The Eye in the Sky, Squealing Pigs, and Other Pipeline Mysteries Revealed

Buried pipelines transport the energy needed to operate our businesses, homes, and farms.

Over 2.5 million miles of pipeline in the US lay beneath farmland, ranchland, and across our country. Pipelines are the safest mode of transportation in the United States. A barrel of crude oil or petroleum product shipped by pipeline reaches its destination safely more than 99.9999% of the time.

Pipeline operators work hard to ensure that health, safety, security, and environmental concerns are all addressed. Pipeline companies work to prevent releases by evaluating, inspecting, and maintaining pipelines in a program called Integrity Management. Much of the activity you see out on the pipeline right-of-way (ROW) is company personnel ensuring the safe and reliable operation of the system.

Some of the common activities you may notice qualified pipeline representatives performing:

Aerial Patrol

Pipeline representatives fly over pipelines at regular intervals to perform inspections. They look for discolored ground, dying vegetation, or a sheen on the water as signs of a possible leak.

Nearby construction is noted and a call to the local field office is made. Pilots look for buildings or obstructions on the ROW (called encroachments). Pipeline patrol is an essential element of Integrity Management programs.

In-Line Inspection and Maintenance “Pigging”

For many years, the pipeline industry has used devices to clean the inside of pipelines. These devices, called “pigs,” scrub and scrape waxes and other contaminants that can build up on the interior walls. The first such devices were made of straw and wire and made a squealing noise as they traveled through the pipeline, thus earning the name “pigs.”

Today, high-tech in-line inspection (ILI) tools travel through the pipe and measure and record irregularities that may represent corrosion, cracks, laminations, deformations (dents, gouges, etc.), or other defects. Because they run inside the pipe in a manner similar to the scrubbing and scraping devices known as pigs, these inline inspection tools are often referred to as “smart pigs.”

Right-of-Way (ROW) Clearing

The pipeline ROW must be kept clear of trees, tall vegetation, or structures. The pipeline patroller’s visual inspection cannot be impeded by tree canopies, buildings, or other encroachments. It is also important to keep the pipeline ROW free of trees because roots can damage the protective coating of the pipeline, and in case of an emergency, responders need to be able to access the area quickly.

Mainline Valve Inspections

Pipeline systems have valves located throughout the entire system. These valves are used to isolate sections of the pipeline when conducting maintenance or in case of an emergency. Routine inspections verify that the valves operate properly.

Hydrostatic Testing

Hydrostatic testing can be an important part of the pipeline’s integrity management program. During the test, the pipeline is filled with water at pressures higher than normal operating pressures. The water is colored using an environmentally safe dye, so if there is a leak, it can be identified, and repairs can be made. Hydrostatic testing can last 8-12 hours or more and is a safe and effective way to proactively look for problems that could result in a release.

Corrosion Inspections

In its natural state, metal corrodes at various rates depending on the material. Pipeline companies use different methods to protect against corrosion and ensure safe operation,
including sophisticated coatings and cathodic protection (electric currents) to fight against
corrosion. When a pipeline is properly installed and maintained, it can operate safely virtually endlessly. Pipe-to-ground and close interval inspections ensure corrosion protection is operating properly.

Originally published in the 2021 PASA Farm & Ranch Excavation Safety Guide

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