r c e n t S a v i n g s w i t h D F B E

Pi pe OD - m m 3- La ye r

Thick mm

≤273.1 mm 1.625

>273.1 - < 508 mm 1.825

≤508 - < 813 mm 2.125

>813 mm 2.625

Pip e OD - mm DFBE

Thick mm

All 0.625

Thickness Source:

EIL/Bharat Spec 6581-00-16

Figure 4. Material costs of DLFBE and 3-layer coatings

depend on pipe diameter. This is an example from India

showing that the larger PE thickness required for larger

diameter pipe significantly affects cost.



6

• Easy joint coating with liquid epoxy or high performance dual-layer FBE coating.

• Improved adhesion in hot-water soak adhesion test at temperatures over 95ºC.

Reference projects

• Kern River Pipeline, USA (36”, 42” x 1400 km)-Operational since 2001

• West to East Pipeline, China (40” x 400 km)

• West Seno Gas Pipeline, Indonesia (12”x 180 km)• Bud Pipeline, Brazil (36”x 300 km)

• Koyali Ratlam Pipeline, India (16”x 262 km)

• Shanghai Pipeline, China (32”x 300 km)

• Cameron Highway, USA (24”x 166 km)

• ATF Pipeline, India(8”x 96 km)

• MDPL Augmentation, India(22”x 20 km)

• Panipat Jalandhar Pipeline, India (10”x 250 km)

Three Layer

Three-layer polyolefin coatings were introduced about 1980 in Europe. They consist of:• FBE primary coating

• Polyolefin-adhesive (or tie) layer

• Polyolefin topcoat

In some case, more layers are added to provide thermal insulation, a weight coating, or a

frictional coating. The three layers combine the low oxygen permeability of FBE with low-

water permeability of polyolefins. The thick layer of relatively damage resistant polyolefin

provides the coating properties friendly to installation under harsh or inexpert conditions.

There is a trade off between extra cost for the three layer system and potential savings from

such things as reduced use of graded or imported backfill. Other things to consider are the

concern about cathodic shielding and performance of available girthweld coatings compatible

with three-layer polyolefin coating systems.

PERFORMANCE OF SINGLE AND DUAL LAYER FBE SYSTEMS

Fusion-bonded epoxy is a one-part, thermosetting-epoxy resin powder that utilizes heat to

melt, crosslink, and adhere to a metal substrate.2 It provides a coating with excellent adhesion,

and a tough, smooth finish resistant to abrasion, chemical degradation, and soil-stress damage.

It is a 100% solids system with no solvents.3

This combination of properties – particularly the

ease of use and physical and chemical durability – make FBE an ideal choice as a protective

coating under a wide variety of environmental conditions.4

As a summary there are a number of properties that make FBE coating materials useful as

pipe coatings:

• Excellent adhesion to steel.

• Good chemical resistance.

• Resistance to biological attack

• Non-shielding – works with cathodic protection (CP)

• Cathodic Disbondment Resistance

• Flexibility

• Impact resistance.

• Gouge resistance

• Penetration resistance



7

• Abrasion resistance

• High friction surface (Anti-Slip) available

• High Temperature performance coatings available

Adhesion to Steel

Adhesion is an important property for all coatings. Three tests commonly used to measure

adhesion are overlap shear, pull-off and X-cut.

Overlap shear test. Test results indicate the shear strength of the coating. The failure mode is

normally cohesive. The coating is ripped apart leaving it adhered to the metal. Since the

coating is still adhered to the test plates, the adhesion is, in reality, greater than the measured

value. See Figure 5 for photos of the overlap shear test.

Figure 6. The pull-off test provides useful information on coatings that have seenenvironmental exposure e.g. hot-water immersion.

Pull-off test. This test method can be used to compare one coating to another as a measure of

relative adhesion-retention capability. The test is conducted by attaching a dolly to the

coating. The most common procedure uses a liquid epoxy to glue the dolly to the cured

coating. In this case, failure is normally within the glue or at one of its interfaces. In case

coating adhesion is reduced by hot water immersion, it may be possible to obtain a value for

adhesion. This test is not effective on newly-coated FBE. See Figure 6 for photos of the pull-

off adhesion test.

