POWER October 2011 - 76

PLANT DESIGN
field conditions can be explored, accurate
measurements taken, and general productivity
dramatically improved. Consider the
desire to limit the exposure of workers to
radiation at nuclear plants as a means of immediately
monetizing the value of converting
field work to office work.
Figure 2 shows two accurate laser images
of a plant. These are full 3-D images with every
pixel accurately known in 3-D space to
better than 5 mm. Though the images can be
rotated, panned, and zoomed to any perspective,
the included images represent a small
sample of what is possible.
3-D Virtual Models for Outages. Plant
outages are complex endeavors with myriad
distinct work packages involving significant
internal staff, and often hundreds (and sometimes
thousands) of contractors and suppliers.
3-D virtual models of the affected facilities enhance
communications and ensure team familiarity
with tasks and their environment without
time-consuming walkthroughs of the facility.
Specific views that support and inform
each individual work package are easily isolated
from the clutter of the real world and the
full 3-D virtual model. These are shared with
the staff, supporting workers, and contractors.
They capture and share knowledge about the
plant and planned work tasks. These views
are also combined for added perspective. For
example, structural steel views are combined
with piping views so that proper access and
routing can be planned and communicated
to outage staff. When needed, scaffolding
plans can be overlaid on the views to ensure
suitability. Nuclear plants have already documented
significant savings in scaffolding
alone in applying 3-D virtualization. In petroleum
processing plants, savings have been
documented on the order of 10% of the total
cost of the outage. This includes being able to
reduce the total down time by one-tenth.
3-D Virtual Models in Plant Maintenance.
In one petroleum refinery the issue
of temporary leak repairs was addressed. The
2. Believe it or not. Yes, these are laser scans, not photos. Courtesy: INOVx
specific concern was, " How to ensure that the
temporary repairs are made permanent in the
most efficient manner, by taking full advantage
of both planned and unplanned outages? "
Before the virtual model, it was very challenging
to identify all eligible temporary leak
repairs. With the virtual model, a temporary
repair database is dynamically linked to the
3-D virtual model, and all opportunities for
permanent repair are immediately highlighted
within the boundary of any outage activity.
Other applications of the 3-D virtual
model for plant maintenance are many and
varied. The impact on best practices is significant.
Maintenance personnel are able to
quickly locate lines, equipment, and instrumentation
and familiarize themselves with
components' location before going to the
field to perform their work. Work orders are
precisely linked to the target equipment or
system and, through that connection, to the
most current asset data. The model is a natural
tool for organizing and visualizing maintenance
history, operational data, test results,
and analysis.
Work order planning is greatly facilitated
by the 3-D model. Planners can develop libraries
of work packages for routine tasks
that are supported by their respective views
of the 3-D model. The net result is greater
productivity and quicker repairs, resulting in
shorter downtimes and greater utilization of
the plant.
3-D Virtual Models in Inspection and
Plant Integrity. In the past, inspection
3. A 3-D model of a corrosion inspection loop. The computer rendering has
replaced hand-drawn 2-D isometrics drawings. Courtesy: INOVx
circuits were documented using 2-D isometric
drawings with manual placement
of the thickness or corrosion monitoring
locations (TML/CML). In parallel, a database
was kept showing corrosion rate, date
of last inspection, and other data for each
point. The challenges in coordinating and
maintaining accuracy under this system
should be obvious.
Today, inspection circuits are generated in
3-D as a subset of the overall virtual model.
TML/CML points are called out in their exact
geospatial location and linked dynamically to
the source data. Even more important, these
inspection points are determined by using
the 3-D virtual model, permitting risk-based
techniques to be used that reduce the number
of inspection points by over 50% without increasing
plant operating risk. This has a double
benefit of reducing the total hours spent
inspecting the plant by 20% to 30% while increasing
its reliability and safety (Figure 3).
Inspectors use the 3-D virtual model to
determine scaffolding needs as well as access
limitations and safety requirements.
As one inspector from Shell Oil put it,
" One hour using the virtual model saves
me 8 hours in the field. "
76
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POWER October 2011

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