In-line Inspections (ILIs) and Pipeline Health - Pi Engineering

In-line Inspections (ILIs) and Pipeline Health

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“An ounce of prevention is worth a pound of cure”

Benjamin Franklin

In-line inspections (ILIs) and integrity digs are two critical components of routine buried pipeline maintenance and integrity programs. In-line inspections can yield much information about a pipeline’s health, including quantifying progressive pipeline movement as well as identifying a large variety of defects including pitting, cracks, out-of-roundness, dents, local wrinkling or global buckling. Closely related to in-line inspections are integrity digs, which are planned excavations to expose sections of the pipeline to execute planned repair procedures on identified integrity deficiencies.

Pi Engineering Inc. can help with post-ILI analysis by performing fitness for service (FFS) assessments, including bending strain analyses, to determine if an integrity dig is actually required or if the pipeline is suitable for continued service without mitigation. In the case that an integrity dig is required Pi Engineering can help ensure your repair is safe by performing stability and hot-tap stress analyses for the planned integrity dig.

Here’s a picture showing a pipeline that to our eye has something “not quite right” about it; the pipeline has upheaval buckled out of the ground, possibly due to a combination of insufficient ground cover, weak soils, erosion, and high operating temperatures. In this case, the pipe has been kind enough to expose itself for visual inspection, but this is not the way we would like to find this pipe. Careful examination of the output from an ILI performed with an inertial mapping unit (IMU) can indicate this type of integrity concern in a remote location without “walking the line.” Pi Engineering can help you design a safe strain relief program to return the pipeline to a code-compliant configuration.