Best Management Practice

Use of Reinforced Composite Pipe

(Non-Metallic Pipelines)
August 2022
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Overview
This guide is meant to provide increased awareness among designers, installers and
users of non-metallic reinforced composite pipeline systems, of some industry practices
and lessons learned regarding reinforced composite pipelines used by the upstream oil
and gas industry. This guide is not intended to be a detailed guide or design manual on
the use of these materials for pipeline applications. Significant industry literature and
documentation already exists on the design, manufacturing, installation and operation
of reinforced composite pipelines. This information currently resides in pipe
manufacturers’ manuals, and various industry standards and guides published by
organizations such as ASTM International, American Petroleum Institute (API), American
Water Works Association (AWWA) and International Organization for Standardization
(ISO).
In Canada, the oil and natural gas industry pipeline code, CSA Z662-191, has a complete
chapter dedicated to non-metallic pipeline systems (see Clause 13.0), which also
includes specific requirements for reinforced composite pipelines (see Clause 13.1).
This guide intends to complement these existing industry documents and standards and
not to replicate their contents.
Therefore, the main intention of this guide is to address the following:
• Differences between conventional steel pipe and reinforced composite pipe.

• Lessons learned and recommended best practices as gathered from Canadian

industry experiences.

• Provide some guidance for designers, installers and users who may have limited
experience with reinforced composite pipelines.

Users should consult with the manufacturers of the pipe products in use, or being
evaluated for use, for clarifications and suggestions regarding the best practices,
considerations and applications of the materials in question.
In industry, repeated failures have been experienced and are often caused by poor
practices in design and installation of reinforced composite pipelines, and also not
following the advice and recommendations of experienced pipe manufacturers or their
representatives, as available in their published design and installation manuals or
through consultation.
In addition, pipeline operators should be aware of the applicable regulatory
requirements for reinforced composite pipelines within the jurisdictions where they are
operating. This guide is not intended to describe or define the application of local
provincial or municipal government regulatory requirements that may apply to pipeline
projects.
Note that this guide does not endorse any proprietary products or processes.

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Contents
Overview .......................................................................................................................................... ii

1 Project Scope ................................................................................................................... 1-1

1.1 Materials .............................................................................................................. 1-1

1.2 Service Application............................................................................................... 1-1
1.3 Pipe Size ............................................................................................................... 1-2
1.4 Pressure Ratings ................................................................................................... 1-2

2 Review of Non-metallic Pipeline Failures ........................................................................ 2-2

2.1 Summary .............................................................................................................. 2-2

2.2 Common Incident Causes and Potential Solutions .............................................. 2-3
2.2.1 Installation Related .................................................................................. 2-3
2.2.2 Internal Corrosion of Steel Risers ............................................................ 2-6
2.2.3 External Corrosion of Steel Risers ............................................................ 2-7

3 Applications of Reinforced Composite Pipe .................................................................... 3-9

3.1 General ................................................................................................................. 3-9

3.1.1 Freestanding Pipe-in-Pipe ...................................................................... 3-11
3.2 Material Selection Analysis ................................................................................ 3-11
3.3 Sour Gas Applications ........................................................................................ 3-12
3.4 Selection Guideline ............................................................................................ 3-14

4 Design............................................................................................................................. 4-16

4.1 General ............................................................................................................... 4-16

4.2 Pipeline Stress Analysis Considerations (Stick Pipe) .......................................... 4-19
4.3 Pipeline Stress Analysis Considerations (Spoolable Pipe) ................................. 4-20
4.4 Design Pressure.................................................................................................. 4-21
4.5 Design Temperature .......................................................................................... 4-23
4.5.1 Thermal End Load .................................................................................. 4-25
4.6 Fluid Velocity ...................................................................................................... 4-25
4.7 Pipeline Risers .................................................................................................... 4-26
4.7.1 Risers for Reinforced Composite Pipelines- General ............................. 4-26

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 4.7.2 Risers for Stick Composite Pipe ............................................................. 4-27
4.7.3 Spoolable Composite Pipeline Risers ..................................................... 4-29
4.7.4 Spoolable Composite Pipeline Couplers ................................................ 4-30
4.8 Fluid Hammer..................................................................................................... 4-31
4.9 Vacuum .............................................................................................................. 4-31

5 Material Selection .......................................................................................................... 5-32

5.1 Reinforced Composite Pipe Materials ............................................................... 5-32

5.1.1 Stick Composite Pipe Products .............................................................. 5-32
5.1.2 Spoolable Pipe Products ........................................................................ 5-32
5.2 Material Selection for Metallic Couplers (Spoolable Pipe) ................................ 5-34
5.3 Materials for Risers ............................................................................................ 5-35
5.3.1 Reinforced Composite Pipe Risers ......................................................... 5-35
5.3.2 Metallic Pipe Risers ................................................................................ 5-35

6 Material Qualification .................................................................................................... 6-37

6.1 Design Stress/Pressure - Stick Pipe .................................................................... 6-37

6.2 Design Stress/Pressure- Spoolable Pipe ............................................................ 6-38
6.3 Additional Qualification Tests ............................................................................ 6-38

7 Installation ..................................................................................................................... 7-40

7.1 General ............................................................................................................... 7-40

7.1.1 Spoolable Pipe Installations ................................................................... 7-40
7.1.2 Stick Pipe Installations ........................................................................... 7-41
7.2 Pipe Transportation and Handling ..................................................................... 7-42
7.2.1 Stick Pipe ................................................................................................ 7-42
7.2.2 Spoolable Pipe........................................................................................ 7-44
7.3 Pipe Installation ................................................................................................. 7-46
7.3.1 Pipeline Trench Preparation .................................................................. 7-46
7.3.2 Road and River Crossings ....................................................................... 7-48
7.4 Thrust Blocks and Anchors ................................................................................. 7-49
7.5 Pipe-in-Pipe ........................................................................................................ 7-49
7.6 Metallic Tracer Wire .......................................................................................... 7-51

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8 Pipe Joining .................................................................................................................... 8-52

8.1 Stick Composite Pipe.......................................................................................... 8-52

8.2 Spoolable Pipe.................................................................................................... 8-55
8.3 Inspection Test Plan ........................................................................................... 8-56

9 Pressure Testing ............................................................................................................. 9-57

9.1 New Construction .............................................................................................. 9-57

9.2 Pressure Testing Repairs (Operating Pipelines) ................................................. 9-58

10 Operation ..................................................................................................................... 10-59

10.1 General ............................................................................................................. 10-59

10.2 Pressure ........................................................................................................... 10-59
10.3 Temperature .................................................................................................... 10-60
10.4 Pigging .............................................................................................................. 10-61
10.5 Chemicals ......................................................................................................... 10-61
10.6 Deactivation or Abandonment ........................................................................ 10-62

11 Reinforced Composite Pipelines Repairs ..................................................................... 11-63

11.1 Stick Pipe Repairs ............................................................................................. 11-63

11.2 Spoolable Pipe Repairs..................................................................................... 11-63
11.3 Excavation for Repairs ..................................................................................... 11-64

12 Operations Monitoring ................................................................................................ 12-65

12.1 Leak Detection ................................................................................................. 12-65

12.2 Cathodic Protection (CP) .................................................................................. 12-65
12.3 Pressure Cycles ................................................................................................ 12-65
12.4 Temperature Effects ........................................................................................ 12-66

13 Operations, Maintenance and Integrity ...................................................................... 13-67

13.1 Non-destructive Testing................................................................................... 13-67

13.2 Pressure Testing ............................................................................................... 13-67
13.3 Pipeline Risers .................................................................................................. 13-67
13.4 Pipe Cutouts ..................................................................................................... 13-67
13.5 Integrity Management ..................................................................................... 13-68

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14 References ................................................................................................................... 14-70

A.1 Abbreviations and Acronyms ........................................................................................... A-2

A.2 Reinforced Composite Pipe Options- Temperature (T)/Diameter (D)/Pressure (P)

Manufacturers Ratings Guideline .................................................................................... B-4

Figures
Figure 4-1 Pipeline Riser showing use of Sand Bagging for Support and Thrust Blocking.
Composite Riser Extends above Grade to Flange Transition to Steel Piping (Photo used courtesy
of Western Fiberglass Pipe Sales Ltd) ........................................................................................ 4-29
Figure 4-2 Spoolable Pipe Metallic Coupler (Wooden Beam to be removed for Installation)
(Photograph courtesy of FlexSteel Pipeline Technologies Ltd.) ................................................. 4-31
Figure 7-1 Typical Spoolable Reinforced Thermoplastic Pipe (RTP) Plough-In Installation Method
(Photograph courtesy of Flexpipe Systems) ............................................................................... 7-42
Figure 7-2 Typical Wooden Cradle Supports and Tie Down for Large Diameter Pipe Transport;
(Photograph courtesy of Fiber Glass Systems and Fiberglass Solutions Inc) ............................. 7-44
Figure 7-3 Spoolable Pipe Transport on Reel Trailer (Photograph courtesy of FlexSteel Pipeline
Technologies Ltd.) ...................................................................................................................... 7-46
Figure 7-4 Large Diameter Rigid Composite Pipe; Placement of Select Fill Bedding. (Photograph
used courtesy of Fiber Glass Systems and Fiberglass Solutions Inc) .......................................... 7-48
Figure 7-5 Spoolable Composite Pipe (SCP) - Unreeling Pipe for Placement in Pipeline Trench.
(Photo used courtesy of Fiberspar LinePipe Canada Ltd) .......................................................... 7-51
Figure 8-1 Provision of Shelters for Joining Composite Pipe; (Photograph courtesy of Fiber Glass
Systems and Fiberglass Solutions Inc) ........................................................................................ 8-55
Figure 8-2 Metallic Coupler Joining Sections of Spoolable Pipe (Photograph courtesy of FlexSteel
Pipeline Technologies Ltd.)......................................................................................................... 8-56

Tables
Table 3-1 Typical Thermal Properties for Composite versus Steel Pipes .................................. 3-10
Table 3-2 Typical Values of Surface Roughness of Composite and Carbon Steel Pipes ............ 3-10
Table 3-3 Allowable Pressures and Services for Spoolable Composite Pipe (SCP) and Reinforced
Thermoplastic Pipe (RTP) for Alberta ........................................................................................ 3-13
Table 3-4 CSA Z662-19 Allowed Pressures and Services for Reinforced Composite Pipelines in
Canada ....................................................................................................................................... 3-14
Table 4-1 Stick Composite Pipe Typical Physical Properties Comparison to Carbon Steel
Pipe1 .......................................................................................................................................... 4-19

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1 Project Scope
The scope of this document is to provide some best practices for users of reinforced
composite pipeline materials. The materials discussed within this guide include both
standard individual length rigid pipe (or stick pipe) and flexible reinforced composite
pipes (or spoolable pipe).

1.1 Materials
The use of the term reinforced composite pipe may mean different things to different
people as the term is often applied to many different types of non-metallic pipe. For the
purpose of this document, rigid individual length reinforced composite pipe will be
referred to as “stick pipe” while spoolable reinforced composite pipe will be referred to
as “spoolable pipe.”
Stick pipe generally refers to a fiberglass filament wound rigid pipe material with an
epoxy-based matrix binder.
Spoolable pipe generally refers to two general categories:
• Spoolable composite pipe (SCP) and

• Reinforced thermoplastic pipe (RTP).

SCP products use a bonded glass outer reinforcement and thermoplastic inner liner. RTP
products use an un-bonded outer reinforcement, such as glass fibre, steel strip/braided
cable or polymer fibre tape and thermoplastic inner liner.

1.2 Service Application

The service applications discussed are for production pipeline systems used by the
upstream oil and natural gas industry, located in Western Canada. These systems include
oil well multiphase flow lines, natural gas well gathering pipelines, oilfield water disposal
pipelines, and oilfield water injection pipelines. Other specialized applications may also be
relevant, such as large-diameter pipelines for hot water supply, underground firewater
distribution systems within plant sites or between base processing plants and remote
mining sites.
Currently gas transmission services are not approved for reinforced composite pipe by
CSA Z662-2019 but this limitation is currently under review and consideration by CSA
standards committee for possible revision in the next edition, scheduled to be published
in 2023. It should be noted that gas transmission pipelines are typically designed with 50-
year design life that must be considered if the pipe manufacturers qualification and rating
of their pipe products may be based on shorter lifetime.

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1.3 Pipe Size
Pipe sizes for stick pipe can vary from NPS 2” to NPS 48”—or larger depending on the
product manufacturer.
Spoolable pipe diameters available are NPS 2” to NPS 8” and are based on the product
manufacturer capabilities. Smaller diameter pipe may be available by special order. Note
that each product may have a different actual outside diameter, as spoolable pipe does
not have an actual standardized outside diameter.

1.4 Pressure Ratings

Pipe pressure ratings for stick pipe will vary by diameter and wall thickness. Typically,
smaller diameter pipes are available with higher pressure ratings up to approximately 20
MPa while larger diameter pipe, such as NPS 36”, are available at much lower pressure
ratings of 1 to 2 MPa.
For the various spoolable pipe products, different pressure-rated pipe products are
available, up to approximately 20 MPa. The pressure rating available will depend on the
product and pipe diameter involved, as not all spoolable pipe products are rated for the
same pressure. In some cases, pipe manufacturers may be capable of producing special-
sized or pressure-rated pipe that may not be listed in their standard product literature.

2 Review of Non-metallic Pipeline Failures

2.1 Summary
In 2007, an analysis of pipeline failure statistics was performed and presented at a
pipeline symposium held in Banff, Alberta. The analysis showed a relatively high incident
rate with reinforced composite pipelines. The analysis was updated in 2015 to reflect the
incident data from 2002 to 2014. Although overall incidents have dropped since 2002
stick fiberglass pipe and spoolable composite pipe incidents were found at a higher
incident rate than for steel pipe.
More recent data compiled by the Alberta Energy Regulator (AER) from 2015 to 2021
again shows that higher incident rates for stick fiberglass and spoolable composite
pipelines remain although some decline is evident for stick fiberglass pipelines.
The failure data reveals some of the more common and reoccurring stated causes of
failures, including:
• Rough handling during installation, need to avoid impact and kinking

• Corrosion of metallic risers and couplers

• Uneven support in ditch, or at risers/riser chute

• Harsh backfill without proper bedding material employed

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 • Unexpected failures under cyclic pressure conditions, surge flow, or water hammer

• Blockages – stuck pig, waxed off, hydrates

• Sensitivity of reinforcement materials to water intrusion

• Corrosion of steel reinforcement materials by water

• Failure to re-evaluate changing service conditions – inadequate Management of

Change (MOC) process

For more information on pipeline performance, the Alberta Energy Regulator (AER)
currently publish an annual Pipeline Performance Report2 that can be found at the
following website:
https://www.aer.ca/protecting-what-matters/holding-industry-accountable/industry-
performance/pipeline-performance

2.2 Common Incident Causes and Potential Solutions

2.2.1 Installation Related

Installation-related damage leading to pipe failures can result from several causes. Most
often, installation damage is unintentional and results from trying to install reinforced
composite pipelines using similar techniques and installations to those used for steel
pipelines. The reinforced composite pipe installation requirements generally do not differ
a lot from good installation practices for steel pipelines in terms of providing good quality
pipeline trench and soil properties such as providing pipe support and having low rock
content. However, reinforced composite pipe is more fragile than steel pipe and is more
likely to fail prematurely than steel due to installation-related deficiencies, such as poor
soil support, inappropriate anchoring, pipe impacts from frozen soil lumps or rocks and
improper backfilling practices.
In some cases, installation damage may be identified during the preliminary pressure test
and repaired. In other cases, damage may take much longer to develop into a failure
during operation. Two primary forms of damage that may take years to cause failure
include pipe abrasion (caused by sharp objects, such as sharp rocks rubbing against the
pipe, particularly in the case of vibration) and pipe impact (caused by dropping heavy
items such as frozen backfill or large rocks onto the pipe during backfilling). Damage to
the outer resin surface can lead to water ingress into the pipe wall resin/glass matrix and
cause loss of strength and failure over time and impact damage can cause localized
fracture or displacement of reinforcement materials causing a failure initiation site.
A primary damage mechanism is the lack of underground pipe support. If the soil support
to the pipe is not adequate or uniform, reinforced composite pipe could be damaged due
to uneven pipe settlement into the trench bottom. This may lead to the development of
excessive axial or shear stresses in the pipe body or at connections. Such soil instability
can be created during construction, if the soil is over-excavated at the base of the riser