Figure 5. Overlap shear test results are normally cohesive,

e.g., the adhesion strength is grater than the cohesive

strength of the epoxy.



8

X-cut adhesion test. A knife or sharp razor blade is used to cut an “X” in the coating to the

substrate at an approximate 30° angle – see Figure 7. A knifepoint is used to flick the coating

at the point of intersection. Normally, the coating cuts and breaks cohesively, but does not

peel as a result of the flicking action, leaving coating attached to the substrate.

Moderate adhesion results in small chips removed from the steel surface. Poor adhesionresults in removal of large intact pieces of the coating. Test results have to be carefully

evaluated as they can give erroneous results if the coating has softened or has porosity.

Chemical Resistance

Epoxies are well recognized for having good chemical resistance. There are differences

depending on the formulation, e.g., acid-anhydride-cured coatings generally have better acid

resistance than amine-cured systems and less resistance to bases.5

However, amine-cured FBE

still has excellent resistance to both acids and bases. A rule of thumb for FBE pipelinecoatings is that if the pH is measurable with paper, i.e., pH of 2 to 13, the coating will perform

well in the environment. Generally, hydrocarbon spills do not attack FBE pipeline coatings.6, 7

Soil chemicals do not typically attack an FBE coating. Some chemicals may affect the

cathodic-disbondment reaction and accelerate or slow the loss of adhesion around a holiday,

but do not attack the coating itself. If there is a holiday and insufficient or no cathodic

protection, a corrosive agent such as acid will attack the exposed metal and corrosion can

undermine the coating.

If there are no holidays, a coating performs better in salt water than in fresh water. Fresh or

deionized water has a higher osmotic gradient and, if contaminants are present under the

coating, causes blistering faster than salt water.

FBE coatings are resistant to damage by solvents. Some, such as alcohols, can soften an FBE

and cause it to swell, increasing susceptibility to damage. Oxidizing agents can also attack the

coating, resulting in thickness loss. Pipelines through landfills, chemical dumps, or around

chemical plants may be susceptible to chemical attack. Higher temperatures normally

accelerate any chemical reaction. Checking with the coating manufacturer provides guidance

for concerns about exposure to solvents, oxidizing agents, or chemical dumps.8

Figure 7. Outside the laboratory, the most common

way to test coating adhesion is the “X” test.



9

Resistance to Biological Attack

A World War II study demonstrated that to avoid fungal or bacteria attack, the coating should

be formulated with materials that cannot be used by biological organisms for food.9

A 1969 study of over twenty epoxy coatings, including two early FBE pipe coatings, showed

them to be funginert according to Method 508 of Specification MIL-STD-810B.10, 11

Termite resistance of FBE coatings was demonstrated in a 1975 Australian study. After

exposure, following the procedure of Gay, Greaves, Holdaway, and Wetherly, to 84 days in

colonies of Coptotermes acinaciformis and Mastotermes darwiniensis, the two FBE pipe

coatings were undamaged.12

The visual assessments followed those by Gay and Wetherly.13, 14

Even under a microscope no surface nibbles were seen on the FBE.

In contrast, samples of vinyl and PE tape, heat-shrink sleeves, extruded PE, and coal tar all

suffered damage from Coptotermes acinaciformis. All but the shrink sleeve and one of the

extruded PE coatings were attacked by Mastotermes darwiniensis.

Non-Shielding

An electrical shield can be defined as a barrier of any nature that will prevent or divert from a

pipeline the flow of CP current. This electrical shielding may result from a non-metallic

insulating barrier or from the diversion of the current to another metallic structure in the

electrical path between the ground bed and the pipeline to be protected.

