16-Inch InVista Tool Case Study: Navigating the Bends
By: Lilly Darnell, Senior Marketing Specialist, Quest Integrity Group
As seen in the December 2012 edition of Pipelines International. Download the PDF version.
For the inspection of this line, the 16-inch InVista tool
was propelled in diesel and achieved a scan rate of approximately 0.3 meters
per second (m/s). The tool traveled a total of 471.9 m. The inspection took approximately two hours to
complete, and all of the data was collected in one run. Upon retrieval of the
tool, the ultrasonic (UT) measurement data was downloaded and prepared for
An API 579-1/ASME FFS-1 2007 fitness-for-service (FFS) assessment was performed
on the single-diameter line.
The inspection data was analyzed for wall thinning, and anomalies such as
corrosion, denting and ovality were determined using the LifeQuest pipeline
software. The remaining strength factor (RSF) and reduced maximum allowable
operating pressure (MAOP) for the pipe were also determined.
This assessment is based on the longitudinal extent of thinning found in the
pipe and in accordance with a Level 2 assessment as found in Part 5 of the API
579-1 standard. Results from the assessment
• 110 external metal loss anomalies were individually identified. The greatest
of these anomalies corresponded to 72 percent wall loss, based on nominal wall
thickness. The industry standard is to immediately address wall loss between
60–80 per cent
• Four dents in excess of 0.5 percent nominal outside diameter (OD) were
identified. The largest identified dent had a depth of 0.8 per cent nominal OD
• The minimum MAOP calculated according to Part 5 Level 2 assessment
methodology in API 579-1 was 4.0 MPa.
|Figure 1: 2D and 3D views of external
|Figure 2: 2D and 3D views of a dent.
|Figure 3: The pipeline integrated
The InVista technology is a light-weight tool that can be hand-carried, lifted
and loaded. It performs in low flow/low pressure environments and can navigate
1.0D bends, including back-to-back and mitre bends. It was designed to overcome
challenges associated with traditionally difficult-to-inspect and unpiggable
pipelines. InVista easily negotiates damaged and restricted pipe with
minimum passage and tight, back-to-back bends. The tool can run in low-pressure
environments, and its bi-directional capability allows it to be launched and
received at the same location, minimizing or eliminating line
InVista’s unique design reduces operational risk by minimizing the wear, impact
and debris collection that is associated with conventional in-line inspection
technologies. The tool provides accurate and repeatable results with its direct
high-density UT measurement.
The assessment is comprehensive and includes all line data versus individual
Cost effective and time-efficient
An InVista inspection is cost-effective. Data are collected in a single
pass and the combined geometry and metal-loss data provide 100 per cent
overlapping coverage. The tool minimizes offline status, as it inspects efficiently and allows real-time operating decisions with its on-site
turnaround and rapid data analysis – saving time for the operator. Linear UT
sizing minimizes verification digs, improving excavation and repair confidence,
and permanent line modifications are not required. In addition, it eliminates demagnetization
repairs because UT inspections do not permanently magnetize the pipe.
Benefits of the single-module tool
• Lightweight; the tool is handled and transported easily, reducing safety and
• Longer battery life and faster on-board computing for greater axial flaw
resolution and increased inspection velocity, providing accurate results and
• Ideal for space-constrained environments such as terminals, refineries and
For more information visit the webpage.
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