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pipe-ends, resulting in inadequate soil support to the riser pipe. Therefore, special
attention must be paid to construction of risers to ensure proper support and protection
of the pipe.
Note:
Where the reinforced composite pipeline is connected to above-ground steel
headers or wellsite piping, the steel piping should be supported independently
of the pipeline risers. Anchoring to an above-ground steel piping system utilized
for supporting the pipeline risers is not recommended.
In some cases, differential movement between well anchored riser piping and the
connected pipeline has led to stress failure of fittings or pipe body at or near to the riser.
Therefore, such below-ground connections at risers must be designed and installed with
due care.
For spoolable pipe risers, an underground structural steel support is often used to secure
the riser; however, this type of support structure is not intended to support above-
ground steel piping. The transition from the exit of the riser chute to the trench bottom
should be on undisturbed ground that may require use of a riser extension support from
the chute base to the undisturbed ground.
Another area of concern for stick pipe is pipe joint integrity. As a general rule, pipe joints
are made from either threaded mechanical connections on smaller diameter stick pipe
(<12 inch), or adhesive bonded bell and spigot on larger diameter pipe. In some cases, for
larger diameter stick pipe, a butt and wrap joint using manual application of glass matt
and resin is employed.
Currently there is no proven technology for non-destructive examination (NDE) of these
joints before placing them into service. Therefore, the qualifications and competencies of
joining personnel—along with strict adherence to the qualified joining procedure—should
be required and is a key success factor. This is a challenging area to manage for pipeline
construction projects, especially for installers whose pipeline installation experience is
based primarily on steel pipelines.
Similarly, each spoolable pipe product has different joining coupler designs, which are
mainly mechanical in nature and rely on strict adherence to installation procedures and
qualified personnel. In some cases, manufacturers allow field installations of their
proprietary connections by trained construction contractors.
The manufacturers of reinforced composite pipe products provide installers with training
and certification. For both stick pipe and spoolable pipe projects, end users should ensure
the installation personnel on projects have a valid training certificate as currently
specified by CSA Z662-2019.
With spoolable pipes, a great deal of care should be taken to not twist or over-torque the
pipe body during placement. This is especially important during wintertime construction
when the inner liner material is less ductile and more brittle than when installed at
warmer temperatures. Over-torquing could cause cracking or microcracking to develop in

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the outer reinforcement structure or inner liner that may result in failure under pressure
during pressure testing or later while in service.
Example of Over-Torque Damage:
Over-torque damage could result from attempting to stretch or force the reinforced
composite pipe (with ends that already have flanges installed on them) to mate-up to the
fixed risers or piping in situations where the above-ground risers or piping are installed
before constructing the pipeline.
With spoolable pipe, kinking or damage to the glass winding pattern spacing can occur
during installation and requires careful unreeling and vigilance during construction. This is
especially important if heat is applied to the pipe reel during winter construction. Non-
uniform heating on the reel must be avoided as it may cause kinks to form where the pipe
becomes more pliable in heated areas but remains much stiffer in colder areas of the
reel.
Therefore, any heating of spoolable pipe reels must be done carefully and in accordance
with the manufacturer’s procedure. Caution should be exercised to not overheat the pipe
above its specified maximum temperature limit.
Where spoolable pipes or reinforced composite pipes are installed as a free-standing
pipe-in-pipe through an existing steel conduit pipe, support of the spoolable pipe where it
enters and exits that steel pipe is of primary importance. The steel conduit pipe will
normally be installed in a solid and settled area of ground. However, the area where the
composite pipe exits the steel conduit pipe is subject to new and varying soil settling that
could lead to a failure at the entry/exit areas of the conduit pipe. Furthermore, any
intermediate bell-hole excavation locations that connect two adjacent pull sections
through existing conduit pipe may cause differential soil settling and excessive shear
stress to develop within the spoolable pipeline.
Free-standing pipe entry and exit areas, at the ends of the steel conduit pipe are prone to
reinforced composite pipe movements due to unrestrained thermal expansion of the
composite, surge flow or cyclic operating pressure conditions that may cause the free-
standing pipe to laterally deflect and, in some cases, buckle in unstable disturbed soils. In
some cases, a steel casing for the free-standing pipe interconnection area is provided to
prevent deflection of the composite.
For installation of reinforced composite pipe inside existing pipe, either pull-in or push-in
methods are used. It is critical to prepare an installation procedure that does not exceed
the maximum tensile or compressive loading of the pipe. Exceeding the maximum
specified load can result in pipe damage. The condition of the outer conduit pipe must
also be assessed, typically by pigging, to size the internal diameter and detect any other
features such as fittings or dents that may lead to damage during installation.
It is also important to ensure the spoolable pipe can be fed into and out of the conduit
pipe without the spoolable pipe being kinked, scraped, or gouged and that the minimum
bending radius is observed. Steel pipe ends should be radiused and approach chutes

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constructed if necessary. It may also be necessary to install guides or centralizers on the
composite pipe to prevent damage from abrasion.
The need for internal and external corrosion protection for metallic joining couplers used
for spoolable pipes should also be provided, based on the corrosiveness of the service
fluid and general soil conditions. Application of protective coating and cathodic
protection (CP) must also be considered.

2.2.2 Internal Corrosion of Steel Risers

In some cases, the use of a carbon steel or corrosion resistant alloy pipe riser for
reinforced composite pipelines is preferred by some end users. The use of metallic pipe is
usually to provide increased strength, damage resistance or fire resistance for the pipe
riser section.
Since reinforced composite pipelines are often installed to transport highly corrosive
service fluid, internal corrosion of the steel pipe riser should be considered a threat and
mitigated. Internal corrosion of steel piping that is associated with reinforced composite
pipelines is one of the leading causes of failure.
In some cases, chemical inhibition may be a consideration to protect the steel riser
piping, but the possible effects of the chemical on the reinforced composite pipeline
material must also be considered.
Most often, internal corrosion mitigation for carbon steel is accomplished by using
internal plastic coatings that are shop-applied beforehand. At times, specialty coated, and
welded insert fittings are used to fabricate risers using coated pipe sections.
A couple of factors to consider for use of plastic coatings with risers are the diameter and
design of the riser. The use of NPS 2 diameter pipe is not recommended since generally
this is too small to successfully apply internal coating.
The use of an appropriate internal coating product, combined with a quality application
by an experienced coating application expert, is highly recommended. There are several
internal pipe coating application contractors available within the industry who specialize
in this type of coating application and should be utilized for riser coatings. Industrial
coating manufacturers should also be consulted for their recommendations of suitable
internal coating materials and applicators. Using a coating with adequate temperature
and chemical resistance is also of key consideration. Epoxy-based coatings are most often
specified in typical thickness range of 300-400 microns (12-16 mils).
Internally coated steel pipe risers should also be designed with suitable flanges or fittings
that provide internal access for both weld area grinding and the coating application, as
coatings may fail prematurely if weld beads are left rough or if weld splatter exists.
Where access for weld grinding in pipe spools is not practical, the use of alternate
welding processes that develop a smoother internal weld bead, such as MIG, should be
considered. NACE SP01783 provides information on preparing weld surfaces for internal
coating application.

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Diameter differences between reinforced composite piping and the riser piping
(particularly when the riser piping diameter is smaller) should be evaluated in the coating
selection step regarding the coating’s erosion resistance properties.
Where pipelines require pigging, the effects of diameter variances between pipeline and
riser piping should be considered. Reinforced composite pipe products have unique
internal diameters and are not standardized to steel nominal diameters so suitable
diameter pigs should be selected.
Where possible, gradual diameter changes should be used as more aggressive changes
may lead to premature coating failure (e.g., NPS 4 piping reduced to a 2" valve assembly).
Furthermore, flanged connections versus welded connections should be considered for
ease of coating smaller pipe sections and grinding weld areas for surface preparation.
Cost is a factor to be considered here, as flanged connections are normally more
expensive than welded connections.
The field application of internal coatings is not normally recommended due to the
inability to adequately clean the steel pipe and apply uniform coatings under typically
adverse field conditions. Therefore, steel pipe riser internal coating applications should be
performed in a specialized coatings application shop.
It is also common to install reinforced composite pipe risers and to transition to steel pipe
just above ground level with a flange. This practice is discussed in more detail in the
design and installation sections 4.0 and 7.0 of this guide.
In some cases, corrosion-resistant alloy (CRA) piping—such as stainless-steel alloys—has
been used for risers; however, an appropriate alloy material that is suitable for the
service fluid and operating temperature should be carefully selected. The alloy selection
and connecting method between the alloy riser piping and the reinforced composite pipe
should be discussed with the reinforced composite pipe manufacturer.

2.2.3 External Corrosion of Steel Risers

External corrosion of steel risers is also identified as a common cause of failure. Where
steel risers are employed in conjunction with reinforced composite pipelines, suitable
external coatings such as liquid epoxy, shrink sleeves or tape wraps rated for the current
and future service temperatures should be applied. To supplement the protective
coating, spot CP should also be installed—usually with a sacrificial anode. It is specified in
CSA Z662-2019, that CP installed on metallic risers connected to reinforced composite
pipe shall be monitored.

2.2.4 External Interference (Contact Damage)

Damage by ground disturbance is identified as a cause of service failures for reinforced
composite pipelines. In some cases, this is a result of a lack of knowledge regarding the
accurate location of underground pipelines or not following industry-recognized ground
disturbance procedures.

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It is important—and a CSA Z662-19 pipeline code requirement—that all reinforced
composite pipelines be installed with a suitable tracer wire to allow accurate use of
pipeline location equipment. Tracer wire may not be required for some spoolable pipes
that utilize either metallic wire or strip reinforcements, however the manufacturer should
be consulted for clarification on this requirement.
In older oil fields, pipelines may have been installed without tracer wire. In such cases,
careful analysis and caution should be exercised—using information such as drawings or
installation files—to best determine pipe location. Again, proper ground disturbance that
avoids the use of mechanical excavation near buried facilities can help minimize this risk.
Above-ground pipeline markers are also required and recommended to help increase
awareness of underground pipelines and to help locate pipelines.
In cases where the pipe location is not accurately known, there may be no choice but to
perform careful hand or hydro-vacuum excavation to locate the pipeline. Audible sound
probes may also be considered to locate the pipeline. Use of steel probes pushed through
the soil to locate pipe should be done very carefully as these can damage reinforced
composite pipe if they have sharp-pointed ends or are driven into the pipe wall with
excessive force. See Section 11.3.

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3 Applications of Reinforced Composite Pipe

3.1 General
Reinforced composite pipe is used by the oil and natural gas production industry for
various pipeline services. Typically, it is used for more highly corrosive fluid applications.
Services include the following applications:
• Oil, natural gas, and multiphase fluid pipelines.

• Natural gas gathering production pipelines and fuel gas supply pipelines.

• Oilfield water pipelines (produced waters and fresh waters).

In most cases, reinforced composite pipelines are initially considered and installed to
provide longer-term operating benefits to the pipeline operator. Initial material costs
will vary given the prevailing market conditions and price fluctuations for both steel and
composite materials. In some cases, the installed cost may be lower compared to steel
pipelines, but relative cost usually depends on the pipe product and the pipeline
installation specifics.
Regardless of the initial pipe material and installation costs, the potential for reduced
operating cost is a primary consideration in the use of reinforced composite pipe.
Where possible, economic comparisons between reinforced composite pipe and carbon
steel pipe should be based on total life cycle costs that consider the initial capital costs
and the operating and maintenance costs over the life of the pipeline. Consideration
should also be made on how to monitor the pipeline integrity over its life and the
associated costs.
Internal corrosion resistance to corrosive agents within the service fluid, such as wet
carbon dioxide and sodium chloride, is one of the primary benefits of reinforced
composite pipe material and an important means of reducing operating costs. Steel oil
and natural gas production industry pipelines generally require various measures to
control internal corrosion, such as the injection of a chemical corrosion inhibitor on a
continuous or batch-basis, internal thin film organic coatings and the use of pigs to
remove stagnant water and debris. Such mitigation methods represent additional
operating costs that will last over the life of the pipeline.
In some cases, chemical corrosion inhibition treatments are not required, but in other
cases, due to the presence of remaining steel facilities such as risers or inter-connected
steel pipelines, internal corrosion mitigation is still required. See Sections 4.1, 5.1 and
10.5 for further information on chemical compatibility.
In some cases, reinforced composite pipe is installed to provide increased resistance to
the buildup of deposits such as paraffin waxes or scales on the pipe internal surface that
can reduce flow and increase pressure drop. This benefit is derived from the smoother
pipe surface, the lower thermal conductivity, and higher specific heat capacity of

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reinforced composite pipe compared to steel pipe. Table 3-1 provides typical thermal
properties of reinforced composite versus carbon steel pipes.

Table 3-1 Typical Thermal Properties for Composite versus Steel Pipes

Material Thermal Conductivity, W/mK Specific Heat, J/kg K

Steel Pipe 50 450

Composite Pipe 0.4 1670

Internal corrosion of carbon steel pipe in water services can lead to the significant
buildup of scales or fouling deposits. Such buildup may have a significant effect on pump
pressure drop performance through the pipeline and lead to increased power
consumption or decreased injection-well performance.
The internal surface of reinforced composite pipe is only slightly smoother than new
steel pipe; however, the surface finish of new steel can degrade and become much
rougher over time due to corrosion and/or scale buildup.
Pipes with polyethylene inner liners benefit from the inherent tendency of polyethylene
to resist adhesion to other materials that leads to resistance to scaling or fouling by
solids.
Table 3-2 provides some of the typical published values of surface roughness and the
Hazen Williams flow coefficient for reinforced composite pipes compared to carbon
steel pipe. The typical values given in Table 3-2 are for general information only. For
surface roughness values for individual pipe products the pipe manufacturer’s product
specifications should be consulted and their specified values used for individual project
evaluations.

Table 3-2 Typical Values of Surface Roughness of Composite and Carbon Steel Pipes

Material Surface Roughness, mm Hazen Williams Flow

Factors

Steel Pipe, new 0.040 130-140

Steel Pipe, lightly rusted 0.400 100

Steel Pipe, very rusted or scaled 3.400 60-80

Composite Pipe 0.005 150

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 3.1.1 Freestanding Pipe-in-Pipe
Reinforced composite pipe is also commonly installed as a smaller diameter pipeline
inside an existing steel conduit pipeline that has failed or is expected to be in poor
condition due to corrosion. This method of pipe installation is also referred to as slip-
lining or use of a free-standing pipe-in-pipe. Use of this method may be less costly than
conventional replacement of the pipeline or running an internal inspection smart pig
(ILI).
This approach can also offer environmental advantages given the smaller footprint it
creates as excavations are only required for access at the ends of pipeline sections
where the reinforced composite pipe is inserted or exits the conduit pipe. Also, the
existing pipeline right-of-way can be utilized, and no additional right-of-way is required,
thereby further minimizing landowner impact.
However, in the event of the reinforced composite pipe failing inside a damaged conduit
pipe, knowledge of the slope of the land and/or locations of discontinuities in the carrier
pipe are important factors to allow determination of where any fluid may come to
surface. Further, the removal of the reinforced composite pipeline and spilled product
within the conduit pipe may become a difficult task.
The areas where the conduit pipe is removed to allow installation of the inner pipe
should be located in suitable areas that are less sensitive and away from streams and
bodies of water, etc. To provide further containment, a secondary metallic casing sleeve
may be installed over the connection areas. This allows monitoring and flow control to
be more focused at the end points of the pipeline.
Therefore, a review of bell-hole locations and any known sections of the conduit pipe
that may have been permanently removed for installation of the composite pipe
should be documented and readily available in the event of a failure. The conduit pipe
should be electrically bonded for pipe location tracing.
Where the conduit pipe is continuous, the installation of vents on the conduit pipe may
also be considered at various locations.
Use of GPS coordinates is recommended to keep track of the bell-holes or removed
sections of conduit pipe.

3.2 Material Selection Analysis

The final selection of suitable pipeline materials requires extensive analysis on a project-
by-project basis and is well beyond the scope of this document. A thorough
understanding of the intended service conditions, including the expected normal
operating conditions and also any upset conditions that could occur, is required. Future
field development plans also need to be considered as are any planned changes in
service conditions, such as increases in temperature, static pressure, cyclic pressure,
pulsating pressure, production rates, or hydrogen sulphide (H2S) levels that could
change or occur in the future development of the field. These new conditions may not

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 be suitable or may present increased risk for the use of reinforced composite pipeline
materials. Design life is another critical parameter in determining the strength and type
of material selected. More detailed coverage of the design aspects of using reinforced
composite pipe for pipelines is in Section 4.
Some key conditions that should be understood when selecting pipeline materials
include:
Steady-state conditions:
• Service fluid compositions, such as corrosive products, sand, wax, etc.;

• Operating flow rates,

• Operating pressure range including the amplitude and frequency of pressure cycles,

• Surge pressure flow conditions in two phase fluid and single phase fluid pipelines,

• Operating temperatures,

• Pumping conditions including pump start/stop parameters,

• Pump pulsation control.

Upset operating conditions

• Transient flow,

• Start-up/shut down characteristics (e.g., valve closure timing, electrical grid power
bumps),

• Pigging requirements (due to liquid or wax buildup),

• Availability and reliability of power source for cathodic protection system.

Where routine high-cyclic pressure operation is possible for the pipeline in question, this
aspect should be carefully considered and discussed with the pipe manufacturer prior to
material selection and accounted for in the pipeline design as specified by CSA Z662-19.
CSA Z662-19 specifies service to be cyclic when the operating pressure regularly cycles
more than 20 per cent of the pipeline maximum design pressure.
Associated operating conditions, such as pigging requirements, hot-oiling, and the use
of additive chemicals or well stimulation chemical exposures must also be understood
and included in the materials selection.
The pipeline terrain conditions must also be well understood as described in Section 4.