Current Requirements vs. Coating Type

Log Scale - Canadian Experience

1

10

100

1000

FBE PE CTE AE

Coating Type

C u r r e n t - m i c r o A / m 2

0

15

Years

Figure 8. Current requirement measurements by a major Canadian gas companyshowed a significant difference among pipecoatings in their system. FBE = Fusion

Bonded Epoxy single layer, PE = two-layer PE utilizing a rubberized asphalt adhesive,

CTE = coal-tar enamel, and AE = asphalt enamel.

If the barrier is an insulating material sufficiently porous to absorb moisture and become

conductive, enough current may pass to ensure a CP of the pipe. Such a barrier will not then

act as a shield.



10

Moisture from the environment can cause a reduction in the volume resistivity of an FBE

coating from approximately 1015

ohm cm to 1013

ohm cm. As such, the conductivity is low

enough to allow some current to pass through, but is still high enough to keep the current

requirement very low.. As a result, it is possible to protect the entire steel surface, even in

local areas where poor substrate cleaning has resulted in some adhesion loss. However, due to

the low oxygen concentration at the metal surface, the CP current required for protection is

kept small, even though the entire steel surface is protected.

In contrast to FBE coatings, two-layer, three-layer, and tape polyethylene or polypropylene

coating systems are much less conductive. As a result, these coatings may completely block

(or shield) cathodic protection. In other words, cathodic protection current can not be

“thrown” through the coating. As a result, if there is coating disbondment from the steel

surface due to impact or gouge damage, mechanical blockage, or contamination, it will be

difficult or, in many cases, impossible to provide CP current to the affected area. Thus,

corrosion will occur at these sites once water and oxygen get into those areas, even though a

CP system is used on the pipeline.15

Cathodic Disbondment Resistance

As a QC test, cathodic disbondment is an important measure of coating adhesion to the steel

surface. Reduced disbondment also means reduced current requirements over the life time of

the pipeline. Not all FBE coatings perform equally well. See Figure 9 for examples of

cathodic-disbondment resistance of several commercially available FBE coatings.

Different FBE Systems Prov ide Varying CD Resistance

28 Day, 65oC, -1.5 volt, 3% NaCl

0

2

4

6

8

10

12

14

A B C D E F G

FBE Coating System

C D

D i s b o n d m e n t - m

m r

Figure 9. Cathodic Disbondment. CD resistance varies significantly among commercialavailable coatings.

Ensuring a clean, non-contaminated steel surface is the key condition to have good adhesion

of any coating, including FBE. Contaminants come from many sources: plate from the mill,

pipe manufacturing process, transportation, handling etc.

Although the blast cleaning process removes a large amount of contaminants, it is often

insufficient for optimum performance. A phosphoric acid wash is an effective method for



11

removing residual contaminants. If properly done, this can be considered as an insurance

policy that protects against unknown, unexpected or not observed contamination.

Good performance of all coatings is a function of proper pipe surface conditioning and

preparation. No matter what coating system is in use, if the surface has proper profile and

peak, the cleaner the pipe surface, the better the coating performance is.

Flexibility

Most pipelines require bending to meet the contours of the landscape or the installation

process16, 17

– see Figure 10. For sharp bends, the pipe is bent first and then coated.

Figure 10. Laboratory tests (A) are able to demonstrate bendability comparable to field

experience and are useful for comparing coatings. Photo (B) shows a field bend in

process. Photo (C) illustrates the use of a reel barge for offshore pipe installation. Reel-

barge installation requires greater coating flexibility because of smaller radius bends.

Flexibility requirements are greatest for pipe at the reel core and diminish withsucceeding layers of pipe. The coating must be designed to meet the core bending

requirements. Photograph (D) shows pipe bent to fit the contours of the land.

Impact Resistance

Any organic material caught between a rock and a hard place, e.g., steel, is going to suffer.

The range of impact force during pipe handling and installation varies greatly depending on

handling techniques, accidents, and procedures.

