A corrosion survey was conducted at areas of
concern on a 4-inch line, using digital radiography
T E S T I N G
CORROSION UNDER
INSULATION SERVICES
The costs of corrosion
for companies and
the economy can be
astronomical. According to
National Association of Corrosion
Engineers (NACE) International:
“The global cost of corrosion is
estimated to be US$ 2.5 trillion,
which is equivalent to 3.4% of the
global gross domestic product
(GDP 2013).
By using available corrosion control
practices, it is estimated that
savings of between 15 and 30%
of the cost of corrosion could be
realised i.e. between US$375 and
$875 billion annually on a global
basis.”
A big challenge for the food
industry is corrosion under
insulation (CUI), which occurs when
halogen compounds (compounds
of chlorine, bromine, or fluorine)
become trapped with moisture in
the insulation material, corroding
even stainless-steel piping.
Not only is corrosion a major drain
on business finances, it also poses
a threat to health and safety, an
example of which is Ammonia
refrigeration pipework. According
to a technical bulletin issued by
WorkSafe, the uncontrolled release
of ammonia from a refrigeration
plant is a critical work health
and safety risk, which must be
managed effectively to minimise
the risk of harm. It reported that in
2017, approximately 20 ammonia
releases were notified to WorkSafe
New Zealand, highlighting the
importance of risk assessments
and implementing appropriate
control measures. In the bulletin,
they highlight two main causes of
ammonia release, one of which
is equipment failure, including
corroded pipework.
Stork, a Fluor company – described
as a leader in asset integrity
solutions – is experienced in
providing CUI inspections through
a number of non-destructive
testing (NDT) techniques and has
completed CUI inspections for a
wide range of companies across
New Zealand and Australia.
A favoured technique for CUI
inspection is digital radiography,
a non-invasive method which can
be used for wall loss type flaws
i.e. corrosion pitting, generalised
corrosion and erosion. Coupled
with the company’s unique
‘Open Vision’ screening tool, it
can complete large quantities
of pipework screening relatively
quickly without disruption to
production, saving the client both
time and money. One client, says
Stork, reported a cost saving of
between NZ $200,000 to $300,000
by not having to remove the
insulation.
In order to further mitigate the risk
of CUI resulting in an uncontrolled
release of ammonia, Stork offers
continued proactive monitoring,
finding vital information for accurate
life expectancy forecasting of the
refrigeration piping through erosion
corrosion inspection and wall
thickness monitoring.
For more information on how Stork
can assist with your CUI needs,
contact the team on 06 753 6169.
42 MARCH 2020