3.3 Sour Gas Applications

For reinforced composite pipe products that utilize metallic reinforcements, the
suitability for sour service fluids, including natural gas, oil, and water, should be

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 reviewed by end users in consultation with the manufacturer. This is required due to the
permeation of H2S and other gases through the liner layer and contact with the metallic
reinforcement layer and the potential for corrosion or sulphide stress cracking (SSC) of
the reinforcement.
For pipelines located in Alberta, the Alberta Energy Regulator (AER) Directive 0564 and
Manual 0125 provide limits to various non-metallic pipe products regarding allowable
H2S and pressures and application requirements. See Table 3-3.
Canadian Standard Association (CSA) standard Z662-19 for oil and natural gas pipelines
in Canada specifies limits for pressure for some services fluids and H2S limits for non-
metallic pipe products. See Table 3-4.
Metallic components installed in sour service pipelines are required to meet CSA Z662-
19, Clause 16.

Table 3-3 Allowable Pressures and Services for Spoolable Composite Pipe (SCP) and Reinforced
Thermoplastic Pipe (RTP) for Alberta
(Based on CSA Z662-19 and the Alberta Energy Regulator (AER) Pipeline Regulations AR 91/2005, Directive 056 and
Manual 012. Note the user should check for any updates from CSA and AER)

Pipeline
Service1 Allowable H2S Content Allowable Pressures
Product
OE, SW, Any amount Any pressure to maximum rating
FW, CO, LV of pipe for that service condition
Fiberspar™
NG, FG 10 mol/kmol maximum H2S content 9930 kPa maximum (CSA Z662
FSLP
(AER limit) but also 50 kPa H2S partial limitation)
pressure maximum (CSA Z662 limit)
OE, SW, H2S content limit of 3.0 mol/kmol Any pressure to maximum rating
FW, CO, LV (AER limit) of pipe for that service condition
Flexcord™ FCLP NG, FG H2S content limit of 3.0 mol/kmol (AER 9930 kPa maximum (CSA Z662
limit) but also 50 kPa H2S partial limitation)
pressure max (CSA Z662 limit)
OE, SW, Any amount Any pressure to maximum rating
FW, CO, LV of pipe for that service condition
Flexpipe™ FPLP NG, FG 10 mol/kmol maximum H2S content 9930 kPa maximum (CSA Z662
(AER limit) but also 50 kPa H2S partial limitation)
pressure maximum (CSA Z662 limit)
OE, SW, Any amount FPHT 301: maximum 4960 kPa
FW, CO, LV FPHT 601: 9930 kPa (AER
Flexpipe™ High
limitation)
Temperature
NG, FG 10 mol/kmol maximum H2S content 9930 kPa (CSA Z662 limitation)
FPHT
(AER limit) but also 50 kPa H2S partial
pressure maximum (CSA Z662 limit)
OE H2S partial pressure limit of 5.5 kPa maximum 6620 kPa (AER
Wellstream
(AER limit) limitation)
FlexSteel™
SW, FW, H2S partial pressure limit of 5.5 kPa Any pressure to maximum rating
WSLP
CO, LV (AER limit) of pipe for that service condition

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 Pipeline
Service1 Allowable H2S Content Allowable Pressures
Product
NG, FG 10 mol/kmol maximum H2S content maximum 6620 kPa (AER
(AER limit) but also H2S partial limitation)
pressure limit of 5.5 kPa (AER limit)
OE, SW, FW, If zero H2S Any pressures to maximum
CO, LV rating of pipe for that service
condition
NG, FG If zero H2S 9930 kPa maximum (CSA Z662
limit)
Note 1: NG – Natural Gas, OE – Oil Effluent, SW- Salt Water, FW – Fresh Water, CO – Crude Oil, LV – Low Vapour
Pressure, FG – Fuel Gas

Table 3-4 CSA Z662-19 Allowed Pressures and Services for Reinforced Composite Pipelines in Canada

Pipeline Type Service1 Allowable H2S Content Allowable Pressures

OE, SW, FW, Any amount Any pressure to maximum
Reinforced Composite CO, LV rating of pipe for that
Pipe service condition
NG, FG 50 kPa H2S partial pressure 9930 kPa maximum design
(Stick, SCP, RTP) maximum based on pipeline pressure
design pressure.
Note 1: NG – Natural Gas, OE – Oil Effluent, SW- Salt Water, FW – Fresh Water, CO – Crude Oil, LV – Low Vapour
Pressure, FG – Fuel Gas

3.4 Selection Guideline

A recommended selection guideline table is provided in Appendix B for information only
and is based on manufacturers’ published product specifications.
For the selection of reinforced composite pipes in particular, strict attention should be
given to the combination of service pressure and temperature including upset operating
conditions. Each pipeline environment includes a unique combination of temperature,
pressure, stress and chemical factors and should also be considered. The combined
effects of these factors on the reinforced composite pipe should be determined based
on the manufacturer’s recommendations—and additional testing if required—in the
selection of a suitable material.
Reinforced composite pipe manufacturers usually qualify their products based on long-
term tests using water at various stress levels and temperature conditions. However,
prudent pipeline design may warrant that some de-rating factors be applied as
determined on a project-by-project basis by the project design engineer. Therefore, the
service conditions, installation conditions and design factors should be discussed and
determined by the designer for each situation. This should be done in conjunction with
input from the pipe manufacturer’s technical staff.

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CSA Z662-19 provides the minimum service fluid design factors that are specified to
determine the pipeline design pressure (refer to Table 4-2 in Section 4 of this guide for
an overview of the minimum service fluid factors).

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4 Design

4.1 General
As stated in Section 3, reinforced composite pipeline design requires a thorough
understanding of the intended service conditions on a per-project basis that includes
the expected normal operating conditions, future operating conditions, and any
associated or upset operating conditions. Projects undertaken without due care and
awareness of the differences in material properties compared to steel are not likely to
succeed. Therefore, short- and long-term success requires extra attention to various
aspects at the pipeline design stage, several of which are highlighted in this section.
Success with reinforced composite pipelines usually involves aspects of design that go
beyond a simple review of pipe pressure rating and normal operating conditions, to
include the following:
• Selection of a suitable pipe product.

• Assessment of soil conditions to ensure provision of adequate pipe support and

prevent pipe damage due to excessive pipe stresses caused by settlement, especially
at riser locations.

• Assessment of fluid flow regimes to ensure high surge two-phase or single-phase

cyclic flow conditions are not prevalent that could cause over stress impact damage
to the pipe especially at end point risers or other changes of direction fittings,

• Riser material and design configuration,

• For SCP and RTP pipelines, metallic coupler material selection,

• Selection and qualification of a competent pipeline installation contractor.

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Recommendations:
The selection of a competent installation contractor is a key to success with reinforced
composite pipelines. The unique properties and special installation, joining, and
handling requirements are much different from installation of standard steel pipelines
and require specially qualified, trained personnel for installation. The installation
contractor should have quality control systems and procedures in place that apply to
reinforced composite pipelines.
Reinforced composite pipe manufacturers have design and installation manuals and
technical representatives that are made available to assist end users. Throughout the
design process it is recommended that the pipe manufacturer be consulted and
requested to provide their technical review of the service application and installation
conditions, and to provide input based on their product experiences. Note: reinforced
pipe manufacturers typically update manuals and issue bulletins on a regular basis. It is
critical that the installation contractor uses the most current version.
Some key design parameters that should be considered include determining:
• An accurate service fluid composition.

• Operating pressure range including the amplitude and frequency of pressure cycles,
surge flow pressure conditions, and flow velocity.

• Operating temperatures.

• Upset operating conditions.

• Pump operation conditions including pump start/stop effects.

• Pump pulsation control.

• Fluid hammer and surge flow conditions, especially in two-phase flow regimes, and
their effects.

• Special requirements for pipe risers or lateral branch connections where elevated
pipe stress conditions exist due to operating temperature and fluid flow.

• Monitoring and inspection.

Operating conditions should also be understood and included in the design analysis.
Discussion with the pipe manufacturer’s technical staff can provide guidelines and
technical review of the application and is strongly recommended.
Several of these conditions to review include:
• Pigging

• Hot-oiling

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• Additive chemicals

• Well stimulation chemicals

• Pressurization/depressurization (start-up/shut down procedures)

The effects of additive chemicals such as wax solvents that contain benzene and/or
toluene, acidic well stimulation chemicals and methanol may prove harmful to the pipe
material and must be carefully considered. In cases where the chemical exposure is very
short duration or added at low concentration, the harmful effects of chemicals may be
reduced. Pipe manufactures publish chemical resistance charts to assist in this regard
and should be consulted for recommendation on acceptable chemical exposures.
As well, the pipeline terrain conditions should be understood and include a review of
• General soil stability, throughout the pipeline but especially at riser locations,

• Existence of muskeg sections,

• Road, water or railway crossings,

• General rock conditions, and

• Overall soil characteristics.

In terms of appropriate soil conditions for reinforced composites, industry standards—

such as ASTM D 38396 and AWWA M457—can provide guidance. The pipe
manufacturer’s technical manuals will also include information on required soil
conditions, compaction, and other design information.
The pipeline trench bedding conditions must provide a uniform firm and stable support
for the pipe. Often bedding material such as sand or clean soil will need to be imported
to provide rock free conditions or stability. In some cases spray foam or sand bags are
used.
At transitions from stable support to little soil support, differential pipe settlement may
occur causing pipe damage.
CSA Z662-19 specifies rock-free bedding material around the pipe for 150 mm distance.
Pipe products have varied impact damage capability and further guidance on impact
resistance may be obtained from the manufacturer.
Where the trench is over-excavated, a foundation can be provided using SC 1 or SC 2 soil
classification material per ASTM D 3839. For severe conditions such as muskeg or very
wet areas, a special foundation design may be necessary.
Bending stress can be controlled by adhering to the bend radii above the minimum
bending radii limits published by the pipe manufacturer. The allowed bend radius will
vary for different pipe products and diameters. Allowable minimum bending radius may
have to be increased when installation takes place in sub-zero temperatures based on
pipe manufacturers procedures.

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 Where the pipeline topography has many elevation variations or requires changes of
direction, the use of fittings may be required for stick pipe installation, since it cannot be
bent in the field like steel pipe.
Unlike steel pipe, stick composite pipe is anisotropic, therefore its mechanical
properties—such as tensile strength or modulus of elasticity—are directionally
orientated (as a result of the fibre reinforcement winding orientation). As a result, stick
composite pipe has a unique modulus of elasticity for hoop and axial orientations with
the pipe having a much higher hoop strength than axial strength. This anisotropy must
be considered when designing road or water crossings using horizontal directional
drilling (HDD) techniques, which require pulling the pipe through the bore. Installation
procedures and equipment for installing pipe through bores should monitor pulling
weights or include load-limiting devices in the pull head equipment, so that tensile load
limits are not exceeded.
Table 4-1 provides a comparison of pipe properties for a typical stick composite pipe as
compared to a typical standard carbon steel pipe. Data in Table 4-1 is provided for
information and comparison purposes only, as it contains approximate typical values
that should not be used for design purposes. Only the pipe manufacturer’s specified
mechanical property values should be used for design purposes.

Table 4-1 Stick Composite Pipe Typical Physical Properties Comparison to Carbon Steel Pipe 1

Property Rigid Composite Pipe Carbon Steel Pipe Grade 240

Tensile Strength, MPa 138 240

Design Stress, MPa 125 240

Modulus of Elasticity, GPa Axial- 13 207

Hoop- 25

Coefficient of Thermal Expansion, Axial 2.0 x 10-5 1.4 x 10-5

mm/mm/0C 2
Hoop 1.1 x 10-5
Note 1: Values in Table 4-1 are typical only and are provided for comparison, not intended to be used for pipeline
design. Designer should verify pipe properties with the manufacturer.
Note 2: Depends on epoxy resin content and glass fibre orientation. Hoop and axial values differ.

4.2 Pipeline Stress Analysis Considerations (Stick Pipe)

The stress analysis for reinforced composite pipelines is specialized and requires
awareness and modification to the standard stress analysis methods as employed for
steel pipelines.
A significant difference to consider between rigid composite and steel piping is that
composite piping uses fittings that have higher rigidity and significantly thicker wall
thickness than the inter-connected pipe.

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 Generally, for smaller diameter oilfield pipelines, e.g., NPS 2-6, a formal stress analysis
may not be required. As the pipe diameter increases, pipe systems involving fittings at
risers, tend to become less flexible and stress intensification at fittings such as elbows
and tees increases. Therefore, for larger diameter pipelines, high temperature pipelines
or complex above-ground piping systems, a more formal stress analysis may be
performed using stress analysis software. This question however requires judgment by
the designer and each case should be considered on its own merit and reviewed with
the manufacturer. In performing stress analysis generally, the pressure-induced stresses
plus other loadings on buried piping are considered.
The general requirement is that the hoop stress and the axial stress are considered
separately, and the stresses are within the published hoop and axial stress limits of the
reinforced composite pipe. Beam bending stresses must also be within manufacturers
published limits. Again, note that these properties cannot be generalized and are
specific to individual pipe and fitting products.
Where the axial stress is compressive it can be checked for axial buckling. The
development of axial stresses in underground pipe is normally based on various factors
such as hoop stress/expansion causing axial tensile stress where the pipe is restrained,
thermal expansion or contraction where the pipe is restrained, and beam bending
stresses that relate to the amount of pipe settlement and soil support being non-
uniform.
As shown in Table 4-1, the coefficient of thermal expansion in the axial direction is
higher for stick fiberglass pipe than for steel pipe, however the thermal expansion loads
are much lower compared to equivalent sized steel pipe. This is due to the much lower
modulus value of reinforced composite stick pipe. Section 4.5.1 provides additional
information on thermal end load.
Any loads imposed from attached steel piping, risers, or valves should be considered
and should not excessively load the composite piping. The attached steel facilities
should be supported independently from the composite pipeline.

4.3 Pipeline Stress Analysis Considerations (Spoolable Pipe)

Spoolable composite pipe products will vary in the amount of expansion or contraction
under pressurization. Typically, under high pressures and depending on the pipe
product, the pipe may tend to axially contract. Where the pipe is buried, normal soil
restraint should prevent excessive movement but where pipe is not backfilled, such as
at any exposed risers, precautions are required to provide support for contraction or
expansion loads under operation. It may be advisable in some cases to install the pipe
with some slack or other method to allow for movement to reduce stress
concentrations.
Where long unrestrained pipe sections exist, such as in a non-backfilled trench or for a
pull-through liner, special provisions may be required due to pipe contraction stress and
should be discussed and reviewed with the manufacturer’s technical staff.

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 Where spoolable pipe passes around bends, if positioned against the trench wall the
pipe may contract when under high pressures and cause damage. This behavior must be
considered and incorporated into procedures, based on review with the manufacturer.
Pipeline trench requirements for spoolable pipe are similar to stick composite pipe. In
general, spoolable pipes are more flexible and somewhat less sensitive to settling and
shear stress than stick composite pipe. However, spoolable pipes can be damaged by
rocks placed in contact or very near to the pipe, which may work through the soil to
contact the pipe during service and cause wear damage and eventual failure.
As stated above for stick composite pipe, loads imposed from attached steel piping,
risers, or valves should be considered and should not excessively load the composite
pipeline pipe due to soil settlement. The attached steel facilities should be supported
independently from the composite pipeline.
In some cases fixed riser piping does not provide adequate flexibility at the transition to
the composite pipeline to compensate for settlement or other pipe movements, leading
to damage of the composite at the transition fitting.

4.4 Design Pressure

Reinforced composite pipeline design generally starts with determining the maximum
allowed design pressure, which is based on the manufacturer’s maximum pressure
rating (MPR) or the maximum operating temperature for the pipeline. This is the
qualified pressure rating based on the manufacturing standards specified in CSA Z662-
19. Section 6 of this guide discusses pipe qualification methodology in more detail.
The pipeline designer should consult and use the manufacturer’s published design
information to the extent available but should also determine any unique circumstances
for the project, such as
• Highly cyclic pressures, surge flow pressures, pulsation

• Temperature excursions,

• Pigging, and

• Vacuum excursions.

In some cases, additional design factors are required and should be applied on a project-
by-project basis.
Once the reinforced composite pipe MPR is known, service fluid factors are applied to
determine the maximum pipeline design pressure allowed. Table 4-2 gives the minimum
service fluid factors as specified in CSA Z662-19. Additional design factors are required
where cyclic pressure conditions exist, as determined by the project engineer and
applied in addition to the minimum service fluid factors specified by CSA Z662-19.