Improved impact resistance means less damage. FBE coatings have several valuable

characteristics when it comes to impact damage:

• Good impact resistance• Impact damage is limited to the contact point

• Damage is easily seen

• Damage is easily repaired

For some coating systems, damage extends beyond the impact zone. For FBE coatings, the

damage is normally limited to the point of collision. Unlike some coatings that disbond

without complete penetration, the damage for FBE coatings is easily seen. Two-part liquid

coatings or hot-melt patchsticks make the repair easy. When total damage and cost of repair

are taken into account, FBE may provide the best economic answer.



12

FBE vs. Dual Coat

9 mm plate, 23

o

C, 16 mm tup

0

2

4

6

8

10

12

FBE - 375 Dual - 375

Coating - at 375 microns

I m p a c t - J

Figure 12. Dual-coat technology can provide significant performance

improvement. In designing Dual layer FBE systems for high impact resistance,

both the design of the base coat and topcoat are important.

Evaluating impact test data is complicated by the fact that there are several test variables

that drastically change the reported results, see Figure 11. The most important one is the

substrate. The force of the impact is borne by both the coating and the substrate. If the

Figure 11. A substrate with give absorbs much of the impact force and protects

the coating from damage. Lowering the test temperature increases the rigidity of

the coating and makes it more susceptible to impact damage.



13

substrate is thin enough to deform, it absorbs much of the force and allows the coating to

survive intact.

There are several ways to improve impact resistance utilizing dual-layer FBE systems. In

designing dual coat systems for high impact resistance, both the design of the basecoat and

the topcoat are important.

Dual-coat technology can provide significant performance improvement without a major economic penalty. See Figure 12, a dual coating system at the same thickness of a stand-alone

FBE provides significantly improved impact resistance.

A properly formulated dual-layer FBE system can show improved impact resistance

compared to the same thickness of a stand-alone FBE pipe coating.

Gouge Resistance

Gouge resistance is important for coatings used for directional-bore pipeline installation.

Dual-layer FBE systems can have improved damage resistance – see Figure 13. The basecoat

is designed as a corrosion coating with good adhesion; the topcoat, in this case, provides

damage and gouge resistance. An abrasion-resistant dual-layer FBE system makes a good

choice for pipe installed via directional boring, utilizing rough construction practices, or

installation in rugged terrain. These hard coatings are employed to resist gouging, cutting, and

penetration from sharp backfill. Although flexibility is slightly reduced, specific formulations

enable the coating to remain undamaged even when bent to a radius more severe than that

permitted for the underlying steel.

Figure 11. Gouge resistance is particularly important for coatings used for directional-

bore pipeline installation. Laboratory gouge tests have been developed to compare

resistance to abrasion damage.

FBE: Directional BoreTISI Test: R33 Carb ide Bit/50 kg Load

0.00

0.20

0.40

0.60

0.80

1.00

1.20

Dual A Dual B FBE Epoxy

Concrete

Dual C PE

Coating

G o u g e - m m



14

Penetration Resistance

A major problem with early thermoplastic coatings was cold flow during storage. The weight

of the pipe and hot days caused the coating material or adhesive to deform or split. A

penetration or indentation test is designed to measure the resistance to flowing at expected

storage or operating temperatures.

FBE coatings are thermosetting and have high-compression strength. Pipe with FBE coating

can be stacked as high as safety allows – see Figure 14. Penetration resistance is also

important after installation where the weight of the pipe rests on small stones or other hard

objects in the ditch fill material. It also allows for more efficient pipe laying methods such as

the use of a roller cradle.

Figure 12. FBE coatings resist damage due to indentation or deformation.



15

Abrasion Resistance

Abrasion resistance is a factor in many performance situations – see Figure 13 for a backfill

example. During transportation, cinders and grit can get between pieces of pipe. For that

reason, there should be separators to prevent intimate contact between pipe joints. Normal

handling often includes accidental dragging along a hard surface, such as wood supports.

Abrasion also takes place during directional drill installation and back filling.

In summary, FBE and DLFBE coating systems provide a balance of properties suitable for most pipeline installations.

