webinar pipeline coatings

7/29/2019 Webinar Pipeline Coatings

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PAINT SQUARE WEBINARFIELD INSPECTION AND

REPAIR OF TRANSMISSIONPIPELINE COATINGSE. BUD SENKOWSKI, P.E.SENIOR CONSULTANTKTA-TATOR, INC.

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WEBINAR CONTENT

Purpose of pipeline coatings

Performance expectations of pipeline coatings

Federal/state requirements for corrosion protection Purpose of field inspection

Field inspection techniques

Field installation and repair of pipeline coatings

Protection of girth welds

Repair of coating damage prior to burial

Field rehabilitation of pipeline coating systems and joints

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WHY DO WE NEED

PIPELINE COATINGS?

Corrosion is the greatest danger

to buried steel pipelines.

Uncontrolled corrosion of thepipe wall leads to leaks, service

interruptions, and even

explosions.

Pipeline owners/operators place

their highest priorities on coatingsystems to prevent corrosion.

Pipeline coatings are applied to

both pipe runs and girth welds.

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A STACK OF COATED PIPE


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PERFORMANCE EXPECTATIONS

OF PIPELINE COATINGS

Long-term protection of the

pipeline steel surfaces from

corrosion.

Compatibility with cathodic

protection.

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INSTAL LING A COATED

PIPELINE IN THE TRENCH


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FEDERAL REQUIREMENTS FOR THE

CORROSION PROTECTION OF BURIED

PIPELINES

All interstate pipelines shall be installed with an

exterior coating system.

Additionally, all interstate coated pipelines shall beprotected by a cathodic protection system

providing:

A minimum pipe-to-soil potential of - 850 mV

Or, a minimum polarization shift of 100 mV.

Many states have similar requirements forintrastate pipelines.

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PURPOSES OF

FIELD COATING INSPECTION

Verify that the coating application meets the

specification requirements for:

Surface cleanliness

Surface profile

Allowable ambient conditions

Dry film thickness (DFT)

Absence of coating holidays (pinholes) Adhesion to steel substrate

Degree of cure

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MATERIALS USED IN

PIPELINE COATING SYSTEMS

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JOINT COATING AND REPAIR

MATERIALS AVAILABLE FOR FIELD USE

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WHY DO PIPELINES HAVE JOINTS?

Pipelines have joints

because they are

fabricated from 40

and 80 coated pipesections.

High pressure pipelines

require a girth weld at

each field joint.

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SETTING A PIPE SECTION IN THE

TRENCH BEFORE WELDING


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WHY MUST JOINTS BE COATED?

Each girth weld must be

coated because the welds

are made on areas that are

bare steel.

The bare area at the end of

each pipe section is called the

cut back area. It can be up

to 12 wide.

All girth welds must be coated

before the line is buried.

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WELDING A PIPE JOINT. NOTE THE CUT-

BACK AREA BETWEEN THE WELD AND

THE YELLOW COATING.


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COATING COMPATIBITY ISSUES WITH

JOINT AND REPAIR MATERIALS

Coatings selected for a

girth applications must be

compatible with the coating

applied to the main pipeline.

In addition to chemical

compatibility, the girth weld

coating must form a tight seal

to prevent water infiltration.

If a generically similar coating

is not available, there are other

joint and repair materials that

will perform.

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LINE-TRAVELL ING UNIT FOR APPLYING

LIQUID EPOXY TO GIRTH WELDS ON AN

FBE COATED PIPELINE


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NEW CONSTRUCTION OR

MAINTENANCE WORK?

New construction utilizes

automatic line travelling

equipment to blast and coat

and cure girth welds.

Replacement and recoating of

single sections and their girth

welds requires materials that

cure under field conditions.

Cold and wet conditions

require special material

formulations.

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A L IQUID EPOXY APPL ICATION TO

THE MAINTENANCE

REPLACEMENT OF A PIPE

SECTION


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WHAT IS MICROCRYSTALLINE WAX?

Microcrystalline wax is a solid

by-product of petroleum that

melts at 160-175F.

When coating girth welds, thewax is heated in a pot to 270-

350F and applied by the

granny rag method to reach

40-60 mils. It can also be applied

by brush to small areas.

The wax develops excellent

adhesion to cleaned steel and

exhibits good flexibility.

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APPLYING MICROCRYSTALLINE

WAX TO A GIRTH WELD USING A

GRANNY RAG


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WHAT ARE COLD-APPLIED TAPES?

