Pipeline Safety: Inspection, Mapping & Visualization Methods
Requirement
The following extract is a government perspective regarding pipeline safety, inspection, and public
awareness. Although highly controversial with some parties in the pipeline arena, and subject to revision
and approval, it underscores the importance of a comprehensive pipeline integrity plan, leveraging most
current technical methods.
"Proposed legislation is underway to provide for enhanced safety and environmental protection in pipeline
transportation, with particular emphasis in High Consequence areas. This proposed bill would reauthorize
the U.S. Department of Transportation’s pipeline safety program, provide additional protections for
critical areas, increase community knowledge about pipelines, improve investigation and enforcement
authorities, support underground damage prevention, enhance the state role in interstate pipeline safety,
and allow full compensation to states performing special investigations for the Department. This bill
assures that pipeline operators are more accountable to the public for the risks they impose, that federal
and state regulators have the tools they need to monitor that accountability, and that state and local
authorities have the information they need to live safely with pipelines.
This proposal adopts an approach to critical areas--densely populated or unusually sensitive to
environmental damage--that immediately benefits the public through emphasis on increased internal
inspections and testing and a focused attention on pipeline integrity. Many pipeline operators are
already adding protections for critical areas. This proposal provides the flexibility to continue those
efforts. At the same time, this proposal would provide the needed incentive to those operators that have not
moved quickly enough. It would give the Department enforcement and rulemaking authority to assure that
critical areas receive the attention they need. Because of the importance of the issues, the Department is
using existing regulatory authority to move forward to address increased protections for these critical
areas and expects to publish the first of a series of rules this spring. The statutory authority requested
would bolster this effort.
Recent experience indicates that communities need more information about pipelines. This proposal
reinforces the ability of communities to know what pipelines are in the community, the risks they pose,
and how to live safely with them. This proposal would enhance public education programs and increase
the information available to community responders and planners. It would also include state emergency
response commissions and local emergency planning committees established under the Emergency
Planning and Community Right-To-Know Act within the mix of state and local authorities who interact
with pipeline operators. Because of the importance of these issues, the Department has begun discussions
with citizen groups and state and local organizations about the needs in this area and ways in which they
can be met."
As this draft legislation states, significant emphasis has been given to inspection, data integration, analysis
and presentation of this data to the community. The ability to consolidate and analyze this data in an
expedient and accurate manner is the basis of this application framework presented.
Technology Integration
The location / geometry inspection tools used in pipelines utilize a combination of technologies: GPS, INS,
and GIS Systems in combination with traditional sensor arrays. These integrated geo-spatial capabilities
take corrosion and deformation surveys to a new level of analysis and accuracy. As a result, analysts have
a more complete information resource for:
- Detecting and characterizing pipe anomalies,
- Pinpointing locations of interest, and •Profiling the pipeline environment.
By combining pipeline location (and features) and presenting this location, attributes, and anomalies with
other information such as;
- aerial photography
- satellite imagery (multi-spectral),
- landownership, easements, right-of-ways,
- adjacent and intersecting pipeline and utility corridors,
- population centers,
- public and private facilities (schools, hospitals, etc.),
- transporation routes,
- ground cover classification,
- soil type surveys,
- digital elevation models,
- rivers, lakes, drainage, irrigation canals,
- environmental and special interest areas,
the analyst has a more complete picture. Combining this information provides a comprehensive
"prioritizing" tool for response, repairs / maintenance planning and risk-management decision-making.
GPS (Global Positioning System) survey methods provide the means to accurately position key "sparse"
points along the pipeline. This provides the absolute coordinate reference for the subsequent INS in-pipe
inspection operation. These surface points are spaced at varying intervals along the pipeline and directly
above the pipe, ranging from 1km to 5km separation. During the actual inspection run AGM's (above
ground markers) are placed at these locations that record a precise synchronized time tag of the tool
passage. Later correlation of these time events with survey position, provide calibration for the INS, and a
means to control and minimize position errors computed from the INS.
The INS (Inertial Navigation System) is the main sensor unit comprised of precision rate gyros (ring laser
or fibre optic) and accelerometers (Q-Flex) mounted on orthogonal 3-D axes and measuring at 100Hz rates
and higher. This gives the much needed resolution described earlier. The inherent error characteristics, thus
resultant accuracy of the INS are time based. These error sources, the most dominant being gyro drift, and
accelerometer biases, must be corrected on a continual basis. This is done using continuous velocity
derived from the odometer wheels that make contact with the inside pipe wall. Using advanced Kalman
Filtering, and empirical / optimal smoothing techniques, the INS error sources are controlled and accurate
position and attitude information produced. Thus, high resolution, accurate 3D position is produced, along
with pipeline curvature, which could not otherwise be provided by conventional methods.
The GIS (Geographic Information System) provides spatial analysis and visualization of the pipeline and
surrounding area. This spatial mechanism integrates inspection and positioning data with layers of spatial
information about the pipeline and environment, such as topography, population densities and aerial
photos, in both a planimetric map view, and profile view.