FBE/DLFBE COATINGS AND CATHODIC PROTECTION IN THE FIELD

Earlier discussions in this paper have been theoretical and based on laboratory tests. This

section will provide actual examples of observations and measurements on pipelines and is in

the form of case histories.

Case History 1 – Large Diameter Pipeline in Western US

The project includes two parallel pipelines 36" in diameter by about 1100 km in length. 18The

first pipeline was coated and installed in the early 90s with single layer FBE. The second line

was installed in about 2003 and coated with dual layer FBE with a nominal thickness of 22

mils (550 microns) of dual layer FBE. The current requirements of the original pipeline wereso low that they did not add additional CP equipment beyond connecting the two pipelines.

They did upgrade the CP systems for the compressor stations.

Figure 13. While FBE coatings resist damage from impact

and abrasion, specialized equipment is available to remove

large rocks from the ditch-excavation spoils and apply thesized materials directly into the ditch. Photo courtesy of

Ozzie’s Directional.



16

The pipelines are interlinked with six compressor stations. Even though they have their own

CP systems, some of the current from the pipelines also feeds the compressor stations and

current readings are higher because of that. There is bare copper at each station and the last

ground bed also must protect zinc ribbon used to dissipate current from an overhead line. The

actual current required to protect the FBE coated lines is less. The total current required to

protect the 2189 km of 36” pipe was 136 amps for an average of 21.7 microamps per square

meter. Average distance between groundbeds to protect the dual lines was 57.56 km. Pleasesee Figure 14 for current required for each groundbed as measured on April 11, 2008. at that

time, one of the lines was 16 years in the ground and the other five years. Also see Table 2 for

a summary of the pertinent pipeline statistics.

Figure 14. Current requirements on each groundbed as measured on April 11, 2008 on

1100 km parallel pipeline, one coated with FBE and the other with DLFBE.

Table 2 Details on the Case History 1 pipeline.

Total Pipeline length 2189 km

Micro amps/m2 21.7

Average d is tance between groundbeds 57.6 km

Case History 2 – Two FBE Coated Projects in Eastern US

Project 1 = 11 miles of 24" OD pipe in the Northeastern US

Project 2 = 9.5 miles of 20" OD pipe in the Northeastern US

Project supervision reported that the coated pipe handles and transports with little damage as

long as contractors handle adequately.19

No feedback from contractors on either project. No

information was gathered on current density except at directional drilled sites. This was FBEwith an abrasion resistant overlay. Current density on the horizontal directional drill (HDD)

lines was measured from around 0.5 to 16 microamps/meter squared/100 mV.

The key finding in this case history was that even after directional drill installation, the

current requirements ranged from only 0.5 to 16 µA/m2.

Case History 3 – FBE Coated Line in US

This project was a 133 km single layer FBE line. A single impressed current ground bed at

mile 61 protects the entire line. There were no compressor stations in this section. The six

Current Requirement vs . Ground Bed Number

0

5

10

15

20

0 5 10 15 20

Ground Bed Number

A m p e r a g e



17

year old pipeline required 11 µA/m2 to achieve protection. 20 See Table 3 for the project CP

summary.

Table 3. Pertinent details of Case History 3.

Total Pipeline length 133 km

Micro amps/m2

11.0

Location of groundbed Mile 61Date of Installation 2002

In summary, many of the existing standards for cathodic protection current requirements and

projections for the requirements over the life of the pipeline are written by people with little

or no experience with FBE coated pipelines. For that reason, they include a very conservative

estimate of installation current requirements and high breakdown factors that do not fit actual

experience.

CONCLUSIONS

FBE systems have a long track record as effective pipeline coatings. FBE systems provide

pipeline owners also with an economically attractive, damage-resistant, and non-shieldingcoating system that can be used from one end of the pipeline to the other.

Another factor is application plant productivity. This is very plant specific, but frequently

throughput for DLFBE is 10% to 15% or even higher compared to 3-layer polyolefin

application. FBE coating materials are locally manufactured and do not require the long lead

times and storage facilities needed for imported polyolefin materials.