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Equation 1 is based on the allowable design pressure formula specified by CSA Z662-
2019 and provides the basis to determine pipeline design pressure for reinforced
composite pipelines.
Design Pressure = MPR x Ffluid x Fcyclic x Fproject (Equation 1)
where:
MPR = maximum pressure rating
Ffluid = service fluid factor, CSA Z662
Fcyclic = cyclic pressure service factor to be specified by the manufacturer for cyclic
pressure service conditions.
Fproject = additional project design factor where determined by Project Engineer

Table 4-2 CSA Z662-19 Service Fluid Factors (Ffluid)

Pipe Type Category Gas Multiphase. Oilfield

LVP liquids Water

Stick Pipe Stick Composite- API 0.67 0.80 1.0

Monogram

Stick Pipe Stick Composite 0.60 0.72 0.8

No API Monogram

Spoolable Pipes SCP 0.67 0.80 1.0

RTP Type 1 0.67 0.80 1.0

RTP Type 2 0.67 0.80 1.0

RTP Type 3 0.67 0.80 1.0

For some spoolable pipe products, the service fluid factor specified in CSA Z662-19 may
already be included in the manufacturer’s MPR—designers should determine if this is
the case for the pipe product involved.
In pipelines where continuous and routine pressure cycling exists, such as that caused
by water injection pump start/stops, an extra design factor should be applied in
consultation with the pipe manufacturer. The cyclic design factor is normally specified
by the manufacturer based on their product testing. If no factor is specified, then a
default factor of 0.5 is specified by CSA Z662-19.
Users should also consider, and discuss with the manufacturer, the cyclic component
experienced where pipelines start and stop service repeatedly. Pressure fluctuation

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 from zero to maximum working pressure may be encountered and must also be
considered as cyclic service.
The importance of properly considering cyclic pressure cannot be over-emphasized.
Cyclic pressure is believed to be a predominant cause of unexplained pipe body failures.
CSA Z662-19 currently defines severe cyclic as pressure cycles in excess of ±20 per cent
of the pipeline design pressure but this definition is under review and subject to change,
therefore later edition CSA Z662-2023 should be reviewed following scheduled
publication in 2023. The various fiberglass and composite pipe manufacturing standards
currently referenced in CSA Z662-2019 also have limitations on cyclic operation that
should be considered.
Other industry pipe standards including ASTM D29968 and ISO 146929 for stick pipe and
API 15S10 for spoolable composites, also contain requirements regarding limits on cyclic
operation.
The pipe manufacturer should be consulted to assist in defining appropriate precautions
and measures that may alleviate or minimize this concern.
Recommendation:
The installation and regular monitoring of pulsation dampeners is recommended to
protect pipelines from excessive pulsation pressures downstream of pumps—in
particular downstream of positive displacement pumps. Some pipe manufacturers also
specify a minimum length of steel pipe between the pump discharge and the start of the
reinforced composite pipe. Other measures for reducing the severity of surge pressures
at the design stage, include slow-acting valves and variable frequency drive (VFD)
controlled pumps.
The pressure test requirements following field installation must also be considered
when determining a suitable pipe product and MPR. Minimum test pressure can be
calculated using the following equation—as specified in CSA Z662-2019:
Minimum Test Pressure = Design Pressure x 1.25 (Equation 2)
Generally, reinforced composite pipelines should not be pressure tested for the field
proof test at a pressure above the manufacturer’s published specification and
recommendations (it may exceed the specified MPR of the pipe), unless approved in
writing by the pipe manufacturer. The designer should also ensure that the
manufacturer’s flanges are rated for the selected test pressure. The pipeline designer
should review this aspect with the pipe manufacturer and consider this when selecting a
suitable reinforced composite pipe product.

4.5 Design Temperature

Design temperature is based on the pipeline service fluid conditions and any upset
conditions that may occur. Once determined, the temperature can be compared to the
various pipeline temperature ratings published by pipe manufacturers. Note that

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reinforced composite pipes—including stick and spoolable pipes—have varied maximum
service temperature ratings which should be determined on a product basis. The
designer should also consider that service fluid temperatures in an oilfield may
significantly increase over time due to changes such as increasing water cuts or the
introduction of high-volume downhole pumping.
The effect of elevated temperature on the MPR should also be determined during the
design stage. In some cases, the MPR may have been qualified by the manufacturer at
the rated temperature or at a lower temperature (e.g., 60oC or 23oC) and a higher rated
temperature determined by the manufacturer by extrapolation of the lower
temperature testing results.
Some manufacturers have published de-rated MPR values for the maximum
temperature rating, for instances where the maximum temperature rating exceeds the
pipe’s qualification testing temperature. For example, if a pipe manufacturer publishes a
pipe MPR at 60oC they may still allow applications up to a higher temperature, such as
90oC at reduced MPRs. Therefore, the MPR at the maximum temperature should be
determined and used for the pipeline design.
Spoolable pipe products utilize a thermoplastic inner liner. The most common liner
material used is high density polyethylene (HDPE). For initial products available, the
most common HDPE grade utilized was PE 3608 inner liner material, however PE 4710 is
currently used widely.
For their standard design pipes, spoolable pipe manufacturers published upper
temperature ratings of 60oC. In some products, where alternate liner materials are
used—such as bi-modal HDPE or cross-linked polyethylene (PEX)—slightly higher
temperature ratings up to 82oC may be specified by the manufacturer. Alternate new
liner materials are under constant development so end users should check for most
recent upper temperature ratings with manufacturers. The pipe’s maximum
temperature rating and the proposed pipeline’s maximum operating temperature
should be reviewed and verified with the pipe manufacturer.
For stick pipes, various upper temperature ratings (from 65oC to 100oC) are available
that are based on the type of epoxy resin that is utilized and qualified for the pipe
manufacturing. This aspect is covered in more detail in Section 5.
Recommendation:
Verify the maximum pipe temperature rating for the specific pipeline service fluid
involved. The manufacturer’s maximum pipe temperature ratings may be service fluid
based. Do not assume that the manufacturer’s specified maximum temperature rating is
suitable for all service fluids.
The minimum allowable operating temperature for spoolable composite pipes with
HDPE liners is typically -200C but for some spoolable composite pipe products is 0oC and
should be verified by the designer. This is an essential design criterion for applications
where winter construction or low temperature services, as well as start-up where Joule-

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 Thomson cooling effects due to gas expansion can significantly lower the service
temperature of spoolable pipe risers.

4.5.1 Thermal End Load

The development of forces due to thermal expansion of stick composite pipe is less than
the forces developed by steel pipe of the same diameter. This is due to the relatively
low axial modulus of elasticity compared to steel pipe. See Table 4-1.
A standard equation used for the calculation of thermal end-load of pipe is given by:
P = α E A ΔT (Equation 3)
Where:
P= End load
α=Coefficient of thermal expansion
E= Modulus of elasticity
A= Cross sectional area
ΔT= temperature change
As Equation 3 demonstrates, because stick composite pipe carries a lower value of the
axial modulus of elasticity (e.g. 1:15) compared to steel, the end loads developed due to
temperature changes will also be much lower than loads developed by steel pipe of the
same diameter.

4.6 Fluid Velocity

Reinforced composite pipes are used in normal fluid flow pipelines with liquid velocities
up to 8 m/s. Velocity restrictions are usually based on the potential for pipe and fittings
wear due to very high flow rates. The combined effect of fluid flow rate and the
concentration and type of solids loading should also be considered as each case will be
unique.
Surge flow for two-phase or single-phase pipelines, that may occur during normal
operation or at start/stop conditions should also be assessed as damaging loads may be
generated by pressure surges. In some cases, operators may have to reduce operating
velocity, especially for some two-phase services in order to prevent pipe damage.
Specialty pipes may be available that employ special inner resin surfaces or liners of
polyurethane and other similar materials, which are designed to provide increased
abrasion resistance.

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4.7 Pipeline Risers

4.7.1 Risers for Reinforced Composite Pipelines- General

CSA Z662-19 has specific requirements for reinforced composite pipelines risers. Steel
risers must be supported so that no damaging load is applied to the reinforced
composite pipe.
Where the transition to steel piping is above ground, CSA Z662-19, Clause 13.1 specifies
that the design of the pipeline shall provide:
• Adequate pipe support,

• Anchoring methods in accordance with the manufacturer’s installation

recommendations,

• Measures to prevent damage to the reinforced composite pipe and the transition
connection,

• Management of stresses on piping due to thermal expansion and soil

settling/compaction,

• Protection from weather, especially solar heating and ultraviolet damage,

• Protection from unintended contact and mechanical damage, and

• Measures to prevent piping damage from fire such as from grass or brush fire
encroachment.

Where the transition to steel piping is below ground, CSA Z662-19 Clause 13.1 specifies
that the design shall provide
• Suitable pipe support and anchoring in accordance with the manufacturer’s
installation recommendations,

• Pipeline backfill in accordance with the manufacturer’s recommendations, and

• Management of stresses due to thermal expansion and soil settling/compaction.

In addition CSA Z662-19, Clause 13.1.2.16 specifies that for steel risers and below-
ground components such as metallic connectors or steel pipe risers that are connected
to reinforced composite pipe, the requirements for internal and external corrosion
control of the steel pipeline portions shall be determined in accordance with CSA Z662-
19, Clause 9, except as follows:
• For corrosion control of risers or below ground components, where either solid
corrosion resistant alloys (CRA) or corrosion resistant metallic coatings are used,
additional external corrosion protection such as cathodic protection is not required,
provided that an engineering assessment indicates adequate corrosion resistance

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 for the intended life of the pipeline. The engineering assessment shall include
consideration of the

o expected life of the alloy or coating,

o potential for external corrosion at coating holidays,

o effect on the life of the coating as a result of such holidays, and

o where the result of the engineering assessment is to retain the

requirements for additional external corrosion protection as specified in
Clause 9, such protection measures shall be specified in the design.

• Cathodic protection installed on metallic risers shall be monitored while CP

monitoring installed on fully buried inline components is optional.

4.7.2 Risers for Stick Composite Pipe

Pipeline risers for stick composite pipelines should be carefully designed and installed,
as they may experience significantly higher stress accumulations at the end points of the
pipeline. Examples include stress buildup due to operating temperature cycles, pipe
operating service pressure and cycles, service fluid hammer surges, pigging, and soil
settling around and below the riser pipe area.
For stick composite pipelines, different riser designs have been implemented such as
the use of
• Steel pipe risers that transition to the stick composite pipe in the pipeline trench,
usually at the bottom of the riser, and

• Stick composite pipe riser that is transitioned to steel piping just above ground level,
usually with a flanged connection.

Rigid fiberglass installations also often require the installation of thrust blocks (anchors)
at elbows to control stresses and prevent elbow damage.
The differences in material weight and settlement need to be considered where stick
composite pipe is transitioned to a steel flange below ground. This is important, as the
composite flange and/or adjacent composite pipe could be damaged and possibly fail by
differential settling between the two connected materials or if the riser piping is fixed in
position.
As stated previously, CSA Z662-19, metallic risers connected below ground to reinforced
composite pipelines should be supported so no damaging load is induced on the
reinforced composite pipe. This includes situations where unstable soils exist, as the
reinforced composite pipeline cannot be expected to provide support to a heavy steel
riser pipe section and steel flange.

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Recommendation:
Internally coated risers can have limited life expectancy in corrosive services and should
be included in pipeline inspection and integrity management programs.
CP effectiveness for metallic pipe risers should also be monitored.
Where the riser is constructed from stick composite piping and connected above ground
to a steel piping system, extra measures should be taken to lower risks of damage and
possible failure. These measures should be considered by the pipeline designer and
discussed with both the pipe manufacturer and the installation contractor.
Such measures to consider include but are not limited to the following examples:
• For stick composite pipe risers, heavier wall pipe for the riser section should be
used. For example, if the pipeline is constructed with a 7000 kPa rated pipe product,
consider constructing the riser pipe sections with higher wall thickness pipe and
fittings. For short riser pipe sections, the incremental cost of the higher rated
composite pipe and fittings should be minimal. The use of heavier wall pipe will
result in a smaller internal diameter. If the pipeline is to be pigged, the use of a
suitable pig that can pass through the different bore diameters without damaging
the pipe is required.

• When using elbow fittings, 90-degree elbows are generally used at risers. In some
cases, 45-degree elbows may be installed. The use of elbows is not recommended if
the lines are designed to be pigged. Elbows may further limit future above-ground
remote camera inspection surveys or the ability to insert coiled tubing units in the
event of blockages.

• Allowable restraints and supports for the bottom transition fitting and riser pipe are
often specified by the pipe manufacturer (e.g. the use of sand-bagging or select fill
such as sand).

• Pipeline riser areas are often large over-excavated areas, usually much more so than
for the pipeline trench. Re-establishing acceptable soil compaction and stability,
both in the pipeline trench leading up to the riser and in the area immediately
surrounding the riser, is therefore recommended. This may be accomplished by
means such as select soil placement and compaction.

• Placement of steel support beam structures below the stick composite carrier pipe
through areas of unstable soil such at wellsites or plant facilities.

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 Figure 4-1 Pipeline Riser showing use of Sand Bagging for Support and
Thrust Blocking. Composite Riser Extends above Grade to Flange Transition
to Steel Piping (Photo used courtesy of Western Fiberglass Pipe Sales Ltd)

4.7.3 Spoolable Composite Pipeline Risers

For spoolable pipeline risers, either steel risers or bringing the composite pipe above
ground and transitioning to steel pipe have been used. Many of the same concerns
expressed in 4.7.2 for stick composite pipe risers also apply to the spoolable pipe risers.
Spoolable composite pipes by nature are designed to bend and be flexible and are
expected to be somewhat more tolerant of typical stresses developed at pipeline risers
than stick composite pipe. Despite this, the riser design for spoolable pipe still requires
due consideration of soil stability and pipe support as stated above for stick pipe.
Note that each spoolable pipe product will respond differently to stresses, such as
bending, depending on the type and amount of reinforcement. The manufacturer
should be consulted to determine allowed maximum pipe deflections.
Some spoolable pipe manufacturers recommend and supply a steel support chute
structure to be installed for spoolable pipe risers. This structure is designed to cradle
and support the pipe through the riser section. If available, this option should be
considered to help restrain and support the spoolable riser pipe section. In particular
when dealing with ground vibration effects from oilfield pumps that could lead to soil
settling after compaction/backfill (regardless of whether cyclic service effects have been
taken into account), steel support structures are recommended.

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The use of a steel support introduces a more rigid structure for the riser section.
Therefore, where the riser exits the support and transitions from the rigid steel support
to soil, it must be fully supported to prevent excessive pipe shear stress due to loading
from soil settlement.
Caution should be used for placing and tightening U bolts or clamps on chutes used to
hold pipe against the chute, as it can lead to damage to the reinforcement layer if the
hold-down bolts are tightened excessively.
In some cases, steel pipe risers are used where severe water hammer or pressure cycle
fluctuations are expected. In these situations, the pipe manufacturer’s technical staff
should always be consulted to review the design including the transition connection to
the spoolable pipe. Consideration of the extra support required for a heavier steel pipe
riser and flange are required to ensure no damaging stress is placed upon the spoolable
pipe.
CSA Z662-2019 requires CP installation for steel risers including monitoring of the CP
system over life.
Note: Soil settlement or operating conditions can cause differential movement between
fixed riser piping and the composite pipeline. This movement may place excessive
bending stress that is concentrated at the transition fitting and cause damage and can
lead to failure.

4.7.4 Spoolable Composite Pipeline Couplers

Metallic couplers are used for transitioning spoolable pipe to steel piping or for inter-
connection of spoolable pipe sections. The couplers are not a standard industry design,
as each pipe manufacturer designs and supplies their own couplers. Manufacturers will
often install the couplers, or in some cases train and certify other companies to install
their couplers. The couplers are not interchangeable from one type of spoolable pipe to
another, however flange designs are available from most manufacturers that may allow
connecting two different spoolable composite pipes. When flanged designs are used,
consideration should be given to the issues associated with buried flange installation,
such as bolt tensioning, preservation in conditions affected by thermal expansion and
soil settlement loads.
For the design of spoolable pipelines, the coupler material must be considered in terms
of both internal and external corrosion resistance. This is typically accomplished through
discussion with the pipe/coupler manufacturer. Options available typically include use
of plastic coatings, corrosion resistant alloy (CRA) or metallic coatings such as electroless
nickel coating (ENC).
Additional information on coupler material selection and associated CSA Z662-19
corrosion mitigation requirements are presented in sections 4.7.1 and 5.2.

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 Figure 4-2 Spoolable Pipe Metallic Coupler (Wooden Beam to be removed for Installation)
(Photograph courtesy of FlexSteel Pipeline Technologies Ltd.)

4.8 Fluid Hammer

Fluid hammer in a piping system is caused by sudden starts or stops of flow. This can
create high-pressure surges that can damage piping—including steel piping. This should
be considered when designing pipe systems especially where stick composite pipelines
are involved. Fluid hammer has been known to cause pipeline failures that often
manifest at changes of direction within the pipe, such as at elbow or tee fittings used for
lateral pipe connections or risers.
Some of the common causes of high surge conditions are fast-acting valves or quick
pump start-up. In these cases, the use of VFD or slower acting valves—such as piston
check valves or slow operating control valve actuators—is recommended to minimize
pressure surge conditions. Within their design manuals, pipe manufacturers publish
guidelines and fluid hammer constants to enable users to consider and calculate the
effects of fluid hammer. The surge pressure conditions caused by two-phase flow or
other cyclic pressure operations should also be determined and included within the
pipeline’s design pressure.

4.9 Vacuum
The design must also consider potential for vacuum conditions that can lead to pipe
damage, especially for some spoolable pipe products where the un-bonded inner liner
layer may separate from the reinforcement and collapse under vacuum. This may be
mitigated by having vacuum controls on the pipeline. The resistance to vacuum collapse
is based on several factors including the pipe operating temperature and pipe diameter
and should be reviewed with the product manufacturer.