Coldapplied tapes are prefabricated materials

made from a polymer backing attached to an

adhesive film. Some may also use a liquid primer.

Petroleum wax

Polyethylene (PE)

PE/PP blends

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WHAT IS PETROLEUM WAX TAPE?

Petroleum wax is a by-product of

crude oil that is mixed with mineral

fillers, plasticizers, and corrosion

inhibitors.

The wax is applied to a polyester meshand used as a tape product over

pipeline and girth weld surfaces.

An additional wax-based filler with

glass micro beads is used to smooth

out irregular shapes prior to coating.

The tape can be applied over tight

rust. It contains no toxic materials and

can be placed in service immediately

after application.

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PETROLEUM WAX TAPE


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WHAT IS POLYETHYLENE (PE) TAPE?

Polyethylene (PE) tape is a cold-

applied joint covering that has an

elastomeric or butyl rubber-

based adhesive.

Tapes use a high-density version

(HDPE)for better resistance to

mechanical damage.

HDPE tapes are compatible withmost pipeline coatings in current

use.

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HDPE TAPE WRAPPED OVER A TEE

IN AN FBE COATED PIPELINE


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WHAT IS A MULTI-POLYMER ALLOY

(MPA) TAPE?

Multi-polymer alloys (MPA)

are proprietary blends of

polymers like polyethylene

(PE) and polypropylene (PP)

They are applied cold with a

pressure-sensitive adhesive.

MPA tapes have temperatureresistance to 250F.

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HIGH TEMPERATURE TAPE

APPLICATION


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WHAT ARE HEAT-SHRINK PRODUCTS?

Heat-shrink products are made

from specially-processed PE or

PP that will shrink when heated.

The reverse side of the sleeve is

coated with an adhesive.

The adhesive layer becomes

molten when heated and upon

cooling completes the seal tothe pipe surface.

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APPLYING A HEAT-SHRINK SLEEVE


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WHAT KINDS OF HEAT-SHRINK

PRODUCTS ARE AVAILABLE?

Heatshrink products include

tube sleeves, wrap-around

sleeves and tape.

Shrink ratios are in the 2:1 and

3:1 with minimal change in the

linear direction along the pipe.

Some wrap-around sleeves

have metal closure strips that

hold them together during

application.

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COMPLETED HEAT-SHRINK SLEEVE

OVER A GIRTH WELD


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WHERE CAN HEAT SHRINK

PRODUCTS BE USED?

Heat shrink products are

available for pipe diameters

in the range of 2 to 60.

They can be used with

virtually all of the pipeline

coatings in current use.

Depending upon the sleeve

material and adhesive they

can be used on pipelines

operating to 230F.

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CONTINUOUS HEAT-SHRINK SLEEVES

APPL IED OVER A SECTION OF

DAMAGED ASPHALT PIPELINE

COATING


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WHAT IS LIQUID EPOXY?

Epoxy is a two-part liquid

coating made by mixing a

resin with a hardener.

After mixing and curing,a hard, tough, chemically-

resistant coating is formed.

Epoxy has excellent

resistance to water

penetration and cathodic

disbondment damage.

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APPLYING LIQUID EPOXY TO A GIRTH

WELD


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HOW IS LIQUID EPOXY

USED FOR JOINTS?

Epoxy is made to work in

many field conditions. It is

applied at 10-20 mils DFT

using brush, roller, or spray.

Surface preparation requires a

surface cleaned to an SSPC-

SP10, Near-White condition.

Air and surface temperatureshould be at least Is 50F.

Lower temperature versions

are available.

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CURED L IQUID EPOXY COATING ON A

GIRTH WELD


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COATING IN COLD WEATHER

Conventional epoxy

formulations will not

cure in cold weather.

Supplemental heat mustbe used to heat the pipe

and cure the resin.

However, low temperature

epoxies are availablethat can be applied and

cured over a 4F to 32F

temperature range.

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APPLYING LIQUID EPOXY IN COLD

WEATHER


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HOW IS FUSION-BONDED EPOXY (FBE)

USED AS A JOINT COATING?

FBE is used the same way

that the material is applied

at the mill, except that the

process is done in the field.

The weld area is cleaned to

SSPC-SP10, Near-White

Metal condition, heated by

induction, and the FBE

applied by electrostaticspray.

Heat completes the cure.