A factor that makes FBE systems effective in the prevention of underfilm corrosion is their

excellent adhesion to steel, high physical performance, low oxygen permeability and the

capability not to shield CP current.

It has been well documented that the weakest regions for corrosion protection on a pipeline

are the weld area and field joints. In such areas, it is considerably more likely that the rate of water and oxygen ingress will be high. In addition, the water, oxygen, and other aggressive

species are able to travel freely along the weld seam if poor surface cleaning was done, or an

overlapping weld cap is present. Cathodic shielding can allow corrosion in these areas. FBE

coated pipelines can utilize easily applied FBE coatings or two-part coating systems that

provide excellent performance and do not shield the steel from cathodic protection.

As a technology, FBE pipeline coatings continue to be important. Its success as a corrosion

mitigation system due to excellent chemical resistance, physical properties, ease of use, and

competitive pricing has lead to steadily increasing market share. FBE coatings consistently

meet the demands placed in a wide variety of industrial environmental applications. FBE

coatings have a successful track record for protecting pipelines around the globe – from the

highly aggressive environment of the Middle East region, to the extreme conditions in thearctic, to swamps, to mountains and to the ocean depths.

1A. Kehr, M. Mallozzi, Fast, worry free pipeline installation with dual-layer FBE Coatings, ACA Corrosion

Control 007, November 25-28, 2007, Sydney.2

D. G. Enos, J. A. Kehr, C. R. Guilbert, “A High-Performance, Damage-Tolerant, Fusion-Bonded Epoxy.3 H. Lee, K. Neville, Handbook of Epoxy Resins, (New York: McGraw-Hill Book Company, 1967).

4J. Alan Kehr, A Foundation of Pipeline Corrosion Protection. (Houston, NACE, 2003).

5J. Banach, “FBE: An End-User’s Perspective,” NACE TechEdge Program, Houston , Using Fusion Bonded

Powder Coating in the Pipeline Industry, June 1997.



18

6

C. G. Munger, Louis D. Vincent, Corrosion Prevention by Protective Coatings, 2nd

ed., (Houston, TX: NACE,

1999), p. 50.7

D. G. Temple, K. E. W. Coulson, “Pipeline Coatings, Is It Really a Cover-up Story? Part 2,” Paper 356,Corrosion 84, (Houston, TX: NACE, 1984), p.1.8

J. A. Kehr, D. G. Enos, “FBE, a Foundation for Pipeline Corrosion Coatings,” Corrosion/00, paper no. 00757,

(Houston, TX: NACE, 2000)9

C. G. Munger, Louis D. Vincent, Corrosion Prevention by Protective Coatings, 2nd

ed., (Houston, TX: NACE,1999), p. 53.10

Enviroline Laboratories, Letter of Certification, Minneapolis, MN, February 17, 1969.11

MIL-STD-810F(1), “Insulating Compound, Electrical, Embedding, Epoxy,” November 1, 2000, (Philadelphia,

PA: Document Automation and Production Service (DAPS), 2000).12

Bulletin No. 277, (Melbourne, Victoria: CSIRO, 1955), pp. 1 – 60.13 J. A. L. Watson, R. A. Barrett, “Report of Laboratory Tests to Determine the Termite Resistance of Protective

Plastic Coatings, Tapes, and Resins for Steel Pipe,” July 1975.14

Technical Paper No. 10, (Melbourne, Victoria: CSIRO, 1969), pp. 1 – 49.15

A. W. Peabody, Peabody’s Control of Pipeline Corrosion.16

ASME B31.8, “Gas Transmission and Distribution Piping Systems,” 1995, p 36.17

ASME B31.4, “Pipeline Transportation Systems for Liquid Hydrocarbons and Other Liquids,” 1998.18

B. Schow, telephone interview, April 11, 2008.19

Anonymous, data provider asked not to be identified, email, January 20, 2009.20

T. Fore, Kinder Morgan, telephone interview April 10, 2008.

Documents

Abstract a Land Ke Hr