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5 Material Selection

5.1 Reinforced Composite Pipe Materials

5.1.1 Stick Composite Pipe Products

The materials used for stick composite pipe are a combination of a reinforcement
composed of glass fibre and a matrix binder composed of thermosetting resin—most
often an epoxy resin for oilfield pipe. The end user is not normally involved with the
specification of these raw materials but should be aware of some of the general
properties affected by the raw materials.
E-Glass (a general-purpose glass fibre) is generally used for reinforcement glass;
however, in some cases C-Glass is used to increase chemical resistance. Glass fibres are
considered strong materials, as they have a typical tensile strength value of
approximately 3,400 MPa at 23oC and have a modulus of elasticity of approximately 70
GPa.
As stated in Section 4.0, the resin matrix used to produce stick pipe will vary from each
pipe manufacturer. In general, most stick composite oilfield pipe is manufactured from
epoxy-based resins. However, using different types of epoxy curing agents will affect the
pipe’s chemical resistance and temperature ratings. The temperature ratings for generic
common epoxy resins are as follows, manufacturers specific temperature ratings should
always be consulted:
• Anhydride cured epoxy: 65oC;

• Aliphatic amine cured epoxy: 93oC;

• Aromatic amine cured epoxy: 100oC,

Recommendation:
Although pipe manufacturers publish the chemical resistance of their products within
their product literature, project-specific discussion should be held with manufacturers,
as the maximum temperature ratings published may not apply to all fluid environments.
In some cases, specific testing may be necessary to qualify stick pipe products before
selection is made.

5.1.2 Spoolable Pipe Products

Spoolable pipe products are characterized by having a thermoplastic inner liner pipe
layer. The most common liner material used currently is HDPE Grade PE 4710.
Historically HDPE Grade PE 3608 liner was used. Both of these liner materials have the
same general chemical resistance and may be affected by the absorption of liquid
hydrocarbons. PE 4710 has increased mechanical properties that are discussed below,
and temperature resistance compared to standard PE 3608.

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Generally, the physical absorption of hydrocarbons is known to affect HDPE mechanical
properties such as tensile strength and modulus of elasticity. Water, on the other hand,
is known to have little effect on the properties of HDPE.
HDPE liners can also allow a small amount of gas permeation through the pipe wall. In
some cases, spoolable pipe products include a small vent port in the metallic couplers to
allow gases that have permeated through the inner liner to migrate to the vent port.
Each vent port can be equipped with a spring-type vent valve preset to a certain low
pressure. The annular venting system gives the end user the capability of capturing the
permeated gases, resulting in zero emissions.
Where elevated service temperatures are required, the use of the alternate PE-RT, PEX
or polyamide (PA) inner liner materials may be considered.
HDPE Grade 4710 liners are stated to have slightly improved mechanical property
retention, stress crack resistance, crack arrest properties and higher temperatures
mechanical properties, compared to standard HDPE Grade 3608.
The reinforcement structure applied over the inner liner generally includes windings of
glass fibre strands—similar to stick composite pipe. Other reinforcement materials such
as aramid fibres, carbon fibre, steel wire or steel strips may be used for some products.
These reinforcements are added and built up in layers that are designed to provide the
required axial and hoop strength properties.
SCP: spoolable pipe products referred to as spoolable composite pipes (SCP) use glass
fibers encased in a thermosetting epoxy resin matrix with the reinforcement structure
directly bonded to the inner liner with an adhesive.
RTP: spoolable products referred to as reinforced thermoplastic pipe (RTP) use dry
reinforcement such as glass fibre strands, wound over the liner with no epoxy resin
matrix—in these cases the reinforced dry structural layers are not bonded to the inner
liner. Currently, there are spoolable pipe products that use carbon steel strips,
galvanized steel wire cords or fiber tape windings over the inner liner.
Recommendation:
The end users should understand that the type of reinforcement and design strongly
affects the spoolable composite pipe mechanical properties. Properties such as tensile
strength, impact resistance and cyclic pressure resistance will vary significantly between
different pipe products. Therefore, different SCP and RTP composite pipe products
cannot all be designed and installed in the same manner.
Whatever the reinforcement method employed for spoolable pipes, the temperature
and chemical resistances are strongly linked to those of the inner liner material, since
the strength of either glass fibre or steel strip reinforcements should not be significantly
affected by normal pipeline operating temperatures. As well, the pipeline service fluid
must remain isolated by the inner liner and not directly contact the annulus
reinforcement layers other than through gas permeation.

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 The possible effects of permeated gases (such as CO2, H2S and water vapour) on the
metallic or glass fibre reinforcement layer structure materials and the spoolable pipe’s
long-term integrity should also be considered and discussed with the pipe
manufacturer. Permeation of strong solvents such as Xylene may also occur and affect
the bonding adhesive in the case of SCP products. Aside from steel reinforcment
corrosion concerns, the presence of water in the annulus may also affect the strength
and integrity of dry fiberglass reinforcement windings used for certain spoolable pipe
products.
The chemical resistance of inner liner material within spoolable pipe is an important
consideration. For example, adverse effects could be caused by the use of strong
hydrocarbon solvents in pipes with a standard HDPE liner and should therefore be
avoided. In general, the effects of water on the HDPE liner—within the pipe’s
temperature rating limit— should be minimal. As stated above, water presence in the
annular space may affect the strength of dry glass reinforcement windings of some
spoolable pipe products. Testing may be necessary to qualify spoolable pipe products
before final selection is made.

5.2 Material Selection for Metallic Couplers (Spoolable Pipe)

Normally, pipe manufacturers supply metallic couplers for their pipe products, which
are often made in-house by the manufacturer or outsourced. The standard coupler
material is plain carbon steel. End users should consider and determine whether
standard carbon steel couplers will provide adequate service life in the service fluid
before specifying an appropriate material.
Available material options include organic protective coatings such as thin
fluoropolymers or polytetrafluoroethylene (PTFE). Some manufacturers offer their steel
couplers with an electroless nickel coating (ENC) while in some cases the entire coupler
can be made from corrosion resistant alloy (CRA) such as stainless steel, duplex, or
nickel alloys. Where highly corrosive service fluids such as oilfield brines are present, the
use of some thin metallic or plastic protective coatings may not provide adequate
corrosion protection therefore solid CRA couplers may need to be considered.
The selection of coupler material must be done with consideration of the service
conditions. The use of bimetallic materials such as CRA mandrels welded to carbon steel
sleeves or ENC steel in water or brine service, must be carefully evaluated to avoid
dissimilar metal corrosion. The use of non-metallic (plastic) coatings must take into
account operating conditions such as produced sand or presence of chemicals that may
affect the coating. Similar to metallic riser design, when plastic coatings are used in
piggable lines, the selection of the correct pigging procedures must be specified. This
involves selection of the right pig geometry and durometer hardness that would
perform well and at the same time maintain the integrity of the coating.
External corrosion protection of the couplers is usually achieved through the use of
external coatings, ranging from polyethylene sleeves or tape to liquid epoxies and

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 viscoelastic mastics. It is recommended that external coatings are used on all coupler
materials, even those that are not normally affected by external corrosion.
Field-applied pipeline coatings should be applied in accordance with CSA Z245.30-2211.
For additional protection, spot cathodic protection can be achieved through the use of
magnesium or zinc sacrificial anodes, specially designed and sized based on soil
conditions and design life, to offer the required protection to the coupler. Monitoring of
the sacrificial anode output and life can be done using test wires brought above ground,
but if not monitored the anode should be designed to last for the life of the pipeline or
to a planned replacement life. The use of CP test stations should take into account
practical issues such as accessibility and protection against accidental damage.
Section 4.7.4 gives additional information on corrosion mitigation requirements
specified by CSA Z662-19 for metallic couplers.

5.3 Materials for Risers

5.3.1 Reinforced Composite Pipe Risers

As discussed in Section 4.0, various material options are available for pipeline risers. It is
generally recommended that composite pipe be extended to just above grade before
transitioning to metallic pipe, as this provides a more corrosion-resistant material than
carbon steel pipe risers. Spoolable pipe manufacturers can provide a structural steel
support structure for the underground riser section.
When using a composite riser design for stick composite pipelines, it is recommended to
construct the riser section from a stronger composite pipe material than is used for the
pipeline itself. Transitioning back to the standard composite pipe in the pipeline trench
should follow. Manufacturers can normally provide prefabricated heavier walled riser
sections.
In some cases, steel supports are placed below stick pipe risers and pipe that extends
away from well sites to more stable soil conditions that may exist at the edge of the
wellsite or other field facility leases.
The use of composite riser materials must also take into account any material
limitations associated with cold temperature effects such as fast crack propagation.
Joule-Thomson cooling effects at start-up are common in rich gas applications or those
with a high content of CO2, and the pipeline risers close to the wellheads will be affected
by the sudden temperature drops.

5.3.2 Metallic Pipe Risers

Measures to prevent internal corrosion may be required should the operator wish to
install a steel pipe riser, which can be accomplished by applying internal plastic coatings.
Coating selection and application must be done by an experienced coating applicator—
preferably inside a specialty coating shop environment—as quality application is a
primary requirement. Onsite field application of internal coatings is not normally

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recommended due to poor working conditions and the need for specialized shop
equipment to properly apply internal pipe coatings.
Steel pipe risers must also be fabricated with a suitable spool geometry to allow access
for weld inspection and prepping as required. Use of specialty pipe welding processes,
such as MIG, minimizes internal weld beads and is often used for piping that is to be
internally coated. In some cases internal weld beads are removed by grinding but this
may not be possible for smaller diameters or complex piping.
External corrosion protection of the steel riser must also be considered and is usually
provided by the application of a suitable external coating system such as liquid epoxy,
heat shrink sleeves or tape wraps, and by installing a CP system as specified by CSA
Z662-19.
Field applied pipeline coatings should be applied in accordance with CSA Z245.30-22.
Both the internal and external coatings selected must be rated for the service
environment and additive chemicals, in terms of operating temperature, pressure and
chemical resistance.
Of these factors, excessive operating temperature is a major cause of coating failure.
This often occurs due to increases in production rates or water production.
CRA fittings and pipe have also been used to fabricate risers for reinforced composite
pipelines. In such cases, the alloy material and connection to the composite pipe must
be carefully selected based on their corrosion resistance to the service environment.
Alloys, such as stainless steel, have been used but some grades are known to be more
sensitive to chloride stress cracking due to the high chloride concentration present in
most oilfield waters. For more aggressive environments the use of duplex or nickel
alloys should be considered.
In some cases, specialty pre-coated weldable steel insert fittings have also been used to
fabricate a steel riser pipe section.

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6 Material Qualification

6.1 Design Stress/Pressure - Stick Pipe

CSA Z662-19 specifies that stick composite pipe be qualified and manufactured in
accordance with API 15HR requirements. The standard pressure rating should also be
determined in accordance with API 15HR12 using the 20-year long-term hydrostatic
strength (LTHS) value. The LTHS values can be determined using the test procedures of
ASTM D 2992, which are specified by API 15HR.
Each pipe manufacturer performs the ASTM D 299213 testing to determine pipe failure
pressures/stress at various time intervals. Testing procedures tend to be lengthy as
failure points of up to 10,000 hours are required for the qualification. Typically, testing is
performed using 65oC water; however, some manufacturers perform testing at other
temperatures in addition to 65oC. For tests lasting over 6,000 hours, the pipe test
sample must contain a prime connection.
For qualification of fittings, similar pressure testing of each type of fitting is performed,
with test intervals from 10 to 2,000 hours minimum. The regression is plotted the same
as pipe and the 20 year LTHS value is determined. API 15HR requires that the fitting 20-
year LTHS value exceeds the value of the same pressure class pipe.
To calculate design stress values for pipe and prime connections, pipe manufacturers
plot the failure stresses versus time on a semi-logarithmic graph to generate the stress
regression analysis. From there, the failure stress graph slope is extrapolated beyond
the 10,000-hour data point out to 20 years (175,200 hours). The predicted stress at 20
years is then determined by this extrapolation, which provides the hoop stress or LTHS
used to determine the pressure rating. API 15HR also specifies a 0.67 design factor be
applied for calculation of the manufacturer pressure rating (MPR). Design stress values
can be found in the pipe manufacturer’s design manuals.
To calculate design stress values for fittings, pipe manufacturers plot the failure stresses
versus time on a semi-logarithmic graph to generate the stress regression analysis. The
failure stress graph slope is extrapolated beyond the 10,000-hour data point out to 20
years (175,200 hours). The predicted stress at 20 years is then determined by this
extrapolation, which provides the hoop stress or LTHS used to determine the pressure
rating. API 15HR also specifies a 0.67 design factor be applied for calculation of the
manufacturer pressure rating (MPR). Design stress values can be found in the pipe
manufacturer’s design manuals.
Remember that the design stress used to determine the pipe pressure rating is pipe
hoop stress and does not consider other shear and axial stresses that may be present
due to soil loading and settlement and thermal expansion stresses. In part, these are
offset by the design factors in API 15HR and service fluid design factors specified in CSA
Z662-19.

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6.2 Design Stress/Pressure- Spoolable Pipe
CSA Z662-19 specifies that glass fibre reinforced spoolable pipe be qualified and
manufactured to API 15S while steel strip reinforced spoolable pipe can be qualified and
manufactured to meet API 15S or API 17J14. For spoolable composite pipes (SCP) and
reinforced thermoplastic pipes (RTP)—with the exception of steel reinforced flexible
pipe—the MPR is based on the LTHP testing of pipe samples in accordance with the
industry standard test method, ASTM D 2292, which is the same test method used for
stick pipe. Once the testing is completed, the LTHP is calculated in accordance with
ASTM D 2992, which involves extrapolation of the test data to determine the LTHP at 20
years (175,200 hours).
For steel strip or wire reinforced spoolable pipe, CSA Z662-19 currently allows that
either API 17J or API 15S be used for qualification and manufacturing.
The pressure rating methodology used in API 17J is based differently than procedures
specified in either API 15HR or API 15S in that an analytical approach using analysis of
each pipe layer strength is applied.
For steel strip or wire reinforced spoolable pipe qualification, API 15S utilizes a minimum
burst pressure testing procedure to determine MPR.
Manufacturers are also required to qualify the metallic end fittings and couplers for
their pipe system in accordance with API 15S specified qualification testing.
Note: API 15S was revised and published in March 2016 and in the current edition
published April 2022 to include qualification, manufacturing, and application
requirements for spoolable pipes with steel strip or wire reinforcement. CSA Z662-2019
allows either API 15S or API 17J to be used for steel strip or wire reinforced pipe
products.

6.3 Additional Qualification Tests

In some cases, additional pipe qualification may be requested for certain applications.
These should be discussed with the pipe manufacturer and follow the recommendations
of the relevant manufacturing standard.
Some examples where additional qualification may be requested include
• Effects of permeation on the pipe properties for gas or multiphase services,

• Minimum bend radius,

• Axial load capability,

• External pressure/overburden,

• Impact resistance at specified temperatures,

• Slow or rapid crack propagation resistance,

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• High-cyclic pressure services, and

• Resistance to liner collapse for rapid gas decompression applications.

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7 Installation

7.1 General
As seen on the pipeline failure data discussed in Section 2, installation damage is a
leading cause of pipeline failure. Therefore, the installation techniques for reinforced
composite pipelines, as well as consideration of the differences in the types of pipe
being used, are critical for success.

7.1.1 Spoolable Pipe Installations

When installing spoolable pipe, either plough-in or open trench construction installation
methods may be utilized. Trenchless installations are also performed by insertion of a
spoolable pipe within a conduit pipe (slip lining) and by horizontal directional drilling. To
help determine which method to use, discussions with the pipe manufacturer and
experienced local installation contractors should be held.
Where reinforced composite pipes are installed as a free standing pipe in steel conduit
pipes, the use of wireline pull-in methods are commonly used. In these cases, the
wireline unit should be equipped with an accurate weight indicator and odometer to
monitor conditions and positioning during the pulling-in operation. Data loggers can be
used to record the speed, distance and pull weight at a set frequency. Break-away
devices can be set at the maximum pull force allowed by the manufacturer.
Push/pull technology is also being used to install free standing pipe and can offer the
advantage of not applying torque to the reinforced composite pipe. This may be a factor
in long pull lengths using wireline where tensile loading of the braided wireline results in
excessive torque to the reinforced composite pipe. To prevent this, a swivel connection
device may be employed between the wireline and the pipe pulling head. Note that
push/pull technology may not be suitable all spoolable pipe products due to
compressive stresses generated, and therefore the installation method for free standing
pipe-in-pipe liners should be reviewed with the pipe manufacturer before selection.
Some of the key aspects that should be considered for a plough-in installation include
• Terrain, soil and rock conditions,

• Number of crossings required (e.g. roads, water bodies, pipelines, etc.), and

• Expected weather conditions.

In general, plough-in pipeline installations are carried out in level terrain with relatively
stable soil conditions and low rock content soils. In some cases, wintertime plough-in
construction may be possible but should be considered carefully, since the stiffness of
spoolable pipe products will increase significantly during low temperatures, thus
increasing the probability of pipe damage. Where possible, the installation of spoolable

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composite pipes during extreme cold weather conditions (< -20oC) should be avoided
due to the increased risk of pipe damage.
Recommendation:
Generally, reinforced composite pipeline installation is halted or reduced when ambient
air temperature drops below approximately -20oC. However, it is recommended that
consultation with the pipe manufacturer be conducted to determine the product’s low-
temperature limit and the required low temperature installation practices, as some
products may have a higher or lower temperature limit specified by the manufacturer.
Some pipe manufacturers have established a set of practices that allow heating and
installation of the spoolable pipe at temperatures below -20°C. Refer to Sections 2.2.1
and 7.2.2. for more information on pipe heating techniques.
See API RP 15SIH15, published by API that is a recommended practice that contains
installation and handling practices recommended for spoolable reinforced line pipe.

