webinar pipeline coatings
TRANSCRIPT
-
7/29/2019 Webinar Pipeline Coatings
1/35
PAINT SQUARE WEBINARFIELD INSPECTION AND
REPAIR OF TRANSMISSIONPIPELINE COATINGSE. BUD SENKOWSKI, P.E.SENIOR CONSULTANTKTA-TATOR, INC.
1
-
7/29/2019 Webinar Pipeline Coatings
2/35
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
2
-
7/29/2019 Webinar Pipeline Coatings
3/35
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.
3
A STACK OF COATED PIPE
-
7/29/2019 Webinar Pipeline Coatings
4/35
PERFORMANCE EXPECTATIONS
OF PIPELINE COATINGS
Long-term protection of the
pipeline steel surfaces from
corrosion.
Compatibility with cathodic
protection.
4
INSTAL LING A COATED
PIPELINE IN THE TRENCH
-
7/29/2019 Webinar Pipeline Coatings
5/35
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.
5
-
7/29/2019 Webinar Pipeline Coatings
6/35
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
6
-
7/29/2019 Webinar Pipeline Coatings
7/35
MATERIALS USED IN
PIPELINE COATING SYSTEMS
7
-
7/29/2019 Webinar Pipeline Coatings
8/35
JOINT COATING AND REPAIR
MATERIALS AVAILABLE FOR FIELD USE
8
-
7/29/2019 Webinar Pipeline Coatings
9/35
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.
9
SETTING A PIPE SECTION IN THE
TRENCH BEFORE WELDING
-
7/29/2019 Webinar Pipeline Coatings
10/35
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.
10
WELDING A PIPE JOINT. NOTE THE CUT-
BACK AREA BETWEEN THE WELD AND
THE YELLOW COATING.
-
7/29/2019 Webinar Pipeline Coatings
11/35
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.
11
LINE-TRAVELL ING UNIT FOR APPLYING
LIQUID EPOXY TO GIRTH WELDS ON AN
FBE COATED PIPELINE
-
7/29/2019 Webinar Pipeline Coatings
12/35
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.
12
A L IQUID EPOXY APPL ICATION TO
THE MAINTENANCE
REPLACEMENT OF A PIPE
SECTION
-
7/29/2019 Webinar Pipeline Coatings
13/35
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.
13
APPLYING MICROCRYSTALLINE
WAX TO A GIRTH WELD USING A
GRANNY RAG
-
7/29/2019 Webinar Pipeline Coatings
14/35
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
14
-
7/29/2019 Webinar Pipeline Coatings
15/35
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.
15
PETROLEUM WAX TAPE
-
7/29/2019 Webinar Pipeline Coatings
16/35
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.
16
HDPE TAPE WRAPPED OVER A TEE
IN AN FBE COATED PIPELINE
-
7/29/2019 Webinar Pipeline Coatings
17/35
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.
17
HIGH TEMPERATURE TAPE
APPLICATION
-
7/29/2019 Webinar Pipeline Coatings
18/35
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.
18
APPLYING A HEAT-SHRINK SLEEVE
-
7/29/2019 Webinar Pipeline Coatings
19/35
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.
19
COMPLETED HEAT-SHRINK SLEEVE
OVER A GIRTH WELD
-
7/29/2019 Webinar Pipeline Coatings
20/35
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.
20
CONTINUOUS HEAT-SHRINK SLEEVES
APPL IED OVER A SECTION OF
DAMAGED ASPHALT PIPELINE
COATING
-
7/29/2019 Webinar Pipeline Coatings
21/35
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.
21
APPLYING LIQUID EPOXY TO A GIRTH
WELD
-
7/29/2019 Webinar Pipeline Coatings
22/35
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.
22
CURED L IQUID EPOXY COATING ON A
GIRTH WELD
-
7/29/2019 Webinar Pipeline Coatings
23/35
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.
23
APPLYING LIQUID EPOXY IN COLD
WEATHER
-
7/29/2019 Webinar Pipeline Coatings
24/35
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.
24
A L INE-TRAVELLING FBE SPRAY UNIT
FOR GIRTH WELD COATING
-
7/29/2019 Webinar Pipeline Coatings
25/35
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.
25
HEATED SHELTERS FOR GIRTH WELD
WORK IN COLD WEATHER
-
7/29/2019 Webinar Pipeline Coatings
26/35
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.
26
MAGNIFIED VIEW OF IMPACT DAMAGE
ON AN FBE COATING
-
7/29/2019 Webinar Pipeline Coatings
27/35
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
the tape.27
HAND-WRAPPING PE TAPE
-
7/29/2019 Webinar Pipeline Coatings
28/35
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.
28
APPLYING HEAT-SHRINK TAPE AT A
GIRTH WELD REPAIR
-
7/29/2019 Webinar Pipeline Coatings
29/35
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.
29
-
7/29/2019 Webinar Pipeline Coatings
30/35
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.
30
LIQUID EPOXY APPL ICATION TO A
PIPELINE AREA
-
7/29/2019 Webinar Pipeline Coatings
31/35
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.
31
A HAND-HELD GUN FOR
DISPENSING A 2-COMPONENT
EPOXY REPAIR PASTE
-
7/29/2019 Webinar Pipeline Coatings
32/35
REPAIRS WITH PLURAL COMPONENTHIGH SOLIDS SPRAY (HSS) UNITS
32
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
-
7/29/2019 Webinar Pipeline Coatings
33/35
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.
33
TESTING A HDPP HEAT-SHRINK
SLEEVE APPL IED OVER A 3LPP
COATING
-
7/29/2019 Webinar Pipeline Coatings
34/35
JOINT COATING AND REPAIR
MATERIALS AVAILABLE FOR FIELD USE
34
-
7/29/2019 Webinar Pipeline Coatings
35/35
QUESTIONS?
35
QUESTIONS?