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A L INE-TRAVELLING FBE SPRAY UNIT

FOR GIRTH WELD COATING


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HOW ARE FBE JOINTS APPLIED

UNDER FIELD CONDITIONS?

Girth weld completion must

go on regardless of weather

conditions.

When FBE is applied towelds it may be necessary

to erect environmentally

controlled structures along

the right-of-way.

Welding and coating takes

place within the structures.

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HEATED SHELTERS FOR GIRTH WELD

WORK IN COLD WEATHER


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WHY DO WE REPAIR

SMALL COATING DEFECTS?

Small coating defects can

occur at any time on mill

coated pipe from the point of

manufacture to final burial in

the trench.

Electrical testing (jeeping)

can also reveal holidays that

require repair.

Any unrepaired defect can

become a point of corrosion

on the coated pipe.

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MAGNIFIED VIEW OF IMPACT DAMAGE

ON AN FBE COATING


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REPAIRING PIPELINE COATINGS WITH

POLYMER-BASED TAPES

Defects or damage in many

pipeline coatings can be

repaired with cold-applied

polymer-based tapes.

The tapes may utilize PVC,

HDPE, HDPP, or MPA polymers.

The areas to be repaired canbe prepared by wire brush.

A primer may be necessary to

optimize the adhesive bond of

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HAND-WRAPPING PE TAPE


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REPAIRING PIPELINE COATINGS WITH

HEAT-SHRINK SLEEVES

A variety of coated pipelines,

including FBE and composite,

3-layer HDPE And HDPP, can be

repaired using heat-shrink

sleeves or tape.

Areas to be repaired can be

cleaned by power-driven wire

brush.

The interior sleeve or tape

surfaces will have a modified

butyl rubber adhesive that will

complete the adhesive bond.

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APPLYING HEAT-SHRINK TAPE AT A

GIRTH WELD REPAIR


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PRECAUTIONS WHEN USING HEAT-

SHRINK PRODUCTS

The applications of heat shrink sleeves and tapes

must be closely monitored to ensure that both the

preheating of the steel surface and heat applied to

achieve the shrinking of the material is adequate tomaximize the adhesive bond.

If the temperatures are below levels specified by

the manufacturer, an insufficient bond will form

and lead to failure by water penetration. Pull-offpeel tests provide a means to evaluate the

adhesive bond of heat-shrink products in the field.

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MAKING REPAIRS TO LIQUID-APPLIED

EPOXY AND POLYURETHANE

Pipelines originally coated with

liquid epoxy or polyurethane

coatings can be repaired by re-

applying the same materials.

Exposed metal should be

cleaned to a near-white

condition.

Weather conditions at the timeof repair may require the use of

low temperature tolerant

formulations.

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LIQUID EPOXY APPL ICATION TO A

PIPELINE AREA


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MAKING REPAIRS TO FUSION-BONDED

EPOXY WITH LIQUID/PASTE EPOXY

Small areas of damage in an

FBE coating can be repaired

with a fast-curing, 100% solids,

2- component chemically-cured

epoxy paste supplied in a dual-component dispenser.

Once dispensed, the epoxy

paste is mixed with a spatula

and applied to complete the

repair.

Epoxy products develop a

strong adhesive bond to FBE.

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A HAND-HELD GUN FOR

DISPENSING A 2-COMPONENT

EPOXY REPAIR PASTE


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REPAIRS WITH PLURAL COMPONENTHIGH SOLIDS SPRAY (HSS) UNITS

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Field repairs can also be made by

spraying plural component epoxy

with a high solids spray (HSS) unit.

HSS units are scaled-down,disposable spray units that use

compressed air at 40-50 psi to mix

and spray the contents (40-1000 mL)

of a dual (resin/hardener) cartridge

pack.

For best results, the cartridges

should be heated to approximately

120-130F before use.

HSS DISPOSABLE SPRAY UNIT


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FIELD REPAIRS TO 3-LAYER

COMPOSITE COATINGS

Composite, 3-layer

polypropylene (3LPP) and

polyethylene (3LPE) coatings

can be repaired using hot

microcrystalline wax, coldapplied tape, and heat-shrink

products.

HDPP heat-shrink products

match the thermal and

mechanical resistance of the

original 3LPP composite

coating.

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TESTING A HDPP HEAT-SHRINK

SLEEVE APPL IED OVER A 3LPP

COATING


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JOINT COATING AND REPAIR

MATERIALS AVAILABLE FOR FIELD USE

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QUESTIONS?

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QUESTIONS?

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