API 15S. The pipe can be spooled for continuous pipe lengths
ranging from 591 ft (for the 8 in. dia. pipe) up to 6578 ft (for the
2 in. dia. pipe). Longer lengths mean fewer connections and
consequently, faster installation. Since connections can be points
of increased vulnerability along a pipeline, reducing the number
of connections also reduces the number of potential leak paths.
Material selection
The strength of the FlexSteel pipe structure is provided by the
steel reinforcement, which consists of contra-wound sets of steel
strips applied over the liner. The steel used in the reinforcement
layer is a widely available commercial grade with excellent
strength in both pressure containment and axial load bearing
capability. An alloy steel grade is available that provides excellent
resistance to sulphide stress cracking and hydrogen induced
cracking.
The corrosion resistant liner and the corrosion resistant shield
are produced from a high density polyethylene compound with
carbon black additions for resistance to ultraviolet radiation.
A white masterbatch has been developed for more extreme
temperature and UV exposure in unburied desert applications.
The white pipe has withstood over 10 years of outdoor exposure
in a North American desert and accelerated weathering tests
replicating 20 years in an Oman desert.
Qualification testing
Qualification testing is conducted on all flexible steel pipe
designs to ensure pipe integrity:
)
)
Burst tests verify that the flexible steel pipe meets design
criteria.
)
)
Axial tension testing provides practical limits during
installation.
)
)
Collapse pressure tests determine the maximum water depth
for marine applications.
)
)
The end connection accelerated life test uses elevated
temperature to accelerate creep and stress relaxation of the
thermoplastic layers within the end connection to ensure a
leak-tight connection.
Product success
Within two years of being introduced to the market, FlexSteel’s
steel reinforced spoolable pipe won the prestigious “Enbridge
International New Pipeline Technology Award” at the inaugural
International Pipeline Awards held at the 2006 International
Pipeline Exposition, Calgary. This award was presented to the
company who, in the opinion of the judges, had contributed
significantly to the development of the pipeline industry. The
product gained momentum quickly, requiring FlexSteel to add a
second manufacturing plant to keep up with the market demands
for production.
The company was also honoured with the “2013 Plastics
Pipe Institute Energy Piping Systems Division Project of the Year
Award” at the PPI’s Annual Meeting. The highly competitive
award pays tribute to innovative installations and uses of
polyethylene (PE) pipe throughout the USA. PPI selected
FlexSteel for the award because a project in which 16 900 ft of
its newly developed 8 in. dia. 1500 psi pipeline was installed to
transport water to a drilling site in the mountainous terrain of
the Marcellus Shale Basin. The 8 in. steel reinforced polyethylene
flexible pipeline was installed in one-third of the time of
traditional steel pipe alternatives and delivered a variety of
critical cost-saving and performance benefits.
More recently, FlexSteel pipe has been selected for use in
Australia’s high profile Carnegie Wave Energy Project. Supported
Figure 7.
Spoolable pipe deploys quickly along a narrow right
of way.
Figure 8.
Flexible
steel reinforced pipe
structure.
60
World Pipelines
/
JANUARY 2015
Figure 6.
Steel reinforcement can also provide the required
weight for negative buoyancy. (Photograph courtesy of
Carnegie Wave Energy).