7.1.2 Stick Pipe Installations

When stick composite pipe is being installed, the only method is conventional open
trench construction or as an insertion free-standing liner. Where reinforced composite
pipes are installed as a free standing pipe in steel conduit pipes, wireline pull-in
methods are commonly used. In these cases, the wireline unit should be equipped with
an accurate weight indicator and odometer to monitor conditions and positioning
during the pulling-in operation. Data loggers can be used to record the speed, distance,
and pull weight at a set frequency. Break-away devices can be set at the maximum pull
force allowed by the manufacturer.
Push/pull technology is also being used to install liners and can offer the advantage of
not applying torque to the liner pipe. This may be a factor in long pull lengths using
wireline, where tensile loading of the braided wireline results in excessive torque to the
liner pipe. To prevent this, a swivel connection device may be employed between the
wireline and the pipe pulling head. Note that push/pull technology may not be suitable
all reinforced composite stick pipe products due to compressive stresses generated and
therefore the installation method for free standing pipe-in-pipe liners should be
reviewed with the pipe manufacturer before selection.
In general, stick pipe properties are not as affected by low temperatures as much as
spoolable pipe; however, the risk of damage due to frozen soil or adverse joining
conditions remains a concern.

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 Figure 7-1 Typical Spoolable Reinforced Thermoplastic Pipe (RTP) Plough-In
Installation Method
(Photograph courtesy of Flexpipe Systems)

7.2 Pipe Transportation and Handling

The transportation and handling guidelines published by pipe manufacturers should be
consulted as this aspect of pipe installation requires stringent attention.

7.2.1 Stick Pipe

Pipe transportation is usually performed using flatbed trailers that provide full-length
support to the pipe. Having any pipe hanging over the end of the trailer is not
recommended. Wooden supports (dunnage) or cradles should be positioned below the
pipe and between the stacked rows of pipe to provide support and separation. Usually,
the minimum number of rows is specified in the manufacturer’s literature and may vary
depending on the pipe diameter.
Pipe tie-downs using synthetic fabric straps should be positioned at the support points
or as approved by the pipe manufacturer. Typically, a minimum of four tie-downs are
installed. Chain tie-downs are not acceptable. During transportation, pipe ends should
be covered by thread protectors or plastic bags to prevent damage or contamination of
the connection surfaces.

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Recommendation:
Pipe used in pipeline construction projects will often be located at a nearby pipe
distributor’s storage yard, having been previously shipped there from the manufacturer.
It is recommended that a local distributor be used to transport pipe to the project site
for stringing or storage. The local pipe distributor will typically have equipped trailers
and experienced personnel dedicated for transporting and unloading reinforced
composite pipes.
Some key inspection checks that should be reviewed when transporting stick pipe
include
• Load shifting or missing supports,

• Use of specified tie down straps,

• Use of over-tightened straps and excessive bending of pipe loads,

• Signs of wear or damage to the pipe at tie-down points,

• Missing pipe-end protection at connections, and

• Examining for signs of visual damage, impact damage, and abrasion damage.

Transportation methods may vary depending on the nature of the project—such as the
use of shipping containers for international overseas projects.
Reviews of where the pipe is being unloaded and stored at the construction site should
be carried out to check for the truck unloading method, pipe storage rack configuration,
and ultraviolet protection requirements. In the event the pipe will be stored for an
extended period (several months or more) tarps should be used to protect the pipe
from ultraviolet discoloration and surface oxidation effects.
Where stick pipe has been strung along the pipeline right-of-way, the pipe may be
placed upon wooden skids, plastic pylons, or short pieces of plastic pipe to protect it
from rocks or other objects in the area.

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Figure 7-2 Typical Wooden Cradle Supports and Tie Down for Large Diameter Pipe Transport;
(Photograph courtesy of Fiber Glass Systems and Fiberglass Solutions Inc)

7.2.2 Spoolable Pipe

Many of the transportation and handling methods for spoolable pipe differ from those
for stick pipe. For instance, spoolable pipe is shipped on large shipping reels that are
carried on trailers. Further, after arriving to the construction site, the pipe reel is
unloaded and kept on the shipping reels until installation begins.
Prior to shipment, the pipe should be free of water such as from mill hydro-testing,
which may freeze in transit and form an ice plug that could crack the pipe.
API 15SIH provides a visual inspection guideline template for receiving visual inspection
of spoolable pipe that should be considered when developing inspection protocol.
Some key inspection checks that should be reviewed when transporting or receiving
spoolable pipe include
• Proper securing of the pipe reels to the trailer to prevent pipe damage,

• Pipe reel covers are in place to prevent rock impact damage caused by passing
vehicles (if specified),

• Examining for signs of visual damage, pipe kinks or impact damage,

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• Ensuring proper reel unloading methods and careful placement of pipe reels onto
the site’s ground surface that is free of rocks or other objects that could damage the
pipe, and

• Inspection of empty pipe reel surfaces for any abnormalities that may have damaged
the pipe.

• Presence of protective end caps to prevent intrusion of water or other contaminants

into the pipe annular space.

Heating of the pipe reel may be necessary prior to unreeling spoolable pipe during
winter construction—refer to Section 2.2.1 for more information. Spoolable pipe
products, unlike stick pipe, rely on a thermoplastic inner liner material—normally HDPE.
Thermoplastic materials are very sensitive to temperature and at low ambient
temperatures will become much stiffer and less ductile. The heating procedure should
be done carefully and in accordance with the manufacturer’s procedure. If the pipe reel
is heated unevenly, resulting in hot and cold areas, this can result in significant
variations in the pipes stiffness and pipe kinking damage can occur during unreeling.
Care should be taken in order not to overheat the pipe above its specified temperature
limit.

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 Figure 7-3 Spoolable Pipe Transport on Reel Trailer
(Photograph courtesy of FlexSteel Pipeline Technologies Ltd.)

7.3 Pipe Installation

Pipe manufacturers provide installation instructions that should be followed to
successfully install both stick pipe and spoolable pipes. Normally, the manufacturers can
provide a field service technician or help train and qualify the installation crew and
inspectors in the proper handling, joining, and installation techniques.
Should any suspected damage on the pipe be evident, a manufacturer’s representative
can provide pipe inspection and assessment assistance. The representative’s services
should also be utilized during installation pre-bidding meetings, installation planning
meetings, and onsite during field construction. Note that manufacturers can supply
different services, and their services should be understood to properly bid a project.

7.3.1 Pipeline Trench Preparation

In general, the pipeline trench bottom should provide continuous and stable support for
the pipe. In the event soil conditions are too soft, unstable or rocky, it may be necessary
to over-excavate the area followed by the placement of bedding materials in the trench
bottom. The depth of bedding in most situations should be a minimum of 150 mm.
Rocks that contact the pipe can lead to in-service pipe failures, due to wear against the

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pipe wall when the pipe expands or contracts due to pressure or temperature changes
in service.
Stick pipe is more rigid and should be supported by a uniform flat trench bottom to
avoid creating poorly supported spans, which could overstress the pipe once backfill soil
is placed in the trench. Spoolable pipes are more flexible by nature and can generally
tolerate and conform to a slightly more undulating trench bottom, however the trench
should have no sharp changes in elevation depth.
After being placed into the trench, additional bedding material may be required to fill
around the pipe and provide a more stable soil base and cover. In some cases, native
soil may be acceptable for bedding and initial cover but will require local assessment as
site conditions may vary.
A major percentage of reinforced composite pipe failures is caused by pipe shifting due
to excessive soil settlement. Where soils or the soil conditions are unstable, additional
measures are required to stabilize the pipeline ditch. Where the right-of-way conditions
have muskeg or high-water table conditions, geo-textile can be placed below the pipe to
minimize sinking. Geo-textile may also be put over the pipe to help stabilize the backfill
material. Some spoolable pipes will float and require ant- buoyancy measures such as
weights. Where unstable trench conditions are present, the use of steel pipe casings
with end seals may be required as geo-textile alone may not be adequate.
Aside from the pipe manufacturer’s installation manuals, industry standards such as
ASTM D3839, AWWA M45, and AWWA C95016 provide information on pipeline trench
preparation and backfilling requirements for composite pipes.
CSA Z662-19 specifies that the soil characteristics with the pipeline trench be in
accordance with ASTM D3839 and the pipe manufacturer’s installation procedure..
During cold weather periods, unfrozen clean soil or sand should be initially placed in the
trench—backfill containing frozen soil lumps should not be used. Soil lumps do not
provide stability and can cause pipe impact damage during backfilling.
Also, if any free water is present, the trench should be pumped out and inspected for
signs of poor pipe support such as the presence of voids beneath the pipe, which may
be caused by an uneven trench bottom, pipe bridging, etc. Any voids should be spot-
filled with soil.

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 Figure 7-4 Large Diameter Rigid Composite Pipe; Placement of Select Fill
Bedding.
(Photograph used courtesy of Fiber Glass Systems and Fiberglass Solutions
Inc)

7.3.2 Road and River Crossings

Road or river bored crossings are cased as specified by regulatory requirements. CSA
Z662-2019 has requirements for cased and uncased crossings or the uncased borehole
that include the steel casing design as well as support and protection for the composite
carrier pipe where it exits the casing or borehole.
For some crossings, plastic centralizers are fixed on the carrier pipe to provide abrasion
protection during pipe insertion through the steel casing. End seals should be
considered and installed to prevent water entry into the casing end. If possible, an
additional abrasion protective coating should be used on the exterior of the pipe.
When installing through horizontal directionally drilled crossings, the first metre of pipe
attached to the pulling head should be removed and thoroughly examined to check for
tensile or torque stress overload damage.

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 Recommendation:
The reinforced composite carrier pipe should be additionally supported and protected at
the exit ends of the bore hole or casing to prevent high shear stress due to soil settling
and from any sharp edges at the cut end of the steel casing. The soil at the casing exit
ends can be stabilized through means such as compaction and sandbagging to minimize
pipe settling and the development of high shear stress to the carrier pipe at the casing
exits.
It is also good installation practice to provide a suitable straight length of pipe before
and after the casing exit, and before a bend or elbow fitting is installed. Directional
changes—if located too close to the casing exit—may result in damage if the composite
pipe under operational pressure becomes pushed against the wall or the end of the
steel casing. In some cases, this has resulted in damage and service failures of
composite pipelines.

7.4 Thrust Blocks and Anchors

The requirements for thrust blocks and anchors should be carefully determined for
composite pipe projects. More flexible spoolable reinforced pipes are generally less
likely to require thrust blocks than more rigid stick pipe. However, in all cases the end
user should review this with the pipe manufacturer to help determine whether they are
required.
Generally, higher pressure pipelines have an increased requirement for thrust blocks
than lower pressure pipelines, which require less or possibly no thrust blocks. Thrust
blocks can take many different shapes including concrete blocks and sandbagging (a
widely used alternate to concrete blocks) and may be required for both elbow and tee
fittings as recommended by the pipe manufacturer.
Note:
Clamping pipes to steel piles at the bottom of the pipeline trench may not be
an acceptable approach for anchoring non-metallic pipelines. Consulting the
pipe manufacturer before employing this method is advised.
Regardless of the design of thrust blocks, the user should be aware that the improper
use of thrust blocks can lead to early pipe failure due to excessive point-loads or shear
stress development. This is often due to pipe and soil settling and stress or strain caused
by the operating temperature and pressure. For most oilfield pipelines, sandbagging at
the risers may provide adequate support and thrust restraint. This is especially true
immediately after construction when freshly placed soils may have low compaction
around risers and the pipeline.

7.5 Pipe-in-Pipe
Installing reinforced composite pipe as a free-standing, smaller diameter pipeline inside
an existing steel conduit pipeline is commonly performed using both stick and spoolable

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composite pipes. Note that pull lengths can vary based on pipe diameter, terrain and
the product being installed.
It is highly recommended to have the pulling installation company involved early in the
planning phase.
Several risks that should be assessed include the condition of the steel conduit pipe, the
potential for the reinforced composite pipe damage due to surface roughness, and the
existence of excessive internal weld penetrations or grapes.
Where installed inside possibly rough surface conduit pipes—such as cement-lined steel
pipe—the risk of abrasion damage may be increased especially if the pipeline is in high-
pulsating or vibrating service. Thorough pigging of any debris that may exist in the
conduit pipe before pulling in the composite pipeline is also very important and key to
lowering the risk of damage.
The diameter difference between the composite pipe’s outside diameter and the
conduit pipe’s inside diameter should be reviewed to ensure adequate clearance exists.
The reduced diameter at weld penetrations, as well as the thermal expansion of the
composite pipeline, should also be considered before selecting the free standing pipe
diameter. The OD of the reinforced composite pipe connection, if being pulled through,
must also be considered.
When installing spoolable composite pipe as a free-standing pipe, generally somewhat
less clearances are possible than those required for stick pipe due to reduced OD of the
connections. However, for all pipe-in-pipe installations proper risk assessment and a
contingency plan should be done on a case-by-case basis, as each case is unique. A
thorough discussion with the pipe manufacturer and the installation company is
advised.
Typically, the pipe-in-pipe installation involves preparing the conduit pipe by pigging to
ensure it is free of significant deposits and liquids. Leaving free water in the conduit pipe
may lead to freezing off the annulus behind the composite pipe after installation that
may cause damage. Running a pig with a minimum diameter sizing plate is highly
recommended. After initial pigging and cleaning, a wireline cable should be pulled inside
the conduit pipe by a pig. An additional check is to then pull a short section of the
composite pipe to allow for inspection of any potential damage such as significant
scratches or gouges. Elbow fittings and bends that are below the minimum allowed
bend radius of the reinforced composite pipe should also be removed prior to
installation. Additional conduit pipe preparations may also be required to locate and
remove any sections of damaged (e.g. kinked) conduit pipe, or welds that may be
damaging to the composite pipe. Tracer wire will need to be installed at all mid-point
bell-holes where the section of steel was removed.
Once the composite pipe has been pulled inside the steel conduit pipe, observations of
the composite pipe exiting the far end of the conduit pipe will indicate whether any
damage has occurred. Installing seals at the steel conduit pipe ends to prevent the entry

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 of water into the annulus space—which could freeze and damage the composite pipe—
is useful for preventing damage.
Where the reinforced composite pipe exits the conduit pipe, it should be well supported
by placement of stable soil with compaction or sandbagging to prevent excessive
settlement and shear stress development at the edge of the fixed steel conduit pipe. In
some cases, at composite pipe inter-connection points, a steel outer casing is provided
after the liner has been interconnected. Placement of a protective rubber sleeve or seal
under the composite pipe at the end of the casing may also be considered. Use of GPS
to locate these points for future maintenance or inspection is recommended.
It is recommended that cathodic protection be maintained on the steel conduit pipe and
it may be necessary to provide a jumper wire across sections where the steel pipe is
removed for the pipe-in-pipe installation.

Figure 7-5 Spoolable Composite Pipe (SCP) - Unreeling Pipe for Placement in Pipeline Trench.
(Photo used courtesy of Fiberspar LinePipe Canada Ltd)

7.6 Metallic Tracer Wire

Unless demonstrated that the pipe is electrically conductive, it is a requirement of CSA
Z662-19 for reinforced composite pipelines to install a corrosion resistant tracer wire
(minimum 12-gauge standard single strand coated copper wire) adjacent to the pipe
within the trench, to allow for detection by pipeline location equipment. This step is
especially critical to ensure the accuracy of future excavations that may be required for

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 maintenance, foreign pipeline crossings, and adjacent pipeline construction. For more
critical crossings such as HDD installations, dual tracer wires are installed by some
operators.
Following construction, the tracer wire ends should be brought to the surface in a
conduit and marked and secured to provide for easy access and use in the future.
Note:
Tracer wire is not required where steel strip or wire reinforced spoolable pipe
is installed electrically continuous from one pipeline spool to the next, as the
pipe’s steel reinforcement will provide the required response to line location
instruments.
Pipeline locator tools can be connected to either the steel pipe or the steel reinforced
spoolable pipe. Where a non-conductive pipe—such as stick composite—is used for the
riser, a tracer wire should be installed along the riser section and connected to the steel
strip reinforced spoolable pipe.
In addition to tracer wires, the use of GPS locator records for spoolable pipe couplers is
highly recommended.

8 Pipe Joining

8.1 Stick Composite Pipe

It is strongly recommended that the qualifications and experience of joining personnel
specifically related to non-metallic materials be considered in the selection of the
installation contractor. At the front end of projects, training and qualification of
personnel should be carried out by the pipe manufacturer, well before production
joining for the pipeline kicks off. It is also very important that Inspectors are fully aware
of the joining procedure and inspection and test plan requirements that pertain to the
specific products and conditions.
Note:
Each pipe product carries unique joining requirements, therefore the previous
experience personnel may have with one product may not mean they are
necessarily qualified for joining all pipe products. Unique requirements for
joining fittings to pipes and risers should be covered in pre-job training and
qualification.
CSA Z662-19 requires that reinforced composite pipes are joined using one of the
following:
• A threaded connection as specified in API 15HR. For gas service, threaded
connections shall employ a thread type that has been previously tested and found
suitable for gas service

• A mechanical threaded connection, using an elastomeric seal

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• Piping connections, using a flange joint that is compatible with the pipe

• For continuous length (spoolable) reinforced composite pipe, a field-applied splice

or fitting that is compatible with the pipe and approved by the pipe manufacturer,
or

• For other than gas service, an adhesive bonded joint, using an adhesive that is
compatible with the pipe and is suitable for the conditions to which it is intended to
be subjected during installation and service.

