Chemical Engineering March 2014 - 41

Phase 2 Initial Field Visit
Cover Story
Initiate visual
inspection of
quence events would occur if there
was a loss of containment. The team
must always fully understand the
operating process and include those
vessels that are frequently idle,
even if they operate in a temperature
range not usually noted for
susceptibility to CUI.
The team should be composed
of at least one member who is familiar
with the materials of construction
of the vessels and piping
being evaluated, as well as at least
one member knowledgeable in the
process temperatures at which the
equipment operates, and a member
knowledgeable about the CUI
damage mechanism. In addition
the team should include a member
who is familiar with the inspection
history of the vessels and piping
within the program.
The analysis team should use a
formalized approach to the determination.
A logic decision tree can
be very helpful (Figure 1).
The team's initial assessment
should pay particular attention to
the following equipment and piping
susceptible to CUI:
* Areas exposed to mist over-spray
from cooling water towers
* Areas subjected to process spills,
ingress of moisture or acid vapors
* Dead-legs and attachments; that
is, drains, vents and so on
* Pipe hangers and other supports
* Vibrating piping systems
* Steam-traced piping systems that
may experience tracing leaks
Phase 2
Phase 2 consists of a field walkdown
by qualified subject-matter experts
(SMEs). These experts determine
what non-destructive examination
(NDE) methodology is best suited
for discovering whether and how
CUI may be affecting each vessel
and piping system. The SMEs can
also determine the most efficient
and effective method for performing
the inspection and tests. Table
1 shows a brief analysis of NDE
methods that can be used to determine
the presence of CUI.
During the Phase 2 field assessment,
accessibility issues associated
with each piece of equipment and
Inspector
performs
visual asset
inspection
at exposed
locations
applicable assets -
Field walkdown
NO
Perform
engineering
assessment
to defer
inspection
Are
there any areas
with damaged
insulation
YES
YES
Document areas
on asset ISO
drawing.
Perform moisture
detection to isolate
suspect areas
Document areas on
asset ISO drawing
that are suspect
for CUI.
Establish
inspection
methodology
to be utilized
Determine
recommended
inspection plan
methodology
NO
Figure 2. In the field-walkdown
stage of the CUI program, subjectmatter
experts inspect equipment
to determine which method(s) will
be most effective to evaluating
whether and how CUI is affecting
each equipment item
Inspection
methodology
selection
Implement
inspection plan
Phase 3 Field Inspection
Field work and
follow up
inspection
Remove
insulation
at suspect
locations
Recommend
paint and
re-insulate asset
Document
recommendation
Follow-up
re-insulation
of asset and
close work
order
Inspection
complete.
Document finding
Mark ISO drawing
with location
inspected, update
asset files
Follow up
re-insulation
and close
work order
Excecute
inspection
plan
Follow up on
NDE findings and
make necessary
repairs
Perform
engineering
fitness for service
when required
Document
NO
YES
corrective action
Update ISO and
follow closure of
work order
and document
YES
Is
evidence of
corrosion present?
(cracks or
thinning)
YES
Inspector to decide between:
a. advanced NDE;
b. additional insulation removal;
c. engineering assessment;
d. combination of a, b, c options
piping can also be analyzed. Determining,
for example, where scaffolding
must be utilized or where rope
access is needed can be of significant
value. Rope access has made
a tremendous contribution to the
42 ChemiCal engineering www.Che.Com marCh 2014
Figure 3. When the field inspection
plan is carried out, the need for more
extensive testing can be determined
and possible recommendations for
repair can be developed
inspection and testing field. Inspectors
are able to perform any NDE
method from ropes, thus reducing
the need for scaffolding and greatly
reducing the cost of inspections.
There must be anchor points availNO
Does
paint
meet
plant
criteria?
Inspection
decision
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Chemical Engineering March 2014

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