Automated Pipeline As-Built Data Collection (TGP Reporter)
The Process
Review
Before moving forward lets take a step back and look at how we arrived at this
station. After all, we didn’t decide one day to just change the way we do
business. There were driving forces that necessitated a change in our business
processes and then business requirements that had to be met. This will be
discussed in greater detail following a review of how we used to do business.
Therefore let us now look at that old data collection process. I will illustrate how
our process worked. I will show you where we identified inefficiencies and risks
of data contamination. From there I will mention the driving forces that
necessitated a change in the data collection process and then review those
business requirements that drove the effort.
Typical Life Cycle of Field Book Data
The typical scenario of handling field books and field book data can be similar
between companies in our industry. It is also important to point out that many
companies have utilized programmatic ways to expedite a given piece of this
process. We were no different. We had programmatic solutions that were
departmentalized or fragmented from the rest of the company. Most companies
can identify with this natural progression of technology. As any technology
emerges, those who think outside the box are constantly looking for ways to push
that emerging technology. For instance, in our industry the generation of
alignment drawings from within a CAD program had been automated many years
earlier. Looking for a way to merge this programmatic solution with emerging
technology was an effort that thinking outside the box produced.
The following events briefly describe the life cycle of a field book and it’s data
for our past. Generally this is the process that occurred even though it could vary
by project or manager so long as the basic requirements set forth in our Field
Engineering Standards were met. Even today we may still utilize this old process
as we have found ourselves in a transition period between the old and the new.
Data Collected – Using traditional methods, a ground crew collected pipeline
As-Constructed data into field books. The number of survey crews required
could vary by project size and by number of spreads per project. Typically
there was crew per spread but there also no absolutes. The direction of
construction movement wasn’t really a factor as each page of the field book
stood on it’s own. Reversing out the “backward stations” was held to the end
and was labor intensive. Also, within the field book it was very easy to
account for laps, gaps and drags. These events were accounted for and
adjustments for them made at the end of the spread or project.
Final Survey - The final survey was then completed. This was to capture
points of intersections and proration points to adjust the preliminary data, if
used on the backside, to the as constructed data. This proration effort was an
early means to make use of good data already captured during the preliminary
ground survey.
Field Books Corrected – The As-Constructed data was collected into field
books during the stringing of the pipe. Once the data was collected, the field
books were “connected” to one another through recalculations. These
recalculations correct for reverse chaining brought about by construction
movement and accounted for the laps, gaps and drags. The stationing in the
field books reflected a one directional flow to facilitate calculations further
along in this process.
It is important to note that the data in the field books represented slope chain
data. This meant that the information was not horizontal-based. It reflected
the contour of the ground along the pipeline corridor.
Tally of Material – Prior to handoff of the field books to an engineering
department, the project accountants would make a final accounting of all
material. The field books came in very handy, as the stationing had been
recalculated to reflect a one directional flow. But, this was a labor intensive
manual process.
Engineering – The field book data was then passed to the engineering
department. The engineering department would immediately check the data
for errors. This required a very skilled person that usually had many years of
construction or related expertise. Found errors were rectified before moving
forward. Typically, by this time, the construction crew who captured the data
had returned to their home offices or moved on to other jobs. If errors were
found and could not easily be resolved in the back office this opened up a
whole set of metrics with which the engineering design group must now deal.
Alignment Drawings - Once the field books had been reviewed and checked
by engineering, the final As-built alignment drawings were created. At this
point let me mention that this stage often required a semi “start from scratch”
approach. The preliminary construction topography base could very often be
reused but was often stretched to fit the data from the field books that was
slope based. Without going into detail as to how this preliminary construction
base was put together, it is enough to mention that this topography was often
horizontal-based. Making this fit required a great deal of skill and was not for
the faint of heart. Oftentimes, some components of the topography base had
to be completely redrawn to account for the slope stationing.
Routing and Distribution - Once the completed As-built drawings had been
completed and again checked against the field book data they were routed for
appropriate signatures and then distributed. This usually marked the end of
the life cycle of the construction effort; but, not necessarily the end of using
the field book data.
Compliance Services – Within our industry, certain federal, state and local
regulations dictate how we must operate our system. One particular
compliance activity is the classification of the new pipeline facilities. Here,
among other things, we identify the house density within and along our
pipeline corridor. This density count required a new set of alignment-based
drawings called Classification Drawings. These Classification Drawings were
not completed until the As-built alignment drawings had been approved and
distributed.
Traditionally, these Classification Drawings used rectified aerial photography.
These aerial photographs were created after construction to enable the pipeline
scar to be visible. Rectified photography removes the curvature of the earth
and allows the image to be seen as a true horizontal base. Did I mention that
our As-built drawings were completed based on the field book data that was
slope chained? The creation of these Classification Drawings was almost and
art.
So, what am I attempting to illustrate with the above process? I’m illustrating the
labor-intensive process that data from a field book undergoes to produce the final
product. Yes, it is probable that technology was used in various degrees at
various stages. But, that technology was department specific and wasn’t
necessarily a method that allowed the data to be utilized across the enterprise as
an asset.
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