CSA Z662-19, section 13.1.6 also has several requirements for the training and
qualification of composite pipe joining personnel. These requirements are summarized
by following points:
• The end user company must ensure the joining personnel are qualified in the joining
procedure by the pipe manufacturer or their representative.

• The qualification process involves both training and assessments by the pipe
manufacturer.

• Assessment includes both witnessing test joint assembly and visual assessments of
completed production joints, in some cases assessment may be completed as a
formal quality audit.

• Joiner upon completion receives a certificate of qualification from the manufacturer

that gives the joining techniques trained and qualified for, along with an unique
identifier number for traceability.

• Pipeline installers (contractors) must maintain documented evidence for pipe joiners
within their organization.

• Joining personnel shall maintain and provide records of their training, qualification
and work experiences in industry. Records are to include the number of joints
completed, pipe sizes, pressure ratings, fittings experience, project descriptions,
pipeline lengths and tie-in joints.

For example, a recommended torque value for 2.5” stick fiberglass API 8 round pipe
threads can be in the range of 150-200 ft-lbs; whereas for the equivalent size steel pipe
also with API 8 round threads, a typical value is 1200-1300 ft-lbs.
On stick pipe, one of the most common joint failure mechanisms is due to over-
tightening (over-torquing) of the threads, which leads to cracking or other damage to
threads. Cracking usually manifests within the pipe pin threads (male threads). If over-
tightened, the tapered pin is excessively deformed within the stronger pipe coupler end,
and cracks. Also note that under-tightening of threaded joints is also a problem due to
lack of thread interference and sealing force at the joint.

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Extreme care must also be taken to not cross-thread joints during makeup assembly,
which can lead to thread damage and failure.
Recommendations:
1. The assembly of threaded pipe and fitting joints requires strict adherence to
make-up procedures including the use of manufacturer-approved tools only. For
threaded joints, the approved wrenches are normally designed with handles of reduced
length to prevent exceeding the maximum torque values.
2. Thread cracks due to over-tightening can occur, are usually not visible, and may
or may not fail during pressure testing post-construction, therefore they may eventually
lead to in service failure.
3. Under-tightening of joints is also problematic and can result in thread leaks due
to lack of thread engagement and sealing interference force.
4. Do not over tighten threads past recommended make-up position through use of
improper elongated wrench handles or so-called snipes.
Larger diameter stick pipe connections may require an adhesive bonded connection.
Again, project personnel training and qualification by the pipe manufacturer’s
representative are necessary. The bonder qualification methodology specified in ASME
B31.3, Chapter VII17 has been utilized for some large-diameter composite pipeline
projects with good success.
The minimum joining procedure for adhesive bonded pipe joints should include
• Adhesive type and mixing, and handling requirements,

• Cleaning and preparation of the connection surfaces for joining,

• Field tapering of pipe-ends if required (pipe joints are factory tapered),

• Application of adhesive,

• Pipe stabbing, using a hydraulic come-along for joint make-up and preventing joint
backing out after stabbing (prior to the adhesive curing period),

• Adhesive curing requirements and the use of auxiliary heating blankets,

• Inspection and acceptability criteria, and

• Provision of suitable protection or shelters for pipe joining for adverse weather
conditions such as rain or low temperatures.

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 Figure 8-1 Provision of Shelters for Joining Composite Pipe;
(Photograph courtesy of Fiber Glass Systems and Fiberglass Solutions Inc)

8.2 Spoolable Pipe

Joining spoolable pipe relies on the installation of metallic couplers (to connect pipe
lengths) and fittings (to provide a flange transition at the pipeline end points) to connect
to above-ground piping.
Each spoolable pipe product has unique connections and often these require installation
by the manufacturer’s representative, or in some cases third-party contractors certified
by the manufacturer. Joining personnel should be qualified before the start-up of any
spoolable pipe project.
Some RTP products utilize a vent port at the metallic connectors to allow any permeated
gas to vent. It is important that these vents are positioned away from water entry
sources. Manufactures should be consulted for the location of vents, use of threaded
vent hole, and design of vents, e.g. either in the ground or at surface.
If the pipeline is in H2S containing service, the vent gas properties must also be
considered in terms of location of the vented connections, vent procedures or possible
use of a chemical scavenger to scrub vent gas.

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 The CSA Z662-19 requirements specified above for stick composite pipe also apply to
spoolable pipe. It is also very important that inspectors are fully aware of the joining
procedure, inspection and test plan requirements.
Where internal corrosion is a concern, additional protective coatings or use of CRA
couplers are possible considerations. Generally, spoolable pipe manufacturers offer
their couplers with a protective coating or in a range of CRA materials.
CSA Z662-2019 requires steel portions of non-metallic pipeline systems to have external
corrosion protection. This includes external coating along with CP for underground steel
couplers, transitions and risers. The CP design should be discussed with the
manufacturer to determine the options for external coatings and CP anodes. The use of
CP may not be required where solid CRAs or CRA metallic coatings are used; however,
the application of a tape wrap is generally advised for protection against any harmful
soil contaminants such as chloride.

Figure 8-2 Metallic Coupler Joining Sections of Spoolable Pipe

(Photograph courtesy of FlexSteel Pipeline Technologies Ltd.)

8.3 Inspection Test Plan

CSA Z662-19, Section 13.1.7 specifies that an inspection and test plan (ITP) be used for
quality control of the joining procedure. The ITP is based on the manufacturer’s
approved joining procedure and quality control requirements.

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 Several areas that must be covered in the inspection plan are the approved thread
compounds, approved make-up tools, and thread makeup procedure. Normally,
threaded pipe is made to a specified thread position rather than a specified torque
value.
Visual inspection requirements should also be detailed for specialty fittings installation,
crimping and fit-up.
Non-destructive testing methods such as x-ray or ultrasonic inspections of completed
pipe joints, as used for steel pipe welds, is not currently possible for composite pipe
joints. Therefore, the joining process must be carefully performed correctly by joining
personnel and monitored by field construction inspectors to ensure success.

9 Pressure Testing

9.1 New Construction

Following construction, the pipeline must be pressure tested to verify integrity and
prove that no joint leaks exist as per CSA Z662-19 requirements. For instance, the
specified minimum test pressure should be 125 per cent of the design pressure for the
pipeline. In some cases, such as gas containing H2S, the local regulatory body can
request a higher-pressure test requirement.
The maximum hydrotest pressure must be within the specification of the pipe
manufacturer and be verified as acceptable.
Note: The effect of elevation changes must be considered and included in the pressure
test procedure and not cause the maximum allowed pressure limitation of the pipe
manufacturer to be exceeded.
Further, the minimum test duration is eight hours when testing with water or 24 hours
for pneumatic tests—pneumatic tests are limited to a maximum test pressure of 2,900
kPa. These preliminary pressure tests are used to verify joining procedure and quality as
the construction proceeds.
Recommendation:
Pneumatic preliminary leak testing is not recommended due to safety concerns related
to the high potential energy involved and associated harm that may be caused by a joint
failure.
In some cases, for stick pipe installations, the pipeline may be partially backfilled and
tested with the connections only left exposed. This approach allows for the pipe joints
to be visually inspected for any leaks and repaired before the pipeline is fully backfilled.
Where the preliminary leak test is successful, the test fluid is left in the pipe during
completion of backfilling, followed by a second final pressure test.
For preliminary leak tests, the pipe body should be restrained in the trench to resist
lifting and possible damage while the pipe is pressurized. This is often accomplished by

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 placing soil plugs in the centre area of each pipe while leaving the joints exposed for
leak assessment.
Soft pigs approved by the pipe manufacturer may be used when filling the pipeline with
pressure test fluids. The use of freeze point depressants during winter construction is
also acceptable if approved by the manufacturer and local regulatory bodies.
As for any pipeline pressure test, the pressure should be raised in increments with
several hold points before setting at the test pressure. Non-metallic pipe materials will
react differently than steel to stress and temperature variations. A stabilization period
may also be required before starting the pressure test if the test fluid and pipe initial
temperatures differ significantly.
The pipe manufacturer’s pressure testing procedure should be consulted and applied
during the development of the pressure test procedure for pipeline projects.
If a leak is detected during the testing, it must be repaired, and the pipeline re-tested at
125 per cent of the design pressure for the full specified duration.

9.2 Pressure Testing Repairs (Operating Pipelines)

In accordance with CSA Z662-19, pressure testing is required for any repairs performed
on existing operating pipelines. Testing of tie-ins must be performed over a four-hour
duration (at minimum) at the highest available normal operating pressure with the
repaired pipe section left exposed. This is meant to allow for tie-ins of pretested pipe to
be pressure-tested using service fluid under operating pressure.

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10 Operation

10.1 General
In general, the operation of a reinforced composite pipeline is similar to the operation
of a conventional steel pipeline system. However, several differences exist that
operation and maintenance personnel should be aware of, to ensure the pipeline is not
operated outside its design limits. To increase awareness, field signage can be used to
highlight the locations of reinforced composite pipelines.
Instruments such as pressure or temperature sensors are not normally installed or
mounted directly on non-metallic pipe but are incorporated into steel piping or
wellhead facilities located at ends of the pipeline.
For some RTP spoolable pipe products, vent ports are installed at the metallic
connections and are provided to allow permeated gases to freely vent off from between
the inner thermoplastic liner and outer reinforcement layers. The annular venting
system gives the end user the capability of capturing the permeated gases, resulting in
zero emissions.

10.2 Pressure
The pressure control, limiting and relieving systems of reinforced composite pipelines
are similar to those used for steel pipelines. However, composite pipes carry a greater
sensitivity to pressure cycles and as such have additional design factors specified at the
design stage. Also note that not all stick or spoolable composite pipe products react the
same to highly cyclic service conditions. Some products are much more resistant than
others.
In the design stage this should be evaluated based on product review and considered
during product selection.
In CSA Z662-19 there is a requirement to apply an additional design factor supplied by
the pipe manufacturer based on their product testing, when severe pressure cycles or
surges exist—in general when then the operating pressure cycles are greater than ±20
per cent of the design pressure. During their lifespans, all pipelines will experience some
degree of pressure cycles at start-up or shutdown, which normally do not present great
concern. However, when reinforced composite pipelines are operated with repetitive
ongoing pressure cycles, the initial design pressure should be de-rated by the cyclic
pressure factor.
An example of when the design pressure must be de-rated would be a situation in which
water injection pumps are stopped and started several times per day and the pipeline
pressure is allowed to cycle outside the ±20 per cent criterion. In addition, pumping
wells utilizing a pump jack could in some cases generate excessive cyclic pressures.

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 Pipeline operators should be made aware of this increased sensitivity and be vigilant
whenever severe pressure cycling conditions exist. The pipe manufacturer should also
be contacted for further advice on the acceptability of cyclic pressure operation.
Other aspects to monitor include any pressure surges or pump pulsation conditions that
may damage composite pipe over time. In most cases, pulsation dampeners are
installed downstream of pumps. The effectiveness of the pulsation dampeners should
be regularly monitored, and their units maintained as recommended by the
manufacturer.

10.3 Temperature
Maintaining reinforced composite pipelines within the specified operating temperature
is very important during operation. In general, excessive temperature is one of the
leading causes of advanced plastics degradation, which is made more complex by the
variety of available pipe products and the different maximum rated operated
temperatures associated with each.
The temperature rating of stick composite pipe—which can vary from 65C to 100C or
higher—is primarily based on the type of resin used. The effect of temperature on the
design pressure should also be considered. For example, some composite pipes will
have a specified pressure rating at 65C and a reduced rating at a higher temperature
such as 90C. Operations personnel must therefore be made aware of the design basis
that was actually used rather than relying on the manufacturer’s maximum temperature
rating.
The temperature rating for spoolable pipes is mainly based on the inner liner material,
most often HDPE Grade PE 4710. Most spoolable pipe manufacturers restrict pipe with a
standard HDPE liner to 60C; however slightly higher temperature ratings up to 90C
may be allowed depending on service fluid conditions. Alternate liner materials—such
as PE-RT, PEX, PA—may be installed and also affect the temperature rating. The pipe
manufacturer should be consulted when any uncertainty exists regarding the pipe’s
temperature rating.
Using hot-oiling to remove wax deposits should be performed very carefully and stay
well within the pipeline’s design temperature.
Low-temperature operation of spoolable pipe products must also be carefully
considered due to the relatively high glass transition temperature of HDPE. Where
exposure to low temperature is possible, for example during winter start up or under
Joule-Thomson cooling effects due to gas expansion, careful consideration must be
given to the increased brittleness of the pipe. Any accidental mechanical impact to the
pipe must be avoided especially when pipe temperatures are low.

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10.4 Pigging
Pigging is possible in non-metallic pipelines; however, pigs should be restricted to softer
rubber cups (80 or 60 durometer) or foam styles without any metal components. Most
pig suppliers or pig manufacturers have product lines that are suitable for reinforced
composite pipelines.
An important factor to consider when selecting a pig is the different internal pipe
diameters that exist for various reinforced composite pipe products. Do not assume that
a NPS 3” pig sized for a steel pipeline is suitable for a NPS 3” composite pipe product as
the internal diameters may vary significantly and resulting damage to the composite
pipe can occur.
When selecting pig styles or sizes, consideration should be given to the restrictions
introduced by the heavier wall risers and the couplers. The pig selection must take into
account the pigging requirements for specific lines. Slug removal may require higher
pushing pressures then what foam pigs can withstand. Similarly, the presence of sand
can significantly reduce the life of the pigs and also jeopardize the integrity of the pipe
when sand particles are trapped between the pig and the pipe wall. To avoid these
issues, pig criteria such as a maximum cup oversize, specific durometer and specialized
multi-cup design should be evaluated.
In all cases, the reinforced composite pipe manufacturer should be consulted for pigging
procedures and approved pig products. Ball style pigs or pigs with metal bodies should
not be used. It is recommended that reinforced composite pipelines have additional
signage placed at pipeline ends to alert operators.

10.5 Chemicals
As stated in Sections 4 and 5, the use of chemical additives must be carefully
considered, and their compatibility verified with the pipe manufacturer before
introduction to the pipeline.
The concentration of chemicals in the pipeline service fluid is important to consider as
well since at very low concentrations the chemical may be acceptable but not at higher
concentrations. Some of the typical oilfield chemicals that may be harmful include:
• Methanol;
• Strong hydrocarbon solvents such as benzene, toluene, xylene, cyclo-
pentane, cyclo-hexane;
• Acids (including spent acid flow back);
• Corrosion inhibitors;
• Scale inhibitors ;
• Sulphur solvents such as dimethyl disulphide (DMDS).
The effect of chemicals on stick composite pipe may be different than the effect on
spoolable pipes since different materials are involved. In most cases, the effect of
additive chemicals may be minimal if the chemical is only a spot treatment and

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 exposure to the pipe is very short (e.g., a few seconds). The chemical application
temperature must be considered in determining possible effects of exposure. Possible
chemical carryover from chemical injection at upstream facilities and wells must also be
considered.

10.6 Deactivation or Abandonment

CSA Z662-19 clause 13.1 states that where reinforced composite pipelines are being
considered for deactivation or abandonment an assessment should be done of potential
hazards from gases that may evolve from the pipe material. These could be gases that
have been absorbed by the pipe material and de-absorb over time and be released.
Normally the primary concern is with any presence of absorbed H2S. Therefore, some
repeated purging to remove de-absorbed gases, with rest periods might be necessary,
based on monitoring of gas levels or other observations.
Other consideration would be to ensure the pipeline is emptied of all service fluids
normally accomplished by pigging these out of the line.
Water, if allowed to freeze, may damage reinforced composite pipe. In this regard stick
pipe may be more vulnerable to damage than spoolable pipe, however the particular
pipe manufacturer should be consulted for more information on sensitivity to freeze off
of their pipe product.
Ongoing corrosion or degradation of the reinforced composite pipe is not normally an
issue but any steel connected facilities such as risers would need to be considered in
terms of ongoing preservation from internal or external corrosion, where required.

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11 Reinforced Composite Pipelines Repairs

11.1 Stick Pipe Repairs

In general, repair of a high-pressure composite pipe that utilizes threaded connections
will involve installation of a flange set. This is accomplished by removing the damaged
pipe as a cylinder with cut back to the undamaged pipe provided. In some cases, the
field installation of a thread by molding can be accomplished on each end of the pipe
and threaded flanges.
After cutting, the entire threaded pipe joint may be removed, in some cases by
unthreading each of the cut pipe ends. Following this, a pre-fabricated pipe joint—
designed to replace a full pipe joint including a flange set—can be installed.
If lower pressure pipe with adhesive bonded connections is involved, the use of bonded
repair collars with a replacement short pipe section may be employed.
Using GPS to record the location of the pipe repair areas is recommended. Tracer wire
must be continuous through the repair site.
Pipe manufacturers provide detailed repair methods in their manuals and should be
consulted whenever a repair is required for their product.

