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March
2017
HYDROCARBON
ENGINEERING
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outdoor equipment, even very small gaps in
insulating cladding can allow in enough water to
cause significant corrosion issues.
Another challenge created by insulation is that it
can hide the effects of the corrosion from view, so
that a heavily corroded pipe can appear normal
when visually inspected. By the time the effects are
visible from the outside – often in the form of
particles of oxidised metal or discoloured water
running off – significant damage has already been
done.
Removing insulation to check the condition of
pipework is a laborious process and a costly method
of assessing the condition of an asset. This makes it
one of the first areas to receive less attention when
budgets get tight, but it is a cut that companies
cannot afford to make. With this in mind, specialists
in the offshore sector have developed a number of
different solutions that can make managing CUI
across an installation more efficient and help ensure
pipes and structures conform to health, safety and
environment (HSE) guidelines.
End-to-end efficiency
The biggest cost associated with corrosion
inspection is manpower. When offshore facilities are
involved, that includes the process of getting the
right personnel on board and ensuring that they
receive the correct briefing, which can be a time
consuming process. However, this argument is also
true for downstream facilities, where giving the right
personnel access to the site can involve long
distance travel, accommodation costs and
certification issues.
The focus is therefore on minimising resources
needed to carry out the work. At Bilfinger, this is
tackled by having inspection and fabric maintenance
departments work together, using three man
multi-skilled teams that include an inspector,
insulator and painter, all of whom are rope access
qualified. Keeping the teams as small as possible can
lead to considerable cost reductions. It is better still
if one can avoid transporting new personnel to site
to carry out an inspection altogether, by training
team members that are already on location to carry
out the inspection work.
Getting smart with detection
technology
There have also been significant technological
advancements in recent years that have increased
the efficiency and effectiveness of inspection crews.
Ensuring teams are equipped with the latest
advanced CUI detection tools, such as digital
radiography and pulsed eddy current (PEC)
technology, is another vital aspect of speeding up
site inspection processes and improving the
likelihood of early detection. There is now a lot
more that can be done to detect hidden corrosion
than simply carrying out visual detection. Using
advanced imaging techniques, which make use of
non-visible electromagnetic effects to detect the
condition of pipework, can indicate issues earlier
and more reliably.
While both radiographic and PEC imaging have
been known about for a long time, the technology
used to carry out inspections has advanced rapidly
in recent years. Where once each radiographic
exposure took several minutes to capture and
subsequently needed to be processed using
laboratory equipment, these can now be carried out
in a matter of seconds, providing images to view
instantly on a mobile device.
Similarly, while PEC readings as recently as
five years ago needed to be carried out on a
point-to-point basis, making it time consuming to
capture all of the angles and positions required to
scan a length of pipework, the latest systems
developed by Eddyfi run continuously. This reduces
the time taken and significantly increases the
number of data points available, providing greater
certainty of results. Implementing these advanced
detection techniques will always involve a large
element of data analysis and interpretation. Finding
an efficient way of carrying this out is essential in
delivering an efficient end-to-end service.
The power of portable technology today means
that this process can now often be carried out on
the ground, rather than needing to save or relay data
for desktop analysis later. Portable digital solutions
put a wide range of functionality at the inspection
engineer’s fingertips by incorporating a large
touchscreen and extensive battery life to allow
performance through a shift. Combining the required
features with a robust design often means the units
can be larger than a handheld unit, so a well
designed harness to allow comfortable extended use
is also critical.
The software embedded in this technology can
facilitate the whole process, from setting up a new
inspection regime to conducting the examination
and generating detailed reports. Now that engineers
are able to output easy to interpret condition
reports, clearly showing the location and extent of
any defects without any subsequent need to analyse
the data, the ability to respond rapidly to other
urgent situations is increased. For many inspections,
dependence on rope access can also be reduced by
using un-manned aerial vehicles (UAVs) – or drones.
Once the presence of CUI has been identified, an
efficient strategy for replacing affected insulation is
essential.
Case study
Bilfinger was called in by a contractor operating a
platform for a major global energy company to
renew the insulation on all exterior pipework where
CUI was detected. The existing insulation on the
pipework was mineral wool, enclosed in neoprene
cladding, and the cause of the CUI in every case was