11.2 Spoolable Pipe Repairs

Spoolable pipeline repairs normally involve cutting a section of pipe, typically three to
four metres in length or as specified by the manufacturer. At this point, all damaged
pipe should be removed.
Note:
Damaged pipe layers may have been exposed to pipeline service fluid with
some ingress into the adjacent pipe. In these instances, additional pipe length
may be required to be cut back to ensure full removal of the service fluid.
Once the repair length has been removed, pipe couplers can be installed on each cut
end and the new pretested pipe repair section installed into the couplers.
Recommendation:
The repair couplers for each spoolable pipe product are unique and cannot be
interchanged between different pipe products or pipe of different pressure ratings. As
such, it is recommended that the pipe manufacturer’s field service crews be on site for
all repairs and in some cases to conduct the repairs themselves.
As with stick pipe repairs, the use of GPS to locate pipe repair areas is recommended.
Tracer wire must be continuous throughout the repair site.

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11.3 Excavation for Repairs
Any excavation of reinforced composite pipe requires extra care to avoid further
damage to the pipe. When excavating, the use of probes must be done carefully to
prevent damage to the pipe below. Use of probes is acceptable, but they should not
have sharp ends and should be pushed into the soil carefully.
Hydro-vacuum excavation is commonly used but can also damage pipe by erosion if not
done carefully. To avoid damage, the hydro-vacuum contractor should be notified that
the pipe material is not steel. In some cases, the use of a multi-nozzle head with
dispersing flow—as opposed to oscillating and rotating flow—may be used to avoid
mechanical abrasion of the pipe. Maintaining a lower water pressure and temperature
than those used for steel are other measures to be considered and discussed with the
hydro-vacuum contractor before this excavation method is used. The pipe manufacturer
should also be consulted for their guidance on hydro-vacuum operations.
Hydrovac or air-vac operations should use operating procedures approved by the
operating company. The procedures should document as a minimum, wand tip styles,
and limits on water pressure and temperature.
Note: If the outer protective layer of composite material is perforated, the
inner reinforcement layers can be damaged or weakened by exposure to
groundwater.

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12 Operations Monitoring

12.1 Leak Detection

Leak detection methods such as fluid balance, pressure monitoring, and right-of-way
patrols are generally no different than standard methods employed for steel pipelines.
Infrared pipeline leak detection methods using airborne surveillance would also be
expected to function similarly for non-metallic pipelines as for steel pipelines. However,
sound transmission in non-metallic pipe will be at a different velocity than steel. As
such, leak detection methods using acoustic transmission will need to be reviewed with
the leak detection manufacturer to determine suitability for non-metallic pipe.
Routine pipeline right-of-way surveillance should also be performed looking for any of
the usual anomalies such as washed-out areas, soil slumps, and evidence of fluid leaks.

12.2 Cathodic Protection (CP)

External corrosion protection is required where steel couplers or steel pipe risers are
installed in combination with reinforced composite pipelines, which is typically
accomplished by providing an external coating as previously discussed.
CP is also required and is usually accomplished by installing a sacrificial anode designed
to last throughout the project.
CSA Z662-19, Section 13.1.2.16 specifies that for steel underground couplers or risers,
CP be installed. Monitoring of CP on risers is required. Where solid corrosion resistant
alloy or metallic coated fittings are used, CP is not required based on an engineering
assessment.
The ability to monitor the CP performance may not always be possible for underground
couplers and is optional; however, this can be accomplished by installing test leads from
the steel equipment and anode. This issue requires operator consideration through
discussion with the pipe supplier and local regulators regarding the need for CP and
ongoing monitoring.

12.3 Pressure Cycles

As previously discussed, excessive surge pressure cycles may be damaging to reinforced
composite pipelines. CSA Z662-19 specifies pressure cycle ranges and requires their
consideration for pipeline design pressure. Operators should therefore periodically
perform and review the actual operational pressure cycles and temperatures being
experienced to ensure these are within the initial criteria used for design of the pipeline

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12.4 Temperature Effects
Operation of reinforced composite pipes above their maximum rated temperatures is
one of the most damaging things an operator can do. All plastic polymers degrade,
referred to in the industry as ageing.
Pipe requires good resistance to the service environment, water and other substances.
In general, chemical components become more aggressive at higher concentrations and
elevated temperatures. The performance of reinforced composite pipe will degrade at
elevated temperature.
Qualification of composite pipe is done at elevated temperature. Usually the maximum
temperature rating, and the allowable design stresses are determined based on a
lifetime of 20 years. If the testing was done at higher temperature the allowable stress
would be lower.
For stick pipes, the effect of temperature ageing is to progress a degradation of the pipe
wall structure and cause increased absorption of water or other fluids into the wall
matrix structure and cause damage. The pipe wall is a bonded laminate of epoxy resin
and glass fibres and depends primarily on the strength of that bond to perform over its
intended life. Ingress of water will weaken the bond and lead to a loss of mechanical
properties.
The rate of water ingress is temperature dependent and controls the rate of laminate
degradation. Therefore, the effect is to shorten the life expectancy for the pipe.
For RTP composite pipes that utilize dry glass winding reinforcement, the effects of
water ingress are increased since the glass is not encapsulated and protected by epoxy
resin. Water ingress and exposure to fibreglass windings can significantly lower the glass
tensile strength. Cases have been seen where water ingress has occurred to composite
pipe while in storage in a wet environment. The manufacturer should be consulted for
guidance on procedures for checking for possible wet fibres.
For SCP/RTP spoolable pipes the reinforcement layer is more effectively isolated from
the service fluid. However, these products all utilize an inner thermoplastic liner, usually
HDPE. The liner properties are directly linked to temperature. The liner properties will
lower significantly with temperature. For example, HDPE loses approximately 50 % of its
mechanical strength at 65oC compared to room temperature and may become more
vulnerable to collapse or tearing stresses.
SCP pipes rely on a bonded outer laminate, therefore high temperatures especially
combined with the presence of water may be damaging and reduce pipe life at elevated
temperatures that exceed the maximum rating.

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13 Operations, Maintenance and Integrity

13.1 Non-destructive Testing

The options for non-destructive examinations of reinforced composite pipelines are
much more limited than for steel pipelines. In some cases, radiography has been used to
examine stick pipe to identify any signs of delaminating of the pipe wall.
For spoolable pipe, bell-holes may be installed at metallic coupler sites—especially if
they contain a valve or tee fitting—which would allow for periodic radiography or
ultrasonic inspection of the couplers.
Evisive microwave transmission (EMT) is a NDE technology that is being explored for the
examination of reinforced composite pipe. Consultation with experts familiar with this
technology may assist in determining condition of in-service pipe without the need to
perform cut-outs.

13.2 Pressure Testing

To verify the integrity of a reinforced composite pipeline, the use of a pressure test may
be considered depending on the situation. When pressure testing in-service pipelines, it
is prudent to maintain the pressure test at or below the pipeline design pressure. In
some cases, the test may be performed using the pipeline service fluid; however, the
associated risks must be fully evaluated on a case-by-case basis by the pipeline
operator. Usually, if the pipeline service fluid contains a significant vapour phase it will
likely not be suitable for pressure testing due to the lack of accuracy and sensitivity to
small leaks.

13.3 Pipeline Risers

Pipeline risers may provide an accessible location to perform inspection. If the riser end
can be opened, visual inspections may be possible using lights or reflective mirrors to
view the pipe’s interior.
Tethered video recording cameras have been used by some operators to internally
inspect pipe through access at risers. Visual anomalies such as liner
collapse/deformation and pipe wall damage may be located. The length of the inspected
pipe is limited. A boroscope optical instrument can also be used at risers to view the
pipe’s internal surfaces and provide an assessment of the surface condition.

13.4 Pipe Cutouts

Any pipe sections that have to be removed should be sent for analysis of properties and
appearance—analyses can be provided by pipe manufacturers or independent
laboratories. Lab analysis should provide an indication of how the pipe is standing up to
the service environment.

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 For spoolable composite pipes, burst testing of removed pipe samples provides a
method of integrity assessment. Pipe manufacturers all rely on this method. Additional
testing of pipe samples to measure pipe properties allows a comparison of existing
versus the specified new pipe properties.
For pipes that utilize dry fibre reinforcement, removed samples can be dissected and
the fibres inspected for signs of mechanical damage or water ingress.

13.5 Integrity Management

Similar to steel pipeline systems, the integrity management of reinforced composite
pipeline systems must be addressed by pipeline operators. However, the methodology
for prioritizing inspections and risk ranking of pipelines must be approached somewhat
differently.
For baseline information, general awareness of failure causes and contributing factors
based on the industry failure statistics for composite pipelines are helpful. Knowledge of
the general failure mechanisms experienced can be used. Local area operating history
can also be incorporated into integrity management planning.
Management of change (MOC) must be practiced when pipeline installations have
changing service conditions that may be outside the initial design criteria. An example
would be changing out a producing oil well from a sucker rod pump to a downhole high
volume electric submersible pump (ESP) that could significantly increase temperature,
volume of fluids and different pressure cycling on/off and start up conditions.
As stated previously in this document, in general, reinforced composite pipelines are
more vulnerable to mechanical damage caused by excessive soil induced stresses.
Therefore, in geographic areas where poor soil stability, very wet soil conditions and
muskeg are present, pipe damage may pose a greater risk than in areas where flat and
drier terrain is present. Often this damage will manifest itself near risers where greater
soil disturbance and over-excavation may have occurred during the pipeline installation.
Operating factors that can increase the risk of pipe deterioration for reinforced
composite pipelines include
• High temperature operation,

• Cyclic pressure operation, and

• Higher pressure operation, with the presence of a small margin difference (e.g.,
<10%) between the operating pressure and the manufacturer’s MPR.

Generally, low-pressure rated stick pipe with thinner walls may be more vulnerable to
damage than high-pressure rated, thick walled pipe.
Spoolable pipes—due to their inherent flexibility—are generally less prone to
mechanical damage than more rigid stick pipe. However, the spoolable pipes may be
prone to impact damage or damage at risers or couplers where stresses are often highly

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intensified. Lack of pipe support at above-ground risers connections, causing higher
loads on the spoolable pipe, has led to industry failures.
The integrity of spoolable pipelines may also be monitored through checks for fluids
present at annular space vent holes, typically installed at metallic fittings and couplings.
Where steel pipe segments for risers or couplers are present, corrosion of the steel pipe
sections must be considered for integrity management. In terms of temperature, the
margin between the pipe maximum temperature rating and the actual operating
temperature of the pipeline can be considered. A larger margin would tend to lessen
risk of premature pipe degradation for the same pipe in a given set of service
conditions.
The presence of routinely occurring pressure cycles or high surge pressures in a pipeline
system can lead to premature pipe degradation. This mode of operation should be
reviewed with the pipe manufacturer as the effect on the pipe’s integrity may vary
based on the particular pipe involved and the overall severity of the pressure cycles
(amplitude and frequency). Often, where positive displacement water injection pumps
or high-volume submersible pumps are installed that regularly cycle on and off—severe
pressure cycles in the pipeline system may exist that can lead to the premature
degradation of reinforced composite pipes. Both stick and spoolable pipe types may be
vulnerable to high-cyclic pressure services due to reinforcement fibre or laminate
damage. Operators should review and discuss any high-cyclic pressure operation of
reinforced composite pipelines with the pipe manufacturer as the effect may vary
depending on the pipe product and the operating circumstances involved. Consideration
to electrical power bumps in an operation region should also be weighed during the
design and material selection phases of the project.
The remaining life of a pipe that has experienced cyclic service is difficult to determine
and often requires a combination of destructive testing and risk analysis to evaluate
probability for future failures (terrain, production being carried, environmental clean-up
and habitat concerns, etc.). Remaining life assessments can involve burst testing
adjacent pipe samples in coordination with failure analysis of the individual fibre glass
layers and epoxy resins. Consideration can be given to applying additional service
factors to the maximum pressure rating of the pipe after a failure has occurred. This
approach may be justified as the remaining life on the non-metallic pipe that has
undergone an excursion will be different then the remaining life determined through
the LTHS values originally calculated in material qualification test procedures, using
ASTM D 2992 and normal operating parameters.
Recommendation:
See API RP 15SA18, published by API that is a recommended practice for the integrity
management of spoolable reinforced line pipe.

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14 References
1. Canadian Standards Association, 2019. CSA Z662-19, Oil and Gas Pipeline Systems.
2. Alberta Energy Regulator (AER), 2021. Annual Pipeline Performance Report, Online Publication at the following
address: https://www.aer.ca/protecting-what-matters/holding-industry-accountable/industry-
performance/pipeline-performance
3. NACE International, 2007. SP0178, Standard Practice for Design, Fabrication, and Surface Finish Practices for
Tanks and Vessels to Be Lined for Immersion Service.
4. Alberta Energy Regulator (AER), 2021. Directive 056 Energy Development Applications and Schedules.
5. Alberta Energy Regulator (AER), 2021. Manual 012, Energy Development Applications - Procedures and
Schedules
6. ASTM International, ASTM D 3839-2014 (2019), Standard Guide for Underground Installation of “Fiberglass” or
(Glass Fiber Reinforced Thermosetting Resin) Pipe.
7. American Water Works Association, 2013. AWWA Manual M45, Fiberglass Pipe Design.
8. ASTM International, ASTM D 2996-2017, Standard Specification for Filament-Wound “Fiberglass’’ (Glass-Fiber-
Reinforced Thermosetting-Resin) Pipe.
9. International Organization for Standardization, 2017. ISO 14692, Parts 1-4, Glass Reinforced Plastics (GRP)
Piping.
10. American Petroleum Institute, 2022. API 15S, Spoolable Reinforced Plastic Line Pipe.
11. Canadian Standards Association, 2014. CSA Z245.30-22, Field-applied External Coatings for Steel Pipeline
Systems.
12. American Petroleum Institute, 2016. API 15HR (R2021), Specification for High Pressure Fiberglass Pipe.
13. ASTM International, ASTM D 2992-2018, Standard Practice for Obtaining Hydrostatic or Pressure Design Basis
for “Fiberglass” or (Glass-Fiber Reinforced-Thermosetting-Resin) Pipe and Fittings.
14. American Petroleum Institute, 2016 API 17J (R2021), Specification for Unbonded Flexible Pipe.
15. American Petroleum Institute, 2021. API RP 15SIH, Installation and Handling of Spoolable Reinforced Plastic
Line Pipe.
16. American Water Works Association, 2020. AWWA Standard C950, Fiberglass Pressure Pipe.
17. ASME International, 2020. ASME B 31.1, Process Piping.
18. American Petroleum Institute, 2022. API RP 15SA, Integrity Management of Spoolable Reinforced Plastic Line
Pipe.

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Appendix A. Abbreviations and Acronyms

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A.1 Abbreviations and Acronyms

Acronym Description
CP cathodic protection
CRA corrosion-resistant alloys
ENC electroless nickel coating
HDPE high-density polyethylene
LTHS long-term hydrostatic strength
MPR maximum pressure rating
MAOT maximum allowable operating temperature
NDE non-destructive examination
PA polyamide
PE-RT polyethylene-raised temperature
PEX cross-linked polyethylene
PTFE poly-tetra-fluoro-ethylene
RTP reinforced thermoplastic pipe
SCP spoolable composite pipe
VFD variable frequency drive

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Appendix B. Material Selection Guide

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A.2 Reinforced Composite Pipe Options- Temperature (T)/Diameter (D)/Pressure (P) Manufacturers Ratings
Guideline
X = Product Available
T T>60C T D D D P P>5.0 MPa P>10.3 MPa P>15.5 MPa P>17.2 MPa
Pipe Type Pipe <60C T< 80C <100C ≤NPS 4 ≤NPS 6 <NPS 8 < 5.0 MPa P<10.3 MPa P<15.5 MPa P<17.2 MPa P<20.6 MPa
Description (ANSI 600) (ANSI 900)

Spoolable: RTP- Dry Fiber X X X X X X

with PE 4710
RTP HDPE Liner Note 3
Reinforced
Thermoplastic
Pipe SCP- Bonded X X X X X X X X
Glass Fiber to
PE4710 HDPE Note 3 Note 4 Note 4
SCP Liner
Spoolable
Composite RTP- Steel X X X X X X X X X X X
Pipe Strip or Wire
with PE4710 Note 6 Note 6 Note 3 Note 5 Note 5 Note 5
HDPE Liner

Stick Pipe: Bonded glass X X X X X X X X X X X

fiber, epoxy Note 1 Note 1 Note 1 Note 2 Note 2 Note 2 Note 2 Note 2 Note 2 Note 2 Note 2
Fibreglass resin matrix Note 3
Reinforced
Pipe (FRP)

Note 1: Temperature rating is based on the epoxy resin type used for manufacturing, not all rigid composite pipes are rated for the same service temperature, check with
pipe manufacturer. Pressure derating factor may be applicable for services above 90oC.
Note 2: Pipe diameter may limit available pressure ratings; generally larger diameter pipes will have lower pressure ratings availability.
Note 3: For gas gathering pipelines the maximum design pressure is restricted to 9.93 MPa by CSA Z662-2019 and maximum H2S content in the gas is 50 kPa partial
pressure. Local regulator may have more stringent requirements. More stringent AER requirements for H2S services are provided within Directive 056. See Table 3-3 for
summary of Directive 056.
Note 4: Bonded glass reinforced pipe (SCP) available in NPS 2,3,4 to 17.24 MPa pressure rating, and NPS 6 to 10.34 Pa pressure rating.
Note 5: Steel strip reinforced pipe (RTP) available in NPS 2-6 to 20.7 MPa, NPS 2-8 to 15.5 MPa pressure rating.
Note 6: Steel strip reinforced pipe (RTP) is manufactured with PE-RT Liner in this temperature range and is rated up to 90°C depending on the application.

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